Abstract
Basic Science
OC-BA-001
Characterization of trigeminal ganglion cell spontaneous calcium signalling and responses to ATP, PACAP and CGRP
Sajedeh Eftekhari1,* and Andrew Charles1
1Neurology, David Geffen School of Medicine at UCLA, Los Angeles, United States
Objectives
The trigeminal ganglion (TG) consists of bipolar neurons of different cell sizes and two types of glial cells; satellite glial cells and Schwann cells. The satellite glial cells surround neuronal cell bodies. The CGRP receptor is localized on the large-sized neurons and satellite glial cells in rat and human TG. The TG neurons also express PAC1 receptors. It is not known if and how PACAP and CGRP effect the calcium signaling in TG. We aimed to characterize the different cell types of TG based on their spontaneous calcium signaling activity and responses to ATP. We also examined the responses of satellite glia and neighbouring TG neurons to acute and chronic application of CGRP or PACAP.
Methods
Primary cultures of TG were prepared from mice p5-p7. Cultured cells were then loaded with the Ca2+-specific fluorescent indicator fluo-4AM, and Ca2+ responses were quantified using a custom confocal imaging system. Responses of different cell types in the TG culture to ATP, CGRP or PACAP were analyzed. Parameters quantified included baseline intracellular calcium, spontaneous calcium transients, and the amplitude and duration of response to applied ligands. To confirm our results, we used two different cell lines with spontaneous calcium oscillations; GT1-7 (mouse hypothalamic tumor neurons) and GH3 (rat pituitary tumor cells) expressing CGRP and PAC1 receptor.
Results
We have established a cell culture system in which TG neurons develop characteristic cell morphology with extensive processes. Satellite glial cells grow in close contact with the neuronal cell bodies, with morphology similar to that observed in vivo. Spontaneous neuronal calcium transients were observed in neurons and satellite glial cells, with differences in their temporal and spatial characteristics. Addition of ATP activated an increase in [Ca2+]I in both neurons and glia, with neurons showing a rapid and transient response and glia showing a slower and more sustained response. CGRP induced Ca2+ increase in some TG neurons, while PACAP induced Ca2+ increase in some cells, mostly in glia cells. However, this was observed in very few cells. CGRP and PACAP did not change intracellular calcium in either the GT1-7 cell line or the GH3 cell line.
Conclusion
This result suggests that the different cell types of TG may be defined based on their spontaneous activity and their intercellular Ca2+ response to ATP. Our results also indicate that CGRP and PACAP do not consistently change intracellular Ca2+ in TG cells.
Disclosure of Interest
None Declared
Basic Science
OC-BA-002
LOCUS COERULEUS NORADRANERGIC PROJECTIONS MODULATE CORTICAL SPREADING DEPRESSION THRESHOLDS IN RATS
Marta Vila-Pueyo1,*, Peter J. Goadsby1 and Philip R. Holland1
1Headache Group, King’s College London, London, United Kingdom
Objectives
The noradrenergic locus coeruleus (LC) is a key modulator of the sleep-wake cycle, acting as a promoter of arousal. Additionally, noradrenergic projections are involved in the regulation of cerebral blood flow and LC stimulation reduces cerebral blood flow. To explore further a potential role for the LC in migraine pathophysiology, we aimed to test whether LC disruption would modulate cortical spreading depression (CSD) thresholds.
Methods
Sprague-Dawley rats (n = 28) were randomly treated with vehicle (saline) or N-(2-chloroethyl)-N-ethyl-2-bromobenzylamine (DSP4), a selective neurotoxin that initially induces degeneration of LC noradrenergic axon terminals followed by their cell bodies. Two weeks after treatment, rats were anesthetized with isoflurane and maintained with propofol infusion (33–50 mg/kg/h). Two cranial windows were drilled in each parietal bone for electrical or chemical induction of CSDs and for DC cortical recordings. Following 30 minutes of baseline recordings in the left hemisphere, the left cortex was electrically stimulated with increasing electric charge until a CSD was induced. Afterwards, baseline recordings were performed for 30 minutes in the right hemisphere, then a cotton ball soaked in 1M KCl was placed on the right cortex and CSDs were counted for 1 hour, with KCl refreshed every 15 minutes (5 µl).
Results
DSP4 treatment resulted in selective loss of 49% (±6.5) of the noradrenergic cells in the LC (t26 = 5.083, p ≤ 0.01) and rats demonstrated a lethargic phenotype. This loss of LC noradrenergic cell bodies was associated with an increased propagation of KCl-induced CSDs (t23 = −3.164, p ≤ 0.001), more pronouncedly during the last 30 minutes of recordings (t23 = −3.215, p ≤ 0.01). In agreement with the increased propagation of KCl induced CSD’s the electrical threshold for CSD induction was significantly lower in LC ablated rats (U = 43, p = 0.028).
Conclusion
The LC sends dense noradrenergic projections to the entire cortex to induce wakefulness, loss of LC neurons resulted in the induction of a lethargic phenotype in rats and a significantly reduced threshold for CSD. As such, perturbation of the brainstem LC may play a critical role in migraine attack susceptibility and explain in part the increased prevalence of attacks during the early arousal phase.
This work was funded by MRC grant (MR/P006264/1) and Welcome Trust (Synaptopathies).
Disclosure of Interest
M. Vila-Pueyo: None Declared, P. Goadsby Conflict with: Grants and personal fees from Allergan, eNeura Inc., and Amgen Inc.; personal fees from Autonomic Technologies Inc., Alder Biopharmaceuticals, Pizer Inc., Dr. Reddy's Laboratories, Zosano Pharma Corporation, Colucid Pharmaceuticals, Ltd., Eli-Lilly and Company, Avanir Pharmaceuticals, WL Gore & Associates, Heptares Therapeutics, Nupathe Inc., Teva, Cipla Ltd., Ajinomoto Pharmaceuticals Co., Akita Biomedical, Wells Fargo, Ethicon, US, EMKinetics, Promius Pharma, Supernus, Trigemina, MedicoLegal work, Journal Watch, Up-to-Date. In addition, Dr. Goadsby has a patent Magnetic stimulation for headache pending., P. Holland Conflict with: Unrelated to this abstract, grants from Amgen and honoraria and travel expenses in relation to ed- ucational duties from Allergan and Almirall
Basic Science
OC-BA-003
Dissecting Migraine with Optogenetics: An aversive circuit from the periaqueductal gray to the ventral tegmental area
Maggie W. Waung1,* and Howard L. Fields1
1Neurology, University of California San Francisco, San Francisco, United States
Objectives
Imaging studies of patients have shown that migraine attacks correlate with evidence of increased activity in the periaqueductal gray (PAG). However, it is unclear how these changes contribute to headache. Using optogenetic circuit manipulation, we present data demonstrating a connection between the PAG to the ventral tegmental area (VTA) and evaluate its contribution to pain processing in a rodent model of headache.
Methods
In Sprague Dawley rats, adeno-associated virus containing a light-activated cation channel (AAV2-hSynapsin-ChR2-mcherry) is stereotaxically delivered to bilateral ventrolateral PAG. Four weeks later, acute horizontal VTA slices are prepared for intracellular recordings. Mcherry-positive fibers originating in the PAG can be visualized in horizontal VTA slices and light-evoked post-synaptic potentials (PSPs) can be elicited from them using whole cell patch clamp techniques to record from VTA neurons.
In behavioral experiments, animals receive PAG injections with ChR2 or sham virus. After 3–5 weeks of viral expression, optical fibers are implanted into the bilateral VTA. In a real-time place preference (PP) assay, animals are placed in a chamber separated into 2 areas with distinct contextual cues. When the animal enters the side designated for light stimulation, the laser is turned on (473 nm, 5 ms pulses at 20 Hz, 15 mW) and remains on until the animal exits the light-paired side. After three 20-minute sessions on one side, light is activated on the opposite side for an additional 3 sessions.
To determine whether this circuit alters behavior in an animal model of headache, the inhibitory chloride pump (AAV2-hSynapsin-eNpHR3.0-mcherry) is delivered into bilateral PAG. Three to five weeks later, rats undergo placement of optical VTA fibers and a dural cannula for inflammatory soup (IS) infusion, an established headache model in rodents. Real-time conditioned PP sessions with activation of halorhodopsin (525 nm, continuous, 10 mW) are performed in the presence and absence of inflammatory soup.
Results
Light stimulation (473 nm, 5 ms, 3 mW) of PAG axon terminal fibers in the VTA produces PSPs at a short fixed latency in a subset of VTA neurons, indicating these neurons receive direct synaptic input from the PAG. A majority of these connections are excitatory, as light-evoked responses are inhibited by the AMPA receptor antagonist, DNQX.
Activation of these PAG inputs to the VTA is also adequate to induce avoidance behavior. After two 20 minute sessions, rats with active ChR2 virus in the PAG demonstrate aversion to the light-paired chamber. Animals with sham virus exhibit a difference score (ds) of 180.8 ± 134.1 s, while animals with ChR2 have an average ds of −456.9 ± 91.2 s (p = 0.003, n = 6 per condition). Furthermore, this avoidance behavior reverses sides within one session when light stimulation is alternated between the 2 sides of the chamber.
In preliminary experiments, inactivation of PAG to VTA projections with halorhodopsin elicits a conditioned place preference in animals receiving dural IS, but not in animals receiving dural phosphate buffered saline (PBS) infusion. After 2 conditioning sessions, animals with dural IS spend more time on the side where they received light-activated inhibition (ds 360.5 ± 175.7 s, n = 5), while animals without headache (receiving dural PBS) do not demonstrate a preference (ds −108.5 ± 201.5 s, n = 2).
Conclusion
These studies demonstrate an excitatory glutamatergic connection from the PAG to the VTA. Activation of this circuit is aversive, and this connection appears to be active during headache, but not at baseline. This circuit may be sensitive to therapeutic targets for migraine and become upregulated or refractory to treatment in chronic headache.
Disclosure of Interest
None Declared
Basic Science
OC-BA-004
Nociceptive trigeminal neurotransmission is inhibited by a PAC-1 receptor antibody in an in vivo model relevant to migraine
Jan Hoffmann1,*, Margarida Martins-Oliveira1,2, Simon Akerman1, Weera Supronsinchai1, Cen Xu3 and Peter J. Goadsby1,2
1Headache Group - Department of Neurology, University of California San Francisco, San Francisco, United States
2Headache Group - Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, United Kingdom
3Department of Neuroscience, Amgen Inc., Thousand Oaks, CA, United States
Objectives
Pituitary adenylate cyclase-activating polypeptide 38 (PACAP-38) is released into the cranial circulation during an acute migraine attack and returns to its normal concentration after successful abortive treatment with sumatriptan. When infused systemically PACAP-38 induces migraine-like attacks in migraineurs. In line with these observations preclinical data from in vivo studies show that PACAP-38 increases spontaneous as well as stimulus-induced neuronal activity within the trigeminal complex (TCC) and suggest that this effect may be mediated by PAC-1 receptors.
The aim of the study was to investigate the efficacy of a PAC-1 receptor antibody on nociceptive neuronal transmission in the trigeminocervical complex in an in vivo model of migraine.
Methods
Male Sprague-Dawley rats were anesthetized using a single dose of pentobarbital (60 mgkg−1) for induction and propofol (20–25 mgkg−1h−1) for maintenance throughout the experiment. For electrical stimulation a cranial window was opened in the parietal bone and a bipolar stimulating electrode was placed on the intact dura mater above the middle meningeal artery. For extracellular recordings of nociceptive neuronal activity a C1 laminectomy was performed and a tungsten electrode was placed within the TCC. During the experiment primary trigeminal afferents were stimulated supramaximally with square wave pulses.
A PAC-1 receptor antibody (10 mgkg−1) or its vehicle were administered intravenously followed by a resting period of 2.5 hours. Sumatriptan (10 mgkg−1) or its vehicle were then administered intravenously followed by a resting period of 30 minutes. Post-stimulus histograms and background activity were then recorded in the TCC over 45 minutes.
Results
The systemic administration of the PAC-1 receptor antibody induced an inhibition of stimulus-evoked nociceptive activity in the TCC (−40 ± 11%, F1.54, 6.17 = 9.30, p = 0.016) when compared to its baseline. Likewise, sumatriptan, which served as a positive control, significantly inhibited stimulus-evoked neuronal activity (−30 ± 11%, F2.10, 14.67 = 5.11, p = 0.020), whereas vehicle control did not show a significant effect (−18 ± 9%, F1.98, 13.83 = 2.31, p = 0.136). In none of the groups a significant effect on spontaneous background activity was observed.
The PAC-1 receptor antibody had no effect on arterial blood pressure whereas sumatriptan induced a minor decrease (−12.9 ± 3%, F2.41, 16.89 = 5.75, p = 0.009).
