Effect of transplantation with autologous bone marrow stem cells on acute myocardial infarction

This study was designed to investigate the effects of treatment with autologous mesenchymal stem cells (MSCs) by intracoronary transplantation on myocardial infarction (MI) in swine.

MSCs were transfected with a lentiviral vector carrying the gene encoding green fluorescent protein (GFP) and labeled in vitro with superparamagnetic iron oxide (SPIO). An acute MI (AMI) model was established by percutaneous balloon occlusion. Dual-labeled MSC suspensions were injected through the infarct-related coronary artery using an over-the-wire (OTW) balloon device in the experimental group (n=5), while normal saline was injected into the control (n=5). Stem cell migration and improvements of cardiac function were evaluated by magnetic resonance imaging (MRI), single-photon emission computed tomography (SPECT), and ultrasonic cardiogram (UCG) both before MSC transplantation and after 8 weeks. At 8weeks after transplantation, myocardial tissue was analyzed by histopathologic analyses.

Blue SPIO particles were in the cytoplasm of the MSCs. The labeling efficiency reached 100%. MRI revealed hypointensities of SPIO-labeled MSCs that were clustered in the myocardial infarct area after MSC transplantation. As time progressed, the signal gradually weakened and the area shrank. SPECT revealed that the myocardial filling defect was reduced and the amount of surviving myocardium was significantly increased at 8weeks. UCG revealed significant improvement when compared with the control at 8 weeks after transplantation. Prussian blue-positive cells were observed in the MI border zone. Fluorescence-positive cells were also observed, but the number of such cells was fewer than before.

In vivo serial tracking of SPIO-labeled MSCs can be achieved by MRI. Intracoronary transplantation of SPIO-labeled MSCs can increase cardiac function and promote myocardial viability.