title: Neopterin, inflammation-associated product, prolongs erythropoiesis suppression in aged SAMP1 mice due to senescent stromal-cell impairment.
abstract: Anemia induced by inflammation is well known to be more serious in the elderly than in non-elderly adults; however, the reason why this is so remains unclear. Neopterin produced by monocytes during inflammation promotes myelopoiesis but suppresses B-lymphopoiesis and erythropoiesis, by activating stromal cells in mice. Here, age-related changes in the erythropoietic response to neopterin were determined using senescence accelerated mice (SAMP1) with senescence stromal-cell impairment. Intravenous injection of neopterin into young mice (8-12 weeks old) resulted in a decrease in erythroid progenitor cell number in the bone marrow (BM), concomitant with an increase in myeloid progenitor cell number over one week. Intravenous injection of neopterin into aged mice (30-36 weeks old) resulted in a prolonged decrease in erythroid progenitor cell number in the BM over three weeks and a limited increase in myeloid progenitor cell number over one day. Neopterin treatment induced a decrease in serum erythropoietin concentrations in young mice but not in aged mice. The gene expression of tumor necrosis factor α (TNF-α), a negative regulator of erythropoiesis, was up-regulated in the BM of both young and aged mice, and the degree of TNF-α up-regulation was the same in both groups. The gene expression of interleukin (IL)-11, a positive regulator of erythropoiesis, was also up-regulated over one day in both young and aged mice. However, IL-11 gene expression remained up-regulated thereafter in young mice, whereas it was rapidly down-regulated in aged mice. These data suggest that prolonged suppression of erythropoiesis in aged mice may be due to a decrease in the production of positive regulators rather than to an increase in the production of negative regulators. Our combined data suggest that age-related impairment of stromal cells induces serious anemia in the elderly during inflammation.
authors.affiliation: Department of Functional Morphology, Nihon University School of Medicine, Tokyo 173-8610, Japan.
authors.forename: Kazuo
authors.initials: K
authors.lastname: Aisaki
authors.forename: Isao
authors.initials: I
authors.lastname: Tsuboi
authors.forename: Tomonori
authors.initials: T
authors.lastname: Harada
authors.forename: Hideki
authors.initials: H
authors.lastname: Oshima
authors.forename: Akiko
authors.initials: A
authors.lastname: Yamashita
authors.forename: Yoko
authors.initials: Y
authors.lastname: Hirabayashi
authors.forename: Jun
authors.initials: J
authors.lastname: Kanno
authors.forename: Tohru
authors.initials: T
authors.lastname: Inoue
authors.forename: Shin
authors.initials: S
authors.lastname: Aizawa
mesh_terms: D000375:Aging / Q000502:physiology*; D000740:Anemia / Q000378:metabolism / Q000503:physiopathology; D000818:Animals; D001853:Bone Marrow / Q000378:metabolism / Q000473:pathology; D001854:Bone Marrow Cells / Q000378:metabolism* / Q000473:pathology; D016207:Cytokines / Q000096:biosynthesis; D015672:Erythroid Precursor Cells / Q000378:metabolism; D004920:Erythropoiesis / Q000502:physiology*; D020869:Gene Expression Profiling; D007249:Inflammation / Q000378:metabolism / Q000503:physiopathology; D008297:Male; D051379:Mice; D008817:Mice, Mutant Strains; D038042:Myelopoiesis / Q000502:physiology; D019798:Neopterin / Q000378:metabolism* / Q000494:pharmacology; D060888:Real-Time Polymerase Chain Reaction; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017154:Stromal Cells / Q000378:metabolism* / Q000473:pathology
chemical_list: D016207:Cytokines; D019798:Neopterin