Alpha-Defensins in perioperative thrombosis

 描述(由申请人提供)：手术会增加血栓形成的风险，但在围手术期预防和处理血栓栓塞性疾病会因出血的风险而复杂化。中性粒细胞(PMN)在伤口愈合中起着至关重要的作用，但它们对围手术期血栓形成的贡献以及对血栓预防的影响现在正在显现。中性粒细胞附着在伤口和血管系统上，产生一种独特的局部隔离，这种隔离富含酶和抗菌肽，可防止血浆抑制物，部分通过有序的形成和溶解来促进天然免疫。 纤维蛋白。我们假设术后和持续性炎症破坏了这种平衡，通过促进纤维蛋白的形成和持久性而易于血栓形成。我们以前观察到，a-防御素(a-def)是一种抗菌肽，占人类PMN总蛋白的5%，在激活时释放出来，促进凝血和抑制纤溶。小鼠中性粒细胞中缺乏α-def阻碍了对这些多肽如何在围手术期导致血栓栓塞性疾病的更好理解。利用一种新的表达PMN a-def(def++)的转基因小鼠，我们发现a-def在与纤维蛋白原的复合体中循环，在体外促进纤维蛋白的聚合和回缩，在血管中沉积，诱导闭塞性动脉和静脉血栓形成，并在体内抑制肺血栓的溶解。这些致病特性可以通过移植Def++小鼠的骨髓转移到野生型动物身上，并可以通过免疫耗竭PMN或使用秋水仙素抑制a-def的释放来预防和逆转。我们现在提出了一种综合的方法来了解PMN a-def对围手术期血栓形成的机制和意义，通过检查：a)a-def对血栓形成和结构的生物物理效应；b)Def++小鼠加速血栓形成和纤溶受损的机制以及阻断a-def释放的有益效果；以及c)a-def表达作为手术后静脉血栓栓塞症风险的生物标记物的应用。这些研究将深入了解PMNα-def对动脉和静脉血栓形成的未被认识的贡献，识别手术相关血栓形成风险患者的新的基因和蛋白质生物标志物，并为在围手术期使用安全有效的干预措施预防血栓形成提供证据。

 DESCRIPTION (provided by applicant): Surgery increases the risk of thrombosis but prevention and management of thromboembolic disease in the perioperative period is complicated by the risk of hemorrhage. Neutrophils (PMNs) play a vital role in wound healing, but their contribution to perioperative thrombosis and implications for thromboprophylaxis are now emerging. Adherence of PMNs to wounds and to the vasculature generates a unique localized sequestrum enriched in enzymes and antimicrobial peptides protected from plasma inhibitors that contribute to innate immunity in part through the orderly formation and dissolution of fibrin. We posit that post-operative and persistent inflammation disrupt this balance, predisposing to thrombosis by promoting formation and persistence of fibrin. We have previously observed that a-defensins (a-def), antimicrobial peptides that constitute 5% of total human PMN protein that are released upon activation, promote clotting and inhibit fibrinolysis. The absence of a-def in murine PMNs has hindered a better understanding of how these peptides contribute to thromboembolic disease in the perioperative setting. Using a novel transgenic mouse that expresses PMN a-def (Def++), we show that a-def circulates in a complex with fibrinogen and promotes polymerization and retraction of fibrin in vitro, deposits in the vasculature, induces occlusive arterial and venous thrombosis, and inhibits lysis of pulmonary emboli in vivo. These pathogenic properties can be transferred to wild type animals by transplanting bone marrow from Def++ mice and can be prevented and reversed by immunodepleting PMNs or by inhibiting a-def release using colchicine. We now propose an integrated approach to understanding the mechanism and implications of PMN a-def on perioperative thrombosis by examining: a) The biophysical effects of a-def on clot formation and structure; b) The mechanism of accelerated thrombosis and impaired fibrinolysis in Def++ mice and the salutary effect of blocking a-def release; and c) The utility of a-def expression as a biomarker for risk of venous thromboembolism post- surgery. These studies will provide insight into an unappreciated contribution of PMN a-def to arterial and venous thrombosis, identify novel genetic and protein biomarkers of patients at risk for surgery related thrombosis and provide evidence for the use of a safe and effective intervention to prevent thrombosis in the perioperative period.