【Objective】 To investigate the feasibility of in vivo serial tracking of superparamagnetic iron oxide (SPIO)-labeled mesenchymal stem cells (MSC) for treatment of acute myocardial infarction (AMI) in swine. 【Methods】 After isolated by density gradient centrifugation

autologous MSC were transfected with green fluorescent protein (GFP) by lentiviral vector and labeled by SPIO. An AMI model was established by percutaneous balloon occlusion. Dual-labeled MSC were traced using serial MRI after 24 h

3 weeks

and 8 weeks of intracoronary transplantation into the MI area in swine. 【Results】 We demonstrate that when MSC were labeled with SPIO (25 µg Fe/mL plus 0.8 µL/mL lipofectamine) the labeling efficiency was 95%-100%

with no effects on GFP expression. Additionally

labeled MSC maintained the ability to differentiate into osteoblasts and adiptoblasts. Hypointensities detected in the interventricular septum were different from the surrounding tissue after 24 h

3 weeks

and 8 weeks of intracoronary transplantation. Both Prussian blue- and fluorescence-positive cells were histologically detected in the border zone of the MI area. 【Conclusion】 MSC labeled with SPIO showed optimum MRI signal intensity and tracer time. These findings demonstrate the feasibility of in vivo dynamic tracing of SPIO labeled MSC for the treatment of MI in swine.