Enhanced Mitochondrial Viability via Engineered Hyrdogels for Intrathecal Spinal Cord Delivery

项目摘要/摘要 线粒体功能障碍是脊髓损伤后神经病理后遗症的关键 损伤(SCI)。在最初的时间窗口内，线粒体有显著的丢失 使病理生理永久化的炎症/氧化环境。据推测， 抢救脊髓损伤后的细胞损伤，必须替换受损的线粒体，同时 改变破坏性的微环境。我们已经证明，保持内源性 线粒体生物能量学与乙酰-L肉碱(ALC)，一种替代线粒体生物燃料，或减少 用N-乙酰半胱氨酸酰胺补充内源性抗氧化剂谷胱甘肽(GSH)的氧化应激 (NACA)对脊髓损伤后的结果是增加，但有限的长期功能性神经保护。我们还有 报道了急性线粒体移植(MitoTxp)采用椎管内注射线粒体 分离的大鼠比目鱼肌在脊髓损伤后48小时显著保留了生物能量功能。然而， 这是零星的成功，因为这两个地点积累线粒体的挑战 损伤并在细胞摄取之前维持其生存能力。在目前的提案中，我们将制定一项 热凝胶，可腐蚀的水凝胶系统，用于局部输送有活力的线粒体以测试 MitoTxp联合药物干预(ALC和/或NACA)的神经保护作用 脊髓挫伤。使用可注射水凝胶将使当地环境得以发展， 可以通过优化水凝胶生态位来帮助维持线粒体的健康。我们将决定 1)分离的线粒体在聚合物中长期存活的最佳成分 水凝胶，2)外源线粒体是否同样通过鞘内微创途径移植 与椎管内途径相比，保持生物能量学的完整性和3)急性或 延迟MitoTxp联合ALC和/或NACA对生物能量学、氧化应激和功能的影响 脊髓损伤后的神经保护。

Project Summary/Abstract Mitochondrial dysfunction is pivotal to the neuropathological sequelae following traumatic spinal cord injury (SCI). During this initial time window, there is a significant loss of mitochondria with an inflammatory/oxidative environment that perpetuates the pathophysiology. It is hypothesized that to rescue the cellular damage occurring following SCI, one must replace damaged mitochondria, while also changing the damaging microenvironment. We have documented that maintaining endogenous mitochondrial bioenergetics with acetyl-l-carnitine (ALC), an alternative mitochondrial biofuel, or reducing oxidative stress by replenishing endogenous antioxidant, glutathione (GSH) with N-acetylcysteine amide (NACA) after SCI results in increased, but limited long-term functional neuroprotection. We have also reported that acute mitochondrial transplantation (MitoTxp) using intraspinal injections of mitochondria isolated from rat soleus muscle significantly preserved bioenergetic function 48hr post-SCI. However, this was sporadically successful due to the challenges of both accumulating mitochondria at the site of injury and maintaining their viability prior to cellular uptake. In the current proposal, we will develop a thermo-gelling, erodible hydrogel system for the localized delivery of viable mitochondria to test the neuroprotective efficacy of combined MitoTxp and pharmaceutical interventions (ALC and/or NACA) after contusion SCI. The use of an injectable hydrogel will permit the development of a local environment which can aide in maintaining mitochondrial health through optimization of the hydrogel niche. We will determine 1) optimum constituents for isolated mitochondria to remain viable for extended periods in polymeric hydrogels, 2) whether exogenous mitochondria transplanted via less invasive intrathecal route equally preserve integrity of bioenergetics compared to intraspinal route and 3) consequences of acute or delayed MitoTxp in combination with ALC and/or NACA on bioenergetics, oxidative stress, and functional neuroprotection after SCI.