Roux-en-Y Gastric Bypass is Associated With Increased Intestinal Glucose Uptake in Humans

In animal models, Roux-en-Y gastric bypass (RYGB) is associated with increased Roux limb intestinal glucose uptake that may contribute to early metabolic benefits, though prospective clinical studies are lacking.

The present study aimed to test the hypothesis that Roux limb glucose uptake would increase relative to baseline in a cohort of patients undergoing RYGB.

RYGB patients underwent preoperative baseline, and 3- and 6-month positron emission tomography/computed tomography postoperative imaging. Maximum and mean standardized uptake values (SUV) were measured from the following predefined regions of interest: cecum, hepatic flexure, splenic flexure, sigmoid colon, duodenal bulb, Roux limb, and common channel. SUV ratios were normalized to the spleen for assessment of longitudinal change.

Despite significant weight loss in all patients, no changes in Roux limb glucose uptake were observed relative to baseline; however, marked increases in glucose uptake were detected in the colon (cecum, hepatic flexure, and sigmoid colon) by 3 months that were maintained at 6 months (P < .05).

RYGB is associated with increased intestinal glucose uptake in humans, but this increase appears limited to the colon in the early postoperative period up to 6 months. While the marked increases in Roux limb glucose uptake may contribute to weight loss in rodent models, this mechanism does not appear to translate to human physiology. Unexpected increases in colonic glucose uptake warrant dedicated mechanistic studies to determine the clinical significance of these changes.