[A two-phase culture system for megakaryocyte differentiation of human mobilized peripheral blood CD34+ cells]

In our study, a two-phase culture system was developed to acquire large amount of CD41+ and polyploidy cells. Human mobilized peripheral blood CD34+ (PB CD34+) cells were first cultured in expansion medium (Cocktail or CC100 medium) for 3,4,5 or 6 days, and then cultured in megakaryocytic differentiation medium containing TPO and SCF for additional 7, 8 or 9 days. Cell expansion, morphology, CD41+ cell percentage and DNA content were investigated to evaluate the protocol. The result showed that more CD41+ and polyploidy cells could be obtained following the two-phase culture with Cocktail medium than with CC100. Moreover, with 3 days expansion in Cocktail medium plus 7 days in differentiation medium, the initial CD 34+ cells obtained 16-fold expansion of CD41+ cells and 3-fold expansion of polyploidy cells, such obtained level being significantly higher than that of culturing cells with only one step in TPO or TPO+SCF. We conclude that with the two-phase culture system, PB CD34+ cells can expand and differentiate to more CD41+ and polyploidy cells than those cultured only in accordance to the one-stage culture protocol, so a new and highly efficient megakaryocyte differentiation model for megakaryocyte and platelet related researches is provided already.