**5. Conclusions**

232 Liver Regeneration

Fluorescent imaging is based on the fluorescence property of a widely used protein such a green fluorescent protein (GFP) that is also introduced into the transplanted cells for stable expression [110]. Due to the low tissue penetrance and non-specific background generated by the autofluorescence of the surrounding tissue GFP reporter cannot be used to reliably

Imaging in the near-infrared (NIR) wavelength (700–900 nm) spectrum can maximize tissue penetrance in addition to minimizing the autofluorescence from non target tissue. Our lab is currently working on tracking transplanted cells using the fluorescent dye Di-D. EpCAM +ve human fetal liver cells were labeled with Di-D and injected in the liver of nude mice to monitor their survival and engraftment of the liver. Using Di-D the labeled cells were imaged with KODAK Fx PRO animal imaging system at various time points indicating the persistence of fluorescencent labeled EpCAM+ve cells upto 110 days post transplantation (Figure 5). The fluorescence images of animal were overlaid with the X-ray images of the animal. Further studies on the safety and efficacy of the dye needs to be confirmed before

Fig. 5. *In vivo* images of nude mice after intra hepatic transplantation with DiD labeled

Non-invasive tissue imaging methods to detect fibrosis play an important role in the management of liver disease. Methods to monitor the disease progression are as important as the treatment procedures, as timely detection of fibrosis could help in prevention of the

**4.2 Need for more non- invasive tissue imaging methods to monitor disease** 

EpCAM +ve cells at different time points (Unpublished data)

**progression** 

track *in vivo* characteristics of transplanted stem cells [109-112].

clinical trials could be attempted.

Cell based treatment is a promising area which is slowly gaining importance as a therapeutic approach for liver diseases. Preclinical and clinical trials with different types of adult cells have provided evidence for their usefulness in treating cirrhotic liver disease though with certain limitations. Recently, human fetal progenitor cells with their low immunogenicity and a good proliferative capacity are emerging as safe and potential sources for treating liver diseases. However, the efficiency of these cells in treating various types of liver diseases is yet to be established. Long term monitoring of the fate of the transfused cells also remains a challenging area that needs to be addressed before these cells can be used as routine treatment options for liver diseases. Improvised methods of cell isolation and infusion in patients and the development of faster and efficient non-invasive methodologies for detecting fibrosis at early stages would be an important step towards the management of liver diseases.
