HB-EGF and Intestinal Ischemia/Reperfusion

描述（由申请人提供）：尽管最近在诊断和介入医疗保健方面有所改善，但肠缺血/再灌注（I/R）患者的死亡率仍然高得惊人，范围为59- 93%。我们工作的长期目标涉及肝素结合EGF样生长因子（HB-EGF）的临床管理，以保护肠道免受损伤。我们的中心假设是HB-EGF不仅刺激肠上皮细胞增殖和迁移，而且还作为抗炎剂，防止白细胞浸润和激活，并刺激血管生成，愈合反应的重要组成部分。我们的假设基于我们积累的多条证据，证明HB-EGF在肠道I/R后保护肠道。我们提出了三个具体的目标来测试我们的假设，并允许更好地理解HB-EGF功能的机制基础，作为开发治疗方案来治疗这种疾病的必要先决条件。目的[1]检验HB-EGF过度或表达不足（功能获得或丧失）改变对肠I/R的抵抗的假设。我们将比较HB-EGF转基因小鼠、基因敲除小鼠和对照小鼠对失血性休克和复苏的敏感性，测量终点包括：组织学损伤分级、肠道屏障功能和死亡率。此外，将确定损伤后肠道表型的变化。目的[2]验证HB-EGF介导的干扰嗜酸性粒细胞-内皮细胞相互作用有助于HB-EGF保护作用的假设。将确定HB-EGF对活化的PMN和内皮细胞中粘附分子表达的影响以及所利用的信号传导途径。还将测定HB-EGF对血小板减少和粘附分子缺陷小鼠的肠愈合的作用。目的[3]验证HB-EGF促进血管生成的保护作用。将在体外检查HB-EGF介导的血管生成，以确定eNOS、细胞内信号传导途径和EGF受体亚型的作用。还将检查HB-EGF在体内肠损伤后刺激WT和eNOS缺陷型小鼠中血管生成的能力。这项研究计划与公共卫生的相关性将更好地了解HB-EGF在肠道I/R后保护肠道免受损伤的机制，这是开发基于HB-EGF的治疗方案的先决条件。

DESCRIPTION (provided by applicant): Despite recent improvements in diagnostic and interventional health care, mortality rates in patients with intestinal ischemia/reperfusion (I/R) remain alarmingly high, ranging from 59-93%. The long-term goal of our work involves the clinical administration of heparin-binding EGF-like growth factor (HB-EGF) to protect the intestines from injury. Our central hypothesis is that HB-EGF not only stimulates enterocytes to proliferate and to migrate, but also acts as an anti-inflammatory agent that prevents leukocyte infiltration and activation, and stimulates angiogenesis, an important component of the healing response. We base that hypothesis on multiple lines of evidence that we have accumulated demonstrating that HB-EGF protects the intestine after intestinal I/R. We have proposed three specific aims to test our hypothesis, and to allow a better understanding of the mechanistic basis of HB-EGF function, as a necessary prerequisite to developing therapeutic protocols to treat this disease. Aim [1] To test the hypothesis that HB-EGF over- or under- expression (gain or loss of function) alters resistance to intestinal I/R. We will compare the susceptibility of HB-EGF transgenic, knockout and control mice to hemorrhagic shock and resuscitation, with measured endpoints including: histologic injury grading, gut barrier function, and mortality. In addition, intestinal phenotypic changes after injury will be determined. Aim [2] To test the hypothesis that HB-EGF-mediated interference with neutrophil-endothelial cell interactions contributes to the protective effects of HB-EGF. The effect of HB-EGF on adhesion molecule expression in activated PMN and enothelial cells and the signaling pathways utilized will be determined. The effect of HB-EGF on intestinal healing in neutropenic and adhesion molecule-deficient mice will also be determined. Aim [3] To test the hypothsis that stimulation of angiogenesis contributes to the protective effects of HB-EGF. HB-EGF-mediated angiogenesis will be examined in vitro to determine the role(s) of eNOS, intracellular signaling pathways and EGF receptor subtypes. The ability of HB-EGF to stimulate angiogenesis in WT and eNOS deficient mice after intestinal injury in vivo will also be examined. The relevance of this research plan to public health will be a better understanding of the mechanisms utilized by HB-EGF in the protection of the intestines from injury after intestinal I/R, as a prerequisite for the development of HB-EGF-based therapeutic regimens.