title: Individual and combined effects of mesenchymal stromal cells and recombinant stimulatory cytokines on the in vitro growth of primitive hematopoietic cells from human umbilical cord blood.
abstract: OBJECTIVE
  We have previously characterized the in vitro growth of two cord blood-derived hematopoietic cell populations in liquid cultures supplemented with recombinant cytokines. In the present study, we assessed the effects of bone marrow-derived mesenchymal stromal cells (MSC) on the growth of such cells.
  
  
  METHODS
  CD34(+) CD38(+) Lin(-) and CD34(+) CD38(-) Lin(-) cells were obtained by negative selection, and cultured in the presence of marrow-derived MSC and/or early- and late-acting cytokines. Hematopoietic cell growth was assessed throughout a 30-day culture period.
  
  
  RESULTS
  In the presence of MSC alone, both populations showed significant proliferation. Direct contact between MSC and CD34(+) cells was fundamental for optimal growth, especially for CD34(+) CD38(-) Lin(-) cells. In the presence of early-acting cytokines alone, cell growth was significantly higher than in cultures established with MSC but no cytokines. In cultures containing both MSC and early-acting cytokines, a further stimulation was observed only for CD34(+) CD38(-) Lin(-) cells. The cytokine cocktail containing both early- and late-acting cytokines was significantly more potent at inducing hematopoietic cell growth than the early-acting cytokine cocktail. When cultures were supplemented with early- and late-acting cytokines, MSC had no further effect on the growth of hematopoietic cells.
  
  
  CONCLUSIONS
  MSC seem to play a key role, particularly on more primitive (CD34(+) CD38(-) Lin(-)) cells, only in the absence of cytokines or the presence of early-acting cytokines. When both early- and late-acting cytokines are present in culture, MSC seem to be unnecessary for optimal development of CFC and CD34(+) cells.
authors.affiliation: Hematopoietic Stem Cells Laboratory, Oncology Research Unit, Oncology Hospital, National Medical Center, IMSS, Mexico City, Mexico.
authors.forename: Patricia
authors.initials: P
authors.lastname: Flores-Guzmán
authors.forename: Eugenia
authors.initials: E
authors.lastname: Flores-Figueroa
authors.forename: Juan J
authors.initials: JJ
authors.lastname: Montesinos
authors.forename: Guadalupe
authors.initials: G
authors.lastname: Martínez-Jaramillo
authors.forename: Veronica
authors.initials: V
authors.lastname: Fernández-Sánchez
authors.forename: Ignacio
authors.initials: I
authors.lastname: Valencia-Plata
authors.forename: Guadalupe
authors.initials: G
authors.lastname: Alarcón-Santos
authors.forename: Hector
authors.initials: H
authors.lastname: Mayani
mesh_terms: D051997:ADP-ribosyl Cyclase 1 / Q000096:biosynthesis; D018952:Antigens, CD34 / Q000096:biosynthesis; D001854:Bone Marrow Cells / Q000166:cytology / Q000378:metabolism*; D048708:Cell Growth Processes; D018920:Coculture Techniques; D016207:Cytokines / Q000494:pharmacology*; D005312:Fetal Blood / Q000166:cytology; D006412:Hematopoietic Stem Cells / Q000166:cytology / Q000378:metabolism*; D006801:Humans; D007114:Immunization; D059630:Mesenchymal Stem Cells / Q000166:cytology / Q000378:metabolism*; D011994:Recombinant Proteins / Q000494:pharmacology*; D017154:Stromal Cells / Q000166:cytology
chemical_list: D018952:Antigens, CD34; D016207:Cytokines; D011994:Recombinant Proteins; D051997:ADP-ribosyl Cyclase 1