Intervention strategies of hemorrhagic colitis and HUS

出血性结肠炎和HUS的干预策略

• 批准号: 6524371
• 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/6524371
• 关键词: Escherichia coli 0157:H7; active immunization; colitis; dogs; drug screening /evaluation; hemolytic anemia; hemorrhagic disorders; immunoglobulins; laboratory rabbit; microorganism disease chemotherapy; nonhuman therapy evaluation; passive immunization; renal failure; shiga toxin; 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（由申请人提供）：本提案的主要目标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。 兔子和狗的大肠杆菌（EHEC）感染，以开发治疗方案 预防和治疗肠出血性大肠杆菌疾病。众所周知，志贺毒素 产生 (Stx) 的大肠杆菌菌株，通过摄入不充分的物质而获得 熟肉或其他受污染的食物会引起出血性结肠炎，并可能 诱发致命的溶血性​​尿毒症综合征（HUS）。 EHEC 菌株产生强效 蛋白质毒素被称为志贺样毒素 (Stxs)，因为它们与 志贺氏志贺氏菌毒素。此外，大多数肠出血性大肠杆菌都具有以下能力： 通过“附着和擦除”与肠上皮细胞紧密粘附 (A/E)(7) 机制（图2）。尽管 EHEC 附着机制可能直接 导致腹泻病，并可能影响毒素输送，这是最重要的 EHEC 感染导致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 浸润、细胞因子产生和血管血栓。目前，仅 支持性护理可防止病情发展为重症，并且 EHEC 感染的并发症通常是致命的。策略旨在 减少毒素负担并防止 Stx 与其相互作用 内皮受体应预防或改善靶标疾病和损伤 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 随后应用于肠出血性大肠杆菌疾病的预防和管理。 E. 大肠杆菌RDEC-HI9A菌株感染家兔作为建立动物 用于初步干预研究的肠出血性大肠杆菌疾病模型（目标 1-4）。 RDEC-H19A，由毒素转化噬菌体 H19A 的转移产生 O26:H11 EHEC 为兔致病性大肠杆菌 RDEC-1，是一种附着物 消除产生高水平志贺样毒素 I 的兔子病原体 (Stx-I)，定植于盲肠和结肠，并诱发兔子肠道疾病 其病理变化与人类肠出血性大肠杆菌病相似。具体目标（1-4） 该建议是使用肠出血性大肠杆菌感染的动物模型来： 1)。测试 新毒素受体类似物的能力，通过肠胃外或 肠内预防肠出血性大肠杆菌病。 2）。进一步考验被动能力 给予具有抗毒活性的免疫球蛋白来预防肠出血性大肠杆菌疾病。 3）。进一步检查抗生素治疗是有益还是有害 对病程的影响。 4).进一步制定积极的战略 使用肠出血性大肠杆菌的 Stx 毒素进行免疫接种。 5）。具体目标5是 利用犬特异性 A/E 菌株生产能够感染的新 STEC 狗，易患肾血管病变。我们将转移我们的 将 Stx-1 编码噬菌体标记为狗特异性 A/E 大肠杆菌菌株并进行测试 他们产生肠道和肾脏疾病的能力。临床研究在 布拉德·芬威克 (Brad Fenwick) 博士将在堪萨斯州立大学对狗进行表演。 描述了灰狗的皮肤和肾脏肾小球血管病（CRGV） 暴露于 Stx 的狗。 6).具体目标 6 是扩展我们的兔子和狗模型 能够测试针对表达 Stx-2 的 EBEC 菌株的类似策略。我们 将编码 Stx-2 的毒素转换噬菌体标记并转移至兔子和狗 特定的 A/E 菌株。