Insulin Resistance in Chronic Kidney Disease

慢性肾脏疾病（CKD）影响多达2600万美国人，占美国人口的13%。中重度CKD（3-4期，定义为肾小球滤过率15-59 mL/min/1.73m2）对公共卫生的影响特别大，因为它最普遍，而且它可能会放大心血管疾病的风险。具体而言，中重度CKD患者具有心血管疾病的重要“非传统”风险因素，这些风险因素未通过针对一般人群开发的风险降低策略得到充分解决。胰岛素抵抗是CKD可能导致心血管疾病的一种“非传统”机制。在CKD中，由于独特的代谢异常，包括肾骨化三醇合成受损、代谢性酸中毒和尿毒症毒素蓄积，骨骼肌中对胰岛素作用的受体后抵抗通常是获得性的。反过来，胰岛素抵抗可能通过损害内皮功能、增加活性氧和加剧全身炎症而促进心血管疾病。CKD特有的代谢异常从根本上改变了病理生理学和胰岛素抵抗的确定，并为治疗干预提供了新的潜在靶点。这项资助申请的总体目标是全面描述中重度CKD患者的胰岛素抵抗。首先，我们建议使用金标准方法（高胰岛素正葡萄糖钳夹、静脉内葡萄糖耐量试验、口服葡萄糖耐量试验）来定义胰岛素抵抗的严重程度、胰腺β细胞的代偿反应以及对葡萄糖耐量的净影响，这些目前尚不清楚。其次，我们建议开发和验证公式估计胰岛素抵抗用于未来的流行病学研究和临床试验。第三，我们建议检测胰岛素抵抗与内皮功能、氧化应激和炎症的关系。为了实现这些目标，我们组建了一个多学科团队，拥有CKD生物学、代谢、胰岛素敏感性和β细胞功能定量评估、营养和生物统计学方面的专业知识。作为这种创新合作方法的一部分，本研究将利用华盛顿大学和西雅图肾脏研究所的现有资源。其中包括转化健康科学研究所临床研究中心，营养和身体成分核心，以及生物医学统计中心。

Chronic kidney disease (CKD) affects up to 26 million Americans, or 13% of the United States population. Moderate-severe CKD (stage 3-4, defined by glomerular filtration rate 15-59 mL/min/1.73m2) has a particularly large public health impact because it is most prevalent and because it potently amplifies risk of cardiovascular disease. Specifically, individuals with moderate-severe CKD have important "non-traditional" risk factors for cardiovascular disease which are not adequately addressed by risk reduction strategies developed for the general population. Insulin resistance is one "non-traditional" mechanism through which CKD may cause cardiovascular disease. In CKD, post-receptor resistance to insulin action in skeletal muscle is commonly acquired due to unique metabolic abnormalities, including impaired renal calcitriol synthesis, metabolic acidosis, and accumulation of uremic toxins. In turn, insulin resistance may promote cardiovascular disease by impairing endothelial function, increasing reactive oxygen species, and exacerbating systemic inflammation. The metabolic abnormalities unique to CKD fundamentally alter the pathophysiology and ascertainment of insulin resistance and offer novel potential targets for therapeutic intervention. The overall goal of this grant application is to comprehensively characterize insulin resistance in moderate- severe CKD. First, we propose to define the severity of insulin resistance, the compensatory response of the pancreatic beta cell, and net effects on glucose tolerance, which are currently poorly understood, using gold standard methods (hyperinsulinemic euglycemic clamp, intravenous glucose tolerance test, oral glucose tolerance test). Second, we propose to develop and validate formulae estimating insulin resistance for use in future epidemiologic studies and clinical trials. Third, we propose to test associations of insulin resistance with endothelial function, oxidative stress, and inflammation. To accomplish these goals, we have assembled a multidisciplinary team with expertise in the biology of CKD, metabolism, quantitative assessment of insulin sensitivity and beta-cell function, nutrition, and biostatistics. As part of this innovative collaborative approach, this study will take advantage of existing resources at the University of Washington and the Kidney Research Institute in Seattle. These include the Institute for Translational Health Sciences Clinical Research Center, Nutrition and Body Composition Core, and Center for Biomedical Statistics.