Kinetics and functional assay of liver repopulation after human cord blood transplantation

Background and aims: To evaluate donor cell engraftment and the kinetics of cell repopulation in the injured mouse liver following human umbilical cord blood cell transplantation. Methods: Nonobese diabetic/severe immunodeficient mice were treated with allyl alcohol to induce liver injury. Twenty-four hours later, umbilical cord blood derived mononuclear cells were transplanted by intra-splenic injection. Mice were sacrificed from 1 to 180 days after transplantation. Temporal changes in the ratio of human cells and fluorescence counts of human sex-determining region Y alleles in mouse liver were determined to evaluate the kinetics of cell repopulation. Mouse liver and sera were examined for the presence of human albumin. Results: Human cell repopulation was extremely rapid in the first week following transplantation, with a doubling time of 1.16-1.39 days apparent. Thereafter cell doubling rate slowed significantly. Cells displaying characteristics of human hepatocytes were still evident at 180 days. Human albumin was detected in mouse liver and sera. Conclusion: These findings confirm those from previous studies demonstrating that cells derived from human umbilical cord blood have the capacity to differentiate into cells with human hepatocyte characteristics in mouse liver following injury. Moreover, the detailed information collected regarding the kinetics of human cell repopulation in mouse liver will be of relevance to future studies examining the use of umbilical cord blood cells in liver transplantation therapy. ? 2007 Editrice Gastroenterologica Italiana S.r.l.