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RhEPO improves time to exhaustion by non-hematopoietic factors in humans


Annaheim, Simon; Jacob, Matthias; Krafft, Alexander; Breymann, Christian; Rehm, Markus; Boutellier, Urs (2016). RhEPO improves time to exhaustion by non-hematopoietic factors in humans. European Journal of Applied Physiology, 116(3):623-633.

Abstract

PURPOSE Erythropoietin (EPO) controls red cell volume (RCV) and plasma volume (PV). Therefore, injecting recombinant human EPO (rhEPO) increases RCV and most likely reduces PV. RhEPO-induced endurance improvements are explained by an increase in blood oxygen (O2) transport capacity, which increases maximum O2 uptake ([Formula: see text]O2max). However, it is debatable whether increased RCV or [Formula: see text]O2max are the main reasons for the prolongation of the time to exhaustion (t lim) at submaximal intensity. We hypothesized that high rhEPO doses in particular contracts PV such that the improvement in t lim is not as strong as at lower doses while [Formula: see text]O2max increases in a dose-dependent manner. METHODS We investigated the effects of different doses of rhEPO given during 4 weeks [placebo (P), low (L), medium (M), and high (H) dosage] on RCV, PV, [Formula: see text]O2max and t lim in 40 subjects. RESULTS While RCV increased in a dose-dependent manner, PV decreased independent of the rhEPO dose. The improvements in t lim (P +21.4 ± 23.8 %; L +16.7 ± 29.8 %; M +44.8 ± 62.7 %; H +69.7 ± 73.4 %) depended on the applied doses (R (2) = 0.89) and clearly exceeded the dose-independent [Formula: see text]O2max increases (P -1.7 ± 3.2 %; L +2.6 ± 6.8 %; M +5.7 ± 5.1 %; H +5.6 ± 4.3 %) after 4 weeks of rhEPO administration. Furthermore, the absolute t lim was not related (R (2) ≈ 0) to RCV or to [Formula: see text]O2max. CONCLUSIONS We conclude that a contraction in PV does not negatively affect t lim and that rhEPO improves t lim by additional, non-hematopoietic factors.

Abstract

PURPOSE Erythropoietin (EPO) controls red cell volume (RCV) and plasma volume (PV). Therefore, injecting recombinant human EPO (rhEPO) increases RCV and most likely reduces PV. RhEPO-induced endurance improvements are explained by an increase in blood oxygen (O2) transport capacity, which increases maximum O2 uptake ([Formula: see text]O2max). However, it is debatable whether increased RCV or [Formula: see text]O2max are the main reasons for the prolongation of the time to exhaustion (t lim) at submaximal intensity. We hypothesized that high rhEPO doses in particular contracts PV such that the improvement in t lim is not as strong as at lower doses while [Formula: see text]O2max increases in a dose-dependent manner. METHODS We investigated the effects of different doses of rhEPO given during 4 weeks [placebo (P), low (L), medium (M), and high (H) dosage] on RCV, PV, [Formula: see text]O2max and t lim in 40 subjects. RESULTS While RCV increased in a dose-dependent manner, PV decreased independent of the rhEPO dose. The improvements in t lim (P +21.4 ± 23.8 %; L +16.7 ± 29.8 %; M +44.8 ± 62.7 %; H +69.7 ± 73.4 %) depended on the applied doses (R (2) = 0.89) and clearly exceeded the dose-independent [Formula: see text]O2max increases (P -1.7 ± 3.2 %; L +2.6 ± 6.8 %; M +5.7 ± 5.1 %; H +5.6 ± 4.3 %) after 4 weeks of rhEPO administration. Furthermore, the absolute t lim was not related (R (2) ≈ 0) to RCV or to [Formula: see text]O2max. CONCLUSIONS We conclude that a contraction in PV does not negatively affect t lim and that rhEPO improves t lim by additional, non-hematopoietic factors.

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Additional indexing

Item Type:Journal Article, refereed, original work
Communities & Collections:04 Faculty of Medicine > University Hospital Zurich > Clinic for Obstetrics
Dewey Decimal Classification:610 Medicine & health
Language:English
Date:March 2016
Deposited On:14 Jun 2016 12:49
Last Modified:08 Dec 2017 19:40
Publisher:Springer
ISSN:1439-6319
Publisher DOI:https://doi.org/10.1007/s00421-015-3322-6
PubMed ID:26729211

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