Spreading Depolarizations and Neuronal Vulnerability

项目总结 该项目探讨了导致急性脑损伤进展的基本机制， 包括中风和创伤。我们的长期目标是开发可在后期应用的干预措施 时间点，最终将可转化为临床研究，以提高存活率和质量 幸存者的生活。该项目的重点是扩散去极化(SD)现象，它具有 最近被认为是急性脑损伤进展延迟的关键因素。近期临床 现在的记录表明，重复的SD波会导致中风和中风的损害进展很多天 创伤病人。现在的挑战是了解如何阻止破坏性的SD，或者如何 支持受伤的脑组织在SD的有害影响下存活。因此，该项目解决了关键问题 在将SD与伤害联系起来的机制方面存在知识空白。我们将使用脑片和动物模型来 确定可持续发展破坏性影响的基本机制，以及支持的方法 受损的组织从反复的SD发作中恢复。我们的中心假设是 选择性地缩短单个SD事件的持续时间将减少间歇性谷氨酸和钙介导的 每个SD事件间歇性发生的神经元损伤。此外，保持传播的 通过梗死区周围组织的十二烷基硫酸钠将维持SD对脑恢复所需的有益作用。我们会 检测限制谷氨酸瞬变和/或激活NMDA型谷氨酸受体是否具有特异性 在SD的晚期将支持SD后神经元的恢复。《特定目标1》检验了假设 病理生理谷氨酸脉冲严格限于SD，并在新陈代谢中延伸 由于突触前释放和星形胶质细胞代谢调节中断而导致的受损组织 受损的切片。特定目标2验证了以下假设：以SD的脆弱阶段为目标将 促进新陈代谢受损组织的神经元恢复。我们将评估神经细胞的钙负荷， 以及用于确定改善钙负荷恢复的方法的药物干预， 而不损害有益的机制。特定目标3在IN中对这些机制进行了关键测试 活体设置。在每个目标中将使用成像和电生理相结合的方法， 在脑片中表征细胞机制(目标1和2)，然后在体内测试(目标3)。从基因上讲- 谷氨酸和钙的编码传感器将补充其他单神经元电生理和 成像方法。将对药理学方法进行测试，以确定机制和 减少SD对代谢受损组织的有害影响的干预措施。成功 完成这些目标应该确定将SD与细胞损伤联系起来的基本机制 损害的组织，并为合理的方法提供基础，可以为 在一系列急性脑损伤后的关键日子里应用干预措施。

PROJECT SUMMARY This project addresses fundamental mechanisms that contribute to the progression of acute brain injuries, including stroke and trauma. Our long-term goal is to develop interventions that can be applied at late time points, and which ultimately will be translatable to clinical studies to improve survival, and quality of life of survivors. The project focuses on the phenomenon of Spreading Depolarization (SD), which has recently emerged as a key contributor to the delayed progression of acute brain injuries. Recent clinical recordings now imply that repetitive SD waves cause progression of damage for many days in stroke and trauma patients. The challenge now is to understand how to block damaging SDs, or alternatively how to support injured brain tissue to survive deleterious effects of SD. This project therefore addresses key gaps in knowledge about mechanisms linking SD to injury. We will use brain slices and animal models to identify fundamental mechanisms that underlie damaging effects of SD, and approaches to support compromised tissues to recover from repeated SD episodes. Our central hypothesis is that agents that selectively reduce the duration of individual SD events will reduce episodic glutamate and Ca2+-mediated neuronal injury that occurs episodically with each SD event. Furthermore, preserving the propagation of SDs through peri-infarct tissues will maintain beneficial effects of SD required for brain recovery. We will test whether limiting glutamate transients and/or activation of NMDA-type glutamate receptors specifically during the late phase of SD will support neuronal recovery after SD. Specific Aim 1 tests the hypothesis that pathophysiological glutamate pulses are strictly limited to SD, and extended in metabolic compromised tissues, due to presynaptic release and disruption of astrocytic regulation in metabolically compromised slices. Specific Aim 2 tests the hypothesis that targeting the vulnerable phase of SD will promote neuronal recovery metabolically compromised tissues. Neuronal Ca2+ loading will be evaluated, and pharmacological interventions used to identify approaches to improve recovery of Ca2+ loading, without impairing beneficial mechanisms. Specific Aim 3 makes key tests of these mechanisms in an in vivo setting. Combined imaging and electrophysiological methods will be used throughout each aim, with cellular mechanisms characterized in brain slices (Aims 1&2) and then tested in vivo (Aim 3). Genetically- encoded sensors for glutamate and calcium will complement other single-neuron electrophysiological and imaging approaches. Pharmacological approaches will be will be tested to identify mechanisms and interventions that reduce deleterious effects of SD in metabolically compromised tissues. Successful completion of these aims should identify fundamental mechanisms linking SD to cellular injury in compromised tissues, and provide the basis for rational approaches that can be developed for interventions applied in the critical days following a range of acute brain injuries.