Objective: To investigate the isolation and expansion of mesenchymal stem cells (MSCs) from human umbilical cord Wharton's jelly and their biological identities, and explore the possibility of inducing human umbilical cord-derived MSCs to differentiate into neurocyte-like cells.
Methods: The growth and proliferative abilities of human umbilical cord-derived MSCs were observed, and their immunophenotypes were determined by flow cytometry. Salvia miltiorrhiza and beta-sulfhydryl alcohol were adopted to induce the cells to differentiate. The differentiated and undifferentiated cells were identified with immunocytochemistry. The pleiotrophin and nestin genes were measured by RT-PCR.
Results: A population of human umbilical cord-derived MSCs were isolated from human umbilical Wharton's jelly; they were processed to obtain a fibroblast-like population of cells and could be maintained in vitro for extended periods with stable population doubling, and they were expanded as undifferentiated cells in culture for more than 10 passages, indicating their proliferative capacity. The human umbilical cord-derived MSCs were positive for CD(29), CD(44), CD(59), CD(105), but negative or weakly expressed the markers of hematopoietic cells such as CD(14), CD(33), CD(34), CD(28), CD(45) and CD(117). The important GVHD correlation markers were negative or weakly expressed, including CD(80) (B7-1), CD(86) (B7-2), CD(40) and CD(40L). Salvia miltiorrhiza beta-sulfhydryl alcohol could induce the MSCs to express nestin, a marker of neuronal precursor stem cells at early stage of differentiation. Later, they exhibited neural phenotypes, expressing beta-tubulin III and neurofilament (NF) and glial fibrillary acidic protein (GFAP). It was confirmed by RT-PCR that the MSCs could express pleiotrophin either before or after the induction of salvia miltiorrhiza, furthermore, after the induction the expression was markedly enhanced and the nestin gene was also expressed.
Conclusion: The human MSCs could be isolated from human umbilical cord Wharton's jelly, and it was easy to propagate these MSCs. The negative GVHD correlated markers might result from the fact that MSCs had no HLA barrier, which may suggest potential clinical significance. The MSCs are capable of differentiating into neurocyte-like cells and they may represent an alternative stem cell source for CNS cells transplantation.