Background: Recent investigations have linked elevated gastrin levels to the improvement of type 2 diabetes mellitus (T2DM). Roux-en-Y gastric bypass (RYGB) and sleeve gastrectomy (SG) are effective treatments for T2DM, but it is not known if this is related to postoperative alterations of gastrin secretion.
Methods: Twenty women previously operated with RYGB or SG and 13 female controls were enrolled and evaluated for body mass index, lipids, C-peptide, HbA1c, and anti-H. pylori IgG. Glucose, gastrin, insulin, and glucagon-like peptide 1 (GLP-1) concentrations were measured before and 30, 60, 90, and 120 min after ingestion of a protein-rich mixed meal.
Results: Six participants primarily selected were excluded due to usage of proton pump inhibitors, positive H.pylori IgG, or history of T2DM, yielding the following groups: RYGB (n = 9), SG (n = 8), and controls (n = 10). There were no differences in age, body mass index, HbA1c, or C-peptide levels between groups. RYGB had significantly lower area under the curve (AUC) for glucose during the test compared to controls (p = 0.013). RYGB showed lower serum gastrin levels compared to SG and controls (p < 0.05 for all). There was a non-significant increased gastrin release in SG compared to controls (p = 0.091). For SG and controls, there was a negative correlation between glucose and gastrin response (p = 0.0043).
Conclusion: Gastrin secretion is diminished after RYGB. Hypergastrinemia was not present after SG, but a tendency of enhanced gastrin secretion was observed. These findings require further investigation in prospective studies.
Keywords: Gastrin; Glucagon-like peptide 1; Glycemic control; Glycosylated hemoglobin; Insulin; Mixed meal tolerance test; Roux-en-Y gastric bypass; Sleeve gastrectomy.