Insulin as a Regulator of Microvascular Exchange

描述(由申请人提供)：在诊断2型糖尿病(DM2)之前，存在胰岛素抵抗(InsR)状态。虽然InsR以高胰岛素和高血糖水平为特征，但在观察到的微血管功能障碍的病因学中，最常被研究的是高血糖。与其在葡萄糖代谢中的作用无关，胰岛素可以改变主要的内皮细胞(EC)功能：交换。交换的变化也取决于性别。具体地说，急性高胰岛素(10-7M，Ins+)只在男性中增加蛋白质的微血管通透性(Ps)。此外，在没有振荡生殖激素的情况下，来自男性和女性的EC在培养中保留了性别差异，并且急性(分钟)和长期(每周)暴露于胰岛素会引起EC信号的性别依赖性和非独立性变化。这些数据导致了这一新假说的形成，该假说将在三个目标中进行检验，即胰岛素、 基因组，性别依赖的方式，有助于通过调节微血管通透性(Ps)到蛋白质的液体平衡。因此，将使用体内和体外定量方法评估成年大鼠的Psalb，以确定在Aim 1中急性胰岛素在调节原位微血管交换中的性别依赖性，当Ins+被预测在雄性而不是雌性中急剧改变蛋白质流量(min-hrs)时。在目标2中是否存在性别差异对胰岛素的作用 在慢性高胰岛素血症(INS+，在InsR和DM2中不存在混杂因素的情况下)将被确定。慢性胰岛素被认为会导致间质环境的潜伏性变化，表现为蛋白酶活性的变化，组织蛋白和炎症介质的升高，以及与NO和内皮素-1(ET-1)水平相关的EC表型的变化。最后，在目标3中，为了完善垂直整合，将分别使用男性和女性培养的微血管EC来确定哪些EC胰岛素受体介导的信号机制是性别特异性的。EC对胰岛素反应的表型被认为反映了EC-胰岛素信号通路在导致内皮素(ET-1)和一氧化氮(NO)产生方面的M/F差异。DM2是一种慢性进行性疾病，女性的发病率和死亡率高于男性，尽管发病率与性别无关。了解a)INS+在屏障功能丧失中的直接作用，b)性别特异性的基因组EC对急性和慢性胰岛素的反应，以及c)介导这些反应的细胞INS信号将有助于制定早期疾病识别和患者治疗的策略，以改善(如果不是逆转)或阻止疾病的进展。

DESCRIPTION (provided by applicant): Prior to diagnosis of type 2 diabetes (DM2) the state of insulin resistance (InsR) exists. While InsR is characterized by high plasma levels of insulin and glucose, it is hyperglycemia that is most often studied in the etiology of observed changes in microvascular dysfunction. Independent of its role in glucose metabolism insulin can alter the major endothelial cell (EC) function: exchange. How exchange changes also depends on sex. Specifically, acute high insulin (10-7 M, Ins+) increases microvascular permeability (Ps) to protein only in males. Further, EC from males and females retain sex differences in culture in the absence of oscillating reproductive hormones and acute (min) and chronic (weeks) exposure to insulin elicits both sex-dependent and -independent changes in EC signaling. These data lead to the formulation of the novel hypothesis, to be tested in 3 aims that insulin, in a genomic, sex-dependent manner, contributes to fluid balance via regulation of microvessel permeability (Ps) to proteins. Thus, Psalbumin in adult rats of both sexes will be assessed using quantitative in vivo and in vitro methods to determine the sex-dependence of acute insulin in the regulation of in situ microvascular exchange in Aim 1, when Ins+ is predicted to alter acutely (min-hrs) protein flux in males, not females. In Aim 2 whether sex differences in insulin action on Psalbumin are exacerbated during chronic hyperinsulinemia (Ins+, in the absence of confounding factors present in InsR and DM2) will be determined. Chronic insulin is predicted to lead to insidious changes in interstitial milieu manifested as changes in protease activity, elevated tissue protein and inflammatory mediators, and changes in EC phenotype with respect to levels of NO and endothelin-1 (ET-1). Finally, in Aim 3, to round out the vertical integration, cultured microvessel EC of males and females, respectively, will be used to determine which EC insulin receptor-mediated signaling mechanisms are sex-specific. The EC phenotype in response to insulin is posited to reflect M/F-differences in the contribution of the EC- insulin signaling pathways leading to endothelin (ET-1) and nitric oxide (NO) production, respectively. DM2 is a chronic progressive disease with a greater morbidity and mortality in women than men albeit the incidence is sex-independent. Knowledge of a) the direct role of Ins+ in loss of barrier function, b) the sex-specific, genomic EC responses to acute and chronic insulin, and c) the cellular Ins signaling mediating these responses will facilitate formulation of strategies for earler disease identification and tailoring of patient therapy to ameliorate, if not reverse, or stop disease progression.