Synergistic effect of adipose-derived stem cell therapy and bone marrow progenitor recruitment in ischemic heart

Human multipotent adipose-derived stem cells (hMADSCs) have recently been isolated featuring extensive expansion capacity ex vivo. We tested the hypothesis that hMADSC transplantation might contribute to cardiac functional recovery by its direct or indirect effect on myocardial infarction (MI). Nude rats were either transplanted with hMADSCs or PBS (control) in ischemic myocardium immediately following MI. Echocardiographical assessment of cardiac function after MI with hMADSCs showed significant improvement of each parameter compared to that with PBS. Histological analysis also showed significantly reduced infarct size and increased capillary density in peri-infarct myocardium by hMADSC treatment. However, remarkable transdifferentiation of hMADSCs into cardiac or vascular lineage cells was not observed. Despite the less transdifferentiation capacity, hMADSCs produced robust multiple pro-angiogenic growth factors and chemokines, such as vascular endothelial growth factor (VEGF), basic fibroblast growth factor (bFGF), and stromal cell-derived factor-1α (SDF-1α). Specifically, hMADSC-derived SDF-1α had a crucial role for cooperative angiogenesis, with the paracrine effect of hMADSCs and Tie2-positive bone marrow (BM) progenitor recruitment in ischemic myocardium. hMADSCs exhibit a therapeutic effect on cardiac preservation following MI, with the production of VEGF, bFGF, and SDF-1α showing paracrine effects and endogenous BM stem/progenitor recruitment to ischemic myocardium rather than its direct contribution to tissue regeneration.