This review provides mechanistic insight in the pleiotropic effects of sodium-glucose transporter-2 (SGLT-2) inhibitors with particular interest to the pathophysiology of heart failure. The SGLT-2 inhibitor empagliflozin has recently demonstrated an unprecedented 38% reduction in cardiovascular mortality in patients with diabetes. Despite modest effects on long-term glycemic control, highly significant reductions in heart failure admissions and end-stage kidney disease were observed. SGLT-2 inhibitors are the latest approved class of glucose-lowering agents. By blocking sodium/glucose uptake in the proximal tubules of the nephron, they induce glycosuria. Treatment with SGLT-2 inhibitors in diabetes leads to a sustained ∼1% reduction in glycated hemoglobin levels, with favorable reductions in both arterial blood pressure (∼3-6 mmHg) and body weight (∼2-4 kg/m2). However, those effects fail to explain fully the dramatic reduction in cardiovascular mortality, heart failure readmissions, and end-stage kidney disease. The unique pharmacological profile of SGLT-2 inhibitors puts them at the crossroads of important hemodynamic, neurohumoral, metabolic, and vascular endothelial pathways influencing cardiac and renal disease. SGLT-2 inhibitors decrease proximal tubular sodium and chloride reabsorption, leading to a reset of the tubuloglomerular feedback. This induces plasma volume contraction without activation of the sympathetic nerve system, decreases harmful glomerular hyper-filtration leading to better long-term renal preservation, and improves diuretic and natriuretic responses to other diuretic agents. Moreover, SGLT-2 inhibitors might improve the efficiency of myocardial energetics by offering β-hydroxybutyrate as an attractive fuel for oxidation and increase hematocrit improving oxygen transport. Finally, decreased vascular stiffness and improved endothelial function are observed with the use of SGLT-2 inhibitors in diabetes. Those multiple nonglycemic effects reinforce SGLT-2 inhibitors as the preferred glucose-lowering drug to treat diabetic patients with heart failure. In the future, they might even be considered in heart failure or chronic kidney disease patients without diabetes.
Keywords: Diabetes mellitus; Energy metabolism; Glomerular filtration rate; Heart failure; Plasma volume; Sodium-glucose transporter 2.