[Effects of laparoscopic sleeve gastrectomy on insulin secretion patterns in morbidly obese patients]

To assess the effects of laparoscopic sleeve gastrectomy (LSG) on insulin secretion mode and metabolism of glucose and lipid in morbidly obese patients.

Clinical data of 65 morbidly obese patients [body mass index (BMI) ≥30 kg/m²] undergoing LSG at Shanghai 10th People's Hospital from August 2012 to December 2016 were retrospectively analyzed. According to the result of OGTT, these obese patients were divided into three groups: normal glucose tolerance (NGT, 23 cases), impaired glucose tolerance (IGT, 22 cases) and type 2 diabetes mellitus (DM, 20 cases) groups. Twenty-two healthy people [BMI (23.1±1.4) kg/m²] were used as control group. The anthropometries parameters [weight, BMI, waist circumference, body fat percentage, excess weight loss(%EWL)], glucose metabolic indices [fasting plasma glucose (FPG), fasting insulin (FINS), glycosylated hemoglobin (HbA1c), homeostasis model assessment-insulin resistance index (HOMA-IR)], lipid profile (TC, TG, HDL-C, LDL-C) and inflammatory factor (UA, TNF-α) of 3 groups were detected before operation and at postoperative 1-, 3-, 6-month. These variables were analyzed among morbidly obese groups before and after surgery and compared to control group. Clinical registration number of this study was ChiCTROCSl2002381.

Body weight, waist circumference and BMI of morbidly obese patients all decreased at postoperative 1-, 3-, 6-month. Postoperative %EWL increased obviously to (71.5±24.7)% with the highest range in DM group. Percentage of successful weight loss (%EWL>50%) in NGT, IGT and DM groups was 63.6%, 83.9% and 90.0% at postoperative 6-month respectively, and DM group was also the highest. At postoperative 6-month, HbA1c of 3 morbidly obese groups became normal; FPG and postprandial 2-hour glucose of IGT and DM group decreased to normal level; insulin level of 3 morbidly obese groups decreased obviously compared to pre-operation (all P<0.05), especially FINS and postprandial 2-hour insulin became normal without significant difference of control group (P>0.05), while postprandial 30-minute and 60-minute insulin levels in 3 groups were still higher as compared to control group. The insulin secretion curves of morbidly obese groups showed hyperinsulinemia before surgery. The peak of insulin secretion curve in IGT and DM group moved back to postprandial 120-minute before operation, and returned to 60-minute after operation, with basic normal rhythm of secretion curve. Preoperative HOMA-IR in all 3 morbidly obese groups was higher than that in control group (all P<0.05) and remarkably lower at postoperative 6-month compared to pre-operation(P<0.05). In 3 morbidly obese groups after operation, TG decreased, HDL-C increased, UA and TNF-α decreased significantly compared to before operation (all P<0.05). At postoperative 6-month, the HOMA-IR of DM group was positively correlated with BMI (r=0.236, P=0.004) and TNF-α (r=0.228, P=0.033), and was not correlated with HDL-C(P>0.05).

LSG can effectively ameliorate hyperinsulinemia and insulin secretion curve, and improve metabolic disorder and insulin resistance of different stage in obesity patients with glucose metabolic disorder. Insulin resistance is correlated with body weight and inflammatory factors.