Study On The Supportive Effect Of Human Amniotic Mesenchymal Stem Cells On Hematopoiesis In Vitro

[Objective] To explore the supportive effects of mesenchymal stem cells(MSCs) derived from human amnions on hematopoiesis in vitro and to promote the clinical applications of amniotic mesenchymal stem cells(AMSCs).[Methods]MSCs were isolated and cultured from human amnions after childbirth by the tissue pieces culture method. Mononuclear cells (MNC) were isolated from umbilical cord blood by Ficoll-Paque density gradient centrifugation (1.077g/L).CD34 positive cells were isolated by magnetic cell sorting. The MNC and CD34 positive cells were co-cultured with AMSCs for four weeks respectively. The concentration of the floating cells was recorded weekly. And as the control, they were co-cultured with the BM-MSC respectively as well. Two weeks later, the MNC and CD34 positive cells were plated in semisolid culture medium separately , and the colony formation was assessed 14-16 days after the plating. The types of colonies were identified as granulocyte/macrophage colonies (CFU-GM), erythroid burst-forming units (BFU-E), erythroid forming units(CFU-E), and erythrocyte-containing mixed colonies (CFUMix/CFU-GEMM) according to their typical morphological features.All analyses were performed by using SPSS16. Data were expressed as mean±standard deviation (SD). The significance of differences was determined by using One-Way ANOVA. A p value <0.05 was considered to be statistically significant.[Results] AMSCs had phenotype and morphology similar to MSCs derived from other tissue. Morphologically, these cells were spindle-shaped or polygonal. The flow analysis revealed that AMSCs highly expressed CD29, CD44, CD105, and they were negative for markers of endothelial, hematopoietic, and epithelial cells, i.e., CD31, CD34, CD45, pan-CK. AMSCs can promote the expansion of human cord blood mononuclear cells and CD34~+ cells, and also can promote the formation of hematopoietic progenitor cell colony. Its capacity of hematopoitic support was similar to that of BM-MSCs. [Conclusion] MSCs can be successfully isolated and expanded from amnions by the tissue pieces culture method. And in vitro AMSCs had the capacity for hematopoietic support similar to BM-MSCs. So they may be an ideal source of stem cells for the expansion of HSCs in vitro and the co-transplantation of MSCs and HSCs to improve the success rate of clinical transplantations.