Influence of mesenchymal stem cells derived from bone marrow of children with oncohematological diseases on proliferation and self-renewal of hematopoietic progenitor cells in vitro.
OBJECTIVE
To test the ability of cultured mesenchymal stem cells (MSCs) from bone marrow (BM) of children with oncohematological diseases after chemotherapy and radiation to support proliferation and self renewal of hematopoietic cells in vitro.


METHODS
BM samples of 8 patients and 9 healthy children-donors used for MSCs preparation applying technique of expansion in vitro. CD34+ cells were isolated from BM of donors. The ability of MSCs to maintain hematopoietic stem cells (HSCs) proliferation was tested in semisolid methylcellulose medium and in liquid long-term-culture (LTC) medium.


RESULTS
The presence of MSCs derived from BM of patients in methylcellulose medium induced 2-fold increase of the number of committed myeloid progenitors without cytokines, 7-fold increase together with growth factors and 14-fold increase of the amount of earlier pluripotent hematopoietic precursor cells (CFU-GEMM) compared to expansion of HSCs without MSCs and cytokines. The presence of MSCs layer of patients in liquid LTC medium significantly promoted the hematopoietic cells proliferation rate, measured on 7th, 14th and 21st day. The total number of cells was multiplied 161.2-fold on 21st day as compared to 116.4-fold without MSCs layer. In the presence of MSCs layer, we detected the increase of proportion of bipotent CFU-GM precursors from 4% to 11% and pluripotent CFU-GEMM precursors from 0.1% to 0.6% in population of HSCs. In both types of experiments the capacity of patients' MSCs to support HSCs proliferation and self renewal was the same as for healthy donors' MSCs.


CONCLUSIONS
In this study, MSCs were isolated from BM of children with malignancies after high-dose chemotherapy or radiation. The ability of these MSCs to maintain hematopoiesis in vitro was tested. It was shown that co-transplantation of autologous MSCs is a good way to improve hematopoietic stem cells engraftment and reduce a period of granulocytopenia after autologous HSCs transplantation in case of insufficient CD34+ cell number in autologous transplant.
Belarusian Research Centre for Pediatric Oncology and Hematology, Minsk, Belarus. yaninai@mail.ru
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D018952:Antigens, CD34 / Q000096:biosynthesis; D001853:Bone Marrow / Q000378:metabolism; D001854:Bone Marrow Cells / Q000166:cytology* / Q000378:metabolism; D018929:Cell Culture Techniques / Q000379:methods*; D002454:Cell Differentiation; D049109:Cell Proliferation; D002648:Child; D016207:Cytokines / Q000378:metabolism; D019337:Hematologic Neoplasms / Q000378:metabolism*; D006412:Hematopoietic Stem Cells / Q000166:cytology*; D006801:Humans; D059630:Mesenchymal Stem Cells / Q000166:cytology* / Q000378:metabolism; D013997:Time Factors
D018952:Antigens, CD34; D016207:Cytokines