Abstract: AIM: The preclinical study was designed to test the feasibility and safety of autologous bone mesenchymal stem cell (MSC) transplantation by intracoronary injection in pigs with acute myocardiac infarction. METHODS: Coronary obstruction with balloon was used to produce acute myocardial infarction (AMI).Labeled MSCs were implanted by intracoronary injection.Four weeks later, single photon emission computed tomography was used to evaluate the relative infarct size.The myocardial ventricular systolic pressure (LVSP), left end-diastolic pressure (LVEDP), peak of pressure rise (LV+dp/dt_max) and peak rate of pressure fall (LV-dp/dt_min) were assessed by catheterization.Immunofluorescence was performed to evaluate MSC engrafment and differentiation. RESULTS: Compared with control group, heart function parameters were all improved in pigs receiving MSCs transplantation, including EF [(44.1±4.3)% vs (39.0±5.2)%, P<0.05] perfusion score [(30.0±5.3) vs (41.8±8.8), P<0.01], relative infarct size [(28.6±4.7)% vs (33.5±3.4)%, P<0.05], LVSP (87±9 mm Hg vs 78±4 mm Hg, P<0.05), LV+dp/dt_max [(1818±117) mm Hg/s vs (1611±115) mm Hg/s, P<0.01, 1 mm Hg=0.133 kPa], LV-dp/dt_min [(1801±89) mm Hg/s vs (1618±66) mm Hg/s, P<0.01] and LVEDP [(9.4±1.7) mm Hg vs (12.6±2.8) mm Hg, P<0.05].MSCs implanted in myocardium were stained positively for myosin heavy chain, connexin 43, smooth muscle actin and von Willebrand factor. CONCLUSION: These results demonstrate that transplantation of MSCs can improve cardiac function in AMI pig, and that the improvement might result from myocardial regeneration and angiogenesis by MSC differentiation.

Key words: bone marrow mesenchymal stem cell, acute myocardial infarction, stem cell transplantation