[Effect of different hemopoietic microenvironment on the differentiation of hemopoietic cells from human embryonic stem cells].

Objective: To observe the inductive efficiency of deriving hematopoietic cells from human embryonic stem (hES) cells co-cultured with human yolk sac stromal cells, fetal liver stromal cells or fetal bone marrow stromal cells,in order to discuss the effect of the different hemopoietic microenvironment on hemopoietic cytogenesis.

Methods: We used two-step method to induce the hES cells into the hematopoietic cells. In the first step the hES cells were co-cultured with cytokines by formation of the day 5 embryoid bodies (5d EBs). In the second step the 5d EB cells were induced into the hematopoietic cells by co-culturing with human yolk sac stromal cells, fetal liver stromal cells or fetal bone marrow stromal cells for 10 days. The inductive efficiencies of deriving hematopoietic cells from hES cells co-cultured with the different hemopoietic microenvironment were reflected by the expression levels of flk, CD34 and CD45 antigen.

Results: Flow cytometry analysis demonstrated that the population of the cells co-cultured with human yolk sac stromal cells contained flk (1.80%+/-0.56%), CD34 (1.30%+/-0.14%) or CD45 (1.05%+/-0.63%) positive cells; the population of the cells co-cultured with human fetal liver stromal cells contained flk (34.00%+/-25.45%), CD34 (38.40%+/-24.80%) or CD45 (72.60%+/-25.70%) positive cells; the population of the cells co-cultured with human fetal bone marrow stromal cells contained flk (2.50%+/-1.48%), CD34 (3.20%+/-0.56%) or CD45 (1.65%+/-0.21%) positive cells. Compared with spontaneous differentiation of EBs, all of the three stromal cells could induce EBs into the hematopoietic cells (P<0.05).

Conclusion: The inductive efficiency of deriving hematopoietic cells from EBs co-cultured with human fetal liver stromal cells was higher than EBs co-cultured with human yolk sac stromal cells and fetal bone marrow stromal cells.