hearts. Immunohistochemical analysis further confirmed that the Notch3 expression was localized to the wall of larger arterioles. Apelin is an endogenous ligand of the human orphan G-protein- coupled receptor APJ [34,35]. Apelin exerts a variety of cardiovascular effects and particularly acts as an activator of angiogenesis [36–39]. A recent study also reported that the apelin/ APJ system was involved in the regulation of blood vessel diameter during angiogenesis [40]. Our present data also demonstrated that treatment with Ad-Ang-1 significantly increase apelin expression. These data suggest potential role of Jagged1/Notch3 and apelin in Ang-1-mediated angiogenesis. Most intriguingly, overexpression of Ang-1 increases the number of BM-SMA+ cells as well as Ang-1+/ SMA+ cells in the diabetic infarcted hearts, suggesting that Ang-1 over-expressing SMA+ cells in the BM may also be recruited to the ischemic myocardium rather than their homing to Ang-1+ cells in the heart itself. Recruited CD45+ cells represent a rich source of hematopoietic stem cell cytokines in the ischemic heart.[41] Our data showed that CD45+ cells were dramatically increased in diabetic infarcted hearts after Ad-Ang-1 treatment. Furthermore, the abundance Tie-2-expressing CD45+ cell was increased implying that these cells may contribute to the Ang-1-mediated angiogenic response in diabetic infarcted hearts. Our data also demonstrate that over- expression of Ang-1 significantly increased BM-derived CD31+ cells and upregulated VEGF expression in BM. Recent studies showed that BM-CD31+ cells were enriched with remarkably higher levels of angiogenic and hematopoietic genes as compared to BM-CD312 cells. Furthermore, BM-CD31+ cells induced the activation of angiogenic, anti-apoptotic and chemo-attractant factors in ischemic hind-limbs via a paracrine effect. Trans- References 1. Suri C, Jones PF, Patan S, Bartunkova S, Maisonpierre PC, et al. 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