Biological Characteristations Of Hematopoietic Disorders Patients' Bone Marrow Mesenchymal Stem Cells

Stem cells are of great therapeutic potential because of their ability to self-renew and differentiate into multiple tissues. Stem cells have become the core of the research of life science. According to their origin, there are two kinds of stem cell: embryonic stem cells and adult stem cells. Embryonic stem cells derived from the inner cell mass and possess the potential to generate multiple somatic cell types and give rise to the embryoproper. The adult stem cells, which bear characters of self-renewed, proliferation and multi-differentiation potential, were isolated from fetal and postnatal tissues and organs. Although embryonic stem cells are of great therapeutic potential because of their ability of multi-differentiation and easily operated in vitro, the application of embryonic stem cells was limited by several problems, such as intangibly differatiation mechanism, potential tumor development, ethical concerns and so on. So, adult stem cells became the core of the research on stem cells. Recently, more and more studies focus on the research of mesenchymal stem cells. Mesenchymal stem cells are population that not only possess the abilities of multiple differatiation and hematopoiesis support, but also have the abilities of immunosuppressive property and immunoregulatory function, and may be an attractive tool for clinical needs. But, Do MSCs have some changes with certain disease processes? Do chemotherapeutic drug damage MSCs? and how to damage MSCs? Is there other stem cell population in granulocyte colony-stimulating factor mobilized peripheral blood? All these questions are our purposes to investigate in this paper. Part One: Isolation and Characteristation of HematopoieticDisorder Patients' Bone Marrow Mesenchymal Stem Cellsand Their Hematopoiesis SupportObjective To study the biological characteristics of mesenchymal stem cells (MSCs) derived from hematopoietic disorder patients' bone marrow, and examines their abilities of pluripotentiality and hematopoiesis support. Methods we have isolated MSCs from bone marrow of different patients (acute myelogenous leukemia, AML, n=15; acute lymphoblastic leukemia, ALL, n=12; myelodysplastic syndrome, MDS, n=7; choronic myeloid leukemia, CML, n=20; non-Hodgkin lymphoma, NHL, n=21; Hodgkin disease, HD, n=5 ) and compared them with MSCs derived from normal adult bone marrow (n=8) . The growth curve, immunophenotype and in vitro differentiation capacity were investigated. Adipocyte, osteocyte and neural differentiation were detected by Von Kossa stain, Oil-red O staining, RT-PCR and western blotting. Moreover, the chromosomes of different MSCs were detected. At last, hematopoiesis support in vitro was detected by the methylcellulose progenitor assay. Results MSCs derived from ALL, CML, NHL, HD and MDS have similar characteristics in cell morphology and phenotype. They were showed a typital fibrablast like morphology. Under suitable conditions, MSCs have the similar ability of differentiatation into adipocyte, osteoblast and neural cells in vitro. Moreover, all this MSCs had show normal karyotype. At last, MSCs derived from ALL, CML, NHL and HD could express hematopoietic cytokines and possessed hematopoietic supportive ability. But, MSCs derived from AML and MDS showed impaired hematopoiesis support ability, and MSCs isolated from AML showed limited proliferation and impaired differentiation ability. Conclusion There is a population of cells with characteristics of mesenchymal stem cells in hematopoietic disorder patients' bone marrow. But, MSCs derived from AML display pathological changes in proliferation, differentiation and support hematopoiesis, and MSCs derived from MDS display impaired hematopoiesis support ability.Part Two: The Damage Effect of Chemotherapy Agents on Bone Marrow Derived Mesenchymal Stem Cells.Objects: To investigate the changes of human mesenchymal stem cells (MSCs) after exposure to chemotherapeutic agents. Methods: MSCs were isolated from normal adult bone marrow and cultured in medium with different chemotherapy agents. After exposure to chemotherapeutic agents, the change of MSCs' proliferation were investigated, and the differentiation of MSCs was detected by Von Kossa stain. Oil-red O staining and RT-PCR. Moreover, hematopoiesis support in vitro and the expression of hematopoietic cytokines were detected by the methylcellulose progenitor assay and RT-PCR. Results: MSCs were resistant to three agents: MTX, CTX and Bu, and other agents (VCR, VP-16, DXM, Ara-c and DNR) could induce apoptosis of MSCs and reduced the MSCs number. However, MSCs showed recovery after withdrawal of the agents of VCR and DXM. MSCs, after exposure to chemotherapy agents, still have the ability of differentiatation into adipocyte and osteoblast. Moreover, chemotherapy agent treated MSCs could express hematopoietic cytokines and possessed hematopoietic supportive ability. But, after exposure to VCR,DNR, VP-16 and Ara-c, MSCs showed limited proliferation capacity and impaired haematopoiesis support ability. Conclusions: chemotherapy agents commenly used in clinical (VCR, VP-16, Ara-c and DNR) could affect the proliferation and hematopoiesis support abilities of MSCs, but, they did not affect the differentiations and expression of hematopoietic cytokines of MSCs. Moreover, several agents have no affection on MSCs, such as CTX, MTX and Bu.