Conclusion
The PAC-1 receptor antibody effectively inhibits stimulus-evoked neuronal activity in the TCC. Taken together with experimental medicine studies the new results support targeting the PAC-1 receptor with an antibody as a novel and promising mechanism for the preventive treatment of migraine.
Disclosure of Interest
J. Hoffmann Conflict with: Dr. Hoffmann received honoraria for consulting from Allergan, Autonomic Technologies Inc. (ATI) and Novartis, Conflict with: Dr. Hoffmann received honoraria for speaking from Allergan and Teva, M. Martins-Oliveira: None Declared, S. Akerman Conflict with: Dr. Akerman received an unrestricted grant from electroCore LLC, Conflict with: Dr. Akerman received travel reimbursements from electroCore LLC, W. Supronsinchai: None Declared, C. Xu Conflict with: Dr. Xu is an employee of Amgen Inc., P. Goadsby Conflict with: Dr. Goadsby reports grants from Allergan, Amgen and Eli Lilly and Company, Conflict with: Dr. Goadsby reports personal fees from Akita Biomedical, Alder Biopharmaceuticals, Allergan, Amgen, Autonomic Technologies Inc., Avanir Pharma, Cipla Ltd., Colucid Pharmaceuticals Ltd, Dr Reddy's Laboratories, Eli Lilly and Company, eNeura, Electrocore LLC, Novartis, Pfizer Inc, Promius Pharma, Quest Diagnostics, Scion, Teva Pharmaceuticals, Trigemina Inc.; and personal fees from MedicoLegal work, Journal Watch, Up-to-Date, Oxford University Press; and in addition Dr. Goadsby has a patent Magnetic stimulation for headache pending assigned to eNeura.
Epidemiology
OC-EP-001
Medical Comorbidities of Migraine: Results from the Chronic Migraine Epidemiology and Outcomes (CaMEO) Study
Richard B. Lipton1,*, Vincent T. Martin2, Michael L. Reed3, Kristina M. Fanning3, Aubrey Manack Adams4, Dawn C. Buse5 and Peter J. Goadsby6
1Montefiore Headache Center, Department of Neurology, Albert Einstein College of Medicine, Bronx
2University of Cincinnati Headache and Facial Pain Center, University of Cincinnati College of Medicine, Cincinnati
3Vedanta Research, Chapel Hill
4Allergan plc, Irvine
5Montefiore Headache Center, Bronx
66UCSF Department of Neurology, San Francisco, United States
Objectives
Many of the comorbidities associated with migraine have a higher relative frequency in chronic migraine (CM) than in episodic migraine (EM). The objective of this study was to replicate and extend prior work on comorbid medical conditions in a systematically recruited sample of people with EM and CM.
Methods
Data are from the Chronic Migraine Epidemiology and Outcomes (CaMEO) Study, a
prospective, web-based study with cross-sectional modules embedded in a longitudinal
design. Participants were recruited from an online panel using quota sampling. Data
from the baseline diagnostic survey were used to identify people with EM and CM
based on criteria modified from the International Classification of Headache
Disorders, third edition, beta version (ICHD-3 beta). Participants completed a
Comorbidities/Endophenotypes module that assessed 64 symptoms (e.g., dizziness) and
conditions (e.g., asthma). Respondents were asked (1) if they ever had a specific
symptom (“Self-Reported [SR]”) or condition and, if present, (2) if the SR symptom
or condition had been confirmed/diagnosed by a “doctor” (“SR-physician diagnosis
[SR-PD]”). SR data were used to define the presence of symptoms such as
dizziness/vertigo (
Image: 
Results
Available CaMEO respondents with migraine (16,763) were sent the
Comorbidities/Endophenotype module and 12,810 (76.4%) provided valid responses:
11,669 with EM; 1,111 with CM. Compared with the EM group, the CM group had a
similar mean age (EM, 41.3 years; CM, 41.9 years), was more likely to be female (EM,
74.2%; CM, 81.5%; P < 0.001) and white (EM, 84.0%; CM, 88.7%;
P < 0.001), and had a mean higher body mass index (EM,
27.7 kg/m2; CM, 28.7 kg/m2;
P < 0.001). The relative frequencies were significantly higher
for 29 (93.5%) of the 31 SR symptoms and SR-PD conditions assessed. Conditions or
groups of conditions with relative frequencies >10% higher in CM than EM included
allergies/hay fever/allergic rhinitis (EM, 37.4%; CM, 51.0%), sinusitis/sinus
infection (EM, 47.3%; CM, 58.8%), insomnia (EM, 35.6%; CM, 50.2%),
vertigo/dizziness/balance problems (EM, 17.8%; CM, 29.7%), and gastroesophageal
reflux disease (EM, 14.3%; CM, 24.4%;
Conclusion
Overall, significantly more respondents with CM vs. EM reported medical symptoms or conditions. Multiple mechanisms might explain this association including manifestations of migraine, direct causality (e.g., CM directly causes the comorbidity), reverse causality (e.g., the condition increases the risk of CM), and shared genetic or environmental risk factors. Confounding or detection bias (i.e., “Berkson’s Bias”) could contribute to the findings. Future analyses will address naturally occurring subgroups (taxa) defined by migraine phenotypes and comorbidities and assess the relationships of these groups to external validators such as treatment response and clinical course.
Disclosure of Interest
R. Lipton Conflict with: eNeura Therapeutics and Biohaven, Conflict with: NIH, Conflict with: Alder, Allergan, Amgen, Autonomic Technologies, Avanir, Biohaven, Inc, Boston Scientific, Colucid, Dr. Reddy’s Laboratories, Electrocore, Eli Lilly, eNeura Therapeutics, Glaxo, Merck, GlaxoSmithKlein, Pfizer, Teva, and Vedanta, Conflict with: Served on the editorial board of Neurology and as senior advisor to Headache. Received support from the Migraine Research Foundation and the National Headache Foundation. He has reviewed for the NIA and NINDS. Receives royalties from Wolff’s Headache, 8th Edition, Oxford Press University, 2009 and Informa, V. Martin Conflict with: Amgen, Alder, Avenir, and Eli Lilly, Conflict with: Teva, Allergan, and Depomed, M. Reed Conflict with: Managing Director of Vedanta Research, which has received research funding from Allergan, Amgen, CoLucid, Dr. Reddy’s Laboratories, Endo Pharmaceuticals, GlaxoSmithKline, Merck & Co., Inc., NuPathe, Novartis, and Ortho-McNeil, via grants to the National Headache Foundation. Vedanta Research has received funding directly from Allergan for work on the CaMEO Study, K. Fanning Conflict with: Vedanta Research, which has received research funding from Allergan, Amgen, CoLucid, Dr. Reddy’s Laboratories, Endo Pharmaceuticals, GlaxoSmithKline, Merck & Co., Inc., NuPathe, Novartis, and Ortho-McNeil, via grants to the National Headache Foundation, A. Manack Adams Conflict with: Allergan, Conflict with: Allergan, D. Buse Conflict with: Allergan, Amgen, and Dr. Reddy’s Laboratories, Conflict with: Eli Lilly, Conflict with: Montefiore Medical Center, which in the past 12 months, has received research support funded by Allergan, Alder, Avanir, CoLucid, Dr. Reddy’s Laboratories, and Labrys via grants to the National Headache Foundation and/or Montefiore Medical Center, Conflict with: Editorial board of Current Pain and Headache Reports, the Journal of Headacheand and Pain, Pain Medicine News, and Pain Pathways magazine, P. Goadsby Conflict with: Allergan, Amgen, Eli Lilly and Company, and eNeura Inc Consultant: Allergan, Akita Biomedical, Alder Biopharmaceuticals, Amgen, Autonomic Technologies Inc, Avanir Pharma, Cipla Ltd, CoLucid Pharmaceuticals Ltd, ElectroCore LLC, Eli-Lilly and Company, eNeura Inc, Novartis, Pfizer Inc, Promius Pharma, Quest Diagnostics, DrReddy’s Laboratories, Scion, Teva Pharmaceuticals and Trigemina Inc., Conflict with: Patent pending to eNeura: Magnetic stimulation for headache, Conflict with: Personal fees from MedicoLegal work in headache, Journal Watch, Up-to-Date, and Oxford University Press
Epidemiology
OC-EP-002
Use and overuse of triptans in Austria – a survey based on nationwide sickness claims data
Karin Zebenholzer1,*, Walter Gall2 and Christian Woeber1
1Department of Neurology
2Center for Medical Statistics, Informatics and Intelligent Systems, Medical University of Vienna, Vienna, Austria
Objectives
The aim of our study was to evaluate the prescription of triptans in Austria. With only minor exceptions, every inhabitant has to be insured by one of the social security institutions. A nationwide research database (GAP-DRG) of the Hauptverband der Österreichischen Sozialversicherungsträger provides anonymous data on dispensed drugs, sex, age and other details for particular years.
Methods
For 2007 data on 7 426 412 insured persons were available. We included persons aged 18–99 years with known sex and with billable insurance benefits in 2007, this excludes benefits to persons released of prescription charges. Thus the research population comprised 5918487 persons. We analysed billed prescriptions, i.e. dispensed tablets. We defined triptan use as dispensation of at least one package of a triptan in 2007, we defined triptan overuse as 30 or more tablets dispensed per quarter in at least one quarter of 2007 and used Mann-Whitney-U tests and Chi2 tests for comparisons between all persons, triptan non- users and triptan users, separating the latter in non-overusers and overusers.
Results
Among all included persons 54 % were female, 46 % male, median age was 47 years, 33062 persons (0,56 %) received a at least one triptan prescription in 2007, 1970 persons were triptan overusers (5.9 % of triptan users, 0.033% of the research population), thereof 45 % overused triptans in one quarter, 21% in two quarters, 16% in three quarters and 18 % in four quarters of 2007. Triptan users were significantly younger than non-users (44 vs. 47 years, p < 0.001), and comprised significantly more women (82 % vs. 54 %, p < 0.001). The median number of dispensed triptans per year was 12 in non-overusers and 102 in overusers. (p < 0.001). Compared to non-users triptan users had significantly more median days of sick-leave in general (12 vs. 10, p < 0.001) and sick-leave due to migraine (3 vs. 2 days, p < 0.001). Significantly more triptan users and overusers were living in predominantly urban areas compared to all insured persons.
Conclusion
In the general population of Austria a triptan prescription rate of 0,56 % contrasts with a migraine prevalence of 10 %. Thus, the estimated proportion of persons with migraine using a triptan is less than 6 %. Triptan overuse is uncommon in the general population, but affects 1 of 17 triptan users. The finding that both use and overuse of triptans is more common in urban areas may be explained by socioeconomic conditions or by the availability of physicians. Our study suggests that migraine attacks are severely undertreated in Austria and that triptan overuse is not uncommon among triptan users. Management of migraine requires further improvement by promoting the use of triptans in patients who do not achieve freedom from migraine within 2 hours with two or more adequately dosed analgesics or NSAIDs taken early during the attack and by educating about the consequences of triptan overuse.
Disclosure of Interest
None Declared
Epidemiology
OC-EP-003
Association of 30 year Cardiovascular Disease Risk with Migraine Diagnosis and Childhood Abuse in Young Adults - Findings from the Add Health study
Monita Karmakar1,2, Aliaksandr A. Amialchuk3 and Gretchen E. Tietjen1,*
1Department of Neurology
2School of Population Health
3Department of Economics, University of Toledo, Toledo, United States
Objectives
Both migraine and childhood abuse have been found to be associated with cardiovascular disease (CVD) risk. Further, migraine has been linked with childhood abuse, especially emotional abuse. The 30 year Framingham CVD risk scoring is an evidence based method for calculating cardiovascular risk for young adults, 20–30 year old. Previous studies looking at the association of migraine and Framingham risk score focused on an older population using the 10 year CVD risk. The current study investigates the independent effects of migraine and childhood abuse on 30 year Framingham (CVD) risk score in young adults. We also assess the interaction effect of migraine and childhood abuse on the 30 year Framingham (CVD) risk.
Methods
We analyzed retrospective, cross-sectional data from 12,606 adults aged 24–32 years in Wave 4 of the Add Health study (2008). Participants were queried regarding maltreatment (emotional, physical and sexual) during childhood, diagnosis of migraine and other health conditions by a health care provider, health behaviors, and socio-demographics. Height, weight, blood pressure, glycated hemoglobin (HbA1c), and list of medications were also documented during in-home visits. 30 year risk score for cardiovascular diseases was calculated for each participants using Framingham based prediction model using their age, sex, body mass index, smoking status, systolic blood pressure, diabetes and use of antihypertensive medications. Linear regressions were used to assess the main independent effect and the interaction effect on the log transformed 30 year Framingham (CVD) risk Score.
