Improvements in glucose metabolism early after gastric bypass surgery are not explained by increases in total bile acids and fibroblast growth factor 19 concentrations

Abstract

Context: Bile acids and fibroblast growth factor 19 (FGF19) have been suggested as key mediators of the improvements in glucose metabolism after Roux-en-Y gastric bypass (RYGB). Objective: To describe fasting and postprandial state total bile acid (TBA)and FGF19 concentrations before and after RYGB and relate them to parameters of glucose metabolism, glucagon-like peptide-1, cholecystokinin, and cholesterol fractions. Design and Setting: A prospective descriptive study was performed at the Department of Endocrinology, Hvidovre Hospital, Hvidovre, Denmark. Patients: Thirteen type 2 diabetic (T2D) patients and 12 normal glucose tolerant (NGT) subjects participated in the study. Intervention: A 4-hour liquid meal test was performed before and 1 week, 3 months, and 1 year after RYGB. Main Outcome Measures: We measured fasting and postprandial TBA and FGF19 concentrations. Results: Fasting TBA concentrations decreased in NGT subjects (P < .001) and were unchanged in T2D patients 1 week after surgery, but then increased gradually in both groups with time from surgery (ANOVA Ptime < .001), resembling the changes seen with AUC TBA. One week after RYGB, glucose metabolism improved, low-density lipoprotein-cholesterol and high-density lipoprotein-cholesterol decreased, and cholecystokinin and glucagon-like peptide-1 secretion increased, whereas FFA concentrations were unchanged. Conclusion: TBA and FGF19 do not explain acute changes in glucose metabolism, cholesterol fractions, and gut hormone secretion after RYGB.