Self-renewal is a prerequisite for the maintenance of hematopoietic stem cells (HSCs) in the bone marrow throughout adult life. Cytokines are mainly providing pro-survival signals of HSC, whereas low oxygen levels (hypoxia) were recently shown to influence self-renewal. In contrast, the effects on other progenitor cell types is not clear. In the present work, we have analyzed whether hypoxia has any effects on mouse multipotent progenitors. When bone marrow-derived Lin-Sca1+c-kit+ (LSK) cells were kept in hypoxic cultures (1% O2 ) for 4 days together with cytokines, the numbers of colony forming high-proliferative progenitors (HPP-CFC) and precursors for cobble-stone forming cells (CAFC) were increased compared to normoxic conditions. A similar effect was seen with pre-CFCmulti from unfractionated bone marrow, whereas more committed progenitors (CFU-GM) were expanded better in normoxia compared to hypoxia. The observed increase in numbers of primitive colony-forming progenitor cells was associated with maintenance of the c-kit/Sca-1 phenotype and a preferential expansion of immature blast-like appearing cells. The results suggest that a major function of hypoxia is to regulate differentiation by increased self-renewal. Furthermore, in cultures of limited cytokine supply, survival of the stem cell-like cell line FDCP-mix was increased during hypoxia. Thus, hypoxia allows for better survival and self-renewal of multipotent progenitors and HSCs from adult bone marrow. Such culture conditions may have beneficial clinical implications for ex vivo purposes and may improve the yields of stem cells and early progenitors.Original Publication: Pernilla Eliasson, Richard Karlsson and Jan-Ingvar Jönsson, Hypoxia Expands Primitive Hematopoietic Progenitor Cellsfrom Mouse Bone Marrow During In Vitro Culture and Preserves the Colony-Forming Ability, 2006, Journal of Stem Cells, (1), 4, 247-257. https://www.novapublishers.com/catalog/editorial.php?products_id=3730 Copyright: Nova Science Publishers https://www.novapublishers.com/</p