Image:
Results
About 14% of the total sample reported a migraine diagnosis. The 30 year Framingham (CVD) risk score was positively and independently associated with migraine diagnosis (β = 0.084, SE = ±0.02, p < 0.05) and self-reported frequency of childhood emotional abuse (β = 0.010, SE = ±0.001, p < 0.05), after controlling for age, sex, race, ethnicity and income. Subsequent subgroup analysis showed that the associations differed by the sex. In females, both migraine diagnosis (β = 0.095, SE = ±0.03, p < 0.05) and self-reported frequency of childhood emotional abuse (β = 0.018, SE = ±0.01, p < 0.05) had a significant effect on Framingham (CVD) risk score which was independent of each other. However, in males, only migraine diagnosis (β = 0.080, SE = ±0.04, p < 0.05) showed a significant main effect on the Framingham (CVD) risk score. There was no significant interaction between migraine diagnosis and the self-reported frequency of any type of childhood abuse (p > 0.05) in the entire sample nor in the subgroup analysis.
Conclusion
Both childhood abuse and migraine significantly increase the risk of cardiovascular disease, independently of each other. However, there is no interaction of these two variables on CVD risk, meaning the effects of both are additive but not synergistic. These findings need to be corroborated by future studies.
Disclosure of Interest
M. Karmakar: None Declared, A. Amialchuk: None Declared, G. Tietjen Conflict with: owns common stock in Johnson & Johnson, and Stryker, Conflict with: serves on advisory boards of Eli Lilly, and Dr. Reddy’s
Epidemiology
OC-EP-004
Validation of a Questionnaire to Assess Photophobia
Melissa Cortez1,*, Durin Uddin2, Andi Blitzer2, Man Hung3, Jerry Bounsanga3, Yushan Gu3, Maren Voss3, Kathleen Digre4 and Bradley Katz4
1Department of Neurology
2Department of Ophthalmology and Visual Sciences
3Department of Orthopaedics
4Departments of Ophthalmology and Neurology, University of Utah, Salt Lake City, United States
Objectives
A number of neurologic and ophthalmic conditions are associated with abnormal light sensitivity (photophobia), but the most prevalent condition is migraine. We previously developed a questionnaire to quantify patients’ light sensitivity symptoms and the effects of their light sensitivity on activities of daily living. The objective of the current investigation was to validate this photophobia questionnaire by 1) comparing the psychometric properties of the photophobia questionnaire against a recently validated Korean questionnaire, and 2) to determine the relationship between patients’ photophobia questionnaire scores and their level of light sensitivity.
Methods
We randomly recruited subjects from the neurology and ophthalmology clinics. After informed consent, subjects completed our 16-item photophobia questionnaire and the Korean 8-item questionnaire. Subjects were then seated in front of a calibrated light source. Following a period of dark adaptation, the examiner gradually increased the luminance of the source until the participant said, “stop”, at which point their experience of the light became painful (designated as their light sensitivity threshold). This process was repeated three times and the average log lux of the stop points was recorded.
We used descriptive statistics to examine patient demographic characteristics and applied Pearson correlations to assess the associations between measures. An alpha of 0.05 (two-sided) was considered significant. Rasch analyses were conducted on the Korean and Photophobia questionnaires using the Rasch rating scale and the partial credit models respectively, from cross-sectional data.
Results
We included subjects both with and without light sensitive conditions. The study sample consisted of 95 patients: 72 females (75.8%), 83 Caucasians (87.4%), mean age of 47 years (range 18 to 79). There was a significant correlation between our 16-item photophobia questionnaire and the Korean questionnaire r = 0.787 (p < 0.05). Our photophobia questionnaire was found to have relatively good instrument targeting that was much better than the Korean questionnaire. Light sensitivity thresholds were significantly correlated between both the Korean 8-item questionnaire −0.535 (p < 0.05) and our 16-item photophobia questionnaire −0.411 (p < 0.05).
Conclusion
By including subjects with a wide range of photophobia (from no photophobia to severe photophobia) we were able to rigorously evaluate our photophobia questionnaire. Scores on our 16-item photophobia questionnaire correlated well with light sensitivity thresholds and with the previously validated Korean questionnaire. This study indicated that our photophobia questionnaire may have some advantages over the Korean questionnaire. Our questionnaire may be a reasonable surrogate measure in future studies designed to better understand the causes of and treatments for photophobia.
Disclosure of Interest
M. Cortez: None Declared, D. Uddin: None Declared, A. Blitzer: None Declared, M. Hung: None Declared, J. Bounsanga: None Declared, Y. Gu: None Declared, M. Voss: None Declared, K. Digre Conflict with: patent, B. Katz Conflict with: CEO of Axon Optics, Conflict with: Patent
Imaging and Human Studies
OC-IH-001
Reproducibility of migraine-like attacks induced by phosphodiesterase-3-inhibitor cilostazol
Sabrina Khan1,*, Marie Deen1, Anders Hougaard1, Faisal Mohammad Amin1 and Messoud Ashina1
1Danish Headache Center & Dept. of Neurology, Copenhagen, Denmark
Objectives
The phosphodiesterase-3-inhibitor cilostazol induces migraine-like attacks in patients with migraine without aura and may be used as a pharmacological trigger in human experimental models of migraine. However, the reproducibility of cilostazol-induced migraine-like attacks has never been investigated.
Methods
We performed a post-hoc analysis of clinical data from two brain-imaging studies including subjects who had received cilostazol 200 mg orally. Only subjects who developed migraine-like attacks on study day 1 were included on study day 2. After cilostazol ingestion, subjects and the investigator recorded headache intensity and characteristics once every hour on a purpose-developed questionnaire. Primary end-points included incidence and time to onset of migraine-like attacks between two separate study days.
Results
Thirty-four subjects completed both experimental days and were included in this study. Thirty-four out of 34 subjects (100%) developed migraine-like attacks after cilostazol ingestion on both study days 1 and 2. Time to onset of migraine was 5 hours (range 1–8 hours) on study day 1 and 4 hours (range 1–8 hours) on study day 2, p = 0.16. We found no difference in median peak headache score, median time to peak headache score, or median time to intake of rescue medication between study days 1 and 2.
Conclusion
A second-time administration of cilostazol reproduces migraine-like attacks in all subjects who report an attack after their first cilostazol induction. There was no difference in time to migraine onset between separate inductions. Experimental migraine-provocation using cilostazol is a highly efficient and useful approach for studying the ictal phase of migraine without aura.
Disclosure of Interest
S. Khan Conflict with: S. Khan has acted as invited speaker for Novartis during the conduct of this study., M. Deen: None Declared, A. Hougaard: None Declared, F. Mohammad Amin: None Declared, M. Ashina Conflict with: M. Ashina reports grants from Lundbeck Foundation (R155-2014-171) and Novo Nordisk Foundation (NNF11OC101433) during the conduct of the study., Conflict with: M. Ashina is a consultant or scientific advisor for Allergan, Amgen, Alder, ATI, Eli Lilly, Novartis and Teva, primary investigator for Amgen 20120178 (Phase 2), 20120295 (Phase 2), 20130255 (OLE), 20120297 (Phase 3) and GM-11 gamma-Core-R trials
Imaging and Human Studies
OC-IH-002
ALTERATIONS IN CEREBRAL BLOOD FLOW DURING THE POSTDROME PHASE OF A MIGRAINE ATTACK CAPTURED WITH ARTERIAL SPIN LABELLED (ASL) MRI
Pyari Bose1,2,*, Nazia Karsan1,2, Owen O'Daly3, Fernando Zelaya3 and Peter J. Goadsby1,4
1Headache Group, King's College London
2NIHR-Wellcome Trust King’s Clinical Research Facility, King's College Hospital
3Department of Neuroimaging Sciences, King's College London
4NIHR-Wellcome Trust King’s Clinical Research Facility, King’s College Hospital, London, United Kingdom
Objectives
Migraine has four main phases: premonitory, aura, headache and postdrome. Symptoms patients experience in the premonitory and postdromal phase of migraine are broadly similar. The postdrome of a migraine attack, however, is poorly characterised. Functional imaging methods have not been used to evaluate the postdrome phase in depth. Given that there are some similar symptoms experienced by subjects in the premonitory phase and postdrome phase, we wanted to study the premonitory and postdrome phase using a nitroglycerin induced human migraine model combined with arterial spin labelled (ASL) MRI to see if the activations involve similar brain regions. Pulsed continuous arterial spin labelled (pCASL) MRI is a non-invasive MRI technique to measure tissue perfusion that does not use ionizing radiation.
Methods
Sixteen subjects completed three study visits. ASL MRI scans over the course of triggered migraine attacks were analysed (SPM 12, www.fil.ion.ac.uk/spm). Voxel based analysis of premonitory scans of all subjects compared to postdrome scans of all subjects was carried out. Region of interest analysis (ROI) of key brain areas selected from previous functional imaging studies, such as the hypothalamus, pons, midbrain, thalamus, and anterior cingulate cortex was also carried out.
Results
With voxel based analysis, significant reductions were detected in rCBF (regional cerebral blood flow) over the superior frontal gyrus, medial frontal gyrus, middle frontal gyrus, putamen, superior temporal gyrus, middle temporal gyrus, inferior temporal gyrus, thalamus, hypothalamus, midbrain, posterior cingulate, anterior cingulate, claustrum (P < 0.001) in the postdrome phase compared to premonitory phase at a whole brain analysis level. Small volume correction showed additional areas of reduction in rCBF over the frontal medial orbital gyrus, insula, caudate, with peak reduction in rCBF over the left medial globus pallidus (P = 0.027, sphere set at 12mm radius of Voxel of interest) along with areas with reductions seen in rCBF at a whole brain level analysis.
With region of interest (ROI) analysis, we found statistically significant reductions in rCBF over the anterior cingulate cortex (ACC) in the postdrome phase compared to the premonitory phase (P = 0.002). The mean rCBF in the ACC during the premonitory phase was 58 ml/min/100ml tissue (mean ± SE; ±9) and mean rCBF in the ACC during the postdrome phase was 53 ml/min/100ml tissue (±7). Statistically significant reduction in rCBF were also seen in the insula in in the postdrome phase compared to the premonitory phase (P = 0.002). The mean rCBF in the Insula during the premonitory phase was 59 ml/min/100ml tissue (±10) and mean rCBF in the Insula during the postdrome phase was 54 ml/min/100ml tissue (±7).
Conclusion
The brain processes involved in the premonitory phase and postdrome phase are different. The symptoms experienced by subjects in the postdrome are associated with a near global reduction in cerebral blood flow. A computer based analogy of the postdrome would be the phase of migraine where the brain ‘re-boots’ itself before returning to normal function.
Disclosure of Interest
None Declared
Imaging and Human Studies
OC-IH-003
The similarities between spontaneous and nitroglycerin-triggered premonitory symptoms in migraineurs
Nazia Karsan1,2,*, Pyari Bose1,2, Charlotte Thompson1 and Peter J. Goadsby1,2
1Headache Group, Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, King's College London
2NIHR-Wellcome Trust King's Clinical Research Facility, King's College Hospital, London, United Kingdom
Objectives
Human models of migraine are required to understand the neurobiology of this disabling condition. Nitroglycerin (NTG) effectively triggers migraine headache in 60–80% of migraineurs, and has also been shown to trigger premonitory symptomatology.
We aimed to study the triggering of premonitory symptomatology with NTG, comparing the phenotype of triggered attacks to spontaneous attacks.
Methods
Migraineurs who reported spontaneous premonitory symptoms were recruited following informed consent (n = 49). A detailed migraine history was taken from each subject at screening, eligibility was rechecked, an electrocardiogram and physical examination were conducted and observations were documented.
NTG (0.5mcg/kg/min over 20 minutes) was administered intravenously to each subject. The phenotype of premonitory symptoms where present (n = 47) following triggering was recorded for each subject. A standardised physician-administered symptom questionnaire was used for both spontaneous and triggered attacks. Statistical analyses were performed to assess the correlation between common spontaneous and triggered symptoms using the Chi-squared test. P < 0.05 was considered significant.
Analyses were performed for fatigue, concentration difficulty, irritability, neck stiffness and yawning, as these were the most commonly displayed symptoms.
Cross tabulation of numbers of subjects with self-reported spontaneous and triggered common premonitory symptoms. P < 0.05 was considered significant (*).
Results
Triggered premonitory symptomatology was similar to spontaneous symptomatology, with a statistically significantly increased likelihood of reporting most of the common symptoms following triggering if reported in spontaneous attacks. Significant associations between spontaneous and triggered symptoms were found for fatigue (p = 0.002), neck stiffness (p = 0.004), irritability (p = 0.004) and yawning (p = 0.030). There was a trend towards significance for concentration difficulty (p = 0.053).
