Spinal cord injury (SCI) patients sustain significant functional impairments; this is causally related to restricted neuronal regeneration after injury. The ensuing reactive gliosis, inflammatory cascade, and glial scar formation impede axonal regrowth. Although systemic anti-inflammatory agents (steroids) have been previously administered to counteract this, no current therapeutic is approved for post-injury neuronal regeneration, in part because of related side effects. Likewise, therapeutic systemic estrogen levels exhibit neuroprotective properties, but dose-dependent side effects are prohibitive. The current study thus uses low-dose estrogen delivery to the spinal cord injury (SCI) site using an agarose gel patch embedded with estrogen-loaded nanoparticles. Compared to controls, spinal cords from rodents treated with nanoparticle site-directed estrogen demonstrated significantly decreased post-injury lesion size, reactive gliosis, and glial scar formation. However, axonal regeneration, vascular endothelial growth factor production, and glial-cell–derived neurotrophic factor levels were increased with estrogen administration. Concomitantly improved locomotor and bladder functional recovery were observed with estrogen administration after injury. Therefore, low-dose site-directed estrogen may provide a future approach for enhanced neuronal repair and functional recovery in SCI patients.
Get full access to this article
View all access options for this article.
References
1.
CreggJ.M., DePaulM.A., FilousA.R., LangB.T., TranA., and SilverJ. (2014). Functional regeneration beyond the glial scar. Exp. Neurol. 253, 197–207.
2.
SiebertJ.R., Conta SteenckenA., and OsterhoutD.J. (2014). Chondroitin sulfate proteoglycans in the nervous system: inhibitors to repair. Biomed. Res. Int. 2014, 845323.
3.
FehlingsM.G., and HawrylukG.W. (2010). Scarring after spinal cord injury. J. Neurosurg. Spine, 13, 165–167.
4.
BreslinK., and AgrawalD. (2012). The use of methylprednisolone in acute spinal cord injury: a review of the evidence, controversies, and recommendations. Pediatr. Emerg. Care, 28, 1238–1245.
5.
LammertseD.P. (2013). Clinical trials in spinal cord injury: lessons learned on the path to translation. The 2011 International Spinal Cord Society Sir Ludwig Guttmann Lecture. Spinal Cord, 51, 2–9.
6.
SchroederG.D., KwonB.K., EckJ.C., SavageJ.W., HsuW.K., and PatelA.A. (2014). Survey of Cervical Spine Research Society members on the use of high-dose steroids for acute spinal cord injuries. Spine, 39, 971–977.
7.
SamantarayS., SmithJ.A., DasA., MatzelleD.D., VarmaA.K., RayS.K., and BanikN.L. (2011). Low dose estrogen prevents neuronal degeneration and microglial reactivity in an acute model of spinal cord injury: effect of dosing, route of administration, and therapy delay. Neurochem. Res. 36, 1809–1816.
8.
YuneT.Y., KimS.J., LeeS.M., LeeY.K., OhY.J., KimY.C., MarkelonisG.J., and OhT.H. (2004). Systemic administration of 17β-estradiol reduces apoptotic cell death and improves functional recovery following traumatic spinal cord injury in rats. J. Neurotrauma, 21, 293–306.
9.
SiriphornA., DunhamK.A., ChompoopongS., and FloydC.L. (2012). Postinjury administration of 17β-estradiol induces protection in the gray and white matter with associated functional recovery after cervical spinal cord injury in male rats. J. Comp. Neurol. 520, 2630–2646.
10.
ElkabesS., and NicotA.B. (2014). Sex steroids and neuroprotection in spinal cord injury: a review of preclinical investigations. Exp. Neurol. 259, 28–37.
11.
KippM., BergerK., ClarnerT., DangJ., and BeyerC. (2012). Sex steroids control neuroinflammatory processes in the brain: relevance for acute ischaemia and degenerative demyelination. J. Neuroendocrinol. 24, 62–70.
12.
