Aims Sodium–glucose co‐transporter 2 (SGLT2) inhibition reduces heart failure hospitalizations in patients with diabetes, irrespective of glycaemic control. We examined the effect of SGLT2 inhibition with empagliflozin (EMPA) on cardiac function in non‐diabetic rats with left ventricular (LV) dysfunction after myocardial infarction (MI). Methods and results Non‐diabetic male Sprague–Dawley rats underwent permanent coronary artery ligation to induce MI, or sham surgery. Rats received chow containing EMPA that resulted in an average daily intake of 30 mg/kg/day or control chow, starting before surgery (EMPA‐early) or 2 weeks after surgery (EMPA‐late). Cardiac function was assessed using echocardiography and histological and molecular markers of cardiac remodelling and metabolism were assessed in the left ventricle. Renal function was assessed in metabolic cages. EMPA increased urine production by two‐fold without affecting creatinine clearance and serum electrolytes. EMPA did not influence MI size, but LV ejection fraction (LVEF) was significantly higher in the EMPA‐early and EMPA‐late treated MI groups compared to the MI group treated with vehicle (LVEF 54%, 52% and 43%, respectively, all P < 0.05). EMPA also attenuated cardiomyocyte hypertrophy, diminished interstitial fibrosis and reduced myocardial oxidative stress. EMPA treatment reduced mitochondrial DNA damage and stimulated mitochondrial biogenesis, which was associated with the normalization of myocardial uptake and oxidation of glucose and fatty acids. EMPA increased circulating ketone levels as well as myocardial expression of the ketone body transporter and two critical ketogenic enzymes, indicating that myocardial utilization of ketone bodies was increased. Together these metabolic changes were associated with an increase in cardiac ATP production. Conclusion Empagliflozin favourably affects cardiac function and remodelling in non‐diabetic rats with LV dysfunction after MI, associated with substantial improvements in cardiac metabolism and cardiac ATP production. Importantly, it did so without renal adverse effects. Our data suggest that EMPA might be of benefit in heart failure patients without diabetes.

Background: Accumulating evidence suggests that the failing heart reprograms fuel metabolism toward increased utilization of ketone bodies and that increasing cardiac ketone delivery ameliorates cardiac dysfunction. As an initial step toward development of ketone therapies, we investigated the effect of chronic oral ketone ester (KE) supplementation as a prevention or treatment strategy in rodent heart failure models. Methods: Two independent rodent heart failure models were used for the studies: transverse aortic constriction/myocardial infarction (MI) in mice and post-MI remodeling in rats. Seventy-five mice underwent a prevention treatment strategy with a KE comprised of hexanoyl-hexyl-3-hydroxybutyrate KE (KE-1) diet, and 77 rats were treated in either a prevention or treatment regimen using a commercially available β-hydroxybutyrate-(R)-1,3-butanediol monoester (DeltaG; KE-2) diet. Results: The KE-1 diet in mice elevated β-hydroxybutyrate levels during nocturnal feeding, whereas the KE-2 diet in rats induced ketonemia throughout a 24-hour period. The KE-1 diet preventive strategy attenuated development of left ventricular dysfunction and remodeling post-transverse aortic constriction/MI (left ventricular ejection fraction±SD, 36±8 in vehicle versus 45±11 in KE-1; P =0.016). The KE-2 diet therapeutic approach also attenuated left ventricular dysfunction and remodeling post-MI (left ventricular ejection fraction, 41±11 in MI-vehicle versus 61±7 in MI-KE-2; P <0.001). In addition, ventricular weight, cardiomyocyte cross-sectional area, and the expression of ANP (atrial natriuretic peptide) were significantly attenuated in the KE-2–treated MI group. However, treatment with KE-2 did not influence cardiac fibrosis post-MI. The myocardial expression of the ketone transporter and 2 ketolytic enzymes was significantly increased in rats fed KE-2 diet along with normalization of myocardial ATP levels to sham values. Conclusions: Chronic oral supplementation with KE was effective in both prevention and treatment of heart failure in 2 preclinical animal models. In addition, our results indicate that treatment with KE reprogrammed the expression of genes involved in ketone body utilization and normalized myocardial ATP production following MI, consistent with provision of an auxiliary fuel. These findings provide rationale for the assessment of KEs as a treatment for patients with heart failure.

Saucedo-Orozco H, et al. J Lipid Atheroscler. 2022 Jan;11(1):1-19. https://doi.org/10.12997/jla.2022.11.1.1

The mechanism of action of empagliflozin in heart failure with reduced ejection fraction (HFrEF) was deciphered using deep learning in silico analyses together with in vivo validation. The most robust mechanism of action involved the sodium-hydrogen exchanger (NHE)-1 co-transporter with 94.7% accuracy, which was similar for diabetics and nondiabetics. Notably, direct NHE1 blockade by empagliflozin ameliorated cardiomyocyte cell death by restoring expression of X-linked inhibitor of apoptosis (XIAP) and baculoviral IAP repeat-containing protein 5 (BIRC5). These results were independent of diabetes mellitus comorbidity, suggesting that empagliflozin may emerge as a new treatment in HFrEF.