Platelet-like particles for augmenting hemostasis

项目摘要 失控出血是普外科、创伤和急诊的重大临床挑战。 医药。失血(出血)是创伤(约40%)和出血死亡的主要原因 在体外循环等侵入性手术后，发病率和 死亡率。在正常的凝血级联过程中，蛋白酶凝血酶被激活，而凝血酶又被激活 休眠的循环中的血小板和凝血蛋白前体纤维蛋白原。激活的血小板形成一种 止血塞在损伤部位，止血。血小板足以在短期内达到 止血，并通过其在纤维蛋白募集中的活性对稳定的纤维蛋白血栓成熟至关重要 和血栓收缩。因此，它们在出血或活动期间大量稀释也就不足为奇了。 手术中的抑制会导致凝血系统的故障。目前的止血技术包括 局部密封剂、放热沸石和重组凝血因子。这些方法中的每一个都有 都取得了不大的成功，但都有明显的缺点，比如缺乏伤口特异性；没有一个是 就像天然的伤口反应止血系统一样“进化”。因此，最近的努力集中在 制造人工合成的血小板类似物。我们想要重述的重要的血小板功能包括 损伤引发的纤维蛋白凝块形成和凝块收缩/稳定的增强。到目前为止，人工的 血小板途径仅在非触发(即构成)和非特异性的凝块/血小板结合中重现 时尚，缺乏其他关键的血小板功能。在这里，我们提出了一种新颖而简单的方法来 通过应用合成生物学创造出类血小板结构。我们提出了两个目标。 第一个目标是了解我们的血小板样颗粒如何与凝血的不同阶段相互作用。 并了解我们的血小板样颗粒在增强 止血。第二个目的是探索血小板样颗粒的体内功能，特别是在 在多种创伤相关凝血障碍模型中加强止血。

Project Abstract Uncontrolled bleeding represents a significant clinical challenge in general surgery, trauma, and emergency medicine. Exsanguination (bleeding) is the major cause of death from traumatic injury (~ 40%) and bleeding following invasive surgeries such as cardiopulmonary bypass is associated with significant morbidity and mortality. During the normal clotting cascade, the protease thrombin is activated, which in turn activates dormant circulating platelets and the clotting protein precursor, fibrinogen. Activated platelets form a hemostatic plug at the site of injury, stemming blood loss. Platelets are sufficient to achieve short-term hemostasis and are critical to the maturation of stable fibrin-based clots via their activity in fibrin recruitment and clot contraction. Thus, it is not surprising that their massive dilution during hemorrhage or active inhibition during surgery results in a failure of the clotting system. Current hemostasis technologies include topical sealants, exothermic zeolites and recombinant clotting factors. Each of these approaches has demonstrated modest successes, yet all have significant drawbacks such as a lack of wound specificity; none are as “evolved” as the natural wound-responsive hemostasis system. Thus, more recent efforts have focused on creation of synthetic analogs of platelets. The vital platelet functions that one would like to recapitulate include injury-triggered enhancement of fibrin clot formation and clot contraction/stabilization. To date, artificial platelet approaches only recapitulate clot/platelet binding in a non-triggered (i.e. constitutive) and non-specific fashion and lack the other critical platelet functions. Here we propose a novel and simple approach to the creation of platelet-like structures through the application of synthetic biology. We are proposing two aims. The first aim is to understand how our platelet-like particles interact with various stages of the coagulation cascade and to understand the fundamental mechanism of action of our platelet-like particles in augmenting hemostasis. The second aim is to explore the in vivo function of the platelet-like particles, specifically in the augmentation of hemostasis in multiple models of trauma-associated coagulopathy.