PRIMATE MODEL AND PATHOGENESIS OF ANTHRAX SEPSIS

灵长类动物模型和炭疽脓毒症的发病机制

• 批准号: 6867189
• 负责人: Shinichiro Kurosawa
• 金额: $ 49.59万
• 依托单位: OKLAHOMA MEDICAL RESEARCH FOUNDATION
• 依托单位国家: 美国
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-01-15 至 2009-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6867189
• 关键词: Bacillus anthracis; anthrax; anthrax toxin; baboons; bacteria infection mechanism; bioterrorism /chemical warfare; coagulation factor VII; confocal scanning microscopy; disseminated intravascular coagulation; electron microscopy; enzyme linked immunosorbent assay; flow cytometry; heparin; host organism interaction; immunocytochemistry; inflammation; microarray technology; microorganism disease chemotherapy; nonhuman therapy evaluation; pathologic process; protein C; septicemia; spores

DESCRIPTION (provided by applicant): The threat of bioterrorism has become a reality since the attacks with Bacillus anthracis (anthrax) in the fall of 2001. The virulence of B.anthracis depends on a tripartite exotoxin and an anti-phagocytic bacterial capsule. In patients, clinical anthrax is both septicemia and toxemia, with features of an uncompensated inflammatory response. The victims of bioterrorism with inhaled or cutaneous anthrax developed a severe coagulopathy and experienced organ failure and other complications from disseminated intravascular coagulation. These responses are similar to the uncompensated inflammatory responses which contribute directly to the lethality and morbidity in established baboon models of E.coli-mediated sepsis. Activated protein C (APC), a member of the protein C pathway, is an important regulator of this host coagulation and inflammatory response to sepsis. First proposed by our group for the treatment of E.coli-mediated sepsis in the baboon, APC is now an FDA-approved therapy for patients with severe sepsis. The recent phase 3 clinical trial demonstrated that APC as an adjunct to standard anti-infective therapy significantly improved patient outcome. However, the effect of APC has not been tested in sepsis involving an exotoxin. We hypothesize that the protein C pathway plays a major role in modulating responses to B.anthracis septicemia-toxemia and that APC will reduce inflammation and mortality induced by B.anthracis. In order to test this, we will develop i.v. non-human primate models of B. anthracis (toxigenic, non-encapsulated Sterne strain) sepsis and anthrax toxemia. Dose-response studies will establish the concentration ranges of susceptibility. We will use these models to evaluate the contribution of protein C pathway members and other hemostatic regulators to the pathogenesis and lethality of anthrax infection. Antibodies that block the function of protein C pathway members (e.g., protein C, thrombomodulin, endothelial protein C receptor) will be infused with sub-lethal challenge to evaluate individual contributions to inflammatory responses andmortality. Changes at the tissue level (coagulation, inflammation, apoptosis, signaling) will be assessed with immunohistochemical, confocal and electron microscopic imaging and microarrays. Changes in cellular (neutrophil activation) and soluble mediators (e.g, sEPCR, TNF-alpha, IL-6, elastase, D-dimer) will be followed with flow cytometry and ELISAs. Using the baboon models, we will determine the effect of APC administration on mortality and pathological changes induced by B.anthracis or toxin challenge. These studies will establish non-human primate models of anthrax infection, identify molecular pathways unique to toxin action, identify regulatory pathways important to host defense against B.anthracis, provide clinically-relevant animal models for future evaluation of new therapeutic approaches, and determine the role of APC and the protein C pathway in regulating anthrax-mediated pathogenesis.

描述（由申请人提供）： 自2001年秋季炭疽杆菌攻击以来，生物恐怖主义的威胁已成为现实。炭疽B菌的毒力依赖于一种三联外毒素和一种抗吞噬细菌荚膜。临床炭疽病表现为败血症和毒血症，以非代偿性炎症反应为特征。吸入性或皮肤炭疽的生物恐怖主义受害者出现了严重的凝血病，并经历了器官衰竭和弥散性血管内凝血的其他并发症。这些反应类似于未代偿的炎症反应，其直接导致建立的大肠杆菌介导的脓毒症狒狒模型的致死率和发病率。活化蛋白C（APC）是蛋白C通路的一员，是脓毒症宿主凝血和炎症反应的重要调节因子。APC首先由我们的小组提出用于治疗狒狒中大肠杆菌介导的脓毒症，现在是FDA批准的严重脓毒症患者的治疗方法。最近的3期临床试验表明，APC作为标准抗感染治疗的辅助治疗可显著改善患者的预后。然而，APC的作用尚未在涉及外毒素的脓毒症中进行测试。我们推测蛋白C通路在调节对B.炭疽败血症-毒血症的反应中起主要作用，APC将减少由B.炭疽引起的炎症和死亡率。为了验证这一点，我们将开发B的静脉注射非人灵长类动物模型。炭疽（致炎性，非包囊Sterne菌株）脓毒症和炭疽毒血症。剂量反应研究将确定敏感性的浓度范围。我们将使用这些模型来评估蛋白C通路成员和其他止血调节剂对炭疽感染的发病机制和致死率的贡献。阻断蛋白C途径成员功能的抗体（例如，蛋白C、血栓调节蛋白、内皮蛋白C受体）将被注入亚致死性攻击以评估个体对炎症反应和死亡率的贡献。将采用免疫组织化学、共聚焦和电子显微镜成像和微阵列评估组织水平的变化（凝血、炎症、细胞凋亡、信号传导）。将采用流式细胞术和ELISA跟踪细胞（中性粒细胞活化）和可溶性介质（例如sEPCR、TNF-α、IL-6、弹性蛋白酶、D-二聚体）的变化。使用狒狒模型，我们将确定APC给药对由B.炭疽或毒素攻击诱导的死亡率和病理变化的影响。这些研究将建立炭疽感染的非人灵长类动物模型，鉴定毒素作用的独特分子途径，鉴定宿主防御B炭疽的重要调节途径，为未来新治疗方法的评估提供临床相关的动物模型，并确定APC和蛋白C途径在调节炭疽介导的发病机制中的作用。