Elevation of iron storage in humans attenuates the pulmonary vascular response to hypoxia

Nicole K Bart, M Kate Curtis, Hung-Yuan Cheng, Sara L Hungerford, Ross McLaren, Nayia Petousi, Keith L Dorrington, Peter A Robbins

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Abstract

Sustained hypoxia over several hours induces a progressive rise in pulmonary artery systolic pressure (PASP). Administration of intravenous iron immediately prior to the hypoxia exposure abrogates this effect, suggesting that manipulation of iron stores may modify hypoxia-induced pulmonary hypertension. Iron (ferric carboxymaltose) administered intravenously has a plasma half-life of 7-12 h. Thus any therapeutic use of intravenous iron would require its effect on PASP to persist long after the iron-sugar complex has been cleared from the blood. To examine this, we studied PASP during sustained (6 h) hypoxia on 4 separate days (days 0, 1, 8, and 43) in 22 participants. On day 0, the rise in PASP with hypoxia was well matched between the iron and saline groups. On day 1, each participant received either 1 g of ferric carboxymaltose or saline in a double-blind manner. After administration of intravenous iron, the rise in PASP with hypoxia was attenuated by ∼50%, and this response remained suppressed on both days 8 and 43 (P < 0.001). Following administration of intravenous iron, values for ferritin concentration, transferrin saturation, and hepcidin concentration rose significantly (P < 0.001, P < 0.005, and P < 0.001, respectively), and values for transferrin concentration fell significantly (P < 0.001). These changes remained significant at day 43 We conclude that the attenuation of the pulmonary vascular response to hypoxia by elevation of iron stores persists long after the artificial iron-sugar complex has been eliminated from the blood. The persistence of this effect suggests that intravenous iron may be of benefit in some forms of pulmonary hypertension.

Original languageEnglish
Pages (from-to)537-544
Number of pages8
JournalJournal of Applied Physiology
Volume121
Issue number2
Early online date14 Jul 2016
DOIs
Publication statusPublished - 1 Aug 2016

Keywords

  • hypoxia inducible factor
  • pulmonary hypertension
  • pulmonary circulation

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  • Cite this

    Bart, N. K., Curtis, M. K., Cheng, H-Y., Hungerford, S. L., McLaren, R., Petousi, N., Dorrington, K. L., & Robbins, P. A. (2016). Elevation of iron storage in humans attenuates the pulmonary vascular response to hypoxia. Journal of Applied Physiology, 121(2), 537-544. https://doi.org/10.1152/japplphysiol.00032.2016