Empagliflozin reduces arrhythmogenic effects in rat neonatal and human iPSC-derived cardiomyocytes and improves cytosolic calcium handling at least partially independent of NHE1

Abstract

The antidiabetic agent class of sodium-glucose cotransporter 2 (SGLT2) inhibitors confer unprecedented cardiovascular benefits beyond glycemic control, including reducing the risk of fatal ventricular arrhythmias. However, the impact of SGLT2 inhibitors on the electrophysiological properties of cardiomyocytes exposed to stimuli other than hyperglycemia remains elusive. This investigation tested the hypothesis that the SGLT2 inhibitor empagliflozin (EMPA) affects cardiomyocyte electrical activity under hypoxic conditions. Rat neonatal and human induced pluripotent stem cell (iPSC)-derived cardiomyocytes incubated or not with the hypoxia-mimetic agent CoCl2 were treated with EMPA (1 μM) or vehicle for 24 h. Action potential records obtained using intracellular microelectrodes demonstrated that EMPA reduced the action potential duration at 30%, 50%, and 90% repolarization and arrhythmogenic events in rat and human cardiomyocytes under normoxia and hypoxia. Analysis of Ca2+ transients using Fura-2-AM and contractility kinetics showed that EMPA increased Ca2+ transient amplitude and decreased the half-time to recover Ca2+ transients and relaxation time in rat neonatal cardiomyocytes. We also observed that the combination of EMPA with the Na+/H+ exchanger isoform 1 (NHE1) inhibitor cariporide (10 µM) exerted a more pronounced effect on Ca2+ transients and contractility than either EMPA or cariporide alone. Besides, EMPA, but not cariporide, increased phospholamban phosphorylation at serine 16. Collectively, our data reveal that EMPA reduces arrhythmogenic events, decreases the action potential duration in rat neonatal and human cardiomyocytes under normoxic or hypoxic conditions, and improves cytosolic calcium handling at least partially independent of NHE1. Moreover, we provided further evidence that SGLT2 inhibitor-mediated cardioprotection may be partly attributed to its cardiomyocyte electrophysiological effects.

Impact of Impaired Kidney Function on Arrhythmia-Promoting Cardiac Ion Channel Regulation

“…SGLT2i treatment increased the expression of connexin 43, which was accompanied by a significant shortening of the QT interval, highlighting SGLT2i as a treatment option for malignant re-entry arrhythmias in CKD [ 7 , 106 ]. These findings are in line with data from Dos Santos et al, who demonstrated APD duration normalization by SGLT2i after hypoxia-induced APD prolongation in iPSC [ 107 ]. Increased late sodium current (I Na ) is a well-known mechanism of prolonged APD, with an increased risk of EADs [ 108 ] leading to ventricular arrhythmia.…”

Empagliflozin rescues pro-arrhythmic and Ca2+ homeostatic effects of transverse aortic constriction in intact murine hearts

“…We then demonstrated positive actions on indicators of cardiac hypertrophy and systolic function within the same hearts. This complemented previous findings in rats with mineralocorticoid-induced hypertension 21 , as well as recent suggestions from cardiomyocyte-level findings implicating electrophysiological effects in SGLT2i cardioprotective actions 22 . Finally we demonstrated actions on hypertrophic and contractile changes and on action potential waveform, intracellular Ca 2+ homeostasis and ventricular arrhythmogenicity.…”

“…Together these findings in the murine TAC experimental platform thus complement experimental studies in diabetic rats, high-fat-diet db/db mice and myocardial ischemic models. They further extend those earlier cellular level studies using the TAC experimental platform in isolated and or iPSC-derived ventricular cardiomyocytes bearing on APD 7 , 8 and I NaL 8 , 20 , 22 , and alterations in Ca 2+ homeostasis 8 , 11 , 12 reflecting CaMK-II mediated 11 , 13 actions on Ca 2+ signaling proteins including ryanodine receptor type II (RyR2) and phospholamban (PLN) 8 , 11 , 12 , 14 , 15 . Such cellular parameters translate to the level of intact hearts, in the form of the empagliflozin-induced rescues of compromised systolic function, ventricular hypertrophy, electrophysiological and intracellular Ca 2+ homeostatic changes, and arrhythmogenicity.…”

“…We here complement previous cellular-level studies reporting effects of the selective SGLT2i empagliflozin following TAC-induced HF and hypoxic stress on isolated cardiomyocytes, proceeding to study its effects on intact hearts . The previous reports had demonstrated SGLT2i actions on an altered pro-arrhythmic I NaL 20 , 22 , Ca 2+ homeostasis and CaMKII activity 13 , 22 in isolated and/or iPSC-derived ventricular cardiomyocytes. We now explore corresponding anatomical and systolic changes, related alterations in electrophysiological action potential properties, Ca 2+ homeostasis and CaMKII phosphorylation, and the consequent arrhythmic tendency at the level of intact TAC-HF hearts for the first time.…”

Evaluation of the effect of empagliflozin on prevention of atrial fibrillation after coronary artery bypass grafting: A double-blind, randomized, placebo-controlled trial

“…In this respect, SGLT2 inhibitors are now widely used in treating heart failure with or without DM2. Preclinical and retrospective human studies have recently suggested that SGLT2 inhibitors have an antiarrhythmic effect on atrial brillation and ventricular arrhythmias(Gao, Xue, et al, 2022).Silva dos Santos et al demonstrated that empagli ozin reduced arrhythmogenic events via enhancing [Ca 2+ ] transient recovery and improving relaxation kinetics in rat and human cardiomyocytes under hypoxia(Silva et al, 2023). In an animal study, the antiarrhythmic effects of empagli ozin were investigated in a model of global ischemia-reperfusion in rabbits.…”