Perfusion maps based on temporal blood-oxygen-level-dependent signal delays are driven by alterations in low frequency oscillations between 0.01 and 0.1 Hz
A. Khalil1,2, E. Kirilina3, K. Villringer1, J. Fiebach1 and A. Villringer2,4
1Charité - Universitätsmedizin Berlin, Center for Stroke Research Berlin, Berlin, Germany
2Max Planck Institute for Human Cognitive and Brain Sciences, Department of Neurology, Leipzig, Germany
3Free University Berlin, Center of Cognitive Neuroscience Berlin, Department of Education and Psychology, Berlin, Germany
4Berlin School of Mind & Brain, Berlin, Germany
Abstract
Objectives: Assessing brain perfusion without the need for intravenous contrast agents can be achieved by examining the temporal properties of the blood-oxygen-level-dependent (BOLD) signal [1]. We investigated the characteristics of these perfusion-related BOLD signal changes in stroke patients.
Methods: Six patients with acute ischemic stroke received a multiband echo planar imaging sequence (repetition time = 0.4 s, echo time = 30 ms, acquisition time = 340 s, flip angle = 43, sensitive to the BOLD signal) and a standard stroke MRI protocol within 24 hours of symptom onset. The BOLD data underwent spatial independent component analysis (sICA [2]) and time shift analysis (voxelwise cross-correlation with global signal [1]) after bandpass filtering to the following frequencies: low-frequency oscillations (LFOs, 0.01–0.1 Hz), respiration (0.2–0.5 Hz), and cardiac (0.5–1.2 Hz). Bolus-tracking MRI data (time-to-maximum of contrast concentration-time curve, Tmax) are shown for comparison.
Results: Hypoperfusion components from sICA were visually identified based on comparison to Tmax maps. These results, along with the time shift analysis maps, are shown for a representative patient in the figure. The spatial distributions of the power in the different frequency bands are also shown [3]. Hypoperfusion showed predominantly slow (<0.05 Hz) BOLD signal oscillations and was not identified using sICA or time shift analysis in the respiratory or cardiac frequency bands in any of the patients.
Conclusions: Hypoperfusion-related changes in the temporal dynamics of the BOLD signal occur due to alterations in LFOs, not cyclical cardiac or respiratory activity. They are likely due to slow variations in physiological processes reflected in the BOLD signal.
References
[1] Lv et al., Ann Neurol, 2013
[2] Khalil et al., ESMRMB 33rd Annual Meeting, 2016
[3] Tong & Frederick, Front Hum Neurosci, 2014
PS02-002
Poster Viewing Session II
A multidisciplinary sysytems biology approach to neuronal remodelling post Ischemic Stroke injury using endogenous adult neural stem cells
and S. Kapoor1
1National Brain Research Centre, Neuroimaging and Computational Neuroscience, Delhi, India
Abstract
Objectives: The aim of the study is to develop a cell-based neuro-restorative therapy model for stroke using a multi-disciplinary approach combining systems biology tools and computational modelling, followed by in-vivo verification.
Methods: The phenomena of neurogenesis (Neural stem cell proliferation), cell migration and synaptogenesis, from the Sub-Ventricular Zone (SVZ) towards the Stroke's penumbra (1), under the influence of therapeutic growth factors were modelled for optimal patient recovery.
Meta-Core, an omics based systems biology platform, was used to predict effective drugs that could optimise the physiological processes (2).
Post drug selection, a predictive cell kinetics mathematical model including neurogenesis, migration and subsequent differentiation, along with supportive angiogenesis, into niche specific neurons leading to neurorestorative recovery was designed.
This was followed by Middle Cerebral Arterial Occlusion technique (3) on which biochemical and MRI assessment was performed.
Results: We observed a peak of maximal neurogenesis at specific drug dose and duration with 19% synaptogenic efficiency. The predicted time of sensorimoror recovery of 3–4 weeks concur with experimental findings based on MRI and histopathology studies (4).
Conclusion: Our efforts can be seen as the first endeavour of utilising computational tools to design targeted neurorestorative therapy platforms that would allow for incorporation of patient specific parameters which could serve as indicators for recovery.
References
1. Alvarez-Buylla et al (2000) The subventricular zone: source of neuronal precursors for brain repair. Prog Brain Res.;127:1–11
2. MetaCore Data-mining and pathway analysis manual, Evaluating statistical significance of pathways and network in MetaCore
3. Garcia JH et al. (1993) Progression from ischemic injury to infarct following middle cerebral artery occlusion in the rat. Am J Pathol; 142:623–635
4. Thored P et al. (2006) Persistent Production of Neurons from Adult Brain Stem Cells During Recovery after Stroke, Stem cells; 24:739–47
PS02-003
Poster Viewing Session II
Ischemic preconditioning renders long-term protection against stroke: roles of GSK3β inhibition and anti-oxidative enzyme upregulation
Y. Sun1, T. Yang1, M. Zhang1, J. Chen1 and F. Zhang1
1University of Pittsburgh, Neurology and PIBDR, Pittsburgh, United States
Abstract
Objectives: Ischemic preconditioning (IPC) induces ischemic tolerance against subsequent lethal stroke; however, the underlying protective mechanisms are not fully understood. Glycogen synthase kinase 3 beta (GSK3β) plays detrimental roles in stroke; one of them is to facility the degradation of Nrf2. The aim of this study is to investigate the role of GSK3β inhibition in inducing ischemic tolerance, focusing on activation of Nrf2 and upregulation of its downstream enzymes.
Methods: IPC was induced in male wildtype and Nrf2 KO mice by 12 min MCAO, and lethal stroke was induced by 60 min MCAO. Long-term sensorimotor (7d), cognitive functions (35d), and ischemic outcomes were examined. In vitro, OGD was applied to rat primary neuronal cultures, 12 min for PC, and 60 min for ischemic condition. The phosphorylation and enzymatic activities of wildtype or mutants of GSK3β were evaluated.
Results: Compared to the control, IPC mice showed improved neurological performances on rotarod and adhesive removal tests, improved learning and memory in Morris water maze test, and reduced tissue loss at 35d (n = 8); however, this protection was abolished in Nrf2 KO mice. IPC increased Nrf2 DNA binding activity and upregulated HO-1. In vitro, PC strongly activated Nrf2 and induced HO-1, and protected neurons against OGD. Nrf2 knockdown with shRNA abolished the protection. Further studies showed that PC led to the generation of α, β unsaturated carbonyls, including 4-hydroxynonenal (4-HNE), which played a key role in activating Nrf2. 4-HNE reacted with PTEN and inhibited its activity, contributing to increased levels of p-Akt and p-GSK3β in the brain. Moreover, 4-HNE not only inhibited the activities of wildtype GSK3β but also the constitutively active S9A mutant.
Conclusion: IPC leads to mild oxidative stress, generating α, β unsaturated carbonyls. These carbonyls inhibit GSK3β activity by phosphorylation or probable direct interaction, contributing to Nrf2 activation.
PS02-004
Poster Viewing Session II
Superselective Administration of VErapamil during recanalization in acute ischemic stroke (SAVER-I): study results
J. Fraser1,2,3, D. Lukins4, L. Parker1, W.L. Stafford4, A. Alhajeri1,4 and G. Bix1,2,3
1University of Kentucky, Neurological Surgery, Lexington, United States
2University of Kentucky, Neurology, Lexington, United States
3University of Kentucky, Anatomy and Neurobiology, Lexington, United States
4University of Kentucky, Radiology, Lexington, United States
Abstract
Objectives: Multiple trials have shown endovascular thrombectomy (ET) to be an effective therapy for emergent large vessel occlusion (ELVO) stroke, though clinical outcomes vary significantly. To address this, we coupled ET with a potential neuroprotective pharmacotherapy. We recently demonstrated intra-arterial (IA) verapamil was safe, reduced infarct volume, and improved functional outcome in a rodent model. We conducted a Phase I clinical trial, Superselective Administration of VErapamil During Recanalization in Acute Ischemic Stroke (SAVER-I) to study safety and feasibility.
Methods: Adult consecutive patients with ELVO undergoing ET were considered for enrollment if not anticoagulated. Once successful thrombectomy was performed, 10mg of verapamil in 20 cc of normal saline was administered IA into the vessel of occlusion. The primary endpoint was the presence/absence of significant intracranial hemorrhage (sICH) within 24 hours after treatment. Secondary objectives included systemic side effects of verapamil at the time of administration, technical feasibility, radiographic stroke volume, and modified Rankin scale at 90 days.
Results: Of 104 consecutive patients undergoing thrombectomy at University of Kentucky, 11 were successfully enrolled. Among the 93 not enrolled, 10mg of IA verapamil given as standard of care for vasospasm did not significantly change hemorrhage risk. Of the 11 enrolled, none had a significant intracranial hemorrhage. There were two periprocedural adverse events recorded during the thrombectomy procedure; one self-limited desaturation and one seizure. All but one subject received intravenous tPA as standard of care. Successful drug delivery was achieved in all cases without thromboembolic complication. Median infarct volume was 24.0 cc with a range of 1.7–163.3 cc. Of the survivors, the rate of independence (mRS of 0–2 at 90 days) was 44.4%.
Conclusions: Superselective IA pharmacotherapy immediately following endovascular thrombectomy is safe and feasible. IA verapamil may represent a safe and potentially therapeutic option.
PS02-005
Poster Viewing Session II
Association of depression polygenic risk and ischemic stroke in the stroke genetics network (SiGN)
S. Wassertheil-Smoller1, Q. Qi1, T. Dave2, B.D. Mitchell2, J.W. Smoller3,4 and D. Woo5
1Albert Einstein College of Medicine, Epidemiology and Population Health, Bronx, United States
2University of Maryland School of Medicine, Medicine and Epidemiology and Public Health, Baltimore, United States
3Harvard University Massachusetts General Hospital, Psychiatry, Boston, United States
4Harvard University T.H. Chan School of Public Health, Epidemiology, Boston, United States
5University of Cincinnati, Neurology and Rehabilitation Medicine, Cincinnati, United States
Abstract
Background: Large epidemiological studies have demonstrated that depression is associated with increased risk of stroke. It remains unclear whether genetic variants associated with depression are related to stroke.
Methods: We examined whether a polygenic risk score (PRS) based on the largest available genomewide association analyses of major depressive disorder from the Psychiatric Genomics Consortium is associated with stroke risk, using individual level GWA data pooled across the 22 international cohorts of the Stroke Genetics Network (SiGN). Logistic regression analyses treated PRS as a continuous variable, in 12,577 cases and 25,643 controls of European ancestry and 1353 cases and 2383 controls of African ancestry, to assess relationship of PRS to ischemic stroke and its subtypes. The PRS used 83,890 SNPs with p value threshold for inclusion of 0.5 although we tested various other thresholds ranging from p = .001 to 0.5.
Results: We found a significant positive relationship in European ancestry analyses between PRS and all stroke (p = .028) and the subtype of Small Artery Occlusion (SAO), N = 2029 cases. There was also a relationship of PRS to cardioembolic stroke (CE), (N = 3400, p = .0375), but no relationship between PRS and large artery atherosclerosis or other subtype. In the much smaller sample of African ancestry, we also found a relationship between PRS and all stroke (p = .0076), SAO (N SAO = 390, p = .024) and LAA (N LAA = 220, p = .028), but no relationship to CE (N (CE) = 208).
Conclusion: Higher polygenic risk score for depression is associated with higher risk of ischemic stroke, particularly in the subtype of small artery occlusion. This is the first study to provide evidence of genetic relationship between depression polygenic risk and stroke, suggesting a potential mechanism contributing to the previously demonstrated phenotypic association between stroke and depression.
PS02-006
Poster Viewing Session II
Genome-wide association studies from the Vitamin Intervention for Stroke Prevention (VISP) trial detect novel loci for recurrent stroke
K. Keene1, W.-M. Chen2, F.-C. Hsu3, S. Williams2, M. Sale2 and B. Worrall2
1East Carolina University, Biology; Center for Health Disparities, Greenville, United States
2University of Virginia, Charlottesville, United States
3Wake Forest School of Medicine, Winston-Salem, United States
Abstract
Recurrent strokes, which account for ∼25% of all strokes annually, are more deadly and most likely to cause disability when compared to a first stroke. Unfortunately, genetic studies of recurrent stroke have been severely lacking. Our group has completed a genome-wide association study, identifying two novel loci associated with recurrent stroke in the Vitamin Intervention for Stroke Prevention (VISP) clinical trial population. A subset of 2,100 VISP participants were genotyped on the Illumina HumanOmni1-Quad BeadChip and survival analyses, in which days of follow-up to recurrent stroke was regressed on gender, age, treatment group, and principal components 1–4, were performed. These analyses detected two genome-wide significant associations (rs6664786; Beta = −0.62, P = 1.73 × 10-8 and rs2184006; Beta = −0.62, P = 3.43 × 10-8) located in a gene sparse region of chromosome 1. Three additional SNPs in this region had nominal P-values ranging from 7.60 × 10-7 to 8.23 × 10-6.
Subsequent treatment-stratified analyses of recurrent stroke, using Cox proportional hazards regression survival analysis, identified a cluster of nearly a dozen SNPs on chromosome 2 with genome-wide significant associations for recurrent stroke in the low dose treatment arm (adjusting for age, sex, and the top 5 principal components). The top SNP, rs6542775 (Beta = −1.966, P = 2.19 × 10-11) is located downstream of the LIM and senescent cell antigen-like domains 1 (LIMS1) gene. Kaplan-Meier survival analyses by genotype for the top SNP, rs6542775 revealed that individuals in the low dose treatment arm carrying the GG genotype had significantly higher probability of longer survival (not suffering a recurrent stroke) than those with either the GA or AA genotypes (P = 6.1 × 10-8). Collectively, our findings suggest that variants across these two regions may have implications with regards to recurrent stroke risk and potential therapeutic response. We are currently seeking replication populations to validate these findings.
PS02-007
Poster Viewing Session II
Differential DNA methylation loci implicated in measures of homocysteine from the Vitamin Intervention for Stroke Prevention (VISP) trial
N. Davis1, W.-M. Chen2, M. Brewer1, S. Williams2, M. Sale2, B. Worrall2 and K. Keene1
1East Carolina University, Greenville, United States
2University of Virginia, Charlottesville, United States
Abstract
DNA methylation, a widely accepted dynamic epigenetic factor, may play an important role in human disease. In the case of stroke, the folate one carbon metabolism (FOCM) pathway is a logical link between DNA methylation and stroke and vascular disease risk.
Our primary goal is to address the relationship between DNA methylation, stroke risk, and measures of homocysteine (Hcy), and identify CpG sites/regions with significant deviations in DNA methylation patterns. We have generated DNA methylation data for more than 450,000 CpG sites in 180 individuals with stroke from the Vitamin Intervention for Stroke Prevention (VISP) clinical trial using the Illumina Infinium 450K BeadChip. Ethnicity stratified genome-wide epigenetic analyses (eWAS) for Hcy were performed using linear regression techniques, accounting for age, sex, batch, PCAs, and cell type proportions, in African Americans (n = 76) and European Americans (n = 104). Our preliminary analyses for Hcy in European American participants only, identified eleven statistically significant p-values at a Bonferroni-adjusted genome-wide threshold of 1.05 × 10−7. The most significant differentially methylated CpG site for Hcy in European-Americans was located on chromosome 15, a CpG site located within the GOLGA8A gene. The Golgin A8 Family, Member A (GOLGA8A) gene is a protein-coding gene that is involved in maintaining Golgi structure. Increased GOLGA8A levels have been observed in blood from intracerebral hemorrhage patients, however the role of GOLGA8A has yet to be elucidated in relation to intracerebral hemorrhage. Although preliminary, no loci reached genome-wide significance in the African American only analyses. Our findings support the utility of DNA methylation approaches to interrogate epigenetic factors contributing to stroke related phenotypes specifically in VISP, but these approaches could be extended to additional measures of homocysteine (e.g. post methionine load Hcy) and qualitative phenotypes such as recurrent stroke.
PS02-008
Poster Viewing Session II
GISCOME - genetic influences on ischaemic stroke functional outcome: a genome wide association study
J. Maguire1,2,3, C. Jern4, A. Lindgren5,6, B. Worrall7, J.-M. Lee8, S. Bevan9, I. Fernandez-Cadenas10,11, D. Woo12, J. Jimenez-Conde13, V. Thijs14, N. Rost15, J. Rosand15, C. Levi2,3, K. Rannikmae16, K. Jood17, J. Sturm1, T. Tatlisumak4, T. Wieloch5, R. Lemmens18,19 and D. Strbian20
1University of Newcastle, Faculty of Health and Medicine, Callaghan, Australia
2Hunter Medical Research Institute, Newcastle, Australia
3University of Newcastle, Priority Research Centre for Stroke and Traumatic Brain Injury, Newcastle, Australia
4University of Gothenburg, Clinical Genetics, Sahlgrenska Academy, Gothenburg, Sweden
5Lund University, Department of Clinical Sciences, Neurology, Lund, Sweden
6Skane University Hospital, Department of Neurology and Rehabilitation Medicine, Lund, Sweden
7University of Virginia, Departments of Neurology and Health Evaluation Sciences, Charlottesville, United States
8Washington University in St. Louis School of Medicine, Department of Neurology, St. Louis, United States
9Lincoln University, Lincoln, United Kingdom
10Vall d’Hebron Institute of Research, Barcelona, Spain
11Fundació Docència I Recerca Mutuaterrassa, Mutua de Terrassa Hospital, Terrassa, Spain
12University of Cincinnati, College of Medicine, Cincinnati, United States
13Department of Neurology, Institut Hospital del Mar d’Investigació Mèdica, Barcelona, Spain
14Austin Hospital, Melbourne, Australia
15Harvard Medical School, Boston, United States
16Edinburgh University, Edinburgh, United Kingdom
17University of Gothenburg, Sahlgrenska Academy, Gothenburg, Sweden
18University of Leuven, Department of Neurosciences, Experimental Neurology, Leuven, Belgium
19Leuven Research Institute for Neuroscience and Disease, Leuven, Belgium
20Helsinki University Central Hospital, Department of Neurology, Helsinki, Finland
Abstract
Background and Aim: Genome-wide association studies (GWASs) continue to identify novel genetic factors for stroke risk, and accumulating evidence suggests that genetic factors contribute to variation in stroke outcome. The Genetics of Ischemic Stroke Functional outcome (GISCOME) network is a collaborative aimed at performing meta-analyses and additional investigations of outcome related phenotypes.This presentation will describe the cohorts and methods.
Methods: This network has assembled 13 cohorts of ischemic stroke (IS) patients with GWA and outcome data from the International Stroke Genetics Consortium (ISGC) and the National Institute of Neurological Diseases and Stroke (NINDS) Stroke Genetics Network (SiGN) initiatives. Surveys were performed to determine availability of outcome and covariate variables plus time-points for when data had been collected.
Results: Modified Rankin score (mRS) determined at 60–190 days after index stroke was chosen as suitable time range for mRS functional outcome measure. To date, we have assembled 7,141 phenotyped cases with GWAS data. We detected heterogeneity between cohorts for age and initial stroke severity (NIHSS). We intend to conduct the first phase GWAS and then expand to the second phase of this effort with data we expect to obtain from new contributing sites with summary data.
Conclusion: We present a unique retrospective cohort of IS cases with detailed genetic and outcome data which provides an opportunity for discovery of novel genetic loci that may influence functional outcome. In addition, GISCOME will be interrogated to address candidate gene replication and related functional outcome hypotheses.
PS02-009
Poster Viewing Session II
A network approach to identifying new candidates for stroke and stroke subtypes
S. Williams1, K. Keene2, R. Malik3, Q. Yang4, T. Dave5, B.D. Mitchell5, S. Seshadri6, M. Sale7 and B. Worrall1
1University of Virginia, Neurology, Charlottesville, United States
2East Carolina University, Biology, Greenville, United States
3Klinikum der Universität München, München, Germany
4Boston University, Biostatistics, Boston, United States
5University of Maryland School of Medicine, Baltimore, United States
6Boston University, Neurology, Boston, United States
7University of Virginia, Public Health Sciences, Charlottesville, United States
Abstract
Efforts to identify genetic variation in ischemic stroke have demonstrated recent successes. However, actionable targets or pathways have not been tractable. Weighted Gene Co-Expression Network Analysis (WGCNA) uses an unsupervised method that clusters genes based on their expression profiles into “modules.” Modules contain genes that are likely biologically related to each other. Genes with high correlation to the overall expression profile of a module, the eigengene, are typically the most biologically relevant and can be used to inform genome-wide association studies (GWAS), potentially leading to identification of translational targets.
We performed WGCNA using a publicly available gene expression dataset (GSE43292) of 34 carotid atherosclerotic plaques and paired distant normal carotid tissue. Hierarchical clustering resulted in 16 distinct modules. Five were associated with carotid atheroma, and one stood out as an excellent candidate [Stroke Module (SM)]. Enrichment analysis showed that SM contains genes associated with vascular disease traits, ischemic stroke (IS), and subtypes; however, many of the most highly connected SM genes are novel candidates. We conducted GWAS for IS informed by SM “hubs” (module r2 > 0.9) using only known functional arterial genetic variants, as per the Genotype-Tissue Expression (GTEx) project, in METASTROKE (cases = 12,389, controls = 62, 004) with replication in the Stroke Genetics Network (SiGN) (cases = 17,000, controls = 32,000). We identified significant SNP associations of ADAMTSL3 with IS (p = 3.65×10−05, replication p = 9.67×10−03). ADAMTSL3 is an excellent stroke candidate with translational potential being a protein family member known to regulate clotting. ADAMTSL3 is also down-regulated in carotid atheroma in our dataset (p = 1.78×10−05).
In conclusion, we identified novel carotid atheroma candidates using WGCNA and used this data to inform genetic analyses of IS. We then showed, and replicated, association of ADAMTSL3 gene variants with IS, a gene with excellent translational potential.
On behalf of: METASTROKE at Boston University, Stroke Genetics Network (SiGN) at Harvard Medical School
PS02-010
Poster Viewing Session II
Manipulation of cerebral blood flow through postural changes in pediatric stroke
D.R. Busch1,2, T. Ko2, T. Boorady1, J. Newland1, K. Mensah-Brown1, J. Lynch1,2, M. Winters1, A. McCarthy1, L. Beslow1, E. Buckley3, T. Durduran4, A. Yodh2 and D. Licht1
1Children's Hospital of Philadelphia, Philadelphia, United States
2University of Pennsylvania, Philadelphia, United States
3Georgia Institute of Technology, Atlanta, United States
4ICFO - Institut de Ciències Fotòniques, Casteldefells, Spain
Abstract
Objectives: Ischemic stroke therapy is focused on maximizing cerebral blood flow (CBF) to minimize further damage to the stroke penumbra. However, management strategies are generally empirical due to the absence of bedside CBF monitoring. Most stroke patients are kept supine after stroke onset to increase perfusion pressure. Prior work in adult stroke patients demonstrated that CBF generally increases with decreased HOB angle. However, a paradoxically lower supine CBF was observed in ∼20% of stroke patients; thus, a supine position may be detrimental for some. Pediatric stroke is much less well studied than adult stroke and has different etiologies yet, it is one of the top ten causes of pediatric mortality and has few current therapies. Here, we describe measurements of cerebral blood flow during postural manipulation in children with recent ischemic stroke.
Methods: Diffuse optical and correlation spectroscopies provide rapid, quantitative, and non-invasive measurements of blood oxygenation, volume, and blood flow, as validated against several clinical techniques in the pediatric brain, including ASLMRI. We have applied these tools during postural manipulation from a supine to sitting position in pediatric ischemic stroke patients and healthy controls.
Results: We have measured 8 pediatric stroke patients and matched controls. Consistent with prior measurements, we observe lower or minimally changed CBF in the supine position, compared to the seated position, in a subgroup. Intriguingly, we also observed that when subjects were returned to a supine position after being seated at 30o for 5 minutes, ∼80% of subjects showed a ∼25% increase in CBF compared to initial supine flow, suggesting a potential therapeutic intervention.
Conclusion: These results suggest that bedside monitoring of microvascular CBF is desirable for identification of patients for whom the standard of care supine position could be deleterious. Additionally, postural manipulation may be useful to raise cerebral blood flow.
PS02-011
Poster Viewing Session II
Oxytocin is neuroprotective against physiological and behavioral consequences of social stress
1Krasnoyarsk State Medical University named after Prof. V.F. Voino-Yasenetsky, Department of Biochemistry, Medical, Pharmaceutical & Toxicological Chemistry, Research Institute of Molecular Medicine & Pathobiochemistry, Krasnoyarsk, Russian Federation
Abstract
Brain plasticity refers to the remarkable property of the neurons to change their structure and function, in response to experience, associated with cognitive functions and social behavior performance and a major focus for neural rehabilitation following wild spectrum of brain disease. Oxytocin is able to modulate the social behavior of animals and human, including sexual behavior, social interactions between individuals, maternal and paternal behaviors, the interaction of the mother with a newborns, and activates the neuroplasticity that is needed for learning and change. Mice are social animals and an applicable tool to investigate brain plasticity and repair at the molecularl-cellular level responsible for the development of brain adaptation in different environmental experience. Studying the role of specific environmental factors in the pathology of the brain plays an important role in determining the molecular and cellular mechanisms of action of environmental stimuli. Oxytocin release differed markedly between individual mice under stress. Our research is aimed to study the changes in cognitive function, emotional status and social behavior in CD-1 mice kept under different conditions: enriched environment, standard, paired or single housing. The behavioral changes and plasma oxytocin levels were evaluated dynamically one time per week during the experiment. At the end the full battery of behavior tests was performed. Brain samples were collected to assess the level of oxytocin and ADP-ribosyl cyclase activity, oxytocin release from isolated nerve ending of hypothalamus and pituitary. We found environment-induced changes in oxytocin levels associated with development of behavioral patterns specific for all the conditions tested. And oxytocin treatment modulates behavioral responses in fear conditioning test.
PS02-012
Poster Viewing Session II
Oxidative stress-Responsive Apoptosis-Inducing Protein (ORAIP) plays a critical role in cerebral ischemia/reperfusion injury
M. Kishimoto1, J. Suenaga1, H. Takase1, K. Araki1, T. Yao2 and Y. Seko2
1Yokohama City University Graduate School of Medicine, Department of Neurosurgery, Yokohama, Japan
2Institute for Adult Diseases, Asahi Life Foundation, Division of Cardiovascular Medicine, Tokyo, Japan
Abstract
Objectives: Oxidative stress plays a critical role in the pathogenesis of ischemia/reperfusion (I/R) injury that leads to apoptosis. We previously identified a novel apoptosis-inducing humoral factor in a conditioned medium of cardiac myocytes subjected to hypoxia/reoxygenation. We named this novel posttranslationally-modified secreted form of eIF5A as Oxidative stress-Responsive Apoptosis Inducing Protein (ORAIP) (Sci Rep 2015;5:13737). We confirmed that rat myocardial I/R injury was significantly suppressed (more than 40%) by treatment with neutralizing anti-ORAIP monoclonal antibodies (mAbs). The purpose of this study is to investigate whether ORAIP is a critical molecule in cerebral I/R injury as in myocardium in vivo.
Methods: Male spontaneously hypertensive rats (SHR) were randomly assigned into 4 groups of (I/R+vehicle pre-treatment), (I/R+vehicle post-treatment), (I/R+anti-ORAIP mAb pre-treatment), and (I/R+anti-ORAIP mAb post-treatment). Vehicle or mAb was infused into the left lateral ventricle. A transient cerebral I/R model was made by occluding the left common carotid artery and the left middle cerebral artery just distal to the olfactory tract for 1 h. We evaluated cerebral infarct volumes by TTC staining at 24 h after reperfusion, and performed immunohistochemical analysis for ORAIP.
Results: Compared with vehicle pre-treatment group (132 ± 42 [mean ± SD] mm3, n = 9), cerebral infarct volumes in mAb pre-treatment groups (0.5 and 1.5 mg/kg) were significantly decreased (82 ± 36 mm3, n = 10, P > 0.05 and 44 ± 37 mm3, n = 9, P < 0.001, respectively) in a dose-dependent manner. Furthermore, mAb post-treatment group (0.5 mg/kg) also showed a significant decrease (72 ± 39 mm3, n = 8, P < 0.05) in infarct volumes compared with vehicle post-treatment group (139 ± 48 mm3, n = 8). We found the expression of ORAIP in various types of neural cells in the ischemic penumbra region after cerebral I/R.
Conclusions: These data strongly suggest that ORAIP plays a pivotal role in cellular response to the oxidative stress and will be a critical therapeutic target for cerebral I/R injury.
PS02-014
Poster Viewing Session II
Enhanced neuroprotective effects against ischemic brain injury by intranasal delivery of granulocyte colony-stimulating factor in rats
and B. Sun1
1Key Lab of Cerebral Microcirculation in Universities of Shandong, Taishan Medical University, Neurology, Taian, China
Abstract
Objectives: Granulocyte colony-stimulating factor (G-CSF) is a hematopoietic growth factor with strong neuroprotective properties. However, it has limited capacity to cross the blood-brain barrier and thus potentially limiting its protective capacity. Recent studies demonstrated that intranasal drug administration is a promising way in delivering neuroprotective agents to the central nervous system. The current study therefore aimed at determining whether intranasal administration of G-CSF increases its delivery to the brain and its neuroprotective effect against ischemic brain injury.
Methods: Transient focal cerebral ischemia in rat was induced with middle cerebral artery occlusion.
Results: Our resulted showed that intranasal administration is 8–12 times more effective than subcutaneous injection in delivering G-CSF to cerebrospinal fluid and brain parenchyma. Intranasal delivery enhanced the protective effects of G-CSF against ischemic injury in rats, indicated by decreased infarct volume and increased recovery of neurological function. The neuroprotective mechanisms of G-CSF involved enhanced upregulation of HO-1 and reduced calcium overload following ischemia. Intranasal G-CSF application also promoted angiogenesis and neurogenesis following brain ischemia.
