Study of the effects of transoral gastroplasty on insulin sensitivity and secretion in obese subjects

Transoral gastroplasty (TOGA) recently emerged as a new, feasible and relatively safe technique for the surgical treatment of obesity. However, so far there are no data on the effects on insulin sensitivity in the literature. Our aim is to evaluate the effect of TOGA on insulin sensitivity and secretion.Nine glucose normo-tolerant obese subjects (age:41+/-6 years; BMI:42.49+/-1.03 kg/m(2)) were studied. Fat-free mass (FM) and fat mass (FM) were assessed by bioelectrical impedance; plasma glucose, insulin, and C-peptide were measured during an oral glucose tolerance test (OGTT) before and 3 months after the operation. Insulin sensitivity was calculated using the oral-glucose insulin-sensitivity index, and insulin secretion by C-peptide deconvolution. Three months after surgery, a significant (P=0.008) reduction of BMI to 35.65+/-0.65 kg/m(2), with a decrease of FM and FFM from 57.22+/-2.19 to 41.46+/-3.02 kg (P=0.008) and from 59.52+/-1.36 to 56.67+/-1.10 kg (P=0.048) respectively, was observed. Insulinemia was significantly reduced at fast and at 120 min after OGTT; in contrast, no significant change in glucose concentration was observed. Insulin sensitivity significantly increased (348.45+/-20.08 vs. 421.18+/-20.84 ml/min/m(2), P=0.038) and the incremental area of insulin secretion rate (total ISR) significantly decreased (from 235.05+/-27.50 to 124.77+/-14.50 nmol/min/m(2), P=0.021). Total ISR correlated with weight, BMI and FM (r=0.522, P=0.028; r=0.541, P=0.020; r=0.463, P=0.049, respectively). BMI represented the most powerful predictor of ISR decrease (R(2)=0.541, P=0.020).Transoral gastroplasty allows a significant weight loss 3 months after the intervention as well as an amelioration of insulin sensitivity with subsequent reduction of the insulin secretion.