Long-term in vivo monitoring of adult-derived human liver stem/progenitor cells by Bioluminescence Imaging, PET and contrast enhanced CT.

Adult-derived human liver stem/progenitor cells (ADHLSCs) have the potential to alleviate liver injury. However, the optimal delivery route and long-term biodistribution of ADHLSCs remains unclear. In this paper, we used a triple fusion reporter system to determine the kinetic differences in the biodistribution of ADHLSCs following intrasplenic (IS) and intrahepatic (IH) administration in SCID-beige mice. ADHLSCs were transduced with a lentiviral vector expressing a triple-fusion reporter comprising renilla luciferase, monomeric red fluorescent protein and truncated HSV-1 thymidine kinase. The stability and duration of the transgenes, and the effects of transduction on the cell properties were evaluated in vitro. The acute retention and long-term engraftment in vivo were revealed by positron emission tomography (PET) and bioluminescence imaging (BLI), respectively, followed by histochemical analysis. We showed that ADHLSCs can be safely transduced with the triple fusion reporter. Radiolabeled ADHLSCs showed acute cell retention at the sites of injection. The IH group showed a confined BLI signal at the injection site, while the IS group displayed a dispersed distribution at the upper abdominal liver area, and a more intense signal. In conclusion, ADHLSCs could be monitored by BLI for up to 4 weeks with a spread out biodistribution following IS injection.