Intervention strategies of hemorrhagic colitis and HUS

出血性结肠炎和HUS的干预策略

• 批准号: 6370827
• 负责人: EDGAR C. BOEDEKER
• 金额: $ 28.4万
• 依托单位: UNIVERSITY OF MARYLAND BALTIMORE
• 依托单位国家: 美国
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-08-01 至 2005-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6370827
• 关键词: Escherichia coli 0157:H7; active immunization; colitis; dogs; drug screening /evaluation; enterotoxins; hemolytic anemia; hemorrhagic disorders; immunoglobulins; laboratory rabbit; microorganism disease chemotherapy; nonhuman therapy evaluation; passive immunization; renal failure; vascular endothelium

DESCRIPTION (provided by applicant): The broad aim of this proposal is to develop and utilize new and established animal model of enterohemorrhagic E. coli (EHEC) infection, in rabbits and dogs, to develop therapeutic regimens to prevent and treat EHEC disease. It is well recognized that shiga-toxin- (Stx)-producing strains of E. coli, acquired by ingestion of inadequately cooked meat, or other contaminated foods, cause hemorrhagic colitis, and may induce fatal hemolytic uremic syndrome (HUS). EHEC strains produce potent protein toxins named Shiga-like toxins (Stxs) because of their relatedness to Shiga toxin of Shigella dysenteriae. In addition, most EHEC share the ability to adhere intimately to intestinal epithelial cells by "attaching and effacing" (A/E)(7) mechanisms (Fig.2). Although EHEC attachment mechanisms may directly contribute to diarrheal disease, and may influence toxin delivery, the most severe intestinal and renal manifestations of EHEC infection result from toxin-mediated damage to vascular endothelium, with tissue edema, inflammatory infiltrates, cytokine production and vascular thrombi. At present, only supportive care is available to prevent the development of the severe, and frequently fatal, complications of EHEC infection. Strategies aimed at decreasing the toxin burden and preventing the interaction of Stxs with their endothelial receptors should prevent or ameliorate disease and damage in target organs (gut, CNS and kidney). Interventions developed in animal models can subsequently be applied to the prevention and management of EHEC disease. E. coli strain RDEC-HI9A infection of rabbits serves as the established animal model of EHEC disease for the initial intervention studies (Aims 1-4). RDEC-H19A, produced by the transfer of the toxin-converting phage H19A of an O26:H11 EHEC to the rabbit entero-pathogenic E. coli RDEC-1, is an attaching and effacing rabbit pathogen which produces high levels of Shiga-like toxin I (Stx-I), colonizes cecum and colon, and induces intestinal disease in rabbits with pathologic changes resembling human EHEC disease. Specific aims (1-4) of the proposal are to use animal models of EHEC infection to: 1). Test the ability of new toxin-receptor analogs, administered paretenteraly or enterically to prevent EHEC disease. 2). Further test the ability of passively administered immunoglobulin with anti-toxic activity to prevent EHEC disease. 3). Further examine whether antibiotic therapy has beneficial or harmful effects on the course of disease. 4). Further develop strategies for active immunization against EHEC using the Stx toxins of EHEC. 5). Specific aim 5 is to utilize canine specific A/E strains to produce new STECcapable of infecting dogs, which are susceptible to renal vascular lesions. We will transfer our labeled Stx-1 encoding phage to dog-specific A/E strains of E. coli and test their ability to produce intestinal and renal disease. The clinical studies in dogs will be performed at Kansas State University by Dr. Brad Fenwick who has described the Cutaneous and Renal Glomerular Vasculopathy (CRGV) in greyhound dogs exposed to Stx. 6). Specific Aim 6 is to extend our rabbit and dog models to be able to test similar strategies against EBEC strains expressing Stx-2. We will label and transfer toxin converting phage encoding Stx-2 to rabbit and dog specific A/E strains.

描述(申请人提供)：本提案的主要目的是开发和利用新的和已建立的肠出血性大肠杆菌动物模型。 大肠杆菌(EHEC)感染，在兔和狗身上，开发治疗方案以 防治肠出血性肠出血性疾病。我们都知道志贺毒素- (STX)产生菌，因摄入不足而获得 熟肉或其他受污染的食物会导致出血性结肠炎，并可能 导致致命性溶血性尿毒症综合征(HUS)。EHEC菌株产生强效 蛋白类毒素命名为志贺样毒素(Stxs)，因为它们与 志贺氏痢疾杆菌志贺毒素。此外，大多数EHEC都具有这种能力 通过“附着和去除”与肠上皮细胞紧密黏附 (A/E)(7)机制(图2)。尽管EHEC附着机制可以直接 导致腹泻疾病，并可能影响毒素的传递，最大 肠出血性大肠杆菌感染引起严重的肠道和肾脏表现 毒素介导的血管内皮损伤，伴有组织水肿、炎症 渗出、细胞因子的产生和血管血栓。目前，只有 提供支持性护理以防止重症患者的发展，以及 肠出血性大肠杆菌感染的并发症，通常是致命的。旨在实现以下目标的战略 降低毒素负担，防止STX与其相互作用 内皮受体应预防或改善靶区的疾病和损伤 器官(肠道、中枢神经系统和肾脏)。在动物模型中开发的干预措施可以 随后将其应用于EHEC疾病的预防和管理。E. 大肠杆菌RDEC-HI9A株感染兔作为建立的动物 EHEC病模型的初步干预研究(目标1-4)。 RDEC-H19A，由转化毒素的噬菌体H19A转移产生 O26：H11 EHEC对兔肠道致病性大肠杆菌RDEC-1的附着性 消除产生高水平志贺毒素I的兔病原体 (STX-I)，在盲肠和结肠定植，并诱导肠道疾病 具有类似于人类EHEC疾病的病理变化。具体目标(1-4) 建议使用EHEC感染的动物模型：1)。测试 新的毒素受体类似物经腹或腹膜外给药的能力 肠道预防肠出血性肠出血性疾病。2)。进一步测试被动学习的能力 注射具有抗毒性活性的免疫球蛋白预防EHEC疾病。 3)。进一步检查抗生素治疗是否有益或有害 对病程的影响。4)。进一步制定积极主动的战略 利用EHEC的STX毒素免疫EHEC。5)。具体目标5是 利用犬特异型甲型肝炎病毒株培育新的致病毒株 狗，这是易感的肾血管损伤。我们将把我们的 编码犬特异性A/E菌株的噬菌体标记STX-1及其检测 它们产生肠道和肾脏疾病的能力。年的临床研究 狗将在堪萨斯州立大学由布拉德·芬威克博士表演，他已经 描述灰狗皮肤和肾小球血管病(CRGV) 暴露在STX下的狗。6)。具体目标6是扩展我们的兔子和狗的模型 能够对表达STX-2的EBEC菌株测试类似的策略。我们 将标记并将编码STX-2的噬菌体转化毒素转移给兔和狗 特定的A/E菌株。