目的:与非西班牙裔白人女性(WW)相比,非西班牙裔黑人女性(BW)患2型糖尿病(T2D)和胰岛素抵抗(IR)的风险更大。导致这些差异的机制尚不清楚,目前尚不清楚种族和肥胖的协同作用是否会影响疾病风险。为了理解种族和体重的相互作用,比较了有和没有肥胖的WW和BW的肝脏和外周IR。
方法:通过标记,高胰岛素-正常血糖钳夹在有和没有肥胖的BW(n=32)和WW(n=32)中。身体成分的测量,心肺健康,骨骼肌(SM)呼吸完成。通过混合模型ANOVA分析数据。
结果:肥胖受试者的肝脏和外周IR较高,SM呼吸较低(P<0.001)。尽管胰岛素增加了14%(P=0.066),BW倾向于有较低的外周葡萄糖处置(Rd;P=0.062),这是由没有肥胖的女性驱动的(P=0.002)。BW具有显著降低的葡萄糖产生(P=0.005),肝IR(P=0.024),最大耦合和非耦合呼吸(P<0.001)比WW。最大耦合和非耦合SM线粒体呼吸与外周和肝脏IR密切相关(P<0.01)。
结论:虽然没有肥胖的BW的Rd低于WW,种族和肥胖没有协同影响外周IR。矛盾的是,与BW相比,肥胖的WW具有更大的肝脏IR。SM呼吸和IR之间的关系在整个体重范围内持续存在。这些数据为BW的治疗提供了支持,像锻炼一样,改善SM线粒体呼吸,降低IR和T2D风险。
OBJECTIVE: Non-Hispanic black women (BW) have a greater risk of type 2 diabetes (T2D) and insulin resistance (IR) compared to non-Hispanic white women (WW). The mechanisms leading to these differences are not understood, and it is unclear whether synergistic effects of race and obesity impact disease risk. To understand the interaction of race and weight, hepatic and peripheral IR were compared in WW and BW with and without obesity.
METHODS: Hepatic and peripheral IR was measured by a labeled, hyperinsulinemic-euglycemic clamp in BW (n=32) and WW (n=32) with and without obesity. Measurements of body composition, cardiorespiratory fitness, and skeletal muscle (SM) respiration were completed. Data were analyzed by mixed model ANOVA.
RESULTS: Subjects with obesity had greater hepatic and peripheral IR and lower SM respiration (P<0.001). Despite 14% greater insulin (P=0.066), BW tended to have lower peripheral glucose disposal (Rd; P=0.062), which was driven by women without obesity (P=0.002). BW had significantly lower glucose production (P=0.005), hepatic IR (P=0.024), and maximal coupled and uncoupled respiration (P<0.001) than WW. Maximal coupled and uncoupled SM mitochondrial respiration was strongly correlated with peripheral and hepatic IR (P<0.01).
CONCLUSIONS: While BW without obesity had lower Rd than WW, race and obesity did not synergistically impact peripheral IR. Paradoxically, WW with obesity had greater hepatic IR compared to BW. Relationships between SM respiration and IR persisted across a range of body weight. These data provide support for therapies in BW, like exercise, that improve SM mitochondrial respiration to reduce IR and T2D risk.