Ex vivo expansion of megakaryocyte progenitor cells from human cord blood in serum-free culture / 中国实验血液学杂志

ABSTRACT

Prolonged thrombocytopenia is a puzzling problem following umbilical cord blood (CB) transplantation. It might be the result of inadequate megakaryocyte progenitors and the arrest in the megakaryocyte maturation. It is an important method to solve the problem by transfusing ex-vivo expanded CB megakaryocyte progenitor cells into the patients to shorten the duration of platelet recovery. However, the most optimal condition of expansion has not been established so far. In the study, cord blood mononuclear cells (MNC) were cultured in serum-free medium with TPO, IL-3, SCF and IL-6. The numbers of MNC, CFU-MK and CD41(+) cells were measured at 0, 6, 10 and 14 days, in order to find the best cytokine combination and optimal harvest time point for clinical use. The results showed that the megakaryocyte progenitors most efficiently expanded with the cytokine combination including TPO, IL-3, SCF and IL-6. The time point of maximal CFU-MK growth is day 10. At 10 days, the numbers of CFU-MK and CD41(+) cells expanded by 6.8- and 8.8-fold respectively. In conclusion, in vitro, the cytokine cocktail including TPO, IL-3, SCF and IL-6 was the most optimal cytokine combination which stimulates the ex vivo expansion of megakaryocyte progenitors in CB MNC and serum-free medium. The maximal CFU-MK colonies were harvested at 10 days, that may be an optimal harvest time for clinical transfusion.