Class effects of SGLT2 inhibitors in mouse cardiomyocytes and hearts: inhibition of Na(+)/H(+) exchanger, lowering of cytosolic Na(+) and vasodilation

AIMS/HYPOTHESIS: Sodium–glucose cotransporter 2 (SGLT2) inhibitors (SGLT2i) constitute a novel class of glucose-lowering (type 2) kidney-targeted agents. We recently reported that the SGLT2i empagliflozin (EMPA) reduced cardiac cytosolic Na(+) ([Na(+)](c)) and cytosolic Ca(2+) ([Ca(2+)](c)) concentrations through inhibition of Na(+)/H(+) exchanger (NHE). Here, we examine (1) whether the SGLT2i dapagliflozin (DAPA) and canagliflozin (CANA) also inhibit NHE and reduce [Na(+)](c); (2) a structural model for the interaction of SGLT2i to NHE; (3) to what extent SGLT2i affect the haemodynamic and metabolic performance of isolated hearts of healthy mice. METHODS: Cardiac NHE activity and [Na(+)](c) in mouse cardiomyocytes were measured in the presence of clinically relevant concentrations of EMPA (1 μmol/l), DAPA (1 μmol/l), CANA (3 μmol/l) or vehicle. NHE docking simulation studies were applied to explore potential binding sites for SGTL2i. Constant-flow Langendorff-perfused mouse hearts were subjected to SGLT2i for 30 min, and cardiovascular function, O(2) consumption and energetics (phosphocreatine (PCr)/ATP) were determined. RESULTS: EMPA, DAPA and CANA inhibited NHE activity (measured through low pH recovery after NH(4) (+) pulse: EMPA 6.69 ± 0.09, DAPA 6.77 ± 0.12 and CANA 6.80 ± 0.18 vs vehicle 7.09 ± 0.09; p < 0.001 for all three comparisons) and reduced [Na(+)](c) (in mmol/l: EMPA 10.0 ± 0.5, DAPA 10.7 ± 0.7 and CANA 11.0 ± 0.9 vs vehicle 12.7 ± 0.7; p < 0.001). Docking studies provided high binding affinity of all three SGLT2i with the extracellular Na(+)-binding site of NHE. EMPA and CANA, but not DAPA, induced coronary vasodilation of the intact heart. PCr/ATP remained unaffected. CONCLUSIONS/INTERPRETATION: EMPA, DAPA and CANA directly inhibit cardiac NHE flux and reduce [Na(+)](c), possibly by binding with the Na(+)-binding site of NHE-1. Furthermore, EMPA and CANA affect the healthy heart by inducing vasodilation. The [Na(+)](c)-lowering class effect of SGLT2i is a potential approach to combat elevated [Na(+)](c) that is known to occur in heart failure and diabetes. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1007/s00125-017-4509-7) contains peer-reviewed but unedited supplementary material, which is available to authorised users.