Conclusion
The similarities between spontaneous and triggered attacks suggest that NTG triggering is an effective model to study premonitory symptoms in migraine.
Disclosure of Interest
N. Karsan Conflict with: Dr Karsan is an Association of British Neurologists/Guarantors of Brain Clinical Research Training Fellow, P. Bose: None Declared, C. Thompson: None Declared, P. Goadsby Conflict with: Dr. Goadsby reports grants and personal fees from Allergan, Amgen, and Eli-Lilly and Company; and personal fees from Akita Biomedical, Alder Biopharmaceuticals, Autonomic Technologies Inc, Avanir Pharma, Cipla Ltd, Colucid Pharmaceuticals, Ltd, Dr Reddy's Laboratories, eNeura, Electrocore LLC, Novartis, Pfizer Inc, Promius Pharma, Quest Diagnostics, Scion, Teva Pharmaceuticals, Trigemina Inc., Scion, Conflict with: personal fees from MedicoLegal work, Journal Watch, Up-to-Date, Oxford University Press; and in addition, Dr. Goadsby has a patent Magnetic stimulation for headache pending assigned to eNeura
Imaging and Human Studies
OC-IH-004
Hemiplegic migraine: the elusive fourth gene and clinical differences between monogenic and complex polygenic forms
Nadine Pelzer1,*, Joost Haan1,2, Anine H. Stam1, Lisanne S. Vijfhuizen3, Stephany C. Koelewijn3, Amber Smagge1, Boukje de Vries3, Michel D. Ferrari1, Arn M. van den Maagdenberg1,3 and Gisela M. Terwindt1
1Neurology, Leiden University Medical Center, Leiden
2Neurology, Alrijne Hospital, Leiderdorp
3Human Genetics, Leiden University Medical Center, Leiden, Netherlands
Objectives
Hemiplegic migraine is a rare clinically and genetically heterogeneous subtype of migraine with aura which in a proportion of patients is caused by autosomal dominant mutations in CACNA1A, ATP1A2 or SCN1A. It is unknown whether the clinical characteristics of patients with and without such mutations differ, and whether the disease may also be caused by mutations in other genes.
Methods
We compared the clinical characteristics of 208 patients with familial (n = 199) or sporadic (n = 9) hemiplegic migraine due to a pathogenic mutation in CACNA1A, ATP1A2 or SCN1A with the clinical characteristics of 73 patients with familial (n = 49) or sporadic (n = 24) hemiplegic migraine without mutations in these genes. In addition, 47 patients (familial: n = 33; sporadic: n = 14) without mutations in CACNA1A, ATP1A2 or SCN1A were screened for mutations in novel genes using whole exome sequencing.
Results
Patients with mutations in CACNA1A, ATP1A2 or SCN1A had lower age at disease-onset, larger numbers of affected family members, and more often attacks which were: (i) triggered by mild head trauma; (ii) characterised by extensive severe motor weakness; and (iii) associated with brainstem features, confusion and brain oedema. Mental retardation and progressive ataxia were exclusively found in patients with a mutation. Whole exome sequencing failed to identify pathogenic mutations in new genes.
Conclusion
Most patients with hemiplegic migraine without a mutation in CACNA1A, ATP1A2 or SCN1A display a remarkably mild phenotype which seems more akin to that of common (non-hemiplegic) migraine and which most likely is caused by complex polygenic rather than by simple monogenic mechanisms. A fourth autosomal dominant gene for hemiplegic migraine remains elusive. These observations might guide physicians in selecting patients for mutation screening and in providing adequate genetic counselling.
Disclosure of Interest
None Declared
Imaging
OC-IM-001
Increased intrinsic brain connectivity between pons and somatosensory cortex during attacks of migraine with aura
Anders Hougaard1,*, Faisal M. Amin1, Henrik B. Larsson2, Egill Rostrup2 and Messoud Ashina1
1Danish Headache Center and Department of Neurology
2Functional Imaging Unit, Department of Clinical Physiology, Nuclear Medicine and PET, Rigshospitalet Glostrup, Faculty of Health and Medical Sciences, University of Copenhagen, Glostrup, Denmark
Objectives
The neurological disturbances of migraine aura are caused by transient cortical dysfunction due to waves of spreading depolarization that disrupt neuronal signaling. The effects of these cortical events on intrinsic brain connectivity during attacks of migraine aura have not previously been investigated. Studies of spontaneous migraine attacks are notoriously challenging due to their unpredictable nature and patient discomfort.
Methods
We investigated sixteen migraine patients with visual aura during attacks and in the attack-free state using resting state fMRI. We applied a hypothesis-driven seed-based approach focusing on cortical visual areas and areas involved in migraine pain, and a data-driven independent component analysis approach to detect changes in intrinsic brain signaling during attacks. In addition, we performed the analyses after mirroring the MRI data according to the side of perceived aura symptoms.
Image:
Results
We found a marked increase in connectivity during attacks between the left pons and the left primary somatosensory cortex including the head and face somatotopic areas (peak voxel: P = 0.0096, (x,y,z) = (−54, −32, 32), corresponding well with the majority of patients reporting right-sided pain. For aura-side normalized data, we found increased connectivity during attacks between visual area V5 and the lower middle frontal gyrus in the symptomatic hemisphere (peak voxel: P = 0.0194, (x,y,z) =(40,40,12).
Conclusion
The present study provides evidence of altered intrinsic brain connectivity during attacks of migraine with aura, which may reflect consequences of cortical spreading depression, suggesting a link between aura and headache mechanisms.
Disclosure of Interest
A. Hougaard: None Declared, F. Amin: None Declared, H. Larsson: None Declared, E. Rostrup: None Declared, M. Ashina Conflict with: Allergan, Amgen, Alder, ATI and Eli Lilly
Imaging
OC-IM-002
Resting-state functional connectivity in the visual network: a possible predictor for treatment response in chronic migraine
Dennis A Kies1,2,*, Judith A Pijpers2, Michel D Ferrari2, Mark C Kruit1 and Gisela M Terwindt2
1Radiology
2Neurology, Leiden University Medical Center, Leiden, Netherlands
Objectives
Up to 25% of migraineurs progress to chronic migraine (headache on ≥15 days per month, of which ≥8 migraine days). Although predisposing factors, such as depression and acute headache medication overuse, have been established, the exact mechanisms leading to migraine chronification and reversion are still uncertain. We investigated whether Resting-State functional connectivity (RS-fc) findings in chronic migraine patients predict good outcome after treatment.
Methods
Resting-state functional MR imaging was conducted in 112 participants with chronic migraine and medication overuse before and after treatment. Responders to treatment (≥50% reduction in headache days) were compared with non-responders (<50% reduction in headache days), using RS-fc within ten well-known functionally correlated networks. Data were preprocessed using a standard FSL pipeline (FSL v5.0.8) with addition of the AROMA motion correction tool, followed by analysis using a General Linear Model and permutation testing with 5000 permutations. Results were corrected for multiple comparisons within subject and between groups.
Results
Data of 99 participants was complete and useable for analysis (artifacts n = 7, incidental findings n = 2, lost to follow-up n = 4). Mean number of headache days at baseline was 21.2 per month. RS-fc analysis of the lateral visual network showed a large cluster of voxels in the right lateral occipital cortex stretching to the left lateral occipital cortex. This area showed a higher connectivity in responders versus non-responders at baseline (p = .015), and this higher functional connectivity decreased within responders from baseline to follow-up (p < .001).
Conclusion
Chronic migraineurs who responded to treatment, and reversed to episodic, showed a significantly higher RS-fc within the lateral visual network as compared to non-responders at baseline, as well as a significant decrease of RS-fc in this area after treatment.
Disclosure of Interest
None Declared
Imaging
OC-IM-003
Reduced grey matter density in chronic migraine patients: correlations with clinical features
Gianluca Coppola1,*, Barbara Petolicchio2, Antonio Di Renzo1, Emanuele Tinelli2, Vincenzo Parisi1, Gaia Cartocci2, Stefano Tardioli2, Francesca Caramia2, Vittorio Di Piero2 and Francesco Pierelli3
1Research Unit of Neurophysiology of Vision and Neurophthalmology, G. B. Bietti Foundation IRCCS
2Department of Neurology and Psychiatry, Sapienza University of Rome, Rome
3Headache Center, IRCCS-Neuromed, Pozzilli, Italy
Objectives
Few MRI studies have been performed so far in patients affected by chronic migraine (CM) and especially in those without medication overuse. Here, we performed voxel-based morphometry (VBM) analysis to investigate the grey matter (GM) density of the whole brain in patients affected by CM. Our aim was to investigate whether there are fluctuations in the GM densities in relation to CM clinical features.
Methods
Twenty untreated CM patients without a past medical history of medication overuse underwent 3T MRI scans and were compared to a group of 20 healthy volunteers (HV). SPM12 and CAT12 toolbox were used to process MRI data and to perform VBM analysis of structural T1-weighted MRI scans. The patients’ versus HV relative GM density was assessed with an uncorrected threshold of p < 0.01. To check for possible correlations, patients’ clinical features and GM maps were regressed.
Results
Compared to HV, CM patients showed 4 clusters of significantly lower GM densities: I) the cerebellar hemispheres/vermis, II) the left occipital areas (BA17/BA18), III) the left middle temporal gyrus, and IV) the left temporal pole /amygdala /pallidum /orbitofrontal cortex. The GM density of cerebellar hemispheres correlated negatively with the years of headache disease, and positively with the number of tablets intake per month.
Conclusion
CM is thus associated with lower GM density in several brain areas known to be involved in nociception/antinociception, multisensory integration, and analgesic dependence. The GM density within the cerebellum was significantly related to longer duration of headache disease and to higher consumption of acute headache medications. We hypothesize that the reduced GM density within the cerebellum may be considered, in conjunction with the results provided by a previous FDG-PET study showing a cerebellar hypermetabolism during medication overuse and its normalization after medication withdrawal, as a predisposing ground on which to develop medication overuse headache.
Disclosure of Interest
None Declared
Imaging
OC-IM-004
Effect of hypoxia on BOLD fMRI response and total cerebral blood flow in migraine with aura patients
Nanna Arngrim1,*, Anders Hougaard1, Henrik Schytz1, Mark Vestergaard2, Josefine Britze1, Faisal M. Amin1, Karsten S. Olsen3, Henrik B. Larsson2, Jes Olesen1 and Messoud Ashina1
1Department of Neurology
2Functional Imaging Unit, Department of Clinical Physiology, Nuclear Medicine and PET
3Department of Neuroanaesthesiology, The Neuroscience Centre, Rigshospitalet Glostrup, Cph S, Denmark
Objectives
Experimentally induced hypoxia triggers migraine and aura attacks in patients suffering from migraine with aura. We investigated the blood-oxygenation level dependent (BOLD) signal response to visual stimulation during hypoxia in migraine aura patients and healthy volunteers.
Methods
In a randomized double-blind crossover study design, 15 migraine with aura patients were allocated to 180 min of hypoxia (capillary oxygen saturation 70 – 75%) or sham (normoxia) on two separate days and 14 healthy volunteers were exposed to hypoxia. The BOLD functional MRI (fMRI) signal response to visual stimulation was measured in the visual cortex ROIs V1-V5. Total cerebral blood flow was measured by phase-contrast mapping (PCM) MRI.
Results
Hypoxia induced a greater decrease in BOLD response to visual stimulation in V1-V4 in migraine with aura patients compared to controls. There was no group difference in hypoxia-induced total CBF increase.
Conclusion
In conclusion, the study demonstrated a greater hypoxia-induced decrease in BOLD response to visual stimulation in migraine with aura patients. We suggest this may represent a hypoxia-induced changed neuronal excitability or abnormal vascular response to visual stimulation, which may explain the increased sensibility to hypoxia in these patients leading to migraine attacks.
Disclosure of Interest
None Declared
Migraine & Cluster Headache
OC-MC-001
Comparative Effects of 3 Doses of Zomitriptan Patch (M207) and Placebo on Pain and Most Bothersome Symptom for the Acute Treatment of Migraine: The Zotrip Study
David Kudrow1,*, Donald Kellerman2, Timothy Smith3 and Stewart Tepper4
1David Geffen Medical School, Santa Monica
2Clinical Development, Zosano Pharma, Fremont
3ClinVest, Springfield
4Geisel School of Medicine, Dartmouth University, Hanover, United States
Objectives
The Zotrip study was designed to compare the efficacy and safety of 1 mg, 1.9 mg and 3.8 mg of M207 (ZP-Zolmitriptan Patch) to placebo in the acute treatment of adults with migraine.
