Abstract 13255: Cardiac and Generalized SGLT2 Deficiency Does Not Protect Against Development of Heart Failure With Reduced Ejection Fraction in Mice

Abstract

Sodium-glucose cotransporter 2 inhibitors (SGLT2i), originally designed for the treatment of diabetes, exert profound cardiovascular benefit and are now the standard-of-care in all forms of heart failure (HF). The mechanism of their benefit in HF is unknown. We hypothesized SGLT2i act via an on-target, extra-cardiac mechanism to promote ketosis and improve myocardial energetics. Generalized- (gKO) and cardiac-specific (csKO) SGLT2 knockout mice were generated by breeding SGLT2 floxed mice with EIIa or αMHC Cre recombinase lines, respectively. While csKO grew and developed normally, gKO mice were slightly smaller compared to WT littermates. There was no baseline cardiac phenotype in either group. The gKO mice exhibited profound glucosuria, decreased fasting serum glucose and augmented fasting ketosis compared to controls, and comparable in magnitude to the metabolic effects of 14 days of treatment with empagliflozin (Empa, 50mg/kg/day orally) in WT mice. Targeted metabolomic analysis of gKO and Empa-treated WT mice identified increased circulating and myocardial levels of the ketone body 3-hydroxybutyrate (1.9-2.3x, p<0.01), along with an increase in a subset of tricarboxylic acid cycle intermediates and C4-OH, a ketone oxidation by-product. Empa treatment in WT mice following trans-aortic constriction with apical myocardial infarction (TAC/MI) improved LV dysfunction and pathological remodeling at 6 weeks (left ventricular ejection fraction (EF) 36±6 vs 28±9, p<0.03; tibia length-normalized biventricular weight 9.6±0.4 vs 11.3±1.6, p<0.001). In contrast, csKO and gKO mice subjected to TAC/MI had no difference in EF, strain, ventricular hypertrophy or dilation compared to WT controls. In conclusion, generalized SGLT2 deficiency phenocopies the metabolic effects of SGLT2i treatment but neither gKO nor csKO afford cardiac protection in an established HF model. These results suggest an off-target mechanism for beneficial effects of SGLT2i in HF.