323-OR: SGLT2 Inhibition Promotes Myocardial Ketone Utilization in the Normal and Failing Heart.

Recent clinical outcome studies demonstrate that SGLT2 inhibitors (i) significantly reduce major adverse cardiovascular events and heart failure in patients with and without type 2 diabetes; however, the mechanisms by which SGLT2i exert their cardiovascular benefits remain unclear. Here, we aimed to elucidate the acute effects of SGLT2i (dapagliflozin, dapa) on cardiac mitochondrial substrate oxidation. Using LC-MS/MS methodology combined with an infusion of [13C6]glucose and [13C4]βOHB, we assessed the ratio of cardiac mitochondrial pyruvate (VPDH) and βOHB (VβOHB) oxidation rates to rates of mitochondrial citrate synthase flux (VCS) in awake male Sprague Dawley (SD) rats. Metabolic studies were performed 4-6 h after oral dapa (1.5 mg/kg) or vehicle treatment in control rats and after induction of heart failure induced by permanent ligation of the left anterior descending coronary artery. Acute dapa treatment led to marked glycosuria with a 15% reduction in fasting plasma glucose concentrations and 50% increase in whole-body βOHB turnover and plasma βOHB concentrations (all P<0.05 vs. VEH). Dapa caused a 40-60% decrease in myocardial [14C]deoxyglucose uptake and pyruvate oxidation (VPDH/VCS) and a 60% increase in myocardial ketone oxidation (VβOHB/VCS) (all P<0.05 vs. VEH). Similar effects were observed in heart failure rats. Dapa treatment caused a 15% decrease in fasting plasma glucose concentrations, 50% increase in plasma βOHB levels and 60% increase in left ventricular VβOHB/VCS (all P<0.05 vs. VEH). Conclusion: Collectively, these studies demonstrate that dapa shifts both the normal and failing heart to increased mitochondrial ketone oxidation, which may be mediated by increased hepatic ketogenesis and βOHB availability. Disclosure: L. Goedeke: None. X. Zhang: None. R. J. Perry: None. G. Cline: None. L. H. Young: None. G. I. Shulman: Consultant; Self; 89bio, Inc., BridgeBio, Ionis Pharmaceuticals, Maze Therapeutics, Novo Nordisk, Other Relationship; Self; AstraZeneca, Esperion Therapeutics, Inc, Generian Pharmaceuticals, Inc., Gilead Sciences, Inc., iMetabolic Biopharma Corporation, Janssen Research & Development, LLC, Merck & Co., Inc., The Liver Company. J. Lee: None. Y. Ma: None. X. Hu: None. J. Zhang: n/a. J. Dong: None. K. D. Galsgaard: None. N. Guerrera: None. S. Haedersdal: None. Funding: National Institutes of Health (R01DK113984, R01DK045735, K99HL150234); AstraZeneca [ABSTRACT FROM AUTHOR]