GLP-1 Response to a Mixed Meal: What Happens 10 Years after Roux-en-Y Gastric Bypass (RYGB)?

Background Oral meal consumption increases glucagon-like peptide 1 (GLP-1) release which maintains euglycemia by increasing insulin secretion. This effect is exaggerated during short-term follow-up of Roux-en-y gastric bypass (RYGB). We examined the durability of this effect in patient with type 2 diabetes (T2DM) >10 years after RYGB. Methods GLP-1 response to a mixed meal in the 10-year post-RYGB group ( n = 5) was compared to lean ( n = 9), obese ( n = 6), and type 2 diabetic ( n = 10) controls using a cross-sectional study design. Analysis of variance (ANOVA) was used to evaluate GLP-1 response to mixed meal consumption from 0 to 300 min, 0–20 min, 20–60 min, and 60–300 min, respectively. Weight, insulin resistance, and T2DM were also assessed. Results GLP-1 response 0–300 min in the 10-year post-RYGB showed a statistically significant overall difference ( p = 0.01) compared to controls. Furthermore, GLP-1 response 0–20 min in the 10-year post-RYGB group showed a very rapid statistically significant rise ( p = 0.035) to a peak of 40 pM. GLP-1 response between 20 and 60 min showed a rapid statistically significant ( p = 0.041) decline in GLP-1 response from ~40 pM to 10 pM. GLP-1 response in the 10-year post-RYGB group from 60 to 300 min showed no statistically significant difference from controls. BMI, HOMA, and fasting serum glucose before and >10 years after RYGB changed from 59.9 → 40.4, 8.7 → 0.88, and 155.2 → 87.6 mg/dl, respectively, and were statistically significant ( p