Suppression of erythropoiesis by dietary nitrate.
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Authors
Ashmore, Tom
Fernandez, BO
Evans, Colin
Huang, Yun
Feelisch, M
Publication Date
2015-03-01Journal Title
FASEB J
ISSN
0892-6638
Publisher
The FASEB Journal
Volume
29
Issue
3
Pages
1102-1112
Language
English
Type
Article
This Version
VoR
Metadata
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Ashmore, T., Fernandez, B., Evans, C., Huang, Y., Mendes Branco, C. B., Griffin, J., Johnson, R., et al. (2015). Suppression of erythropoiesis by dietary nitrate.. FASEB J, 29 (3), 1102-1112. https://doi.org/10.1096/fj.14-263004
Abstract
In mammals, hypoxia-triggered erythropoietin release increases red blood cell mass to meet tissue oxygen demands. Using male Wistar rats, we unmask a previously unrecognized regulatory pathway of erythropoiesis involving suppressor control by the NO metabolite and ubiquitous dietary component nitrate. We find that circulating hemoglobin levels are modulated by nitrate at concentrations achievable by dietary intervention under normoxic and hypoxic conditions; a moderate dose of nitrate administered via the drinking water (7 mg NaNO₃/kg body weight/d) lowered hemoglobin concentration and hematocrit after 6 d compared with nonsupplemented/NaCl-supplemented controls. The underlying mechanism is suppression of hepatic erythropoietin expression associated with the downregulation of tissue hypoxia markers, suggesting increased pO₂. At higher nitrate doses, however, a partial reversal of this effect occurred; this was accompanied by increased renal erythropoietin expression and stabilization of hypoxia-inducible factors, likely brought about by the relative anemia. Thus, hepatic and renal hypoxia-sensing pathways act in concert to modulate hemoglobin in response to nitrate, converging at an optimal minimal hemoglobin concentration appropriate to the environmental/physiologic situation. Suppression of hepatic erythropoietin expression by nitrate may thus act to decrease blood viscosity while matching oxygen supply to demand, whereas renal oxygen sensing could act as a brake, averting a potentially detrimental fall in hematocrit.
Keywords
hypoxia, kidney, oxygen sensing, Animals, Anoxia, Dietary Supplements, Epoetin Alfa, Erythropoiesis, Erythropoietin, Hemoglobins, Hypoxia-Inducible Factor 1, alpha Subunit, Immunoenzyme Techniques, Kidney, Liver, Male, Nitrates, Oxygen, Rats, Rats, Wistar, Recombinant Proteins
Sponsorship
This work was supported by British Heart Foundation Studentship FS/09/050 (to T.A.). A.J.M. thanks the Research Councils UK for supporting his academic fellowship and the WYNG Foundation of Hong Kong for support. J.L.G is supported by the European Union Framework 7 Inheritance project, R.S.J. is supported by a Wellcome Trust Principal research fellowship, and M.F. is supported by funds from the Faculty of Medicine, University of Southampton.
Funder references
Biotechnology and Biological Sciences Research Council (BB/H013539/2)
Biotechnology and Biological Sciences Research Council (BB/H013539/1)
Wellcome Trust (092738/Z/10/Z)
Identifiers
External DOI: https://doi.org/10.1096/fj.14-263004
This record's URL: https://www.repository.cam.ac.uk/handle/1810/261430
Rights
Attribution 4.0 International, Attribution 4.0 International, Attribution 4.0 International, Attribution 4.0 International, Attribution 4.0 International
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