Department of Biochemistry and Molecular Biology, Soochow University Medical College, Suzhou, China; Center for Human Nutrition, Washington University School of Medicine, St. Louis, Missouri, USA.
Obesity (Silver Spring). 2015 Feb;23(2):329-34. doi: 10.1002/oby.20923. Epub 2014 Oct 18.
An increase in circulating branched-chain amino acids (BCAA) is associated with insulin resistance. Adipose tissue is a potentially important site for BCAA metabolism. It was evaluated whether monomethyl branched-chain fatty acids (mmBCFA) in adipose tissue, which are likely derived from BCAA catabolism, are associated with insulin sensitivity.
Insulin-stimulated glucose disposal was determined by using the hyperinsulinemic-euglycemic clamp procedure with stable isotope glucose tracer infusion in nine lean and nine obese subjects, and in a separate group of nine obese subjects before and 1 year after Roux-en-Y gastric bypass (RYGB) surgery (38% weight loss). Adipose tissue mmBCFA content was measured in tissue biopsies taken in the basal state.
Total adipose tissue mmBCFA content was ∼30% lower in obese than lean subjects (P=0.02) and increased by ∼65% after weight loss in the RYGB group (P=0.01). Adipose tissue mmBCFA content correlated positively with skeletal muscle insulin sensitivity (R(2) =35%, P=0.01, n=18).
These results demonstrate a novel association between adipose tissue mmBCFA content and obesity-related insulin resistance. Additional studies are needed to determine whether the association between adipose tissue mmBCFA and muscle insulin sensitivity is causal or a simple association.
循环支链氨基酸（BCAA）的增加与胰岛素抵抗有关。脂肪组织是 BCAA 代谢的一个潜在重要部位。本研究评估了脂肪组织中可能来源于 BCAA 分解代谢的单甲基支链脂肪酸（mmBCFA）是否与胰岛素敏感性相关。
在 9 名瘦人和 9 名肥胖者中，以及在 Roux-en-Y 胃旁路（RYGB）手术（体重减轻 38%）前和 1 年后的 9 名肥胖者中，通过使用稳定同位素葡萄糖示踪剂输注的高胰岛素-正葡萄糖钳夹程序，测定胰岛素刺激的葡萄糖处置情况。在基础状态下，从脂肪组织活检中测量脂肪组织 mmBCFA 含量。
肥胖者的总脂肪组织 mmBCFA 含量比瘦者低约 30%（P=0.02），而 RYGB 组在减重后增加了约 65%（P=0.01）。脂肪组织 mmBCFA 含量与骨骼肌胰岛素敏感性呈正相关（R²=35%，P=0.01，n=18）。
这些结果表明脂肪组织 mmBCFA 含量与肥胖相关的胰岛素抵抗之间存在新的关联。需要进一步研究以确定脂肪组织 mmBCFA 与肌肉胰岛素敏感性之间的关联是因果关系还是简单的关联。
