循环血中的外泌体在骨科围手术期静脉血栓形成中的作用及机制研究

Venous thrombosis is a leading cause of morbidity and mortality in orthopedic perioperative patients, many risk factors have been identified for venous thrombosis that alter blood flow, activate the endothelium, and increase blood coagulation. However, the precise mechanisms that trigger clotting in large veins have not been fully elucidated. Exosomes, as vehicles of intercellular communication have been associated with initiation and the progression of different diseases, including lots of cardiovascular diseases such as venous thrombosis, coronary artery disease, stroke and peripheral arterial disease. In our previous study, before the formation of venous thrombosis, exosomes were isolated from circulating plasma. The exosomes could activate endothelial cells and cause endothelial cell dysfunction. This project aims to is isolate circulating plasma exosomes before venous thrombosis formation and clarify the relationship between exosomes and the formation venous thrombosis. In addition, to elucidate the function ofexosomes on endothelium inflammatory reaction, apoptosis, aging after uptaken by endothelial cells effect. Furthermore, DIR labeled exosomes injected to IVC Ligation Model from tail vein to test whether exosomes could enrich around the hypoxic endothelial cells and promote thrombosis. Finally, the mechanism of thrombosis formation will be revealed by study the miRNA in exosomes. It is hoped that this study will first reveal the mechanism of early thrombosis emerging in the venous and provide a new molecular target and theoretical basis for further diagnosis and prevention of venous thrombosis, which has important clinical application value.

静脉血栓栓塞是骨科围手术期高发病率和致死率的疾病，尽管血液流速减慢、内皮细胞激活、血液高凝这些危险因素都被证实和血栓形成相关，但其发病机制仍不明确。外泌体作为血液循环中细胞间通讯的重要载体，在心血管疾病的发生发展中起重要作用。本课题组前期研究发现静脉血栓形成前，循环血中的外泌体能激活内皮细胞，导致内皮细胞功能障碍。本项目拟通过分离出静脉血栓形成前，循环血浆中的外泌体，结合体外和体内实验，进一步明确外泌体与静脉血栓形成的关系；阐明外泌体在被内皮细胞摄取后，对内皮细胞炎性反应、凋亡、衰老的作用；在动物模型中，检测其能否在血栓形成处富集并促进血栓的形成。最后，从外泌体中miRNA入手，揭示外泌体促进血栓形成的机制。本研究有希望首先揭示在血栓形成前，血液中的外泌体介导早期血栓的形成及其分子机制，并为进一步的诊断和预防静脉血栓提供新的分子靶点和理论基础，具有重要的临床应用价值。

深静脉血栓（DVT）是全膝关节置换术（TKA）术后常见的的并发症，严重威胁患者的生命安全。研究表明静脉内皮的激活是DVT形成的始动因素，但目前尚未完全阐明TKA激活内皮细胞的分子机制。我们前期研究发现，TKA术后DVT患者和大鼠DVT模型的血浆外泌体可以激活各自种属静脉内皮细胞，并在体内能够促进深静脉血栓的形成。为了探究其发挥作用的机制，我们通过高通量测序，建立TKA术后DVT患者血浆外泌体的miRNA表达谱，锁定miR-206-3p并对其进行深入研究。实验结果进一步显示外泌体中miR-206-3p来自骨骼肌，并可能通过靶向GCH1，抑制一氧化氮（NO）的合成，直接参与静脉内皮的激活和DVT的形成，有望为TKA术后DVT的预防提供新的标靶。