Endothelial Insulin Resistance, Inflammation and Vascular Function in Diabetes

描述(申请人提供)：糖尿病患者的心血管疾病是一个紧迫的临床问题。血管内皮细胞对维持血管内环境平衡至关重要。内皮细胞表型的改变导致一氧化氮生物活性丧失，并通过核因子B增强内皮炎性激活，可能参与糖尿病动脉粥样硬化的形成和临床血管事件。最近的实验研究表明，胰岛素信号通过PI3K-Akt途径参与内皮一氧化氮的产生。在动物模型中，这些信号机制的异常会导致内皮胰岛素抵抗并损害血管功能。PKC2的激活可能将糖尿病的代谢紊乱与内皮细胞胰岛素抵抗和促炎内皮细胞表型联系起来。尽管内皮细胞表型改变可能与临床相关，但很少有研究将这些实验结果转化为糖尿病患者。我们的初步数据表明，使用一种新的方法从受试者中收集和表征内皮细胞，内皮炎性激活与血管功能障碍和糖尿病有关。我们现在建议检验这一假说，即内皮细胞表型改变有助于糖尿病患者的血管功能障碍。在目标1中，我们将描述血管内皮细胞胰岛素抵抗和炎症激活与血管功能障碍和糖尿病的关系。我们将在120例糖尿病患者和120例对照组中，将内皮胰岛素信号转导标志(eNOS表达，胰岛素介导的eNOS磷酸化)和内皮炎症激活的证据(I：2，P65，ICAM表达)与糖尿病的存在以及内皮血管运动功能障碍(血流介导的扩张，外周动脉测压和反应性充血)的严重程度相关联。在目标2中，我们将研究PKC2的激活和NF：2的激活在不良的内皮表型和血管功能受损中的作用。我们假设，选择性PKC2抑制剂(LY379196)或核因子：2抑制剂(水杨酸钠)体外治疗将逆转内皮细胞胰岛素抵抗和炎症激活，支持糖尿病患者炎症和PKC2激活的作用。在目标3中，我们将通过评估使用安慰剂或抗炎药物水杨酸盐(一种核因子：2激活的抑制剂)治疗前后的血管功能和内皮表型，获得血管内皮细胞表型改变导致40名糖尿病患者一氧化氮生物利用度受损的证据。我们希望这些研究将提高我们对糖尿病血管疾病发病机制的理解，这将与创新的治疗和预防疗法的产生相关。

DESCRIPTION (provided by applicant): Cardiovascular disease in patients with diabetes is a pressing clinical problem. The endothelium is vital to the maintenance of vascular homeostasis. Alteration of endothelial cell phenotype leading to loss of nitric oxide bioactivity and increased endothelial inflammatory activation via NF:B may contribute to atherogenesis and clinical vascular events in diabetes. Recent experimental studies indicate that insulin signaling through the PI3K-Akt pathway contributes to endothelial nitric oxide production. Abnormalities of these signaling mechanisms produce endothelial insulin resistance and impair vascular function in animal models. Activation of PKC2 may link the metabolic derangements of diabetes to endothelial insulin resistance and pro-inflammatory endothelial phenotype. Despite the potential clinical relevance of altered endothelial phenotype, few studies have translated these experimental findings to patients with diabetes. Our preliminary data show that endothelial inflammatory activation is associated with vascular dysfunction and diabetes using a novel method to collect and characterize endothelial cells from human subjects. We now propose to test the hypothesis that altered endothelial cell phenotype contributes to vascular dysfunction in patients with diabetes. In Aim 1, we will characterize the relation of endothelial cell insulin resistance and inflammatory activation to vascular dysfunction and diabetes mellitus in human subjects. We will relate markers of endothelial insulin signaling (eNOS expression, insulin-mediated eNOS phosphorylation) and evidence of endothelial inflammatory activation (I:2, p65, ICAM expression) in endothelial cells freshly isolated from human subjects to the presence of diabetes and to the severity of endothelial vasomotor dysfunction (flow-mediated dilation, peripheral arterial tonometry and reactive hyperemia) in 120 patients with diabetes and 120 control subjects. In Aim 2, we will investigate the contribution of PKC2 activation and NF:2 activation to adverse endothelial phenotype and impaired vascular function. We hypothesize that endothelial cell insulin resistance and inflammatory activation will be reversed with in vitro treatment with selective PKC2 inhibitor (LY379196) or an NF:2 inhibitor (sodium salicylate), supporting a role for inflammation and PKC2 activation in patients with diabetes. In Aim 3, we will gain evidence that altered endothelial cell phenotype contributes to impaired nitric oxide bioavailability in 40 patients with diabetes by assessing vascular function and endothelial phenotype before and after treatment with placebo or the anti-inflammatory drug salsalate, an inhibitor of NF:2 activation. We expect that these studies will improve our understanding of the pathogenesis of vascular disease in diabetes that will be relevant to the generation of innovative therapeutic and preventive therapies.