Characterization of Cultured Mesenchymal Stromal Cells Established from Human Chorion

Chorion is the outer fetal membrane around embryo that develops from the trophoblast and the underlying mesenchyme. The objective of this work was to characterize cell lines obtained from chorion of different donors. The expression profile of surface CD markers in three lines derived from three different donors was typical for human mesenchymal stromal cells (MSCs). During long-term cultivation, the cells retained a fibroblast-like morphology. In passages 4–5, the dynamics of the cell cycle was typical of that for normal human cells of mesenchymal origin. Increased cell number in phases of DNA synthesis and mitosis during the logarithmic growth phase subsequently decreased with cell density. In passages 6–7, the pattern of cell cycle distribution altered: cell number in the DNA synthesis phase decreased. Cells accumulated in the G2/M phase and polyploids number >2n increased. Flow cytometry showed a rapid decrease in the proliferative activity of the cells during their passaging. The population doubling time for one line cell was 40 h in passages 4–5 and increased by passages 6–7 to 52 h. For the other two lines, the doubling time was 80 h in passages 4–5 and the cells died after passages 6–7, ELISA revealed a significant level of VEGF secretion. Karyological analysis showed that chorionic cells in culture have a near-diploid karyotype prone to breakdown of chromosome material. These results show that chorionic MSC are not a reliable object both for use in laboratory studies with lengthy experiments and transplantation for regenerative medicine. However, a high level of VEGF factor secretion makes these cells as a possible source of conditioned medium for therapeutic purposes.