Trauma and Shock-Induced Microvascular Dysregulation and Coagulopathy

项目主任/首席调查员(最后、第一、中间)：Kozar RA/董建华 项目摘要 创伤是可预防的死亡的主要原因，大多数死亡是由出血和 血管损伤引起的相关并发症(失血性休克[HS])。而出血的结果是 在凝血因子和血小板迅速丧失的情况下，越来越多的证据表明继发性凝血病 从创伤引起的高凝状态迅速发展为消耗性凝血障碍，以及 是HS诱导的低灌流和组织缺血所致的微血管内皮病变的重要组成部分。这个 内皮病造成炎症和氧化应激环境，内皮细胞(ECs) 激活并破坏其屏障功能。这种微血管失调的一个特点是失去了 内皮糖萼，一种由Syndecan-1固定在内皮上的碳水化合物保护层。这个 糖萼保护内皮细胞免受血液和血浆因子的影响，并具有抗炎、抗血栓、 和抗氧化应激分子。随着Syndecan-1胞外结构域的脱落，它在HS后丢失 金属蛋白酶ADAM-17。糖萼的丧失使血管内皮细胞抗凝抗炎 高度促凝血和促炎作用。关键的问题是什么触发脱毛及其病理性 后果。我们最近的数据表明，粘附性配体von Willebrand因子(VWF)和 细胞外小泡(EVS)在创伤后继发的内皮病变和凝血障碍以及由此导致的HS中。在这 在这项研究中，我们建议检验以下假设：1)Syndecan-1与进行性内皮细胞脱落 超粘附性VWF和病理性EVS释放引起的调节失调，2)Syndecan-1脱落被触发 通过与ADAM-17在膜脂筏中聚集，以及3)受体结合A1结构域在 超粘附性VWF通过将炎症细胞和EVS捆绑在糖萼上来增强内皮病变- 剥离的内皮细胞。我们进一步假设，糖基化缺失和糖基化之间的协同作用， 高粘附性VWF和EVS可以被阻断，以防止内皮病变。我们建议对这些假设进行检验 通过分析创伤患者的血浆样本和临床信息，确定导致 Syndecan-1的脱落和VWF体外高黏附活性的结构基础，并测试新的和 在HS小鼠模型中的创新治疗策略有以下三个目的：目的1：确定 进行性微血管调节障碍最终导致出血性损伤患者的血液衰竭 目的2：体外研究Syndecan-1脱落途径和超粘性VWF的结构， 和目标3：测试新的治疗药物以减轻创伤引起的小鼠微血管调节障碍 HS的模型。我们的建议提出了创新的概念和新的机制，提供了一个新的范式 为逆转血管内皮细胞病变和凝血功能障碍奠定基础 作为复苏辅助手段的创新疗法可进一步降低失血性休克相关的发病率和 死亡率。 OMB编号0925-0001/0002(批准的第03/2020版至2023年2月28日)续页格式页

Program Director/Principal Investigator (Last, First, Middle): Kozar RA/ Dong JF Project Summary Trauma is the leading cause of preventable death, with the majority of deaths caused by hemorrhage and associated complications due to injury to the vasculature (hemorrhagic shock [HS]). While hemorrhage results in the rapid loss of coagulation factors and platelets, increasing evidence suggests that secondary coagulopathy develops from a trauma-induced hypercoagulable state that rapidly turns into consumptive coagulopathy, and is an integral part of microvascular endotheliopathy due to HS-induced hypoperfuson and tissue ischemia. The endotheliopathy creates an inflammatory and oxidative stress environment where endothelial cells (ECs) are activated and their barrier function disrupted. A hallmark of this microvascular dysregulation is loss of the endothelial glycocalyx, a protective layer of carbohydrates anchored to the endothelium by syndecan-1. The glycocalyx shields endothelial cells from blood and plasma factors and hosts anti-inflammatory, anti-thrombotic, and anti-oxidative stress molecules. It is lost following HS with shedding of the syndecan-1 ectodomain by the metalloprotease ADAM-17. Loss the of glycocalyx makes the anti-coagulant and anti-inflammatory endothelium highly procoagulant and proinflammatory. The critical question is what triggers shedding and its pathological consequences. Our recent data suggests causal roles of the adhesive ligand von Willebrand factor (VWF) and extracellular vesicles (EVs) in endotheliopathy and coagulopathy secondary to trauma and resultant HS. In this study, we propose to test the hypotheses that: 1) syndecan-1 shedding with progressive endothelial dysregulation caused by release of hyperadhesive VWF and pathologic EVs, 2) syndecan-1 shedding is triggered by clustering with ADAM-17 in membrane lipid rafts, and 3) exposure of the receptor-binding A1 domain on hyperadhesive VWF enhances endotheliopathy by tethering inflammatory cells and EVs to the glycocalyx- stripped endothelium. We further hypothesize that the synergistic interplay between glycocalyx loss, hyperadhesive VWF, and EVs can be blocked to prevent endotheliopathy. We propose to test these hypotheses by analyzing plasma samples and clinical information from trauma patients, defining pathways leading to syndecan-1 shedding and the structural basis of VWF hyperadhesive activity in-vitro, and testing new and innovative therapeutic strategies in mouse models of HS in the following three aims: Aim 1: To determine the progressive microvascular dysregulation culminating in blood failure of injured patients with hemorrhagic shock; Aim 2: To study the pathway of syndecan-1 shedding and the structure of hyperadhesive VWF in-vitro, and Aim 3: To test new therapeutic agents to mitigate trauma-induced microvascular dysregulation in mouse models of HS. Our proposal puts forth innovative concepts and novel mechanisms that offer a new paradigm for the reversal of endotheliopathy and coagulopathy that can establish the foundation for the development of innovative therapeutics as resuscitation adjuncts to further reduce hemorrhagic shock-related morbidity and mortality. OMB No. 0925-0001/0002 (Rev. 03/2020 Approved Through 02/28/2023) Page Continuation Format Page