Conclusions: G-CSF is a legitimate neuroprotective agent and intranasal administration of G-CSF is more effective in delivery and neuroprotection and could be a practical approach in clinic.
PS02-015
Poster Viewing Session II
DSePA antagonizes high glucose-induced neurotoxicity: evidences for ROS-mediated oxidative damage and MAPKs and AKT pathways
and C. Fan1
1Taishan Medical University, Taian, China
Abstract
Objectives: Hyperglycemia as the major hallmark of diabetic neuropathy severely limited its therapeutic efficiency. Selenium (Se) an essential trace element is of fundamental importance to humans due to its multiple pharmacological properties. Increasing evidences also indicate that Se supplement can effectively reduce the risk of neurological diseases. In the present study, 3, 3′-diselenodipropionic acid (DSePA), a derivative of selenocystine, was employed to investigate its protective effective against high glucose-induced neurotoxicity in PC12 cells and evaluate the underlying mechanism.
Methods: Several methods of cell biology and molecular biology in vitro were employed.
Results: The results suggested that high glucose (100 mM) treatment for 48 h induced mitochondria-mediated apoptosis in PC12 cells, accompanied by poly (ADP-ribose) polymerase (PARP) cleavage, caspase activation, depletion of mitochondrial membrane potential (Δψm). Moreover, high glucose treatment also resulted in DNA damage and dysregulation of MAPKs and AKT pathways through triggering intracellular reactive oxygen species (ROS) overproduction. p53 RNA interference partially suppressed high glucose-induced cytotoxicity and apoptosis. Addition of four chemical inhibitors of MAPKs and AKT pathways further confirmed that MAPKs and AKT pathways both contributed to high glucose-induced neurotoxicity. However, DSePA pre-treatment for 6 h effectively attenuated high glucose-induced cytotoxicity, inhibited the loss of Δψm through regulation of Bcl-2 family expression, and ultimately reversed high glucose-induced apoptotic cell death in PC12 cells. Attenuation of caspase activation, PARP cleavage, DNA damage, and accumulation of ROS all confirmed its protective effects. Moreover, DSePA markedly alleviated the dysregulation of the MAPK and AKT pathways induced by high glucose.
Conclusions: Our findings revealed that the strategy of using DSePA could be a highly effective way in prevention or therapy of diabetic neuropathy.
PS02-016
Poster Viewing Session II
Pharmacological inhibition of monoacylglycerol lipase reduces ischemic brain injury
S.-H. Choi1, Y. Mou1, J. Hallenbeck1 and A.C. Silva1
1NINDS/NIH, Bethesda, United States
Abstract
Monoacylglycerol lipase (MAGL) hydrolyzes the endocannabinoid 2-arachidonoylglycerol and thus terminates endocannabinoid signaling, which regulates production of arachidonic acid and prostaglandins that mediate inflammatory response. Here, we have studied both the effects of the selective MAGL inhibitors JZL184 and MJN110 on experimental models of focal cerebral ischemia, as well as the underlying molecular mechanisms and receptors involved. The sensorimotor cortex of spontaneously hypertensive rats (SHR) and their normotensive controls the Wistar-Kyoto (WKY) rats was lesioned either by intracortical microinjection of endothelin-1, a potent vasoconstrictor peptide, or by a permanent transection of a branch of the middle cerebral artery. Either one of the selective MAGL inhibitors JZL184 or MJN110 was administered 60 min after focal cerebral ischemia. Infarct volumes, hemispheric swelling, and functional outcomes were assessed between days 1–28 by magnetic resonance imaging, histology, and behavioral tests. Pharmacological inhibition of MAGL significantly attenuated infarct volume and hemispheric swelling. MAGL inhibition also ameliorated sensorimotor deficits, suppressed inflammatory response, and decreased the number of degenerating neurons. These beneficial effects of MAGL inhibition were not fully abrogated by the selective antagonists of cannabinoid receptors, indicating that the anti-inflammatory effects are rather caused by reduced prostaglandin synthesis than by activation of cannabinoid receptors. Our results suggest that MAGL may contribute to the neuropathology of focal cerebral ischemia and thus is a promising therapeutic target for the treatment of ischemic stroke.
PS02-017
Poster Viewing Session II
Cyanidin attenuates tumor chemotherapy-induced neurotoxicity via inhibition of ROS-mediated DNA damage and apoptosis in PC12 cells
and X. Fu1
1School of Basic Medicine, Taishan Medical University, Neurology, Taian, China
Abstract
Objectives: Cisplatin-based chemotherapy in clinic is severly limited by its adverse effect, including neurotoxicity. Oxidative damage contributes to cisplatin-induced neurotoxicity, but the mechanism remains unclearly. Cyanidin a natural flavonoid compound exhibits powerful antioxidant activity. Hence, we investigated the protective effects of cyanidin on PC-12 cells against cisplatin-induced neurotoxicity and explored the underlying mechanisms.
Methods: MTT assay, flow cytometry analysis, TUNEL-DAPI co-staining, caspase activity, detection of ROS accumulation and western blotting assay were all employed to detect the protective mechanism.
Results: The results showed that cisplatin-induced cytotoxicity was completely reversed by cyanidin through inhibition of PC-12 cell apoptosis, as proved by the attenuation of Sub-G1 peak, PARP cleavage and caspases-3 activation. Mechanistically, cyanidin significantly inhibited reactive oxygen species (ROS)-induced DNA damage in cisplatin-treated PC-12 cells.
Conclusions: Our findings revealed that cyanidin as an apoptotic inhibitor effectively blocked cisplatin-induced neurotoxicity through inhibition of ROS-mediated DNA damage and apoptosis, predicating its therapeutic potential in prevention of chemotherapy-induced neurotoxicity.
PS02-018
Poster Viewing Session II
Molecular H2 alleviates perinatal asphyxia-induced elevations in neuronal COX-2 expression
V. Varga1, O. Oláh2, J. Németh1, V. Tóth-Szüki1, A. Lehóczki1, G. Remzső1, V. Kovács1, F. and and Domoki1
1University of Szeged, Department of Physiology, Szeged, Hungary
2University of Szeged, Department of Pathology, Szeged, Hungary
Abstract
Aim: Hypoxic-ischemic encephalopathy (HIE) occurs as a complication of perinatal asphyxia (PA). Cyclooxygenase-2 (COX-2) is the major constitutively expressed isoenzyme in the brain and plays an important role in neuronal damage. COX-2 was previously shown to be induced by cerebral ischemia but not by PA, therefore, our aim was to test if PA would induce neuronal COX-2 expression, and if COX-2 levels were affected by neuroprotective H2-treatment.
Methods: Newborn piglets (n = 47) were anaesthetised, artificially ventilated and intensively monitored. PA was elicited either by 8 min trachea-occlusion or by 20 min ventilation with hypoxic-hypercapnic gas mixture (6% O2-20% CO2) to induce moderate and severe HIE, respectively. H2-treatment was performed after both PA by reventilation with 2,1% H2 in air for 4h, also appropriate time control groups and naïve animals were included. After 24 hours of survival, the brains were harvested, processed, and the percentage of COX-2 immunopositive neurons were determined in cortical and subcortical areas.
Results: Neuropathology showed significant neuronal damage after PA that was alleviated by H2. Only the more severe PA elicited region-specific significant elevations in neuronal COX-2 expression, COX-2 was increased in the parietal and occipital cortex, as well as in the CA3 hippocampal area. High percentage (>50%) of COX-2 immunopositive neurons were always associated with the most severe neuropathology. H2-treatment reduced COX-2 immunopositivity to the level of time controls. Notably, COX-2 immunopositivity was markedly decreased in time controls compared to the naïve animals.
Conclusion: Translationally relevant PA has been demonstrated to elevate neuronal COX-2 expression for the first time in piglets. PA-induced COX-2 increases may play region-specific role in the progress of neuronal lesion during HIE. The alleviation of COX-2 expression may contribute to the neuroprotective effect of H2. Neuronal COX-2 levels appear to be reduced by 24h analgesia/anaesthesia that may explain some of the beneficial effects of supportive HIE therapy.
PS02-019
Poster Viewing Session II
The effects of preconditioning on the long-term cognitive dysfunction after sevoflurane exposure in neonatal rats
and T. Goyagi1
1Akita University Graduate School of Medicine, Department of Anesthesia and Intensive Care Medicine, Akita-City, Japan
Abstract
Objectives: Anesthetic exposure induces neural apoptosis and degeneration in developing neonatal brain. Preconditioning (PC) with isoflurane and hypoxia can reduce neural injury in anesthetized rodents. We examined whether PC with sevoflurane or hypoxia attenuated long-term neural degeneration in neonatal rats exposed to 3% sevoflurane (Sevo).
Methods: Six-day-old (P6) Wistar rats were divided into 4 groups: control, PC (Sevo), PC (O2) and PC (-). PC consisted of exposure to a predetermined gas in two 1 h cycles separated by a 30 min interval with air. The control group was exposed to a carrier gas (30% oxygen) on P6 and then again on P7 for 4 h. The PC (Sevo) group, PC (O2) group and PC (-) group were preconditioned with 2% Sevo, 10% oxygen, or the carrier gas respectively, and then exposed to 3% Sevo for 4 h on P7. To assess cognitive function, the eight-arm radial maze was conducted on P46-P49, and the fear conditioning test was conducted on P42 and P49. Hippocampus was stained with NeuN on P49 to observe histopathological changes. Data (mean ± SD) were analyzed using one-way and two-way ANOVA, and differences were considered statistically significant at p < 0.05.
Results: The total time to visit all 8 arms in PC (-) rats was significantly longer than in PC (O2) and control rats on P46 and P47. PC (O2) rats made significantly more working errors than the PC (-) and PC (Sevo) rats on P47. The PC (-) rats made fewer correct choices than rats in the other groups. There was no significant difference in freezing time. PC (O2) rats had more NeuN positive cells in the CA1 than PC (-) rats.
Conclusions: PC with 2% Sevo or 10% oxygen would attenuate long-term cognitive dysfunction induced by exposure to 3% Sevo for 4 h in neonatal rats.
PS02-020
Poster Viewing Session II
Minimally invasive surgery joint local cooling lavage protects rats brain from ICH-induced inflammation injury and apoptosis
and X. Fu1
1School of Basic Medicine, Taishan Medical University, Neurology, Taian, China
Abstract
Objectives: Hypothermia treatment is one of the neuroprotective strategies that improve neurological outcomes effectively after brain damage. Minimally invasive surgery (MIS) has been a more and more important treatment of intracerebral hemorrhage (ICH). Herein we evaluated the neuroprotective effect and mechanism of MIS joint local cooling lavage (LCL) treatment on intracerebral hemorrhage (ICH) via detecting the inflammatory responses, oxidative injury and neuronal apoptosis around the hematoma cavity in rats.
Methods: ICH model was established by type IV collagenase caudatum infusion. The rats were treated with MIS 6 h after injection then were lavaged by normothermic (37 centigrade) and hypothermic (33 centigrade) normal saline (NS) in brain separately.
Results: The results showed that the MIS joint LCL treatment significantly suppressed IHC-induced inflammation injury and apoptosis in Rats, as convinced by the decline of active-caspase-3 and TUNEL-positive cells, followed by the decrese of IL-1beta and LDH and increase of IL-10 and SOD.
Conclusions: This study demonstrated that the strategy of using MIS joint LCL may achieve enhanced neuroprotection against ICH-induced inflammation injury and apoptosis in Rats with potential clinic application.
PS02-021
Poster Viewing Session II
ONO-5046 attenuation of delayed motor neuron death and effect on the induction of 78 kDa glucose-regulated proteinafter spinal cord ischemia in rabbits
T. Suzuki1, M. Sakurai1, H. Suzuki1 and T. Kawamura1
1Sendai Medical Center, Sendai, Japan
Abstract
Motor neurons are vulnerable to spinal cord ischemia. Neutrophil activation is thought to contribute to ischemia-reperfusion injury in the spinal cord. Thus, we investigated whether ONO-5046, a specific inhibitor of neutrophil elastase, could protect against ischemic spinal cord damage.
We used a rabbit spinal cord ischemia model in which a transient 15-minute period of ischemia was induced using a balloon catheter. Saline or ONO-5046 (5mg/ml in saline) was administered intravenously from the induction of ischemia until after 60 minutes of reperfusion. Neurological symptoms were assessed at, 8 hours and 1, 2,and 7 days post-ischemic insult. Rabbits were euthanized at these four time points, and spinal cords were dissected and preserved for histological analyses. Cell damage was analyzed in hematoxylin-eosin stained-sections by counting the number of surviving motor neurons and assessing histological changes. Based on our preliminary findings in ischemic spinal cord, immunocytochemical studies were performed for glucose-regulated protein (GRP)78, caspase12, and eukaryotic initiation factor 2α (elf2α).
ONO-5046 eased the functional deficits and increased motor neuron survival after ischemia. The induction of GRP78 was significantly prolonged by ONO-5046 treatment, whereas the expression of caspase 12 was reduced. Elf2α was not observed at any time point.
This study indicates that ONO-5046 may protect motor neurons from ischemic injury by prolonging GRP78 expression and reducing the expression of pro-apoptotic caspase 12. These results suggest that ONO-5046 might be used as a therapeutic agent in the treatment of ischemic spinal cord injury.
Reference
Fujita S, Sakurai M, Baba H, Abe K, Tominaga R. Autophagy-mediated stress response in motor neurons after hypothermic spinal cord ischemia in rabbits. J Vasc Surg. 2014; 62: 1312–1319.
PS02-022
Poster Viewing Session II
Effects of NMDA receptor antagonist memantine on NO production, hydroxyl radical metabolism and ischemic change of hippocampal CA1 during cerebral ischemia and reperfusion in mice
Y. Ito1, A. Tanaka1, K. Kawasaki1, C. Kitabayashi1, M. Yamazato1, R. Nishioka1, M. Hirayama1, K. Takahashi1 and N. Araki1
1Saitama Medical University, Neurology, Saitama, Japan
Abstract
Introduction: The purpose of this study is to investigate the nitric oxide production, hydroxyl radical metabolism and ischemic change of hippocampal CA1 during cerebral ischemia and reperfusion in mice.
Methods: (1) C57BL/6 mice [n = 15] were used. Memantine 25 µmol/kg was given in 5 mice 30 minutes before ischemia, and others were contol group. Both NO production and hydroxyl radical metabolism were continuously monitored by in vivo microdialysis. Microdialysis probes were inserted into the bilateral striatum. The in vivo salicylate trapping method was applied for monitoring hydroxyl radical formation via 2,3 dihydroxybenzoic acid (DHBA). A Laser doppler probe was placed on the skull surface. Forebrain cerebral ischemia was produced by occlusion of both common carotid arteries for 10 minutes. Levels of NO metabolites, nitrite (NO2-) and nitrate (NO3-), in the dialysate were determined using the Griess reaction. (2) 8-OHdG immunopositive cell: To evaluate to oxidative stress in Hippocampal CA1 neurons, the ratio of the number of 8-OHdG immunopositive cell was calculated in 72 hours after the start of reperfusion.
Results: (1) Blood pressure and Cerebral blood flow (CBF): There were no significant differences between the groups. (2) NO2-; Memantine group (120.9 ± 5.0%; mean ± SD) showed significantly higher than that of the control group (88.5 ± 18.0) after repurfusion 60 minutes (p< 0.05). (3) NO3-; Memantine group (97.2 ± 10.1) showed significantly higher than that of the control group (65.3 ± 21.0) at ischemia (p< 0.05). (4) 2,3-DHBA; Memantine group (89.1 ± 4.0) showed significantly lower than that of the control group (102.6 ± 11.5) at ischemia (p< 0.05). (5) 8-OHdG immunopositive cell: Memantine group (8.5 ± 8.6%) showed significantly lower than that of the control group (47.6 ± 30.6) (p< 0.01).
Conclusion: These in vivo data suggest that memantine effects on NO and hydroxyl radical metabolites in mice, and may have neuroprotective effect against cerebral ischemic injury.
PS02-023
Poster Viewing Session II
Exercise intensity affects peripheral immunity in the absence of IL-10
K. Poinsatte1, U.M. Selvaraj1, S.B. Ortega1, X. Kong1, A. McPartlin1, E.J. Plautz1 and A.M. Stowe1
1UT Southwestern Medical Center, Neurology and Neurotherapeutics, Dallas, United States
Abstract
Objectives: Our previous research found that exercise intensity has a dose-dependent effect on splenic B cell populations, particularly regulatory B cells (Bregs), in outbred mice after stroke. We wanted to examine if exercise-induced immunomodulation of Bregs was altered in the absence of IL-10.
Methods: Male 8–12 week-old C57BL/6 (WT) and IL-10-/-/C57BL/6 mice underwent 3 weeks of voluntary exercise training with sedentary controls (n = 8–13 mice/group). A 60-min transient middle cerebral artery occlusion was induced. Infarct volumes and post-stroke peripheral inflammation was analyzed using flow cytometry at 1-day post-stroke.
Results: IL-10-/- mice ran at a lower intensity than WT mice (p = 0.008). Overall, there was no significant neuroprotective effect of exercise on infarct volumes between strains, though 5/13 IL-10-/- mice did not exhibit any discernible infarct volume. IL-10-/- mice with larger infarcts had a greater number of B cells (p = 0.0007), Bregs (p = 0.008), innate-like B cells (B1a; p = 0.002), and conventional B cells (B2; p = 0.008) in the spleen post-stroke. Correlation analysis of exercise intensity showed a dose-dependent, non-linear effect on infarct volumes and splenic B cells subsets in IL-10-/- mice. IL-10 -/- mice that ran at high and low intensities had larger infarct volumes than mice that exercised at moderate intensities (R2 = 0.710). Moderately exercising IL10-/- mice exhibited reduced populations of B cells (R2 = 0.769) Bregs (R2 = 0.862), and B1a cells (R2 = 0.878) in the spleen. In contrast to our previous findings in outbred mice, there was no relationship between voluntary exercise intensity and B cells subsets in WT mice.
Conclusion: Exercise-induce modulation of peripheral B cell subsets following stroke is strain dependent, with moderate exercise reducing infarct volumes and suppressing B cell populations in the spleen in IL-10 KO mice, but not WT controls. Future studies should determine mechanisms that suppress proliferation, or potentially promote egress of B cells into the injured CNS, in the absence of IL-10.
PS02-024
Poster Viewing Session II
New generation progestins are neuroprotective in experimental stroke
M. El Amki1, P. Baumgartner1, R. Steffen1, H. Schneider1, A.R. Luft1, M. Weller1, B. Imthurn2, G.S. Merki-Feld1 and S. Wegener1
1University Hospital Zurich, Department of Neurology, Zurich, Switzerland
2University Hospital Zurich, Department of Reproductive Endocrinology, Zurich, Switzerland
Abstract
Background: Progestins are synthetically produced steroid hormones derived from progesterone, predominantly used for contraception. Progesterone has been shown to exert neuroprotective effects in different disease models. Our goal was to test the effect of the new generation progestins desogestrel and drospirenone on infarct size and behavioural deficits in experimental stroke.
Methods: Different groups of C57/Bl6 mice were used: (1) males, (2) female ovariectomized mice modeling postmenopausal females, and (3) female non-ovariectomized mice pretreated daily (10 days), as in females taking a contraceptive pill. Transient middle cerebral artery occlusion (MCAO) was performed to induce ischemic stroke. Following MCAO, progestin, vehicle or progesterone (positive control) were administered at 1, 6 and 24 h post-ischemia. Deficits were assessed using the sticky tape test and a composite neurological score and infarct size by triphenyl tetrazolium chloride (TTC) staining at day 3.
Results: Stroke size and neurological deficits were significantly less after treatment with both progestins compared to controls (sesame oil). The effect was most pronounced in males, intermediate in female ovariectomized and least pronounced in female non-ovariectomized mice. Based on evidence of altered GABAA receptor mediated tonic inhibition by neurosteroids, the expression of GABAA receptor subunits after progestin treatment is currently analyzed as one candidate mechanism of this effect.
Conclusions: New generation progestins are neuroprotective in experimental stroke, in male as well as female individuals. Our data support that these agents, already in clinical use, may be promising candidates for stroke applications.
PS02-025
Poster Viewing Session II
Impaired hypoxic tolerance in APP23 mice: a dysregulation in neuroprotective globin levels
Z.P. Van Acker1, E. Luyckx1, W. Van Leuven1, E. Geuens1, P.P. De Deyn2,3, D. Van Dam2,3 and S. Dewilde1
1University of Antwerp, Laboratory of Protein Science, Proteomics and Epigenetic Signalling, Wilrijk, Belgium
2University of Antwerp, Laboratory of Neurochemistry & Behaviour, Wilrijk, Belgium
3University of Groningen, Alzheimer Research Centre, Groningen, Netherlands
Abstract
Objectives: Neuroglobin is a neuronal expressed heme protein of the globin family which takes part in cytoprotection. In particular its ability to scavenge and detoxify reactive oxygen species has received much interest. Moreover, transgenic overexpression of neuroglobin reduces β-amyloid formation and the aggregation-associated neurotoxicity. Nonetheless, neuroglobin transcription is only triggered up to moderately advanced Alzheimer's disease (AD). As later stage AD is characterized by a lowered oxygen availability due to cerebral amyloid angiopathy, we questioned whether hypoxia as a secondary insult could have a similar neuroglobin-expression downregulating effect in young APP23 mice. Furthermore, while functions of another globin -cytoglobin- entail neuroprotection as well, its involvement in the AD pathology remained to be elucidated.
Methods: In this study we utilized RT-qPCR and immunohistochemistry analyses to examine globin levels in the normoxic and hypoxic murine brain. Both wild-type and APP23 mice were studied at 3, 6 and 12 months of age.
Results: Cortical cytoglobin levels parallel the increase of neuroglobin in 12-months-old APP23 mice. In addition, we identified a decreased expression of both globins in APP23 brains when subjected to whole-body hypoxia. The latter implies a key role for cerebral hypoperfusion in the loss of these neuroprotective globins in the later stages of the AD pathology. To further unravel the underlying mechanism, we studied RE-1-silencing transcription factor (REST/NRSF) expression levels, of which we identified a recognition site in the regulatory region of both globins. Neuroglobin-cytoglobin-REST expression correlations were detected mainly in the cortex.
Conclusions: This study is the first to indicate a possible widening of the endogenous neuroprotective actions of cytoglobin to the β-amyloid pathology. As for upstream regulation, we hypothesize REST/NRSF activation patterns to contribute to globin expression alterations.
References
T.Burmester and T. Hankeln, Acta Physiol (Oxf), 211 (2014) 501–514.
A.A. Khan et al., PNAS, 104 (2007) 19114–19119.
PS02-026
Poster Viewing Session II
Variation of blood injection velocity in a new experimental model of non-aneurysmal SAH: any influence on intracranial pressure and cerebral perfusion in the acute phase?
C. Conzen1, K. Becker2, W. Albanna1, H. Clusmann1, A. Höllig1, U. Lindauer2 and G.A. Schubert1
1RWTH Aachen University, Department of Neurosurgery, Aachen, Germany
2RWTH Aachen University, Translational Neurosurgery and Neurobiology, Aachen, Germany
Abstract
Introduction: Aneurysmal subarachnoid hemorrhage (aSAH) is hallmarked by rapid increase of intracranial pressure (ICP) and acute hypoperfusion contributing to early brain injury.
Non-aneurysmal SAH (naSAH) is assumed to result in less dramatic ICP changes and possibly preserved cerebral perfusion with a better neurological outcome. This study aimed to develop an experimental model of naSAH by variation of injection velocity in order to determine the role of ICP on acute changes after SAH.
Method: SAH in rats was induced by cisternal injection of 0.5 ml arterial blood (AB) or 0.5ml normal saline (NS) in predefined time frames: group AB1 0.5 ml/1 min (n = 8), AB10 0.5 ml/10 min (n = 11), AB30 0.5 ml/30 min (n = 7), NS1 0.5 ml/1 min (n = 9), NS10 0.5 ml/10 min (n = 10). Cortical blood flow (CBF), intracranial pressure (ICP) and mean arterial blood pressure (mABP) were recorded for 6 h after SAH.
Results: Maximum increase of ICP was highest in AB1 (p< 0.001). AB groups showed a significantly higher ICP throughout the observation period (plateau phase >1 h post SAH, p< 0.001). MABP increased significantly in AB1 compared to AB10 and AB30 (p< 0.001). NS injection had no effect on mABP.
CBF decreased significantly in AB groups compared to baseline pre-SAH (AB1 p< 0.001, AB10p< 0.001, AB30 p< 0.01). Maximum decrease was reached at different time points (AB1: 1 min, AB10: 9 min, AB30: 70 min post SAH). After 35 min, there was no significant difference detectable between the AB groups. Significant hypoperfusion was observed for 112 min in AB1, 165 min in AB10 and 90 min in AB30 compared to baseline.
Discussion: Higher velocity of blood injection is associated with a higher increase of ICP, but changes do not extend beyond the hyperacute phase. Acute hypoperfusion is observed at all blood injection velocities, but not with saline injection. Variation of injection velocity may facilitate investigation of different SAH entities and their respective acute and chronic stages.
PS02-027
Poster Viewing Session II
Differential expression of microRNA in of rat cerebral arteries during organ culture and after experimental subarachnoid hemorrhage
S.T. Christensen1, S.E. Johansson1 and L. Edvinsson1
1Rigshospitalet, Glostrup, Glostrup Research Institute, Department of Clinical Experimental Research, Glostrup, Denmark
Abstract
Objective: The objective was to study microRNA (miRNA/miR) changes in rat cerebral arteries using organ culture, serving as a model for optimization of miRNA inhibition assays, and after subarachnoid hemorrhage (SAH).
Organ culture of cerebral arteries has previously been applied as a method mimicking events occurring in the vasculature after experimental SAH. Both methods revealed activation of the mitogen-activated protein kinase (MAPK) signaling pathway, leading to increased expression of contractile receptors in vascular smooth muscle cells (VSMCs) [1].
We hypothesize that by inhibiting potential miRNAs during organ culture and in SAH, we could inhibit the receptor upregulation and thereby alleviating the delayed cerebral ischemia (DCI) that may occur after SAH leading to death and disability. This approach may more specifically affect targets in the event chain, putatively providing a powerful treatment strategy.
Methods: Basilar- and middle cerebral arteries were dissected from Sprague Dawley rats, cleaned and cultured in DMEM for 0, 6, 12, 24 or 48 hours. Changes in miR-143 and miR-145 levels were evaluated by qPCR using the 2-ΔΔCt quantitative method and statistically calculated using a non-parametric Mann-Whitney t-test. Experimental SAH was done according to previous protocol [2].
Results: A 1,7-fold increase of miR-145 was observed after 6 hours in organ culture, while no significant increase was observed for miR-143. Previous analysis of 900 microRNAs in cerebral vessels revealed that only miRNA-143 and miR-30a showed increased expression [2]. Validation of miR-143 and miR-145 levels at 6 hours after experimental SAH is ongoing.
Conclusions: Organ culture might exhibit differences in miRNA expression compared to what has previously seen after experimental SAH. Identifying the molecular mechanisms of SAH specific miRNAs could be important for treatment of DCI.
2. Muller, A.H., et al., BMC Genomics, 2015. 16: p.119.
PS02-028
Poster Viewing Session II
Anti-vasospastic effects of epidermal growth factor receptor inhibitor in experimental subarachnoid hemorrhage model
F. Nakano1, S. Pak1, F. Kawakita1, L. Liu1, Y. Nakatsuka1, H. Nishikawa1, T. Okada1, M. Terashima1, M. Shiba1 and H. Suzuki1
1Mie University, Department of Neurosurgery, Tsu, Mie, Japan
Abstract
Objectives: Aneurysmal subarachnoid hemorrhage (SAH) is a devastating disease. After treatment of aneurysms patients may still suffer from cerebral vasospasm. Tenascin-C (TNC) is one of epidermal growth factor receptor (EGFR) ligands. We reported that in healthy animals, vasoconstriction was induced by recombinant TNC administration and was reversed by using an EGFR inhibitor1. In this study, we investigated whether EGFR inhibitors prevent cerebral vasospasm and sought the involved signaling pathways in a mice SAH model.
Methods: Mice underwent endovascular perforation SAH modeling or sham-operation as previously described2. At 0.5h after surgery, mice received vehicle or drug (EGFR inhibitor, AG1478 or cetuximab) intra-ventricularly. At 24h after surgery, mice were sacrificed. Vasospasm was measured using Lumen Radius/Wall Thickness ratio (LRWT) as previously described3.
Results: The SAH-vehicle group showed severe vasospasm (P< 0.01, vs sham-vehicle) and deteriorated neurological score (P< 0.01). There was a significant improvement in vasospasm (P< 0.01, vs SAH-vehicle) and neurological score (P< 0.05) observed in the SAH-drug group. In Western blotting, phosphorylated extracellular-regulated kinase 1/2 (p-ERK 1/2), which has been considered as a vasospasm-related molecule, was highly expressed in the SAH-vehicle group (P< 0.05, vs sham-vehicle) and was suppressed in the SAH-drug group (P< 0.05, vs SAH-vehicle).
The SAH-cetuximab group also showed improvement in neurological score (P = 0.07, vs SAH-vehicle) and LRWT (P< 0.05).
Conclusions: Two kinds of EGFR inhibitors showed improvement in neurological score and vasospasm after SAH in mice. EGFR is thus supposed to involve in cerebral vasospasm development and p-ERK 1/2 may act as one of the signaling molecules downstream of EGFR. More study is needed for unveiling mechanisms of cerebral vasospasm after SAH in more detail.
