In the present study, we found that the number of small vessels and CD31-positively stained cells, an surface marker of endothelial cells, in LV myocardium were remarkably higher in DCM rats treated with ADMSCs or sildenafil than in those DCM animals without treatment, whereas it was significantly higher in the combined therapy group than in other groups. This evidence concerns the gene PECAM1 and familial dilated cardiomyopathy.