SamantarayS., SribnickE.A., DasA., ThakoreN.P., MatzelleD., YuS.P., RayS.K., WeiL, and BanikN.L. (2010). Neuroprotective efficacy of estrogen in experimental spinal cord injury in rats. Ann. N. Y. Acad. Sci. 1199, 90–94.
13.
DayN.L., FloydC.L., D'AlessandroT.L., HubbardW.J., and ChaudryI.H. (2013). 17beta-estradiol confers protection after traumatic brain injury in the rat and involves activation of G protein-coupled estrogen receptor 1. J. Neurotrauma, 30, 1531–1541.
14.
AslS.Z., KhaksariM., KhachkiA.S., ShahrokhiN., and NourizadeS. (2013). Contribution of estrogen receptors alpha and beta in the brain response to traumatic brain injury. J. Neurosurg. 119, 353–361.
15.
ZlotnikA., LeibowitzA., GurevichB., OhayonS., BoykoM., KleinM., KnyazerB., ShapiraY, and TeichbergV.I. (2012). Effect of estrogens on blood glutamate levels in relation to neurological outcome after TBI in male rats. Intensive Care Med. 38, 137–144.
16.
ArdeltA.A., CarpenterR.S., LoboM.R., ZengH., SolankiR.B., ZhangA., KuleszaP., and PikeM.M. (2012). Estradiol modulates post-ischemic cerebral vascular remodeling and improves long-term functional outcome in a rat model of stroke. Brain Res. 1461, 76–86.
17.
ZhangQ.G., RazL., WangR., HanD., De SevillaL., YangF., VadlamudiR.K., and BrannD.W. (2009). Estrogen attenuates ischemic oxidative damage via an estrogen receptor alpha-mediated inhibition of NADPH oxidase activation. J. Neurosci. 29, 13823–13836.
18.
MerchenthalerI., DellovadeT.L., and ShughrueP.J. (2003). Neuroprotection by estrogen in animal models of global and focal ischemia. Ann. N. Y. Acad. Sci. 1007, 89–100.
19.
LidegaardO., EdstromB., and KreinerS. (2002). Oral contraceptives and venous thromboembolism: a five-year national case-control study. Contraception, 65, 187–196.
20.
LaCroixA.Z., ChlebowskiR.T., MansonJ.E., AragakiA.K., JohnsonK.C., MartinL., MargolisK.L., StefanickM.L., BrzyskiR., CurbJ.D., HowardB.V., LewisC.E., and Wactawski-WendeJ. (2011). Health outcomes after stopping conjugated equine estrogens among postmenopausal women with prior hysterectomy: a randomized controlled trial. JAMA, 305, 1305–1314.
21.
GabizonA., and MartinF. (1997). Polyethylene glycol-coated (pegylated) liposomal doxorubicin. Rationale for use in solid tumours. Drugs, 54, 15–21.
22.
ChvatalS.A., KimY.T., Bratt-LealA.M., LeeH., and BellamkondaR.V. (2008). Spatial distribution and acute anti-inflammatory effects of Methylprednisolone after sustained local delivery to the contused spinal cord. Biomaterials, 29, 1967–1975.
23.
CoxA., VarmaA., BarryJ., VertegelA., and BanikN. (2015). Nanoparticle estrogen in rat spinal cord injury elicits rapid anti-inflammatory effects in plasma, cerebrospinal fluid, and tissue. J. Neurotrauma, 32, 1413–1421.
24.
CoxA., VarmaA., and BanikN. (2015). Recent advances in the pharmacologic treatment of spinal cord injury. Metab. Brain Dis. 30, 473–482.
25.
SribnickE.A., WingraveJ.M., MatzelleD.D., WilfordG.G., RayS.K., and BanikN.L. (2005). Estrogen attenuated markers of inflammation and decreased lesion volume in acute spinal cord injury in rats. J. Neurosci. Res. 82, 283–293.
26.