References
1. Fujimoto M, et al. Brain Res. 2016
2. Suzuki H, et al. Stroke. 2010
3. Sabri M, et al. J Cereb Blood Flow Metab. 2011
PS02-029
Poster Viewing Session II
Intracranial pressure elevation is delayed following intracerebral hemorrhage in rats
K.E. Warren1,2, D.J. Beard1,2,3, R.J. Hood1,2 and N.J. Spratt1,2,4
1University of Newcastle, Callaghan, Australia
2Hunter Medical Research Institute, Newcastle, Australia
3University of Oxford, Oxford, United Kingdom
4John Hunter Hospital, Neurology, Newcastle, Australia
Abstract
Objectives: Elevated intracranial pressure (ICP) is a potential complication that can increase the already high morbidity and mortality rates associated with intracerebral hemorrhage (ICH). Elevated ICP has previously been attributed to the presence of cerebral edema. Our studies in rat experimental ischemic stroke found that ICP rose significantly 24 hours after small strokes with minimal edema. Early short-duration hypothermia prevented this rise. Our aim was to determine whether a similar ICP rise occurs after experimental ICH.
Method: ICH was induced in 8 male Wistar rats using the striatal collagenase infusion model. Occurrence of spontaneous intraventricular hemorrhage (IVH; n = 3) was recorded to permit separate subgroup analysis. Controls received saline infusion (n = 2). ICP was recorded from baseline to 3h and from 20–28 h post-infusion then animals were sacrificed for histological edema volume calculation.
Results: ICP did not differ between groups at baseline, or during the infusion or 3 h thereafter. ICP rose significantly from baseline in ICH animals (Δ9.27 ± 6.57 mmHg; p< 0.01). Peak ICP occurred at average 24.4 ± 1.7 h post-infusion. Baseline-Peak ICP was not significantly raised in controls (Δ4.38 ± 1.84 mmHg; p > 0.05). ICP rose significantly in ICH subgroups with and without IVH. However peak ICP in ICH+IVH animals was significantly greater than in those without IVH (23.44 ± 6.42 v 11.27 ± 3.28; p< 0.01). Edema volumes in ICH animals were modest (23.5 ± 17.3 mm3) and not significantly different between subgroups or from control.
Conclusions: ICP rose significantly 24 hours after experimental ICH and was higher in animals with ventricular hemorrhage. Edema volumes were modest and not significantly different between groups. This may indicate that ICP rise after ICH occurs by a mechanism similar to that in ischemic stroke and may be prevented by early short-duration hypothermia.
PS02-030
Poster Viewing Session II
Reduced cerebral microperfusion early after experimental subarachnoid hemorrhage
K. Nehrkorn1 and N. Plesnila1,2
1Institute for Stroke and Dementia Research, Munich, Germany
2Munich Cluster for Systems Neurology (SyNergy), Munich, Germany
Abstract
Subarachnoid hemorrhage (SAH) is a subtype of stroke associated with high mortality due to cerebral ischemia that develops within 12 hours after the bleeding. Early cerebral ischemia may be caused by pearl sting like constrictions of pial arterioles as observed in patients and mice subjected to SAH. Since the consequence of these pial microvasospasms for tissue perfusion is still unclear, we investigated the parenchymal microcirculation following SAH.
C57BL/6 mice were subjected to experimental SAH as previously described (Schüller et al., 2015) and the pial and parenchymal cerebral microcirculation was visualized in vivo 3 hours after SAH by 2-photon microscopy. In order to be able to distinguish microvascular perfusion before and after SAH animals received a red plasma dye before and a green plasma dye after SAH.
Beside the previously described pearl sting like constrictions the direct comparison of the same vessel segments before and after SAH allowed us to identify two new constriction patterns: global filamentous constrictions and local constrictions with a bottleneck shape. These constrictions resulted in a reduced blood flow velocity in pial arterioles as compared to sham surgery. Pial venules were not constricted. Within the cortical parenchyma the volume of perfused microvessels decreased by ∼80% after SAH.
Taken together our results suggest that pial arterioles constrict within the first few hours after SAH due to contact with subarachnoid blood. The constriction pattern is not uniform but comprises bottle-neck- and pearl-string-like as well as filamentous microvasospasms. Constrictions of the pial arterioles are associated with a massive loss of parenchymal perfusion. These data demonstrate that the ischemia observed early after SAH is mainly due to constrictions of pial arterioles resulting in severely impaired parenchymal microcirculation. Restoration of pial vessel diameter may therefore represent a promising target for the treatment of early ischemia after SAH.
PS02-031
Poster Viewing Session II
Are there factors within cerebrospinal fluid that cause intracranial pressure to rise after subarachnoid hemorrhage?
R.J. Hood1,2, D.D. McLeod1,2, K.E. Warren1,2, D. Pepperall1,2 and N.J. Spratt1,2,3
1University of Newcastle, Callaghan, Australia
2Hunter Medical Research Institute, New Lambton Heights, Australia
3John Hunter Hospital, Neurology, Newcastle, Australia
Abstract
Objective: Published data from our laboratory has showed that edema, the previously assumed mechanism for intracranial pressure (ICP) elevation in all disorders of acute neurological injury, is not the primary cause for ICP elevation 24 hours post-ischemic stroke in rats. Using our novel cerebrospinal fluid (CSF) transfusion assay we discovered that factors within CSF collected <6 hours post-stroke cause significant ICP elevation. Similarities in the pathophysiology of ischemic stroke and subarachnoid hemorrhage (SAH) led us to hypothesise that a similar mechanism may cause ICP elevation post-SAH. In this pilot study we assessed whether factors within post-SAH CSF cause ICP elevation.
Method: CSF (200 µL) collected from SAH patients (5–52 hours post-SAH; n = 4) and hydrocephalus (control) patients (n = 3) was infused into the left lateral ventricle of naive male recipient Wistar rats at 4 µL/min. ICP was measured from pre-infusion to 30 minutes post-infusion and again 16–24 hours post-infusion.
Results: ICP did not rise significantly during the first 30 minutes post-infusion. However during the later monitoring period it increased significantly from baseline in SAH-CSF recipients, peaking at ΔICP = 2.4 ± 1.5 mmHg (p = 0.04) at 20 ± 1 hours post-infusion. There was no significant difference between baseline and peak ICP in the control-CSF recipients (ΔICP 1.6 ± 2.5, p = 0.22). However, change in ICP from baseline to peak was not significantly different between groups (p = 0.69).
Conclusion: Our preliminary results suggest that factors may be present within CSF post-SAH that influence ICP. This was a modest rise compared with the previous CSF transfusion studies and may be explained by the broad range of CSF collection times post-SAH. This will be further investigated using CSF collected <6 hours post-SAH as in previous studies with ischemic stroke CSF.
PS02-032
Poster Viewing Session II
An MRI study on the neuroprotection of human albumin in subarachnoid hemorrhage
Y. Sun1, L. Watts2, G.-Y. Yang3, J. Suarez4 and T. Duong2
1Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Department of Functional Neurosurgery, Shanghai, China
2The University of Texas Health Science Center at San Antonio, Research Imaging Institute, San Antonio, United States
3Med-X Research Institute, Shanghai Jiao Tong University, Neuroscience and Neuroengineering Research Center, Shanghai, China
4Baylor College of Medicine, Baylor St Luke’s Medical Center, Department of Neurology, Houston, United States
Abstract
Objectives: Development of new treatments for subarachnoid hemorrhage (SAH) might prevent hemodynamic-related neurological complications and subsequently reduce the mortality. Human albumin has been demonstrated neuroprotective in various cerebrovascular diseases. However, very few studies investigate the effect of albumin therapy after SAH, especially through imaging approach. Hence, Magnetic resonance imaging (MRI) are utilized to longitudinal evaluate hemodynamic changes after albumin treatment underlying experimental SAH within the acute phase.
Methods: We used a multimodal approach by measuring cerebral blood flow (CBF), magnetic resonance angiography (MRA), and magnetic resonance venography (MRV) changes using an 11.7-T MRI scanner. Hypercapnic challenge functional MRI were acquired using typical parameters. Blood was injected into the cisterna magna of the rats to mimic SAH. Human albumin (1.25 g/kg) or same volume saline (5 ml/kg) are injected intravenously 30min after SAH establishment. Hemodynamic changes and neurological assessment were evaluated before, after SAH and within 7 days after treatment.
Results: 1) Dramatic declines of survival rates were observed after saline injection, indicative of severe adverse effects of volume expansion by saline. 2) Transient CBF increases in cortex after albumin injection suggests regional basal CBF improvement during the acute phase (p > 0.05). In contrast, hypercapnic challenge CBF response in the albumin group showed no significant differences from the control (p > 0.05). 3) While no diameter changes in the arteries were observed after albumin treatment across the time points (p> 0.05), vein dilation wasalleviated at 1 and 3 hrs following SAH compared to control animals (p< 0.05). 4) There was a trend that albumin group showed a better spontaneous recovery in the travel distance and foot-fault test compared to control animals throughout the first week.
Conclusions: These findings suggest that human albumin has potential protective effects on insulted hemodynamics which may contribute to acute complications after SAH.
PS02-033
Poster Viewing Session II
Stent salvage for coil protrusion of ruptured intracranial aneurysm
1Korea University/Ansan Hospital, Neurosurgery, Ansan-si, Korea, Republic of
Abstract
Despite recent advances in technology, parent vessel coil herniation occasionally complicates successful coil embolization, particularly in wide-necked aneurysms. We report endovascular stent deployment specifically to treat this complication.
A 50-year old man underwent coil embolization of ruptured aneurysm at anterior communicating artery. Coil herniation into the parent vessel developed during procedure. Endovascular stent deployment was performed to isolate the herniated portion of the coil from the parent vessel lumen.
The occluded parent vessel was completely recanalized right after the deployment of stent. The patient recovered very well and follow-up angiography at 6 months demonstrated no aneurysm recanalization and no stenosis of the parent vessel in the stented region.
The use of intraluminal stents has been reported to be a helpful technical adjunct to the conventional endovascular treatment of aneurysms. One additional indication for the use of this technology is sequestering herniated coils from the lumen of the parent artery to reduce potential embolic or occlusive sequelae.
PS02-034
Poster Viewing Session II
Cytochrome P450 1B1 is a potential vital molecule inducing vascular smooth muscle cells of human brain arteriovenous malformation towards pathological phenotype
M. Yuanyuan1, S. Jianping2, Q. Meijie1, H. Jun3, W. Zhenyu4, S. Yaying1, L. Peixi2, W. Yongting5, Z. Zhijun5, Z. Wei2 and Y. Guo-Yuan5
1Ruijin Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
2Huashan Hospital of Fudan University, Shanghai, China
3Shanghai Institute Of Hypertension, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
4Shanghai Ninth People’s Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
5Med-X Research Institute and School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China
Abstract
Objectives: Brain arteriovenous malformation (BAVM) has a high disbility rate due to hemorrhage in young adults. The molecular mechanism for the occurrence and development of BAVM is unknown. Current study found that smooth muscle cells phenotype transformation plays an important role in the development of vascular diseases1. Our previous proteinomic results showed that Cytochrome P450 1B1 (CYP1B1) was highly expressed in cultured human BAVM vascular smooth muscle cells. However, whether the CYP1B1 is involved in the development of BAVM is unclear. We aimed to explore the role of CYP1B1 in the phenotype transformation of vascular smooth muscle cells derived from BAVM.
Methods: Human BAVM vascular smooth muscle cells were cultured from fresh specimen via explant culture. Immunostaining, qRT-PCR, western blot and CCK-8 assay were performed to identify vascular smooth muscle cells and determine phenotype transformation related gene expression and proliferation ability in human BAVM vessels and cultured smooth muscle cells, respectively.
Results: We demonstrated that the cultured vascular smooth muscle cells derived from BAVM were a-SMA and MYH11 positive. These cells showed a higher proliferation ability compared to the normal control (P< 0.05). CYP1B1 was highly expressed in BAVM specimen and vascular smooth muscle cells compared to the control (P< 0.05). It was noted that vascular smooth muscle cells phenotype transformation related genes a-SMA, CNN1, and SM-22a were weakly expressed in vessels and vascular smooth muscle cells of BAVM compared to the control (P< 0.05).
Conclusion: BAVM vascular smooth muscle cells display CYP1B1 higer expression, which is associated with higher proliferation and lower phenotype transformation related gene expression, suggesting that CYP1B1 is a potential vital molecule inducing human BAVM vascular smooth muscle cells towards pathological phenotype.
Reference
1. MicroRNA-663 regulates human vascular smooth muscle cell phenotypic switch and vascular neointimal formation. Li P et al. Circ Res. 2013;113(10):1117–27.
PS02-035
Poster Viewing Session II
A systemic drive of IL-1β after intracerebral haemorrhage
J. Barrington1, A. Parry-Jones1, S.M. Allan1 and D. Brough1
1University of Manchester, Faculty of Biology, Medicine & Health, Manchester, United Kingdom
Abstract
Objectives: Spontaneous non-traumatic intracerebral haemorrhage (ICH) accounts for around 12% of stroke cases worldwide. Roughly 40% of ICH cases prove fatal and, of those that survive, less than 40% live independently at 12 months. The parenchymal ingress of blood constituents leads to a progressive secondary injury linked to the onset of inflammation through increased interleukin 1 signalling (IL-1). Whilst IL-1 inhibition has proven effective in preclinical stroke models and is promising in clinical trials, there are currently no reliable ways to monitor plasma levels of IL-1 cytokines. We set out to quantify IL-1β levels in haemorrhagic stroke patient plasma.
Methods: Blood samples were taken between 4 and 28 days of acute ICH from patients with different aetiologies. Plasma samples were clarified and incubated with capture antibody conjugated to magnetic particles. IL-1β protein was labelled with a fluorescent detection antibody and eluted from beads before being quantified using the ultrasensitive Erenna Immunoassay System.
Results: Plasma IL-1β was detectable in all patients (0.56–1.53 pg/mL) and sat below the limit of detection for traditional protein quantitation methods. Data herein show IL-1β levels increased 2-fold between study entry and a second timepoint 7–14 days later.
Conclusions: Using single molecule counting technology, we have identified a systemic upregulation of IL-1β up to 14 days post-ictus in haemorrhagic stroke patients. Thus indicating IL-1β signalling could be an important facet in acute stroke damage and post-stroke sequelae. Focus will now turn toward preclinical investigations into the underlying inflammatory processes propagating IL-1β signalling, with a key point of interest being the inflammasome complexes.
PS02-036
Poster Viewing Session II
Evaluating cerebral blood flow and metabolism in subarachnoid hemorrhage patients in the neurointensive care unit using MR-based imaging
H.S. Mangat1, J. Cho2,3, P.E. Stieg4 and Y. Wang2,3
1Weill Cornell Medical College, Neurology, New York, United States
2Cornell University, Biomedical Engineering, New York, United States
3Weill Cornell Medical College, Radiology, New York, United States
4Weill Cornell Medical College, Neurological Surgery, New York, United States
Abstract
Subarachnoid hemorrhage (SAH) causes high morbidity and mortality. 50% of patients suffer cerebral vasospasm and 30% cerebral ischemia and infarction. PET studies have shown cerebral blood flow (CBF)-metabolism uncoupling after SAH. However, PET cannot be routinely performed for acute brain injury patients. Here we investigated MR based CBF and metabolism measurement as an alternative method.
3D multi-echo gradient echo and arterial spin labeling (ASL) imaging were performed and cerebral rate of metabolism for oxygen (CMrO2) and oxygen extraction fraction (OEF) determined using Minimum Local Variance method utilizing QSM and CBF. Regions of interest (ROIs) were marked in each lobe.
Four neurologically intact patients underwent MRI on average 8.5 days after SAH. Mean Hunt Hess Grade was 2; modified Fisher grade 3. No patient had angiographic vasospasm.
Overall grey matter (GM) CBF was 55.52 ± 1.93 ml/100 g/min and in white matter (WM) 44.62 ± 3.58 ml/100 g/min; GM CMrO2 was 139.25 ± 7.88 µmol/100g/min and WM CMrO2 was 108.75 ± 20.72 µmol/100 g/min; GM OEF was 33.5 ± 2.3% and WM OEF 32.75 ± 3.8%. Mean GM CBF was 55.9 ml/100 g/min in frontal, 57.0 in parietal, 52.7 in temporal and 56.5 in occipital lobes; and in WM 40.19 ml/100g/min in frontal lobe, 43.6 in parietal, 46.5 in temporal and 48.3 in occipital lobe. GM CMrO2 was 131 µmol/100g/min in frontal, 138 in parietal, 150 in temporal, 138 in occipital lobes; WM CMrO2 was 92 µmol/100g/min in frontal, 91 in parietal, 133 in temporal and 119 in occipital lobes. GM OEF was 32% in frontal, 32% in parietal, 37% in temporal, 33% in occipital lobes; WM OEF was 31% in frontal, 29% in parietal, 38% in temporal and 33% in occipital lobes.
Our results are consistent with published PET data on regional CBF, CMrO2 and OEF. MR based measurement of cerebral metabolism is feasible and safe, appears reliable and has a large potential for utilization in acute brain injury patients in the neurointensive care unit.
PS02-037
Poster Viewing Session II
Relationship between gyrus rectus resection and cognitive impairment after surgery for ruptured anterior communicating artery aneurysms
and C.T. Moon1
1Konkuk University Medical Center, Neurosurgery, Seoul, Korea, Republic of
Abstract
Objective: The gyrus rectus (GR) is known as a non-functional gyrus; hence, its resection is agreed to be a safe procedure frequently practiced to achieve a better surgical view during specific surgeries. This study aimed at comparing the cognitive outcomes following GR resection in patients who underwent surgery for ruptured anterior communicating artery (ACoA) aneurysms.
Methods: From 2012 to 2015, 39 patients underwent surgical clipping for ruptured ACoA aneurysms. Mini-mental state examinations (MMSE) were performed in 2 different periods. The statistical relationship between GR resection and MMSE results was evaluated, and further analysis of MMSE subgroup was performed.
Results: Twenty-five out of the 39 patients (64.19%) underwent GR resection. Mean initial and final MMSE scores in the GR resection group were 16.3 ± 9.8 and 20.8 ± 7.3, respectively. In the non-resection group, the mean initial and final MMSE scores were 17.1 ± 8.6 and 21.9 ± 4.5, respectively. Neither group's scores showed a significant change. Subgroup analysis of initial MMSE showed a significant difference in memory recall and language (p = 0.02) but not in the final MMSE scores.
Conclusion: There was no significant relationship between the GR resection and cognitive outcomes in terms of total MMSE scores after surgery for ruptured ACoA aneurysm. However, subgroup analysis revealed a temporary negative effect of GR resection in the categories of language and memory recall. This study suggests that GR resection should be executed superficially, owing to its close anatomical relationship with the limbic system.
PS02-038
Poster Viewing Session II
Assessment of risk factors for the development of dementia of Alzheimer type
and M. Salohiddinov1
1Tashkent Medical Academy, Tashkent, Uzbekistan
Abstract
The urgency of the problems of dementia at old ageand in the first place - dementia of Alzheimer type (DAT), united now in the diagnostic category “Alzheimer's disease” (AD), has steadily increased. This is due to the frequency of AD/DAT, prolonged disabling disease course and large economic costs for treatment and care of patients who at an advanced stage of the disease Goal. To investigate risk factors for the development of asthma and protectors factors, presumably reducing the risk of disease.
Methods: Clinical-anamnestic study of 40 patients observed in the neurology department of TMA were held to study the effect on morbidity indicators of biological, constitutionally-personal and psychosocial (environmental) factors. The work was based on the assessment (by the standard questionnaire) of occurrence of family history or personal history of individuals included in the study, presumably for AD risk factors.
Results of the study: The results of our study suggest It was found that in the group of patients, widows were more common (p< 0.005) and significantly less (p< 0.005) living in married older people compared to age-matched individuals without mental disorders. According to the application, the method of statistical analysis significant factor-protector for DAT turned a history of acute and including frequent, stressful situations (respectively: CDF = 0.3; 95% CI 0,14–0,67 and CDF = 0.3; 95% CI 0,1–0,59). The value of the CDF smoking factor was on the borderline level of reliability as an RF (CDF = 0.3; 95% CI 0,05–1,17, P = 0.96).
Conclusions: This research shows us that the brain damaging effects of environmental factors increase the risk of DAT. and environmental factors involved in the mechanism of neuroprotection or activation in pathogenesis of the disease involved neurotransmitter systems, can obviously reduce the risk of disease.
PS02-039
Poster Viewing Session II
Low self-awareness of cognitive deficits is associated with regional hypometabolism in the default mode network
J. Therriault1, T. Pascoal2, K. Ng2, S. Mathotaarachchi2, P. Kang1, M. Shin2, N.P.V. Nair3 and P. Rosa-Neto2
1McGill Center for Studies in Aging, Neuroscience, Montreal, Canada
2McGill Center for Studies in Aging, Montreal, Canada
3McGill University/Douglas Institute, Montreal, Canada
Abstract
Objectives: This study aimed to test the hypothesis that low self-awareness of cognitive deficits in Mild Cognitive Impairment (MCI) subjects is associated with regional glucose hypometabolism in neural structures implicated in self-referential processing.1,2
Methods: Using data from the Alzheimer's Disease Neuroimaging Initiative (ADNI), we defined low self awareness based on the differences between subjects and caregiver global ratings on the Everyday Cognition (E-Cog) questionnaire. The cutoff as the threshold for low self-awareness was then calculated using the best operational point on the receiver operating characteristic (ROC) curve contrasting controls (n = 579) and AD subjects (n = 295). This cut off then stratified 732 MCI subjects into high and low self-awareness groups. A voxel-based regression model then compared the brain metabolism measured by [18F]fluorodeoxyglucose (FDG) positron emission tomography (PET) between the groups.
Results: Here, we demonstrated that a difference in global ECog scores between subjects and caregiver greater than −1 could reliably distinguish AD patients from healthy controls with 84% sensitivity and 84% specificity. Furthermore, we show that MCI individuals with low self-awareness demonstrated lower glucose metabolism in the basal forebrain, posterior cingulate cortex, dorsomedial prefrontal cortex and bilateral hippocampi compared to those with intact self-awareness.
Regional Differences in Glucose Hypometabolism Between High and Low Self-awareness Groups
Conclusion: Low self-awareness is associated with glucose hypometabolism in brain regions within the brain's default mode network (DMN) implicated in self-referential processing.
References
1Andrews-Hanna, J. R., Reidler, J. S., Sepulcre, J., Poulin, R., & Buckner, R. L. (2010). Functional-anatomic fractionation of the brain's default network. Neuron, 65(4), 550–562.
2Raichle, M. E. (2015). The brain's default mode network. Annual review of neuroscience, 38, 433–447.
PS02-040
Poster Viewing Session II
In vivo brain imaging for studying possible linkage between pathological hallmark of tauopathy and neuronal loss
H. Takuwa1, A. Ishikawa1, T. Urushihata1, T. Minamihisamatsu1, M. Tokunaga1, M. Shimojo1, S. Uchida1, I. Matsumoto1, M.-R. Zhang1, T. Suhara1, M. Higuchi1 and N. Sahara1
1National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, Chiba, Japan
Abstract
Accumulation of intracellular neurofibrillary tangles (NFTs) consisting of microtubule-associated protein tau is a major hallmark of tauopathy. Recently, a PBB3 ligand that selectively binding to tau inclusions was developed for the diagnosis of tauopathy. This ligand is useful for both positron emission tomography (PET) imaging and fluorescence imaging. Taking advantage of this multimodality of the PBB3 ligand, in vivo monitoring of NFT formation has been examined using tauopathy mouse model rTg4510 mice. This model typically exhibits forebrain atrophy and intraneuronal tau accumulation by 6 months of age. In this study, we performed in vivo two-photon microscopic imaging to investigate the progression of tau pathology at the cellular level. Fixation of a chronic cranial window to the skull enabled longitudinal monitoring for two months. In parallel, volumetric magnetic resonance imaging and [11C]PBB3-PET were conducted for the diagnoses of neurodegeneration. PBB3-positive inclusions were visualized with two-photon imaging as early as 4 months of age, while forebrain atrophy and [11C]PBB3 signal became noticeable at 6 months of age. The PBB3 signals from both PET and two-photon imaging reached a plateau at 6 months of age. Interestingly, although two-photon imaging revealed that PBB3-positive inclusions were continuously produced, subpopulations of the PBB3-positive inclusions disappeared within a few weeks. These results suggest that there is a rapid turnover of PBB3-positive inclusions. The rates of generation and disappearance were significantly reduced by the suppression of human P301L tau indicating that regulating human P301L tau expression enables the turnover to be controlled. In addition, disappearance rate of neurons with PBB3-positive inclusions was higher that that of neurons without PBB3-positive inclusions. These results suggest a strong association between PBB3-positive tau inclusions and neuronal death. In vivo multiscale imaging techniques could be useful tools to elucidate mechanisms of tau-induced neurotoxicity and to develop therapeutic interventions in tauopathy.
PS02-041
Poster Viewing Session II
In vivo tau distribution in progressive nonfluent aphasia
K.-M. Lee1, Y. Noh2, C.W. Yoon3, S.-Y. Lee4, N. Okamura5 and T. Ido4
1Seoul National University Hospital, Neurology, Seoul, Korea, Republic of
2Gachon University Gil Medical Center, Incheon, Korea, Republic of
3Inha University School of Medicine, Neurology, Incheon, Korea, Republic of
4Gachon University, Incheon, Korea, Republic of
5Tohoku University School of Medicine, Sendai, Japan
Abstract
Objective: Progressive nonfluent aphasia (PNFA) is the nonfluent/agrammatic variant of primary progressive aphasia. Underlying pathology of PNFA is heterogeneous, however, the major neuropathology of sporadic PNFA is known as taupathy. Recently several radiotracers for tau imaging have been developed for the in vivo visualization of tau pathology. In this study, the selective tau tracer [18F]-THK5351 was used to assess tau distribution in patients with clinically diagnosed PNFA.
Methods: Three PNFA patients (all male, aged 73–82, disease duration 12–36 months) and 34 cognitively normal controls (NC) were included in the study. All participants underwent [18F]-THK5351 PET scans, 3D magnetic resonance imaging (MRI), and detailed neuropsychological tests. To compare the distribution of tau deposition between two groups (PNFA and NC), voxel-based statistical analyses and regions of interest (ROI)-based statistical analyses were performed.
Results: Voxel-wise analyses of THK PET scans showed higher levels of THK retention in the left inferior frontal gyrus including Broca's areas, left medial frontal gyrus, left middle frontal gyrus and left ligual gyrus in patients with PNFA compared to NC. The median regional SUVR in the left inferior frontal area was higher in PNFA patients compared to NC [1.50 (1.41–1.51) vs. 1.36 (1.28–1.49)], however, it was not statistically significant.
Conclusions: The patients with PNFA showed elevated retention of [18F]THK5351 inferior frontal areas. These findings suggest that [18F]THK5351 PET could be used as a biomarker to assist in the diagnosis of PNFA.
PS02-042
Poster Viewing Session II
Diabetes-related increase of reactive α-dicarbonyls in the development of vascular dementia
S. Schultz1, A. Othman1 and M. Schwaninger1
1University of Lübeck, Institute for Experimental and Clinical Pharmacology and Toxicology, Lübeck, Germany
Abstract
Diabetes mellitus is the most common metabolic disorder in humans, approaching epidemic proportions with increasing incidence and prevalence over the last decades. Besides well described long-term complications like nephro-, neuro- and retinopathy, chronic hyperglycemia additionally displays a strong correlation with the development of dementia (Biessels et. al., 2006). Although it is well established that chronic hyperglycemia leads to vascular complications and cerebral microinfarcts, the molecular basis of the development of cognitive impairment due to diabetes is still unclear. A possible link between the increased blood sugar and the degenerating vascular system could be the production of highly reactive and toxic metabolites of glucose (Rabbani and Thornalley, 2015). Hence, we investigated the production of a distinct class of such molecules, which share an α-dicarbonyl structure, and their effect on the cerebrovascular system and cognitive decline.
Diabetes was induced in C57BL/6 mice by injecting 50 mg/kg streptocotocin on 5 consecutive days. After 12 weeks, mice were tested for cognitive impairment by an object-place recognition test. Afterwards mice were sacrificed for staining of the vascular system and detection of α-dicarbonyls by mass spectrometry.
We provide evidence that chronic hyperglycemia leads to an increase of α-dicarbonyls in blood plasma and brain tissue of diabetic mice. This result was associated with an increase of 4-hydroxynonenal positive vessels, indicating oxidative stress. Further analysis of the vascular system revealed higher abundance of string vessels, reflecting the degeneration of the vascular integrity. Furthermore, we detected an increase extravasation of IgG into the brain, which is a sign for disruption of the blood-brain barrier after long-term diabetes. Additionally, these mice showed signs of cognitive impairment while performing in an object-place recognition test.
Our data indicate that vascular pathology, associated with α-dicarbonyl-induced oxidative stress, could be an essential factor promoting cognitive impairment and dementia in diabetes patients.
PS02-043
Poster Viewing Session II
Investigating genetic factors contributing to vascular cognitive impairment in a mouse model recapitulating acute and chronic cerebral hypoperfusion
C. Sassi1, K. Bentele2, P. Böhm-Sturm3, F. Yildirim4, S. Mueller4, T. Farr5, M. Foddis4, C. Harms4 and U. Dirnagl4
5School of Life Sciences, University of Nottingham, Nottingham, United Kingdom
Abstract
Objectives: Vascular cognitive impairment is a complex disorder. Although genetic causes have been reported for the rare Mendelian forms1,2, 3, genetic risk factors underpinning the common sporadic cases have been understudied. To explore the contribution of genes to vascular cognitive decline we have investigated the transcriptomic changes in the frontal-subcortical memory circuit (prefrontal cortex, hippocampus and striatum) in a mouse model recapitulating the clinical features of acute and chronic cerebral hypoperfusion.4
Methods: Naïve male C57/BL6 mice (6 weeks) randomly received 160 µm (n = 4, coil) or 500 µm (n = 4, sham) internal diameter microcoils around both common carotid arteries. Cerebral blood flow (CBF) and T2 weighted MRI were performed. RNA sequencing was carried out on prefrontal cortex, hippocampus and striatum during acute and chronic cerebral hypoperfusion (24 hours, 7 days and 6 months post-surgery, respectively). Transcriptome-wide gene expression and alternative splicing analysis were performed using edgeR and DEXSeq, respectively.
