Abstract 8543: Ectopic Fat Mobilization Following a Bariatric Surgery-Induced Weight Loss; Association with Insulin Resistance

Abstract

Severe obesity is associated with increased cardiovascular morbidity and mortality and is increasing in prevalence. The purpose of the study was to measure the impact of weight loss and changes in insulin resistance following biliopancreatic diversion with duodenal switch (BPD-DS) procedure on adiposity and skeletal muscle. Anthropometric measures, mid-thigh computed tomography (CT) and fasting plasma glucose and insulin were measured at baseline, at 6 and 12 months in severely obese subjects who underwent BPD-DS (n=43) and in a severely obese control group (n=24). At baseline, the two groups were similar for age, sex, weight (128.3±23.3 vs. 117.6±19.1 kg; p=0.059, BPD-DS vs. control respectively) and mid-thigh CT composition but not for body mass index (BMI) (47.6±5.9 vs. 43.5±4.8 kg/m2; p=0.004). At 6 months, in the BPD-DS group, there were a significant decrement in weight (-26.7±7.4%), BMI (-26.7±5.6%), as well as in mid-thigh CT composition: total adipose tissue (-34.7±10.5%), deep adipose tissue (-36.1±15.4%), subcutaneous adipose tissue (-34.7±10.5%), total skeletal muscle (-19.2±8.8%), fat infiltrated muscle (-54.4±29.4%) and non-fat infiltrated muscle (-17.7±11.4%); all p<0.001. Between month 6 and 12, in the BDP-DS group, weight, BMI, total, deep and subcutaneous adipose tissue decrease significantly but to a lesser degree compared to the first 6 month; all p≤0.001. There was no change regarding total skeletal muscle, but a significant increment in non-fat infiltrated muscle (5.3±7.8%) and decrement in fat infiltrated muscle (-11.8±10.8%); all p≤0.001. A decreased in insulin resistance at 6 and 12 months was associated with a reduction of thigh deep adipose tissue (r=0.469, r=0.692, 6 and 12 months respectively) and fat infiltrated muscle (r=0.469, r=0.526); all p≤0.001. There were no changes, in all these parameters in the control group. BPD-DS surgery-induced weight loss had major impact on muscle and fat mass. Mobilization of thigh ectopic fat; thigh deep adipose tissue and fat-infiltrated muscle, may be one mechanism that improves insulin resistance. Muscle regain at 12 months suggests that BPD-DS exerts a physiologic effect beyond that of nutrient restriction on the regulation of energy metabolism.