An Inhibitor of Activated Blood Coagulation Factor X Shows Anti-Endothelial Senescence and Anti-Atherosclerotic Effects

Abstract

Background: Coagulant factor Xa inhibitors (XaIs) are prescribed for patients with atrial fibrillation for years. Methods: Human umbilical venous endothelial cells (HUVECs) were cultured with or without (w/wo) a XaI (rivaroxaban) under high glucose (HG: 22 mM). Endothelial senescence was investigated by assessing senescence-associated-β-galactosidase (SA-β-gal), p53, and telomere length. Endothelial function and atherosclerosis were examined by nitric oxide-related-products (NOx: NO₂^– and NO₃^–), O₂^–, endothelial NO synthase (eNOS), NADPH oxidase (p22^phox), and ICAM1. PAR1 (protease-activated receptor 1) and PAR2, which were reported to regulate eNOS phosphorylation, were inhibited by small interfering RNAs (siRNAs). Thirty-two male dyslipidemic type 2 diabetic rats (ZFDM LepR^fa/fa) were fed a high-cholesterol diet w/wo XaI (50 µg/day/kg) for 1–4 weeks. Results: SA-β-gal, p53, p21, and p16^INK4a were increased by HG and restored by XaI (50 nM) in HUVECs. XaI restored telomerase activity and preserved telomere length. XaI suppressed O₂^–, p22^phox, and ICAM1 and restored NOx and eNOS. XaI decreased PAR1 following elevation by HG, which was confirmed by PAR1 siRNA and PAR2 siRNA. In in vivo experiments, plasma glucose, total cholesterol, and triglycerides were increased for 4 weeks but were not changed by XaI. XaI decreased SA-β-gal and telomerase and preserved telomere length in the aortic endothelium. XaI activated eNOS, inhibited p22^phox, increased plasma NOx, and decreased O₂^–. Conclusion: Rivaroxaban prevents replicative senescence in HUVECs and aortic endothelial cells in dyslipidemic diabetic mice. It restores endothelial function and prevents the progression of atherosclerosis.