MOLECULAR MECHANISMS OF PLATELET THROMBOSIS UNDER FLOW

血流下血小板血栓形成的分子机制

• 批准号: 2392764
• 负责人: JOEL L MOAKE
• 金额: $ 27.89万
• 依托单位: BAYLOR COLLEGE OF MEDICINE
• 依托单位国家: 美国
• 财政年份: 1995
• 资助国家: 美国
• 起止时间: 1995-05-01 至 1999-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2392764
• 关键词: SDS polyacrylamide gel electrophoresis; adenosine diphosphate; autoradiography; cell adhesion; collagen; enzyme activity; enzyme linked immunosorbent assay; flow cytometry; hemodynamics; human subject; molecular pathology; neural cell adhesion molecules; nitric oxide; platelet activation; platelet aggregation; platelets; prostacyclins; proteolysis; radioimmunoassay; stress; thrombosis; tissue /cell culture; vascular endothelium; vasoconstriction; von Willebrand's disease

About 50% of all deaths from illness in the United States each year are caused by thrombi, predominantly composed of platelets, in coronary or cerebral arteries. Although tissue plasminogen activator tPA and streptokinase have been useful in restoring blood flow in acutely occluded coronary arteries, presently available prophylactic agents (e.g., aspirin and ticlopidine) are only moderately effective in preventing the development or recurrence of arterial thrombi in the heart or brain. In order to improve the therapy of arterial thrombotic disorders, basic mechanisms involved in the induction and control of platelet thrombus formation must be better understood. Model systems capable of following in real-time shear stress-induced direct platelet activation and aggregation, as well as platelet-subendothelial adhesion and subsequent aggregation under flow, would be especially useful for this type of study. The use of human blood components and flowing conditions more closely analogous to those encountered in vivo in normal and pathological arteries would improve the in vitro evaluation of prospective anti-arterial thrombotic substances. We propose to utilize our existing real-time flow model of exposed subendothelium for the study of: the interaction of endothelial cell-derived unusually large von Willebrand factor (vWF) multimers with human fibrillar collagen type I (which predominates in atherosclerotic subendothelium) and human collagen type VI (another vWF-binding collagen), and the resulting effects on platelet adhesion; the contribution to thrombosis on collagens I and VI of vWF released from platelets; and the effects on platelet thrombosis of tPA-mediated vWF proteolysis. We will also construct real-time flow models of platelet thrombosis that include endothelial cells and, in order to simulate more closely pathological events that occur in vivo. These latter flow models will enable us to analyze: subendothelial exposure, vWF-mediated platelet-subendothelial adhesion, and subsequent aggregation in a model of vascular injury that includes surrounding endothelial cells; direct shear stress-induced vWF- mediated platelet aggregation in a model of constricted arteries under pathological flow conditions in the presence of intact endothelium; and the modulating effects on vWF-mediated events in these flow models of endothelial cell products (prostacyclin, tissue plasminogen activator, nitric oxide or activity ecto-adenosine diphosphatase).

在美国，每年因疾病死亡的人数中约有 50% 是 由冠状动脉或冠状动脉中主要由血小板组成的血栓引起 脑动脉。尽管组织纤溶酶原激活剂 tPA 和 链激酶可有效恢复急性闭塞的血流 冠状动脉，目前可用的预防药物（例如阿司匹林 和噻氯匹定）对于预防 心脏或大脑中动脉血栓的形成或复发。在 为了改善动脉血栓性疾病的治疗，基础 血小板血栓诱导和控制的机制 必须更好地理解形成。能够遵循的模型系统 实时剪切应力诱导的直接血小板激活和聚集， 以及血小板-内皮下粘附和随后的聚集 在流动下，对于此类研究特别有用。使用 人类血液成分和流动条件更接近于 体内正常和病理动脉中遇到的那些 改善前瞻性抗动脉血栓形成的体外评价 物质。我们建议利用我们现有的实时流模型 暴露的内皮下层用于研究：内皮细胞的相互作用 细胞衍生的异常大的血管性血友病因子 (vWF) 多聚体 I 型人原纤维胶原蛋白（在动脉粥样硬化中占主导地位） 内皮下）和人 VI 型胶原蛋白（另一种 vWF 结合胶原蛋白）， 以及由此产生的对血小板粘附的影响；对的贡献 血小板释放的 vWF 的 I 型和 VI 型胶原蛋白导致血栓形成；和 tPA 介导的 vWF 蛋白水解对血小板血栓形成的影响。我们将 还构建了血小板血栓形成的实时流动模型，包括 内皮细胞，为了更接近地模拟病理 体内发生的事件。后面这些流动模型将使我们能够 分析：内皮下暴露、vWF 介导的血小板内皮下 血管损伤模型中的粘附和随后的聚集 包括周围的内皮细胞；直接剪切应力诱导的 vWF- 在收缩动脉模型中介导血小板聚集 存在完整内皮的病理血流条件；和 在这些流动模型中对 vWF 介导的事件的调节作用 内皮细胞产品（前列环素、组织纤溶酶原激活剂、 一氧化氮或活性外腺苷二磷酸酶）。