CXCL12 and atherosclerosis: Given the relevance of CXCL12 in the recruitment of progenitor cells, vascular repair and postinjury remodeling as well as primary and secondary atherosclerosis [8], we investigated the pattern of CXCL12 expression and release by EPCs and SMCs not only in monoculture but also following co-cultivation allowing EPC–SMC interaction.