Stem cell homing and angiomyogenesis in transplanted hearts are enhanced by combined intramyocardial SDF-1α delivery and endogenous cytokine signaling

We used a heterotopic transplanted working heart model to probe the collaborative role of bone marrow-derived progenitor cells (BPCs) and stromal cell-derived factor (SDF)-1α in attenuating tissue remodeling in recipient and transplanted hearts. BPCs from male transgenic rats expressing green fluorescent protein (GFP+ BPCs, 2 × 106 cells) were injected intravenously into myeloablated female rats. One month later, heterotopic heart transplantation was performed. The left anterior descending coronary artery (LAD) of the recipient heart was occluded permanently. Mesenchymal stem cells (MSCs; 2 × 106 cells) with a null gene (null group) or overexpressing SDF-1α (SDF-1α group) were injected intramyocardially in the LAD perfusion region of both recipient and transplanted hearts. Recipient and transplanted hearts (n = 10 hearts/group) were harvested 21 days later for analysis. The survival of transplanted hearts was assessed daily by palpation in additional animals (n = 7). Five days after LAD occlusion, subpopu...