Biological, immunological and regenerative characteristics of placenta-derived mesenchymal stem cell isolated using a time-gradient attachment method.

It has been verified that placenta contains multi-lineage mesenchymal stem cells (MSCs). We have used a time-gradient attachment method to isolate placenta-derived MSCs (PMSCs). The morphology, differentiation potential, immunogenicity and xenogenic reconstruction potential of these PMSCs were examined. The results showed that PMSCs isolated using the time-gradient attachment method showed higher potential of in vitro proliferation and multi-lineage differentiation. PMSCs isolated using the time-gradient attachment method showed a low immunogenicity. HLA-A gene fragment and no HLA-DR gene fragment were detected in PMSCs isolated using the time-gradient attachment method, and the mixed lymphocyte reaction (MLR) assay identified that these cells inhibited the proliferation of the allogeneic T-lymphocytes induced by PHA. The transplantation in calvaria of rats showed that PMSCs had the higher xenogenic reconstruction potential. Finally, the significance of PMSCs isolated using the time-gradient attachment method in experimental and clinical applications is discussed.