Effects of human mesenchymal stem cells and fibroblastoid cell line as feeder layers on expansion of umbilical cord blood CD34(+) cells in vitro / 中国实验血液学杂志

ABSTRACT

To investigate the effects of human mesenchymal stem cells (MSC) and human fibroblastoid cell line (HFCL) as feeder layer on expansion of umbilical cord blood CD34(+) cells in vitro, (60)Co gamma-ray irradiated MSC and HFCL were used as feeder layer to expand cord blood CD34(+) cells in culture. The efficiencies of MSC and HFCL on expansion of CD34(+) cells in culture with or without cytokines were compared. The results showed that no matter whether cytokines (rhFL, rhSCF, rhTPO) were added, the proliferation of nucleated cells after expansion for 12 days in HFCL group was statistically higher than that in MSC group, i.e. with cytokines (9797 +/- 361)% vs (7061 +/- 418)%; without cytokines (5305 +/- 354)% vs (1992 +/- 247)%, when the cell numbers at day 0 was accounted as 100%), P < 0.01. The proliferation of propagated CD34(+) cells between MSC group and HFCL without addition of cytokines was not statistically different (820 +/- 191)% vs (825 +/- 305)%, P > 0.05. However, in the presence of cytokines, the propagating rate of MSC group was lower than that of HFCL group (939 +/- 212)% vs (1617 +/- 222)%, P < 0.01. MSC was better than HFCL in maintaining the LTC-IC of UCB CD34(+) cells, i.e. the number of CFU-GM colonies in the fifth week was (129.95 +/- 8.73) /10(5) seeded cells vs (89.81 +/- 10.29) colonies/10(5) cells, P < 0.05; with addition of cytokines, the effect was more obvious, i.e. the number of CFU-GM colonies in the fifth week (192.93 +/- 4.95)/10(5) seeded cells vs (90.47 +/- 14.28) colonies/10(5) seeded cells, P < 0.01. MSC mixed with a certain proportion of HFCL facilitated maintaining the LTC-IC of UCB CD34(+) cells. When the proportion was 41, the number of CFU-GM colonies was the highest (186.89 +/- 11.11)/10(5) seeded cells, which was higher than that of both 32 group [(138.92 +/- 14.84) colonies/10(5) seeded cells] and MSC only group, i.e. (64.63 +/- 6.11) colonies/10(5) seeded cells, both P < 0.01. It is concluded that HFCL is better than MSC in maintaining the expansion of CD34(+) cells and cytokines can enhance this effect, while MSC are stronger than HFCL in maintaining the LTC-IC of UCB CD34(+) cells in vitro. MSC with addition of a certain proportion of HFCL can significantly enhance the efficiency of CD34(+) cell expansion.