PECAM1 and myocardial infarction: The importance of using Sca-1+ stem/progenitors was elegantly demonstrated by Wang et al. (2006), where post-MI, mice transplanted with cardiac-derived Sca-1+/CD31- cells showed significant cardiac functional improvement compared to mice treated with cardiac-derived Sca-1-/CD31- cells, emphasising the importance of Sca-1+ cells for cardiac reparative therapies [15].