Isolation of mesenchymal stem cells from human umbilical cord blood and its bone inducing activity in vitro

PURPOSE: To investigate the biological characters of mesenchymal stem cells obtained from human umbilical cord blood(HUCB-MSCs), and detect the influence of different serum concentrations of culture medium to primary HUCB-MSCs' growth kinetics and the osteogenic differentiation capacity of the passage cells.

METHODS: The mononuclear cells were isolated from umbilical cord blood(UCB), the growth characters and morphology of the primary MSCs were observed. Primary cells were cultured in alpha-MEM with different serum concentrations, and immunophenotype was investigated. P3 cells were induced to osteoblast-like cells and the differentiation results were analysed. SPSS 16.0 software package was used for statistical analysis through repeated measures analysis of variances.

RESULTS: Four subpopulations with different morphology could be distinguished in primary HUCB-MSCs. All the subpopulations were positive for CD44 and CD105, and negative for CD34 and CD45. HUCB-MSCs displayed faster and stable growth when cultured in alpha-MEM containing 15% serum. Passage cells of HUCB-MSCs could be induced into osteoblast-like cells, the formation of mineralized extracellular matrix and the positive staining of expression of ALP could be observed.

CONCLUSIONS: HUCB-MSCs are high in viability but low in proliferation. HUCB-MSCs contain 4 subpopulations with different morphology. The appropriate concentration of serum in culture medium should be 15%. HUCB-MSCs could be induced into osteoblast-like cells in vitro.