Complement inhibition as sepsis therapy

描述(申请人提供)：严重的脓毒症导致全身炎症，其中凝血和补体激活起关键作用。来自患者和动物模型的证据表明，脓毒症是一种多阶段、多因素的疾病，其早期对入侵细菌的雷状炎症反应导致低灌注量和缺血再灌注(IR)损伤，演变为多器官衰竭(MOF)，最终导致死亡。我们实验室的工作表明，使用亚致死剂量的大肠杆菌在动物中诱导的严重败血症是由两个阶段的一系列事件发展而成的，每个阶段都由不同的病理生理因素驱动。第一阶段事件是由病原体的直接作用引起的，而第二阶段事件是由于IR后宿主异常恢复的结果。这项建议的目的是调查单独抑制补体激活或联合治疗是否可以预防多器官功能衰竭并改善脓毒症的结局。目的1将使用C3转化酶抑制剂来确定补体在脓毒症的两个阶段中的作用，评估补体激活作为脓毒症中血小板减少的潜在原因，并确定补体抑制在脓毒症进展过程中的器官特异性保护作用。本研究将利用基因芯片、免疫细胞化学、电子显微镜和重要器官的生化分析来确定补体激活产物在控制脓毒症进展的主要病理生理过程中的作用。目的2确定在我们的脓毒症模型中，用重组凝集素样区的血栓调节蛋白(TM-LLD)抑制补体是否可以预防器官衰竭并改善预后。目的3将确定与单独抑制补体相比，补体阻断与CD14或细胞外组蛋白的免疫抑制相结合是否可以提供更好/更多的治疗效果。这个项目有可能促进我们对补体激活在脓毒症进展中的作用的理解，并测试补体抑制是否可以作为有效的治疗方法来治疗脓毒症所致的器官衰竭。)

DESCRIPTION (provided by applicant): Severe sepsis leads to systemic inflammation, wherein coagulation and complement activation play critical roles. Evidence from patients and animal models suggest that sepsis is a multi-stage, multi-factorial disease in which the early fulminate inflammatory response to the invading bacteria leads to hypo-perfusion and ischemia-reperfusion (IR) injury that evolves to multiple organ failure (MOF) and ultimately to death. Work from our lab has demonstrated that severe sepsis induced in animals by using sublethal doses of E. coli develops as two-stage series of events, each stage being driven by different pathophysiologies. First stage events are caused by the direct effects of the pathogen, whereas the second stage occurs as result of an aberrant host recovery after IR. The objectives of this proposal are to investigate whether inhibition of complement activation alone or as combination therapies could prevent MOF and improve the outcome of sepsis. Aim 1 will use a C3 convertase inhibitor to determine the role of complement during each of the two stages of sepsis, assess complement activation as a potential cause of thrombocytopenia in sepsis and identify organ- specific protective effects of complement inhibition during sepsis progression. This research will employ cDNA microarray, immunocytochemistry, electron microscopy and biochemical analysis of vital organs to identify the effect of complement activation products on the dominant pathophysiologic processes controlling the progression of sepsis. Aim 2 will determine if, and through what mechanisms, complement inhibition by the recombinant lectin-like domain of thrombomodulin (TM-LLD) could prevent organ failure and improve outcome in our sepsis model. Aim 3 will determine whether combining complement blockade with immunological inhibition of CD14 or extracellular histones could provide superior/additional effects therapeutic effects on E. coli sepsis as compared to complement inhibition alone. This project has potential to advance our understanding of the role of complement activation in sepsis progression and to test whether complement inhibition could be used as effective therapy for sepsis-induced organ failure. )