Role of Calpain in Diabetic Endothelial Dysfunction

心血管疾病占人口发病率和死亡率的绝大部分， 所有类型的糖尿病患者。高血压被认为是一个重要的病因， 糖尿病血管并发症的最初诱因临床证据表明，心血管 糖尿病患者的疾病作为高血糖持续时间的函数而增加， 血管系统对环境葡萄糖升高的反应导致全身性内皮功能障碍，加速了 动脉粥样硬化过程，并损害微循环的重要功能。的结果 在高血糖的情况下，糖尿病血管系统经历异常炎症过程，其特征在于 一氧化氮（NO）释放受损，内皮细胞增殖增加。Calpains是一个家族， 钙依赖性蛋白酶，其最近被牵连在急性炎症性疾病的 心血管系统在初步的研究中，我们发现抑制钙蛋白酶 活性保留内皮NO的释放并减弱炎性白细胞-内皮相互作用 在高血糖时的微循环中。我们的数据强烈支持钙蛋白酶在 糖尿病血管疾病的病理生理学，表明钙蛋白酶抑制剂在糖尿病血管疾病中的潜在有益作用。 糖尿病因此，我们建议研究钙蛋白酶在炎症反应中的作用， 急性和慢性高血糖期间的微循环。我们将检验钙蛋白酶引起 通过研究高血糖期间血管炎症是否：（1）钙蛋白酶活性异常 增加;（2）抑制钙蛋白酶活性可防止微循环中的炎症事件;（3） 钙蛋白酶活性增加下调eNOS酶，导致NO生理水平的丧失;（4） 钙蛋白酶激活增加内皮细胞表面促炎粘附表达 通过上调NF-IcB活性来调节分子。我们将利用以下体内和体外细胞 生理学技术：活体显微镜，静态和流动条件下微血管内皮细胞培养 条件，体内和体外NO测量，免疫组织化学，Western印迹分析，和凝胶电泳。 偏移测定。通过这些方法，本研究将阐明重要和新颖的机制 糖尿病的微血管功能障碍这些信息应提供一个框架， 开发用于治疗危及生命的疾病糖尿病的新的治疗策略。

Cardiovascular disease accounts for an overwhelming proportion of the morbidity and mortality suffered by patients with all forms of diabetes. Hyperglycemia is considered an important etiologic factor that serves as the initial trigger for diabetic vascular complications. Clinical evidence demonstrates that cardiovascular disease in diabetic patients increases as a function of the duration of hyperglycemia and that exposure of the vasculature to elevated ambient glucose causes generalized endothelial dysfunction, accelerates the atherosclerotic process, and impairs important functions of the microcirculation. As a consequence of hyperglycemia, the diabetic vasculature experiences abnormal inflammatory processes characterized by impaired release of nitric oxide (NO) and increased endothelial adhesiveness. Calpains are a family of calcium-dependent proteases, which have been recently implicated in acute inflammatory disorders of the cardiovascular system. In preliminary studies, we have made the novel observation that inhibition of calpain activity preserves release of endothelial NO and attenuates inflammatory leukocyte-endothelium interactions in the microcirculation during hyperglycemia. Our data strongly support a role for calpains in the pathophysiology of diabetic vascular disease, suggesting a potentially beneficial effect of calpain inhibition in diabetes. Therefore, we propose to study the role of calpains in the inflammatory response of the microcirculation during acute and chronic hyperglycemia. We will test the hypothesis that calpains cause vascular inflammation during hyperglycemia by studying whether: (1) calpain activity is abnormally increased; (2) inhibition of calpain activity prevents inflammatory events in the microcirculation; (3) increased calpain activity downregulates the eNOS enzyme leading to loss of physiologic levels of NO; (4) activation of calpains increases endothelial cell surface expression of pro-inflammatory adhesion molecules via upregulation of NF-IcB activity. We will utilize the following in vivo and in vitro cell physiology techniques: intravital microscopy, culture of microvascular endothelial cells under static and flow conditions, NO measurements in vivo and in vitro, immunohistochemistry, Western blot analysis, and gel shift assays. By these means, the studies in this proposal will elucidate important and novel mechanisms underlying microvascular dysfunction in diabetes. This information should provide a framework for developing new therapeutic strategies for the treatment of the life-threatening disorder, diabetes mellitus.