Cardiac Microvascular Endothelial Enhancement of Cardiomyocyte Function Is Impaired by Inflammation and Restored by Empagliflozin

•

CMECs exert a direct positive effect on cardiomyocyte contraction and relaxation, which is mainly mediated by endothelial-derived NO.

•

Pro-inflammatory stimulation of CMECs by pre-incubation with TNF-α or interleukin-1β abrogates the positive regulatory function of these cells on cardiomyocyte contractile property.

•

Mechanistically, pro-inflammatory activation of CMECs leads to mitochondrial and cytoplasmic ROS accumulation that results in the scavenging of NO.

•

Empagliflozin directly restores the beneficial effect of CMECs on cardiomyocyte contraction and relaxation by reducing TNF-α-induced mitochondrial and cytoplasmic ROS accumulation, which leads to reinstatement of CMEC-derived NO delivery.

The positive findings of the EMPA-REG OUTCOME trial (Randomized, Placebo-Controlled Cardiovascular Outcome Trial of Empagliflozin) on heart failure (HF) outcome in patients with type 2 diabetes mellitus suggest a direct effect of empagliflozin on the heart. These patients frequently have HF with preserved ejection fraction (HFpEF), in which a metabolic risk-related pro-inflammatory state induces cardiac microvascular endothelial cell (CMEC) dysfunction with subsequent cardiomyocyte (CM) contractility impairment. This study showed that CMECs confer a direct positive effect on contraction and relaxation of CMs, an effect that requires nitric oxide, is diminished after CMEC stimulation with tumor necrosis factor-α, and is restored by empagliflozin. Our findings on the effect of empagliflozin on CMEC-mediated preservation of CM function suggests that empagliflozin can be used to treat the cardiac mechanical implications of microvascular dysfunction in HFpEF.