Sub-anesthetic Xenon Increases Erythropoietin Levels in Humans: A Randomized Controlled Trial.

Abstract

The licensed anesthetic xenon, which exerts organ protective properties, was recently added by the World Anti-Doping Agency to the list of prohibited substances. Xenon is supposed to trigger the production of hypoxia-inducible factor 1α (HIF-1α) and subsequently erythropoietin, but data are limited to in vivo experimental work. Therefore we evaluated the effect of xenon on erythropoietin levels in healthy persons. Twenty-four healthy volunteers were randomly assigned either to a group spontaneously breathing xenon 30% (Xe/O2 30%/60%) or a group breathing control gas (N2/O2 40%/60%) for 45min. Primary outcome parameters were erythropoietin levels at several time-points after exposure. Secondary outcome parameters were serum levels of testosterone, cytokines, and growth factors as well as concentrations of xenon in blood and exhalation samples measured at several time-points after exposure. In addition, hemodynamic safety parameters were monitored during exposure. The administration of xenon significantly increased erythropoietin levels 8h after exposure (1.34 [±0.368]; p=0.008), peaking at 24h compared to the baseline values (1.45 [±0.498]; p=0.01) and remained traceable in blood and exhalation probes until 24h after exposure. In contrast, no significant change was observed in the control group. Measurement of stromal cell-derived factor 1 (SDF-1) revealed a significant increase of SDF-1 levels (p=0.005), whereas no differences were observed with respect to growth factors, cytokines, or androgens. In an in vitro chemotaxis assay, endothelial progenitor cells (EPCs) showed a trend towards increased migration in serum samples received from participants after xenon exposure (p=0.080). The present study presents first evidence about a xenon-induced effect on increased erythropoietin levels in healthy volunteers. The study was registered at the European Medicines Agency (EudraCT-number: 2014-000973-38) and at ClinicalTrials.gov (NCT number: 02129400).