Methods
This was a double-blind, placebo-controlled, randomized trial of three doses of M207 compared to placebo. Subjects with a history of 2–8 migraines per month were enrolled into a run-in period of at least 28 days during which the frequency of migraines was established. Subjects declared their most bothersome symptom (MBS) of photophobia, phonophobia or nausea at study entry. Qualifying subjects were randomly assigned to 1 mg, 1.9 mg, or 3.8 mg of M207 or placebo and instructed to treat the next qualifying migraine with study drug. Subjects recorded migraine symptoms and rescue medication use at 15, 30, 45, 60 minutes, and 2,3,4, 12, 24, and 48 hours. Subjects also recorded patch application observations at 30 min, 4, 12, 24 and 48 hours. Sequential statistical testing was performed beginning with the highest dose and the co-primary endpoints, stepping down to the other doses and endpoints. When significance was not observed for a comparison, subsequent results could no longer be evaluated for statistical significance, and results are expressed as nominal p-values.
Results
589 subjects were enrolled in the trial. Of these 365 met randomization criteria and were dispensed study drug. Of the 365 randomized, 321 treated a migraine with study drug and had at least one post-treatment diary assessment (mITT). The study population was similar across treatment groups: 87% of subjects were female and the mean age was 41.7 years. At the time of treatment, 51% of subjects had severe migraine pain, 49% moderate, 70% had nausea, 37% had aura, and 51% woke up with their migraine. For the co-primary endpoints of pain freedom and MBS freedom, both at 2 hours post treatment, M207 3.8 mg was superior to placebo (pain freedom 41.5% for M207 vs 14.3% for placebo - p = 0.001 and MBS 68.3% for M207 3.8 mg vs 42.9% for placebo, p = 0.0009). M207 1.9 mg was superior to placebo for pain freedom at 2 hours (27.7% for M207 vs 14.3% for placebo, p = 0.0351), but not for MBS. M207 3.8 mg was superior to placebo (nominal p < 0.05) for multiple subgroup analyses including subjects who woke up with their migraine, subjects with nausea at the time of treament and subjects with aura. The most common adverse events were application site reactions (redness and bruising) and >90% of these were considered mild. The most common neurological adverse event was dizziness, reported in 4.4% on M207 3.8 mg subjects.
Conclusion
M207 (ZP-Zolmitriptan) 3.8 mg was effective and well-tolerated for the acute treatment of migraine. Efficacy was robust across several subgroups of traditionally difficult to treat subjects.
Disclosure of Interest
D. Kudrow Conflict with: Zosano Pharma, D. Kellerman Conflict with: Own Stock in Company, Conflict with: Am employed by Zosano, T. Smith Conflict with: Zosano Pharma, S. Tepper Conflict with: Zosano Pharma, Conflict with: Zosano Pharma
Migraine & Cluster Headache
OC-MC-002
Efficacy of Erenumab in Subjects with Episodic Migraine with Prior Preventive Treatment Failure(s)
Peter J. Goadsby1,*, Koen Paemeleire2, Gregor Broessner3, Jan Brandes4, Jan Klatt5, Feng Zhang6, Hernan Picard6, Daniel Mikol6 and Robert Lenz6
1King’s College London, London, United Kingdom
2Ghent University Hospital, Ghent, Belgium
3Medical University of Innsbruck, Innsbruck, Austria
4Nashville Neuroscience Group and Vanderbilt University School of Neurology, Nashville, TN, United States
5Novartis, Basel, Switzerland
6Amgen Inc., Thousand Oaks, CA, United States
Objectives
There is a high unmet need for new preventive migraine treatments, especially for patients who have failed existing migraine therapies. Erenumab is a fully human monoclonal antibody that blocks the calcitonin gene-related peptide receptor. In a large, multicenter, double-blind, placebo controlled, phase 3 study (STRIVE), erenumab 70 mg and 140 mg demonstrated efficacy in subjects with episodic migraine and showed a safety profile similar to placebo. Here we report efficacy results in a subgroup of trial subjects with prior preventive treatment failure(s).
Methods
Subgroup analyses were conducted in subjects from the STRIVE trial who had failed ≥ 1 (n = 369) or ≥ 2 (n = 161) prior preventive treatments due to lack of efficacy and/or intolerability. Analyses included change from baseline in mean monthly migraine days (MMDs) and achievement of ≥ 50% reduction from baseline in MMDs, assessed over weeks 13–24 (months 4, 5, and 6). In the full trial, subjects (N = 955) were randomized 1:1:1 to subcutaneous monthly placebo or erenumab 70 mg or 140 mg for 24 weeks (6 months). P values for subgroup analyses are descriptive and not adjusted for multiple comparisons.
Results
Greater reductions from baseline in MMDs were observed for the erenumab 70 mg and 140 mg groups compared with placebo in both treatment failure subgroups (Table 1). More subjects who received erenumab achieved ≥ 50% reduction in MMD in both subgroups compared with placebo. For the 70 mg group, the odds (95% confidence interval) of achieving ≥ 50% reduction in MMD were 2.9 times higher than that of placebo for both treatment failure subgroups. For the 140 mg group, the odds were 3.1 and 4.5 times higher than placebo, respectively.
Conclusion
Robust treatment effects were observed for both 70 mg and 140 mg erenumab in subjects who had previously failed preventive migraine treatments. For 140 mg, effects were numerically greater in this subpopulation than in the overall trial population, and as in the overall population, erenumab 140 mg showed numerically greater efficacy than erenumab 70 mg. These results suggest that erenumab may have particular utility in this subgroup of patients.
Disclosure of Interest
P. Goadsby Conflict with: Allergan, Amgen, Eli-Lilly and Company, and eNeura, Conflict with: Allergan, Amgen, Eli-Lilly and Company, and eNeura, Ajinomoto Pharmaceuticals Co, Akita Biomedical, Alder Biopharmaceuticals, Autonomic Technologies Inc, Avanir Pharma, Cipla Ltd, Colucid Pharmaceuticals, Ltd, Dr Reddy's Laboratories, Electrocore LLC, Ethicon, US, WL Gore & Associates, Heptares Therapeutics, Novartis, Nupathe Inc, Pfizer Inc, Promius Pharma, Scion, Teva Pharmaceuticals, Trigemina Inc., Conflict with: personal fees from MedicoLegal work, Journal Watch, Up-to-Date, Oxford University Press, K. Paemeleire Conflict with: Amgen, Conflict with: Amgen, Conflict with: Amgen (study investigator), G. Broessner: None Declared, J. Brandes Conflict with: Allergan, Amgen, Clinivest, Teva, Colucid, Zozano, Conflict with: Amgen, Supernus, Conflict with: Depomed, Pernix, TEVA, Avanir, Conflict with: Advisory Board for Avanir, Supernus, TEVA, Supernus, J. Klatt Conflict with: Novartis, Conflict with: Novartis, Conflict with: Novartis, F. Zhang Conflict with: Amgen, Conflict with: Amgen, H. Picard Conflict with: Amgen, Conflict with: Amgen, D. Mikol Conflict with: Amgen, Conflict with: Amgen, R. Lenz Conflict with: Amgen, Conflict with: Amgen
Migraine & Cluster Headache
OC-MC-003
Non-invasive Vagus Nerve Stimulation for the Acute Treatment of Episodic and Chronic Cluster Headache: Findings From the Randomized, Double-blind, Sham-Controlled ACT2 Study
Peter J. Goadsby1, Ilse F. de Coo2,*, Nicholas Silver3, Alok Tyagi4, Fayyaz Ahmed5, Charly Gaul6, Rigmor H. Jensen7, Hans-Christoph Diener8, Eric Liebler9 and Michel D. Ferrari2; ACT2 Study Group
1NIHR-Wellcome Trust CRF, King's College Hospital, London, United Kingdom
2Leiden University Medical Center, Leiden, Netherlands
3Walton Centre for Neurology and Neurosurgery, Liverpool
4The Southern General Hospital, Glasgow
5Hull Royal Infirmary, Hull, United Kingdom
6Migraine and Headache Clinic, Königstein, Germany
7Glostrup Hospital, Glostrup, Denmark
8West German Headache Centre, Essen, Germany
9electroCore, LLC, Basking Ridge, United States
Objectives
Recent study results support the use of non-invasive vagus nerve stimulation (nVNS)
for the acute and prophylactic treatment of cluster headache (CH). In the ACT2 study
(ClinicalTrials.gov: NCT01958125), nVNS (gammaCore®) and a sham device
were compared with regard to efficacy, safety, and tolerability for the acute
treatment of CH attacks in patients with episodic CH (eCH) or chronic CH (cCH). 
Methods
Adults with CH were randomly assigned (1:1) to receive nVNS or sham treatment during the 2-week double-blind phase of the study. Subjects self-administered three consecutive 120-second stimulations to the cervical branch of the vagus nerve at CH attack onset. For attacks not aborted (pain free) within 9 minutes of treatment initiation, a second set of three stimulations was permitted. Subjects were asked to refrain from using rescue treatments for 15 minutes from treatment initiation. The primary end point was the proportion of treated attacks achieving pain-free status (pain score = 0); key secondary end points included change in pain intensity score (scale, 0–4 points) and percentage of subjects with responder status (pain score = 0 or 1) for ≥50% of treated attacks. The measurement time point for all parameters was 15 minutes after treatment initiation. The incidence and seriousness of adverse device effects (ADEs) were monitored to assess safety and tolerability.
Results
Subjects (n = 102; 30 eCH, 72 cCH) from nine EU sites were randomly assigned to receive nVNS (n = 50) or sham (n = 52) treatment. The intent-to-treat population included 48 nVNS-treated subjects (14 eCH, 34 cCH) and 44 sham-treated subjects (13 eCH, 31 cCH). In the total cohort, the proportions of treated attacks that achieved pain-free status at 15 minutes did not differ significantly between treatments (nVNS, 14%; sham, 12%). In the eCH subgroup, nVNS (48%) was significantly superior to sham (6%; P < 0.01), and there was no treatment difference in the cCH subgroup (nVNS, 5%; sham, 13%). The mean decrease in pain intensity score from attack onset to 15 minutes after treatment initiation did not differ significantly between treatments in the total cohort (nVNS, −1.3; sham, −0.9) and was significantly greater with nVNS (−1.7) than sham (−0.6) for the eCH subgroup (P = 0.01); the cCH subgroup showed no significant treatment difference (nVNS, −1.2; sham, −1.0). The proportion of subjects who achieved responder status for ≥50% of treated attacks at 15 minutes was significantly higher with nVNS in the total cohort (nVNS, 40%; sham, 14%; P < 0.01) and the eCH subgroup (nVNS, 64%; sham, 15%; P < 0.01) but not in the cCH subgroup (nVNS, 29%; sham, 13%). The proportion of subjects with ≥1 ADE was similar between the nVNS (18%) and sham (19%) groups, and no ADEs were considered serious.
Conclusion
Acute use of nVNS was superior to sham in patients with eCH but not in those with cCH or in the total cohort, 71% of whom had cCH. These results confirm that nVNS is a safe and effective acute treatment for patients with eCH.
