The athlete biological passport

Comparison of analytical approaches for the detection of oral testosterone undecanoate administration in men

For antidoping laboratories, the determination of an illicit testosterone (T) administration in urine samples remains a difficult process as it requires the determination of the exogenous origin by carbon isotope ratios (CIRs) of testosterone and its metabolites. As a complement to the urinary analysis, targeting testosterone esters (e.g. testosterone undecanoate [TU]) in serum samples by liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) could represent a simpler approach compared with isotope ratio mass spectrometry (IRMS). These two approaches both lead to the direct detection of the administration of exogenous T but with a difference in effort and complexity of the analysis. To compare the detection window obtained with the two strategies, serum and the corresponding urine samples collected from an administration study with oral TU were analysed. Results showed that, at all timepoints where the intact TU was detected in serum, the CIRs of urinary steroids were also not in agreement with an endogenous origin. IRMS analysis required more effort but resulted in slightly longer detection windows than the ester analysis. Finally, this comparison study showed that, in the presence of a suspicious urinary steroid profile, the LC-MS/MS steroid esters analysis in the corresponding serum samples can be very helpful. If steroid esters are not detected, the IRMS analysis can then be conducted on the urine sample afterwards. Overall, the combination of matrices might facilitate the detection of prohibited T administration in sports, especially for athletes with naturally low T/E ratios.

Comparison between standard hematological parameters and blood doping biomarkers in dried blood spots within the athlete population of Swiss Sport Integrity

Introduction

The study demonstrated the feasibility of incorporating RNA biomarkers, specifically 5-aminolevulinic acid synthase (ALAS2) and carbonic anhydrase 1 (CA1), to improve the hematological module of the Athlete Biological Passport (ABP) in routine antidoping context.

Objective

The aim was to investigate the implementation of reticulocyte (RET) related biomarkers, specifically ALAS2 and CA1, using quantitative reverse transcription polymerase chain reaction (RT-qPCR) on dried blood spots (DBS) from elite athletes. Hemoglobin changes over time in DBS samples was measured as well. Combining hemoglobin and messenger RNA (mRNA) analyses allowed to monitor alterations of the established marker, "DBS OFF-score".

Methodology

Ten athletes were selected for sampling by the Swiss national antidoping organization, Swiss Sports Integrity (SSI). Samples were collected, transported and analyzed for ABP following the World Anti-Doping Agency (WADA) procedures and spotted onto Protein Saver DBS cards.

Results

Most athletes exhibited stable biomarker levels, except for one individual involved in ski mountaineering, who demonstrated a sustained increase in ALAS2 compared to the individual baseline. This elevation could be due to blood withdrawal or other factors, such as doping with substances outside the targeted test menu.

Conclusion

In this study, RNA-biomarkers were successfully analyzed in routine blood samples, and the project demonstrated promising results for the implementation of ALAS2 and CA1 in routine analysis to complement the ABP.

Antidoping 2.0: Is Adding Power-Output Data to the Antidoping Pool the Next Step? Experts' Viewpoint

BACKGROUND

Efforts are needed to improve antidoping procedures. The widespread use of power meters among cyclists could help in this regard. However, controversy exists on whether performance monitoring through power-output data could be of help for antidoping purposes.

PURPOSE

The objective of the present study was to provide insight into the feasibility and utility of implementing power-based performance monitoring in elite cycling. An expert panel of 15 applied sport scientists and professional cycling coaches were asked for their opinions and perspectives on incorporating power data into the antidoping risk-assessment process.

RESULTS

Two different viewpoints were identified from the responses provided by the experts. Some believed that power monitoring could be implemented as an antidoping tool, provided that several surmountable challenges are first addressed. These authors provided suggestions related to the potential practical implementation of such measures. Others, on the contrary, believed that power meters lack sufficient reliability and suggest that the professional cycling world presents conflicts of interest that make this intervention impossible to implement nowadays.

CONCLUSIONS

The debate around the utility of power-meter data in the antidoping fight has been ongoing for more than a decade. According to the opinions provided by the experts' panel, there is still no consensus on the real utility and practical implementation of this intervention.

An enhanced label-free proteomics approach for deep-diving into equine plasma proteome, including the discovery of protein biomarkers for strenuous exercise

Plasma proteins have been a valuable source of biomarkers for clinical uses and for monitoring of the illicit use of prohibited substances or practices in equine sports. We have previously reported the first use of label-free proteomics in profiling equine plasma proteome. This study aimed to refine the method by systematically evaluating various plasma fractionation methods and the use of narrower precursor mass ranges in data-independent acquisition (DIA) mass spectrometry (MS). Tandem fractionations of equine plasma with octanoic acid precipitation followed by solid-phase extraction (SPE) with C4 cartridges provided the largest increase in the number of new proteins identified. The use of two narrow precursor mass ranges of m/z 400-600 and 600-800 in DIA not only identified most proteins detectable by using a single mass range of m/z 350-1500 but also identified ~27% more proteins. The improved method was applied to analyse the plasma proteome of 'postrace' samples which, unlike other samples, had been collected from racehorses soon after racing. Multivariate data analysis has identified upregulation of 14 proteins and downregulation of six proteins in postrace plasma compared with the non-postrace plasma samples. Literature review of these proteins has provided evidence of exercise-induced haemolysis and changes in antioxidant enzyme activities, kinin system, insulin signalling and energy metabolism after strenuous exercise. The improved method has enabled a deeper profiling of the equine plasma proteome and identified the proteins associated with normal physiological changes after racing which are potential confounding factors in the development of a biomarker approach for doping control.

