PECAM1 and myocardial infarction: As neovascularization/angiogenesis are essential for cardiac repair post MI 27, we performed evaluation of vessel density in the border zone of the infarct by CD31 staining, and found that CD31 positive vessels were significantly decreased in db/db EPC-EV treated mice compared with db/+ EPC-EV treated mice (Figure 2I-J).