title: Combination of low O(2)  concentration and mesenchymal stromal cells during culture of cord blood CD34(+)  cells improves the maintenance and proliferative capacity of hematopoietic stem cells.
abstract: The physiological approach suggests that an environment associating the mesenchymal stromal cells (MSC) and low O(2) concentration would be most favorable for the maintenance of hematopoietic stem cells (HSCs) in course of ex vivo expansion of hematopoietic grafts. To test this hypothesis, we performed a co-culture of cord blood CD34(+) cells with or without MSC in presence of cytokines for 10 days at 20%, 5%, and 1.5% O(2) and assessed the impact on total cells, CD34(+) cells, committed progenitors (colony-forming cells-CFC) and stem cells activity (pre-CFC and Scid repopulating cells-SRC). Not surprisingly, the expansion of total cells, CD34(+) cells, and CFC was higher in co-culture and at 20% O(2) compared to simple culture and low O(2) concentrations, respectively. However, co-culture at low O(2) concentrations provided CD34(+) cell and CFC amplification similar to classical culture at 20% O(2) . Interestingly, low O(2) concentrations ensured a better pre-CFC and SRC preservation/expansion in co-culture. Indeed, SRC activity in co-culture at 1.5% O(2) was higher than in freshly isolated CD34(+) cells. Interleukin-6 production by MSC at physiologically low O(2) concentrations might be one of the factors mediating this effect. Our data demonstrate that association of co-culture and low O(2) concentration not only induces sufficient expansion of committed progenitors (with respect to the classical culture), but also ensures a better maintenance/expansion of hematopoietic stem cells (HSCs), pointing to the oxygenation as a physiological regulatory factor but also as a cell engineering tool.
authors.affiliation: Aquitaine-Limousin Branch of French Blood Institute (Etablissement Français du Sang, Aquitaine-Limousin, EFS-AL), Bordeaux, France.
authors.forename: Mohammad
authors.initials: M
authors.lastname: Hammoud
authors.forename: Marija
authors.initials: M
authors.lastname: Vlaski
authors.forename: Pascale
authors.initials: P
authors.lastname: Duchez
authors.forename: Jean
authors.initials: J
authors.lastname: Chevaleyre
authors.forename: Xavier
authors.initials: X
authors.lastname: Lafarge
authors.forename: Jean-Michel
authors.initials: JM
authors.lastname: Boiron
authors.forename: Vincent
authors.initials: V
authors.lastname: Praloran
authors.forename: Philippe
authors.initials: P
authors.lastname: Brunet De La Grange
authors.forename: Zoran
authors.initials: Z
authors.lastname: Ivanovic
mesh_terms: D000444:Aldehyde Dehydrogenase / Q000378:metabolism; D018952:Antigens, CD34 / Q000378:metabolism; D015415:Biomarkers / Q000378:metabolism; D002450:Cell Communication; D018929:Cell Culture Techniques; D002454:Cell Differentiation; D049109:Cell Proliferation; D002478:Cells, Cultured; D018920:Coculture Techniques; D005312:Fetal Blood / Q000166:cytology*; D006412:Hematopoietic Stem Cells / Q000276:immunology / Q000378:metabolism*; D006801:Humans; D015850:Interleukin-6 / Q000378:metabolism; D059630:Mesenchymal Stem Cells / Q000276:immunology / Q000378:metabolism*; D010100:Oxygen / Q000378:metabolism*; D013997:Time Factors
chemical_list: D018952:Antigens, CD34; D015415:Biomarkers; C508600:IL6 protein, human; D015850:Interleukin-6; D000444:Aldehyde Dehydrogenase; D010100:Oxygen