Growth kinetics and self-renewal of human mesenchymal stem cells derived from bone marrow of children with oncohematological diseases during expansion in vitro.

AIM: We investigated the ability of mesenchymal stem cells (MSCs) derived from bone marrow (BM) of children with oncohematological diseases after chemotherapy and radiation therapy to the self-renewal and proliferation for further expansion and their implementation as co-transplant, together with autologous hemopoietic stem cells (HSCs).

MATERIALS AND METHODS: BM samples from 20 patients with tumors and BM samples from healthy children-donors (for allogenic HSCs transplantation) were under study. The colony forming unit-fibroblast (CFU-F) assay and the colony forming unit-granulocytes and macrophages (CFU-GM) assay were used for the evaluation of MSCs and HSCs proliferative capacity. Mononuclear cells (MNCs) were plated 1 x 10(6). Following 14 days cells subcultured in primary culture (I passage) to study MSCs ability to self-renewal in culture. 6 passages were performed. The population doubling (PD) in each passage and the cumulative population doubling were calculated.

RESULTS: Data revealed 3-4-fold reduction of the mean incidence of CFU-F in patients after treatment compared to donors. The number of CFU-GM in patients was lower than in donors as well (39.0, 9.0-130.0 vs 95.0, 31-205). Correlation between numbers of CFU-F and CFU-GM was revealed in patients BM (r = 0.63, p < 0.003) as well as in healthy children. MSCs from BM possessed high potential to self-renewal. Their number increased 900-fold in primary cultures in the first 14 days and 17-fold in subculture in 60 days. The analysis of cumulative PD in patients and donors demonstrated the slowing of cell proliferation and telomere length decrease from passage to passage.

CONCLUSION: Despite the low content MSCs from BM of children with oncohematological diseases possessed high potential to self-renewal. The total number of MSCs can be increased 1.5 x 10(4) fold in 2 months period in vitro.