Role of Calpain in Diabetic Endothelial Dysfunction

心血管疾病占中国人发病率和死亡率的压倒性比例。 所有形式的糖尿病患者。高血糖被认为是一种重要的病因， 糖尿病血管并发症的最初诱因。临床证据表明，心血管疾病 糖尿病患者的疾病增加是高血糖持续时间和暴露于 血管系统对环境葡萄糖的升高会导致全身性内皮功能障碍，加速 动脉粥样硬化过程，并损害微循环的重要功能。作为一个结果 高血糖，糖尿病血管经历异常炎症过程，其特征是 抑制一氧化氮(NO)的释放，增加内皮细胞的粘附性。钙痛症是一种 钙依赖的蛋白酶，最近被认为与急性炎症性疾病有关 心血管系统。在初步研究中，我们进行了一项新的观察，即抑制钙蛋白酶 活性维持内皮细胞一氧化氮的释放，并减弱炎性白细胞与内皮细胞的相互作用 在高血糖时的微循环中。我们的数据有力地支持了CalPain在 糖尿病血管病变的病理生理学，提示钙蛋白酶抑制在糖尿病血管疾病中具有潜在的有益作用 糖尿病。因此，我们建议研究钙调蛋白在炎症反应中的作用。 急性和慢性高血糖时的微循环。我们将检验由钙痛引起的假说 研究高血糖时的血管炎症是否：(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) 钙蛋白酶活性升高下调eNOS酶活性，导致NO生理性水平下降；(4) 钙蛋白酶的激活增加内皮细胞表面促炎症黏附的表达 通过上调核因子-ICB的活性。我们将利用以下体内和体外细胞 生理学技术：活体显微镜、静态和流动培养微血管内皮细胞 条件，体内和体外无测量，免疫组织化学，Western印迹分析和凝胶 移位化验。通过这些手段，本提案中的研究将阐明重要的和新颖的机制。 糖尿病潜在的微血管功能障碍。这些信息应该提供一个框架，以 开发新的治疗策略来治疗危及生命的疾病--糖尿病。

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.