Potential feasibility of early bone marrow cell injection into the spleen for creating functional hepatocytes

Background. Bone marrow cells (BMCs) are believed to have the ability to generate functional hepatocytes and have some merits as a therapeutic modality for metabolic liver diseases. However, the appearance of BMC-derived hepatocytes (BMDHs) is low. We hypothesized that early BMC injection would be feasible for creating BMDHs for two main reasons: (1) the liver is a hematopoietic organ in neonatal rats and (2) it may allow sufficient time to generate more BMDHs before severe liver injury occurs. Methods. We used Long Evans Cinnamon (LEC) rats as recipients, a model of (1) Wilson disease and (2) liver carcinogenesis. Green fluorescent protein-expressing BMCs were injected into newborn LEC rats through the spleen. The oxidative activity of ceruloplasmin, which is low in LEC rats, was measured to evaluate the treatment. In addition, we performed fluorescence in situ hybridization to clarify the origin of the BMDHs and immunohistochemical analysis to confirm whether these BMDHs had malignant potential. Results. At 18 months after injection, we found some green fluorescent protein-expressing areas macroscopically in the liver of treated LEC rats. The oxidative activity of ceruloplasmin increased in treated LEC rats (n=7) and were much higher than that in untreated LEC rats (P=0.015). Moreover, we confirmed that the BMDHs were generated by cell fusion and was not detected in any of the neoplastic lesions or cholngiofibrotic regions. Conclusion. Our results suggest that this novel strategy for creating BMDHs is effective and safe.