Empagliflozin prevents TNF-α induced endothelial dysfunction under flow -the potential involvement of calcium and sodium-hydrogen exchanger

Background

Empagliflozin (EMPA) attenuates inflammation-induced ROS generation in static endothelial cells through inhibition of sodium hydrogen exchanger 1 (NHE1) and modulation of ion homeostasis. We hypothesize that EMPA will alleviate TNF-α stimulated endothelial dysfunction under flow conditions, and that this might be mediated by NHE1 and intracellular Ca²⁺.

Methods

Human coronary artery endothelial cells were pre-treated with EMPA or vehicle before starting flow with or without TNF-α. Intracellular Ca²⁺ was recorded for 5 min at the start of flow. ROS generation and NO bioavailability, Piezo-1, cytokines, adhesion molecules, VE-cadherin and eNOS were detected after 6 h. BAPTA-AM was applied to chelate intracellular Ca²⁺ and NHE1 was knocked down with specific siRNA.

Results

Under flow conditions, EMPA inhibited ROS production and [Ca²⁺] increase in cells exposed to TNF-α (P < 0.05). BAPTA-AM and NHE1 knockdown both reduced ROS generation (P < 0.05), and genetical inhibition of NHE1 led to reduction of intracellular [Ca²⁺] in HCAECs receiving TNF-α (P < 0.05). Yet, EMPA showed no effect on the increased cytokine production, adhesion molecule expression and phosphorylation of eNOS in endothelial cells exposed to TNF-α.

Conclusion

EMPA mitigates increased ROS production and impaired NO bioavailability in TNF-α stimulated cells under flow. The anti-oxidative effect of EMPA is mediated by the decreased intracellular [Ca²⁺] following NHE1 inhibition.