Losartan Inhibits Vascular Calcification by Suppressing the BMP2 and Runx2 Expression in Rats In Vivo

The blockade of renin-angiotensin II system has been shown to reduce morbidity and mortality in hypertension, atherosclerosis, diabetes and chronic kidney disease. Since vascular calcification (VC) is commonly found in these diseases, the aim of this study was to examine whether or not losartan, a widely used angiotensin II receptor blockers, inhibits VC in rats in vivo. A rat model of VC was generated by treating rats with a combination of warfarin and vitamin K1. Two weeks after the treatments, the rats were treated with vehicle or without losartan (100 ng/kg/day) for 2 weeks. At the end of the experiments, aortic arteries were isolated for the examination of calcification morphology, mRNA and protein expression of BMP2 and Runx2, and osteoblast differentiation. Warfarin and vitamin K instigated vascular remodeling with calcified plaques in the aortic arteries in rats. Losartan significantly attenuated warfarin- and vitamin K-induced vascular injury and calcification. Consistently, losartan suppressed the levels of mRNA and protein expression of BMP2 and Runx2, two key factors for VC. Further, vascular calcified lesion areas expressed angiotensin II 1 receptor (AT1R). Finally, losartan treatment significantly inhibited apoptosis in vascular smooth muscle cell (VSMC) in rat arteries. We conclude that losartan suppresses VC by lowering the expression of AT1R, Runx2 and BMP2, and by inhibiting the apoptosis of VSMC in rat aortic arteries.