254-LB: In Vivo Mapping of Postprandial Hepatic Glucose Metabolism Using Stable Isotope-Assisted Metabolic Imaging in Roux-en-Y Gastric Bypass Adults and Nonoperated Controls

Abstract

We aimed to assess the impact of Roux-en-Y gastric bypass (RYGB) on hepatic glucose (glc) kinetics using stable isotope-assisted magnetic resonance spectroscopy (MRS). Ten post-RYGB adults (2M, age=39.2±3.1 y, BMI=28±1 kg/m2; mean±SE) and ten non-operated adults (HC; 5M, age=36.4±3.2 y, BMI=26±1 kg/m2) underwent metabolic imaging in a 7T (Terra, Siemens) scanner with a triple-tuned surface coil over the liver. Scanning was performed before (T0) and up to 150 min (T150) after oral intake of 60g of deuterated [6,6′-2H2]-Glc using interleaved sequences of 2H2-MRS imaging (hepatic 2H2-glc signal) and 13C-MRS (glycogen). Blood samples were collected for profiling of plasma glc, glc enrichment, insulin and glucagon. General Additive Mixed Models were used for comparative analyses. We observed distinct postprandial profiles of hepatic glc signal (Fig 1). RYGB subjects showed earlier and higher glc peaks, which were mirrored by hepatic glc signal in both groups. Insulin peak levels were higher and glc nadir lower in RYGB. Postprandial endogenous glc was higher in RYGB, which was paralleled by a fall in hepatic glc. In HC, hepatic glc remained elevated until the end of the experiment. Non-invasive stable isotope-assisted MRS imaging has the potential to unravel changes in postprandial hepatic metabolism induced by RYGB and other treatments. Disclosure N. F. Lange: None. S. Poli: None. D. Herzig: None. M. Schiavon: None. C. Dalla man: Research Support; Sanofi-Aventis Deutschland GmbH, Becton, Dickinson and Company. R. Kreis: None. L. Bally: Research Support; Dexcom, Inc., Ypsomed AG. Funding Swiss National Science Foundation (PCEGP3_186978)