Evaluation of stability and safety of platelet-like particles for treating bleeding after trauma

项目总结 失控出血是平民和军事创伤中的一个重大临床问题； 在这两种情况下，住院前失血都是导致男性和女性死亡的主要原因。 此外，创伤后的愈合可能会因感染、瘢痕疙瘩形成、血流不足、 或糖尿病和肥胖症等疾病。血栓形成是创伤后止血的关键 包括激活循环中的血小板，使其磨练到损伤部位并聚集形成血小板 堵塞，止血。活化的血小板还结合在损伤部位形成的纤维蛋白纤维形成血小板- 纤维蛋白网。然后，血小板利用肌动蛋白-肌球蛋白机械向凝块网络施加力，收缩和 稳定血栓并促进其作为临时基质的作用，以支持随后的细胞渗透 伤口环境。在创伤的情况下，失血会导致血小板耗尽， 削弱了他们止血和促进愈合的能力。输注血小板是目前的护理标准； 然而，孤立的血小板的保质期很短，导致了重大的供应链问题。另外， 与输血产品相关的潜在免疫学问题突出了关键的未得到满足的需求 开发治疗创伤后出血的血小板替代品。我们最近开发出了合成的类血小板 粒子(PLP)由高度变形的微粒与纤维蛋白靶向基序结合而成，能够 通过与损伤部位形成的纤维蛋白高亲和力结合来磨练损伤。我们的初步研究 证明PLP能够概括天然血小板的几种功能，包括凝血增强 在体外，减少在体鼠创伤模型的出血次数和总失血量，并改善 损伤后体内的愈合反应。该项目的长期目标是开发止血PLP，用于 急诊药物应用以增强凝血和减少失血和相关死亡 失血过多。该应用的目的是评估PLPS的长期稳定性和安全性。我们的 中心假设是，与天然血小板相比，PLP的保质期明显更长，而 将最大耐受剂量维持在远高于治疗剂量的水平，从而支持将 技术向前推进到进一步的临床前开发。本项目的具体目标是：1)确定PLP 稳定性和2)确定最大耐受量。

PROJECT SUMMARY Uncontrolled bleeding is a significant clinical problem in both civilian and military traumatic injuries; in both cases, exsanguination prior to hospitalization is the primary cause of death for both men and women. Furthermore, healing following trauma can be complicated by infection, keloid formation, insufficient blood flow, or conditions such as diabetes and obesity. Clot formation is critical to the cessation of bleeding after trauma and involves the activation of circulating platelets that hone to the site of injury and aggregate to form a platelet plug, stemming bleeding. Activated platelets also bind fibrin fibers forming at a site of injury to form a platelet- fibrin mesh. Platelets then utilize actin-myosin machinery to apply forces to the clot network, contracting and stabilizing the clot and facilitating its role as a provisional matrix to support subsequent cellular infiltration of the wound environment. In cases of traumatic injury, exsanguination can cause platelets to become depleted, impairing their ability to stop bleeding and promote healing. Platelet transfusion is the current standard of care; however, isolated platelets have a short shelf-life, contributing to major supply chain issues. Additionally, potential immunologic concerns associated with transfusion of blood products highlights the critical unmet need to develop platelet alternatives to treat bleeding after trauma. We have recently developed synthetic platelet-like particles (PLPs) created from highly deformable microparticles coupled to fibrin-targeting motifs that are capable of honing to injuries through high affinity binding to fibrin forming at the sites of injury. Our initial studies demonstrate that PLPs are able to recapitulate several functions of native platelets, including clot augmentation in vitro, decreasing bleeding times and overall blood loss in in vivo rodent models of trauma, and improved healing responses in vivo following injury. The long-term goal of this project is to develop hemostatic PLPs for emergency medicine applications to augment clotting and decrease blood loss and associated deaths due to exsanguination. The objective of this application is to evaluate the long-term stability and safety of PLPs. Our central hypothesis is that PLPs will have significantly superior shelf-life compared to native platelets while maintaining a maximum tolerated dose well above their therapeutic dosage, thereby supporting moving this technology forward into further preclinical development. The specific aims of this project are: 1) Determine PLP stability and 2) Determine maximum tolerated dose.