LangB.T., CreggJ.M., DePaulM.A., TranA.P., XuK., DyckS.M., MadalenaK.M., BrownB.P., WengY.L., LiS., Karimi-AbdolrezaeeS., BuschS.A., ShenY., and SilverJ. (2015). Modulation of the proteoglycan receptor PTPσ promotes recovery after spinal cord injury. Nature, 518, 404–408.
27.
PerotP.L.Jr., LeeW.A., HsuC.Y., HoganE.L., CoxR.D., and GrossA.J. (1987). Therapeutic model for experimental spinal cord injury in the rat: I. Mortality and motor deficit. Cent. Nerv. Syst. Trauma, 4, 149–159.
28.
RayS.K., MatzelleD.C., WilfordG.G., HoganE.L., and BanikN.L. (2000). E-64-d prevents both calpain upregulation and apoptosis in the lesion and penumbra following spinal cord injury in rats. Brain Res. 867, 80–89.
29.
MaximovV.D., ReukovV.V., BarryJ.N., CochraneC., and VertegelA.A. (2010). Protein-nanoparticle conjugates as potential therapeutic agents for the treatment of hyperlipidemia. Nanotechnology, 21, 265103.
30.
MakadiaH.K., and SiegelS.J. (2011). Poly lactic-co-glycolic acid (PLGA) as biodegradable controlled drug delivery carrier. Polymers (Basel) 3, 1377–1397.
31.
SamantarayS., DasA., MatzelleD.C., YuS.P., WeiL., VarmaA., RayS.K., and BanikN.L. (2016). Administration of low dose estrogen attenuates gliosis and protects neurons in acute spinal cord injury in rats. J. Neurochem. 136, 1064–1073.
32.
SamantarayS., DasA., MatzelleD.C., YuS.P., WeiL., VarmaA., RayS.K., and BanikN.L. (2016). Administration of low dose estrogen attenuates persistent inflammation, promotes angiogenesis, and improves locomotor function following chronic spinal cord injury in rats. J. Neurochem. 137, 604–617.
33.
BassoD.M., BeattieM.S., and BresnahanJ.C. (1995). A sensitive and reliable locomotor rating scale for open field testing in rats. J. Neurotrauma, 12, 1–21.
34.
SribnickE.A., WingraveJ.M., MatzelleD.D., RayS.K., and BanikN.L. (2003). Estrogen as a neuroprotective agent in the treatment of spinal cord injury. Ann. N. Y. Acad. Sci. 993, 125–133.
35.
SiebertJ.R., and OsterhoutD.J. (2011). The inhibitory effects of chondroitin sulfate proteoglycans on oligodendrocytes. J. Neurochem. 119, 176–188.
36.
KawanoH., Kimura-KurodaJ., KomutaY., YoshiokaN., LiH.P., KawamuraK., LiY., and RaismanG. (2012). Role of the lesion scar in the response to damage and repair of the central nervous system. Cell Tissue Res. 349, 169–180.
37.
SofroniewM.V. (2009). Molecular dissection of reactive astrogliosis and glial scar formation. Trends Neurosci. 32, 638–647.
GenselJ.C., and ZhangB. (2015). Macrophage activation and its role in repair and pathology after spinal cord injury. Brain Res. 1619, 1–11.
40.
ZhouX., HeX., and RenY. (2014). Function of microglia and macrophages in secondary damage after spinal cord injury. Neural Regen. Res. 9, 1787–1795.
41.
MaS.F., ChenY.J., ZhangJ.X., ShenL., WangR., ZhouJ.S., HuJ.G., and LüH.Z. (2015). Adoptive transfer of M2 macrophages promotes locomotor recovery in adult rats after spinal cord injury. Brain Behav. Immun. 45, 157–170.
42.
ZhangB., BaileyW.M., KopperT.J., OrrM.B., FeolaD.J., and GenselJ.C. (2015). Azithromycin drives alternative macrophage activation and improves recovery and tissue sparing in contusion spinal cord injury. J. Neuroinflammation, 12, 218.
