Upregulation of Intestinal Glucose Transporters after Roux-en-Y Gastric Bypass to Prevent Carbohydrate Malabsorption

ObjectiveTo determine the effect of Roux-en-Y gastric bypass (RYGB) on the expression of intestinal sweet taste receptors (STRs), glucose transporters (GTs), glucose absorption, and glycemia. MethodsIntestinal biopsies were collected for mRNA expression of STR (T1R2) and GTs (SGLT-1 and GLUT2) from 11 non-diabetic RYGB, 13 non-diabetic obese, and 11 healthy subjects, at baseline and following a 30 min small intestinal (SI) glucose infusion (30 g/150 ml water with 3 g 3-O-methyl-d-glucopyranose (3-OMG)). Blood glucose, plasma 3-OMG, and insulin were measured for 270 min. ResultsIn RYGB patients, expression of both GTs was approximate to 2-fold higher at baseline and after glucose infusion than those of morbidly obese or healthy subjects (P<0.001). STR expressions were comparable amongst the groups. Peak plasma 3-OMG in both RYGB (r=0.69, P=0.01) and obese (r=0.72, P=0.005) correlated with baseline expression of SGLT-1, as was the case with peak blood glucose in RYGB subjects (r=0.69, P=0.02). ConclusionsThe upregulated intestinal GTs in RYGB patients are associated with increased glucose absorption when glucose is delivered at a physiological rate, suggesting a molecular adaptation to prevent carbohydrate malabsorption from rapid intestinal transit after RYGB.