Somatostatin gene delivery to enhance long-term functional recovery from TBI

在军事人员中，创伤性脑损伤(TBI)的发生率高得不成比例。即使是温和的 创伤性脑损伤可能会产生持续的不良神经生物学影响，在最初的损伤后很长一段时间内仍会继续发展。 癫痫、痉挛、认知和情感障碍、睡眠问题和内分泌疾病(糖尿病)是 流行的，使人衰弱的，难以治疗的。有效的长期康复将需要变革性的 针对导致延迟症状出现的大脑过程的治疗方法。 脑外伤后这些问题的延迟演变为预防和改善长期问题提供了机会 结果。我们开发的一种基因传递技术产生了持续的基因过度表达 神经肽生长抑素(SST)在离散的大脑区域。用腺相关基因载体进行颅内基因传递 与我们的SST载体类似的病毒(AAV)载体在几个大脑的临床试验中被证明是安全和有效的 疾病。在中枢神经系统中，SST参与突触抑制、炎症、认知、 情绪功能、镇痛和细胞保护，它可能通过多种机制提供积极的 针对延迟的TBI影响的好处。我们的SST基因传递到海马体的电阻止 在已建立的癫痫模型中测试的大鼠中，70%的大鼠发生了诱发癫痫发作。下一步是 将这种方法转化为临床有用的应用是在更高级的大脑动物模型中进行测试 受伤。同时，确定这种方法的安全性对于进一步的临床前研究将是至关重要的。 发展。因此，有效性和安全性构成了这个小项目的两个具体目标，旨在作为一个 翻译进步的基础。以测试疗效是否延伸到癫痫发作的延迟发展 在脑损伤后，我们将结合一种具有良好特征的闭合性脑损伤大鼠模型和点燃癫痫模型 首次观察到了哪种疗效。麻醉年轻成年雄性大鼠将给予控制性脑损伤10只 在接受海马区SST或对照基因转移载体脑内注射的前几天，以及 在一次手术中永久植入用于电刺激的电极。一周后，一堆火柴 启动的程序将包括每天两次的定时刺激，使用阈值以下的强度 癫痫的产生。配对脑电图仪(EEG)和刺激过程中获得的视频记录 癫痫发作将作为严重程度和持续时间的重复衡量标准被盲打为离线分数。逐渐超过了 在几天到几周之后，轻度癫痫开始发作，并逐渐加重，直到达到完全 点燃状态，在这种状态下，刺激持续地在未治疗的大鼠中引起最强烈的癫痫发作。 海马区SST基因导入的治疗效果将反映在癫痫严重程度的降低或 持续时间，癫痫严重程度的延迟进展，或最大癫痫严重程度的降低 始终如一地被唤醒。检测脑损伤、基因转移和点燃对记忆操作敏感性的影响 对于海马损伤，大鼠在连续的Y形迷宫中探索交替的手臂是一种自然的倾向 试验将在整个研究过程中反复进行测试。认知表现将从多个方面进行评估 挑战对学习和记忆能力敏感的任务。自然运动功能(活动、养育、梳理)， 情感状态(焦虑)和昼夜生理(睡眠)将从连续的家庭笼子中进行评估 红外线视频。治疗安全性将从全面的行为评估中进行评估，但也要通过 脑部病理的综合组织学分析作为载体治疗的功能。除了……之外 病理标记物，我们将评估基因转移对点燃脑损伤大鼠空间定位的影响 SST受体蛋白的模式。我们建议减少癫痫发作，改善渐进性 脑外伤后认知和运动功能障碍，将涉及多个功效机制 大脑特定亚区的受体亚型。这个可行而创新的小项目开启了新的 改善退伍军人康复的途径，这些退伍军人在脑外伤后面临数十年的衰弱后果。

The incidence of traumatic brain injury (TBI) is disproportionately high among military personnel. Even mild TBI can have persistent adverse neurobiological effects that can continue to evolve long after the initial injury. Seizures, spasticity, cognitive and affective disorders, sleep problems, and endocrine diseases (diabetes) are prevalent, debilitating, and difficult to treat. Effective long-term rehabilitation will require transformative therapeutic approaches that address the brain processes responsible for the emergence of delayed symptoms. The delayed evolution of these problems post-TBI offers opportunities for prevention and improved long-term outcome. A gene delivery technique we developed produces sustained over-expression of the gene for neuropeptide somatostatin (SST) in discrete brain regions. Intracranial gene delivery using adeno-associated viral (AAV) vectors similar to our SST vector is proving safe and effective in clinical trials for several brain diseases. In the central nervous system SST participates in synaptic inhibition, inflammation, cognition, emotional function, analgesia, and cytoprotection, multiple mechanisms by which it might provide positive benefits against delayed TBI effects. Our SST gene delivery to the hippocampus prevented electrically induced seizures from developing in 70% of rats tested in an established epilepsy model. The next step in translating this approach to clinically useful applications is to test it in more advanced animal models of brain injury. At the same time, determining the safety of this method will be essential for further preclinical development. Efficacy and safety thus comprise 2 specific aims of this Small Project intended to serve as a foundation for translational progress. To test whether efficacy extends to the delayed development of seizures after TBI, we will combine a well-characterized rat model for closed-head TBI with the kindling seizure model in which efficacy was first observed. Anesthetized young adult male rats will be given a controlled brain injury 10 days before receiving intracranial infusion of SST or control gene transfer vectors in hippocampus, and permanently implanted electrodes for electrical stimulation, during a single surgery. A week later a kindling procedure will be initiated composed of timed stimulation twice per day, using intensities sub-threshold for seizure generation. Paired electroencephalograph (EEG) and video recordings obtained during stimulated seizures will be scored blind offline as duplicate measures of severity and duration. Gradually over the following days to weeks mild seizures start and become progressively more severe until reaching a fully kindled state where the stimulation consistently elicits maximally intense seizures in untreated rats. Therapeutic efficacy of hippocampal SST gene delivery will be reflected in reduced seizure severity or duration, delayed progression of seizure severity, or a reduction in the maximal seizure severity that can be consistently evoked. To examine effects of TBI, gene transfer, and kindling on memory performance sensitive to hippocampal injury, a natural tendency of rats to explore alternating arms of a Y-shaped maze on successive trials will be tested repeatedly throughout the study. Cognitive performance will be evaluated on multiple challenge tasks sensitive to learning and memory ability. Natural motor function (activity, rearing, grooming), affective states (anxiety), and circadian physiology (sleep) will be assessed from continuous home cage infrared video. Therapeutic safety will be evaluated from comprehensive behavioral assessments, but also by comprehensive histological analysis of brain pathology as a function of vector treatment. In addition to markers for pathology, we will evaluate the effects of gene transfer in kindled TBI rats on spatial localization patterns of SST receptor proteins. We propose that seizure reduction, and amelioration of progressive cognitive and motor dysfunction post-TBI, will involve multiple efficacy mechanisms that engage several receptor subtypes in specific subregions of the brain. This feasible and innovative Small Project opens new avenues for improving the rehabilitation of Veterans facing decades of debilitating consequences after TBI.