Release Chondroitinase Systems for Spinal Cord Injury

描述（由申请人提供）：脊髓损伤（SCI）对中枢神经系统的细胞和组织造成创伤，并导致个体严重和衰弱。脊髓损伤后，受损神经元的有限再生导致永久性残疾，其特征是一些感觉丧失、瘫痪和自主神经功能障碍。神经元不能再生的一个原因是它们不能穿过脊髓损伤后形成的胶质瘢痕。这种神经胶质瘢痕含有细胞外基质分子，包括硫酸软骨素蛋白聚糖（CSPG）。体外研究表明，神经元不能在CSPG包被的表面上延伸突起，而体内数据将再生失败与CSPG表达区域相关联。用细菌软骨素酶（Chase）（一种使CSPG碳水化合物链断裂的酶）处理，在体外和体内均降低CSPG抑制。Chase最近被用于治疗啮齿动物模型中的脊髓病变，从而增强了功能恢复。在开发基于Chase的SCI治疗中存在几个障碍，包括向中枢神经系统递送大蛋白质和使用在体温下在溶液中具有短半衰期的酶。本研究的目的是开发Chase疗法的缓释（SR）制剂，其可以局部递送至损伤部位，并证明其在大鼠脊髓中消化CSPG的有效性。为了实现这些目标，将克隆、表达和纯化Chase酶的库。然后将在几种现有的持续释放制剂中对这些酶进行体外测试。然后将这些持续释放Chase制剂置于大鼠脊髓的硬膜下空间中以评估其在体内消化CSPG的能力。这些研究将为在脊髓损伤动物模型中检查软骨素酶缓释制剂的治疗效果的II期研究提供依据。

DESCRIPTION (provided by applicant): Spinal cord injury (SCI) inflicts trauma to the cells and tissues of the central nervous system and causes a severe and debilitating condition in the individual. Following SCI, limited regeneration of injured neurons results in permanent disability characterized by some loss of sensation, paralysis and autonomic dysfunction. One reason that neurons fail to regenerate is their inability to traverse the glial scar that develops following SCI. This glial scar contains extra cellular matrix molecules including chondroitin sulfate proteoglycans (CSPGs). In vitro studies show that neurons fail to extend processes over CSPG coated surfaces, while in vivo data correlate failure of regeneration with areas of CSPG expression. Treatment with bacterial chondroitinase (Chase), an enzyme that digests CSPG arbohydrate chains, decreases the CSPG inhibition, both in vitro and in vivo. Chase was recently used to treat spinal cord lesions in a rodent model, resulting in enhanced functional recovery. Several obstacles exist in the development of a Chase-based SCI therapy, including the delivery of a large protein to the central nervous system and the use of an enzyme with a short half-life in solution at body temperature. The aim of this study is to develop a sustained release (SR) formulation of a Chase therapy that can be delivered locally to the site of injury and demonstrate its effectiveness at digesting CSPGs in the rat spinal cord. To accomplish these goals are a repertoire of Chase enzymes will be cloned, expressed and purified. These enzymes will then be tested in vitro in several existing sustained release formulations. These sustained release Chase formulations will then be place in the sub-dural space of rat spinal cords to assess their ability to digest CSPGs in vivo. These studies will provide justification for a Phase II study examining the therapeutic effects of sustained release formulation of chondroitinase in an animal model of spinal cord injury.