Enhancing Plasticity in Damaged Spinal Cord to Repair Transmission and Function

增强受损脊髓的可塑性以修复传输和功能

• 批准号: 8668722
• 负责人: Victor L Arvanian
• 金额: --
• 依托单位: NORTHPORT VA MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-04-01 至 2017-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8668722
• 关键词: Accounting; Action Potentials; Acute; Address; Adult; Afghanistan; Anatomy; Animal Model; Animals; Award; Axon; Behavior; Biological Preservation; Cells; Chest; Chondroitin ABC Lyase; Chondroitin Sulfate Proteoglycan; Chronic; Cicatrix; Clinical; Clinical Trials; Combined Modality Therapy; Conflict (Psychology); Confocal Microscopy; Contusions; Demyelinations; Digestion; Electron Microscopy; Electrophysiology (science); Engineering; Enzymes; Exhibits; Experimental Models; Exposure to; FDA approved; Fiber; Fibroblasts; Freedom; Funding; Gene Delivery; Genes; Goals; Growth; Herpesvirus 1; Hindlimb; Home environment; Immunochemistry; Individual; Injury; Interneurons; Intramuscular; Intrathecal Injections; Ion Channel; Iraq; Lateral; Left; Lesion; Locomotor Recovery; Magnetism; Mediating; Mental disorders; Methods; Modeling; Molecular; Motor; Motor Neurons; Muscle; N-Methyl-D-Aspartate Receptors; N-Methylaspartate; NR2D NMDA receptor; NTF3 gene; Natural regeneration; Neurons; Pathway interactions; Physiological; Physiology; Procedures; Property; Ranvier' s Nodes; Rattus; Recombinants; Recovery; Recovery of Function; Research; Scientist; Sensory; Side; Site; Soldier; Spinal; Spinal Cord; Spinal Cord Lesions; Spinal Injections; Spinal Injuries; Spinal cord damage; Spinal cord injury; Synapses; Synaptic plasticity; Therapeutic; Thoracic spinal cord structure; Time; Tissues; Transgenes; Translating; Treatment Efficacy; United States; Viral Vector; War; Work; adeno-associated viral vector; axon growth; base; behavior test; coping; disability; dorsal column; effective therapy; gene therapy; improved; in vivo; inhibitor/antagonist; motor function improvement; motor function recovery; multidisciplinary; nervous system disorder; neurotrophic factor; news; novel; operation; public health relevance; receptor function; remyelination; repaired; research study; response; spinal cord and brain injury; spinal tract; spine bone structure; therapy design; transmission process; white matter

DESCRIPTION (provided by applicant): Many soldiers return home with contusive spinal cord injuries (SCI), mostly due to the powerful explosives used in the improvised bombs that rattle U.S. troops inside heavily armored vehicles. In fact, "One in Six Wounded in Afghanistan War Have Spinal Cord Injuries" (The Spinal Post, Nov.11, 2009"). Currently, there is no cure and consequently studies using animal models of SCI are imperative. Results of recent studies, including our own, revealed that there are at least three major factors known to limit functional recovery from incomplete SCI in adults: (1) the presence of axonal growth/regeneration inhibitors associated with the glial scar, (2) the lack of neurotrophin support, and (3) the decreased excitability and plasticity in pre- existing pathways to neurons in damaged spinal cord. In attempts to improve synaptic connectivity in the damaged spinal cord and examine if this will facilitate recovery of motor function after SCI, we have recently utilized a model of unilateral hemisection (HX) of the spinal cord in adult rats. This is convenient experimental model because one side of the cord is lesioned and other remains intact. Using this HX model we have recently developed (through studies funded by our initial Merit Award; 2008-2012), a novel additive treatment designed to neutralize axonal growth/ regeneration inhibitors, deliver neurotrophins and enhance plasticity in damaged spinal cord. We found that this combination treatment (in contrast to treatment with any single component) can re-establish novel synaptic connections around a lesion in chronically hemisected spinal cord. These physiological findings were supported by the observation of increased regeneration and branching of axons near the injury and better functional recovery. Components of this combination treatment are: (i) degradation of scar-associated inhibitory molecules (CSPGs) with the enzyme chondroitinase-ABC (ChABC), (ii) delivery of neurotrophin NT-3 (administered via engineered fibroblasts) and increased function of NMDA receptors in interneurons and motoneurons (using HSV1 viral vector-mediated expression of NMDA receptor NR2D regulatory subunits). The goal of the current proposal is to translate these principles into a clinically amenable application. The proposed research will be a continuation of our previous work, extended to a more realistic contusive SCI model, with refinement of methods for NT-3 delivery and enhanced spinal cord excitability that are FDA- approved or under clinical trials. This novel triple combination approach will combine Ch-ABC treatment with (i) AAV-mediated transgene delivery of NT-3 (AAV-NT3; intraspinal and intrathecal injections; AAV-mediated gene delivery has been found to be safe in multiple clinical trials) and (ii) repetitive electro-magnetic stimulation applied over intact spinal vertebrae (FDA-approved and widely used for treatment of neurological and psychiatric disorders). Due to increasing numbers of individuals with chronic SCI, we will utilize both acute and chronic mid-thoracic contusion SCI models in adult rats. To evaluate the efficacy of these treatments, we will collaborate with leading scientists in the field and conduct a multidisciplinary examination, including in vivo physiology, anatomy, immunochemistry, electron microscopy and behavior. Using these methods we will study the additive or synergistic effects of the triple therapeutic treatment on (1) strengthening synaptic connections through the injury epicenter to lumbar motoneurons, and then to hindlimb muscles (electrophysiology); (2) anatomical plasticity of fibers accounting for the persistence of the synaptic response after exposure to this novel treatment (anatomical tracing and confocal microscopy); (3) cellular and molecular mechanisms underlying the beneficial effects of the combination treatment (electron microscopy and immunochemisctry to study axon remyelination and distribution of ion channels); and (4) recovery of locomotor function in multiple behavioral tests. Preliminary results of on-going experiments show significant improvements of motor function in rats that have received the novel triple treatment compared to controls after thoracic contusive SCI.

