Factors influencing yields of mesenchymal stem cells derived from human umbilical cord blood / 中国组织工程研究

ABSTRACT

BACKGROUND: Mesenchymal stem cells (MSCs) exist in umbilical cord blood (UCB), currently, there is not a method to in vitro separate, culture and amplificate human UCB-MSCs effectively. OBJECTIVE: To explore factors that influence yields of UCB-MSCs. METHODS: The relationship between the success rate of yielding UCB-MSCs and several factors, such as gestational ages (≥40 weeks, 37 weeks and ≤32 weeks), the number of mononuclear cells (MNCs) in UCB (≥2.5×109/L, <2.5×109/L), the inoculum density of MNCs (1×107, 1×109, 1×1011/L), the concentration of fetal bovine serum (FBS, 5%, 10%, 15%, 20%) in culture medium, and whether the culture flask being coated with FBS or not beforehand, as well as relationships among these factors were investigated. RESULTS AND CONCLUSION: The success rate of yielding UCB-MSCs was up to 58.3%. The success rate decreased as the gestational ages increasing (P < 0.01). The success rate could be enhanced to 76.9% when the MNCs count was more than 2.5×109/L, and there was significant difference when comparing to that of the group (36.4%) with MNCs count less than 2.5×109/L (x2=8.07, P=0.005). There was a negative correlation between the MNCs count and the gestational ages in the specimens with the same volume of UCB (r=-0.95, P < 0.01). In the group with the cell inoculum density of 1×1011/L, the growth and proliferation of primary and subculturing MSCs were better than that of the groups with the cell inoculum density lower than 1×1011/L. The adherence of MSCs in the group with the culture medium containing 5% FBS happened much later than other 3 groups, while the purity of MSCs in this group was much higher. When comparing the passage rate, there was no significant difference among the 4 groups with different concentration of FBS. In the group of culture flask being coated with FBS beforehand, the purity and proliferation ability of MSCs was higher than that in the groups with culture flask not being coated. It is suggested that culture of UCB-MSCs was influenced by several factors. The success rate could be increased by choosing the fetus with relative lower gestational ages, collecting enough volume of UCB, inoculating cells with a higher density, choosing the medium with lower concentration of FBS, and coating the culture flask with FBS beforehand.