Emrich IE, Dederer J, Kircher A, Klemis V, Lennartz CS, Untersteller K, Wagenpfeil S, Fliser D, Wolf M, Heine GH. Does a rise in plasma erythropoietin after high-altitude exposure affect FGF23 in healthy volunteers on a normal or low-phosphorus diet?
Nutr Metab Cardiovasc Dis 2019;
29:1361-1367. [PMID:
31653518 DOI:
10.1016/j.numecd.2019.09.002]
[Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/16/2019] [Revised: 08/11/2019] [Accepted: 09/02/2019] [Indexed: 12/13/2022]
Abstract
BACKGROUND AND AIMS
Data of experimental rodent models suggest that hypoxia with subsequent increase in erythropoietin stimulates the expression of the phosphaturic hormone fibroblast growth factor 23 (FGF23).
METHODS AND RESULTS
To translate the findings of animal studies into human physiology, herein we exposed eight healthy volunteers to high altitude (2656 m above sea level) for four days. The volunteers were randomized on a low-phosphorous diet (n = 4) or a normal phosphorus diet (n = 4). Although high-altitude exposure caused a significant increase in plasma erythropoietin (EPO) (before high-altitude exposure: low phosphorus: median EPO 6.6 mIU/ml [interquartile range (IQR) 6.0; 8.2], normal phosphorus: median EPO 9.0 mIU/ml [IQR 7.9; 11.5]; at day 2: low phosphorus: median EPO 21.3 mIU/ml [IQR 19.5; 23.8], normal phosphorus: median EPO 19.4 mIU/ml [IQR 18.0; 20.8]), there was no consistent increase in plasma c-terminal FGF23 or plasma intact FGF23. We observed only a single, intermittent peak in c-terminal FGF23 levels after 5 h of maximal aerobic exercise.
CONCLUSION
These data do not support a substantial effect of moderate hypoxia alone on the expression of FGF23, but they suggest that combined exercise and high-altitude exposure may temporarily induce FGF23 expression.
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