Department of Medicine, Division of Endocrinology and Institute for Translational Science; University of Texas Medical Branch at Galveston, Texas;
Am J Physiol Endocrinol Metab. 2013 Oct 15;305(8):E999-E1006. doi: 10.1152/ajpendo.00194.2013. Epub 2013 Aug 27.
The purpose of this study was to evaluate the variability of subcutaneous abdominal adipose tissue (AT) dynamics in obese subjects with a wide range of insulin sensitivity (IS) and the correlation between these two metabolic measures. Ten obese (BMI 30-40 kg/m²) nondiabetic subjects with (n = 6) and without (n = 4) the metabolic syndrome were studied following a 12-wk ²H₂O labeling period. Subcutaneous abdominal AT biopsies were collected. Deuterium incorporation into triglyceride (TG)-glycerol and TG-palmitate were measured by gas chromatography-mass spectrometry for the calculation of fractional TG synthesis (fTG) and fractional de novo lipogenesis (fDNL). Muscle IS and insulin-mediated nonesterified fatty acid (NEFA) suppression (a measure for adipose IS) indexes were derived from the oral glucose tolerance test (OGTT). The ability of subcutaneous abdominal AT to synthesize lipids varied significantly in obese subjects (fTG range 7-28%, fDNL range 1.1-4.6%) with significantly lower values (>35% reduction) for both parameters in obese with the metabolic syndrome. fTG correlated positively with muscle IS (r = 0.64, P = 0.04) and inversely with NEFA suppression during the OGTT (r = -0.69, P = 0.03). These results demonstrate a large variability in subcutaneous abdominal AT lipid turnover in obesity. Moreover, a reduced capacity for subcutaneous abdominal AT fat storage is associated with muscle and adipose tissue insulin resistance as well as with the metabolic syndrome, thus identifying a form of obesity at heightened risk for type 2 diabetes and cardiovascular disease.
这项研究的目的是评估胰岛素敏感性（IS）范围广泛的肥胖患者皮下腹部脂肪组织（AT）动态的变异性，以及这两种代谢测量之间的相关性。在 12 周的 ²H₂O 标记期后，研究了 10 名肥胖（BMI 30-40 kg/m²）的非糖尿病患者（n = 6）和无代谢综合征的患者（n = 4）。收集皮下腹部 AT 活检。通过气相色谱-质谱法测量甘油三酯（TG）-甘油和 TG-棕榈酸中的氘掺入，以计算甘油三酯合成的分数（fTG）和从头脂肪生成的分数（fDNL）。口服葡萄糖耐量试验（OGTT）得出肌肉 IS 和胰岛素介导的非酯化脂肪酸（NEFA）抑制（衡量脂肪 IS 的指标）指数。肥胖患者的皮下腹部 AT 合成脂质的能力差异很大（fTG 范围为 7-28%，fDNL 范围为 1.1-4.6%），代谢综合征肥胖患者的这两个参数的降低值均超过 35%（减少 35%以上）。fTG 与肌肉 IS 呈正相关（r = 0.64，P = 0.04），与 OGTT 期间的 NEFA 抑制呈负相关（r = -0.69，P = 0.03）。这些结果表明肥胖症患者皮下腹部 AT 脂质周转的变异性很大。此外，皮下腹部 AT 脂肪储存能力降低与肌肉和脂肪组织胰岛素抵抗以及代谢综合征有关，从而确定了一种肥胖症，其患 2 型糖尿病和心血管疾病的风险更高。
