Enhanced Mitochondrial Viability via Engineered Hyrdogels for Intrathecal Spinal Cord Delivery

项目总结/摘要 线粒体功能障碍是脊髓创伤后神经病理学后遗症的关键 损伤（SCI）。在该初始时间窗期间，存在线粒体的显著损失， 炎症/氧化环境，使病理生理学永久化。据推测， 为了挽救SCI后发生的细胞损伤，必须替换受损的线粒体，同时还 改变有害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-肉毒碱（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）引起的氧化应激 （NACA）脊髓损伤后的结果增加，但有限的长期功能性神经保护。我们还 报道了使用脊髓内注射线粒体的急性线粒体移植（MitoTxp）， 分离自大鼠比目鱼肌的P25在SCI后48小时显著地保持了生物能量功能。然而，在这方面， 这是零星的成功，由于挑战的积累线粒体的网站， 损伤并在细胞摄取之前维持它们的活力。在目前的建议中，我们将制定一个 用于活线粒体的局部递送的热胶凝、可侵蚀的水凝胶系统，以测试 MitoTxp和药物干预（ALC和/或NACA）的组合的神经保护功效 挫伤性脊髓损伤可注射水凝胶的使用将允许局部环境的发展， 可以通过优化水凝胶生态位来帮助维持线粒体健康。我们将确定 1)分离的线粒体在聚合物中长时间保持活力的最佳成分 水凝胶，2）外源性线粒体是否通过微创鞘内途径移植， 与脊柱内途径相比，保持生物能量学的完整性，以及3）急性或 延迟的MitoTxp与ALC和/或NACA组合对生物能量学、氧化应激和功能的影响 SCI后神经保护

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.