Characterization of Human Umbilical Cord Mesenchymal Stem Cells after Long-Term Expansion

The purpose of this study is to evaluate the effects of long-term in vitro expansion on the stability and functions of human umbilical cord mesenchymal stem cells (hUC-MSCs). The hUC-MSCs were isolated from Wharton’s jelly and in vitro cultured till passage 20. The hUC-MSCs at passage 5， 10， 20 were selected to compare their proliferation capacity， immunophenotype， genomic stability， multi-differentiation potency， telomerase activity and senescence. Proliferation capacity of the hUC-MSCs at passage 5， 10， 20 remained no significant change. Long term expansion of hUC-MSCs had no effect on their immunophenotype determined by expression levels of the cell surface markers， karyotype and chromosomal microarray analysis showed genomic stability， and hTERT expression showed similar telomerase activity. Furthermore， the multi-differentiation potency of the hUC-MSCs still remained strong after long-term culture， demonstrated by adipogenic and osteogenic induction. However， an increase of senescence- associated β-galactosidase activity was observed over time. All the major biological characters and functions of hUC-MSCs remain unchanged after long-term in vitro expansion. However， hUC-MSCs cultured over 10 passages may have a reduced cell activity due to increasing senescence， therefore， hUC-MSCs cultured less than 10 passages are suitable for clinical research/therapy.

CSTR: 32200.14.cjcb.2019.01.0005