Degradation of urine samples and its influence on the 13C/12C ratios of excreted steroids

Current Insights into the Steroidal Module of the Athlete Biological Passport

For decades, the class of anabolic androgenic steroids has represented the most frequently detected doping agents in athletes' urine samples. Roughly 50% of all adverse analytical findings per year can be attributed to anabolic androgenic steroids, of which about 2/3 are synthetic exogenous steroids, where a qualitative analytical approach is sufficient for routine doping controls. For the remaining 1/3 of findings, caused by endogenous steroid-derived analytical test results, a more sophisticated quantitative approach is required, as their sheer presence in urine cannot be directly linked to an illicit administration. Here, the determination of urinary concentrations and concentration ratios proved to be a suitable tool to identify abnormal steroid profiles. Due to the large inter-individual variability of both concentrations and ratios, population-based thresholds demonstrated to be of limited practicability, leading to the introduction of the steroidal module of the Athlete Biological Passport. The passport enabled the generation of athlete-specific individual reference ranges for steroid profile parameters. Besides an increase in sensitivity, several other aspects like sample substitution or numerous confounding factors affecting the steroid profile are addressed by the Athlete Biological Passport-based approach. This narrative review provides a comprehensive overview on current prospects, supporting professionals in sports drug testing and steroid physiology.

Evaluating the in-sewer stability of three potential population biomarkers for application in wastewater-based epidemiology

Endogenous chemicals specific to human metabolism have been suggested to be good candidates for markers of population size in wastewater-based epidemiology (WBE). So far, creatinine is the only endogenous chemical to be assessed against the criteria of in-sewer stability. This study thus aimed to evaluate the fate of three other endogenous compounds, 5-hydroxy indole acetic acid (5-HIAA), cortisol and androstenedione, under different sewer conditions using laboratory-scale sewer reactors. The results showed that while all compounds were stable in wastewater only (i.e. without biofilm), cortisol and androstenedione degraded quickly in sewers with the presence of sewer biofilms. The degradation followed first-order kinetics similar to that of creatinine. In contrast, 5-HIAA was relatively stable in sewer reactors. This study also recognised the impact of wastewater pH on the detectability of 5-HIAA using a LC-MS/MS direct injection method. In samples acidified to pH 2, the method did not allow routine detection/quantification of 5-HIAA whereas in non-acidified samples the method was sufficiently sensitive for routine quantification of 5-HIAA. The stability of 5-HIAA in sewers and the possibility to measure it using a simple and rapid analytical method corroborate that 5-HIAA may be a suitable biomarker for estimation of population size in WBE.

Epiandrosterone sulfate prolongs the detectability of testosterone, 4-androstenedione, and dihydrotestosterone misuse by means of carbon isotope ratio mass spectrometry

In the course of investigations into the metabolism of testosterone (T) by means of deuterated T and hydrogen isotope ratio mass spectrometry, a pronounced influence of the oral administration of T on sulfoconjugated steroid metabolites was observed. Especially in case of epiandrosterone sulfate (EPIA_S), the contribution of exogenous T to the urinary metabolite was traceable up to 8 days after a single oral dose of 40 mg of T. These findings initiated follow-up studies on the capability of EPIA_S to extend the detection of T and T analogue misuse by carbon isotope ratio (CIR) mass spectrometry in sports drug testing. Excretion study urine samples obtained after transdermal application of T and after oral administration of 4-androstenedione, dihydrotestosterone, and EPIA were investigated regarding urinary concentrations and CIR. With each administered steroid, EPIA_S was significantly depleted and prolonged the detectability when compared to routinely used steroidal target compounds by a factor of 2 to 5. In order to simplify the sample preparation procedure for sulfoconjugated compounds, enzymatic cleavage by Pseudomonas aeruginosa arylsulfatase was tested and implemented into CIR measurements for the first time. Further simplification was achieved by employing multidimensional gas chromatography to ensure the required peak purity for CIR determinations, instead of sample purification strategies using liquid chromatographic fractionation. Taking into account these results that demonstrate the unique and broad applicability of EPIA_S for the detection of illicit administrations of T or T-related steroids, careful consideration of how this steroid can be implemented into routine doping control analysis appears warranted. Copyright © 2017 John Wiley & Sons, Ltd.

Use of isotope ratio mass spectrometry to differentiate between endogenous steroids and synthetic homologues in cattle: a review

Although substantial technical advances have been achieved during the past decades to extend and facilitate the analysis of growth promoters in cattle, the detection of abuse of synthetic analogs of naturally occurring hormones has remained a challenging issue. When it became clear that the exogenous origin of steroid hormones could be traced based on the (13)C/(12)C isotope ratio of the substances, GC/C/IRMS has been successfully implemented to this aim since the end of the past century. However, due to the costly character of the instrumental setup, the susceptibility of the equipment to errors and the complex and time consuming sample preparation, this method is up until now only applied by a limited number of laboratories. In this review, the general principles as well as the practical application of GC/C/IRMS to differentiate between endogenous steroids and exogenously synthesized homologous compounds in cattle will be discussed in detail, and will be placed next to other existing and to be developed methods based on isotope ratio mass spectrometry. Finally, the link will be made with the field of sports doping, where GC/C/IRMS has been established within the World Anti-Doping Agency (WADA) approved methods as the official technique to differentiate between exogenous and endogenous steroids over the past few years.