Results: During chronic hypoperfusion (6 months) the CBF in the coil mice partially recovered to baseline. No transcriptome-wide significant difference at the gene expression level between sham and coil mice were found. However, alternative splicing analysis showed a modest but significant differential exon usage (p-value< 0.05 and log2FC ≥ 0.1) for genes already critically associated to dementia (Chrm1, Epha4 and Apoe). Acute brain hypoxia transcriptome and vascular dementia patient genetic screening are being investigated.
Conclusion: Diverse transcriptomic signatures in response to different degrees of brain ischemia may significantly contribute to mild cognitive impairment and represent robust genetic targets for clinical intervention. Alternative splicing analysis is a sensitive and effective tool to investigate the earliest genetic factors fine-tuning a trait.
References
1. Joutel, A. et al. Nature (1996).
2. Hara, K. et al.N. Engl. J. Med. (2009).
3. Richards, A. et al.Nat. Genet. (2007).
4. Shibata, M. et al., Stroke J. Cereb. Circ. (2004).
PS02-044
Poster Viewing Session II
Protective role of brain endothelial Nemo in microvascular pathologies and vascular dementia
Y. Jiang1, J. Wenzel1, D. A. Ridder1, J. Ohnmacht1 and M. Schwaninger1
1Institute of Experimental and Clinical Pharmacology and Toxicology, Lübeck, Germany
Abstract
Inactivating mutations of the NF-κB essential modulator (NEMO) cause incontinentia pigmenti (IP) which manifests with severe neurological symptoms in humans (Smahi et al. 2000). Our previous work showed that a specific Nemo knock-out in mouse brain endothelium leads to a disturbed blood-brain barrier (BBB) and microvascular pathologies (Ridder et al., 2015). Herein, by introducing a long-term deficiency, we would like to further investigate the role of brain endothelial Nemo during the development of microvascular pathologies, and to establish a novel in vivo model for vascular dementia.
NemoFL;Slco1c1-CreERT2 mice were either intraperitoneally (i.p.) injected or orally treated with tamoxifen to induce the brain endothelium specific knock-out. The body weight of animals was monitored. BBB integrity was detected by IgG extravasation and microvascular pathologies were investigated histologically by staining for the markers CD31 (endothelium), collagen IV (basement membrane), active caspase 3 (apoptosis) and Ki-67 (proliferation). Running wheels were used for spontaneous locomotor activity. The object place recognition (OPR) test was used to investigate memory deficits.
Induced endothelial Nemo deletion by i.p. injection led to a decreased body weight and the activity in running wheels. However, those parameters recovered after several weeks, probably due to the induced angiogenesis that we have observed, suggesting i.p. treatment was not suitable for the long-term investigation. Specific deletion of Nemo in mouse brain endothelium chronically by oral tamoxifen resulted in a body weight loss, BBB disruption, endothelial cells death and microvessels rarefaction suggesting tamoxifen diet as a good substitute. In those long-term Nemo deficient mice, we observed an increase in dead microvessels, a higher brain weight as indicator of brain edema, and a poor performance in OPR test.
Long term deficiency of Nemo in mouse brain endothelium will cause BBB disruption and microvascular pathologies and lead to the development of brain edema and cognition impairment.
PS02-045
Poster Viewing Session II
Vascular risk factors in manifestation of Alzheimer's disease related neuropathological changes: First autopsy and genetic evidence from a South Asian ageing population
P. Wijesinghe1, S.K. Shankar2, T.C. Yasha2, Y.H. Suh3, H.W.M. Steinbusch4 and K.R. De Silva1
1University of Sri Jayewardenepura, Anatomy, Nugegoda, Sri Lanka
2National Institute of Mental Health & Neurosciences, Neuropathology, Bangalore, India
3Seoul National University, Pharmacology, Seoul, Korea, Republic of
Background: The relationship between Alzheimer's disease (AD) and cerebrovascular disease (CVD) is complex; they share multiple risk factors and overlap neuropathologically. South Asia represents one-fourth of the world total population and to the best of our knowledge, this is the first autopsy study that has intended to investigate vascular risk factors associated in determining the aetiology of sporadic AD.
Methods: Postmortem brain samples from 76 elderly Sri Lankans (≥50yrs) were used to study genetic polymorphisms [apolipoprotein E (APOE), angiotensin converting enzyme (ACE), methylenetetrahydrofolate reducatse (MTHFR C677T) and factor V Leiden (FVL G1691A)], degree of atherosclerosis of the circle of Willis (CW) and microscopic infarcts in deep white matters. Screening for neurodegenerative pathologies was carried out using histopathological/immunohistochemical techniques in 50 brains (≥60yrs).
Results: Increasing age was significantly and strongly associated with Braak stages ≥1 [odds ratio (OR) = 1∙3, 95% confidence interval (CI) = 1∙08–1∙57), cerebral amyloid angiopathy (CAA) grade ≥1 (1∙11, 1∙0–1∙23), white matter hyperintensities (1∙09, 1∙00–1∙19) and hippocampal cell loss in CA1 region (1∙18, 1∙06–1∙31). Besides age, APOE ɛ4 allele and Thal β−amyloid phase ≥1 (6∙76, 1∙37–33∙45), Braak stages III−VI (0∙02, 0∙0–0∙47); literacy and Braak stages IV−VI (0∙68, 0∙01–0∙83) were associated significantly with logistic regression adjusted for age, sex. With respect to CVD; atherosclerosis of the CW and APOE ɛ3/ɛ4 (4∙48, 1∙09–18∙44) and APOE ɛ3/ɛ2 genotypes (0∙03, 0∙00–00∙68), and history of hypertension (15∙06, 3∙27–69∙31); CAA and MTHFR T allele (10∙58, 1∙16–96∙22); microscopic infarcts and both history of diabetes (10∙8, 1∙29–90∙6) and illiteracy (0∙15, 0∙03–0∙71); were all associated significantly. The effects seen with other vascular risk factors i.e.: ACE and FVL polymorphisms, smoking and alcohol consumption were not statistically important in this study.
Conclusion: Our findings indicate that besides age, illiteracy and genes, other vascular risk factors were not associated in determining the aetilogy of sporadic AD in these populations.
PS02-046
Poster Viewing Session II
Sesamol reverse memory deficit and restore phosphoGSK3β decreased in hippocampus in intracerebroventricular streptozotocin (ICV-STZ) induced Alzheimer's disease model
M. Golechha1,2, J. Bhatia2, V. Parihar3 and D.S. Arya2
1Indian Institute of Public Health, Gandhinagar, India
2All India Institute of Medical Science, Pharmacology, New Delhi, India
3University of California, Department of Radiation Oncology, Irvine, United States
Abstract
The present study was undertaken to investigate the effect of post-training administration of sesamol, a bioflavonoid on memory functions, brain insulin receptors (IRs), acetylcholinesterase (AChE) activity and oxidative stress in ICV-STZ induced dementia in rats. In these same animals the phosphorylated GSK3β (pGSK3β) and total GSK3β levels were also determined.
Wistar rats received ICV-STZ application (3 mg/kg twice) and 2 weeks later short (STM) and Long term memories (LTM) were assessed in an autoshaping learning task. Animals were sacrificed immediately following the last autoshaping session, their brains removed and dissected. The enzymes and IR protein levels were measured in the hippocampus and prefrontal cortex (PFC) by western blotting. ICV-STZ treated rats showed a memory deficit and significantly decreased pGSK3β levels and significant decrease in IR protein level in both hippocampus and PFC, while total GSK3β did not change, in both the hippocampus and PFC. Memory impairment was reversed by sesamol (5 and 10 mg/kg, i.p.). The pGSK3β and IR protein levels were restored by sesamol in the hippocampus and PFC. Sesamol produced no changes in pGSK3β levels in neither the hippocampus nor PFC. Total GSK3β levels did not change with either drug.
Furthermore, ICV-STZ resulted into enhanced AChE activity in hippocampus and PFC which was normalized by sesamol. An increase in MDA level and decrease in GSH level were obtained in both hippocampus and PFC in STZ treated group, indicating state of oxidative stress, which was also attenuated by sesamol. Altogether these results show the beneficial effects of sesamol due different mechanisms of actions on memory impairment induced by ICV-STZ. The results suggest that besides the anticholinesterase and antioxidant activity, effect on brain IR, pGSK3β levels, a kinase key of signaling cascade of insulin receptor may also be an important factor for protective effect of sesamol against STZ induced dementia model.
PS02-047
Poster Viewing Session II
Rapamycin as a novel therapeutic for Alzheimer's disease: prevention assessed through neuroimaging
and D. Ma1
1University of Kentucky, Lexington, United States
Abstract
Alzheimer's disease (AD) is the sixth leading cause of death in the United States. Although AD research is bustling, a concrete and effective treatment has yet to be discovered. This study aimed to assess vascular magnetic resonance imaging (MRI) as an early detection method for AD, and to then test the potential of FDA-approved drug Rapamycin (Rapa) in treating pre-symptomatic AD. Rapa is capable of increasing lifespan in mammals and inhibiting unwanted cell mobility, such as cancer cell growth. This study is the first to connect Rapa's capabilities with AD. In order to analyze Rapa's efficacy, neuroimaging and behavioral tests were conducted on mice that carry the apolipoprotein E4 gene (APOE4), the strongest genetic risk factor for AD. Methodology included MRI, magnetic resonance spectroscopy (MRS), Blood-Brain Barrier (BBB) integrity and neuroinflammation determinations, Radial Arm Water Maze (RAWM), and Novel Object Recognition Test (NOR). These methods provided a comprehensive analysis of the subjects' neurological health and cognitive functions by providing insight on cerebral blood flow, brain metabolites, spatial memory, recognition memory, and neuroinflammation. With vascular MRI, defects were successfully detected in the pre-symptomatic AD mice, helping identify the presence of AD. Data strongly supported the initial hypothesis that with the introduction of Rapa, APOE4 mice will show improved cognition, memory, and neurological health. Cerebral blood flow and crucial brain metabolites were restored in Rapa mice; Rapa mice exhibited cogent memory in comparison to their counterparts in cognitive tests; Rapa reduced neuroinflammation–all with significance. Vascular MRI effectively pinpointed early AD while Rapa restored neurological health in mice at risk of AD. Thus, vascular neuroimaging is a promising early detection technique and Rapa holds high potential in preventing AD development.
PS02-048
Poster Viewing Session II
Insulin resistance in the development of social and cognitive disorders in Alzheimer's disease
Y. Komleva1, Y. Gorina1, O. Lopatina1, A. Chernykh2 and A. Salmina1
1Krasnoyarsk State Medical University named after Professor V. F. Voyno-Yasenetsky, Biochemistry, Krasnoyarsk, Russian Federation
2Krasnoyarsk State Medical University named after Professor V. F. Voyno-Yasenetsky, Research Institute of Pathophysiology and Molecular Medicine, Krasnoyarsk, Russian Federation
Abstract
Alzheimer's disease (AD) is neurodegenerative disease, characterized by progressive cognitive impairment, senile plaques and neurofibrillary tangles. The results of studies show the key role of insulin resistance in cognitive impairment [Moreira, 2013].
Insulin signaling impairment initiates signaling cascades responses (inhibition of PI3K), protein kinase B and activation GSK-3β, thereby causing tau hyperphosphorylation, beta oligomers accumulation and oxidative stress, which leads to mitochondrial dysfunction, neurodegeneration and apoptosis [Blázquez E, 2014].
The aim of this work is to study the molecular mechanisms of insulin signal transduction pathways that determine the contribution of local progression of insulin resistance in the social and cognitive decline in AD.
Material and methods: We used CD1 male mice, aged 4 months. The animal model of AD was induced by injections of beta-amyloid into CA1 area. [Li X. et al., 2011]. Behavioral tests (fear conditioning, open field, light-dark box, five-trial test), immunohistochemistry staining.
Results: We found extracellular expression of pro-inflammatory cytokine IL-1 on astrocytes in subgranular zone of the dentate gyrus. Thus statistically significant increase of IL-1+ cells were observed in animals with AD (1,71 ± 0,34) compared to the sham-operated mice (0,69 ± 0,24) (p< 0.05).
We observed a statistically significant increase in expression of HMGB-1(high mobility group box-1) on a GFAP+ cells in the subgranular zone of the dentate gyrus in mice after neurodegeneration (2,47 ± 0,41) (the relative number of immunopositive cells) compared to sham-operated mice (0,8 ± 0,26) (p = 0,001).
Conclusion: Increased IL-1 intensity may indicate an activation of the inflammatory process due to assembly and activation of intracellular inflammasome that implement caspase-1 mediated intracellular processing and secretion of pro-inflammatory cytokines (IL-1, IL-18, IL-33), and the release of HMGB1 into extracellular space by pyroptosis. Interleukins and HMGB1, leads to the formation of synaptic and cognitive dysfunction, thus promoting the development of neurodegeneration.
PS02-049
Poster Viewing Session II
Oligodendrocyte response to focal white matter ischemic injury is different in juvenile and adult mice
A. Dingman1,2, S. Hickey3, E. Gould3, R.J. Traystman2,4, W.B. Macklin3 and P.S. Herson2,4
1University of Colorado School of Medicine, Child Neurology, Denver, United States
2Neuronal Injury Program, Denver, United States
3University of Colorado School of Medicine, Developmental Biology, Denver, United States
4University of Colorado School of Medicine, Anesthesiology, Denver, United States
Abstract
Background: Prior research suggests that the cellular response to white matter (WM) ischemic injury is different at different ages. Our prior studies demonstrate oligodendrocyte(OL) resistance to ischemic injury in juvenile animals compared to adults. However, little is known about whether WM repair mechanisms differ between juveniles and adults. We utilized a model of focal ischemic WM injury to determine the OL response to focal WM ischemic injury in juvenile and adult mice.
Methods: Juvenile (p21–25) vs adult (2–3 months of age) mice underwent stereotaxic injection of the potent vasoconstrictor N5-(1-iminoethyhl)-L-Ornithine (LNIO) into the lateral corpus callosum. All cells of OL lineage, as well as mature OLs were counted at 3 days post-injury, and histology analysis performed 3 weeks post-injury.
Results: In the injured WM there was similar loss of mature oligodendrocytes (Olig2+/CC1+) in juveniles (contralateral 4.9×10−4 ± 3.3 × 10−5 cells/area, ipsilateral 1.5×10−4 ± 9.1×10−5 cells/area, n = 4 per group, p< 0.05) and adult mice (contralateral 4.7 × 10−4 ± 1.5 × 10−5 cells/area, ipsilateral 1.1 × 10−4 ± 4.5 × 10−5 cells/area n = 4 per group, p< 0.05). However, while in adults there was also a decrease in all oligodendrocyte (Olig2+) lineage cells (contralateral 7.0 × 10−4 ± 1.7 × 10−4 cells/area, ipsilateral 3.4 × 10−4 ± 7.4 × 10−5 cells/area, n = 4 per group, p< 0.05), there was no decrease in Olig2+ cells in juvenile animals (contralateral 6.8 × 10−4 ± 5.4 × 10−5 cells/area, Ipsilateral 5.4 × 10−4 ± 2.5 × 10−4 cells/area, n = 4 per group, p = 0.2). In contrast to equivalent injury observed in the acute phase (3 days), histological analysis at 3 weeks suggested smaller injury size in juveniles (110353 ± 60482 pixels2) compared to adults (270125 ± 190666 pixels2), consistent with enhanced recovery.
Conclusions: Although mature oligodendrocytes are similarly vulnerable to WM ischemia in juvenile animals, immature OLs may be relatively preserved or may have increased proliferative potential, which may result in greater remyelination.
PS02-050
Poster Viewing Session II
Cortical spreading depression-induced prolonged oligemia can cause ischemic lesions at hemodynamically vulnerable border zones
B. Dönmez-Demir1, M. Yemişci1,2, G. Uruk1, S. Kazmi3 and T. Dalkara1,2
1Hacettepe University, Institute of Neurological Sciences and Psychiatry, Ankara, Turkey
2Hacettepe University, Faculty of Medicine, Department of Neurology, Ankara, Turkey
3The University of Texas at Austin, Biomedical Engineering Department, Austin, United States
Abstract
Prolonged oligemia induced by cortical spreading depression (CSD) may potentially lead to ischemia at hemodynamically vulnerable watershed zones. We found that KCl-induced repetitive CSDs for one hour caused ischemic histological changes at the border zone between the middle and anterior cerebral arteries under isoflurane anesthesia in mice. We developed an algorithm to calculate the mean CBF change from baseline for each pixel imaged by laser speckle contrast (LSC) throughout one-hour recording period. The mean CBF change during recurrent CSDs was −24% in the medial border zone, whereas it was −16% in the lateral parietal area under isoflurane anesthesia (n = 6), demonstrating that the CSD-induced CBF response was significantly modified by perfusion pressure and region-dependent. Under ketamine/xylazine (n = 6), the CBF changes were −13% and −16% in the medial and lateral areas, respectively. The mean regional changes under the two anesthetics were significantly different (p< 0.05). Coronal sections at least 1.5 mm posterior to KCl application site were studied 2 weeks after repetitive CSDs. Sham controls (n = 5) did not show any histological abnormalities. However, we observed neuropilic swelling, degenerating neurons, swollen peri-neuronal astrocyte endfeet in a vertical column of cortical tissue around penetrating arteries (PAs) located at the frontal cortical watershed areas between ACA and MCA in 5 out of 9 mice anesthetized with isoflurane. The diameter of the ischemic column was 171 ± 19 µm (n = 5 mice), in agreement with the size of the capillary-free tissue oxygenated by passive diffusion from the PA in the mouse (Krogh's cylinder). We did not observe a similar watershed lesion in 6 mice subjected to multiple CSDs under ketamine/xylazine anesthesia or in another set of 6 mice subjected to a single CSD under isoflurane anesthesia. In conclusion, these data suggest that the CSD-induced prolonged oligemia has the potential to induce ischemic lesions in hemodynamically susceptible watershed areas.
PS02-051
Poster Viewing Session II
Hereditary versus sporadic cerebral small vessel disease: what makes the differences?
M.-F. Ritz1, N. Peters2 and P. Lyrer2
1University of Basel, Department of Biomedicine, Basel, Switzerland
Objectives: Cerebral small vessel diseases (SVD) are among the most frequent causes of strokes, intracerebral hemorrhage and a leading contributor of vascular cognitive impairment and dementia. The monogenic condition known as cerebral autosomal-dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is the most common cause of inheritable form of SVD. Despite the great social and economic burdens resulting from these conditions, little is know about the pathogenesis of CADASIL and sporadic SVD and how to treat the patients. We used gene expression microarray data obtained from brain white matter (WM) regions in order to compare the two diseases and find specific cellular and biological pathways affected at the molecular level.
Methods: We compared the gene expression in post-mortem brain specimen (frontal and occipital WM) dissected from 2 CADASIL and 5 sporadic SVD patients, using oligonucleotide-based microarray technology (Affymetrix® Genechips). Gene annotation and statistical analysis were performed using Partek® Genomics Suite. Genes with fold expression changes F> 1.2 in both directions, and False Discovery Rate below 0.05 were considered significantly differently expressed between both groups. Biological functions enriched with these up- and down-regulated genes were identified using DAVID® bioinformatics resources.
Results: Functional classification revealed cellular pathways differently affected in CADASIL versus sporadic SVD. The vascular compartment was more affected in CADASIL, with enhanced cytokine-related fibrosis, reduced oxidative phosphorylation switching to anaerobic glycolysis, and induction of programmed cell death (apoptosis).
Conclusions: Elucidating the differences in molecular events participating in the pathologies of CADASIL and sporadic SVD will certainly identify novel and specific therapeutic approaches.
PS02-052
Poster Viewing Session II
Transient BDNF introduction therapy against delayed neuronal death in hippocampal CA1 neurons using biocompatible nanomicellar mRNA carrier
Y. Fukushima1, H. Imai1, S. Uchida2, K. Itaka3, H. Nakatomi1, K. Kataoka4,5 and N. Saito1
1The University of Tokyo, Graduate School of Medicine, Department of Neurosurgery, Bunkyo-ku, Japan
2The University of Tokyo, Graduate School of Engineering, Department of Bioengineering, Bunkyo-ku, Japan
3The University of Tokyo, Graduate School of Medicine, Laboratory of Clinical Biotechnology, Bunkyo-ku, Japan
4Innovation Center of NanoMedicine (iCONM), Institute of Industrial Promotion, Kawasaki, Japan
5The University of Tokyo, Policy Alternatives Research Institute, Bunkyo-ku, Japan
Abstract
After transient ischemia and subsequent reperfusion, hippocampal CA1 pyramidal neurons exhibit delayed neuronal death (DND), a gradual cell death process taking around a week after ischemia. While the phenomenon discloses that rapid recanalization of occluded artery is insufficient to totally prevent neuronal death in ischemic lesion, introduction of a neuroprotective factor during a therapeutic time window before DND, is a reasonable approach to obtain clinical outcomes. Messenger (m)RNA delivery is a promising option to obtain sustainable protein expression during the period. Compared to conventional gene therapy using DNA, mRNA delivery has several advantages, such as no risk of insertion mutagenesis, and availability for non-dividing cells. Although in vivo delivery of exogenous mRNA was technically challenging due to the instability and immunogenicity of mRNA, we successfully overcome these problems by developing biocompatible nanomicellar mRNA carrier, achieving rapid and sustainable protein expression for several days in rodent brain. In this study, a rat model of DND, induced by transient global ischemia, was treated by intraventricular injection of brain derived neurotrophic factor (BDNF) mRNA, and therapeutic effect was evaluated by quantifying NeuN-positive surviving neurons. In the optimization of injection schedule, single injection on 2 days after ischemia (DAI) showed enhanced neuroprotective effects on CA1 neurons, compared that on 1 and 3DAI, when assessed on 6DAI. Although single injection was not sufficient for obtaining sustainable effect, only one week of BDNF expression by twice injection on 2 and 5DAI, was effective in preserving CA1 neurons even in chronic phase (13 and 20DAI). These results suggest that permanent treatment effects against DND can be obtained by transiently providing neuroprotective factors in a critical pathological phase, presumably first 10 days after ischemia. We believe that transient BDNF introduction therapy, based on mRNA delivery, is a promising approach to DND after ischemia and reperfusion.
PS02-053
Poster Viewing Session II
Reversal of beta-amyloid-induced neurotoxicity in PC12 cells by curcumin, the important role of ROS-mediated signaling and ERK pathway
and M. Yang1
1Taishan Medical University, Taian, China
Abstract
Objectives: Progressive accumulation of beta-amyloid (Aβ) will form the senile plaques, caused oxidative damage and neuronal cell death, which was accepted as the major pathological mechanism to the Alzheimer's disease (AD). Hence, inhibition of Aβ-induced oxidative damage and neuronal cell apoptosis by agents with potential antioxidant properities represents one of the most effective strategies in combating human AD. Curcumin (Cur) a natural extraction from curcuma longa has potential of pharmacological efficacy, including the benefit to antagonize Aβ-induced neurotoxicity. However, the molecular mechanism remains elusive. The present study aim to evaluate the protective effect of curcumin against Aβ-induced cytotoxicity and apoptosis in PC12 cells and investigate the underlying mechanism.
Methods: Several methods of cell biology and molecular biology in vitro were employed.
Results: The results showed that curcumin markedly reduced Aβ-induced cytotoxicity by inhibition of mitochondria-mediated apoptosis through regulation of Bcl-2 family. The PARP cleavage, caspases activation and ROS-mediated DNA damage induced by Aβ were all significantly blocked by curcumin. Moreover, regulation of p38MAPK and AKT pathways both contributed to this protective potency.
Conclusions: Our findings suggested that curcumin could effectively suppressed Aβ-induced cytotoxicity and apoptosis by inhibition of ROS-mediated oxidative damage and regulation of ERK pathway, which validated its therapeutic potential in chemoprevention and chemotherapy of Aβ-induced neurotoxicity.
PS02-054
Poster Viewing Session II
The role of pericyte-mediated HIF-1 in blood-brain barrier modulation and stroke outcome following transient cerebral ischemia
C.-C. Tsao1,2, N. Kachappilly1 and O. Ogunshola1,2
1University of Zurich, Institute of Veterinary Physiology, Zürich, Switzerland
2University of Zurich, Zurich Center of Integrative Human Physiology, Zürich, Switzerland
Abstract
Objectives: Ischemic stroke leads to increased BBB permeability and loss of brain homeostasis resulting in aggravating stroke progression and compromised functional recovery. Indeed, maintenance of BBB integrity to improve neuronal recovery is a potential strategy for stroke. Hypoxia inducible factor-1 (HIF-1), the major regulator of the hypoxic/ischemic response, is crucial for cells to adapt to stress. Our in vivo study indicated pericyte-targeted HIF-1 deletion prevents vascular permeability and improves barrier stability under hypoxia. Although this study highlighted the crucial role of HIF-1 in pericytes during O2 deprivation, the contribution of pericyte-mediated HIF-1 signaling to barrier integrity, stroke outcome and recovery during cerebral ischemia remains unknown.
Methods: We subjected inducible pericyte-targeted HIF-1α knockout mice to transient middle cerebral artery occlusion for 45 minutes using the intraluminal filament method followed by reperfusion for up to 14 days. Ischemic damage, BBB permeability, neurological scores as well as neurobehavioral tests (e.g. the ladder rung test and the corner test) were assessed.
Results: Our data showed HIF-1α deletion does not majorly contribute to infarct volume, brain edema and neurological scores at 24 and 72 hours reperfusion. Intriguingly, HIF-1α deletion increases brain shrinkage at 14 days reperfusion. Moreover, KO mice had significantly less IgG extravasation and Evans blue leakage compared to control mice at 72 hours reperfusion. In contrast, at 14 days reperfusion KO mice showed significantly more IgG extravasation. Furthermore, our preliminary data of corner test indicated KO mice tend to show more left turns after Day 7 post-tMCAo compared to control mice.
Conclusions: Thus, our data suggest pericyte-mediated HIF-1 signaling differentially modulates barrier integrity at 72 hours and 14 days post-tMCAo and altered barrier might correlate with stroke outcome during disease progression. Further studies are now being performed to understand the underlying mechanisms.
Supported by an SNF grant (31003A_150062) to O.O.
PS02-055
Poster Viewing Session II
Central nervous system (CNS) pharmacokinetic study (PK) of cefotaxime in healthy rats: comparison of cerebral spinal fluid (CSF) and extracellular fluid (ECF) concentrations
C. Dahyot-Fizelier1,2, B. Bourdois1, B. Giraud2, W. Couet1,3 and S. Marchand1,3
1University of Medicine and Pharmacology of Poitiers, INSERM U1070, Poitiers, France
2University Hospital of Poitiers, Intensive Care and Anesthesia Department, Poitiers, France
3University Hospital of Poitiers, Pharmacokinetic Laboratory, Poitiers, France
Abstract
CNS infections' treatment is difficult, partly due to limitation of antibiotics' penetration by brain barriers. In human, CNS concentrations are mostly measured in CSF, considered as a good surrogate for brain target site to determine dosing regimens1. Qualitative differences exist between blood-CSF-barrier (B-CSF-B) and blood-brain-barrier (BBB), which could explain differences between CSF and brain ECF concentrations. Cefotaxime, recommended in CNS infections, distributes differently in CSF and ECF in patients2,3. We studied in healthy rats cefotaxime distribution in CSF and ECF to explore brain barriers.
Methods: After ethic committee approval (2016071110003253), 2 groups of Male Sprague Dawley rats (GECF and GCSF, 309 g ± 12 g) were studied. Surgeries were performed under general anesthesia and PK succeeded to 150 mg/kg of cefotaxime. In GECF (10 rats), 9 ECF samples (striatum microdialysis probe) and 7 blood samples (femoral vein catheter) were collected over 170 min. Unbound plasma concentrations and probes recoveries were measured (mean = 21 ± 3%)4. In GCSF, 6 PK profiles with 6 points over 150 min were obtained (36 rats). CSF was taken from skull base citern and blood in intracardiac. Cefotaxime was assayed by LC-MS/MS and PK parameters obtained by a non comparmental analysis3.
Results: Cefotaxime total plasma PK were comparable in both goups. ECF concentrations were higher than in CSF. ECF and CSF to unbound plasma AUC ratios were 47.0 and 2.8%, respectively (figure).
Unbound plasma, ECF, CSF PK profiles
Conclusions: As in human, cefotaxime distribution in healthy rats is limited in CSF and ECF, and lower in CSF compare to ECF. Thus, CSF is not a good surrogate for all brain target sites and cefotaxime probably across B-CSF-B and BBB differently, consistent with the PK theory of efflux transporters.
References
1- Westerhout. JPS 2011.
2- Nau. AAC. 1993
3- Dahyot-Fizelier. AAC 2013.
4- Chenel. BJP 2004.
