Evaluation of iron oxide labeling as a tool for long term cell tracking and its effects on human dental pulp stem cell differentiation

Human dental pulp stem cells (hDPSCs) are considered plausible candidates for cell-based therapies and non-invasive imaging techniques are necessary to evaluate stem cell therapy. Magnetic labeling with superparamagnetic iron oxide (SPIO) particles, allows in vivo visualization using MRI. This study hypothesized that SPIO particles can be used for long-term in vivo monitoring of hDPSCs, without affecting their differentiation potential. SPIO labeling did not interfere with adipogenic or osteogenic differentiation as evidenced by respectively the co-localization of lipid droplets and SPIO-containing endosomes and the capacity of SPIO-labeled hDPSCs to produce extracellular matrix. In vitro MRI showed that both adipogenic and osteogenic induced SPIO-labeled hDPSCs were able to significantly decrease T2* signal intensity after three weeks of in vitro culture. Furthermore, subcutaneously injected labeled adipogenic induced hDPSCs were detected by in vivo MRI. These results show great promi