title: Inhibition of hematopoiesis in normal human long-term marrow cultures treated with recombinant human macrophage colony-stimulating factor.
abstract: The effects of recombinant human macrophage colony-stimulating factor (rhCSF-1) in long-term marrow cultures (LTMC) established from normal bone marrow cells were examined. When added during the first 3 weeks of culture (every second day, at 15 ng/mL), rhCSF-1 strongly inhibited the growth of all hematopoietic progenitors analyzed (colony-forming unit-MIX [CFU-MIX], CFU-granulocyte macrophage [CFU-GM], CFU-M, CFU-G, burst-forming unit-erythroid). Paralleling the inhibition of progenitors was the complete loss of adipocytes from the stromal layer of rhCSF-1-treated cultures. The inhibitory effect of rhCSF-1 correlated in all instances with the accumulation in the supernatants of these cultures of an activity (different from CSF-1) that inhibited colony formation in semisolid cultures. When addition of rhCSF-1 was delayed 3 weeks, its inhibitory effects were significantly reduced, which correlated with reduced inhibitory activity detected in the supernatants. Analysis of CSF-1 concentration by radioreceptor assay confirmed that added rhCSF-1 increased culture CSF-1 levels and showed that the decreased inhibition observed when rhCSF-1 is added later in culture was not due to decreased CSF-1 levels at that point. In contrast, the ability of rhCSF-1 to inhibit hematopoiesis and accumulate inhibitory activity in LTMC correlated with its rate of utilization, much higher in the first 2 weeks of culture, when the stromal layer was being established, than later. These observations document the inhibitory effect of rhCSF-1 on all aspects of hematopoiesis conducted in cultures that simulate the hematopoietic microenvironment, demonstrate the importance of accessory/stromal cells in mediating the effects of rhCSF-1 in LTMC, and point to an inhibitory activity as the mediating agent.
authors.affiliation: Department of Medicine, University of Alberta, Edmonton, Canada.
authors.forename: H
authors.initials: H
authors.lastname: Mayani
authors.forename: L J
authors.initials: LJ
authors.lastname: Guilbert
authors.forename: S C
authors.initials: SC
authors.lastname: Clark
authors.forename: A
authors.initials: A
authors.lastname: Janowska-Wieczorek
mesh_terms: D001853:Bone Marrow / Q000187:drug effects / Q000502:physiology*; D001854:Bone Marrow Cells; D002448:Cell Adhesion; D002478:Cells, Cultured; D003114:Colony-Forming Units Assay; D006410:Hematopoiesis / Q000187:drug effects*; D006412:Hematopoietic Stem Cells / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D006801:Humans; D016173:Macrophage Colony-Stimulating Factor / Q000494:pharmacology*; D011994:Recombinant Proteins / Q000494:pharmacology
chemical_list: D011994:Recombinant Proteins; D016173:Macrophage Colony-Stimulating Factor