PS02-056
Poster Viewing Session II
M1 and M3 muscarinic receptors interplay mediates murine brain microvascular endothelium response to acetylcholine
B.M. Radu1, M. Radu2, A. Banciu1, M. Di Chio3, F. Merigo4, G. Tsenov4, D.D. Banciu1, C. Tognoli4, P. Kačer5, G. Bertini4 and P.F. Fabene4
1University of Bucharest, Department of Anatomy, Animal Physiology and Biophysics, Bucharest, Romania
2Horia Hulubei National Institute for Physics and Nuclear Engineering, Department of Life and Environmental Physics, Magurele, Romania
3University of Verona, Department of Public Health and Community Medicine, Verona, Italy
4University of Verona, Department of Neuroscience, Biomedicine and Movement Sciences, Verona, Italy
5University of Chemistry and Technology, Department of Organic Technology, Prague, Czech Republic
Abstract
Clinical and experimental studies indicated muscarinic acetylcholine receptors as potential pharmacological targets in neurological diseases. Of particular interest is the role of cholinergic receptors in modulating brain circulation, as it is known that ACh plays an important regulatory role at the level of brain microvascularisation. Although muscarinic receptors were described in human, bovine and rat cerebral microvasculature, a subtype characterisation in mouse brain endothelium is missing. Here we show by immunofluorescence, qRT-PCR, protein quantification and calcium imaging, that all five (M1-M5) receptors are functionallly expressed in mouse primary and immortalized brain microvascular endothelial cells. Acetylcholine activates calcium transients in brain endothelium by muscarinic, but not nicotinic receptors. The mRNA ranking fits the protein abundance for M2, M3, M4 and M5, while there is a mismatch for M1. Although M1 and M3 are the most abundant, only a fraction of M1 in the plasma membrane is functional. The functional expression of muscarinic receptors in mouse brain endothelium could be exploited in further translational studies, considering as pharmacological targets the M1 and M3 receptors.
PS02-057
Poster Viewing Session II
Cannabidiol-loaded lipid nanocapsules for glioma therapy across the blood-brain barrier: in vitro assays on human brain endothelial and glioma cell lines
J. Aparicio-Blanco1,2, D.K. Male2, I.A. Romero2 and A.I. Torres-Suarez1
1Complutense University, Madrid, Spain
2The Open University, Walton Hall, Milton Keynes, United Kingdom
Abstract
The rapidly evolving knowledge about tumour biochemistry would in principle enable new drug molecules to be designed as potential treatments. Nevertheless, malignant brain tumours remain nowadays untreatable due to the failure to expose the entire tumour to such therapeutics at pharmacologically meaningful concentrations. In this regard, nanomedicine poses an appealing platform for efficient brain drug delivery, since it may provide optimal drug availability, and, subsequently, fewer side-effects.
Since cannabinoids are increasingly regarded as potential anticancer agents devoid of the systemic side effects of conventional chemotherapy, our group has developed lipid nanocapsules loaded with cannabidiol, the major non-psychotropic cannabinoid, to enable intravenous cannabinoid delivery. These nanocarriers have been prepared in three different sizes (20, 50 and 80 nm) using the phase inversion technique and have been thoroughly characterized.
Moreover, in vitro assays have been conducted on the human brain endothelial cell line hCMEC/D3 and on the human glioblastoma cell line U-373 MG to screen the potential to cross the blood-brain barrier and to assess the antitumoral efficacy of these nanomedicines, respectively. The encapsulation of the fluorescent dye 3,3′-dioctadecyloxacarbocyanine perchlorate (DiO) in the lipid nanocapsules for tracking purposes evidenced the internalization of the nanocarriers into both cell lines. The role played by the particle size on the uptake pattern has likewise been explored. Importantly, lipid nanocapsules seem to enhance cannabidiol activity in vitro against the human brain tumour cell line.
Taken together, these preliminary results are encouraging to put these nanomedicines forward as adequate cannabinoid-carriers for the treatment of gliomas.
PS02-058
Poster Viewing Session II
Dynamic regulation of the blood-brain barrier by neural activity
R. Pulido1, R. Munji1, C. Quirk1, S. Leutgeb1 and R. Daneman1
1University of California, San Diego, La Jolla, United States
Abstract
Objective: The vasculature of the central nervous system (CNS) have unique properties in comparison to vasculature in the periphery. Brain endothelial cells, which form the walls of the cerebral vasculature, encompass these unique properties which each individually contribute to reducing overall transport of peripheral ions and molecules into the CNS and only permitting essential ones. Although the vascular blood flow is tightly coupled to neural activity, barrier properties have largely been studied in a static context.
Aim: My goal is determine how neural activity can dynamically regulate cerebral vascular properties on the molecular level and how these functional changes can reciprocally affect brain function.
Methods: We used transgenic mice to express Gq- or Gi-DREADDs to manipulate neural activity in 3 major neuronal populations: glutamatergic, GABAergic and dopaminergic. Then we used in vivo electrophysiology to determine the ideal dosage of CNO to administer for each mouse strain to achieve the largest change in neural activity without inducing seizures. Then we injected mutant mice and littermate controls with CNO, FACS-purified their brain endothelial cells and performed RNAseq on the cells' RNA.
Results: Transcriptomics of brain endothelial cells purified after 3 hours of heightened glutamatergic activity revealed 653 significantly upregulated genes and 458 significantly downregulated genes. Pathway analysis revealed an upregulation of cytoskeletal genes mainly associated with focal adhesion. It also revealed a trend of downregulation of genes associated with metabolism. There was also a change in solute transporter expression implying that neural activity induces changes in the vasculature to alter the chemical composition of the brain.
Conclusion: Excitatory neural activity induces functional molecular changes in cerebral vasculature that may reciprocally affect brain functions. Follow up genetic knockout experiments will elucidate functionality of these endothelial responses. It will also be interesting to compare and contrast how manipulating the different types of neural activity globally affect the cerebral vasculature.
PS02-059
Poster Viewing Session II
Interaction of thrombin and sphingosine-1-phosphate on blood-brain barrier function
L. Stolz1, R. Brunkhorst1 and K. Devraj2
1Goethe University Medical School, Department of Neurology, Frankfurt, Germany
2Goethe University Medical School, Edinger Institute of Neurology, Frankfurt, Germany
Abstract
Several neurological diseases, such as multiples sclerosis (MS) and stroke, are associated with the loss of blood-brain barrier (BBB) integrity, leading to the entry of endogenous substances and pathogens into the central nervous system (CNS). To protect the brain from neuroinflammation and neurodegeneration there is an urgent need to understand the regulation of the BBB function and the underlying signaling pathways in order to restore the BBB function.
Sphingosine-1-phosphate (S1P) signaling has been demonstrated to be a targetable pathway in autoimmune neuroinflammation leading to a successful oral therapeutic for MS. Although the direct function of S1P on the CNS is not yet known, there are reports of S1P influencing the BBB function, however the mechanisms and context are unclear. In contrast, proteases from the coagulation cascade have been proposed to mediate inflammatory reactions in MS. Since thrombin is also known to have permeability effects on the BBB, we aim to elucidate the possible interaction of S1P and thrombin on the BBB function.
Our first results with porcine brain microvascular endothelial cells (PBMECs) in transendothelial electrical resistance (TEER) experiments show a rescue effect of the thrombin mediated BBB opening upon S1P stimulation. In the current project we will analyze the effects of S1P and thrombin on permeability related proteins both via expression analysis and morphology analysis of the PBMECs. Junction associated molecules like VE-cadherin, claudin-5, and occluding will be stained and quantified via Western blotting. Analysis of the sphingolipid levels by lipid mass spectrometry will be performed. Furthermore, downstream thrombin and S1P signaling pathways will be analyzed in S1P1 signaling mice.
PS02-060
Poster Viewing Session II
Hyperglycemia increases resting intracellular calcium and ischemic factor-stimulated calcium responses in blood-brain barrier endothelial cells
N. Klug1 and M.E. O'Donnell1
1University of California, Davis, Physiology and Membrane Biology, Davis, United States
Abstract
Objectives: Cerebral edema is exacerbated in diabetic ischemic stroke through poorly understood mechanisms. We showed previously that blood-brain barrier (BBB) Na-K-Cl cotransport (NKCC) and Na/H exchange (NHE) are major contributors to edema formation in normoglycemic ischemic stroke, increasing secretion of Na, Cl and water from blood into brain across a still intact BBB in the early hours of stroke. We also showed that hyperglycemia exacerbates edema through increased expression of NKCC and NHE with a more robust ischemia-induced increase in transporter activities. Currently we are investigating the signaling pathways that underlie hyperglycemia effects on BBB Na transporters in order to identify additional therapeutic targets for diabetic ischemic stroke. NKCC and NHE activities of a variety of cell types can be stimulated by increases in intracellular calcium ([Ca]i) and hyperglycemia has been found to alter [Ca]i dynamics in several cell types, including non-brain endothelial cells. In the present study we investigated the effects of hyperglycemia on BBB endothelial cell resting [Ca]i and ischemic factor-induced changes in [Ca]i.
Methods: Cerebral microvascular endothelial cells (CMEC) were exposed for 24 hr to hyperglycemic (30mM glucose) or normoglycemic (5mM glucose) or to osmotic control media (5mM glucose + 25 mM mannitol) then loaded with 5 µM Cal-520-AM and imaged in the presence or absence of arginine vasopressin (AVP, 100 nM). Calcium levels were normalized to maximal non-saturated calcium signal following the addition of 8 µM ionomycin.
Results: CMEC in normoglycemic media exhibited oscillatory calcium transients over a stable baseline. However, CMEC exposed to hyperglycemic media exhibited oscillatory calcium transients on top of large excursions above baseline and also a larger more sustained [Ca]i increase in response to AVP.
Conclusions: Exposure of BBB endothelial cells to high glucose alters intracellular Ca dynamics, causing higher baseline [Ca]i and a more robust response to ischemic factors.
Supported by NINDS and American Heart Association
PS02-061
Poster Viewing Session II
Elucidation of the roles of oligodendrocyte precursor cells after stroke
N. Kishida1, T. Maki1, H. Kinoshita1, Y. Takagi2 and R. Takahashi1
1Kyoto University, Neurology, Kyoto, Japan
2Kyoto University, Neurosurgery, Kyoto, Japan
Abstract
Objectives: Stroke is the most leading cause of adult neurological disability worldwide. Among various cell types in the brain, oligodendrocyte precursor cells (OPCs) have been shown to play more diverse and crucial roles than previously recognized. In addition to a well-known role of reservoir for mature oligodendrocytes which form myelin sheaths, OPCs could regulate neuronal, glial and vascular systems in a direct and reciprocal fashion. However, the roles of reactive OPCs under ischemic conditions are largely unknown. Thus, our aim is to evaluate how OPCs contribute to neurovascular damage and remodeling after stroke.
Methods: A mouse stroke model was produced by transient middle cerebral artery occlusion (MCAO). Cerebral blood flow was monitored by laser speckle imaging. Immunohistochemistry was conducted to evaluate the behavior of OPCs at days 1, 3, 7, 14, and 28 after MCAO. Blood brain barrier (BBB) integrity was also examined by IgG staining and Evans blue permeability assay. RNA sequencing was performed to profile gene expression in reactive OPCs isolated at various time points after MCAO.
Results: On day 1 after the surgery, PDGFR-α-positive OPCs remarkably decreased. Beginning on day 3, OPCs were increasing, especially at perivascular area in the ischemic area, and continued to increase on days 7 and 14. Increased “perivascular” OPCs were located closely to endothelial cells and pericytes. BBB leakage and angiogenesis with CBF recovery were observed in parallel with increased OPCs. Reactive astrocytes surrounded the increased OPCs. Functional recovery and axonal remodeling were observed but the extent of regeneration was not complete. RNA sequencing showed dynamic phenotypic changes of reactive OPCs after MCAO.
Conclusions: Our data suggest that reactive OPCs actively participate in the damage and repair reactions of neuronal, glial, and vascular systems after stroke. The modification of “pathological” OPCs would lead to novel therapeutic approach for stroke.
PS02-062
Poster Viewing Session II
Effect of the inhibition of microglial activation on hypothalamic-pituitary-adrenal (HPA) axis during sepsis
L.H. Costa1, N. Santos-Junior1 and M.J. Rocha2
1University of Sao Paulo/Ribeirao Preto Medical School, Ribeirao Preto, Brazil
2University of Sao Paulo/School of Dentistry of Ribeirao Preto, Ribeirao Preto, Brazil
Abstract
Objectives: The objective of the present work was to evaluate the role of microglial activation on regulation of ACTH and corticosterone plasma levels of rats submitted to sepsis by cecal ligation and puncture.
Methods: Male Wistar rats (300–350 g) received an i.c.v. injection of minocycline (100µ g, 5 µl), an inhibitor of microglial activation, or vehicle (sterile water, 5 µl) 5 minutes before septic stimulus. Sepsis was induced by cecal ligation and puncture (CLP)- 10 punctures, 16G needle. Six and 24 hours after the surgery, the animals were decapitated and blood and hypothalamus were collected for hormonal and cytokines analysis.
Results: Sepsis induced a decrease in ACTH plasma levels at both timepoints, which was attenuated (6 h) or reverted (24 h) with minocycline administration. Corticosterone plasma levels were augmented during sepsis and at 24 hours after CLP the inhibition of microglial activation led to a further increase in the hormone levels. Additionally, minocycline reduced the production of IL-1β in the hypothalamus of septic rats.
Conclusions: CLP-induced sepsis caused a disruption in HPA axis regulation, which seems to be at least partially mediated by the activation of microglial cells.
References
1 Flierl, M. A. et al. Disturbances of the hypothalamic-pituitary- adrenal axis and plasma electrolytes during experimental sepsis. Ann Intensive Care, v. 1, p. 53, 2011.
2. Kanczkowski, W. et al. Hypothalamo-pituitary and immune-dependent adrenal regulation during systemic inflammation. Proc Natl Acad Sci U S A, v. 110, n. 36, p.14801–6, Sep 2013.
PS02-063
Poster Viewing Session II
Hemoglobin induces phenotype switching and resistance to hemin toxicity through Connexin 43 mediated regulation of YAP nuclear translocation in rat cortical astrocytes
Y. Yang1, Y. Sun1, J. Ren1, B. Wang1, Z. Zhong1, Z. Xie1, Q. Sun1 and L. Bian1
1Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Department of Neurosurgery, Shanghai, China
Abstract
Objectives: Astroglial activation elicited by hematoma and its decomposition products plays a critical role in neurological deterioration after intracerebral hemorrhage. Uncovering the phenotype changes and potential mechanisms of astroglial activation may help to relieve the secondary injury and improve the patients' outcome. In this in vitro study, we investigated the molecular mechanisms and events in astrocytes' response to hemoglobin exposure.
Methods: Purified cortical astrocytes were exposed to hemoglobin, then cell proliferation, phenotype changes and resistance to hemin toxicity were evaluated. The expression and association of Connexin 43 and YAP were also investigated to explore the mechanism.
Results: Astrocytes were responsive to hemoglobin stimulation, showing elevated IL-1β, IL-6 and TNF-α mRNA expression, increased proliferative ability, enhanced resistance to hemin toxicity and epithelial-mesenchymal transition. Additionally, Connexin 43 downregulation was observed to be accompanied with YAP nuclear translocation. YAP inhibitor partially counteracted the astrocytic response to hemoglobin exposure. Connexin 43 and YAP were physically associated as determined by co-immunoprecipitation.
Conclusions: Astrocytes underwent phenotype changes upon hemoglobin stimulation and acquired promoted proliferation and enhanced resistance to hemin toxicity. Connexin 43 mediated regulation of YAP nuclear translocation is involved in this process.
References
1. Macco R, Pelizzoni I, Consonni A, Vitali I, Giacalone G, Martinelli Boneschi F, et al. Astrocytes acquire resistance to iron-dependent oxidative stress upon proinflammatory activation. Journal of neuroinflammation. 2013;10:130.
2. Gram M, Sveinsdottir S, Ruscher K, Hansson SR, Cinthio M, Akerstrom B, et al. Hemoglobin induces inflammation after preterm intraventricular hemorrhage by methemoglobin formation. Journal of neuroinflammation. 2013;10:100
3. Yu FX, Zhao B, Guan KL. Hippo Pathway in Organ Size Control, Tissue Homeostasis, and Cancer. Cell. 2015;163(4):811–28
4. Zhang FF, Morioka N, Kitamura T, Hisaoka-Nakashima K, Nakata Y. Proinflammatory cytokines downregulate connexin 43-gap junctions via the ubiquitin-proteasome system in rat spinal astrocytes. Biochemical and biophysical research communications. 2015;464(4):1202–8.
PS02-064
Poster Viewing Session II
Lithium at low therapeutic concentrations decreases myosin light chain phosphorylation and thereby stabilizes human endothelial barrier
B. Bosche1,2, R.L. Macdonald1, M. Molcanyi3, S. Rej4, T.R. Doeppner2,5, M. Obermann2, D.J. Müller6, A. Das7, J. Hescheler3, F.V. Härtel7 and T. Noll7
1University of Toronto, Neurosurgery, Toronto, Canada
2University of Duisburg-Essen, Neurology, Essen, Germany
3University of Cologne, Neurophysiology, Cologne, Germany
4Sunny Brook Health Sciences Centre, University of Toronto, Division of Geriatric Psychiatry, Department of Psychiatry, Toronto, Canada
5University of Göttingen Medical School, Neurology, Göttingen, Germany
6Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Pharmacogenetics Research Clinic, Toronto, Canada
7Medical Faculty Carl Gustav Carus, Technical University of Dresden, Institute of Physiology, Dresden, Germany
Abstract
Lithium at serum concentrations up to 1.1 mmol/L were used in patients suffering from bipolar disorder for decades. Moreover, lithium has recently been shown to reduce the risk for ischemic stroke in these patients. The risk for stroke and thromboembolism depend not only on cerebral but also on general endothelial function and health; the entire endothelium as an organ is therefore pathophysiologically relevant. Regardless, our knowledge about the direct impact of lithium on endothelial function is poor.
We conducted an experimental study using lithium as pharmacologic pretreatment for murine, porcine and human vascular endothelium. We predominantly investigated endothelial vasorelaxation capacities in addition to human basal and dynamic (thrombin-/PAR-1 receptor agonist-impaired) barrier functioning including myosin light chain phosphorylation (MLC-P).
Low-dose therapeutic lithium concentrations (e.g., 0.4 mmol/L lithium) significantly augment the cholinergic endothelium-dependent vasorelaxation capacities of cerebral and thoracic arteries, independently of central and autonomic nerve system influences. Similar concentrations of lithium (0.2–0.4 mmol/L) significantly stabilized the dynamic thrombin-induced and PAR-1 receptor agonist-induced permeability of human endothelium, while even the basal permeability appeared to be stabilized. The lithium-attenuated dynamic permeability was associated with a reduced endothelial MLC-P known to be followed by a lessening of endothelial cell contraction and paracellular gap formation. The well-known lithium-associated inhibition of inositol monophosphatase/glycogen synthase kinase-3-β signaling-pathways involving intracellular calcium concentrations in neurons appears to similarly occur in endothelial cells, too, but with different down-stream effects such as MLC-P reduction.
This study discovered low-dose lithium as a drug directly stabilizing human endothelium and ubiquitously augmenting cholinergic endothelium-mediated vasorelaxation. Our findings have translational and potentially clinical impact on cerebrovascular and cardiovascular disease associated with inflammation, and may explain why a lithium treatment can reduce the risk for ischemic stroke. However, further investigations and particularly prospective clinical studies are warranted.
PS02-065
Poster Viewing Session II
Pathophysiology of high altitude traumatic brain edema. New roles of cererbrolysin and nanomedicine
D.F. Muresanu1,2, A. Sharma3 and H.S. Sharma3
1University of Medicine and Pharmacy, Clinical Neurosciences, Cluj-Napoca, Romania
2RoNeuro Institute for Neurological Research and Diagnostic, Neurology, Cluj-Napoca, Romania
3Uppsala University Hospital, Surgical Sciences, Anesthesiology & Intensive Care Medicine, Uppsala, Sweden
Abstract
Military personnel are vulnerable to traumatic brain injuries (TBI) during battlefield often occurring at high altitude (HA) above 4500 to 5000 meters. HA alone results in brain edema and mental dysfunctions. Whether additional TBI could further exacerbate HA induced pathophysiology of brain damage is still unknown. Animals were exposed to HA in a hypobaric chamber equivalent to 5000 m (53.8 kPa) for 1 week. TBI was induced in under Equithesin anesthesia by dropping a weight of 114.6 g from 20 cm height on right parietal skull (impact of 0.224 N). Control animals received identical TBI at sea level (200m). After 4, 8 and 12 h TBI, the animals blood-brain barrier (BBB) breakdown, edema formation and neuronal, glial and myelin injuries were examined. Rats subjected to TBI at HA exhibited 2- to 4-fold increase in BBB breakdown to Evans blue albumin (EBA) and radioiodine ([131]-I) tracers as compared to identical TBI at laboratory conditions. Reduction in cerebral blood flow (CBF) was 50 to 80% greater in HA as compared to normal controls after TBI. Brain edema formation was 3 to 4% higher in HA acclimated rats after TBI than the normal traumatized animals. Neuronal, glial and myelin damages were exacerbated in HA rats after TBI. The magnitude and intensity of HA induced TBI was progressive in nature. Cerebrolsyin (5 to 10 mg/kg, i.v.) when administered 30 min to 2 h after TBI thwarted brain pathologies at 4 h. However, TiO2-nanowired delivery of cerebrolysin (5 ml/kg, i.v.) 1 to 2 h after TBI is needed to reduces brain pathologies in HA animals up to 12 h. These observations are the first to point out that pathophysiology of TBI is exacerbated at HA and nanodelivery of cerebrolysin is required to induce neuroprotection at HA, not reported earlier.
PS02-066
Poster Viewing Session II
Enhanced interstitial fluid drainage in the hippocampus of spontaneously hypertensive rats
B. Bedussi1, D.M.P. Naessens1, J. de Vos1, R.H.G. Olde Engberink2, J. Titze3, M. Wilhelmus4, E. Richard5, M. ten Hove1, E. VanBavel1 and E.N.T.P. Bakker1
1Academic Medical Center (AMC), Biomedical Engineering and Physics, Amsterdam, Netherlands
2Academic Medical Center (AMC), Amsterdam, Netherlands
3Vanderbilt University, Division of Clinical Pharmacology, Nashville, United States
4Neuroscience Campus Amsterdam, VU Medical Center, Department of Anatomy and Neurosciences, Amsterdam, Netherlands
5Academic Medical Center (AMC), Department of Neurology, Amsterdam, Netherlands
Abstract
Hypertension is associated with cognitive decline and various forms of dementia, including Alzheimer's disease. Brain cells are embedded in interstitial fluid (ISF), which provides nutrients, oxygen, and removes waste. In addition, ISF enables both synaptic- and extra-synaptic transmission. We hypothesized that altered ISF drainage may be a consequence of hypertension. We therefore studied tracer distribution in ISF, using spontaneously hypertensive rats and normotensive Wistar Kyoto rats. At 8 months of age, infusion of a mix of high- and low-molecular weight fluorescent tracers (2 uL/30 min) into the hippocampus of anesthetized rats did not show a significantly altered tracer distribution between normotensive and hypertensive rats. However, when tracers were allowed to diffuse freely from the pipette into the hippocampus, a drastically enhanced spreading was observed in hypertensive rats as compared to normotensive rats (6 and-7 fold increase in distribution area, for high and low molecular weight tracers respectively; P< 0.01). Tracers moved further from the pipette than can be expected by diffusion alone, in an inhomogeneous pattern. Thus, tracer accumulated in the stratum lacunosum moleculare and hippocampal surfaces, particularly towards the third ventricle. These areas stained positive for astrocytes and aquaporin-4, and embedded many blood vessels. As water fluxes are driven by ionic transport, we also analyzed Na+ and K+ concentrations in whole brain samples. Hypertensive rats showed a disturbed ionic composition of the brain, with an increase in Na+/K+ ratio from 0.55 to 0.59 (P< 0.01) as compared to normotensive rats. This was accompanied by a tendency to develop tissue edema in hypertensive rats (P = 0.051). In conclusion, these data indicate enhanced bulk flow of ISF in the hippocampus of hypertensive rats. ISF drains towards the cerebrospinal fluid compartment, including the third and lateral ventricles, and paravascular spaces of arteries, following pathways set out by astrocytes.
PS02-067
Poster Viewing Session II
Delayed NK1 tachykinin receptor antagonist treatment reduces ICP following stroke in an Ovine model
A. Sorby-Adams1, A. Leonard1, E. Thornton1, D. Hunter1 and R. Turner1
1University of Adelaide, Adelaide Medical School and Adelaide Centre for Neuroscience Research, Adelaide, Australia
Abstract
Objectives: Brain swelling and elevated intracranial pressure (ICP) are life-threatening complications of stroke, associated with poor outcomes and significant mortality. Therapy is limited to osmotic agents or invasive decompressive surgery. As such, alternate treatments targeting the mechanisms of oedema and ICP elevation are urgently required. We have recently shown that acute (<24 h) NK1 tachykinin receptor antagonist treatment was as effective as decompressive craniectomy in lowering ICP following permanent Ovine middle cerebral artery (MCA) occlusion. As such, the aims of this study were to determine: 1) the temporal profile of elevated ICP following Ovine MCA occlusion with reperfusion; 2) when ICP rises above baseline; 3) the efficacy of NK1 tachykinin receptor antagonist treatment to reduce ICP.
Methods: Male and female Merino sheep (n = 48) were subject to 2h proximal MCA occlusion with reperfusion, achieved by direct application and removal of a temporary aneurysm clip, under Isoflurane anaesthesia. Following stroke, animals were removed from anaesthesia and allowed to recover. At 1, 2, 3, 4, 5, 6, or 7d (n = 6/time-point) following stroke animals were reanaesthetsied and ICP (Codman microsensors) monitored for 4hrs. NK1 antagonist (n = 6; R001; 1 mg/kg) treatment was administered (2 doses, 5 h apart) as a slow intravenous bolus at 5d following stroke onset.
Results: Following stroke, ICP rose over time and was significantly (p< 0.001) elevated above baseline at 5–6 d post-stroke, after which there was a trend towards return to baseline. NK1 tachykinin receptor antagonist treatment administered at 5d post-stroke was effective in significantly (p< 0.01) reducing ICP back to baseline levels.
Conclusions: NK1 tachykinin receptor antagonist treatment at the delayed time-point of 5 d post-stroke reduced ICP to baseline levels, suggesting that it may represent a novel approach to treat elevated ICP post-stroke.
PS02-068
Poster Viewing Session II
Quantification of mu-opioid receptor binding with 11C-Carfentanil PET: a comparison of ROI-methods using test-retest analysis
J. Johansson1, R. Ajalin1, J. Tuisku1, T. Karjalainen1, J. Joutsa2 and H. Scheinin3
1University of Turku, Turku PET Centre, Turku, Finland
2Massachusetts General Hospital, Harvard Medical School, Athinoula A. Martinos Center for Biomedical Imaging, Boston, United States
3Turku University Central Hospital, Turku, Finland
Abstract
Objective: The aim of this study was to evaluate the repeatability and reliability of manual and automated region-of-interest (ROI) methods in mu-opiod receptor (MOR) PET studies using test-retest analysis, as well as relative accuracy of the automated methods as compared to the current gold standard.
Methods: Automated ROI-extraction was conducted on the basis of T1w MRI-data using FreeSurfer. Manual ROI-delineation was used as a reference in the calculation of limits of agreement (LOA), while the test-retest characteristics, test-retest (TRT) variability (TRV%) and intraclass-correlation (ICC), were considered as the primary figures-of-merit. TRT parameters were calculated from six healthy volunteers scanned twice during the same day with 11C-Carfentanil and a conventional PET-scanner. Simplified reference tissue model (SRTM) with the occipital cortex (OCC) as a receptor-devoid reference region was used to estimate binding potentials (BP).
Results: Table 1 shows the results from chosen cortical and subcortical ROIs. TRT characteristics showed similar performance for automated and manual methods (Table 1). However, significant differences in BP estimates were observed (Table 1).
Region
Method
BP1
BP2
TRV%
ICC
LOA
NAcc
Manual
2.70 ± 0.35
2.74 ± 0.34
3.06 ± 1.46
0.97
FreeSurfer
2.57 ± 0.40
2.62 ± 0.38
4.35 ± 3.23
0.95
[−0.32 0.06]
Thalamus
Manual
2.26 ± 0.42
2.34 ± 0.40
4.04 ± 1.63
0.98
FreeSurfer
1.81 ± 0.32
1.89 ± 0.32
4.48 ± 1.52
0.97
[−0.70 −0.20]
Cing. ant.
Manual
1.22 ± 0.22
1.26 ± 0.21
4.60 ± 3.72
0.96
FreeSurfer
1.22 ± 0.25
1.26 ± 0.24
4.05 ± 3.99
0.97
[−0.11 0.10]
Amygdala
Manual
1.98 ± 0.35
2.06 ± 0.30
6.87 ± 3.48
0.89
FreeSurfer
1.71 ± 0.28
1.81 ± 0.23
7.33 ± 3.01
0.87
[−0.46 −0.07]
Conclusions: This study shows feasibility of automated ROI delineation in MOR PET studies, which holds a great potential of improved repeatability and cost efficiency through full automation of the analysis. However, as expected, the estimates of BP are not comparable between the methods.
PS02-069
Poster Viewing Session II
Measurement of cerebral blood flow with H215O PET/MRI
H. Okazawa1, T. Tsujikawa1, Y. Higashino2, H. Arishima2, T. Mori1, K.-I. Kikuta2 and Y. Kiyono1
1University of Fukui, Biomedical Imaging Research Center, Eiheiji-cho, Japan
2University of Fukui, Department of Neurosurgery, Faculty of Medical Sciences, Eiheiji-cho, Japan
Abstract
Introduction: Measurement of cerebral blood flow (CBF) using H215O-PET is useful and reliable approach to evaluate brain circulation and hemodynamic changes. Recently a new modality of PET/MRI system has been available for simultaneous acquisition of both images. The fusion of PET molecular function and high grade anatomical images in the same location is very beneficial in clinical use. However, it is very difficult to sample arterial blood from the patient during PET/MRI scans. In this study, a noninvasive method was used to estimate input function directly from brain H215O-PET scans for measurement of CBF.
