Background & aims: Bariatric surgery reduces weight and improves glucose metabolism in obese patients. We investigated the effects of bariatric surgery on hepatic insulin sensitivity.
Methods: Twenty-three morbidly obese (nine diabetic and fourteen non-diabetic) patients and ten healthy, lean control subjects were studied using positron emission tomography to assess hepatic glucose uptake in the fasting state and during euglycemic hyperinsulinemia. Magnetic resonance spectroscopy was performed to measure liver fat content and magnetic resonance imaging to obtain liver volume. Obese patients were studied before bariatric surgery (either sleeve gastrectomy or Roux-en-Y gastric bypass) and six months after surgery.
Results: Insulin-induced hepatic glucose uptake was increased by 33% in non-diabetic and by 36% in diabetic patients at follow-up compared with baseline, but not totally normalized. The liver fat content was reduced by 76%, liver volume by 26% and endogenous glucose production by 19% in non-diabetic patients. The respective changes in diabetic patients were 73%, 24%, and 25%. Postoperatively, liver fat content and endogenous glucose production were almost normalized to lean controls, but liver volume remained greater than in control subjects.
Conclusions: This study shows that bariatric surgery leads to a significant improvement in hepatic insulin sensitivity: insulin-stimulated hepatic glucose uptake was improved and endogenous glucose production reduced when measured, six-months, after surgery. These metabolic effects were accompanied by a marked reduction in hepatic volume and fat content. Overall, the gain in hepatic insulin sensitivity in diabetic patients was quite similar to non-diabetic patients for the same weight reduction.
Trial registration: ClinicalTrials.gov NCT00793143.
Keywords: (18)F-FDG; (18)F-fluorodeoxyglucose; BS; Bariatric surgery; Beta cell function; EGP; Endogenous glucose production; GLP-1; HGU; HbA(1c); Hepatic glucose uptake; IL-6; IL-8; Insulin clearance; LFC; Liver fat; MCP-1; MRI; MRS; OGTT; PET; RYGB; Roux-en-Y gastric bypass; SG; Sleeve gastrectomy; T2DM; VLCD; bariatric surgery; endogenous glucose production; glucagon-like peptide-1; glycosylated haemoglobin; hepatic glucose uptake; high-sensitivity C-reactive protein; hs-CRP; interleukin-6; interleukin-8; liver fat content; magnetic resonance imaging; magnetic resonance spectroscopy; monocyte chemotactic protein-1; oral glucose tolerance test; positron emission tomography; sleeve gastrectomy; type 2 diabetes; very-low-calorie diet.
Copyright © 2013. Published by Elsevier B.V.