Empagliflozin Supplementation in Cardioplegic Solution Improves Donor Heart Preservation by Maintaining Mitochondrial...

Prolonged cold ischemia and subsequent reperfusion are major causes of primary graft dysfunction in heart transplantation. Empagliflozin, a sodium-glucose cotransporter 2 (SGLT2) inhibitor, has shown cardioprotective effects in ischemia-reperfusion injury, but its role in donor heart preservation and the underlying mechanisms remain unexplored.

We evaluated the effects of empagliflozin supplementation in University of Wisconsin (UW) preservation solution using both in vitro and in vivo models. HL-1 cardiomyocytes were subjected to cold hypoxia/reoxygenation injury to simulate donor preservation conditions. A murine heterotopic heart transplantation model with 24-hour cold storage was used to assess graft function, myocardial injury, fibrosis, and immune response. Mechanistic studies were conducted using AMPK and Drp1 inhibitors to investigate mitochondrial signaling pathways.

Empagliflozin (500 nM) significantly improved cardiomyocyte viability, reduced apoptosis, and preserved mitochondrial membrane potential under cold hypoxia/reoxygenation stress. In vivo, empagliflozin-supplemented UW solution improved early graft contractility, attenuated myocardial injury, reduced serum injury markers, and alleviated histological damage and immune cell infiltration. Long-term follow-up revealed mitigation of chronic rejection, with reduced fibrosis, vasculopathy, and immune activation. Mechanistically, empagliflozin activated AMPK, inhibited Drp1 phosphorylation at Ser616, promoted mitochondrial fusion (Mfn1, OPA1), and preserved mitochondrial morphology. These protective effects were abolished by AMPK inhibition and restored by Drp1 inhibition, confirming AMPK-Drp1 pathway involvement.

Empagliflozin enhances donor heart preservation by mitigating cold ischemia-reperfusion injury through modulation of the AMPK-Drp1 signaling axis. This study extends the pharmacological profile of empagliflozin from metabolic regulation to donor heart preservation, highlighting its translational potential in clinical transplantation.