HB-EGF and Intestinal Ischemia/Reperfusion

描述(申请人提供)：尽管最近诊断和介入医疗保健有所改善，但肠缺血/再灌注(I/R)患者的死亡率仍然高得惊人，从59%到93%不等。我们工作的长期目标包括临床应用肝素结合的EGF样生长因子(HB-EGF)来保护肠道免受损伤。我们的中心假设是，HB-EGF不仅刺激肠上皮细胞的增殖和迁移，而且作为一种抗炎剂，防止白细胞的渗透和激活，并刺激血管生成，这是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目标来检验我们的假设，并允许更好地理解HB-EGF功能的机制基础，作为开发治疗方案治疗这种疾病的必要前提。目的[1]验证HB-EGF过度或低表达(功能增强或丧失)改变肠道I/R抵抗的假说，比较HB-EGF转基因、基因敲除和对照小鼠对失血性休克和复苏的易感性，测量的终点包括：组织学损伤分级、肠道屏障功能和死亡率。此外，还将测定损伤后肠道表型的变化。目的[2]验证HB-EGF介导的中性粒细胞-内皮细胞相互作用的干预有助于HB-EGF的保护作用的假说。HB-EGF对活化的中性粒细胞和血管内皮细胞黏附分子表达的影响以及所采用的信号通路将被确定。HB-EGF对中性粒细胞减少和黏附分子缺陷小鼠肠道愈合的影响也将被确定。目的[3]验证刺激血管生成参与HB-EGF保护作用的假说。体外实验将检测HB-EGF介导的血管生成，以确定eNOS、细胞内信号通路和EGF受体亚型在其中的作用(S)。还将检测HB-EGF对WT和eNOS缺陷小鼠在体内肠道损伤后促血管生成的能力。这项研究计划与公共健康的相关性将是更好地理解HB-EGF在肠I/R后保护肠道免受损伤的机制，作为开发基于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.