Isolation of Alde-High and Alde-Low EPCs. (A) EPCs were separated on the basis of ALDH activity into Alde-High and Alde-Low cells. The dotted lines represent samples containing cells with Aldefluor reagent and its inhibitor, whereas the solid lines represent samples containing cells with Aldefluor reagent alone. (B) HUVECs, Alde-High EPCs, and Alde-Low EPCs were analyzed by FACS for the expressions of CD31, CD105, KDR, VE-cadherin, CD34, CD166, c-kit, CD45, and CD14.