Race - adiposity interactions regulate mechanisms determining insulin sensitivity

种族-肥胖相互作用调节决定胰岛素敏感性的机制

• 批准号: 8504840
• 负责人: BARBARA A GOWER
• 金额: $ 56.68万
• 依托单位: UNIVERSITY OF ALABAMA AT BIRMINGHAM
• 依托单位国家: 美国
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-09-19 至 2018-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8504840
• 关键词: Admixture; Adult; African; African American; American; Bioenergetics; Blood Pressure; Blood Vessels; Body mass index; Cardiovascular Diseases; Cardiovascular Physiology; Cardiovascular system; Chronic; Coupled; Coupling; Data; Development; Diabetes Mellitus; Dyslipidemias; Electron Transport; Endothelial Cells; Ethnic Origin; Etiology; Euglycemic Clamping; European; Fatty acid glycerol esters; Functional disorder; Genetic; Genotype; Glucose; Glucose Clamp; Hepatic; Hydrogen Peroxide; Impairment; In Vitro; Individual; Insulin; Insulin Resistance; Label; Leptin; Lipids; Literature; Magnetic Resonance Imaging; Malignant Neoplasms; Measures; Mediating; Metabolic; Metabolic Diseases; Methods; Muscle Fibers; Muscle Mitochondria; National Institute of Diabetes and Digestive and Kidney Diseases; Natural History; Non-Insulin-Dependent Diabetes Mellitus; Obesity; Outcome; Overweight; Oxidative Phosphorylation; Oxidative Stress; Participant; Patient Self-Report; Patients; Physiological; Play; Prevention; Production; Race; Reactive Oxygen Species; Reference Standards; Relative (related person); Research; Research Priority; Risk; Role; Secondary to; Serum amyloid A protein; Skeletal Muscle; Specific qualifier value; Strategic Planning; TNF gene; Testing; Tracer; Visceral; Woman; adipokines; adiponectin; base; blood glucose regulation; cytokine; ethnic difference; fasting glucose; glucose disposal; glucose production; insulin sensitivity; insulin sensitivity/resistance; named group; public health relevance; racial and ethnic disparities; treatment strategy

DESCRIPTION (provided by applicant): Project summary. Insulin resistance plays a major role in the etiology of chronic metabolic diseases, many of which differ with race/ethnicity. Previous studies using mainly indirect methods suggest that insulin sensitivity is lower in African-Americans (AA) vs. European-Americans (EA). However, results are discrepant, differing with the method used and the obesity status of the participants. Our preliminary data using the reference standard glucose clamp indicate that in lean individuals, insulin sensitivity i lower among AA, while in obese individuals, insulin sensitivity is higher among AA. We hypothesize that this race/body mass index (BMI) interaction may be explained in part by significantly lower visceral/hepatic adiposity in AA that results in less impairment of insulin sensitivity among obese AA individuals. Conversely, we hypothesize that inherently greater oxidative stress impairs insulin sensitivity in AA, explaining lower insulin sensitivity in lean AA vs. EA. This is based on our preliminary data indicating that a circulating marker of cumulative oxidative stress was significantly associated with insulin-stimulated glucose disposal in AA but not EA, and that production of reactive oxygen species (ROS) in vitro was greater in AA vs. EA. We propose to test these hypotheses by prospectively comparing skeletal muscle and hepatic insulin sensitivity in healthy lean, overweight, and obese AA and EA using the hyperinsulinemic isoglycemic glucose clamp with tracer-labeled glucose. Analysis of ancestral genetic admixture will permit simultaneous assessment of the contribution of ancestry to main outcomes. With our first aim, we will test the hypothesis that a significant race-by-BMI interaction will be detected n skeletal muscle and hepatic insulin sensitivity, such that at low BMI AA are less insulin sensitive but at high BMI AA are more insulin sensitive, when compared with EA. The second aim will test the hypothesis that at high BMI, AA will have greater hepatic and skeletal muscle insulin sensitivity due to lower hepatic and visceral fat. The third aim will test the hypothesis that greater bioenergetic efficiency and ROS production within skeletal muscle mitochondria will be associated with lower skeletal muscle insulin sensitivity in lean AA. A secondary aim will test the hypothesis that skeletal muscle and hepatic insulin sensitivity are better associated with adipokines, cytokines, lipids, blood pressure, and vascular function in EA than in AA. Relevance. Results from this study elucidating why the underlying pathophysiology of insulin resistance differs with genetic background may guide development of personalized treatment strategies with implications for several chronic metabolic diseases (e.g., type 2 diabetes, cardiovascular disease, and cancer).

描述（由申请人提供）：项目概述。胰岛素抵抗在慢性代谢性疾病的病因学中起着重要作用，其中许多疾病因种族/民族而异。先前主要采用间接方法的研究表明，非裔美国人（AA）的胰岛素敏感性低于欧裔美国人（EA）。然而，结果是不一致的，不同的方法和参与者的肥胖状况。我们使用参考标准葡萄糖钳的初步数据表明，在瘦人中，AA的胰岛素敏感性较低，而在肥胖人群中，AA的胰岛素敏感性较高。我们假设，这种种族/体重指数（BMI）的相互作用可以部分解释为AA中内脏/肝脏脂肪明显较低，导致肥胖AA个体胰岛素敏感性受损较少。相反，我们假设固有的更大的氧化应激损害了AA的胰岛素敏感性，解释了瘦AA的胰岛素敏感性较低