Empagliflozin decreases myocardial cytoplasmic Na+ through inhibition of the cardiac Na+/H+ exchanger in rats and rabbits

Antonius Baartscheer, Cees A. Schumacher, Rob C.I. Wüst, Jan W.T. Fiolet, Ger J.M. Stienen, Ruben Coronel, Coert J. Zuurbier*

*Corresponding author for this work

Research output: Contribution to JournalArticleAcademicpeer-review

Abstract

Aims/hypothesis: Empagliflozin (EMPA), an inhibitor of the renal sodium–glucose cotransporter (SGLT) 2, reduces the risk of cardiovascular death in patients with type 2 diabetes. The underlying mechanism of this effect is unknown. Elevated cardiac cytoplasmic Na+ ([Na+]c) and Ca2+ ([Ca2+]c) concentrations and decreased mitochondrial Ca2+ concentration ([Ca2+]m) are drivers of heart failure and cardiac death. We therefore hypothesised that EMPA would directly modify [Na+]c, [Ca2+]c and [Ca2+]m in cardiomyocytes. Methods: [Na+]c, [Ca2+]c, [Ca 2+]m and Na+/H+ exchanger (NHE) activity were measured fluorometrically in isolated ventricular myocytes from rabbits and rats. Results: An increase in extracellular glucose, from 5.5 mmol/l to 11 mmol/l, resulted in increased [Na+]c and [Ca2+]c levels. EMPA treatment directly inhibited NHE flux, caused a reduction in [Na+]c and [Ca2+]c and increased [Ca2+]m. After pretreatment with the NHE inhibitor, Cariporide, these effects of EMPA were strongly reduced. EMPA also affected [Na+]c and NHE flux in the absence of extracellular glucose. Conclusions/interpretation: The glucose lowering kidney-targeted agent, EMPA, demonstrates direct cardiac effects by lowering myocardial [Na+]c and [Ca2+]c and enhancing [Ca2+]m, through impairment of myocardial NHE flux, independent of SGLT2 activity.

Original languageEnglish
Pages (from-to)568-573
Number of pages6
JournalDiabetologia
Volume60
Issue number3
DOIs
Publication statusPublished - 1 Mar 2017

Keywords

  • Calcium
  • Cardiac death
  • Diabetes
  • Glucose
  • Heart failure
  • Sodium

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