Severe Trauma Provokes Pathologic Continuum of Plasmin Activation

1项目摘要：严重创伤是造成死亡和残疾的重要原因。在康复早期，它会导致 2出血、血栓形成和多器官功能障碍综合征；在恢复期后期，它会引发病理 3组织修复和动态平衡，妨碍恢复日常生活活动。严重创伤相关死亡 伤残与凝血的病理性激活程度直接相关(创伤- 5诱发凝血障碍(TIC)和炎症(全身炎症反应综合征(SIRS)) 6减轻TIC和/或SIRS将减少严重创伤引起的并发症。有一个关键的知识 7关于严重创伤后TIC和SIRS的分子煽动者的差距。我们的初步数据支持 8一种变革性的假说，牵涉到纤溶酶的不适当的早期激活，这是 9组织修复和内稳态所必需的纤溶系统，作为启动TIC和SIRS的关键事件， 10这还会导致纤溶酶活性的长期丧失，从而扰乱组织修复和动态平衡。前提： 11在孤立的创伤后，纤溶酶原的激活受到严格的调控，并限制在伤口部位。 然而，在严重创伤后，纤溶酶被系统激活(纤溶功能亢进)，随后是长期的 13纤溶酶活性低下(纤溶功能低下)，两者均与预后不良有关。我们的中央 14假设：(1)严重创伤后早期纤溶亢进是TIC和SIRS的主要促进剂， 15(Ii)早期纤溶亢进通过耗尽纤溶酶原而导致纤溶低下，而(Iii)获得性 16纤溶酶原缺乏是病理组织动态平衡和修复的驱动因素。方法和途径： 17采用小鼠烧伤作为严重创伤的典型模型，我们将在目标1中确定 18早期纤溶亢进加速TIC和SIRS，目的2早期纤溶亢进是否导致迟发性 19例出现持续性纤溶功能低下。纤溶酶活性将被药物抑制/增强，并使用 20种新型分子工具。TIC和SIRS将通过已建立的生物标记物、血小板的系列分析进行评估 21功能和器官特异性核因子-κB定量作为多器官功能障碍综合征的替代指标。 22纤溶系统将通过量化其个别成分、蛋白酶-抑制物复合体、 23种纤维蛋白降解产物，并进行活性测定。接下来，在目标3中，我们将结合小鼠烧伤模型和 24股骨骨折和骨骼肌损伤模型评估晚期纤溶低下是否导致骨相关 25种病理；特别是骨折愈合受损、肌肉异位骨化和创伤诱发 骨质疏松症26例。在分子水平上，我们将确定恢复纤溶酶活性是否会阻止这些骨骼 27并发症以及骨病理过程在多大程度上是由纤维蛋白或纤维蛋白介导的 炎症28例。综上所述，如果这些发现属实，将为1)抑制纤溶酶原提供支持 29在康复早期激活以部分防止TIC和SIRS，以及2)纤溶酶原复苏， 30或在后期康复期间促进纤溶的替代方法，以保持骨骼健康。

1 Project Summary: Severe trauma is a significant cause of death and disability. Early in convalescence, it causes 2 bleeding, thrombosis and multi-organ dysfunction syndrome; later in convalescence, it instigates pathologic 3 tissue repair and homeostasis, which prevents return to activities of daily living. Severe trauma related death 4 and disability is directly correlated with the degree of activation of pathologic activation of coagulation (trauma- 5 induce coagulopathy (TIC)) and inflammation (systemic inflammatory response syndrome (SIRS)) suggesting 6 that mitigating TIC and/or SIRS would reduce complications caused by severe trauma. There is a key knowledge 7 gap regarding the molecular instigators of TIC and SIRS following severe trauma. Our preliminary data support 8 a transformative hypothesis that implicates inappropriate early activation of plasmin, the principle protease of 9 the fibrinolytic system essential for tissue repair and homeostasis, as a key event that initiates TIC and SIRS, 10 that also results in a prolonged loss of plasmin activity that disrupts tissue repair and homeostasis. Premise: 11 Following an isolated trauma, plasminogen activation is tightly regulated and restricted to the wound site. 12 However, following a severe trauma, plasmin is systemically activated (hyperfibrinolysis) followed by a prolonged 13 deficit of plasmin activity (hypofibrinolysis), both of which are associated with poor outcomes. Our central 14 hypothesis is that (i) early hyperfibrinolysis following severe trauma is a primary accelerant of TIC and SIRS, 15 (ii) early hyperfibrinolysis causes hypofibrinolysis by exhausting plasminogen, and that (iii) the acquired 16 plasminogen deficiency is a driver of pathologic tissue homeostasis and repair. Methods & Approach: 17 Employing a murine burn injury as a representative model of severe trauma, we will determine in Aim 1 whether 18 early hyperfibrinolysis accelerates TIC and SIRS and in Aim 2 whether early hyperfibrinolysis causes late 19 sustained hypofibrinolysis. Plasmin activity will be pharmacologically inhibited/enhanced and measured using 20 novel molecular tools. TIC and SIRS will be assessed with serial analysis of established biomarkers, platelet 21 function, and organ specific NF-κB quantification as a surrogate measure of multiorgan dysfunction syndrome. 22 The fibrinolytic system will be assessed by quantifying its individual elements, protease-inhibitor complexes, 23 fibrin degradation products, and activity assays. Next, in Aim 3 we will combine the murine burn model with a 24 femur fracture and skeletal muscle injury model to assess whether late hypofibrinolysis causes bone-related 25 pathologies; specifically impaired fracture healing, heterotopic ossification in muscle, and trauma-induced 26 osteoporosis. At the molecular level, we will determine if restoring plasmin activity prevents these bone 27 complications and to what extent of the bone pathologic processes are due to fibrin, or fibrin mediated 28 inflammation. Taken together, if true, these findings would provide support for 1) inhibition of plasminogen 29 activation during the early convalescence to prevent, in part, TIC and SIRS and 2) resuscitation of plasminogen, 30 or alternative means of promoting fibrinolysis, during late convalescence, to preserve bone health.