描述（由申请人提供）： 许多士兵回家时都患有脊髓挫伤（SCI），这主要是由于简易炸弹中使用的威力强大的炸药使重型装甲车内的美军感到惊慌。事实上，“阿富汗战争中六分之一的伤员患有脊髓损伤”（The Spinal Post，2009 年 11 月 11 日）。目前尚无治愈方法，因此使用 SCI 动物模型进行研究势在必行。最近的研究结果包括我们自己在内的研究表明，至少存在三个已知的主要因素限制成人不完全性 SCI 的功能恢复：(1) 与神经胶质疤痕相关的轴突生长/再生抑制剂的存在，(2)缺乏神经营养蛋白的支持，以及（3）受损脊髓中先前存在的神经元通路的兴奋性和可塑性降低。我们最近在成年大鼠中使用了脊髓单侧半切 (HX) 模型，这是一种方便的实验模型，因为脊髓的一侧受损，而另一侧保持完整（通过我们资助的研究）。获得我们最初的优异奖； 2008-2012），一种新型添加剂治疗，旨在中和轴突生长/再生抑制剂，输送神经营养素并增强受损脊髓的可塑性。我们发现这种联合治疗（与任何单一成分的治疗相反）可以在慢性半切脊髓的病变周围重建新的突触连接。这些生理学发现得到了损伤附近轴突再生和分支增加以及更好的功能恢复的观察结果的支持。该联合治疗的组成部分包括：(i) 用软骨素酶-ABC (ChABC) 降解疤痕相关抑制分子 (CSPG)，(ii) 输送神经营养素 NT-3（通过工程化成纤维细胞施用）和增强 NMDA 功能中间神经元和运动神经元中的受体（使用 HSV1 病毒载体介导的 NMDA 受体 NR2D 调节亚基表达）。 当前提案的目标是将这些原则转化为临床上可行的应用。拟议的研究将是我们之前工作的延续，扩展到更现实的挫伤性 SCI 模型，并改进 FDA 批准或正在进行临床试验的 NT-3 递送方法和增强脊髓兴奋性。这种新颖的三重组合方法将 Ch-ABC 治疗与 (i) AAV 介导的 NT-3 转基因递送结合起来（AAV-NT3；椎管内和鞘内注射；多项临床试验已发现 AAV 介导的基因递送是安全的） (ii) 对完整的脊椎施加重复电磁刺激（经 FDA 批准并广泛用于治疗神经和精神疾病）。由于患有慢性 SCI 的人数不断增加，我们将在成年大鼠中使用急性和慢性胸中部挫伤 SCI 模型。为了评估这些治疗的功效，我们将与该领域的领先科学家合作 并进行多学科检查，包括体内生理学、解剖学、免疫化学、电子显微镜和行为学。使用这些方法，我们将研究三重治疗的累加或协同效应：（1）加强通过损伤中心到腰部运动神经元，然后到后肢肌肉的突触连接（电生理学）； (2) 纤维的解剖学可塑性解释了接受这种新型治疗后突触反应的持续性（解剖追踪和共焦显微镜）； (3) 联合治疗有益效果背后的细胞和分子机制（电子显微镜和免疫化学研究轴突髓鞘再生和离子通道分布）； (4)多项行为测试中运动功能的恢复。正在进行的实验的初步结果显示，与对照组相比，接受新型三联治疗的大鼠在胸部挫伤性 SCI 后运动功能显着改善。