BACKGROUND: Hematopoietic stem cells of the human fetal liver prior to 15 weeks gestation have remakable advantages for successful engraftment due to embryological immune immaturity, especially in-utero transplantation. This study was undertaken to obtain objective assessment data about the possibility of fetal liver hematopoietic stem cell transplantation un the future.
METHODS: Six cases of the fetal liver tissue were obtained from therapeutic abortions at 12∼20 weeks gestation. The fetal liver was collected in RPMI media containing 10% fetal calf serum and the cell suspensions were obtained by centrifugation following physical disruption. The number of nucleated cells in each case was counted and the colony numbers in methyl cellulose media were scored according to incubation period with or without growth factors. Some of the cells were cryopreserved in the liquid nitrogen tank, thereafter cell viability and colony numbers were evaluated according to cryopreservation period.
RESULTS: The nucleated cell numbers obtained from each fetal liver increased with gestational age. The colony numbers alter incubation increased with gestational age and the erythroid lineage was predominant in 3 cases welch are under 15 weeks gestation. The colonogenic activity after incubation with combination of hematopoietic growth factors increased in only one case. The cell viability and the colony numbers after cryopreservation was decreased compare to the value before cryopreservation.
CONCLUSION: The number of nucleated cells and hematopoietic stem cell colony formation were increased with gestational age and viability of the cells after cryopreservation was decreased. Further systematic studies using more cases would be needed to obtain objective assessment data for fetal liver transplantation program in the future.

Keywords: Fetal liver, Hematopoietic stem cell, Colony