Role of Microthrombi and Inflammation in Delayed Deficits after SAH

微血栓和炎症在 SAH 后迟发性缺陷中的作用

• 批准号: 10304938
• 负责人: Devin William McBride
• 金额: $ 55.93万
• 依托单位: UNIVERSITY OF TEXAS HLTH SCI CTR HOUSTON
• 依托单位国家: 美国
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-12-01 至 2025-11-30
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10304938
• 关键词: Address; Amidines; Aneurysmal Subarachnoid Hemorrhages; Antibodies; Antiplatelet Drugs; Attenuated; Autopsy; Behavioral; Blood Platelets; Brain; Cell Death; Cells; Cerebral Ischemia; Cerebrum; Chromatin; Clinical; Clinical Research; Clinical Trials; Data; Deoxyribonuclease I; Deposition; Development; Etiology; Flow Cytometry; Goals; Gold; Human; Image; Immune; Incidence; Infarction; Inflammation; Inflammatory Response; Injury; Internet; Ischemia; Laser Speckle Imaging; Link; Magnetic Resonance Imaging; Mediating; Memory; Morbidity - disease rate; Mus; Neurologic; Neurologic Deficit; Outcome; Patient-Focused Outcomes; Patients; Perforation; Performance; Perfusion; Peripheral; Platelet Activation; Platelet Inhibitors; Platelet aggregation; Play; Reporting; Research; Role; Subarachnoid Hemorrhage; Testing; Thrombosis; Tumor-infiltrating immune cells; Vasospasm; brain tissue; cerebral microvasculature; cytokine; design; experimental study; extracellular; functional outcomes; histological stains; imaging modality; improved; innovation; intravital microscopy; longitudinal analysis; mortality; mouse model; neurobehavior; neutrophil; pre-clinical research; prevent; scaffold; therapeutic target

Project Summary/Abstract Up to 30% of patients surviving aneurysmal subarachnoid hemorrhage (aSAH) develop delayed cerebral ischemia and neurological deficits 4-10 days post-SAH which are leading causes of morbidity and mortality. Recent clinical studies indicate that the cause of delayed ischemia and neurological deficits is multifactorial, and includes microthrombi and inflammation. Intravascular microthrombi after aSAH in humans peak 1-2 week post- SAH, mirroring delayed neurological deficit onset, and are significantly higher in the brains of aSAH patients who had delayed deficits vs aSAH patients who did not have delayed deficits. SAH triggers an inflammatory response which has been linked to delayed neurological decline in aSAH patients. Inflammation-induced neutrophil extracellular traps (NETs, extracellular web-like chromatin scaffolds which mediate inflammation and thrombosis) has been reported in aSAH patients, but have not been studied in the context of delayed deficits post-SAH. Our preliminary data in humans and mice suggest that microthrombi and NETs contribute to the development of delayed ischemia and deficits after SAH. So, our central hypothesis is that microthrombi and NETs are causative factors (via lower brain perfusion, small infarcts, and inflammation) for the development of delayed deficits after SAH. This will be the first proposal designed to specifically study delayed neurological deficits using a mouse model of SAH to investigate the potential contributing factors of delayed deficits. Specific Aim 1: Interrogate the role of microthrombi in delayed functional deficits after SAH in mice. Our hypothesis is that microthrombi formation causes a sustained reduction in brain tissue perfusion leading to delayed infarction and delayed functional deficits. To test our hypothesis, we will use prototypic inhibitors of platelet activation to attenuate microthrombi in wild-type and platelet-fluorescent mice subjected to SAH. Various imaging modalities will be used to assess brain perfusion, microthrombi formation, and infarction. Functional performance will be tested daily for 6 days post-SAH. This aim will identify if platelet-inhibition/microthrombi have a substantial influence on delayed SAH injury, including delayed infarction and delayed functional deficits. Specific Aim 2: Investigate the contribution of neutrophil extracellular traps to delayed functional deficits after SAH in mice. Our hypothesis is that NETs contribute to vessel occlusion leading to delayed infarction and deficits. To test this, we will use SAH mice depleted of peripheral neutrophils (with a Ly6G antibody), or treated with Cl-amidine (to prevent NETs) or DNase-I (to lyse NETs). Several imaging modalities will be used to assess brain perfusion, NET formation, infarction, and infiltrating immune cells. Neurobehavior will be tested for 6 days. This aim will determine the role of neutrophil extracellular traps in delayed ischemia and deficits post- SAH. The long-term goals are to determine if microthrombi and/or NETs are key contributors to the development of delayed deficits, and to identify potential therapeutic targets to prevent delayed ischemia and deficits after SAH.

项目概要/摘要 高达 30% 的动脉瘤性蛛网膜下腔出血 (aSAH) 幸存患者会出现迟发性脑出血 SAH 后 4-10 天出现缺血和神经功能缺损，这是发病和死亡的主要原因。 最近的临床研究表明迟发性缺血和神经功能缺损的原因是多因素的， 包括微血栓和炎症。人类 aSAH 后血管内微血栓在术后 1-2 周达到峰值 SAH，反映延迟性神经功能缺损发作，并且在 aSAH 患者的大脑中显着较高 有延迟性缺陷的患者与没有延迟性缺陷的 aSAH 患者相比。 SAH 引发炎症反应 这与 aSAH 患者的迟发性神经功能衰退有关。炎症诱导的中性粒细胞 细胞外陷阱（NET，介导炎症和血栓形成的细胞外网状染色质支架） 在 aSAH 患者中已有报道，但尚未在 SAH 后延迟性功能障碍的背景下进行研究。 我们在人类和小鼠中的初步数据表明，微血栓和 NET 有助于发展 SAH 后迟发性缺血和缺陷。因此，我们的中心假设是微血栓和 NET 是 迟发型发展的致病因素（通过较低的脑灌注、小梗塞和炎症） SAH 后的赤字。这将是第一个旨在专门研究迟发性神经缺陷的提案 SAH 小鼠模型，用于研究延迟性缺陷的潜在影响因素。 具体目标 1：探讨微血栓在小鼠蛛网膜下腔出血后迟发性功能缺陷中的作用。我们的 假设是微血栓的形成导致脑组织灌注持续减少，从而导致 迟发性梗塞和迟发性功能缺陷。为了检验我们的假设，我们将使用原型抑制剂 血小板活化可减轻 SAH 野生型和血小板荧光小鼠中的微血栓。各种各样的 成像方式将用于评估脑灌注、微血栓形成和梗塞。功能性 SAH 后 6 天内每天都会测试性能。该目标将确定血小板抑制/微血栓是否具有 对迟发性 SAH 损伤（包括迟发性梗死和迟发性功能缺陷）有重大影响。 具体目标 2：研究中性粒细胞胞外陷阱对迟发性功能缺陷的影响 小鼠 SAH 后。我们的假设是 NET 会导致血管闭塞，从而导致迟发性梗塞和 赤字。为了测试这一点，我们将使用耗尽外周中性粒细胞（使用 Ly6G 抗体）或经过治疗的 SAH 小鼠 与 Cl-脒（以防止 NET）或 DNase-I（以裂解 NET）混合。将使用多种成像方式来评估 脑灌注、NET 形成、梗塞和浸润免疫细胞。神经行为将进行为期 6 天的测试。 这一目标将确定中性粒细胞胞外陷阱在 SAH 后迟发性缺血和缺陷中的作用。 长期目标是确定微血栓和/或 NET 是否是血栓形成的关键因素 迟发性缺陷，并确定预防 SAH 后迟发性缺血和缺陷的潜在治疗靶点。