Insulin as a Regulator of Microvascular Exchange

描述（由申请人提供）：在诊断2型糖尿病（DM 2）之前，存在胰岛素抵抗（InsR）状态。虽然InsR的特征在于高血浆水平的胰岛素和葡萄糖，但在观察到的微血管功能障碍变化的病因学中最常研究的是高血糖症。独立于其在葡萄糖代谢中的作用，胰岛素可以改变内皮细胞（EC）的主要功能：交换。交换如何变化也取决于性别。具体而言，急性高胰岛素（10-7 M，Ins+）仅在男性中增加微血管对蛋白质的通透性（Ps）。此外，EC从男性和女性保留在文化中的振荡生殖激素和急性（分钟）和慢性（周）暴露于胰岛素elections的情况下的性别差异，在EC信号的性别依赖性和非依赖性的变化。这些数据导致了新假设的形成，将在3个目标中进行测试，即胰岛素， 一种基因组的、性别依赖的方式，通过调节微血管对蛋白质的渗透性（Ps）来促进体液平衡。因此，将使用定量体内和体外方法评估两种性别成年大鼠中的Psalbumin，以确定在目标1中原位微血管交换调节中急性胰岛素的性别依赖性，此时Ins+预计会改变雄性而非雌性大鼠中的急性（分钟-小时）蛋白通量。目的2：胰岛素作用的性别差异是否 将确定在慢性高胰岛素血症（Ins+，在InsR和DM 2中不存在混杂因素的情况下）期间Psalbumin加重。预计慢性胰岛素会导致间质环境的潜在变化，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相对于NO和内皮素-1（ET-1）水平的EC表型的变化。最后，在目标3中，为了完成垂直整合，将分别使用培养的雄性和雌性微血管EC来确定哪些EC胰岛素受体介导的信号传导机制是性别特异性的。假设响应于胰岛素的EC表型反映EC-胰岛素信号传导途径的贡献中的M/F差异，分别导致内皮素（ET-1）和一氧化氮（NO）产生。DM 2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）对急性和慢性胰岛素的性别特异性基因组EC应答，以及c）介导这些应答的细胞Ins信号传导将有助于制定用于早期疾病识别和定制患者治疗的策略，以改善（如果不是逆转的话）或阻止疾病进展。

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.