Fetal Liver-Derived Stem Cells Ameliorate Immune Functions in Leptin Receptor-Deficient Mice

Fetal liver (FL) contains hepatic stem cells, hematopietic stem cells, and mesenchymal stem cells, as well as pluripotent stem cells and very small embryonic-like stem cells. FL has thus been available as a source of stem cells for regenerative medicine. Our previous report suggested that combining FL cell transplantation with the transplantation of fetal thymus prevented tumor growth in tumor-bearing mice. Moreover, in animal models, intra bone marrow-bone marrow transplantation (IBM-BMT) has proven to be the best approach for allogenic BMT. We here propose that transplanting FL cells by IBM-BMT can improve immune functions in leptin receptor-deficient (db/db) mice. FL cells were collected from FLs of C57BL/6 mice at 16 days post coitum, and then transplanted by IBM-BMT to leptin receptor deficent mice, an animal model of type 2 diabetes with obesity. Our results showed that the body weight was significantly lowered in the treated db/db mice than in the sham-treated db/db mice. The plasma IL-6 level significantly decreased and adiponectin level significantly increased after the transplantation of FL cells. Blood glucose levels also significantly decreased although not to within the normal range. This is the first report that the transplantation of FL cells may improve immune function, resulting in increased adiponectin levels, and decreased body weight in db/db mice.