Discovery of c.577del in EPO: Investigations into endogenous EPO double-band detected in blood with SAR-PAGE

Recently, some athletes were repetitively found to have rEPO positive results, including a characterized double-band pattern in blood samples, in routine doping analysis. In contrast to previous findings from excretion studies, this double-band pattern showed the same relative intensity even when the samples were collected weeks (/months) apart. We therefore suspected that these "positive" doping control samples were related with a novel pathway of endogenous EPO production. Thus, follow-up investigations were warranted to characterize the origin of such analytical test results and to avoid the issuing of adverse analytical findings in the absence of rEPO by identifying the root cause of these "constantly positives." In this study, we designed and conducted a series of causal studies, including population screening of EPO profiles, exploration of EPO de-N-glycosylation, single nucleotide polymorphism (SNP) browsing in EPO, sequencing of EPO exons, genealogical analysis of the c.577del EPO variant, and finally expression and investigation of mutant EPO. In summary, we found that these "constantly positives" were related to endogenous EPO production associated with the c.577del EPO variant. The frequency of this variant was 0.39% in our Chinese population pool. The mutant EPO encoded by this variant is 27 amino acids longer than the wild-type. The molecular weight of this mutant EPO is approximately the same as that of rEPO, exhibiting a similar electrophoretic behavior. To prevent charges against carriers of the c.577del variant, a revised rEPO testing strategy has been implemented in the new version of TD EPO.

Olympic anti-doping laboratory: the analytical technological road from 2016 Rio De Janeiro to 2021 Tokyo

The summer Olympic Games is the major mega sports event since the first modern era Olympiad, held in Athens, Greece in 1896. International Olympic Committee (IOC) has the responsibility of the organization of the summer and winter Games ensuring the broadcast in all corners of earth. The World Anti-Doping Agency (WADA) is the responsible organization of the fight against doping in sports. IOC and WADA support the event's country WADA Accredited Laboratory to incorporate the maximum of the new analytical technologies to become applicable during the event's antidoping testing. The current study reviewed the last 5 years progresses of the antidoping system with emphasis on the laboratory field.

Annual banned-substance review: Analytical approaches in human sports drug testing 2019/2020

Analytical chemistry-based research in sports drug testing has been a dynamic endeavor for several decades, with technology-driven innovations continuously contributing to significant improvements in various regards including analytical sensitivity, comprehensiveness of target analytes, differentiation of natural/endogenous substances from structurally identical but synthetically derived compounds, assessment of alternative matrices for doping control purposes, and so forth. The resulting breadth of tools being investigated and developed by anti-doping researchers has allowed to substantially improve anti-doping programs and data interpretation in general. Additionally, these outcomes have been an extremely valuable pledge for routine doping controls during the unprecedented global health crisis that severely affected established sports drug testing strategies. In this edition of the annual banned-substance review, literature on recent developments in anti-doping published between October 2019 and September 2020 is summarized and discussed, particularly focusing on human doping controls and potential applications of new testing strategies to substances and methods of doping specified the World Anti-Doping Agency's 2020 Prohibited List.

Horseradish-peroxidase-conjugated anti-erythropoietin antibodies for direct recombinant human erythropoietin detection: Proof of concept

Antidoping testing for recombinant human erythropoietin (EPO) is routinely performed by gel electrophoresis followed by western blot analysis with primary and secondary antibodies. The two antibody steps add more than 24 h to the testing time of a purified sample. The aim of this study was to test the concept of using directly horseradish-peroxidase (HRP)-conjugated anti-EPO primary antibody, without the need for a secondary antibody, to reduce the analysis time and eliminate non-specific cross-reactivity with secondary antibodies. An in-house, periodate coupling (R&D systems, clone AE7A5) and three commercially available anti-human EPO-HRP conjugates from Genetex, Novus Biologicals and Santa Cruz were evaluated for specificity and sensitivity, using recombinant human EPO standards, negative human urine samples and urine samples from an EPO excretion study. The in-house anti-EPO-HRP conjugate was performed as well as the current two-step application of unconjugated primary and secondary antibodies used in routine analysis, with comparable specificity and sensitivity. The analysis time was markedly reduced for purified samples from 25 h with the routine method down to 7 h with the in-house HRP conjugate. Of the three commercially available conjugates tested, only the Santa Cruz anti-EPO-HRP conjugate showed comparable specificity but had lower sensitivity to both the in-house and the antibody combination currently applied routinely. The other two commercially available conjugates (Genetex and Novus Biologicals) did not show any visible bands with the EPO standards. The results clearly demonstrate the potential utility of a directly HRP-conjugated anti-EPO antibody to reduce analysis time for EPO in doping control.