Methods: Eleven healthy volunteers (9 males and 2 female, 43.9 ± 10.9 y) underwent H215O-PET/MRI studies using a whole body PET/MRI scanner (Signa PET/MR, GE Healthcare). A 3-min PET scan was started at the tracer injection time with list-mode acquisition. MRI scans for images of 3D-T1WI and arterial spin labeling (ASL) with 2.0 sec post-labeling delay (PLD) were acquired during the PET scan. PET images were reconstructed as dynamic data in frames of 12x5 sec, 6x10 sec, 3x20 sec using two types of resolution. The image derived input function (IDIF) method extracted the time-activity curves of the major cerebral artery from several image slices at the skull base in the dynamic PET data. CBF images were calculated using a single compartment model (CM) and a one tissue CM (1-TCM).
Results: The means of CBF from the single CM, 1-TCM, and ASL-MRI were 44.8 ± 4.3, 47.9 ± 5.9 and 57.9 ± 8.6 (mL/100 g/min), respectively. CBF from ASL-MRI was significantly greater compared with CBF from H215O-PET (P< 0.001). However, these CBF values were significantly correlated each other in the scatter plots (P< 0.05).
Conclusion: Noninvasive measurement of CBF using H215O-PET/MRI and IDIF provided reasonable quantitative values, which is useful for clinical application. The ASL-MRI perfusion image from the simultaneous acquisition tended to overestimate CBF values in healthy volunteers.
PS02-070
Poster Viewing Session II
Kinetic modelling of 18F-Fluoroethyl-tyrosine PET using an image derived arterial input function from the heart in small children
L. Marner1, M. Lundemann1, O.M. Henriksen1, C. Ladefoged1, C. Svarer2, A. Sehested3 and I. Law1
1Copenhagen University Hospital Rigshospitalet, Department of Clinical Physiology, Nuclear Medicine and PET, Copenhagen, Denmark
2Copenhagen University Hospital Rigshospitalet, Neurobiology Research Unit, Copenhagen, Denmark
3Copenhagen University Hospital Rigshospitalet, Department Paediatrics and Adolescent Medicine, Copenhagen, Denmark
Abstract
Objectives:18F-Fluoroethyl-tyrosine(FET) is an amino acid analog PET tracer used for brain tumor imaging. Although used clinically, the kinetics of the tracer is not thoroughly analyzed. We aim to investigate the feasibility of kinetic modeling using image derived arterial input function(IDIF) from the left ventricle.
Methods: The study is part of a larger study of FET PET in children with brain tumors. Three children below 2 years of age are included so far. Blood samples during the scan were drawn in two cases for plasma and whole blood counts. A 40 min dynamic PET recording after injection of 3 MBq/kg FET was performed on a hybrid 3T Siemens Biograph mMR with brain and heart in the field of view. Regions were placed in the left ventricle, healthy gray matter(GM), and tumor.
DCE perfusion imaging was obtained and the estimated blood volumes used in the compartmental analyses. 1 tissue compartment model (TCM), 2TCM, and Logan plot were compared to traditional tumor-to-GM-SUV-ratios. No correction for metabolites was deemed necessary*.
Results: Whole blood counts matched the IDIF. Plasma-over-whole-blood ratios of 1.1 and 1.2 were multiplied to the IDIF. For one subject the parameter estimations did not converge. The other subjects showed fairly similar AIC scores for 1TCM and 2TCM. The Logan plot resulted in similar distribution volumes(VT). GM VT were 0.5 and 0.7 while tumor VT were 1.1 (DVR: 2.2) and 1.1 (DVR: 1.6) as compared to maximal tumor-to-GM-SUV-ratios of 2.3 and 3.0.
Conclusions: Preliminary results demonstrate the feasibility of using left ventricle IDIF for kinetic analysis of FET imaging. VT showed smaller difference between GM and tumor in line with earlier reports**and is not preferable for clinical use. Further studies are needed to investigate alternative outcome measures.
References
* Pauleit et al(2003).EJNM30(4):519–24.
** Thiele et al.(2009).Phys.Med.Biol. 54:5525–39.
PS02-072
Poster Viewing Session II
Simultaneous resting state fMRI - FDG PET measurement in humans: Does the FDG-PET framing matter?
R. Rajkumar1,2,3, J. Mauler1, E. Rota Kops1, J. Arrubla1, L. Tellmann1, C. Lerche1, K.J. Langen1,4, H. Herzog1 and I. Neuner1,2,3
1Forschungszentrum Juelich GmbH, Institute of Neuroscience and Medicine 4 (INM4), Juelich, Germany
2RWTH Aachen University, Department of Psychiatry, Psychotherapy and Psychosomatics, Aachen, Germany
4RWTH Aachen University, Department of Nuclear Medicine, Aachen, Germany
Abstract
Various relationships between simultaneously measured resting state fMRI (rs-fMRI) and [18F]FDG PET parameters have been studied and reported. Every group uses schemes with different frame lengths for the analysis of simultaneously recorded FDG PET images. Within this pilot study (4 healthy volunteers, 26.75 ± 2.62 years) we compare six different timing schemes of the (averaged) FDG PET image (time frame length for 5, 10, 15, 20, 25, and 30 minutes, onset 27.5 minutes after FDG injection) with a 5 minute resting state PET image frame (rs-PET) acquired 50 minutes after FDG injection (172 ± 10.61 MBq [18F]FDG in a 3T MR-BrainPET system), reconstructed precisely during the rs-fMRI measurement (6 minutes/eyes closed). Intermodality comparison between PET and fMRI was performed by comparing the Z score standardised PET image frames (co-registered to MNI 152 template) with the Regional Homogeneity (ReHo) parameter (measure of local connectivity) of the rs-fMRI. Mean activity (in kBq/cc) in the posterior cingulate cortex (PCC) (10 mm spherical ROI) of the PET image frames and rs-PET image did not show any statistically significant difference.]Average voxelwise Pearson correlations (r) between the PET image frames and the rs-PET image are 0.89, 0.92, 0.93, 0.93, 0.95, and 0.96 (p = 0), respectively. Similarly, average voxelwise Pearson correlations between the PET image frames, the rs-PET and the fMRI-ReHo measure in dorsal default mode network (DMN) are 0.32, 0.33, 0.34, 0.33, 0.33, and 0.29 (p = 0), respectively.
Average voxelwise Pearson correlation (PET-frames Vs fMRI-ReHo) in the dorsal-DMN
The comparable average activity in the PCC, the high correlation with different PET image frames and a comparable correlation value with the fMRI-ReHo measure in the DMN, indicate that different analysis strategies in terms of time frame length appear to have no significant influence on the results. This must be replicated in a larger sample.
PS02-073
Poster Viewing Session II
Semiquantification of [11C]-(R)-PK11195 PET imaging in juxtacortical and periventricular regions in multiple sclerosis
A.M. Marques da Silva1, L.D.L. Narciso2, P.N. Schuck1, C.M. Dartora2, I.L. Alves3, C.S. Matushita4, J.C. da Costa4 and J. Becker4
1PUCRS, School of Physics, Porto Alegre, Brazil
2PUCRS, School of Engineering, Porto Alegre, Brazil
3Department of Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
4PUCRS, Brain Institute of Rio Grande do Sul, Porto Alegre, Brazil
Abstract
Objective: To investigate [11C]-(R)-PK11195 uptake in juxtacortical and periventricular regions in PET brain images of multiple sclerosis (MS) patients and control subjects.
Methods: Six controls and six MS subjects underwent MR and PET imaging, alongside a full clinical assessment, including the expanded disability status scale (EDSS). Juxtacortical and periventricular (JP) regions were determined in T1 MRI by the superposition of SPM segmented gray matter (GM) and white matter (WM) masks, followed by morphological operations. Normalized SUV using JP regions and healthy WM (SUVRWM) were calculated. MS lesions automatically extracted [1] from WM mask produced healthy WM regions in 3D FLAIR MRI. Differences between MS and control groups were evaluated with Student t test. Spearman's rank correlation coefficient with EDSS, age, time of disease and number of attacks were tested.
Results: SUVRWM for JP regions were (1.03 ± 0.01) for MS patients group and (1.07 ± 0.02) for control group (p< 0,01). Positive correlation was observed with age (0.54), and negative correlations with time of disease (0.94) and with number of attacks (0.72). No correlation was observed for EDSS (0.17).
Conclusions: MS data show significant differences in SUVRWM in JP regions compared to controls and and strong correlation with time and number of attacks. Patient symptoms and signs of inflammatory demyelinating in CNS (juxtacortical, periventricular, infratentorial, spinal cord), detected by lesions in MRI, are used in MS diagnosis [2]. Therefore, our findings support the potential use of PET semiquantification with [11C]-(R)-PK11195 as marker of MS disease activity, using SUV of JP regions, normalized by healthy WM.
References
[1] Schmidt P. et al. An automated tool for detection of FLAIR-hyperintense white-matter lesions in Multiple Sclerosis. Neuroimage. 2012;59(4):3774–3783.
[2] Polman CH, Reingold SC, Banwell B, et al. Diagnostic criteria for multiple sclerosis: 2010 Revisions to the McDonald criteria. Annals of Neurology. 2011;69(2):292–302.
PS02-074
Poster Viewing Session II
Experience and evaluation of Dual-Table Autoradiography (DTARG)123I-IMP SPECT: safe, time shortening, and effective modality to predict cerebral infarction in chronic ischemic patients
J. Suenaga1, M. Kishimoto1, R. Ueno1, R. Matsuzawa1, S. Seki1, T. Hayashi1, R. Miyazaki1, T. Nakamura1, M. Sato1 and H. Murata1
1Yokohama City University, Neurosurgery, Yokohama, Japan
Abstract
Background: IMP SPECT is widely used to evaluate perfusion status and vascular reserve function in brain ischemia. Recently dual table autoradiography(DTARG)Q-SPECT has been invented and it's worth because resting and Diamox loading test data are acquired in only single test. We report here our experience of DTARG and summarize clinical outcome according to the Power's staging classification.
Objective: From 89 patients 109 DTARG IMP SPECT data were examined for Internal Carotid Artery (ICA) or Middle Cerebral Artery (MCA) stenosis/occlusion in intracranial or neck region. According to the Japan Extra Cranial-Intra Cranial Trial (JET) study [Surg Cereb Stroke (Jpn) 30: 434-37, 2002], patients were divided into three groups. Stage 0 (resting cerebral blood flow (CBF) >80%, vascular reserve (VR) >10%): 38, stage I (CBF< 80%, VR>10%): 27, stage II (CBF< 80%, VR< 10%): 24.
Results: 1 transient nausea and 1 transient loss of consciousness were observed during the SPECT test (1.8%). There were ischemic event in follow up period. Stage 0 is 0% during 17.0 (1–51) months follow up, Stage I is 3.7% during 24.2 (1–88) months, and Stage II is 16.7% during 17.6 (1–51) months, P < 0.01.
Conclusion: This is not a randomized trial but a retrospective data, so there are large bias. But it was clear that stage 0 and I are low risk of future ischemia.
PS02-075
Poster Viewing Session II
Interrogating the GABAergic system with simultaneous [18F]Flumazenil-positron emission tomography and GABA-magnetic resonance spectroscopy in healthy volunteers
L. Fung1, R. Flores1, M. Gu2, C. Leuze2, T. Hjoernevik2,3, B. Shen2, J.-H. Park2, J.H. Jung4, B.C. Lee5, S.E. Kim5, J. McNab2, S. Srinivas2, D. Spielman2 and F. Chin2
1Stanford University, Psychiatry & Behavioral Sciences, Stanford, United States
2Stanford University, Radiology, Stanford, United States
3The Intervention Centre, Oslo University Hospital, Oslo, Norway
4BioImaging Korea, Seoul, Korea, Democratic People`s Republic of
5Seoul National University Bundang Hospital, Seoul, Korea, Democratic People`s Republic of
Abstract
Background: This pilot study aims at demonstrating the feasibility of simultaneous acquisition of GABAA receptor binding potentials and GABA levels by magnetic resonance spectroscopy (MRS) and positron emission tomography (PET) with [18F]Flumazenil ([18F]FMZ) as radiotracer in healthy volunteers.
Methods: Participants were scanned on GE SIGNA PET/MR (Waukesha, WI). PET data were acquired in list mode (0–60min p.i), dynamically reconstructed and corrected for photon attenuation using both scanner-specific 8-channel headcoil correction and a MR-measured head atlas-based attenuation correction maps. During PET data acquisition, a series of MR structural sequences were acquired, including (a) T1-weighted MP-RAGE sequence, and (b) T2-weighted fast-spin-echo sequence. For the MRS measurement of GABA, MEGA-SPECIAL was performed on the left dorsolateral prefrontal cortex (DLPFC) and bilateral thalami. The dynamic PET and structural MR data were normalized to MNI (Montreal Neurological Institute) space (PMOD 3.7, Switzerland). Time-activity curves were extracted using pre-defined volumes-of-interest. A reference tissue model (Ichise model; MRTM0) was used to calculate binding potentials (BPND) with pons as the reference region. The MEGA-SPECIAL edited spectrum was obtained by subtracting the editing OFF spectrum from the editing ON spectrum. GABA level was estimated from the integrated 3ppm peak area in the edited spectrum divided by the Cre peak area.
Results and conclusions: We have successfully acquired [18F]FMZ-PET, structural MRI, and MRS data with a simultaneous PET/MR imaging system in six healthy male volunteers (mean age 34 years; range 30 to 42 years). Highest uptake was observed in the neocortical regions (BPND = 5.2 ± 1.5) and limbic system (BPND = 4.2 ± 0.9), intermediate in the cerebellum (BPND = 3.2 ± 1.1), thalami (BPND = 2.0 ± 0.3), and basal ganglia (BPND = 2.2 ± 0.4), and low uptake in the brainstem (BPND = 0.4 ± 0.1). The estimated GABA/Cre ratios in the left DLPFC and thalami are 4.7 ± 1.8% and 8.0 ± 5.3%, respectively. We demonstrated that simultaneous acquisition of GABAA receptor BPND and GABA levels is feasible in healthy volunteers.
PS02-076
Poster Viewing Session II
Clustering serotonergic key players of the human cortex using positron emission tomography and FreeSurfer
G.M. James1, G. Gryglewski1, C. Vraka2, R. Seiger1, V. Pichler2, L. Silberbauer1, L. Nics2, B. Spurny1, M. Spies1, M. Mitterhauser2,3, A. Hahn1, W. Wadsak2,4, M. Hacker2, S. Kasper1 and R. Lanzenberger1
1Medical University of Vienna, Psychiatry and Psychotherapy, Vienna, Austria
2Medical University of Vienna, Biomedical Imaging and Image-guided Therapy, Division of Nuclear Medicine, Vienna, Austria
3Ludwig Boltzmann Institute for Applied Diagnostics, Vienna, Austria
4Center for Biomarker Research in Medicine, Graz, Austria
Abstract
Objectives: The serotonergic system of the human brain is involved in a variety of neural functions, such as mood regulation, appetite, sleep cycles, but also in several psychiatric disorders [1]. We aimed to segment [2] the cerebral cortex according to similarities in the distribution of serotonergic key players and beyond anatomical boundaries. The main inhibitory serotonin receptor (5-HT1A), the transporter (SERT) and the serotonin-degrading enzyme monoamine oxidase A (MAO-A) were assessed.
Methods: PET data of 54 healthy subjects was used (n = 18 matched subjects for each protein) for 5-HT1A (mean age 27.50 ± 6.53), SERT (28.22 ± 6.65) and MAO-A binding (28.72 ± 5.98). After movement correction (SPM12), each map was quantified in individual space (BPND or VT, PMOD). Coregistration to structural MR, partial volume correction and surface mapping was done using Freesurfer. Binding values for each protein were averaged across subjects and z-standardized to correct for different quantification units and finally partitioned by performing K-means clustering (k = 5–25).
Results: Even with varying amounts of clusters, similar structures evolved from the parcellation. These consist particularly of the prefrontal cortex, inferior temporal lobe, cingulate cortex and somatosensory areas.
Conclusion: We propose a parcellation of the serotonin neurotransmitter system according to the binding of three major components across the cerebral cortex. These clusters may serve as an alternative basis for the analysis and interpretation of data involving serotonin neurotransmission where conventional parcellations based on anatomy, cytoarchitecture or function may not be able to capture the relevant molecular information.
References
[1] Spies, M., Knudsen, G.M., Lanzenberger, R. & Kasper, S. 2015 The serotonin transporter in psychiatric disorders: insights from PET imaging. Lancet Psychiatry 2, 743–755.
[2] Yang, Y., Fan, L., et al. 2016 Identifying functional subdivisions in the human brain using meta-analytic activation modeling-based parcellation. Neuroimage 124, 300–309.
PS02-077
Poster Viewing Session II
Evaluation of methods for a simultaneous, dual-radiotracer acquisition in translational SPECT neuroimaging
S. Tsartsalis1,2,3, B.B. Tournier1, S. Habiby1, C. Barca1, A. Dimiziani1,3, D. Pandolfo1,3, N. Ginovart1,3 and P. Millet1,3
1Geneva University Hospitals, Department of Mental Health and Psychiatry, Vulnerability Biomarkers Unit, Geneva, Switzerland
2Geneva University Hospitals, Department of Mental Health and Psychiatry, Division of Addictology, Geneva, Switzerland
3University of Geneva, Department of Psychiatry, Geneva, Switzerland
Abstract
Objectives: Modern molecular neuroimaging provides tools for the study of brain chemistry with radiotracers targeting a wide spectrum of neuroreceptors. Studying multiple targets simultaneously is of utmost importance. Small-animal SPECT offers this potential if using isotopes with different emission spectra, such as I123 and I125. However, I123 emits at a secondary energy window that is the same with that of I125. We evaluate three different methods of correction of this cross-talk for the distinction of radioactive signals in a dual-radiotracer, small-animal SPECT scan.
Methods: A dual-radiotracer, dynamic scan (120 × 1-minute frames) was performed in three rats with the injection of [I125]R91150 (5-HT2A receptors) at T = 0, followed by the [I123]IBZM (striatal D2 receptors) à T = 20 minutes. The following methods were employed for the correction of cross-talk with the I125 signal: 1) an estimation of the secondary I123 signal from the primary one given their linear relationship, 2) the use of Factor Analysis (FA) to distinguish the different energy-spectral profiles of signals emanating from the two radiotracers and 3) a method based on the compartmental modeling of the two radiotracers' kinetics. Binding potential (BPND) was estimated region-wise and results were compared with those from a control-group of single-tracer, unbiased [I125]R91150 SPECT scans by means of linear regression analysis.
Results: All three methods provide similar results of the correction of I125 signal from I123-derived cross-talk. BPND values are equally close to those obtained from the control group scans: r = 0.92, p< 0.001 for method (1), r = 0.95, p< 0.001 for method (2) and r = 0.95, p< 0.001 for method (3).
Conclusions: These results suggest that simultaneous, dual-radiotracer small-animal SPECT imaging is technically feasible with virtually any couple of radiotracers labeled with I123 and I125, thus expanding the findings of this study to a very wide spectrum of applications in translational neuroimaging.
PS02-078
Poster Viewing Session II
Human brain energy map computed on the basis of cellular staining from BigBrain
Y. Yu1 and F. Hyder2
1Fudan University, Shanghai, China
2Yale School of Medicine, New Haven, United States
Abstract
Recent human brain PET maps of oxygen and glucose utilization indicated that most of resting awake human brain regions are supported by similar high oxidative glucose (CMRglc(ox)) in supporting ubiquitously high resting activity. This challenges the prevailing view of sparsed and low (<0.1 Hz) neuronal activity rate. To provide a clear quantitative energy interperation of PET maps of glucose consumption, we aimed here to construct computationally the first 3D brain digital CMRglc(ox) map to mimic PET-measured CMRglc(ox) data of the living human brain by using energy budget calculation with a set of ultrahigh-resolution human brain cellular stain data. Correspondingly, 3D brain neuronal activity map was generated to examine the neuronal activity distribution across brain regions during resting state. The digital energy map revealed that non-signaling-dependent energy cost in different brain regions are more equally distributed (less than 5% variance), while there is more diversity (over 20% variance) in signaling-dependent metabolic costs among brain regions, suggesting that there are specific brain network circuitries active for the particular brain states (e.g., sleep or wake-up). The model verified the <10% CMRglc(ox) variation across cortical and subcortical regions, and predicted an relatively high neuronal activity rate of 1.15 Hz on average for most cortical regions.
The constructed energy and activity maps provide, on a voxel-by-voxel basis, a quantitative interpretation of energy allocation to both non-signaling- and signaling-dependent processes, thus enabling a framework to test cellular-based hypotheses of different behavioral and/or diseases states, and which can be confirmed by in vivo PET and 13C-MRS studies.
PS02-079
Poster Viewing Session II
PET quantification of binding of a novel tau radioligand, 18F-AM-PBB3, in consideration of time-dependent changes in its plasma free fraction
S. Kitamura1, Y. Kimura1,2, M. Ichise1, C. Seki1, H. Shimada1, H. Shinotoh1,3, M. Kubota1, K. Takahata1, Y. Takado1, S. Moriguchi1, T. Ishii1, M.-R. Zhang4, T. Suhara1 and M. Higuchi1
1National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, Department of Functional Brain Imaging Research, Chiba, Japan
2Center for Development of Advanced Medicine for Dementia, National Center for Geriatrics and Gerontology, Department of Clinical and Experimental Neuroimaging, Obu, Japan
3Neurology Chiba Clinic, Chiba, Japan
4National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, Department of Radiopharmaceutics Development, Chiba, Japan
Abstract
Objectives: A novel tau PET ligand, 18F-AM-PBB3, has been developed by structural modifications of 11C-PBB3. Time-activity curves (TACs) in the brain obtained by human PET indicated a good radioligand uptake after injection consistent with reversible binding kinetics. Plasma parent TAC showed an initial rapid rise followed by a decline, which then plateaued with no further decreases. We hypothesized that the plasma parent free fraction may not be constant but rather decrease with time, and therefore analyzed kinetics of 18F-AM-PBB3 with plasma input functions corrected for sequentially measured parent free fractions.
Methods: One Alzheimer's disease (AD) and one healthy control (HC) subject underwent a dynamic PET scan, arterial blood sampling, and free fraction measurements after injection of 18F-AM-PBB3. We estimated two plasma input functions with and without free fraction corrections. One- and two-tissue compartment analyses (1TCM, 2TCM) were performed for both input functions to estimate binding potential (BPND) using cerebellar gray matter as reference. A reference tissue model (MRTMO) was also applied to estimate BPND without using blood data. We compared curve fitting and BPND values between these methods to evaluate the validity of the input correction for the plasma free fraction in compartment modeling.
Results: Plasma parent free fractions decreased over time (AD: 2.3%, HC:3.0% at 3 min and AD: 0.37, HC: 0.41% at 180 min). 2TCM produced a better fit to tissue TACs than did 1TCM with corrected input functions. Neither 1TCM nor 2TCM with uncorrected inputs described tissue TACs well. BPND values estimated by 2TCM with corrected inputs and MRTMO were in an excellent agreement.
Conclusions: Plasma inputs corrected for free fractions, which decreased over time, allowed quantification of 18F-AM-PBB3 binding using 2TCM, and a good correlation was found between estimates by this method and more practical reference tissue model requiring no plasma data.
PS02-080
Poster Viewing Session II
Inferring DVR values from short dynamic PET scans of 11C-DTBZ in rat, mouse and human striatum
A. Avendaño-Estrada1 and M.Á. Ávila-Rodríguez1
1Universidad Nacional Autónoma de México, Unidad Radiofarmacia-Ciclotrón, Facultad de Medicina, México, Mexico
Abstract
Quantitative graphical analysis PET images requires the acquisition of time consuming dynamic data from the moment of dose injection (t0 = 0) until the kinetics reaches equilibrium at a time T. There are some cases were it is difficult to acquire dynamic data from the moment of injection, compromising the accuracy of quantification with limited data. The purpose of this research aims to explore the feasibility to infer striatal distribution volume ratio (DVR) values from short dynamic scans acquired from a time t after injection (non-zero initial condition), using Logan's Reference Tissue Model (LRTM) and logistic regression.
Full dynamic studies (T = 65 min) from the moment of dose injection (t0 = 0) were acquired with 11C-(+)-α-dihidrotetrabenazine (11C-DTBZ) in rats, mouse and humans. Healthy controls and Parkinson's disease (PD) subjects were included for rats and humans. LRTM was applied under two conditions: a) using all the acquired dynamic data at a zero initial condition (i.e., integrating from t = 0 to T) to obtain the DVR value, and b) using limited dynamic data at a non-zero initial condition (integrating from t>0 to T, with t = 10, 20, 30 and 55 min) to obtain DVR* values as a function of t. A logistic regression was applied to the DVR* data aiming to obtain a Φ function so that we can infer the true DVR value using the equation DVR = ΦDRV*, were Φ = 0.5*(1+exp(-αt)). Note that α is obtained from the logistic regression, and is a specie and disease-dependent variable. We found that reduction of dynamic data does not significantly affect striatal DVR values. The maximum difference of DVR* values from the true DVR value was of 5% showing that it is possible to obtain a logistic regression function to infer reliably DVR values from short dynamic acquisitions. This method was successfully applied in different species, in healthy and PD conditions. Research supported by UNAM-DGAPA-PAPIIT IT201115.
PS02-081
Poster Viewing Session II
Evaluating the gray and white matter energy budgets of human brain function
Y. Yu1 and F. Hyder2
1Fudan University, Shanghai, China
2Yale School of Medicine, New Haven, United States
Abstract
Brain function's insatiable appetite for energy is supplied by glucose oxidation (CMRglc(ox)). But how much energy is consumed by signaling and nonsignaling processes in gray/white matter is highly debated. We examined this issue by combining metabolic measurements of gray/white matter and a theoretical calculation of bottom-up energy budget using biophysical properties of neuronal and glial cells in conjunction with species-exclusive electrophysiological and morphological data. We calculated a CMRglc(ox)-derived budget and confirmed it with experimental results measured by PET, autoradiography, 13C-MRS, and electrophysiology techniques. Several conserved principles were observed regarding the energy costs for brain's signaling and non-signaling components for both human and rat. Awake resting cortical signaling processes and mass-dependent nonsignaling processes demand ∼70% and ∼30% of CMRglc(ox), respectively. Inhibitory neurons and glia need 15–20% of total energy, with the rest demanded by excitatory neurons. Nonsignaling demands dominate in white matter, in near opposite contrast to gray matter demands. Comparison between 13C-MRS data and calculations suggest ∼1 Hz glutamatergic signaling rate in the awake resting human cerebral cortex, which is much higher than previous estimates. Top-down validation of bottom-up budgets could allow computation of anatomy-based CMRglc(ox) maps and accurate interpretation of brain imaging signal components.
PS02-082
Poster Viewing Session II
StO2-MRI sensitively images the ischemic brain: a comparison to MRI perfusion/diffusion mismatch and [18F]-FMISO-PET
S. Valable1, J. Toutain1, D. Divoux1, L. Chazalviel1, A. Corroyer-Dulmont1, A. Chakhoyan1, M. Ibazizene2, L. Barré2, E. Mackenzie1, M. Bernaudin1, E. Barbier3 and O. Touzani1
1Normandie-Univ, UNICAEN, CEA, CNRS, ISTCT/CERVOxy group, Caen, France
2Normandie-Univ, UNICAEN, CEA, CNRS, ISTCT/LDM-TEP group, Caen, France
3Inserm, U1216, Université Grenoble Alpes, Grenoble Institut des Neurosciences, Grenoble, France
Abstract
Introduction: Techniques capable of mapping hypoxia, following stroke, are sought after to obtain insight into the pathophysiological status of brain tissue and potentially assist in the selection of patients for individualized therapeutic interventions. MRI-based imaging of brain oxygen saturation (StO2-MRI) was described without a formal validation. Based on the use of multiparametric MRI and [18F]-FMISO PET, we analyzed the ability of StO2-MRI to depict the spatial heterogeneity of brain tissue in the acute phase of stroke.
Material and methods: In the same rat, diffusion-weighted-, perfusion-weighted- and StO2-MRI, as well as [18F]-FMISO-PET examinations were performed at 3h following middle cerebral artery occlusion (MCAo). T2-weighted MRI was repeated at 24h after MCAo.
Results: The volume of tissue with decreased StO2-MRI and that with increased uptake of [18F]-FMISO were equivalent and correlated (r = 0.706; p = 0.015). StO2 imaging detected a heterogeneously reduced tissue oximetry in the affected hemisphere. The values of StO2 in the penumbra were significantly greater than those quantified in the ischemic core, and less than those of the contralateral hemisphere (52.3±2.0%; 43.3 ± 1.9% and 67.9 ± 1.4%, respectively). ROC analyses revealed a threshold value of StO2-MRI of ≈60% as the cut-off for the identification of the penumbra.
Conclusion: The StO2-MRI approach is highly sensitive for the detection of different pathophysiological compartments following stroke and for the prediction of the final lesion volume. Given the simplicity of this approach, the detection of abnormally oxygenated tissue in acute clinical settings is both feasible and highly desirable, for a more rigorous selection of treatable patients.
PS02-083
Poster Viewing Session II
Effects of long-term caffeine consumption on the adenosine A1 receptor in the rat brain: An in vivo PET study with [18F]CPFPX
D. Nabbi-Schroeter1, D. Elmenhorst1,2, A. Oskamp1, S. Laskowski1, A. Bauer1,3 and T. Kroll1
1Forschungszentrum Jülich GmbH, Institute of Neuroscience and Medicine (INM-2), Jülich, Germany
2Rheinische Friedrich-Wilhelms-University Bonn, Psychiatry and Psychotherapy, Medical Psychology, Bonn, Germany
3Heinrich-Heine-University Düsseldorf, Neurological Department, Medical Faculty, Düsseldorf, Germany
Abstract
Caffeine is the most popular psychostimulant worldwide and plays as a nonselective antagonist of adenosine receptors an important role in physiological processes such as sleep and arousal. Furthermore, a protective role of chronic and moderate caffeine consumption against neurodegenerative diseases has been discussed. Thus, aim of the present study was an in vivo investigation of effects of long-term caffeine consumption and its subsequent withdrawal on the adenosine A1 receptor (A1AR) in the rat brain.
