Autologous in vitro expanded mesenchymal stem cell therapy for human old myocardial infarction.

Stem cell transplantation after myocardial infarction has been claimed to restore cardiac function. Mesenchymal stem cells attract a lot of attention because of the feasibility of in vivo and ex vivo differentiation to cardiomyocytes and endothelial cells as well as their trophic effect on tissue repair. In this study, we investigated the efficacy of autologous bone marrow derived mesenchymal stem cells in improving heart function in patients with old myocardial infarction.Eight patients with old myocardial infarction and proper inclusion criteria were injected with mesenchymal stem cells at the time of coronary artery bypass grafting or percutaneous coronary intervention (test group) and compared with eight matched patients who received the same treatment without mesenchymal stem cell injection (control group). Evaluation of heart function was done by echocardiography plus single-photon emission computed tomography before and six months after the procedure. Serial clinical examination was performed every month through New York Heart Association class.The mean New York Heart Association class and single-photon emission computed tomography scan results decreased significantly in the test group (P=0.000 and 0.002, respectively) and in the control group (P=0.049 and 0.007, respectively) after the procedure at six months follow-up. Left ventricular ejection fraction increased significantly in the test group (P= 0.005) but not in the control group. In comparison between the test and control groups the results of New York Heart Association class assessment and single-photon emission computed tomography demonstrated significant improvement in the test group (P=0.005 and 0.013, respectively). There were no significant differences between the baseline variables in the two groups.Transplantation of ex vivo expanded bone marrow derived mesenchymal stem cell in patients with old myocardial infarction is a safe and feasible procedure. These cells improve the cardiac function without serious adverse effects.