The role of visceral adipose tissue on improvement in insulin sensitivity following Roux-en-Y gastric bypass: a study in Chinese diabetic patients with mild and central obesity

BACKGROUND: Most Chinese patients with type 2 diabetes mellitus (T2DM) have mild obesity and central obesity. Central obesity is combined with insulin resistance. The aim of this study was to assess the effect of abdominal adipose tissue on insulin-sensitivity improvement after Roux-en-Y gastric bypass (RYGB) in Chinese diabetic patients with mild and central obesity. METHODS: Seventeen T2DM patients with a mean body mass index of 30.3 kg/m(2) were scheduled for laparoscopic RYGB. A hyperinsulinemic-euglycemic clamp and dual-energy X-ray absorptiometry were performed prior to surgery and 3 months after RYGB. The primary end points were the correlations between insulin sensitivity and abdominal adipose tissue, including visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT), before and 3 months after RYGB. RESULTS: Indices of peripheral insulin sensitivity, including glucose-disposal rate (M value) and glucose infusion rate, were significantly increased after RYGB. Body-fat mass, VAT and SAT were significantly reduced after RYGB. The pre-operative M value was significantly correlated with VAT mass (r = –0.57, P = 0.02), but not correlated with SAT mass. M value changes after RYGB were highly correlated with changes in VAT mass (r = –0.59, P = 0.01), percentage of VAT mass (r = –0.66, P < 0.01), VAT area (r = –0.56, P = 0.02) and percentage of VAT area (r = –0.57, P = 0.02). CONCLUSIONS: A significant correlation was observed between increased peripheral insulin sensitivity and decreased VAT following RYGB in Chinese patients with mild and central obesity. VAT and SAT were significantly decreased with improved insulin sensitivity after RYGB. VAT mass may be considered as an indication for gastric bypass during patient selection.