PET-CT reveals increased intestinal glucose uptake after gastric surgery.

Background: Mechanisms of metabolic improvement after bariatric surgery remain incompletely understood. Intestinal glucose uptake is increased after gastric bypass in rodents, potentially contributing to reduced blood glucose and type 2 diabetes remission.

Objective: We assessed whether intestinal glucose uptake is increased in humans after gastric surgery.

Setting: University Hospital, United States.

Methods: In a retrospective, case-control cohort study, positron emission tomography-computerized tomography scans performed for clinical indications were analyzed to quantify intestinal glucose uptake in patients with or without history of gastric surgery. We identified 19 cases, defined as patients over age 18 with prior gastric surgery (Roux-en-Y gastric bypass [n = 10], sleeve gastrectomy [n = 1], or Billroth I [n = 2] or II gastrectomy [n = 6]), and 43 controls without gastric surgery, matched for age, sex, and indication for positron emission tomography-computerized tomography. Individuals with gastrointestinal malignancy or metformin treatment were excluded. Images were obtained 60 minutes after F-fluorodeoxyglucose injection (4.2 MBq/kg), and corrected by attenuation; noncontrast low-dose computerized tomography was obtained in parallel. Fused and nonfused images were analyzed; standardized uptake values were calculated for each region by volumes of interest at the region of highest activity.

Results: Both standardized uptake values maximum and mean were significantly increased by 41% to 98% in jejunum, ascending, and transverse colon in patients with prior gastric surgery (P < .05 versus controls).

Conclusion: Intestinal glucose uptake is increased in patients with prior gastric surgery. Prospective studies are important to dissect the contributions of weight loss, dietary factors, and systemic metabolism, and to determine the relationship with increased insulin-independent glucose uptake and reductions in glycemia.