Ischemic Spasticity: Modulation by GAD65 Gene Delivery

描述（由申请人提供）：使用大鼠脊髓缺血模型，我们已经表明，特定时期的短暂性脊髓缺血导致腰骶节中小型抑制性神经元选择性变性，并发展为显著和永久性的痉挛和僵硬。在胸腹主动脉瘤修复或创伤性脊髓损伤的患者中也有类似的痉挛和僵硬的发展。虽然痉挛和僵硬的临床症状可以通过巴氯芬（GABA B受体激动剂）或替沙定（alpha2激动剂）等药物的全身或脊柱治疗有效控制，但慢性鞘内插管的显著副作用和并发症要求开发新的更有效的治疗方法。近年来，大量的注意力集中在腺病毒或慢病毒载体的潜在用途上，目的是上调大脑或脊髓特定区域的治疗基因。这些初步研究清楚地表明，在纹状体内注射编码GAD65基因的腺相关病毒可有效抑制帕金森运动障碍，并与局部GABA释放增加有关。在本研究中，我们将利用已建立的大鼠缺血性痉挛和僵直模型，研究脊髓慢病毒介导的GAD65基因递送可能的治疗潜力，以产生局部GABA合成上调并改善痉挛和僵直。GAD65基因的局部上调对发生痉挛和僵直的动物的影响将通过i)直接脊髓实质慢病毒递送或脊髓移植转基因产生GABA的大鼠神经元前体，ii)痉挛和僵直的电生理/功能指标，iii)相应的脊髓实质来完成和评估！GABA释放，iv)转基因表达的组织学分析。从实践的角度来看，这些研究将系统地解决我们认为具有基础和临床重要性的问题。因此，选择性地增加先前缺血，GABA神经元枯竭节段的GABA合成的能力，可能在开发新的治疗模式以治疗缺血性或创伤性脊髓损伤后患者的慢性痉挛和僵硬方面具有特别重要的意义。

DESCRIPTION (provided by applicant): Using a rat spinal ischemia model, we have shown that specific periods of transient spinal ischemia lead to a selective degeneration of small and medium-sized inhibitory neurons in lumbosacral segments and the development of prominent and permanent spasticity and rigidity. Similar development of spasticity and rigidity in patients undergoing thoracoabdominal aortic aneurysm repair or after traumatic spinal injury had been described. While the clinical signs of spasticity and rigidity can be effectively controlled by systemic or spinal treatment with several pharmacological agents including baclofen (GABA B receptor agonist) or tizadinine (alpha2 agonist), significant side effects and complications associated with chronic intrathecal cannulations calls for the development of new and more effective therapies. In recent years, significant attention has been focused on a potential use of adeno-or lenti-viral vectors with the goal to upregulate therapeutic genes in specific areas of the brain or spinal cord. These initial studies clearly show that intrastriatal injections of adeno-associated virus encoding GAD65 gene is effective in suppressing parkinsonian dyskinesias and is associated with an increase in local GABA release. In the present studies, using an established rat model of ischemic spasticity and rigidity, we will examine a possible therapeutic potential of spinal lentivirus-mediated GAD65 gene delivery in order to produce local upregulation of GABA synthesis and ameliorate spasticity and rigidity. The effect of local GAD65 gene upregulation in animals with developed spasticity and rigidity will be accomplished and assessed by i) direct spinal parenchymal lentivirus delivery or spinal grafting of rat neuronal precursors genetically modified to produce GABA, ii) electrophysiological/functional indices of spasticity and rigidity, iii) corresponding spinal parenchyma! GABA release, and, iv) histological analysis of transgene expression. From a practical standpoint, these studies will systematically address issues which we believe have both basic and clinical importance. Thus the ability to selectively increase GABA synthesis in previously ischemic, GABA neuron-depleted segments, may prove to be of particular significance in developing novel therapeutic modalities for managing chronic spasticity and rigidity in patients after ischemic or traumatic spinal injury.