title: Biological features of mesenchymal stem cells from human bone marrow.
abstract: OBJECTIVE
  To study the biological characteristics of mesenchymal stem cells (MSCs) from human bone marrow.
  
  
  METHODS
  A culture of mesenchymal stem cells was initiated from bone marrow low-density mononuclear cells separated by Percoll Centrifugation and maintained in low-glucose Dulbecco's modified Eagle's medium (DMEM) with 10% selected fetal calf serum. Cell growth pattern and its responses to cytokines were evaluated by trypan blue exclusion and MTT test, respectively. Cell cycle and surface antigenic features were analyzed by flow cytometry technique. Cytochemistry characteristics of MSCs were determined.
  
  
  RESULTS
  Easy-handling methods to isolate and culture expand MSCs were developed in this study. MSCs were unique in their phenotypes. They were positive for CD29, CD44, CD166, and negative for CD34, CD45, HLA-DR and Ulex europaeus. Cytochemistry evaluation showed that MSCs were homogeneously positive for acid alpha-naphthl acetate esterase (ANAE), glycogen (periodic acid Schiff reaction, PAS), and negative for acid phosphatase (ACP) and the Sudan black reaction (SB). Around 5% of them were positive for alkaline phosphatase (ALP). The cells had a population doubling time of 30 hours and cell cycle analysis showed that approximately 10% of them were in S phase. MSCs grew at significantly different rates when incubated in the presence of various recombinant human cytokines, of which interferon gamma, tumor necrosis factor alpha, stem cell factor and insulin-like growth factor promoted the proliferation of MSCs dramatically, while others tested had no effects on cell growth.
  
  
  CONCLUSIONS
  MSCs are a homogenous population of cells that have unique growth, phenotypical and cytochemical characteristics. Furthermore, the diverse responses of MSCs to different cytokines provide a clue for the selection of optimal expansion and maintenance of MSCs.
authors.affiliation: Department of Cell Biology, Institute of Basic Medical Sciences, Beijing 100850, China. guozk89@yahoo.com
authors.forename: Z
authors.initials: Z
authors.lastname: Guo
authors.forename: J
authors.initials: J
authors.lastname: Yang
authors.forename: X
authors.initials: X
authors.lastname: Liu
authors.forename: X
authors.initials: X
authors.lastname: Li
authors.forename: C
authors.initials: C
authors.lastname: Hou
authors.forename: P H
authors.initials: PH
authors.lastname: Tang
authors.forename: N
authors.initials: N
authors.lastname: Mao
mesh_terms: D020410:Activated-Leukocyte Cell Adhesion Molecule / Q000032:analysis; D018952:Antigens, CD34 / Q000032:analysis; D001854:Bone Marrow Cells / Q000737:chemistry / Q000166:cytology* / Q000187:drug effects; D002455:Cell Division / Q000187:drug effects; D016207:Cytokines / Q000494:pharmacology; D006684:HLA-DR Antigens / Q000032:analysis; D006651:Histocytochemistry; D006801:Humans; D018960:Hyaluronan Receptors / Q000032:analysis; D019012:Integrin beta1 / Q000032:analysis; D017493:Leukocyte Common Antigens / Q000032:analysis; D008648:Mesoderm / Q000737:chemistry / Q000166:cytology* / Q000187:drug effects; D013234:Stem Cells / Q000737:chemistry / Q000166:cytology* / Q000187:drug effects
chemical_list: D020410:Activated-Leukocyte Cell Adhesion Molecule; D018952:Antigens, CD34; D016207:Cytokines; D006684:HLA-DR Antigens; D018960:Hyaluronan Receptors; D019012:Integrin beta1; D017493:Leukocyte Common Antigens