Changes in gastrointestinal motility and gut hormone secretion after Roux-en-Y gastric bypass and sleeve gastrectomy for individuals with severe obesity.

Background: Bariatric surgery is very effective in long-term weight management. The present study was undertaken to investigate the short-term effects of sleeve gastrectomy (SG) and of Roux-en-Y gastric bypass (RYGB) on (a) gastrointestinal (GI) motility, that is gastric emptying and oro-cecal transit time and (b) secretion of regulatory gut peptides and (c) their interrelationship.

Methods: Prospective single-centre study in which we assessed gastric emptying, oro-cecal transit time and gut peptide release in 28 severely obese individuals before and 2, respectively, 12 months after bariatric surgery (either SG or RYGB). Plasma PYY, GLP-1, ghrelin, insulin and glucose levels were measured fasting and after intake of a solid standard 459 kcal meal at each occasion. Gastric emptying was measured by 13 C octanoic acid breath testing, and oro-cecal transit time was measured by lactulose H₂ breath testing. Satiation was measured using VAS scores.

Results: After both RYGB and SG gastric emptying become significantly accelerated, and postprandial release of the distal gut peptides GLP-1 and PYY becomes significantly increased, pointing to ileal brake activation. Oro-cecal transit time becomes significantly accelerated after SG but not after RYGB. No significant correlations were observed between changes in distal gut peptide release, changes in GI motility and clinical parameters.

Conclusion: Both SG and RYGB resulted in significant weight loss and significantly affected GI motility and PYY and GLP-1 secretion. Subtle differences between both procedures were found in effect on oro-cecal transit time and patterns of peptide secretion.