Disclosure of Interest
P. Goadsby Conflict with: Grants from Allergan, Amgen, Eli Lilly and Company, Conflict with: Personal fees from Akita Biomedical; Alder Biopharmaceuticals; Allergan; Amgen; Autonomic Technologies; Avanir Pharmaceuticals; Cipla Ltd; CoLucid Pharmaceuticals, Inc.; Dr. Reddy's Laboratories; electroCore, LLC; eNeura; Eli Lilly and Company; Novartis; Pfizer Inc; Promius Pharma; Quest Diagnostics; Scion; Teva Pharmaceuticals; Trigemina, Inc.; Medico-Legal Journal; Journal Watch; UpToDate; and Oxford University Press. In addition, Dr. Goadsby has a patent for magnetic stimulation for headache pending assigned to eNeura., I. de Coo Conflict with: Travel grants from electroCore, LLC, N. Silver Conflict with: Honoraria from Allergan and electroCore, LLC; investigator fees paid to the Walton Centre, A. Tyagi Conflict with: Honoraria from Allergan and electroCore, LLC, F. Ahmed Conflict with: Honoraria paid to the Migraine Trust and British Association for the Study of Headache for advisory board participation: Allergan; eNeura; electroCore, LLC; and Novartis, C. Gaul Conflict with: Honoraria from Allergan; electroCore, LLC; St. Jude Medical; Grünenthal; Desitin; Bayer; Boehringer Ingelheim; Autonomic Technologies; Reckitt Benckiser; Ratiopharm GmbH; Novartis; Lilly Deutschland; and Hormosan, R. Jensen Conflict with: Given lectures and conducted clinical trials for Autonomic Technologies; Neurocore; and Eli Lilly and Company., H.-C. Diener Conflict with: Research funding from Allergan; Almirall; AstraZeneca; Bayer; electroCore, LLC; GlaxoSmithKline; Janssen-Cilag; MSD; and Pfizer. Additional research support from the German Research Council; the German Ministry of Education and Research; and the European Union., Conflict with: Honoraria for participation in clinical trials and for contributions to advisory boards and oral presentations sponsored by Addex Pharma; Adler; Allergan; Almirall; Amgen; Autonomic Technologies; AstraZeneca; Bayer; Vital; Berlin-Chemie; Boehringer Ingelheim; Bristol-Myers Squibb; Chordate Medical; Coherex Medical; CoLucid Pharmaceuticals; electroCore, LLC; GlaxoSmithKline; Grünenthal; Janssen-Cilag; Labrys Biologics; Eli Lilly and Company; La Roche; 3M Medica; Medtronic; Menarini; Minster Pharmaceuticals; MSD; NeuroScore; Novartis; Johnson & Johnson; Pierre Fabre; Pfizer; Schaper and Brümmer; Sanofi; St. Jude Medical; and Weber & Weber, E. Liebler Conflict with: electroCore, LLC, Conflict with: electroCore, LLC, M. Ferrari Conflict with: Netherlands Organisation for Scientific Research (NWO); the European Community; ZonMw; and the Dutch Heart Foundation, Conflict with: Medtronic, Conflict with: Member of the Editorial Board for Cephalalgia
Migraine & Cluster Headache
OC-MC-004
A Single Intravenous Administration of ALD403 (Eptinezumab) Reduces Use of Triptans Among Patients with Chronic Migraine
David Dodick1,*, Richard Lipton2, Peter J. Goadsby3, Stephen Silberstein4, Roger Cady5 and Joe Hirman6
1Mayo Clinic, Scottsdale
2Neurology, Montefiore Headache Center, Albert Einstein College of Medicine, New York
3Neurology, UCSF, San Francisco
4Neurology, Thomas Jefferson University Headache Center, Philadelphia
5Alder BioPharmaceuticals
6Pacific Northwest Stats, Bothell, United States
Objectives
Patients with chronic migraine (CM) who are high users of triptans (defined as ≥10 days per month) can be difficult to treat. ALD403 (eptinezumab) is a genetically engineered humanized anti-CGRP antibody, for migraine prevention. A single intravenous (IV) administration of ALD403 (eptinezumab) has demonstrated a reduction in migraine frequency with efficacy maintained through 12 weeks. This exploratory analysis was conducted to examine the change in triptan use among patients with CM 12 weeks following administration of ALD403 (eptinezumab).
Methods
Patients with CM aged 18 to 55 years were randomized to receive a single IV infusion of 300mg ALD403 (n = 113) or placebo (n = 116) in this Phase 2 parallel group, double-blind study. The primary endpoint was ≥75% responder rate (RR) for reduction in migraine days in Weeks 1–12. Acute use of triptans was recorded daily during the pre-treatment baseline and throughout the study. Patients completed the Headache Impact Test (HIT-6) questionnaire at baseline, Weeks 4 and 12. Percent of days of triptan use and changes in HIT-6 score for patients classified as high triptan users (patients who use triptans on more than 33% of days (i.e. 10 or more days in every 4 weeks) were assessed by post hoc analysis.
Results
Days of triptan use in ALD403-treated patients exhibited a rapid decline from baseline. The rate of high triptan use decreased from 18.6% to 3.5% during Weeks 1–4 for ALD403-treated patients compared to 14.7% to 12.1% for placebo. The decline in triptan use continued through Week 12. At Week 4, the reduction in HIT-6 score was greater for ALD403 (−9.4) than placebo (−5.5); a trend that continued through Week 12. The reduction in HIT-6 score for ALD403-treated patients was unaffected by baseline triptan use, with high triptan users having a larger change (−10.7) then the ALD403 group as a whole. A similar pattern was seen for the 75% responder rate endpoint, where the ALD403-treated high triptan users had a larger responder rate (38.1%) than the ALD403 group as a whole (36.8%).
Conclusion
High triptan users who received a single IV administration of ALD403 (eptinezumab) demonstrated a rapid and sustained reduction in triptan use through the 12 weeks following the infusion and improved HIT-6 scores. More high triptan users treated with ALD403 also achieved a ≥75% RR at Week 12. These findings suggest ALD403 (eptinezumab) may provide a treatment strategy that enables difficult to treat patients with CM and triptan overuse headache to reduce their use of acute headache medications and minimize headache-related disability.
Disclosure of Interest
D. Dodick Conflict with: Alder BioPharmaceuticals, R. Lipton Conflict with: Alder BioPharmaceuticals, P. Goadsby Conflict with: Alder BioPharmaceuticals, S. Silberstein Conflict with: Alder BioPharmaceuticals, R. Cady Conflict with: Alder BioPharmaceuticals, Conflict with: Alder BioPharmaceuticals, J. Hirman Conflict with: Alder BioPharmaceuticals
Migraine & Cluster Headache
OC-MC-005
Genomic variants related to Verapamil response in the treatment of Migraine
Fred M. Cutrer1,*, Christopher J. Klein1 and Elizabeth J. Atkinson2
1Neurology
2Biostatistics, Mayo Clinic, Rochester, MN, United States
Objectives
At present, there is no biologically based rationale for drug selection among at least five pharmacologically distinct classes of prophylactic treatment in migraine, a disorder that afflicts over 40 million people in the United States. Verapamil is an L-type calcium channel blocker that exerts a prophylactic effect in a subgroup of migraine patients.
Methods
We documented the number of headache days in the four weeks prior to treatment with Verapamil monotherapy and then in the four weeks prior to a return visit after treatment with Verapamil for at least 3 months in 349 patients and obtained a DNA sample from 225 of those patients. Whole Exome sequencing (WES) was performed in 22 patients who were highly responsive to Verapamil (range 58–100% mean 77% decrease in headaches) and in 15 patients who were poorly responsive (range −17 to 20% mean 3% decrease in headache days). After filtering out SNP’s that did not show evidence of differing between these two groups and removing synonymous variants, we identified 588 SNP’s with p < 0.01. We then genotyped 188 different patients in a validation cohort from whom we had Verapamil monotherapy treatment response data using the 524 most significant SNP’s identified by WES and tested for a correlation with reduction in headache days (both absolute arithmetic and percent reduction). We then used all SNP’s that correlated with Verapamil treatment response (p < 0.05) in a pathway analysis to identify potential functional molecular cascades carrying a disproportionate number of Verapamil-migraine implicated SNP’s.
We assessed the change in the number of headache days using the percentage change (Pre-treatment – Post treatment /Pre-treatment values. In this percentage change model, 5.4% (N = 28) of the SNP’s had a p-value < 0.05 and 1.9% (N = 10) had a p-value < 0.01. The table shows the SNP’s with a p-value<0.01. Mean_WT is the mean% change for those with two copies of the more common allele (Wild type). Mean_Carrier is the mean% change for those carrying at least one copy of the minor allele (which is indicated after to SNP number). A negative value indicates an increase in headache days after treatment.
Results
We carried out a pathway analysis using the SNP’s which were most highly correlated with change in headache days after Verapamil monotherapy treatment (p < 0.05). Two pathways were implicated. When SNP’s with p < 0.05 correlation is used, the myo-inositol pathway is implicated. When the SNP’s are further restricted to those with a p < 0.01 then the phospholipase C signaling cascade is implicated.
Conclusion
We propose that response to prophylactic treatment is an element of phenotype that is informative of the molecular pathophysiology of migraine susceptibility in individuals whose migraine is suppressed by a specific drug. We have demonstrated that using WES in highly responsive vs non-responsive subjects we can identify variants that implicate functional molecular cascades that are relevant to the anti-migraine action of the drug investigated. The presence of some of these variants may also ultimately be useful in the prediction of response or non-response to treatment with verapamil. To our knowledge, this is the first work of its kind in migraine.
Disclosure of Interest
None Declared
Secondary Headache
OC-SH-001
GLP-1 Reduces Cerebrospinal Fluid Secretion And Intracranial Pressure: A Novel Treatment For Idiopathic Intracranial Hypertension?
Hannah Botfield1,2,*, Maria Uldall3, Connar Westgate1,2, James Mitchell1,4, Snorre Hagen3, Ana Maria Gonzalez5, David Hodson1,6, Rigmor Jensen3 and Alexandra Sinclair1,4
1Institute of Metabolism and Systems Research, University of Birmingham, Edgbaston
2Centre for Endocrinology, Diabetes and Metabolism, Birmingham Health Partners, Birmingham, United Kingdom
3Danish Headache Center, Clinic of Neurology, Rigshospitalet-Glostrup, University of Copenhagen, Glostrup, Denmark
4Department of Neurology, University Hospitals Birmingham NHS Foundation Trust, Birmingham
5Institute of Inflammation and Ageing
6Centre of Membrane Proteins and Receptors (COMPARE), University of Birmingham, Edgbaston, United Kingdom
Objectives
Current therapies for reducing raised intracranial pressure (ICP) in conditions such as idiopathic intracranial hypertension have limited efficacy and tolerability. As such, there is a pressing need to identify novel drugs. Glucagon-like peptide-1 receptor (GLP-1R) agonists are used to treat diabetes and promote weight loss but have also been shown to affect fluid homeostasis in the kidney. Here, we investigate whether exendin-4, a GLP-1R agonist, is able to modulate cerebrospinal fluid (CSF) secretion at the choroid plexus and subsequently reduce ICP.
Methods
GLP-1R mRNA and protein was assessed by quantitative PCR, immunohistochemistry and fluorescently tagged exendin-4 in human and rat choroid plexus. The effect of exendin-4 on GLP-1R activation and CSF secretion was evaluated in cultured rat choroid plexus epithelial cells using cAMP assays and a Na+ K+ ATPase activity assay. The effect of Exendin-4 on ICP was assessed in adult female rats with normal and raised ICP.
Results
We demonstrated that the GLP-1R is present in human and rat choroid plexus. Exendin-4 significantly increased cAMP levels (2.14 ± 0.61 fold, P < 0.01), part of the GLP-1R signalling pathway, in a concentration-dependant manner and this response could be inhibited by the addition of the GLP-1R antagonist exendin 9–39. Exendin-4 also significantly reduced Na+ K+ ATPase activity, a marker of CSF secretion (39.3 ± 9.4% of control; P < 0.05). Finally, in vivo ICP recording in adult rats demonstrated that subcutaneous administration of 20 µg/kg exendin-4 significantly reduced ICP in normal (65.2 ± 6.6% of baseline; P < 0.01) and raised ICP rats (56.6 ± 5.7% of baseline; P < 0.0001).
Conclusion
We demonstrate that exendin-4 reduces CSF secretion by the choroid plexus and ICP in normal rats and rats with raised ICP. Repurposing existing GLP-1 drugs may represent a novel therapeutic strategy for conditions of raised ICP such as idiopathic intracranial hypertension. Additionally, GLP-1R agonist therapy promotes weight loss which would be advantageous in idiopathic intracranial hypertension.
Disclosure of Interest
None Declared
Secondary Headache
OC-SH-002
DISSECTING THE ANDROGEN EXCESS PHENOTYPE OF WOMEN WITH IDIOPATHIC INTRACRANIAL HYPERTENSION
Catherine Hornby1, Michael O'Reilly1,2, Hannah Botfield1, Connar Westgate1, Keira Markey1,3, Angela Taylor1,2, Carl Jenkinson1,2, Jeremy Tomlinson2,4, Wiebke Arlt1,2 and Alexandra Sinclair1,3,*
1Institute of Systems and Metabolism Research, University of Birmingham
2Centre for Endocrinology, Diabetes and Metabolism, Birmingham Health Partners
3Department of Neurology, University Hospitals Birmingham NHS Foundation Trust, Birmingham
4Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Oxford, United Kingdom
Objectives
Idiopathic intracranial hypertension (IIH) is a devastating neurological condition characterised by elevated intracranial pressure of unknown aetiology. IIH is largely a disease of obese females of reproductive age. The clinical phenotype of IIH overlaps with polycystic ovary syndrome (PCOS), an endocrine condition of young women associated with prevalent obesity, hyperandrogenism and anovulation.
In this study, we aimed to delineate the androgen excess phenotype of IIH women compared to those with PCOS and simple obesity.
