Department of Kinesiology, University of Virginia, Charlottesville, Virginia.
Division of Cardiology, Pauley Heart Center, Virginia Commonwealth University, Richmond, Virginia.
Am J Physiol Heart Circ Physiol. 2021 Jun 1;320(6):H2305-H2312. doi: 10.1152/ajpheart.00975.2020. Epub 2021 Apr 16.
Adults with metabolic syndrome (MetS) have increased fasting arterial stiffness and altered central hemodynamics that contribute, partly, to increased cardiovascular disease (CVD) risk. Although insulin affects aortic wave reflections in healthy adults, the effects in individuals with MetS are unclear. We hypothesized that insulin stimulation would reduce measures of pressure waveforms and hemodynamics in people with MetS. Thirty-five adults with obesity (27 women; 54.2 ± 6.0 yr; 37.1 ± 4.8 kg/m) were selected for MetS (ATP III criteria) following an overnight fast. Pulse wave analysis was assessed using applanation tonometry before and after a 2-h euglycemic-hyperinsulinemic clamp (90 mg/dL, 40 mU/m/min). Deconvolution analysis was used to decompose the aortic waveform [augmentation index corrected to heart rate of 75 beats/min (AIx@75); augmentation pressure (AP)] into backward and forward pressure components. Aerobic fitness (V̇o), body composition (DXA), and blood biochemistries were also assessed. Insulin significantly reduced augmentation index (AIx@75, 28.0 ± 9.6 vs. 23.0 ± 9.9%, < 0.01), augmentation pressure (14.8 ± 6.4 vs. 12.0 ± 5.7 mmHg, < 0.01), pulse pressure amplification (1.26 ± 0.01 vs. 0.03 ± 0.01, = 0.01), and inflammation [high-sensitivity C-reactive protein (hsCRP): = 0.02; matrix metallopeptidase 7 (MMP-7): = 0.03] compared to fasting. In subgroup analyses to understand HTN influence, there were no insulin stimulation differences on any outcome. V̇o, visceral fat, and blood potassium correlated with fasting AIx@75 ( = -0.39, = 0.02; = 0.41, = 0.03; = -0.53, = 0.002). Potassium levels were also associated with insulin-mediated reductions in AP ( = 0.52, = 0.002). Our results suggest insulin stimulation improves indices of aortic reflection in adults with MetS. This study is one of the first to investigate the effects of insulin on central and peripheral hemodynamics in adults with metabolic syndrome. We provide evidence that insulin infusion reduces aortic wave reflection, potentially through a reduction in inflammation and/or via a potassium-mediated vascular response.
患有代谢综合征 (MetS) 的成年人空腹时动脉僵硬度增加，且中心血液动力学发生改变，这部分导致其心血管疾病 (CVD) 风险增加。尽管胰岛素会影响健康成年人的主动脉波反射，但在 MetS 患者中的影响尚不清楚。我们假设胰岛素刺激会降低 MetS 患者的压力波和血液动力学测量值。在禁食过夜后，根据 ATP III 标准选择 35 名肥胖成年人（27 名女性；54.2±6.0 岁；37.1±4.8kg/m）患有 MetS。使用平板张力测量法在 2 小时的正常血糖高胰岛素钳夹（90mg/dL，40mU/m/min）前后评估脉搏波分析。去卷积分析用于将主动脉波形[心率为 75 次/分时的增强指数校正（AIx@75）；增强压（AP）]分解为向后和向前压力分量。还评估了有氧运动能力（V̇o）、身体成分（DXA）和血液生化指标。胰岛素显著降低了增强指数（AIx@75，28.0±9.6%对 23.0±9.9%， ＜0.01）、增强压（14.8±6.4mmHg 对 12.0±5.7mmHg， ＜0.01）、脉搏压放大率（1.26±0.01 对 0.03±0.01， ＝0.01）和炎症[高敏 C 反应蛋白（hsCRP）： ＝0.02；基质金属蛋白酶 7（MMP-7）： ＝0.03]与空腹相比。在理解 HTN 影响的亚组分析中，胰岛素刺激对任何结果均无差异。V̇o、内脏脂肪和血钾与空腹 AIx@75 相关（ ＝-0.39， ＝0.02； ＝0.41， ＝0.03； ＝-0.53， ＝0.002）。钾水平也与胰岛素介导的 AP 降低相关（ ＝0.52， ＝0.002）。我们的结果表明，胰岛素刺激可改善 MetS 成年人的主动脉反射指数。这项研究是首次在代谢综合征成年人中研究胰岛素对中心和外周血液动力学的影响的研究之一。我们提供的证据表明，胰岛素输注可降低主动脉波反射，这可能是通过降低炎症和/或通过钾介导的血管反应实现的。
