Objective: To compare the efficacy of transplanting bone marrow mesenchymal stem cell (BMSC) or microenvironmental induced BMSC (iBMSC) into the ischemic myocardium of rats with myocardial infarction.
Methods: iBMSC was defined as BMSC co-cultured with myocardial cells for 2 weeks. The stem cells or equal volume PBS were injected into ischemic border zone 1 wk after experimental infarction. Cardiac performance was evaluated at 1, 2, and 4 wk after cell transplantation by echocardiography and analyzed histologically at 4 wk after cell transplantations.
Results: Compared with PBS group, both BMSC and iBMSC transplantations reduced infarct size. iBMSC enhanced the beneficial effects of BMSC on improving cardiac function (FS: 28.5% +/- 4.3% in PBS, 29.0% +/- 2.0% in BMSC and 45.1% +/- 3.1% in iBMSC group at 4 weeks post transplantation, iBMSC group vs. PBS group P < 0.05, iBMSC group vs. BMSC group P < 0.05). Immunofluorescence microscopy results revealed co-localization of SPIO-labeled transplanted cells with cardiac markers for cardiomyocytes, indicating regeneration of damaged myocardium.
Conclusion: Our data suggest that iBMSC implantation is more effective on improving cardiac function than BMSC implantation in this model. iBMSC might serve as a new promising therapeutic cell source for regenerating ischemic myocardium in patients with post-infarction heart failure.