Gut hormone release after gastric bypass depends on the length of the biliopancreatic limb

Background/Objectives Changes in gut hormone secretion are important for the anti-diabetic effects of bariatric surgery. Roux-en-Y gastric bypass (RYGB) with extended biliopancreatic limb (BPL) length may improve the metabolic outcomes when compared to the classical procedure. The purpose of this study was to compare the gut hormone responses to a liquid mixed meal after RYGB with one of two different BPL lengths. Subjects/Methods Non-diabetic weight-stable individuals previously submitted to classical RYGB (n = 9; BPL length: 87.8 +/- 20.5 cm) or long BPL RYGB (n = 11; BPL length: 200 cm) underwent a liquid mixed-meal tolerance test (MMTT). Blood was sampled at baseline and 15, 30, 45, 60, 90 and 120 min later for measurement of plasma glucose, enteropancreatic hormones and total bile acids (TBA). Results Plasma glucose excursion curves were similar in the two groups. The long BPL RYGB group displayed significantly higher fasting and post-prandial GLP-1 (t = 0 min, p = 0.01 and t = 45 min, p < 0.05; tAUC: 11,205 +/- 3399 vs 7889 +/- 1686 pmol/L x min, p = 0.02) and neurotensin (t = 0 min, p = 0.02; t = 45 min, p < 0.05 and t = 60 min, p < 0.01; tAUC: 18,392 +/- 7066 vs 11,437 +/- 3658 pmol/L x min, p = 0.02) levels, while responses of GIP (t = 15 min, p < 0.01), insulin and Cpeptide (t = 30 min, p < 0.001) were lower as compared to classical RYGB. There were no differences in glucagon, PP, PYY and TBA between the groups. Conclusions RYGB with a longer BPL results in a distinctive post-prandial hormone profile with augmented GLP-1 and neurotensin responses that could be beneficial for the metabolic outcomes of the surgery.