The blood transcriptional signature of recombinant human erythropoietin administration and implications for anti-doping strategies

Background: Recombinant human erythropoietin (rHuEPO) is frequently abused by athletes as a performance-enhancing drug, despite being prohibited by the World Anti-Doping Agency. Although the methods to detect blood doping, including rHuEPO injections, have improved in recent years, they remain imperfect. Methods: In a proof-of-principle study, we identified, replicated and validated the whole-blood transcriptional signature of rHuEPO in endurance-trained Caucasian males at sea-level (n = 18) and Kenyan endurance runners at moderate altitude (n = 20), all of whom received rHuEPO injections for four weeks. Results: Transcriptional profiling shows that hundreds of transcripts were altered by rHuEPO in both cohorts. The main regulated expression pattern, observed in all participants, was characterised by a “rebound” effect with a profound up-regulation during rHuEPO and a subsequent down-regulation up to four weeks post administration. The functions of the identified genes were mainly related to the functional and structural properties of the red blood cell. Of the genes identified to be differentially expressed during and post rHuEPO, we further confirmed a whole blood 34-transcript signature that can distinguish between samples collected pre, during and post rHuEPO administration. Conclusion: By providing biomarkers that can reveal rHuEPO use, our findings represent an advance in the development of new methods for the detection of blood doping.