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Role of NO and Endothelin in Human NEC

NO 和内皮素在人类 NEC 中的作用

基本信息

批准号：
7250900
负责人：
GAIL E BESNER
金额：
$ 30.82万
依托单位：
RESEARCH INST NATIONWIDE CHILDREN'S HOSP
依托单位国家：
美国
项目类别：
财政年份：
2003
资助国家：
美国
起止时间：
2003-07-01 至 2011-06-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/7250900
关键词：
Adolescent Affect Animal Model Animals Attenuated Biological Blood Vessels Blood flow Coagulation Process Constriction procedure Consumption Data Databases Development Dilator Disease Endothelin Endothelin Receptor Endothelin-1 Endothelium Enterocolitis Etiology Evaluation Excision Family suidae Gastrointestinal Diseases Goals Growth Harvest Histopathology Human Hypoxia Immunohistochemistry Infant Intestines Ischemia Localized Mediating Medical Mesentery Messenger RNA Mitochondria Monitor Necrosis Necrotizing Enterocolitis Newborn Infant Nitric Oxide Nitric Oxide Synthase Numbers Oxygen Consumption Pathogenesis Patients Perforation Perinatal Physiological Physiological reperfusion Pilot Projects Planet Mars Production Prospective Studies Protein Isoforms Proteins Randomized Controlled Clinical Trials Regulation Reperfusion Therapy Research Design Research Personnel Resected Role S-nitro-N-acetylpenicillamine Site Specimen Testing Therapeutic Time Tissues Vasodilator Agents Western Blotting Work arteriole base cytochrome c oxidase depressive symptoms hemodynamics human NOS2A protein human NOS3 protein human tissue infancy man mortality neonatal morbidity novel pressure programs prospective receptor respiratory vasoconstriction

项目摘要

DESCRIPTION (provided by applicant): The goal of this project is to test, in human intestine, a novel hypothesis regarding the pathogenesis of the ischemia which precedes the development of necrotizing enterocolitis (NEC), the most common acquired gastrointestinal disease of infancy and a major contributor to neonatal morbidity and mortality. The study hypothesis is as follows: the relevant microvascular ischemia preceding NEC is caused by an imbalance between the production of the potent, endothelium-derived vasodilator nitric oxide (NO) and the potent, endothelium-derived constrictor endothelin-1 (ET-1). We contend that expression and activity of the endothelial isoform of nitric oxide synthase (eNOS) is decreased while the expression of ET-1 is increased in intestine afflicted with NEC; as well, we believe that expression of the endothelin ETA receptor, which mediates ET-1-based vasoconstriction, is increased in NEC. This hypothesis was initially developed based on work carried out in perinatal swine, in which we demonstrated that the roles of NO and ET-1 in intestinal vascular regulation are substantially greater in newborn than juvenile swine; furthermore, we demonstrated that a pro-found and sustained imbalance between NO and ET-1 occurs after modest episodes of ischemia-reperfusion. Based on this animal work, we carried out a pilot study in human intestine recovered from resections in NEC and non-NEC patients. This pilot study revealed a decreased expression of eNOS and an increased expression of ET-1 in intestine from NEC patients; as well, mesenteric arterioles harvested from NEC intestine demonstrated a reduced role for endogenous NO in vascular regulation, but an increased role for endogenous ET-1. This application proposes to expand these observations by carrying out a prospective study solely in human intestine. Four specific aims are proposed: Aim [1] will expand observations regarding the expression of eNOS in intestine from NEC and non-NEC cases; additional studies will be carried out to evaluate eNOS activity and localization by immunohistochemistry. The putative contribution of iNOS will also be assessed. Aim [2] will expand observations regarding expression of ET-1 in intestine from NEC and non-NEC cases. We will add the evaluation of ET-1 localization per immunohistochemistry and also evaluate the presence of endothelin receptors. Aim [3] will expand observations regarding the hemodynamic regulation of arterioles harvested from the mesenteric remnants of intestine resected from NEC and non-NEC patients. Studies are designed to evaluate the roles of NO and ET-1 in this regulation, looking for evidence that the role of NO is decreased and of ET-1 is increased in arterioles harvested from NEC intestine. Aim [4] will test the hypothesis that NO directly regulates intestinal oxygen consumption by means of its ability to interact with cytochrome oxidase, specifically, we will determine if NO acts to inhibit mitochondrial respiratory activity and so attenuate intestinal oxygen consumption in a physiological relevant manner. This study is unique in that it will rigorously test a novel hypothesis regarding NEC pathogenesis in human intestine rather than in an animal model. If successful, these data could provide a platform for a prospective, randomized trial of new medical therapeutic strategies for NEC, e.g., the pharmacological manipulation of endothelin receptors.

描述（由申请人提供）：该项目的目标是在人类肠道中测试关于缺血发病机制的新假设，该缺血发病机制先于坏死性小肠结肠炎（NEC）的发展，NEC是婴儿期最常见的获得性胃肠道疾病，也是新生儿发病率和死亡率的一个主要因素。研究假设如下：NEC 之前的相关微血管缺血是由有效的内皮源性血管舒张剂一氧化氮 (NO) 和有效的内皮源性收缩剂内皮素-1 (ET-1) 的产生之间的不平衡引起的。我们认为，在患有 NEC 的肠道中，一氧化氮合酶 (eNOS) 内皮亚型的表达和活性降低，而 ET-1 的表达增加；同样，我们认为，介导基于 ET-1 的血管收缩的内皮素 ETA 受体的表达在 NEC 中增加。这一假说最初是基于在围产期猪中进行的工作而提出的，其中我们证明了新生猪中 NO 和 ET-1 在肠道血管调节中的作用明显大于幼年猪；此外，我们证明，在适度的缺血再灌注发作后，NO 和 ET-1 之间会出现严重且持续的不平衡。基于这项动物工作，我们对 NEC 和非 NEC 患者切除后恢复的人肠道进行了初步研究。这项初步研究揭示了 NEC 患者肠道中 eNOS 表达减少和 ET-1 表达增加；此外，从 NEC 肠道采集的肠系膜小动脉显示内源性 NO 在血管调节中的作用减弱，但内源性 ET-1 的作用增强。本申请建议通过仅在人类肠道中进行前瞻性研究来扩展这些观察结果。提出了四个具体目标：目标 [1] 将扩大对 NEC 和非 NEC 病例肠道中 eNOS 表达的观察；将进行其他研究以通过免疫组织化学评估 eNOS 活性和定位。 iNOS 的假定贡献也将被评估。目标 [2] 将扩大对 NEC 和非 NEC 病例肠道中 ET-1 表达的观察。我们将添加每个免疫组织化学对 ET-1 定位的评估，并评估内皮素受体的存在。目标 [3] 将扩大对从 NEC 和非 NEC 患者切除的肠系膜残余物中采集的小动脉的血流动力学调节的观察。研究旨在评估 NO 和 ET-1 在这种调节中的作用，寻找从 NEC 肠道收获的小动脉中 NO 的作用降低而 ET-1 的作用增加的证据。目标[4]将检验NO通过与细胞色素氧化酶相互作用的能力直接调节肠道耗氧量的假设，具体来说，我们将确定NO是否起到抑制线粒体呼吸活动的作用，从而以生理相关的方式减弱肠道耗氧量。这项研究的独特之处在于，它将在人类肠道而不是动物模型中严格检验有关 NEC 发病机制的新假设。如果成功，这些数据可以为 NEC 新医学治疗策略（例如内皮素受体的药理学操作）的前瞻性、随机试验提供平台。