Abstract:

BACKGROUND: Nuclear magnetic resonance imaging shows unique advantage in cell tracking in vivo due to its long effective image displaying, high spatial and time resolution and good contrast.
OBJECTIVE: To investigate an appropriate concentration of superparamagnetic iron oxide (SPIO) that can be used to label human umbilical cord mesenchymal stem cells, and to tract in vivo the labeled stem cells in canine with acute myocardial infarction by magnetic resonance imaging system.
METHODS: Fresh human umbilical cords were obtained from full-term birth in sterile condition. Umbilical cord mesenchymal stem cells (UC-MSCs) from Wharton's Jelly were isolated and cultured. Passage 3 UC-MSCs were labeled with different concentrations of SPIO. Myocardial infarction was induced in an open chest canine model by artery occlusion and confirmed by electrocardiogram and histopathological findings. The UC-MSCs labeled or unlabeled with SPIO were transplanted into canines (experimental group, n=8; control group, n=4). Serial magnetic resonance imaging was performed before and 7, 28 days after transplantation. Histopathological observation was performed at 14 and 28 days.
RESULTS AND CONCLUSION: Over 90% of isolated UC-MSCs expressed CD29, CD44, and CD105 but not the hematopoietic lineage markers (CD34, CD45). Nearly 100% of UC-MSCs could be effectively labeled by SPIO at a concentration of 14-84 mg/L without influences on cell proliferation and activity. Electrocardiogram and histopathological detection suggested that myocardial infarction was successfully induced. Remarkable low signal change was clearly observed in the transplanted location through magnetic resonance imaging and paralleled in the same direction with myocardial cells. Therefore, the UC-MSCs can be effectively labeled by SPIO at a concentration of 14-84 mg/L, and the labeled UC-MSCs can also be monitored in vivo by magnetic resonance imaging after transplantation.