43.
WannerI.B., AndersonM.A., SongB., LevineJ., FernandezA., Gray-ThompsonZ., AoY., and SofroniewM.V. (2013). Glial scar borders are formed by newly proliferated, elongated astrocytes that interact to corral inflammatory and fibrotic cells via STAT3-dependent mechanisms after spinal cord injury. J. Neurosci. 33, 12870–12886.
44.
Leal-FilhoM.B. (2011). Spinal cord injury: from inflammation to glial scar. Surg. Neurol. Int. 2, 112.
45.
ShearerM.C., and FawcettJ.W. (2001). The astrocyte/meningeal cell interface—a barrier to successful nerve regeneration?. Cell Tissue Res. 305, 267–273.
46.
HabibP., SlowikA., ZendedelA., JohannS., DangJ., and BeyerC. (2014). Regulation of hypoxia-induced inflammatory responses and M1-M2 phenotype switch of primary rat microglia by sex steroids. J. Mol. Neurosci. 52, 277–285.
47.
BradburyE.J., and BurnsideE.R. (2019). Moving beyond the glial scar for spinal cord repair. Nat. Commun. 10, 3879.
48.
LiddelowS.A., and BarresB.A. (2017). Reactive astrocytes: production, function, and therapeutic potential. Immunity, 46, 957–967.
49.
SpenceR.D., HambyM.E., UmedaE., ItohN., DuS., WisdomA.J., CaoY., BondarG., LamJ., AoY., SandovalF., SurianyS., SofroniewM.V., and VoskuhlR.R. (2011). Neuroprotection mediated through estrogen receptor-α in astrocytes. Proc. Natl. Acad. Sci. U. S. A. 108, 8867–8872.
50.
BentonR.L., RossC.D., and MillerK.E. (2000). Glutamine synthetase activities in spinal white and gray matter 7 days following spinal cord injury in rats. Neurosci. Lett. 291, 1–4.
51.
SribnickE.A., Del ReA.M., RayS.K., WoodwardJ.J., and BanikN.L. (2009). Estrogen attenuates glutamate-induced cell death by inhibiting Ca2+ influx through L-type voltage-gated Ca2+ channels. Brain Res. 1276, 159–170.
52.
SantagatiS., MelcangiR.C., CelottiF., MartiniL., and MaggiA. (1994). Estrogen receptor is expressed in different types of glial cells in culture. J. Neurochem. 63, 2058–2064.
53.
ChiO.Z., BarsoumS., WenY., LiuX., and WeissH.R. (2004). 17beta-estradiol prevents blood-brain barrier disruption induced by VEGF. Horm. Metab. Res. 36, 272–276.
54.
SaddickS.Y. (2014). Ovarian surface epithelium receptors during pregnancy and estrus cycle of rats with emphasis on steroids and gonadotropin fluctuation. Saudi J. Biol. Sci. 21, 232–237.
55.
KuiperG.G., CarlssonB., GrandienK., EnmarkE., HäggbladJ., NilssonS., and GustafssonJ.A. (1997). Comparison of the ligand binding specificity and transcript tissue distribution of estrogen receptors alpha and beta. Endocrinology, 138, 863–870.
KachadrokaS., HallA.M., NiedzielkoT.L., ChongthammakunS., and FloydC.L. (2010). Effect of endogenous androgens on 17β-estradiol-mediated protection after spinal cord injury in male rats. J. Neurotrauma, 27, 611–626.
58.
OzsoyO., OzsoyU., SteinG., SemlerO., SkourasE., SchempfG., WellmannK., WirthF., AngelovaS., AnkerneJ., AshrafiM., SchönauE., Papamitsou-SidoropolouT., JaminetP., SarikciogluL., IrintchevA., DunlopS.A., and AngelovD.N. (2012). Functional deficits and morphological changes in the neurogenic bladder match the severity of spinal cord compression. Restor. Neurol. Neurosci. 30, 363–381.
