Abstract
Background
Empagliflozin, an inhibitor of the sodium glucose co-transporter 2 (SGLT2), developed as an anti-diabetic agent exerts additional beneficial effects on heart failure outcomes in patients with type 2 diabetes mellitus at high cardiovascular risk. However, the effect of empagliflozin on vascular cell function and vascular remodeling processes remain largely elusive.
Methods/Results
Immunocytochemistry and immunoblotting revealed SGLT2 to be expressed in human diabetic and non-diabetic smooth muscle (SMC) and endothelial cells (EC) as well as in murine femoral arteries. In vitro, empagliflozin significantly reduced serum-induced proliferation and migration of human diabetic and non-diabetic SMCs in a dose-dependent manner without any toxic or apoptotic effects. In contrast, empagliflozin significantly increased the cell count and migrational capacity of human diabetic ECs, but not of human non-diabetic ECs. In vivo, therapeutic application of empagliflozin (225 mg/kg medicated diet) resulted in a significantly reduced number of Ki-67+ proliferating neointimal cells in response to femoral artery wire-injury in C57BL/6J mice. Empagliflozin furthermore prevented subsequent neointima formation (luminal stenosis 91.2% vs. 80.6% at 21 days; P<0.05). Comparable effects of empagliflozin were observed in a streptozocin-induced diabetic model of apolipoprotein E−/− mice. Conclusive to the in vitro-results, re-endothelialization was not significantly affected in C57BL/6 mice (non-reendothelialized distance 2.57 mm vs. 2.3 mm; P=0.07), but even significantly improved in diabetic mice after treatment with empagliflozin (3.1 mm vs. 2.58 mm; P<0.001) assessed by Evan's Blue staining 3 days after electric denudation of the murine carotid artery.
Microarray analysis of human SMCs identified the vasoactive peptide apelin to be decisively regulated in response to empagliflozin treatment. Further pathway analysis exhibited apelin to prevent SMC proliferation by de-phosphorylation of Akt and to augment EC proliferation by phosphorylation of p38 MAPK.
Conclusion
These data document the functional impact of empagliflozin on vascular SMCs and ECs for the first time. Empagliflozin significantly reduces serum-induced proliferation and migration of SMCs in vitro and prevented neointima formation in vivo, while augmenting EC proliferation in vitro and re-endothelialization in vivo after vascular injury. Thus, empagliflozin holds promise to exert favorable effects on vascular healing, and to prevent neointima formation following vascular injury in diabetic and non-diabetic patients.
Funding Acknowledgement
Type of funding source: Public Institution(s). Main funding source(s): Hannover Medical School, Martin-Luther-University Halle-Wittenberg
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