Objective:To analysis the feature of vascular calcification in the radial arteries from 30 uremia patients,observe the effect of high calcium and high phosphate enviroment on rat vascular smooth muscle cells(VSMCs) in vitro. Methods:Radial arteries from uremia patients were examined for calcification by von Kossa and Alizarin red staining. Expression of smooth muscle cells marker α-SMA and bone matrix protein OP were detected by immunohistochemistry. Rat VSMCs were cultured in high calcium/high phosphate medium for 10 days to detect calcium deposition,furthermore, expression of α-SMA and OP was analyzed by Western blot. Results:Radial artery calcification mainly located in the medial layer,which occurred in 11 uremia patients. Immunohistochemistry staining revealed that in the mild/moderate calcified arteries group,expression of α-SMA was 71.11% ± 4.93% and in severe calcification group was 54.66% ± 5.15%,significantly lower than that of none calcification group(89.54% ± 2.92%,P < 0.01). Furthermore,the content of bone matrix protein OP was also upregulated in the uremia arteries,in mild/moderate calcification group was 22.19% ± 7.12% and in severe calcification group was 37.87% ± 6.17%(compared with none calcification group,6.85% ± 6.19%,P < 0.01). Calcium deposition was observed in VSMCs cultured with high calcium/high phosphate medium for 10 days,and production of OP was increased,expression of α-SMA was decreased. Conclusion:Calcificated vascular from uremia patients displayed decreased expression of α-SMA and upregulation of OP protein in the media layer,which was correlated with high calcium plus phosphate product,indicating that VSMCs showed the feature of osteoblast-like cells.