Methods: Sixteen adult, male rats underwent five positron emission tomography (PET) scans with the selective A1AR radioligand [18F]CPFPX in order to determine A1AR availability. After the 1st baseline (BL) PET scan, animals were assigned to two groups: caffeine-treatment and control group. The caffeine-treated animals received caffeinated tap water (30 mg/kg bodyweight/day, corresponding to 4–5 cups of coffee per day in humans) for 12 weeks. Subsequently, caffeine was withdrawn and repeated PET measurements were performed on day 1, 2, 4, and 7 of caffeine withdrawal. The control animals were measured according to the same time schedule.
Results: At day 1, after 4.4 hours of caffeine withdrawal, a significant decrease (−34.5%, p< 0.001) of whole brain A1AR availability was observed. Unlike all other investigated brain regions in caffeine treated rats, hypothalamus and nucleus accumbens showed no significant intraindividual differences between BL and 1st withdrawal PET scan. After approximately 27 hours of caffeine withdrawal the region- and group-specific effects disappeared and A1AR availability settled around BL.
Conclusions: The present study provides evidence that chronic caffeine consumption does not lead to persistent changes in functional availability of cerebral A1ARs which have previously been associated with neuroprotective effects of caffeine. The acute and region-specific decrease in cerebral A1AR availability directly after caffeine withdrawal is most likely caused by residual amounts of caffeine metabolites disguising an unchanged A1AR expression at this early time-point.
PS02-084
Poster Viewing Session II
Differences in TSPO and cannabinoid receptor CB2 binding at an early stage in poststroke neuroinflammation in living rats
Y. Ouchi1, D. Fukumoto2, T. Kakiuchi2, S. Nishiyama2, S. Yamamoto2, T. Hosoya1 and H. Tsukada2
1Hamamatsu University School of Medicine, Hamamatsu, Japan
2Hamamatsu Photoincs KK, Hamamatsu, Japan
Abstract
Objectives: It is considered that upregulations of translocator proteins (TSPO) and endocannabinoid receptors type 2 (CB2) reflect different aspects of microglia-related neuroinflammatory responses in the brain. While the TSPO expression elevates a bit later during neuroinflammation that is known as the proinflammatory process, CB2 activation is likely to engage in the neuroprotective responses occurring dominantly at an early stage of brain disorders. These findings, however, were deduced from the studies with different animal samples under different experimental settings. Here, we examined the different responses between TSPO binding and CB2 availability in the experimental setting for stroke in the same animal using PET.
Methods: We used a total of 8 Sprague-Dawley rats with the photothrombotic stroke surgery. The binding levels of a TSPO tracer [11C](R)PK11195 and a CB2 tracer [11C]NE40 in the same animal were measured at 24 hours after the surgery using PET in combination with immunohistochemistry for CB2 and several other markers. The in vivo morphological inspection was also performed with small animal-purpose X-ray computer tomography. This study was approved by the ethical committee of our university.
Results: [11C]NE40 BPND levels were found significantly higher in the peri-infarct region on the lesion side than those on the non-lesion side, while no difference was observed in levels of [11C](R)PK11195 BPND between hemispheres. The R1 data were all reduced on the lesion side irrespective of tracers. This increase in [11C]NE40 BPND was concurrent with an elevation of CB2 expression chiefly within the microglia in the peri-infarct area as shown by immunohistochemical examinations with Iba-1, CD11b/c+ and NG2+ staining.
Conclusion: The current findings suggest in vivo evidence of different responses of microglia occurring at an acute state of brain insult. An application of the CB2 tracer [11C]NE40 can elucidate the neuroprotective aspect of microglia that may be implicated during an acute neuroinflammatory event.
PS02-085
Poster Viewing Session II
In vivo changes in neurotransmitter and metabolite levels following selective activation of the nigrostriatal dopaminergic pathway
S. Baerentzen1, A. Casado-Sainz1, E.N. L'Estrada1,2, F.G. Edgar2, C. Kjaerby3, H. Lee4, H. Benveniste4, M. Herth1,2 and M. Palner1
1Copenhagen University Hospital, Neurobiology Research Unit, Copenhagen, Denmark
2University of Copenhagen, Faculty of Health and Medicine, Department of Drug Design and Pharmacology, Copenhagen, Denmark
3University of Copenhagen, Faculty of Health and Medicine, Center for Basic and Translational Neuroscience, Copenhagen, Denmark
4Yale University, Department of Anesthesiology, New Haven, United States
Abstract
Objectives: Insertion of Gq coupled receptors, DREADDs (Designer Receptors Exclusively Activated by Designer Drugs), in tyrosine hydroxylase (TH) Cre-positive rats, enable specific activation of TH-positive neurons via administration of the compound Clozapine N-oxide (CNO). Selective stimulation of the nigrostriatal dopaminergic pathway via Gq DREADDs is expected to cause burst activation of the nigrostriatal dopaminergic neurons leading to increased dopamine release and behavioural responses.
Methods: (Female) TH Cre-positive Long Evans rats (LE Tg(TH:Cre 3.1 Deis) were injected with a primarily retrogradely transfecting Gq coupled DREADD (AAV6-hSYN-DIO-hM3Dq-mCherry) bilaterally in the dorsal striatum. Following transfection, the neurometabolic (1H Nuclear Mangetic Resonance Spectroscopy) and dopaminergic ([18F]Fallypride Positron Emission Tomography) levels as well as a locomotor activity were recorded in all animals at baseline and after CNO administration.
Results: Activation of the nigrostriatal pathway by Gq DREADD and CNO administration increase the total distance moved between 30–60 minutes post administration from 2274 ± 1792 cm to 8143 ± 2621 cm, furthermore it decreased the dopamine D2 receptor availability in the dorsal striatum by 25 ± 6% while dorsal striatal glutamate and glutamine levels were unaffected.
Conclusions: Stimulation of the Gq DREADD receptor in the nigrostriatal dopaminergic pathway elicits behavioral hyperactivity as well in vivo neurochemical changes that indicating release of dopamine.
PS02-086
Poster Viewing Session II
The effect of hypothyroidism on the serotonin 1A receptor binding in the rat brain
J.Y. Choi1, J.H. Lee1, M. Lee2, J.A. Park3, K.C. Lee3, J.H. Kang3 and Y.H. Ryu1
1Yonsei University College of Medicine/Gangnam Severance Hospital, Seoul, Korea, Republic of
2Inha University School of Medicine/Inha University College of Medicine/Inha University Hospital, Incheon, Korea, Republic of
3Korea Institute of Radiological & Medical Sciences, Seoul, Korea, Republic of
Abstract
Purpose: Although the previous studies have demonstrated that malfunction of HPT axis is associated with alterations in the neurotransmission, there have been few studies on the influence of the HPT axis to the serotonergic system in the living system. Therefore, the aim of this study was to investigate the effect of thyroidectomy on the brain serotonin 1A receptors in vivo.
Methods: Surgically removal of thyroid (TXT) or pituitary gland rats (HXT), and sham operated Sprague-Dawley rats were utilized for [18F]Mefway PET scans for quantification of serotonin 1A receptors in the brain. PET data were reconstructed in user-defined time frames (10 sec × 6 frames, 30 sec × 8 frames, 300 sex × 5 frames, 1800 sec × 5 frames) by a 2-dimentional order-subset expectation maximization (OSEM) algorithm (4 iterations and 16 subsets). Volumes of interests (VOIs) are the hippocampus, septum, and cerebellum. Here, we used a fluconazole as an anti-defluorination drug in vivo. Non-displaceable binding potential (BPND) were estimated by MRTM2.
Results: VOI and voxel voxel based analysis also showed the enhanced brain uptakes for TXT or HXT group. Time activity curves showed that the brain uptake values for TXT or HXT were about 21–52% higher than those for sham group. In TXT group, binding potential values in the septum and the hippocampus were 20–26% higher than those in sham group. In HXT group, the septal binding values were similar whereas hippocampal binding values were 23% high compared with sham.
Conclusion: We suggested that the dysfunction of HPT axis causes the enhanced serotonin 1A receptor binding in the brain.
PS02-087
Poster Viewing Session II
In vitro and in vivo evaluations of an inhibitory effect of dopamine on [18F]FE-PE2I binding to dopamine transporters in rat brains
C. Seki1, M. Tokunaga1, J. Maeda1, F. Kodaka2, Y. Kimura1,3, H. Takuwa1, Y. Ikoma4, H. Ito1,5, T. Suhara1 and M. Higuchi1
1National Institutes for Quantum and Radiological Sciences and Technology, Department of Functional Brain Imaging Research, Chiba, Japan
2The Jikei University School of Medicine, Department of Psychiatry, Tokyo, Japan
3National Center for Geriatrics and Gerontology, Department of Clinical and Experimental Neuroimaging, Obu, Japan
4National Institutes for Quantum and Radiological Sciences and Technology, Department of Molecular Imaging and Theranostic, Chiba, Japan
5Fukushima Medical University, Department of Radiology and Nuclear Medicine, Fukushima, Japan
Abstract
Introduction: [18F]FE-PE2I is a selective PET radioligand for dopamine transporters (DATs). It is of great significance to investigate influences of endogenous dopamines on [18F]FE-PE2I binding to DAT. In this study, we conducted in vitro autoradiography and in vivo PET assays to examine whether dopamine inhibits specific binding of [18F]PE2I in rat brains.
Methods: Autoradiography was performed using fresh-frozen Sprague-Dawlay (SD) rat brain sections containing the striatum and cerebellum (n = 4 at each DA concentration). These samples were reacted with 0.5 nM [18F]PE2I in 50 mM Tris-HCl containing 0–10 mM of dopamine. Binding potential (BP) was calculated as a striatum-to-cerebellum ratio of average radioactivity minus 1.In vivo PET was conducted for SD rats (n = 6) under awake conditions without anesthesia. Increase of endogenous dopamine at synapses was induced by intravenous administration of haloperidol (0.1 mg/kg) at 20 min before PET. Baseline scans were also performed following saline instead of haloperidol injection. Ninety-minute PET scan was performed using microPET Focus 220 PET scanner. Non-displaceable binding potential (BPND) was quantified with simplified reference tissue model using the cerebellum as a reference. BPND values between conditions were statistically examined by paired t-test,
Results: Autoradiography showed no overt inhibition of [18F]FE-PE2I binding by dopamine, as IC50 values based on a 2-site binding model were 8.26 µM (high) and 1.91 mM (low), which were much higher than physiological dopamine concentrations (10–20 nM). BPND values determined by PET were 1.8 ± 0.18 and 1.89 ± 0.15 (mean ± s.d.) at baseline and after haloperidol administration, respectively, which were not statistically different.
Conclusion: The present results imply that alterations of synaptic dopamine concentrations do not influence [18F]FE-PE2I binding to DAT.
PS02-088
Poster Viewing Session II
[18F]FDG PET imaging reveals that metyrapone attenuates hypermetabolism and brain damage induced by seizures triggered by intrahippocampal 4-aminopyridine in rats
L. García-García1,2, R. Fernández de la Rosa2, M. Delgado2, F. Gomez1,2 and M.A. Pozo2,3,4
1Universidad Complutense de Madrid, Facultad de Farmacia, Dpto. Farmacología, Madrid, Spain
2Universidad Complutense de Madrid, Instituto Pluridisciplinar, Madrid, Spain
3Universidad Complutense de Madrid, Facultad Medicina, Dpto. Fisiologia, Madrid, Spain
4Instituto Tecnológico PET, Madrid, Spain
Abstract
Objective and aim: Glucocorticoids are known to exacerbate the neuronal damage induced by many neurological insults. Herein, we sought to explore the eventual protective effects of inhibiting the corticosterone response to the seizure induced by the intrahippocampal administration of the K+ channel blocker 4-aminopyridine (4-AP).
Material and methods: Reduction of corticosterone synthesis in the male Sprague-Dawley rats was achieved by a single dose of the 11β-hydroxylase inhibitor metyrapone (150 mg/kg, ip) 3 h before 4-AP injection (7 µg/5 µl). Immediately after, the PET tracer [18F]FDG (13 MBq/rat, i.v.) was injected to evaluate in vivo brain metabolism (Albira PET, Oncovision, Spain). Metabolic activity was assessed by the standardized uptake value (SUV) as well as by the statistical parametric mapping (SPM) analyses. Three days later, the brains were collected and processed to analyze various markers of brain damage such as hippocampal integrity (Nissl staining) and neurodegeneration (Fluoro-Jade C).
Results: The tonic-clonic seizures triggered by 4-AP were associated to a significant acute increase in metabolism in the ipsilateral hippocampus (SUVCONTROL = 1.72 ± 0.17 vs SUV4-AP = 3.38 ± 0.22) as well as in the markers of neuronal damage measured 3 days later. Conversely, metyrapone acutely reduced the focal increased [18F]FDG uptake induced by the convulsant agent (SUVMET = 2.53 ± 0.14 vs SUV4-AP = 3.38 ± 0.22) and also showed neuroprotective effects as reflected by the histological examinations.
Conclusion: Our study adds the 4-AP-induced seizure to the many neurological insults that are exacerbated by glucocorticoids and points towards pharmacological modulation of glucocorticoid milieu and stress management as therapeutic strategies to treat and/or prevent the neurological consequences of seizures and epilepsy. Nevertheless, further studies are needed to unveil the neuroprotective effects of metyrapone.
PS02-089
Poster Viewing Session II
Hybrid PET/MRI imaging in healthy unsedated newborn infants with quantitative rCBF measurements using 15O-water PET
J.B. Andersen1, U. Lindberg1, O.V. Olesen1, D. Benoit1, C.N. Ladefoged1, H.B.W. Larsson1, L. Højgaard1, G. Greisen2 and I. Law1
1Rigshospitalet, University of Copenhagen, Department of Clinical Physiology, Nuclear Medicine and PET, København, Denmark
2Rigshospitalet, University of Copenhagen, Department of Neonatology, København, Denmark
Abstract
Objectives: To investigate the feasibility of quantitative regional cerebral blood flow (rCBF) in healthy newborn subjects using PET with low-activity 15O-water and an image derived input function (IDIF) previously developed in a piglet model on a hybrid PET/MRI scanner.1
We wished to establish a proof-of-concept of the applied PET method for medical research use in newborn infants.
Methods: Four healthy full-term newborn subjects with mean age 2.5 days (range 2–3 days) and mean weight 3.4 kg (range 3.3–3.7 kg) were scanned in a PET/MRI during natural sleep injecting median activity 14 MBq 15O-water. This corresponds to an effective dose of 0.33 mSv, which is the approximate background radiation dose per month for the general public in Denmark. The study was approved by the Regional Scientific Ethical Committee of the Capital Region of Denmark, and oral and written informed consent was obtained from the children's' parents according to the Helsinki II declaration.
Regional CBF was quantified using a 1-tissue-compartment model employing an IDIF from a dynamic sequence of images of the left ventricle. Volumes of interest (VOIs) were drawn individually including whole brain, periventricular unmyelinated white matter, thalamus, striatum and cortex.
Results: PET rCBF distribution showed relatively high rCBF in the striatum, thalami, mesencephalon, pons, cerebellar vermis, and medulla, and to a lesser degree in the perirolandic cortex, mesial occipital cortex and hippocampal area.
The global CBF was mean 17.8 ml/100g/min. The mean rCBF in periventricular unmyelinated white matter and thalami were 10.3 ml/100g/min and 31.3 ml/100g/min, respectively. The average white matter/thalamic ratio CBF was 0.36.
Conclusions: Minimally invasive 15O-water PET with very small radiation dose yielded expected values of global and regional CBF using a non-invasive IDIF. The method may be used for quantitative rCBF measurements in unsedated newborn infants for clinical research purposes.
Reference
1Andersen JB, J Cereb Blood Flow Metab, 2015
PS02-090
Poster Viewing Session II
Early uptake Amyloid PET imaging correlates strongly with cerebral blood flow based on arterial spin labeling MRI: a simultaneous PET/MRI study
G. Zaharchuk1, A. Fan1, P. Gulaka1, J. Guo1, K. Poston1, M. Greicius1, S. Sha1, M. Vasanawala1 and M. Zeineh1
1Stanford University, Stanford, United States
Abstract
Objectives: Cerebral blood flow (CBF) is a fundamental marker of tissue health and aids in the diagnosis of dementia. We sought to determine whether early uptake amyloid PET imaging could offer information about CBF, using arterial spin labeling (ASL) in a simultaneous PET/MRI study.
Methods: PET/MRI (Signa, GE Healthcare) was performed in 14 subjects (5 healthy subjects, 2 Alzheimer's disease, and 7 Parkinson's disease; mean age 66 ± 9 yrs). Dynamic images of 314 ± 34 mBq 18F-florbetaben (314 ± 34mBq, Neuraceq, Piramal Imaging, Berlin, Germany) were acquired with pseudocontinuous ASL (TR/TE 7366/10 ms, TL/PLD 3000/3000 ms). A long-label long-delay ASL sequence was acquired to minimize the effects of prolonged transit time. Correlation was performed between the relative amyloid uptake during either early (0–5 min) and late (90–110 min) time periods and ASL in 20 ROI's per subject.
Results: Figure shows an example of early and late 18F-florbetaben uptake with ASL. 93% of ASL images were of adequate quality and were included in the study. There was a strong correlation between early amyloid uptake and ASL CBF (R2 = 0.70 ± 0.15, p< 0.05). There was no correlation between late amyloid uptake and ASL CBF (R2 = 0.29 ± 0.31, p > 0.05).
Discussion: Using simultaneous PET/MRI, we have shown that we can estimate relative CBF from early-uptake amyloid imaging. Because CBF and glucose metabolism are linked, this approach allows imaging of two important dementia biomarkers during the same scan, improving patient convenience and reducing dose. We also show that pseudocontinuous ASL has improved quality compared with prior pulsed ASL PET/MRI studies1,2. This dual biomarker approach broadens the value of amyloid imaging for the diagnosis and monitoring of dementia.
Late and early amyloid PET/MRI
References
1Werner et al., Proc SNM 2016; 514
2Barthel et al., Proc SNM 2016; 235
PS02-091
Poster Viewing Session II
INDOPET Project: Impact of Indomethacin on cerebral metabolism and blood flow in patients with severe traumatic brain injury and refractory intracranial hypertension (PET 15O study)
C. Puppo1, L. Moraes2, J. De Los Santos3, M. Garaza3, G. Huelmo3 and A. Biestro2
1Universidad de la República, Uruguay, Emergency Department, Hospital de Clínicas de Montevideo, Montevideo, Uruguay
2Universidad de la República, Uruguay, Intensive Care Department, Hospital de Clínicas de Montevideo, Montevideo, Uruguay
3Universidad de la República, Uruguay, Hospital de Clínicas de Montevideo, Montevideo, Uruguay
Abstract
Severe traumatic brain injury (sTBI) is a leading cause of death and disability, posing a huge public health challenge at a vast number of countries in the world regardless of their economic situation. Intracranial Hypertension (ICH) is the most important modifiable predictor of poor outcome after TBI. Its control measures included in the guidelines have limited efficacy and frequent adverse effects. In 20 years of use, we know that indomethacin lowers ICH through microvascular vasoconstriction, decreased CBV and CBF. It is cheap, and, -fundamental difference with other measures-, does not generate hemodynamic disturbances or sedation. Despite its effectiveness and no evident signs of clinical or imaging ischemic damage associated with its use, it has not found wide global diffusion because an existing suspicion that it could generate ischemic damage. Current circumstances in our hospital are perfect to solve this problem: a research group experienced in indomethacin use in sTBI and a center, with the “gold standard” technology to study and detect cerebral ischemia (PET-CT). This study, if positive, will be the initial step to a Latin American multicenter trial to incorporate the drug as an effective and safe first therapeutic tier.
Objectives: To study (using PET-CT-15O) changes associated with indomethacin use in ICH control in severe TBI patients. We will measure cerebral blood flow (CBF) and oxygen extraction fraction (OEF).
Methodology: Two consecutive steps: 1) Development of Oxygen 15 PET methodology to detect brain ischemic damage (previously nonexistent in Latin America). 2) Its Implementation for evaluation of cerebral metabolism and hemodynamics in patients with first tier measures refractory ICH sTBI, pre and intra indomethacin. Each patient will be his or her own control before (baseline) and during drug infusion.
Expected results: demonstration that indomethacin lowers ICP and generates no ischemic damage, by decreasing CBF and simultaneously increasing OEF.
PS02-092
Poster Viewing Session II
Simultaneous measurement of cerebral blood flow with pseudo continuous arterial spin labeling, phase contrast mapping and 15O-H2O PET in a hybrid PET/MR system. Preliminary results
O. Puig1, O. Henriksen1, U. Lindberg2, E. Rostrup2, A.E. Hansen2, H. Larsson2 and I. Law2
1Department of Clinical Physiology, Nuclear Medicine and PET, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
2Clinical Physiology, Nuclear Medicine and PET, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
Abstract
Objective: MRI techniques such as arterial spin labelling (ASL) and phase contrast mapping (PCM) provide non-invasive approaches for measuring regional and global CBF, respectively. However, the accuracy of these methods is not established. The aim of the study is to validate our implementations of ASL and PCM CBF measurements against simultaneously acquired 15O-H2O PET CBF measurements in healthy subjects in various perfusion states using a hybrid PET/MR system.
Methods: Simultaneous PET, ASL and PCM measurements were performed in 3 healthy volunteers. In each volunteer duplicate measurements of each method were performed in during rest, hypoperfusion (hyperventilation) and hyperperfusion (post-acetazolamide). For PET CBF approx. 500 MBq of 15O-H2O was administered and arterial blood sampling was obtained. Kinetic modelling was performed in PMOD (1-tissue 2 compartment model). A multi TI pseudo-continuous ASL sequence was applied and analyzed using FSL BASIL and segmented using a T1 MRI derived brain mask. Pulse-triggered PCM flow measurements of the internal carotid and vertebral arteries were summed and normalized to brain volume.
Results: Examples of CBF maps and correlation of global CBF values are presented in Fig1. Overall highly significant positive and linear correlations of both ASL (R2 = 0.88, p< 0.001) and PCM (R2 = 0.63, p< 0.001) with PET across states were observed. PCM yielded higher CBF values compared to PET in all states, whereas ASL differed only during hyperperfusion.
Conclusion: These preliminary results demonstrated the ability of both PCM and ASL to obtain absolute CBF in fair agreement with PET, but also the potential of hybrid PET/MR systems for simultaneous validation of quantitative MRI CBF measurements. The study is ongoing and additional data and analysis will be presented.
PS02-093
Poster Viewing Session II
Assessment of inter-individual and regional variability of the coupling of cerebral blood flow and oxygen metabolism
O. Henriksen1, E. Rostrup1, K. Vang2, A. Gjedde3, I. Law1,3 and J. Aanerud2
1Rigshospitalet, Dept. of Clinical Physiology, Nuclear Medicine and PET, Copenhagen, Denmark
2Århus University Hospital, Dept. of Nuclear Medicine and PET Centre, Århus, Denmark
3University of Copenhagen, Copenhagen, Denmark
Abstract
Objective: Large between subject variability of cerebral blood flow (CBF) has been demonstrated, but the basis of this variability is not established1,2. The aim of the present analysis was to assess the regional and inter-individual interdependency of CBF and metabolic rate of oxygen (CMRO2) from previously published data sets3.
Methods: Corresponding PET measurements of CBF and CMRO2 were obtained in 51 healthy volunteers (21 -73 years old). Values of CBF and CMRO2 in VOIs corresponding to global grey matter (gGM), white matter, striate, primary sensory-motor cortex and cortex of each lobe were obtained and oxygen extraction fraction (OEF) was calculated for each VOI. Linear regression was used for analysis of inter-individual correlations of CBF and CMRO2 and mixed linear models for assessment of variability and regional effects. Age, hemoglobin and PaCO2 were entered as covariates.
Results: CBF and CMRO2 were positively correlated in gGM and in all VOI's (partial R2 0.34–0.43 and p< 0.001 for all, adjusted for covariates). Inter-individual variability of OEF (CV 16.9%) was higher than those of both CBF (12.2%) and CMRO2 (12.3%), and including covariates had only minimal influence on estimates of variability.
[Global GM and regional of CBF, CMRO2 and OEF]
Compared to gGM lower OEF was observed in frontal cortex and higher OEF in parietal, sensory-motor and occipital cortex (p≤0.05 for all). Adding an interaction term increasing age was associated with decreasing OEF (p = 0.024) in occipital cortex only.
Global GM and regional of CBF, CMRO2 and OEF
Conclusions: The present analysis shows large between-subject variability and smaller, but significant regional differences in OEF that cannot be attributed to the most relevant covariates. The findings suggest that the large variability of CBF measurements must reflect other factors than metabolic demands, or methodological factors prohibiting such analysis.
Imaging neuroinflammation in patients with multiple sclerosis using [18F]FEMPA-PET: A pilot study
L. Vivash1,2, R.J. Hicks3,4, D. Krenus5, T.J. Kilpatrick1,6 and T.J. O'Brien1,4
1Royal Melbourne Hospital, Neurology, Parkville, Australia
2University of Melbourne, Melbourne Brain Centre, Department of Medicine, Melbourne, Australia
3Peter MacCallum Cancer Centre, Centre for Cancer Imaging, Melbourne, Australia
4University of Melbourne, Medicine, Melbourne, Australia
5Cyclotek Pty Ltd, Melbourne, Australia
6University of Melbourne, Melbourne Neuroscience Institute, Melbourne, Australia
Abstract
Objective: Activated microglia are known to play a role in the pathogenesis of multiple sclerosis (MS), however, there have been considerable barriers to imaging microglia in living patients. This study reports the use of [18F]FEMPA-PET for imaging the translocator protein (TSPO), as a biomarker of activated microglia, in patients with multiple sclerosis.
Methods: Five patients with secondary progressive MS (SPMS, 51–68 years, 2 male, MSSS 4-6) and four healthy controls (35–53 years, 3 male, MSSS 0) underwent a 60-minute dynamic [18F]FEMPA PET. Participants also underwent a T1-weighted MRI, T2-weighted MRI and gadolinium-enhanced sequences.
[18F]FEMPA SUV images were produced as a simple method of quantifying neuroinflammation. The simplified reference tissue model was used to generate quantifiable images of [18F]FEMPA BPND images using the cerebellum as the reference region. ROI analysis was performed on grey matter (GM), white matter (WM) and selected subcortical structures.
Results: Peak uptake of [18F]FEMPA occurred 2–5 minutes post-injection. Peak GM SUV was the same in patients and controls (1.56 vs 1.67). Mean GM SUV for 0–60 minute images was similar in patients and controls (0.88 vs 0.95). No difference was observed in the WM of patients and controls either (0.76 vs 0.88).
GM BPND was similar in patients and controls (0.12 vs 0.11), however, WM BPND was higher in patients than controls (0.10 vs 0.06).
Visual inspection of raw scans could not detect any specific increases in radiotracer uptake that may indicate disease, but BPND images showed increased BPND co-localised with white matter lesions.
Conclusions: PET imaging with [18F]FEMPA identifies increased TSPO binding in the GM of patients with SPMS. SUV can be used to detect global microglial activation burden in the WM of patients, but quantification of BPND provides more information for the localisation of specific abnormalities.
PS02-096
Poster Viewing Session II
Effective connectivity in the default mode network is distinctively disrupted in Alzheimer's disease
M. Scherr1, L. Utz2,3, T. Grimmer1, A. Drzezga4, C. Sorg2 and V. Riedl2
1Technische Universität München (TUM), Psychiatry, München, Germany
2Technische Universität München (TUM), TUM-Neuroimaging Center, München, Germany
3Technische Universität München (TUM), Institute for Advanced Studies (IAS), München, Germany
4Universitätsklinikum Köln, Köln, Germany
Abstract
Alzheimer's disease (AD) is characterized by progressive accumulation of misfolded proteins in the human brain predominantly affecting the default mode network (DMN). Molecular models suggest that spreading of neuropathology relies on the directionality of signaling or connectivity in the brain. However, in-vivo evidence about directional signaling in patients is still missing. We recently introduced metabolic connectivity mapping (MCM) as a novel measure of directional signaling, or effective connectivity (EC). MCM is a voxel measure integrating simultaneously acquired functional magnetic resonance imaging (fMRI) and 18F-fluoro-deoxy-glucose (FDG) positron-emission-tomography (PET) data. Using MCM, we first identified EC in the DMN of healthy subjects and then tested whether certain pathways are disrupted in AD. We found two distinct subnetworks in the DMN: an anterior (hippocampus-medial prefrontal cortex) and a posterior (medio-lateral parietal cortex) system. The only link between both systems was unilateral EC from medial prefrontal into medial parietal cortex. Patients had a similar network configuration yet strongly reduced EC into the medial parietal system and absent input from hippocampus into medial frontal cortex. In a unified model explaining cognitive deficits in patients with functional imaging measures, we found that the integrated measure of EC best predicted cognitive impairment compared to fMRI or FDG-PET measures alone. Together, we found systems-level disruptions of directional signaling in anterior and posterior parts of the DMN, which may inform current theories about downstream and upstream spreading of neuropathology in AD.
