IEF pattern classification-derived criteria for the identification of epoetin-δ in urine

Hepcidin as a potential biomarker for blood doping

The concentration of hepcidin, a key regulator of iron metabolism, is suppressed during periods of increased erythropoietic activity. The present study obtained blood samples from 109 elite athletes and examined the correlations between hepcidin and markers of erythropoiesis and iron metabolism (i.e., haemoglobin, erythropoietin (EPO), ferritin, erythroferrone (ERFE), and iron concentration). Furthermore, an administration study was undertaken to examine the effect of recombinant human EPO (rhEPO) delta (Dynepo™) on hepcidin concentrations in healthy male volunteers. The effects on hepcidin were then compared with those on reticulocyte percentage (Ret%) and ferritin concentration. There was a significant positive correlation between hepcidin and ferritin, iron, and haemoglobin levels in athletes, whereas hepcidin showed an inverse correlation with ERFE. Administration of rhEPO delta reduced hepcidin levels, suggesting that monitoring hepcidin may increase the sensitivity of the Athlete Biological Passport (ABP) for detecting rhEPO abuse. Copyright © 2016 John Wiley & Sons, Ltd.

Detection of erythropoiesis-stimulating agents in human anti-doping control: past, present and future

Stimulation of erythropoiesis is one of the most efficient ways of doping. This type of doping is advantageous for aerobic physical exercise and of particular interest to endurance athletes. Erythropoiesis, which takes place in bone marrow, is under the control of EPO, a hormone secreted primarily by the kidneys when the arterial oxygen tension decreases. In certain pathological disorders, such as chronic renal failure, the production of EPO is insufficient and results in anemia. The pharmaceutical industry has, thus, been very interested in developing drugs that stimulate erythropoiesis. With this aim, various strategies have been, and continue to be, envisaged, giving rise to an expanding range of drugs that are good candidates for doping. Anti-doping control has had to deal with this situation by developing appropriate methods for their detection. This article presents an overview of both the drugs and the corresponding methods of detection, and thus follows a roughly chronological order.

Involvement of the health industry in the fight against doping in sport

Most substances used for doping in sport are legitimate pharmaceutical products deviated from their intended therapeutic applications. One of the major challenges for anti-doping authorities, in anticipation of future doping trends, is to assess the doping potential of drugs in development by the health industry and to timely develop anti-doping analytical methods to detect their abuse before such drugs become available to athletes intending to use them as doping agents. In this regard, the World Anti-Doping Agency (WADA) has recently consolidated several agreements with representatives from the pharmaceutical sector in order to establish a framework of collaboration and to facilitate the identification and transfer of information on drugs in development. The context of the collaborative effort between WADA and the pharmaceutical and biotechnology industries, as well as the role of drug regulatory agencies in an integrated process in support of the fight against doping in sport are described in this article.

Recent developments in doping testing for erythropoietin

The constant development of new erythropoiesis-stimulating agents (ESAs), since the first introduction of recombinant erythropoietin (rhEpo) for clinical use, has also necessitated constant development of methods for detecting the abuse of these substances. Doping with ESAs is prohibited according to the World Anti-Doping Code and its prohibited list of substances and methods. Since the first publication of a direct and urine-based detection method in 2000, which uses changes in the Epo isoform profile as detected by isoelectric focusing in polyacrylamide slab gels (IEF-PAGE), the method has been constantly adapted to the appearance of new ESAs (e.g., Dynepo, Mircera). Blood had to be introduced as an additional matrix, because Mircera (a PEGylated Epo) is best confirmed in serum or plasma after immunoaffinity purification. A Mircera ELISA was developed for fast screening of sera. With the appearance of Dynepo and copy epoetins, the additional application of sodium dodecylsulfate polyacrylamide gel electrophoresis (SDS-PAGE or equivalent) became necessary. The haematological module of the Athlete Biological Passport is the latest development in multivariable indirect testing for ESA doping. The article summarizes the main strategies currently used in Epo anti-doping testing with special focus on new developments made between 2009 and 2010.

The athlete biological passport

BACKGROUND

In elite sports, the growing availability of doping substances identical to those naturally produced by the human body seriously limits the ability of drug-testing regimes to ensure fairness and protection of health.

CONTENT

The Athlete Biological Passport (ABP), the new paradigm in testing based on the personalized monitoring of biomarkers of doping, offers the enormous advantage of being independent of this endless pharmaceutical race. Doping triggers physiological changes that provide physiological enhancements. In the same way that disease-related biomarkers are invaluable tools that assist physicians in the diagnosis of pathology, specifically selected biomarkers can be used to detect doping.

SUMMARY

The ABP is a new testing paradigm with immense potential value in the current climate of rapid advancement in biomarker discovery. In addition to its original aim of providing proof of a doping offense, the ABP can also serve as a platform for a Rule of Sport, with the presentation before competition of the ABP to objectively demonstrate that the athlete will participate in a healthy physiological condition that is unaltered by performance-enhancing drugs. Finally, the decision-support system used today for the biological monitoring of world top-level athletes can also be advantageously transferred to other areas of clinical practice to reach the goal of personalized medicine.

Surface plasmon resonance in doping analysis

Doping analysis relies on the determination of prohibited substances that should not be present in the body of an athlete or that should be below a threshold value. In the case of xenobiotics their mere presence is sufficient to establish a doping offence. However, in the case of human biotics the analytical method faces the difficulty of distinguishing between endogenous and exogenous origin. For this purpose ingenious strategies have been implemented, often aided by state-of-the-art technological advancements such as mass spectrometry in all its possible forms. For larger molecules, i.e. protein hormones, the innate structural complexity, the heterogeneous nature, and the extremely low levels in biological fluids have rendered the analytical procedures heavily dependent of immunological approaches. Although approaches these confer specificity and sensitivity to the applications, most rely on the use of two, or even three, antibody incubations with the consequent increment in assay variability. Moreover, the requirement for different antibodies that separately recognise different epitopes in screening and confirmation assays further contributes to differences encountered in either measurement. The development of analytical techniques to measure interactions directly, such as atomic force microscopy, quartz crystal microbalance or surface plasmon resonance, have greatly contributed to the accurate evaluation of molecular interactions in all fields of biology, and expectations are that this will only increase. Here, an overview is provided of surface plasmon resonance, and its particular value in application to the field of doping analysis.