Acute Changes in Non-esterified Fatty Acids in Patients with Type 2 Diabetes Receiving Bariatric Surgery

Background: The purpose of this study was to compare acute changes of non-esterified fatty acids (NEFA) in relation to beta cell function (BCF) and insulin resistance in obese patients with type 2 diabetes (T2D) who underwent laparoscopic gastric bypass (GBP), laparoscopic sleeve gastrectomy (SG) or very low calorie diet (VLCD). Methods: In a non-randomised study, fasting plasma samples were collected from 38 obese patients with T2D, matched for age, body mass index (BMI) and glycaemic control, who underwent GBP (11) or SG (14) or VLCD (13). Samples were collected the day before and 3 days after the intervention, during a 75-g oral glucose tolerance test. Glucose, insulin, c-peptide, glucagon like peptide-1 (GLP-1) and gastric inhibitory polypeptide (GIP) were measured, and individual NEFAs were measured using a triple-quadrupole liquid chromatography-mass spectrometry (LC-MS/MS). BCF by mathematical modelling and insulin resistance were estimated. Results: Palmitic acid significantly decreased after each intervention. Monounsaturated/polyunsaturated ratio (MUFA/PUFA) and unsaturated/saturated fat ratios increased after each intervention. BCF was improved only after VLCD. Linoleic acid was positively correlated with total insulin secretion (p = 0.03). Glucose sensitivity correlated with palmitic acid (p = 0.01), unsaturated/saturated ratio (p = 0.0008) and MUFA/PUFA (p = 0.009). HOMA-IR correlated with stearic acid (p = 0.03), unsaturated/saturated ratio (p = 0.005) and MUFA/PUFA (p = 0.009). GIP AUC0-120 correlated with stearic acid (p = 0.04), but not GLP-1. Conclusions: GBP, SG and VLCD have similar acute effects on decreasing palmitic acid. Several NEFAs correlated with BCF parameters and HOMA-IR.