MRI assessment of acute myocardial infarction with transplantation of autologous mesenchymal stem cells in swine: an experimental study

Objective: To investigate the effects of autologous bone marrow-derived mesenchymal stem cells (MSCs) transplantation on acute myocardial infarction in swine models using MRI. Methods: Fourteen Chinese mini-pigs (27 ± 3 kg) were divided into control group (n=7) and transplantation group (n=7). Acute myocardial infarction (AMI) model was made by occlusion of the left anterior descending coronary artery for 90 minutes, and then 10 ml autologous MSCs (3 x 106 cell/ml) were injected into LAD by over-wire-balloon catheter after one week. MRI was performed to assess the cardiac function and myocardial perfusion 1 week after AMI and 6 weeks after transplantation. The implanted cells in vitro were analyzed by immunofluorescence. Results: The left ventricular ejection fraction (LVEF) in transplantation group was increased from (42.7±7.5)% to (50.1±10.1)%, which was significantly different from that in control group (P<0.01). In addition, the dyskinetic segments in infarcted region and the infarcted area were decreased by 4 and 3.2 cm2 respectively (P<0.O1), and the left ventricular weight index was increased by 4.1 g/m2 in transplantation group (P<0.05) compared with control group. The DAPI-labeled cells in infarcted and peri-infarcted region indicated the survived MSCs. Immunofluorescence also confirmed that those cells expressed cardiomyocyte-specific troponin T, connexin 43 and vessel-specific smooth muscle actin. Capillary density in both infarcted and peri-infarcted region were higher in transplantation group than the control group (P<0.01). Conclusion: MRI is a reliable imaging method for assessing the effects of stem cell transplantation in acute myocardial infartion of swine models. (authors)