Mechanisms of Vascular Protection after Acute Stroke

描述（由申请人提供）：在美国每年接受治疗的60多万急性缺血性中风患者中，98%的患者没有接受急性治疗。合并血管疾病的患者，如糖尿病和不受控制的高血压，预后更差，在临床前研究中一直代表性不足。长期恢复受到大脑固有的可塑性和损伤后主动重塑的能力的限制。脑血管系统无疑是恢复和治疗策略的关键组成部分，血管保护可能促进更好的功能。促进自然恢复机制，特别是当脑缺血是在预先存在的血管损伤的基础上分层时，作为一种治疗策略有很大的希望。本研究旨在进一步阐明脑缺血后血管保护的机制。本研究的中心假设是脑缺血再灌注后的神经血管保护可以通过优化氧化应激和激活重塑来实现。我们计划通过以下三个具体目标来实现这一目标：目标#1：确定氧化应激和MMP调节对血管紧张素拮抗剂对实验性缺血性卒中结果的有益作用的贡献。目的2：确定急性缺血性卒中后发病前血管损伤对血管紧张素拮抗剂神经血管保护作用的影响程度。目的3：确定坎地沙坦在脑缺血后对血管的最佳保护是否必需再灌注。我们将通过暂时脑缺血的正常、高血压和高血糖大鼠模型，通过遥测、激光多普勒血流仪持续监测血压，降压和药理学MMP和氧化应激调节来实现这些目标。此外，我们将采用MMP酶谱法，并使用ELISA和免疫印迹法定量测量微血管完整性和氧化损伤，并在第3、7和30天进行敏感的神经行为测试。最后，我们将利用脑微血管内皮细胞培养进行研究。在完成5年12个实验后，我们预计氧化应激和MMP活性的变化将有助于血管紧张素阻断在急性中风期间提供的血管保护。我们预计，既往高血压、高血糖、内源性血管保护剂的存在以及与再灌注状态相关的治疗方法和时间对神经血管损伤的最终程度将是重要的。这很重要，因为它将为临床试验提供动力和指导，以改善人类中风患者的预后。

DESCRIPTION (provided by applicant): Of the more than 600,000 acute ischemic strokes treated annually in the United States, 98% of patients receive no acute therapy. Patients with co-morbid vascular diseases, like diabetes and uncontrolled hypertension, have worse outcomes and have historically been underrepresented in preclinical studies. Long-term recovery is limited by the brain's inherent plasticity and ability to actively remodel after injury. The brain vasculature is undoubtedly a key component of recovery and therapeutic strategies that are vascular protective are likely to promote better function. The facilitation of natural recovery mechanisms, especially when cerebral ischemia is layered on preexisting vascular compromise, has great promise as a therapeutic strategy. The objective of this application is to further elucidate the mechanisms involved in vascular protection after cerebral ischemia. The central hypothesis for the proposed research is that neurovascular protection after cerebral ischemia and reperfusion can be achieved by optimization of oxidative stress and activation of remodeling. We plan to achieve this objective through the following three specific aims: Aim #1: Determine the contribution of oxidative stress and MMP modulation to the beneficial effects of angiotensin antagonism on experimental ischemic stroke outcome. Aim #2: Determine the extent to which premorbid vascular damage impacts the neurovascular protective effects of angiotensin antagonism after acute ischemic stroke. Aim #3: Determine whether reperfusion is essential for optimal vascular protection with candesartan after cerebral ischemia We will achieve these aims using normotensive, hypertensive and hyperglycemic rat models of temporary cerebral ischemia, continuous BP monitoring via telemetry, laser Doppler flowmetry, BP lowering and pharmacologic MMP and oxidative stress modulation. In addition, we will employ MMP zymography, and quantitative measures of microvascular integrity and oxidative damage using ELISA and immunoblotting and a sensitive battery of neurobehavioral tests at 3, 7 and 30 days. Lastly, we will use brain microvascular endothelial cell culture studies. At the completion of 12 experiments over 5 years, we expect that changes in oxidative stress and MMP activity will contribute to the vascular protection afforded by angiotensin blockade in the acute stroke period. We expect that the presence of prior hypertension, hyperglycemia, endogenous vascular protectors and the method and timing of treatment in relation to reperfusion status will be important in the ultimate degree of neurovascular damage. This is important because it will provide impetus and guidance for a clinical trial to improve outcome of human stroke patients.