EC_AD
PS02-097
Poster Viewing Session II
Dopaminergic neuronal oxidative stress is increased with disease severity in patients with Parkinson's disease: A study with PET and SPECT
M. Ikawa1, H. Okazawa2, H. Neishi3, T. Tsujikawa2, K. Kikuta3, Y. Nakamoto1 and M. Yoneda2,4
1University of Fukui, Second Department of Internal Medicine (Neurology), Fukui, Japan
2University of Fukui, Biomedical Imaging Research Center, Fukui, Japan
3University of Fukui, Department of Neurosurgery, Fukui, Japan
4Fukui Prefectural University, Faculty of Nursing and Social Welfare Science, Fukui, Japan
Abstract
Objective: Oxidative stress is assumed to contribute to promoting the dopaminergic neurodegeneration in Parkinson's disease (PD). In fact, our previous study using positron emission tomography (PET) with 62Cu-ATSM, which allows to image oxidative stress based on mitochondrial dysfunction, demonstrated greater striatal uptake that increased with the disease severity in patients with PD than healthy controls. However, the correlation between the uptake and severity was slightly weak, probably because a decrease in striatal neurons may have offset the total neuronal uptake. This study sought to evaluate dopaminergic neuronal oxidative stress and its relationship with the disease severity in patients with PD using 62Cu-ATSM PET and single-photon emission computed tomography (SPECT) with 123I-FP-CIT (dopamine transporter imaging).
Methods: Nine patients with PD (6M/3F, 67.3 ± 7.1 years old) were studied with 62Cu-ATSM PET and 123I-FP-CIT SPECT. Standardized uptake values (SUVs) were obtained from the delayed phase of dynamic 62Cu-ATSM PET data, and striatum-to-cerebellum SUV ratio (SUVR) was calculated. 62Cu-ATSM SUVR was corrected for striatal specific binding ratio (SBR) values of 123I-FP-CIT (SUVR/SBR ratio) to correct the effect of dopaminergic neuronal loss on evaluating oxidative stress.
Results:62Cu-ATSM SUVR without correction was not significantly correlated with disease severity estimated by the Unified Parkinson's Disease Rating Scale (UPDRS) scores or 123I-FP-CIT SBR. In contrast, the SUVR/SBR ratio showed significant correlations with the UPDRS total (r = 0.85, p < 0.005) and motor scores (r = 0.83, p < 0.01), and 123I-FP-CIT SBR (r = −1.00, p < 0.001).
Conclusions: Oxidative stress in the remaining striatal dopaminergic neurons estimated by SUVR/SBR ratio was increased with disease severity in patients with PD, which suggests that oxidative stress contributes to promoting the neurodegenerative process in advanced PD. 62Cu-ATSM PET with 123I-FP-CIT SPECT correction would be a promising tool to evaluate dopaminergic neuronal oxidative stress in patients with PD.
PS02-098
Poster Viewing Session II
Sigma-1 receptor (S1R) radioligand uptake in chronic pain
T. Hjørnevik1,2,3, P.W. Cipriano1, B. Shen1, J.H. Park1, P.K. Gulaka1, C.M. McCurdy4, F.T. Chin1 and S. Biswal1
1Stanford University, Department of Radiology, Stanford, United States
2Oslo University Hospital, The Intervention Centre, Oslo, Norway
3The Norwegian Medical Cyclotron Centre, Oslo, Norway
4The University of Mississippi, Department of BioMolecular Sciences, University, United States
Abstract
Objectives: SIRs play an important role in pain. We investigated the normal distribution of a novel SIR-selective radioligand in the human brain of asymptomatic volunteers and chronic pain sufferers.
Methods: Nine healthy controls (HC; five female, four male; 34.4 ± 6.9 years) and seven patients (five female, two male; 40.0 ± 16.6 years) diagnosed with Complex Regional Pain Syndrom (CRPS) were imaged for 10 minutes with the novel PET tracer [18F]FTC-1461 on a simultaneous PET/MR scanner (SIGNA, GE Healthcare). Reconstructed image data (in standardized uptake values (SUVs)) were spatially normalized to Montreal Neurological Institute (MNI) space in PMOD 3.7. Regional normal uptake of [18F]FTC-146 was quantified using predefined atlas regions2, and voxel-based group analysis (HC vs. CRPS) was performed in SPM12.
Results: In HCs, high uptake of [18F]FTC-146 was observed in the cingulate cortex and thalamus, moderate uptake in the insula and caudate nucleus, and low uptake in white matter (Figure 1A). Five out of seven CRPS patients reported primarily right-sided pain symptoms. Significantly decreased uptake (t-test; cluster >50; p< 0.01) of [18F]FTC-146 in the CRPS group was observed in the right thalamus, right caudate nucleus, right parietal cortex, right cingulate cortex, left brainstem, left insula and frontal cortices (Fig. 1B).
[18F]FTC-146 uptake in HCs and CRPS patients
Conclusions: These early results indicate that the [18F]FTC-146 binding pattern is altered in patients with chronic pain compared to controls. Additional participants are currently being recruited to further validate our findings.
References
1 Shen et al., submitted
2Hammers et al., Hum Brain Mapp (2003)
PS02-099
Poster Viewing Session II
Pharmacological PET/MRI evidences of agonist-induced µ-Opioid receptor desensitization
H.-Y. Wey1, M. Placzek1,2, J. Hooker1, B. Rosen1 and J. Mandeville1
1Massachusetts General Hospital, Harvard Medical School, Athinoula A. Martinos Center for Biomedical Imaging, Charlestown, United States
2McLean Hospital, Harvard Medical School, Belmont, United States
Abstract
Objectives: µ-Opioid receptor (MOR) agonists-induced receptor desensitization and the resulting development of opioid tolerance have contributing to the increasing opioid epidemic (1). We recently demonstrated the potential use of PET/MRI to estimate agonist-induced MOR desensitization in vivo (2). The purpose of this study is to provide additional evidences for the notion that increase PET binding potentials could be an in vivo biomarker for MOR desensitization (2,3).
Methods: PET/MRI images were acquired from a macaque using a 3T Siemens BrainPET with a µ-opioid selective radiotracer, [11C]carfentanil (∼8 mCi; S.A.: ∼3 mCi/nmol), given as bolus-infusion. PET data were binned into 1-min frames. CBV-fMRI data were obtained following an iron oxide injection. Remifentanil (10 µg/kg), a short-acting MOR full agonist (2 min blood half life), and buprenorphine (0.3 mg/kg), a MOR partial agonist, were given intravenously at 35 min post radiotracer administration. PET data was analyzed using the simplified reference tissue model(4). A gamma-variant function was used to model the PET and fMRI temporal response to drug challenge.
Results: Baseline TACs show that PET signal reached a steady-state with bolus/infusion of [11C]carfentanil (Fig 1)(2). TACs of the reference tissue are comparable between baseline and drug-challenging scans. Apparent increases in TACs in high-binding regions following remifentanil injection (Fig 1) was observed, suggesting a potential increase in receptor affinity. However, buprenorphine, a MOR partial agonist known not to desensitize MORs, caused drug-radiotracer competitions (Fig 1) and resulting in a reduction in BPND.
Time activity curves before and after drug.
Conclusions: We demonstrated an increase in PET BPND potentially reflects agonist-induced MOR desensitization using pharmacological agents with known effects on MORs.
References
(1) Williams JT, et al. Pharmacological Reviews. 2013.
(2) Wey HY, et al. NeuroReceptor Mapping. 2016.
(3) Birdsong WT, et al. J Neurosci. 2013.
(4) Lammertsma AA, et al. NeuroImage. 1996.
PS02-100
Poster Viewing Session II
Binding of a metabotropic glutamate receptor subtype 5 radioligand, (E)-[11C]ABP688, in human brains assessed by test-retest PET scans
M. Kubota1, Y. Kimura1,2, M. Ichise1, C. Seki1, K. Takahata1, S. Kitamura1, S. Moriguchi1, T. Ishii1, M.-R. Zhang3, M. Higuchi1 and T. Suhara1
1National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, Department of Functional Brain Imaging Research, Chiba, Japan
2Center for Development of Advanced Medicine for Dementia, National Center for Geriatrics and Gerontology, Department of Clinical and Experimental Neuroimaging, Obu, Japan
3National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, Department of Radiopharmaceutics Development, Chiba, Japan
Abstract
Previous human PET studies with [11C]ABP688 and [18F]FPEB have demonstrated increased metabotropic glutamate receptor subtype 5 (mGluR5) binding in retest versus test scans on the same day (DeLorenzo et al., 2011, 2016). Several factors including circadian rhythm and stress are thought to account for this increase. The current study aimed to examine test-retest differences in binding of (E)-[11C]ABP688, which has a higher affinity towards mGluR5 than does [11C]ABP688.
Eleven healthy young males underwent test-retest PET scans on the same day using a Biograph mCT scanner with fasting between the two scans. Sixty-minute scanning was conducted after an intravenous bolus injection of (E)-[11C]ABP688 (440 MBq). Arterial blood was sampled from 6 subjects.
mGluR5 binding was evaluated by estimating total distribution volume (VT) (Logan plot) for subjects with arterial data. For all subjects, binding potential (BPND) was estimated using a reference tissue model (MRTM2) with the cerebellar cortex as reference. Additionally, VT* (VT normalized by cerebellar K1), which does not require arterial data, was estimated. Subsequently, test-retest differences in these mGluR5 binding parameters were investigated. Test-retest differences in BPND and VT* were also compared between subgroups with and without arterial blood sampling to assess potential stress effects.
There were significant decreases in VT and VT*, and a trend of reduced BPND across regions in retest scans relative to test scans. For example, average putaminal VT in retest scans was 2.98 and was 20.18% lower than that in test scans. Arterial blood sampling did not affect the test-retest differences in BPND or VT*.
Contrary to previous reports, the current results demonstrated decreased mGluR5 binding in retest scans, regardless of arterial sampling. This discrepancy is yet to be mechanistically explained, and physiological factors potentially influencing mGluR5 states, such as fasting, are being investigated.
PS02-101
Poster Viewing Session II
The neurobiology of treatment resistant and responsive schizophrenia: an [18F]DOPA PET study
E. Kim1, O. Howes2 and J.S. Kwon1
1Seoul National University, Seoul, Korea, Republic of
2Institute of Psychiatry, Psychology and Neuroscience, King's College, London, United Kingdom
Abstract
Some patients with schizophrenia show poor response to first-line antipsychotic treatments and this is termed treatment resistant schizophrenia. The differential response to first-line antipsychotic drugs may reflect a different underlying neurobiology. Indeed, a previous study found dopamine synthesis capacity was significantly lower in patients with treatment resistant schizophrenia. However, in this study, the treatment resistant patients were highly symptomatic whilst the responsive patients showed no or minimal symptoms. The study could not distinguish whether this was a trait effect or reflected the difference in symptom levels. Thus we aimed to test whether dopaminergic function is altered in patients with a history of treatment resistance to first-line drugs relative to treatment responders when both groups are matched for symptom severity levels by recruiting treatment resistant patients currently showed low symptom severity with the clozapine treatment.
Healthy controls(n = 12), patients with treatment resistant schizophrenia(n = 12) who had responded to clozapine and patients who had responded to first-line antipsychotic drugs(n = 12) were recruited. Participants were matched for age and sex, and symptomatic severity level in patient groups. Participants' dopamine synthesis capacity was measured by using [18F]DOPA PET.
We found that patients with treatment resistant schizophrenia show lower dopamine synthesis capacity than patients who have responded to first-line treatment(Cohen's d = 0.9191(whole striatum), 0.7781(Associative striatum), 1.0344(Limbic striatum), 1.0189(Sensorimotor striatum) in line with the hypothesis that the dopaminergic function is linked to treatment response.
This suggests that a different neurobiology may underlie treatment resistant schizophrenia and that dopamine synthesis capacity may be a useful biomarker to predict treatment responsiveness.
PS02-102
Poster Viewing Session II
Reduced TSPO levels in drug-naïve first episode psychosis patients as measured using PET and [11C]PBR28
K. Collste1, P. Plavén-Sigray1, H. Fatouros-Bergman1, P. Victorsson1, M. Schain1,2, A. Forsberg1, N. Amini1, S. Aeinehband3, S. Erhardt4, C. Halldin1, L. Flyckt1, L. Farde1,5 and S. Cervenka1
1Karolinska Institute, Department of Clinical Neuroscience, Centre for Psychiatry Research, Stockholm, Sweden
2Columbia University, Department of Psychiatry, Molecular Imaging and Neuropathology Division, New York, United States
3Karolinska Institute, Department of Clinical Neuroscience, Neuroimmunology Unit, Stockholm, Sweden
4Karolinska Institute, Department of Physiology and Pharmacology, Stockholm, Sweden
5AstraZeneca Translational Science Center at Karolinska Institutet, Stockholm, Sweden
Abstract
Objectives: Positron Emission Tomography (PET) studies of the translocator protein (TSPO), a marker for glial activation, have yielded conflicting results in schizophrenia. Very recently, investigations using second generation TSPO radioligands have shown increases, no differences or trend-level decreases in binding(1–3). Importantly, most patients were on antipsychotics, limiting the conclusions that can be drawn.
Methods: We examined 16 drug-naϊve, first episode psychosis patients (FEP) and 16 healthy controls using PET and [11C]PBR28. Gray matter (GM) Volume of Distribution (VT), derived from the two-tissue compartment model (2TCM) with arterial input function, was the main outcome measure. To enable comparisons with a previous publication using [11C]PBR28 (1), data were also analyzed using the 2TCM-1K model (4). In addition, DVRs, the ratio between GM VT and whole brain (WB) VT for both 2TCM and 2TCM-1K, were calculated. Group differences in TSPO binding were analyzed using univariate independent samples ANCOVAs with TSPO genotype and gender as covariates.
Results: Significant reduction of [11C]PBR28 VT was seen in patients compared to controls in GM (F = 6.19, df = 1,28, p = 0.019). 2TCM-1K produced similar results, whereas no difference was found when analyzing DVR values derived from either 2TCM or 2TCM-1K.
Conclusions: A decrease in TSPO binding in antipsychotic-naïve FEP was shown, indicating reduced numbers or altered function of immune cells in brain in early psychosis. Further studies combining brain imaging with pro- and anti-inflammatory immune markers are needed to clarify the role of the immune system in different stages of schizophrenia.
References
1. P. S. Bloomfield et al., Am. J. Psychiatry. 2016; 173(1):44–522.
2. J. M. Coughlin et al., Transl Psychiatry. 2016; Apr 12.
3. S. Hafizi et al., Am. J. Psychiatry, 2016; Sep 9.
4. G. Rizzo et al., Journal of Cerebral Blood Flow & Metabolism. 2014; 34(6):1060–1069
PS02-103
Poster Viewing Session II
Preclinical PET studies on muscarinic acetylcholine receptor occupancy by a antimuscarinic agent, solifenacin using 11C-(+3)N-methyl-3-piperidyl benzilate
1Graduate School of Convergence Science and Technology, Seoul National University, Department of Transdisciplinary Studies, Seoul, Korea, Republic of
2Seoul National University Bundang Hospital, Seoul National University College of Medicine, Department of Nuclear Medicine, Seoul, Korea, Republic of
3Dong-A ST Research Center, Yongin, Korea, Republic of
4Advanced Institutes of Convergence Technology, Suwon, Korea, Republic of
Abstract
Muscarinic acetylcholine receptor (mAChR) is implicated in various central and peripheral nervous system disorders. And 11C-(+3)N-methyl-3-piperidyl benzilate ([11C](+)3-NMPB) is a recently developed PET tracer which has preferential binding kinetics to M1 and M2 subtypes of mAChR. In the present study, we investigated changes in mAChR occupancy by a widely used antimuscarinic agent, solifenacin using [11C](+)3-NMPB and PET. We also evaluated a semi-quantification method optimized for simplified preclinical [11C](+)3-NMPB PET studies.
Dynamic [11C](+)3-NMPB PET studies were performed in mice with different doses of solifenacin (vehicle, 3 and 10 mg/kg, i.v.). BPND of [11C](+)3-NMPB was estimated using Logan graphical analysis with cerebellar reference tissue input function, and the percent difference in BPND (or occupancy) in various cortical and subcortical regions between dose conditions were calculated compared to the vehicle. Equilibrium area under the curve (AUC) ratio between target and reference tissue were also calculated and compared with BPND. Finally, a set of statistical tests were performed to assess the collected data.
At the vehicle condition, [11C](+)3-NMPB distribution in the cortical and subcortical regions were well visualized consistently with the known distribution of mAChR with the greatest BPND value in the striatum (mean ± SEM = 2.6 ± 0.2). However, the BPND values were decreased after the administration of solifenacin in a dose-dependent manner (F(2,30) = 131.17, P < 0.01). The hippocampus showed the greatest changes in mAChR occupancy (19.3–70.9% after 3 and 10 mg/kg solifenacin administration, respectively). Excellent correlation between varying levels of BPND and AUC ratio per solifenacin doses were found the across the regions.
Data demonstrated preclinical efficacy of solifenacin of altering mAChR function in a dose-dependent manner. Also the results suggest that semi-quantification of [11C](+)3-NMPB binding with equilibrium AUC ratio method may extend the application of [11C](+)3-NMPB PET technique to assess efficacy of various mAChR-targeting drugs.
PS02-104
Poster Viewing Session II
Quantitative PET analysis of subregional striatal dopaminergic neurodegeneration in the MPTP primate model of Parkinson's disease
S.H. Park1, H.S. Park1,2, B.S. Kim3, S.M. Lim4, S. Yang5, K.-T. Chang6,7, S.-R. Lee6,7, Y. Lee6 and S.E. Kim1,2,8
1Graduate School of Convergence Science and Technology, Seoul National University, Department of Transdisciplinary Studies, Seoul, Korea, Republic of
2Seoul National University Bundang Hospital, Seoul National University College of Medicine, Department of Nuclear Medicine, Seoul, Korea, Republic of
3Ewha Womans University School of Medicine, Department of Nuclear Medicine, Seoul, Korea, Republic of
4Ewha Womans University School of Medicine, Department of Radiology, Seoul, Korea, Republic of
5Ewha Institute of Convergence Medicine, Ewha Womans University, Seoul, Korea, Republic of
6National Primate Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Cheongju, Korea, Republic of
7University of Science & Technology, National Primate Research Center, KRIBB, Cheongju, Korea, Republic of
8Advanced Institutes of Convergence Technology, Suwon, Korea, Republic of
Abstract
MPTP is a neurotoxin with high specificity for the dopamine (DA) neurons of the nigrostriatal pathway of humans and non-human primates. In the present study, we performed quantitative PET studies using 18F-N-3-fluoropropyl-2-b-carboxymethoxy-3-b-(4-iodophenyl)nortropane ([18F]FP-CIT) in an attempt to characterize DA-ergic neurodegradation in a MPTP primate model of PD.
Total six male cynomolgus monkeys underwent repeatedly 90-min dynamic [18F]FP-CIT PET scans before and one month after i.m. MPTP injection resulting in bilateral effects. Time-activity curves (TAC) of the [18F]FP-CIT distribution in subregions of the striatum, midbrain and the cerebellum were generated using spatially normalized PET images. The net influx rate constant (Ki [min−1]) of the radiotracer was estimated with Patlak graphical analysis method for those TACs. The cerebellum was used as the reference tissue. Changes (%) in Ki before and 1-month after the MPTP treatment were calculated and statistically tested. Finally, correlation analysis was performed between level of inter-individual Ki changes in the subregions of the striatum and those in the midbrain.
Subregional striatal DA-ergic neuronal degradation or decreased Ki by i.m. MPTP injection were substantial (F(1, 24) = 177.1, P < 0.05), while the level of the changes in Ki were distinctive between subregions of striatum (F(4, 20) = 9.542, P < 0.05). Interestingly, level of decreased Ki in the midbrain was relatively marginal, possibly due to underestimated Ki. The ventral putamen showed the greatest changes ([mean ± SEM] = −85.4 ± 6.8%change). Level of changes in midbrain Ki was significantly correlated with those of the anterior and posterior putamen (Pearson's r = 0.960 and 0.954, respectively), and anterior caudate (Pearson's r = 0.904).
These results demonstrated distinctive subregional striatal DA-ergic neurodegradation by i.m. MPTP injection in non-human primate model of PD. Further study investigating time-course of Ki changes should help understand pathophysiologic details of this PD model.
PS02-105
Poster Viewing Session II
Simultaneous PET/fMRI imaging of the serotonin receptor system: the 5-HT4 receptor subtype
E. Verwer1, D.W. Wooten1, J. Mandeville2, R. Neelamegam1, D.L. Yokell1, G. El Fakhri1, N.M. Alpert1 and M.D. Normandin1
1Massachusetts General Hospital & Harvard Medical School, Gordon Center for Medical Imaging, Boston, United States
2Massachusetts General Hospital & Harvard Medical School, Martinos Center for Biomedical Imaging, Boston, United States
Abstract
Objectives: Simultaneous PET/fMRI allows concurrent measurement of receptor occupancy using PET and changes in cerebral blood volume (ΔCBV) using fMRI. In previous work we demonstrated this for the dopaminergic system and for serotonergic 5-HT1A and 5-HT2A receptor subtypes, where we found that ΔCBV measures for targeted agonist/antagonist drugs were consistent with the excitatory/inhibitory properties of the targeted receptor subtypes. We now extend upon this work by measuring receptor occupancy and functional responses from agonist and antagonist drugs targeting the excitatory 5-HT4 receptor.
Methods: Two rhesus macaques were scanned 9 times using a simultaneous PET/MR (Siemens Trio with BrainPET insert). PET was used to determine striatal 5-HT4 receptor occupancy by the 5-HT4 targeted drugs RS67333 (agonist) and SB207145 (antagonist), with baseline and competition scans acquired following bolus injection of the 5-HT4 radiotracer 11C-SB207145 (where applicable with coinjection of the drug). Simultaneously, fMRI with iron-oxide enhanced echo planar imaging was used to measure ΔCBV. For antagonist SB207145, ΔCBV was also measured at 'elevated 5-HT' conditions, as achieved by administering fenfluramine 30 min prior to administering the antagonist (5mg/kg i.v. infused over 5 min). Elevating 5-HT increases the amount of endogenous 5-HT4 signaling that can be silenced by the exogenous 5-HT4 antagonists and thus enhances the drug's indirect effects. In addition, fenfluramine only fMRI scans were acquired for comparison.
Results: No measurable ΔCBV was observed with fMRI for either agonist RS67333 or antagonist SB207145, even at doses that resulted in >90% 5-HT4 striatal receptor occupancy (0.2 mg/kg and 0.25 mg/kg, respectively), and even under 'elevated 5-HT' conditions.
Conclusions: In contrast to the 5-HT1A and 5-HT2A receptor subtypes, drugs targeting the 5-HT4 receptor did not elicit a measurable fMRI response. Hence, the 5-HT4 receptor can potentially be omitted from consideration in the unified PET/fMRI model of pharmacologic action of the serotonergic system.
Support: R01MH100350
PS02-106
Poster Viewing Session II
Serotonin 5HT1A receptor binding and self-transcendence in healthy control subjects - a replication study using Bayesian inference
G. Griffioen1,2, J. Borg1, G.J. Matheson1,3, S. Cervenka1,3 and L. Farde3,4
1Karolinska Institute, Centre for Psychiatry Research, Department of Clinical Neuroscience, Stockholm, Sweden
2Capio, Psychiatry, Nacka, Sweden
3Stockholm Brain Institute, Stockholm, Sweden
4Karolinska Institute, AstraZeneca Translational Science Center, Stockholm, Sweden
Abstract
Objective: A putative relationship between markers for the serotonin system and the personality scale self-transcendence and its subscale spiritual acceptance has been demonstrated both in PET of 5-HT1A receptor binding in healthy control subjects1 and in genetic studies2. The results could however not be replicated in a subsequent PET study at an independent centre3. In this study, we performed a replication of our original study in a larger sample using Bayesian inference to evaluate relative evidence both for and against the hypothesis.
Methods: Regional 5-HT1A receptor binding was examined in 50 healthy male subjects by PET and the radioligand [11C]WAY100635. All subjects filled in the Temperament and Character Inventory (TCI). The correlations were examined by calculation of linear regression Bayes factors (BFs) and replication BFs.
Results: There were no significant correlations between 5-HT1A receptor binding and self-transcendence. In contrast, five of six replication BFs provided moderate to strong evidence for no association between 5-HT1A availability and self-transcendence, while the remaining BF was uninformative.
Conclusion: We could not replicate our previous findings. The Bayesian analysis rather provided evidence for a lack of correlation between 5-HT1A receptor binding and self-transcendence. Further research should focus on whether other components of the serotonin system may be related to self-transcendence. This study also illustrates how Bayesian inference allows for greater flexibility and more informative conclusions than traditional p-values, and offers practical advantages for analysis of future molecular imaging studies4.
References
1. Borg et al. Am. J. Psychiatry (2003).
2. Lorenzi et al. Am. J. Med. Genet. B. Neuropsychiatr. Genet. (2005).
3. Karlsson et al. Mol. Psychiatry (2011).
4. Wagenmakers et al. Curr. Dir. Psychol. Sci. (2016).
PS02-107
Poster Viewing Session II
Divergent levodopa mediated modulation of motor- and cognitive-related network activity in Parkinson's disease: a FDG PET, ASL MRI and fMRI study at resting state
Y. Ma1, S. Peng1, A. Vo1, P. Spetsieris1, V. Dhawan1 and D. Eidelberg1
1The Feinstein Institute for Medical Research, Center for Neurosciences, Manhasset, United States
Abstract
Objectives: Parkinson's disease (PD) is characterized by motor- and cognition-related metabolic brain networks (PDRP/PDCP) of regional cerebral glucose metabolism (rCMR). PDRP activity measured with FDG/H215O PET images disclosed opposite network changes in rCMR and regional cerebral blood flow (rCBF) following levodopa infusion (1). Analogous PDRP/PDCP networks were generated recently with resting state fMRI (rsfMRI) (2). In this study we compared levodopa mediated network modulation in PD patients scanned with FDG PET, arterial spin label (ASL) perfusion MRI and rsfMRI.
Methods: Eight moderate stage PD patients (gender 7M/2F; age 60.6 ± 5.4 years) underwent FDG PET and 3T ASL MRI and rsfMRI before (12 hours off medication) and after an acute dose of levodopa. Network scores of PDRP and PDCP identified with FDG PET were computed for rCMR and rCBF images with those derived with rsfMRI computed for rsfMRI data only. These scores were compared on- and off-medication for each imaging modality.
Results: PDRP scores in the PD patients decreased in rCMR (p = 0.039) and rsfMRI (p = 0.017) data but increased in rCBF (p = 0.022) data following acute levodopa treatment. By contrast, no levodopa-mediated changes were seen in PDCP scores in the PD patients measured by all three types of imaging data.
Conclusions: The difference in PDRP modulation between rCMR and rCBF images confirms the resting-state dissociation of metabolic and neurovascular responses to levodopa in PD (1). This work supports more therapeutic studies to evaluate clinical-network correlations using biomarkers with simpler and non-invasive functional MRI.
References
1. Hirano, S. (2008). Dissociation of metabolic and neurovascular responses to levodopa in the treatment of Parkinson's disease. J Neurosci 28: 4201–9
2. Vo, A. (2016). Parkinson's disease-related network topographies characterized with resting state functional MRI. Hum Brain Mapp: epub, May 22, 2016 (DOI: 10.1002/hbm.23260)
PS02-108
Poster Viewing Session II
Brain networks of cerebral metabolism and perfusion associated with cerebellar variant of multiple system atrophy: a FDG PET and ASL MRI study
S. Peng1, J. Ge2, P. Wu2, J. Wang3, V. Dhawan1, D. Eidelberg1, C. Zuo2 and Y. Ma1
1The Feinstein Institute for Medical Research, Center for Neurosciences, Manhasset, United States
2Huashan Hospital of Fudan University, PET Center, Shanghai, China
3Huashan Hospital of Fudan University, Neurology, Shanghai, China
Abstract
Objectives: Multiple system atrophy (MSA) is associated with a specific metabolic brain network (MSARP) which can aid early differential diagnosis of parkinsonism (1). MSA includes both parkinsonian (MSA-P) and cerebellar (MSA-C) clinical variants. In this study we sought to identify brain networks of abnormal cerebral metabolism and perfusion in MSA-C.
Methods: 16 Chinese patients with MSA-C (age 57.3 ± 6.7y), 16 MSA-P (59.6 ± 8.2y), 16 PD (58.4 ± 4.5y), 16 PSP (62.9 ± 9.0y) and 16 healthy controls (58.7 ± 4.6y) underwent FDG PET and 3T arterial spin labeling (ASL) MRI. Images of MSA-C patients and controls were used to identify brain networks associated with abnormal metabolism and perfusion (3). Network expression was computed and compared across the groups.
Results: MSA-C metabolic pattern (MSACRP-FDG) was characterized by bilateral decreases in the cerebellum (Fig. 1). Compared to the controls its expression was elevated (p< 0.0001) in both MSA-C and MSA-P patients but decreased in both PD and PSP patients (p< 0.02). MSACRP scores were lower (p< 0.01) in MSA-P than in MSA-C patients. In addition, MSA-C perfusion pattern (MSACRP-ASL) was characterized bilaterally by decreases in the cerebellum and increases in the thalamus and precuneus (Fig. 2). Its expression was elevated in the MSA-C and MSA-P patients (p< 0.0001) compared with the controls and PD/PSP patients but lower in the MSA-P than in MSA-C patients (p< 0.01).
Conclusions: MSA- cerebellar patients presented similar brain networks of abnormal cerebral metabolism and perfusion. Both measures may provide viable markers to discriminate two clinical subtypes of MSA as well as other forms of parkinsonism.
References
1. Poston, KL (2012). Network correlates of disease severity in multiple system atrophy. Neurology 78: 1237–1244.
2. Peng, S (2014). Characterization of disease-related covariance topographies with SSMPCA toolbox: effects of spatial normalization and PET scanners. Hum Brain Mapp 35: 1801–14.
