Background: Bariatric surgery (BS) is able to positively influence fasting lipid profile in obese type 2 diabetic patients (T2DM), but no data is available on the impact of BS on postprandial lipid metabolism neither on its relation with incretin hormones. We evaluated the short-term (2 weeks) effects of BS on fasting and postprandial lipid metabolism in obese T2DM patients and the contribution of changes in active GLP-1.
Methods: We studied 25 obese T2DM patients (age = 46 ± 8 years, BMI = 44 ± 7 kg/m2), of which 15 underwent sleeve gastrectomy and 10 underwent gastric bypass. Lipid and incretin hormone concentrations were evaluated for 3 h after ingestion of a liquid meal before and 2 weeks after BS.
Results: After BS, there was a significant reduction in body weight (p < 0.001), fasting plasma glucose (p < 0.001), fasting plasma insulin (p < 0.05), HOMA-IR (p < 0.001), and fasting plasma lipids (p < 0.05). The meal response of plasma triglycerides, total cholesterol, and HDL cholesterol was significantly lower compared to pre-intervention (p < 0.05, p < 0.001). In particular, the incremental area under the curve (IAUC) of plasma triglycerides decreased by 60% (p < 0.005). The meal-stimulated response of active GLP-1 increased, reaching a statistical significance (p < 0.001).
Conclusions: BS leads to an early improvement of fasting and postprandial lipemia. The fall in fasting triglycerides is associated with an improvement of insulin resistance, while the reduction of postprandial lipemia is likely related to reduced intestinal lipid absorption consequent to bariatric surgery.