Taurine prevents β-glycerophosphate-induced calcification in cultured rat vascular smooth muscle cells

Vascular calcification is an ectopic calcification that commonly occurs in atherosclerosis. Because taurine was previously shown to protect against cardiovascular diseases, the effect of taurine on vascular calcification was evaluated in calcified vascular smooth muscle cells (VSMCs) of rat in vitro in the present study. Osteoblastic differentiation, calcification, and proliferation in VSMCs were detected in the presence and absence of taurine. Alkaline phosphatase (ALP), cellular calcium content, and Ca-45 accumulation were measured as the indicators of osteoblastic differentiation and calcification. Incubation of VSMCs with beta-glycerophosphate for 10 days induced an osteoblast-like morphological change. The activity of ALP was enhanced. Calcium content and Ca-45 uptake were increased in these cells. Calcification of these VSMCs was demonstrated with beta-glycerophosphate treatment. In association with these alterations, cell proliferation, detected by cell counting, [H-3]thymidine ([H-3]TdR), and [H-3]leucine ([H-3]Leu) incorporation, was also increased in these calcified VSMCs. Taurine at 20 mmol/l decreased calcium content, Ca-45(2+) uptake, and ALP activity both after early and late treatment, in which a reduction of the cell count, [H-3']TdR, and [H-3]Leu incorporation of calcified VSMCs was also noted. Compared with the calcified group, morphological changes in the VSMCs of the early-treated group were deferred. These results demonstrated that calcification of VSMCs could be alleviated by taurine. Taurine treatment appeared to be more beneficial when the treatment was started earlier.