Induced bone marrow mesenchymal stem cells improve cardiac performance of infarcted rat hearts

We investigated whether transplantation of bone marrow mesenchymal stem cells (BMSC) with induced BMSC (iBMSC) or uninduced BMSC (uBMSC) into the myocardium could improve the performance of post-infarcted rat hearts. BMSCs were specified by flow-cytometry. IBMSCs were cocultured with rat cardiomyocyte before transplantation. Cells were injected into borders of cardiac scar tissue 1 week after experimental infarction. Cardiac performance was evaluated by echocardiography at 1, 2, and 4 weeks after cellular or PBS injection. Langendorff working-heart and histological studies were performed 4 weeks after treatment. Myogenesis was detected by quantitative PCR and immunofluorescence. Echocardiography showed a nearly normal ejection fraction (EF) in iBMSC-treated rats and all sham control rats but a lower EF in all PBS-treated animals. The iBMSC-treated heart, assessed by echocardiography, improved fractional shortening compared with PBS-treated hearts. The coronary flow (CF) was decreased obviously in PBS and uBMSC-treated groups, but recovered in iBMSC-treated heart at 4 weeks (P < 0.01). Immunofluorescent microscopy revealed co-localization of Superparamagnetic iron oxide (SPIO)-labeled transplanted cells with cardiac markers for cardiomyocytes, indicating regeneration of damaged myocardium. These data provide strong evidence that iBMSC implantation is of more potential to improve infarcted cardiac performance than uBMSC treatment. It will open new promising therapeutic opportunities for patients with post-infarction heart failure.