Administration of recombinant human erythropoietin (rHuEpo) improves endurance performance. Hence rHuEpo is, allegedly, frequently subject to abuse by athletes, although rHuEpo is prohibited by the World Anti-Doping Agency. A transcriptomic-based longitudinal screening approach has the potential to improve further the performance of current detection methods. AIM: To assess the effects of rHuEpo on blood gene expression profiles in order to identify a “molecular signature” of rHuEpo doping. METHODS: 19 Caucasian trained males at sea-level (Scotland – SCO) and 20 Kenyan endurance runners at moderate altitude (~2,150 m, Kenya – KEN) received rHuEpo injections of 50 IU∙kg-1 body mass every two days for 4 weeks. Blood was obtained 2 weeks before, during and 4 weeks after administration. 3,000 m time trial performance was measured pre, post administration and at the end of the study. RNA was extracted from blood stabilized in Tempus RNA tubes, amplified, labelled and hybridized to Illumina HumanHT-12v4 Expression BeadChips. Expression data was analyzed using Rank Products with a 5% false discovery rate and an additional 1.5 fold-change threshold. A subset of target and housekeeping genes was further validated using QuantiGene Plex assay. RESULTS: Despite markedly different baseline values between SCO and KEN, as exemplified by the haematocrit (41.9 ± 1.8% vs. 45.3 ± 2.6, p < 0.001), key blood parameters significantly increased during rHuEpo in both groups (p < 0.001) to reach similar levels at the end of administration (49.2 ± 2.0% vs. 49.6 ± 2.6, p = 0.638). The relative improvements in running performance post rHuEpo (~5%) and 4 weeks post administration (~3%) compared to baseline were of similar magnitude in both groups (p > 0.188). These results confirmed that the perturbation involving rHuEpo worked effectively. Relative to baseline, the expression of hundreds of genes were found to be altered by rHuEpo. In particular, 30 transcripts were already differentially expressed two days after the first injection while 15 transcripts were profoundly up-regulated during and subsequently down-regulated up to 4 weeks post administration in both groups. Importantly, the same pattern was observed in all subjects. The functions of the discovered genes were mainly related to either the functional or structural properties of the erythrocyte or to the cell cycle and its regulation. CONCLUSION: This research successfully identified the blood “molecular signature” of rHuEpo administration and provides the strongest evidence to date that gene biomarkers have the potential to substantially improve the performance of current anti-doping methods such as the Athlete Biological Passport for rHuEpo detection.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:591990 |
| Date | January 2014 |
| Creators | Durussel, Jérôme |
| Publisher | University of Glasgow |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://theses.gla.ac.uk/4962/ |
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