Hormonal Intervention Protects Axon-myelin to Promote Functional Recovery in SCI

严重脊髓损伤(Sci)是一种复杂的、使人衰弱的疾病，会导致终生的神经功能障碍。 赤字。除了神经功能障碍外，脊髓损伤患者还会出现神经源性肌肉丧失，原因是 一动不动。改善神经功能缺陷和防止骨骼肌丧失与 脊髓损伤后功能恢复情况。神经元损伤与骨骼肌损伤的分子机制 脊髓损伤造成的损失，至今仍不完全清楚。我们的实验室是最早证明类固醇的实验室之一。 雌激素(E2)对实验性脊髓损伤大鼠的神经保护作用 对神经创伤患者的评估。小剂量(10μg/kg E2)对脊髓损伤有一定的保护作用， 但人类使用的剂量仍然是非生理性的，因此对临床使用构成了一个安全问题。 智能药物输送技术的出现，如纳米颗粒，可能会提高药物安全性 并提高了疗效。因此，这项建议的目标是检查新的快速和缓慢释放的效果 载E2纳米粒(NP)对大鼠脊髓挫伤模型神经元功能障碍和骨骼肌丢失的影响。 由于脊髓运动神经元受损可能导致肌肉丢失，局部注射E2可能 逆转去神经和促进部分去神经肌肉纤维中的神经发芽。初步研究 建议单次给药速释(FNP-E_2)和缓释(SNP-E_2)制剂 减轻炎性细胞因子/趋化因子、胶质增生症、胶质瘢痕形成和神经源性。 肌肉萎缩。局部递送E2促进小胶质细胞和星形胶质细胞分化为抗- 炎性小胶质细胞/星形胶质细胞抑制炎症、轴突损伤和神经元丢失。初步 研究还表明，NP介导的E2凝胶贴片疗法减少了侮辱诱导的肌环 成肌细胞中Fing1(MuRF1)和肌肉萎缩F-box(MAFbx)蛋白的表达 至中度脊髓损伤(40g/cm损伤)。然而，NP-E2凝胶贴片疗法是否改变了神经元损伤 严重脊髓损伤(60g/cm损伤)的骨骼肌丢失尚不清楚。因此，使用一种新的组合FNP- E_2和SNP-E_2可抑制FNP-E_2的急性炎症反应，调节炎症反应。 此后，SNP-E2做出了回应。我们假设联合FNP-E2和SNP-E2的焦点递送将 最大限度地降低血浆雌二醇水平，增加局部脊髓浓度，从而减少急性和亚急性 炎症促进严重脊髓损伤神经原性肌肉丢失的恢复。为了检验这一假设，有三个 提出了具体的目标：(目标1)确定FNP-E2和SNP-E2联合凝胶贴片的递送 治疗并评价其在大鼠严重脊髓损伤模型中的动力学、生物分布、毒性和效果；(目标2) 研究FNP-E_2和SNP-E_2联合治疗对神经元损伤、胶质瘢痕形成和 严重脊髓损伤患者的膀胱/运动功能；以及(目标3)研究FNP-E_2和SNP-E联合应用的效果。 雌二醇治疗对严重脊髓损伤患者骨骼肌丢失、神经炎症和功能结果的影响。总体而言， 在严重脊髓损伤模型中提出的联合策略可能为雌激素的作用机制提供深入的认识。 退伍军人在严重脊髓损伤中的神经保护和神经源性肌肉丢失的预防。完成 应该提供足够的证据来支持将E2转化为临床试验， 为退伍军人和普通民众提供安全有效的治疗的最终目标 来自SCI的。

Severe spinal cord injury (SCI) is a complex, debilitating condition leading to permanent life-long neurological deficits. In addition to neurological dysfunction, individuals with SCI experience neurogenic muscle loss due to immobility. Amelioration of neurological deficits and prevention of skeletal muscle loss are intricately related to recovery of function following SCI. Molecular mechanisms causing neuronal impairment and skeletal muscle loss resulting from SCI, remain incompletely understood. Our laboratory is among the first to demonstrate steroid hormone estrogen (E2) driven neuroprotection in experimental SCI in rats, suggesting E2 warrants clinical evaluation in individuals with neurotrauma. The beneficial effect in SCI was found at a low dose of 10μg/kg E2, but the dose remains at a non-physiologic for human use, and thereby poses a safety concern for clinical use. The emergence of smart drug delivery techniques, such as nanoparticles, may allow for increased drug safety and improved efficacy. Thus, the goal of this proposal is to examine the effects of novel fast and slow release E2-loaded nanoparticles (NP) on neuronal dysfunction and skeletal muscle loss in a rat contusion model of SCI. Since muscle loss may occur as a result of damage to motoneurons in the spinal cord, focal delivery of E2 may reverse denervation and promote nerve sprouting in partially denervated muscle fibers. Preliminary studies suggest that a single administration of a combined fast-release (FNP-E2) and slow-release (SNP-E2) formulation to the contused spinal cord attenuates inflammatory cytokines/chemokines, gliosis, glial scarring, and neurogenic muscle loss. The focal delivery of E2 promotes microglial and astroglial differentiation to subpopulations of anti- inflammatory microglia/astrocytes which inhibit inflammation, axonal damage, and neuronal loss. Preliminary studies also suggest that NP-mediated delivery of E2 gel patch therapy reduces insult-induced muscle RING finger 1 (MuRF1) and muscle atrophy F-box (MAFbx) proteins in vitro in myoblast cells and in vivo following mild to moderate SCI (40g/cm injury) in rats. However, whether NP-E2 gel patch therapy alters neuronal impairment and skeletal muscle loss in severe SCI (60g/cm injury) remains unknown. Thus, using a novel combined FNP- E2 and SNP-E2, may allow for suppression of acute inflammation by FNP-E2 and modulation of the inflammatory response by SNP-E2 thereafter. We hypothesize that focal delivery of combined FNP-E2 and SNP-E2 will minimize plasma E2 levels and increase local spinal cord concentrations - thereby reducing acute and subacute inflammation to promote recovery from neurogenic muscle loss in severe SCI. To test the hypothesis, three specific aims are proposed: (Aim 1) Determine the delivery of a combined FNP-E2 and SNP-E2 gel patch therapy and evaluate its kinetics, bio-distribution, toxicity, and effects in severe SCI model in rats; (Aim 2) Investigate the effects of a combined FNP-E2 and SNP-E2 therapy on neuronal impairment, glial scarring, and bladder/locomotor function in severe SCI; and (Aim 3) Examine the effects of a combined FNP-E2 and SNP- E2 therapy on skeletal muscle loss, neuroinflammation, and functional outcomes in severe SCI. Overall, the proposed combination strategy in a severe SCI model may provide insights into the mechanisms of estrogenic- driven neuroprotection and prevention of neurogenic muscle loss in severe SCI in combat veterans. Completion of this project should provide sufficient evidence to support the translation of E2 into clinical trials, with the ultimate goal of providing a safe and effective therapy to treat both veterans and the general population suffering from SCI.