Methods
Women with IIH (n = 70), alongside age- and BMI-matched cohorts with PCOS (n = 60) and simple obesity (n = 40), were recruited to an in vivo study. All patients underwent comprehensive metabolic phenotyping and steroid profiling. Serum classic and 11-oxygenated androgens were measured by liquid chromatography-tandem mass spectrometry (LC-MS/MS) and urinary steroid excretion by gas chromatography-mass spectrometry (GCMS). Cerebrospinal fluid (CSF) androgens were quantified by LC-MS/MS in IIH women (n = 49) and a female cohort with non-IIH neurological disease (n = 30). A subset of IIH patients (n = 25) was studied before and after a weight loss intervention.
Results
Serum testosterone was higher in IIH compared to both PCOS and control women (p < 0.001 for both); conversely, serum androstenedione was higher in PCOS women than in IIH (p < 0.001) and controls (p < 0.01). Serum levels of the 11-oxygenated androgen precursors 11b-hydroxyandrostenedione and 11-ketoandrostenedione were increased in PCOS (p < 0.0001), while levels in IIH patients did not differ from controls. Systemic 5a-reductase activity, as measured by the ratio of 5a-tetrahydrocortisol/tetrahydrocortisol, was higher in IIH women compared to both PCOS and controls (p < 0.05 for both). IIH women had increased CSF androstenedione and testosterone compared to controls (all p < 0.0001). PCOS patients had increased insulin resistance, as measured by HOMA-IR (p < 0.05), while HOMA-IR in IIH and controls did not differ.
Following weight loss, serum testosterone and markers of systemic 5a-reductase activity were significantly reduced (p < 0.01), with improvement in clinical markers of IIH such as headache severity, lumbar puncture (LP) pressure and markers of papilloedema, which correlated significantly with systemic 5a-reductase activity.
Conclusion
We show that women with IIH have a distinct androgen excess phenotype compared to PCOS and simple obesity, characterized by higher active serum androgens (increased testosterone), 5a-reductase activity and increased CSF androgens. Weight loss in IIH correlates with a reduction in serum androgens and systemic 5a-reductase activity. Further studies are needed to understand the role of androgen excess in the pathogenesis of IIH.
Disclosure of Interest
None Declared
Secondary Headache
OC-SH-003
Correlations between spinal and brain MRI findings in spontaneous intracranial hypotension
Jr-Wei Wu1,*, Jong-Ling Fuh2,3, Jiing-Feng Lirng3,4, Yen-Feng Wang2,3, Shih-Pin Chen2,3, Shu-Shya Hseu3,5 and Shuu-Jiun Wang2,3
1Department of Neurology, Taipei City Hospital
2Department of Neurology, Taipei Veterans General Hospital
3Faculty of Medicine, National Yang-Ming University School of Medicine
4Department of Radiology
5Department of Anaesthesiology, Taipei Veterans General Hospital, Taipei City, Taiwan, Republic of China
Objectives
The aims of present study were: 1) to determine the association between the spinal and brain MRI signs in spontaneous intracranial hypotension and 2) to examine the application of the Monro-Kellie doctrine in SIH based on the severity of spinal leakage and brain neuroimaging abnormalities.
Methods
A total of 150 SIH patients were recruited in the study. We reviewed the heavily-T2 weighted magnetic resonance myelography (MRM) and brain MRI with or without contrast. The severity of spinal CSF leakage was described as number of segments of anterior, posterior, either anterior or posterior epidural CSF collections, periradicular leaks or C1-C2 extra-spinal leaks. The brain MRI signs included diffuse pachymeningeal enhancement, presence/absence and severity (depicted as angle) of venous distention sign, brain sagging, midbrain-pons angle, angle between vein of Galen and straight sinus, and presence/absence and thickness of subdural hematoma (SDH). Since the brain MRI signs may be interfered by SDH, we also performed the subgroup analyses based on presence or absence of SDH.
Results
In patients with SIH (n = 150), the length of anterior epidural CSF collection was negatively correlated with midbrain-pons angle (r = −0.39, p < 0.001). Patients with venous distention sign had longer segments of posterior epidural CSF collections (13.2 ± 5.1 vs. 10.3 ± 4.3, p = 0.008) and epidural CSF collection (either anterior or posterior) (15.5 ± 5.3 vs. 13.1 ± 4.5, p = 0.03). Other brain MRI signs had no association with severity of spinal CSF leakage. In patients without SDH (n = 111), the length of anterior epidural CSF collection correlated with mid-brain pons angle (r = −0.40, p < 0.001). Longer segments of epidural CSF collection associated with more severe venous distention (r = 0.23, p = 0.016) and presence of venous distension sign (15.8 ± 4.9 vs. 12.9 ± 4.5, p = 0.01). In patients with SDH (n = 39), no brain MRI signs associated with spinal MRI findings.
Conclusion
Our study showed severity of venous distension was associated with severity of spinal CSF leak in SIH patients without SDH, which coincides with the Monro-Kellie doctrine. Closure of midbrain-pons angle reflects the severity of spinal CSF leak in all SIH patients. Therefore, diencephalic-mesencephalic deformity may be an alternative compensatory mechanism in spinal CSF leak.
Disclosure of Interest
None Declared
Secondary Headache
OC-SH-004
Headaches in the Idiopathic Intracranial Hypertension Treatment Trial: Six Month Outcomes
Deborah I. Friedman1,*, Peter Quiros2, Prem Subramanian3, Luis J. Mejico4 and Michael McDermott5; NORDIC IIHTT Study Group
1Neurology & Neurotherapeutics and Ophthalmology, University of Texas Southwestern Medical Center, Dallas
2Ophthalmology, Doheny Eye Institute, Los Angeles
3Ophthalmology, University of Colorado, Denver
4Neurology, SUNY Upstate Medical University, Syracuse
5Biostatistics and Computational Biology, University of Rochester, Rochester, United States
Objectives
Headache is the most common symptom of IIH. The IIHTT prospectively enrolled 165 participants with mild visual field loss to assess whether acetazolamide (ACZ) plus dietary management was superior to placebo (PBO) tablets plus dietary management in improving visual function1. We report the headache outcomes of participants in the IIHTT.
Methods
Participants completed the Headache Impact Test -6 (HIT) and headache symptom questionnaires at each study visit. The Short Form-36 (SF-36) and National Eye Institute Visual Function Questionnaire (NEI-VFQ-25) and neuro-ophthalmic supplement (NOS) assessed quality of life at baseline and at 6 months2.
Group comparisons pertaining to HIT-6 total score were performed using two-sample t-tests. Group comparisons of proportions were performed using chi-square tests. Bivariate associations between variables were assessed using Spearman rank correlation coefficients. Logistic regression analyses determined the associations between baseline variables and the development of headache after baseline.
Results
139 (84%) enrollees had headaches at baseline and another 21 (13%) reported headaches in follow-up. 69% in the ACZ group and 68% in the PBO group had persistent headaches at 6 months. There was no statistically significant difference in HIT-6 scores between treatment groups at 6 months. Development of headache after enrollment was not associated CSF opening pressure (OP) at baseline (OR 0.997, 95% CI 0.991-1.003, p = 0.32), baseline papilledema grade (OR 1.88, 95% CI 0.74–4.81, p = 0.19), or baseline BMI (OR 1.02, 95% CI 0.97–1.08, p = 0.39). HIT-6 score at 6 months was not significantly correlated with CSF OP at 6 months (r = 0.12, p = 0.29) or the maximum dose of study drug taken (r = −0.09, p = 0.48) or weight lost (r = 0.02, p = 0.80). THE NEI-VFQ-25 total score and NOS, the SF-36 physical and mental component summaries and SF-36 subscale scores were significantly correlated with the number of headache days at 6 months.
Conclusion
Our findings provide class I evidence that CSF pressure and headaches are independent features of IIH.
Disclosure of Interest
None Declared
REFERENCES
Trainees Tournament
OC-TR-001
A clinical decision support system using multi-modality imaging data for migraine classification
Nathan Gaw1,*, Todd J. Schwedt2, Catherine D. Chong2, Teresa Wu1 and Jing Li1
1Computing, Informatics, and Decision Systems Engineering, Arizona State University, Tempe
2Neurology, Mayo Clinic Arizona, Phoenix, United States
Objectives
Readily available imaging technologies, such as magnetic resonance imaging (MRI), utilize multi-modality imaging sequences to collect complementary information for the same patient. These imaging modalities provide data that describe different properties of the brain including multiple measures of brain structure and function. Extensive research has been done in multi-modality imaging data fusion and integration. However, the existing research has not yet been transformed into a clinical decision support system due to the lack of flexibility, sufficient accuracy, and interpretability. The objective of this study was to develop a multi-modality imaging based diagnostic decision support system (MMI-DDS) that overcomes the limitations of existing research and integrates multi-modality imaging data for migraine classification.
Methods
The MMI-DDS included three inter-connected components: (1) a modality-wise principal component analysis (PCA) that reduces data dimensionality and meanwhile provides the flexibility for opting out tedious and error-prone co-registration for multi-modality images; (2) a novel constrained particle swarm optimization (cPSO) based classifier that is built upon the joint set of the principal components (PCs) from all the imaging modalities and achieves nearly-optimal diagnostic accuracy; (3) a clinical utility engine that employs inverse operations to identify contributing imaging features (i.e. measures of brain structure or function) for classifying migraine. To validate MMI-DDS, we applied it to a migraine dataset with multi-modality structural and functional MRI data including measures of cortical thickness, surface area, volume, and resting-state functional connectivity. Imaging was performed on 3T MRI scanners at Mayo Clinic Arizona and Washington University School of Medicine in St. Louis.
Table:
Results
Data were available from 57 individuals with migraine and 49 healthy controls. Migraine and healthy control cohorts were of similar ages (migraine: 36.6 ±11.5 years vs. healthy: 36.1 ± 11.1 years; p = 0.8214) and gender distribution (migraine: 44 F, 13 M vs. healthy: 35 F, 14 M; p = 0.7515). The migraine cohort averaged 7.6 ± 5.3 headache days per month and had migraine for an average of 16.7 ± 10.4 years. MMI-DDS showed significantly improved diagnostic accuracy compared to single imaging modalities alone. (see Table) Using a two-sample t-test, the cross validation error of MRI and fMRI data combined was significantly lower than MRI alone with p values of 0.0062, 2.2 × 10−5 and 2.8 × 10−4 for linear discriminant analysis (LDA), quadratic discriminant analysis (QDA), and linear support vector machine (LSVM) classifiers, respectively. Among the three classifiers, LSVM achieved the highest classification accuracy of 83%, using MRI and fMRI data combined.
Conclusion
A high accuracy for migraine classification was achieved by integrating structural and functional imaging modalities together. The accuracy of the multi-modality imaging based classifier was significantly higher than the accuracy achieved when using single imaging modalities alone. Future research (1) will investigate if even better classification accuracy can be achieved by the inclusion of additional imaging modalities, (2) will extend the system’s capability to classify subtypes of migraine, and (3) will aim to develop models that predict clinical variables related to migraine.
Disclosure of Interest
None Declared
Trainees Tournament
OC-TR-002
Topiramate inhibits thalamic activity during trigeminal pain in humans
Julia M. Hebestreit1,* and Arne May2
1Department of Systems Neuroscience
2Department of Systems Neuroscience, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
Objectives
Topiramate (TPM) is a first-choice medication in migraine preventive treatment1. Although very effective, little is known about its underlying central mechanism of action in migraine treatment. The aim of this study was to investigate the effect of TPM on trigeminal pain processing in healthy human subjects.
Methods
The effect of TPM on experimental trigeminal nociceptive processing, compared to placebo (PBO), was examined using fMRI. In a within subject and placebo-controlled design, 23 healthy subjects received either TPM or PBO and a standardized nociceptive trigeminal stimulation2,3. TPM and PBO were administered orally in a randomized, crossover, double blind procedure. Subjects with a history of neurological, psychiatric or pain disorders were excluded. Blood samples were obtained to determine the plasma concentration of TPM.
Results
The mean plasma concentration of TPM was 1.38 mg/L (SD = 0.8). Treatment-emergent adverse events were reported by 16 subjects. These included mild to moderate dizziness, difficulty with concentration, paresthesia and fatigue. No significant differences in the behavioral responses of the intensity and (un-)pleasantness of the painful stimuli were observed between TPM and the PBO. Under PBO a significantly increased blood oxygen level-dependent (BOLD) signal in the thalamus (SVC: p < 0.05 FWE-corrected) and other pain processing areas (whole brain: p < 0.001 uncorrected) was observed, compared to TPM. In a second analysis we found that TPM treatment was associated with an enhanced functional coupling between the thalamus and several cortical and subcortical regions such as the bilateral Precuneus, posterior cingulate cortex, secondary somatosensory cortex and cerebellum.
