The Derivation and Comparative Characterization of Mesenchymal Stem Cell Lines, Isolated from Human Pulp of a Deciduous Tooth of Children of Different Sexes

Abstract

Two new non-immortalized fibroblast-like cell lines isolated from the pulp of Deciduous Tooth of Children of Different Sexes, named MSC-DP-1 and MSC-DP-2, were derived and characterized. In order to confirm the status of mesenchymal stem cells, a comparative analysis of a some characteristics in these lines was carried out at early and late passages. In the process of long-term cultivation, significant interline differences were revealed in the nature of replicative senescence (RS) and in growth characteristics. The MSC-DP-1 line was characterized by a later entry into the active stage of RS and more active proliferation compared to the MSC-DP-2 line. Karyotypic analysis showed that both lines have a normal human diploid karyotype at early passages. At the late (18th passage), in the stage of active PS, the MSC-DP-2 line also has a normal karyotype. And the MSC-DP-1 line, which enters the active stage of RS much later (at passage 42), has an abnormal karyotype with a large number of clonal chromosomal rearrangements. Both lines showed a high proportion of cells carrying antigens characteristic of human MSCs: CD44, CD73, CD90, CD105, HLA-ABC, and a low frequency of cells with CD34, CD45, and HLA-DR antigens. The cells of the derived lines at an early passage have the ability to differentiate in adipogenic, osteogenic and chondrogenic directions. But the MSC-DP-2 line shows weaker differentiation in the adipogenic direction, than the MSC-DP-1 line. In the process of RS, a significant weakening of adipogenic differentiation takes place in the MSC-DP-1 line, and it disappears in the MSC-DP-2 line. The activity of other differentiations does not change during RS. In general, the derived results confirm the status of MSCs for the derived lines and indicate interline differences in the RS process. However, the derived differences between these lines, as well as the comparison with the previously derived line MSC-DP do not indicate their gender nature. Apparently, they are associated with the genetic characteristics of different donors.