Evolving concepts and techniques for anti-doping

Technical advances are being made in many areas of biotechnology and genetics that are facilitating the detection of doping in sport. These improvements have been catalyzed by the need to counter the ever-increasing sophistication of the community of athletes and their retinues who are intent on the illicit use of physical, pharmacological and genetic tools and methods to enhance athletic performance, in contravention of established international ethical and legal standards and of international treaty. The methods described in this article present a partial and general picture of only some of these advances.

Influences of β-HCG administration on carbon isotope ratios of endogenous urinary steroids

Several factors influencing the carbon isotope ratios (CIR) of endogenous urinary steroids have been identified in recent years. One of these should be the metabolism of steroids inside the body involving numerous different enzymes. A detailed look at this metabolism taking into account differences found between steroids excreted as glucuronides or as sulphates and hydrogen isotope ratios of different steroids pointed out possibility of unequal CIR at the main production sites inside the male body - the testes and the adrenal glands. By administration of β-HCG it is possible to strongly stimulate the steroid production within the testes without influencing the production at the adrenal glands. Therefore, this treatment should result in changed CIR of urinary androgens in contrast to the undisturbed pre-treatment values. Four male volunteers received three injections of β-HCG over a time course of 5 days and collected their urine samples at defined intervals after the last administration. Those samples showing the largest response in contrast to the pre-administration urines were identified by steroid profile measurements and subsequent analysed by GC/C/IRMS. CIR of androsterone, etiocholanolone, testosterone, 5α- and 5β-androstanediol and pregnanediol were compared. While pregnanediol was not influenced, most of the investigated androgens showed depleted values after treatment. The majority of differences were found to be statistically significant and nearly all showed the expected trend towards more depleted δ(13)C-values. These results support the hypothesis of different CIR at different production sites inside the human body. The impact of these findings on doping control analysis will be discussed.

Calibration and data processing in gas chromatography combustion isotope ratio mass spectrometry

Compound-specific isotope analysis (CSIA) by gas chromatography combustion isotope ratio mass spectrometry (GCC-IRMS) is a powerful technique for the sourcing of substances, such as determination of the geographic or chemical origin of drugs and food adulteration, and it is especially invaluable as a confirmatory tool for detection of the use of synthetic steroids in competitive sport. We review here principles and practices for data processing and calibration of GCC-IRMS data with consideration to anti-doping analyses, with a focus on carbon isotopic analysis ((13)C/(12)C). After a brief review of peak definition, the isotopologue signal reduction methods of summation, curve-fitting, and linear regression are described and reviewed. Principles for isotopic calibration are considered in the context of the Δ(13)C = δ(13)C(M) - δ(13)C(E) difference measurements required for establishing adverse analytical findings for metabolites (M) relative to endogenous (E) reference compounds. Considerations for the anti-doping analyst are reviewed.

Determination of (13)C/(12)C ratios of endogenous urinary steroids excreted as sulpho conjugates

The application of a comprehensive gas chromatography/combustion/isotope ratio mass spectrometry-based method for the measurement of stable carbon isotopes of endogenous urinary steroids excreted as sulphates is presented. The key element in sample preparation is the consecutive cleanup with high-performance liquid chromatography of underivatized and acetylated steroids, which allows the isolation of seven analytes (pregn-5-ene-3β,17α,20α-triol, etiocholanolone, androsterone, epiandrosterone, dehydroepiandrosterone (DHEA), androst-5-ene-3β,17β-diol and androst-5-ene-3β,17α-diol) from a single urine specimen. These steroids are of particular importance to doping controls as they should enable the sensitive and retrospective detection of DHEA abuse by athletes.Depending on the biological background, the determination limit for all steroids ranges from 5 to 10 ng/mL for a 10 mL specimen. The method is validated by means of linear mixing models for each steroid, which covers the items, repeatability and reproducibility. The specificity was further demonstrated by gas chromatography/mass spectrometry for each analyte, and no influence of the sample preparation or the quantity of analyte on carbon isotope ratios was observed. In order to determine naturally occurring (13)C/(12)C ratios and urinary concentrations of all implemented steroids, a reference population of n = 67 subjects was measured to enable the calculation of reference limits for all relevant steroidal Δ values.The applicability of the developed method was tested by means of a DHEA excretion study. Despite the fact that orally ingested DHEA is preferentially converted into sulphated metabolites and that the renal clearance of sulphated steroids is slow, only the (13)C/(12)C ratio of EpiA demonstrated the potential to prolong the detection time for DHEA misuse.