Conclusion
The main finding of this study is that the thalamus is significantly more active during PBO compared to TPM during trigeminal pain. At the same time the functional coupling of the thalamus to other pain transmitting areas changes as well. This suggests that TPM exhibits modulating effects on the thalamo-cortical networks processing trigeminal pain. Hence, the preventive migraine effect of TPM may be mediated by an inhibiting effect on these thalamo-cortical networks4.
Disclosure of Interest
None Declared
References
Trainees Tournament
OC-TR-003
The clock gene CRY1 is associated with cluster headache in Sweden
Carmen Fourier1,*, Caroline Ran1, Anna Steinberg2, Christina Sjöstrand2, Elisabet Waldenlind2 and Andrea Carmine Belin1
1Neuroscience, Karolinska Institutet
2Clinical Neuroscience, Karolinska University Hospital, Stockholm, Sweden
Objectives
Cluster headache (CH) is a devastating neurovascular disorder characterized by a striking circadian and circannual attack pattern. Genetic studies suggest an association between CH and the CLOCK gene, which has a critical role in the generation of circadian rhythms. Other key regulators of the circadian clock are for example cryptochrome (CRY) 1 and 2. The genes encoding CRY1 and CRY2 have been reported to be associated with several neurological disorders, such as depression, bipolar disorder, and schizophrenia. In this study, we investigated a possible association of the CRY genes with CH.
Methods
We screened 518 CH patients and 581 controls for four different single nucleotide polymorphisms (SNPs) in the CRY genes (rs2287161 and rs8192440 in CRY1, rs10838524 and rs1554338 in CRY2) using pre-designed TaqMan® assays and compared genotype, allele, and haplotype frequencies between the two groups. In addition, we analyzed CRY1 gene expression in fibroblasts, obtained from 12 CH patients and 8 controls, using qRT-PCR.
Results
We found an association between the exonic CRY1 variant rs8192440 and CH on the allelic level (P = 0.0048). The minor allele A is more common in controls than in CH patients. The association becomes even stronger when stratifying the patient group for diurnal rhythmicity of attack occurrence (P = 0.0036). When comparing CRY1 gene expression levels between CH patients and controls, the relative CRY1 gene expression was significantly higher in CH patients (P = 0.0001).
Conclusion
A genetic variant in CRY1 which leads to a synonymous amino acid change in the CRY1 protein is associated with CH in our Swedish case-control material. The minor allele of this SNP seems to be a protective factor. Furthermore, CRY1 gene expression levels are significantly higher in CH patients compared to controls. By which mechanisms rs8192440 may affect the CRY1 gene remains to be determined. Increased CRY1 expression may trigger the periodically reoccurring CH attacks in a yet unknown manner. Although a lot more research needs to be done, this study points to a role of the clock gene CRY1 in the pathophysiology of CH.
Disclosure of Interest
None Declared
Trainees Tournament
OC-TR-004
Functional characteristics of non-invasively optogenetically induced csd in fhm1 mutant mice
Inge C. M. Loonen1,*, Thijs B. Houben2, Maarten Schenke1, Michel D. Ferrari2, Gisela M. Terwindt2, Rob A. Voskuyl1, Arn M. J. M. van den Maagdenberg1,2 and Else A. Tolner1,2
1Human Genetics
2Neurology, LUMC, Leiden, Netherlands
Objectives
Cortical spreading depression (CSD) is the likely correlate of the migraine aura. In experimental models CSD is typically studied using highly invasive CSD-induction methods. Earlier it was shown that susceptibility to KCl or electrically induced CSD is enhanced in familial hemiplegic migraine type 1 (FHM1) transgenic mice expressing human pathogenic R192Q or S218L missense mutations in voltage-gated CaV2.1 calcium channels. With optogenetics technology, neurons expressing light-sensitive channelrhodopsin-2 ion channels (ChR2) can be depolarized by blue light. This can be used in vivo to activate deep layer cortical neurons by using mice expressing ChR2 under control of the neuronal Thy1 promoter (Thy1-ChR2 mice). Previously, we used this approach for non-invasive induction of CSD in freely behaving Thy1-ChR2 mice by cortical illumination through the intact skull. We here will compare characteristics of non-invasively induced CSD by optogenetics of Thy1-ChR2 ‘wild-type' mice and Thy1-ChR2 mice cross-bred with FHM1 R192Q or S218L mice.
Methods
Under anesthesia, a 400-µm optic fiber for CSD induction was placed on the skull overlaying the visual cortex for light-activation while intracortical platinum electrodes were implanted in the motor and parietal cortex for CSD and multi-unit activity recordings and additional skull laser Doppler probes for non-invasive CSD detection. In awake freely behaving mice, CSD was induced using blue light pulses (470 nm) delivered at different intensities and durations. Simultaneous video-recordings allowed for behavioral analysis and wire grip tests were performed to assess motor function related to CSD. Experiments were approved by the LUMC Animal Experiment Ethics Committee with care and handling according to the Dutch Law on animal experimentation.
Results
In wild-type mice and R192Q mutants, optogenetic stimulation resulted in a single CSD wave, whereas multiple CSD waves were observed in the majority of S218L mutants. CSD propagation rate was elevated in FHM1 mice compared to wild-type, most pronounced in S218L mutants. CSD caused a short increase in active behavior followed by prolonged reduction. Motor function was transiently and unilaterally suppressed following CSD.
Conclusion
Optogenetic CSD induction has significant advantages over current CSD models in that CSD events can be elicited repeatedly in freely behaving mice in a non-invasive manner and is able to reveal changes in FHM1 mutant mice.
Disclosure of Interest
None Declared
Trainees Tournament
OC-TR-005
Pleasure and pain: exploring neurobiological mechanisms of food craving before migraine pain
Margarida Martins-Oliveira1,2,*, Simon Akerman1, Philip R. Holland2, Isaura Tavares3 and Peter J. Goadsby1,2
1Headache Group, Department of Neurology, University of California San Francisco, San Francisco, United States
2Headache Group, Department of Basic and Clinical Neuroscience, Institute of Psychology, Psychiatry and Neuroscience, King’s College London, London, United Kingdom
3Pain Research Group, Department of Biomedicine, Faculty of Medicine of University of Porto and i3S - Institute of Investigation and Innovation in Health, Porto, Portugal
Objectives
Migraine premonitory symptoms can include food craving and imaging studies show increased activation of the ventral tegmental area (VTA) during the premonitory phase. Since VTA dopaminergic neurons are involved in hedonic feeding, we aimed to determine the effect of pharmacological manipulation of the VTA on the trigeminocervical complex (TCC) neuronal activity in response to nociceptive activation, mechanical facial stimulation, as well as the effect on glucose metabolism.
Methods
Male Sprague Dawley® rats (n = 41) were anesthetized, the parietal bone was removed over the middle meningeal artery for dura mater electrical stimulation, and over the midbrain for local microinjections. Using in vivo electrophysiology, TCC neurons were recorded before and after administration into the VTA of glutamate, a dopamine D2/D3 receptor agonist (quinpirole), naratriptan, pituitary adenylate cyclase activating peptide (PACAP38) or saline as vehicle control. Moreover, mechanical facial stimulation was performed using innocuous and noxious stimuli throughout the study. Additionally, glycemic levels were measured before and after microinjection of drugs.
Results
Dural-evoked neuronal firing in the TCC was significantly reduced by glutamate (p < 0.05, max inhibition 37%), quinpirole (p < 0.005, max inhibition 19%), naratriptan (p < 0.005, max inhibition 38%) and PACAP38 (p < 0.05, max inhibition 30%). Noxious mechanical stimulation was significantly inhibited by glutamate (p < 0.05, max inhibition 30%), quinpirole (p < 0.005, max inhibition 35%), naratriptan (p < 0.005, max inhibition 56%) and PACAP38 (p < 0.05, max inhibition 40%). Innocuous mechanical stimulation was significantly inhibited by naratriptan (p < 0.005, max inhibition 48%) and PACAP38 (p < 0.05, max inhibition 41%); but not glutamate or quinpirole (p > 0.05). Regarding blood glucose levels, local VTA microinjection of glutamate and naratriptan significantly decreased (p < 0.05); quinpirole significantly increased (p < 0.05); and PACAP38 had no significant effect (p > 0.05) on blood glucose levels after 60min post-injection. Vehicle control injections had no significant effect on TCC nociceptive neuronal firing, mechanical facial responses or blood glucose levels (p > 0.05).
Conclusion
These results show that VTA is able to modulate trigeminovascular nociceptive activity, as well as central glucose metabolism in a migraine animal model. Moreover, we confirm that naratriptan can act within the VTA to modulate TCC neuronal firing and glucose metabolism. Importantly, we show that PACAP38 plays an antinociceptive role when microinjected into the VTA. The VTA is also capable of modulating facial mechanical responses in a migraine animal model, suggesting a physiological role in the control of mechanisms underlying symptoms of allodynia and hyperalgesia. Overall, these results could be explained by indirect projections to the TCC, via neuronal connections with other pain modulating structures. Furthermore, dysfunctional VTA dopaminergic activity in migraineurs could potentially disrupt feeding mechanisms and affect downstream pain pathways.
Acknowledgments
This work was supported by the Portuguese Fundação para a Ciência e Tecnologia (FCT) and the EUROHEADPAIN European Union FP7.
Disclosure of Interest
M. Martins-Oliveira: None Declared, S. Akerman Conflict with: Dr. Akerman reports, unrelated to this report, grants from Electrocore LLC., P. Holland Conflict with: Dr. Holland reports, unrelated to this report, grants from Amgen., Conflict with: Dr. Holland reports, unrelated to this report, honoraria and travel expenses in relation to educational duties from Allergan and Almirall, I. Tavares: None Declared, P. Goadsby Conflict with: Dr. Goadsby reports, unrelated to this report, grants and personal fees from Allergan, Amgen, and Eli-Lilly and Company, Conflict with: Dr. Goadsby reports, unrelated to this report, personal fees from Akita Biomedical, Alder Biopharmaceuticals, Autonomic Technologies Inc, Avanir Pharma, Cipla Ltd, Colucid Pharmaceuticals, Ltd, Dr Reddy's Laboratories, eNeura, Electrocore LLC, Novartis, Pfizer Inc, Promius Pharma, Quest Diagnostics, Scion, Teva Pharmaceuticals, Trigemina Inc., Scion, Conflict with: Dr. Goadsby reports, unrelated to this report, personal fees from MedicoLegal work, Journal Watch, Up-to-Date, Oxford University Press; and in addition, Dr. Goadsby has a patent Magnetic stimulation for headache pending assigned to eNeura.
Trainees Tournament
OC-TR-006
DIFFERENTIAL CELLULAR LOCALISATION OF OREXIN RECEPTORS IN THE PERIAQUEDUCTAL GRAY
Lauren C. Strother1,*, Peter J. Goadsby1 and Philip R. Holland1
1Basic and Clinical Neuroscience, King's College London, London, United Kingdom
Objectives
The orexins are two neuropeptides that are exclusively synthesised in the hypothalamus and play a key role in the modulation of feeding, sleep-wake regulation and stress responses suggesting a potential role in migraine. In support of an orexinergic involvement in migraine, we have previously identified a differential trigeminovascular response to orexinergic modulation in descending pain networks. Our unpublished data shows that microinjection of orexin A into the ventrolateral periaqueductal gray (vlPAG) in the rat is anti-nociceptive by inhibiting medullary trigeminovascular neural responses to meningeal electrical stimulation, while conversely, orexin B facilitates these responses. Orexin peptides exhibit a preferential affinity for two orexin receptors (OX1R and OX2R), and therefore, to account for these differential responses, we hypothesized this was likely due to differential orexin receptor expression in the vlPAG. Here, we sought to characterise the cellular localisation of the two orexin receptors in the vlPAG of the rat.
Methods
We used fluorescent immunohistochemistry with avidin-biotin amplification in order to visualise the cellular expression of the two orexin receptors (OX1R and OX2R) in the vlPAG, while also co-localising receptor expression with the expression of orexin peptides A and B.
Results
We demonstrate that the OX1R is preferentially expressed in neural cell bodies within the vlPAG while the OX2R is preferentially expressed on cell fibres. Both OX1R expressing cell bodies and OX2R expressing fibres have close appositions to orexin expressing fibres projecting from the hypothalamus.
Conclusion
Hypothalamic orexinergic expressing neurons send projections to the vlPAG where they contact OX1R and OX2R expressing cell bodies and fibres, respectively. This differential receptor localisation likely underlies the previously identified differential modulation of medullary trigeminovascular neural responses to meningeal electrical stimulation following orexin A and B administration into the vlPAG.
This work is supported by the Medical Research Council (MR/P006264/1), FP7 project EUROHEADPAIN (no. 602633) and PhD funding from The Migraine Trust.
Disclosure of Interest
None Declared