Biological Variation Data in Triathletes for Metabolism and Growth-Related Biomarkers Included in the Athlete Biological Passport

BACKGROUND

When using biological variation (BV) data, BV estimates need to be robust and representative. High-endurance athletes represent a population under special physiological conditions, which could influence BV estimates. Our study aimed to estimate BV in athletes for metabolism and growth-related biomarkers involved in the Athlete Biological Passport (ABP), by 2 different statistical models.

METHODS

Thirty triathletes were sampled monthly for 11 months. The samples were analyzed for human growth hormone (hGH), insulin-like growth factor-1 (IGF-1), insulin-like growth factor binding protein 3 (IGFBP-3), insulin, and N-terminal propeptide of type III procollagen (P-III-NP) by immunoassay. Bayesian and ANOVA methods were applied to estimate within-subject (CVI) and between-subject BV.

RESULTS

CVI estimates ranged from 7.8% for IGFBP-3 to 27.0% for insulin, when derived by the Bayesian method. The 2 models gave similar results, except for P-III-NP. Data were heterogeneously distributed for P-III-NP for the overall population and in females for IGF-1 and IGFBP-3. BV components were not estimated for hGH due to lack of steady state. The index of individuality was below 0.6 for all measurands, except for insulin.

CONCLUSIONS

In an athlete population, to apply a common CVI for insulin would be appropriate, but for IGF-1 and IGFBP-3 gender-specific estimates should be applied. P-III-NP data were heterogeneously distributed and using a mean CVI may not be representative for the population. The high degree of individuality for IGF-1, IGFBP-3, and P-III-NP makes them good candidates to be interpreted through reference change values and the ABP.

Liquid vs dried blood matrices: Application to longitudinal monitoring of androstenedione, testosterone, and IGF-1 by LC-MS-based techniques

BACKGROUND

Dried blood spots have recently been approved by the World Anti-Doping Agency as an alternative biological matrix for testing of doping substances. However, their use is limited to the detection of non-threshold compounds without a Minimum Reporting Level due to the numerous issues related to quantitative analyses and the limitation on testing capabilities of a haemolysed matrix.

AIM

In this study androstenedione, testosterone and IGF-1 were longitudinally monitored in four different blood matrices to evaluate the potential of liquid capillary blood as an alternative matrix for quantitative determination in doping control analysis.

METHODOLOGY

The analytical protocols developed to pretreat 20 μL of the blood matrices selected were based: i) for testosterone and androstenedione, on supported liquid extraction for liquid blood matrices, and on ultrasonication in the presence of methanol for dried blood matrices; ii) for IGF-1, proteins precipitation followed by evaporation of the supernatant was used to pretreat both liquid and dried blood matrices. The detection for all the target analytes was performed using liquid chromatography coupled to mass spectrometry. The analytical workflows, once optimized, were fully validated according to the requirements of World Anti-Doping Agency and ISO 17025 standard and used for the analysis of venous (serum) and capillary (liquid plasma and dried whole blood collected using either volumetric or non-volumetric devices) blood samples collected from 7 healthy subjects.

RESULTS

The validation results showed satisfactory performance as related to specificity, sensitivity, matrix effects, linearity, accuracy, and precision in all the blood matrices evaluated despite the limited volume of sample used. The analysis of the different blood matrices collected from the subjects showed non-significant differences between the levels of testosterone and androstenedione measured in dried (fixed volume collected) and liquid matrices. An acceptable underestimation (lower than 15 %) was observed in capillary plasma compared to venous serum. The testosterone/androstenedione ratio was similar in all the blood matrices considered (bias lower than 5 %), indicating this parameter was not affected by either the blood matrix or collection device selected. For IGF-1, the levels measured in liquid blood matrices differed significantly (bias higher than 20 %) from those measured in dried whole blood matrices, suggesting haemolyzed blood might represent a challenge for the determination of macromolecules, mainly due to the complexity of the whole blood matrix in comparison to plasma/serum.

NOVELTY

The outcomes of our study suggest that liquid capillary blood might open new avenues to blood microsampling in doping control field. It represents an efficient alternative to overcome the issues related to venous blood and dried blood spot sampling. Furthermore, it also allows greater frequency of blood sampling, with minor discomfort and without needing a phlebotomist, for analyses that can only be performed in blood samples, with an increased probability to detect and report Adverse Analytical Finding.

Establishing Personalized Blood Protein Reference Ranges Using Noninvasive Microsampling and Targeted Proteomics: Implications for Antidoping Strategies

To prevent doping practices in sports, the World Anti-Doping Agency implemented the Athlete Biological Passport (ABP) program, monitoring biological variables over time to indirectly reveal the effects of doping rather than detect the doping substance or the method itself. In the context of this program, a highly multiplexed mass spectrometry-based proteomics assay for 319 peptides corresponding to 250 proteins was developed, including proteins associated with blood-doping practices. "Baseline" expression profiles of these potential biomarkers in capillary blood (dried blood spots (DBS)) were established using multiple reaction monitoring (MRM). Combining DBS microsampling with highly multiplexed MRM assays is the best-suited technology to enhance the effectiveness of the ABP program, as it represents a cost-effective and robust alternative analytical method with high specificity and selectivity of targets in the attomole range. DBS data were collected from 10 healthy athlete volunteers over a period of 140 days (28 time points per participant). These comprehensive findings provide a personalized targeted blood proteome "fingerprint" showcasing that the targeted proteome is unique to an individual and likely comparable to a DNA fingerprint. The results can serve as a baseline for future studies investigating doping-related perturbations.

Use of RNA biomarkers in the antidoping field

There is growing evidence that various RNA molecules can serve as biomarkers for clinical diagnoses. Over the last decade, the high specificities and sensitivities of RNA biomarkers have led to proposals that they could be used to detect prohibited substances and practices in sports. mRNAs and circulating miRNAs have the potential to improve the detection of doping and expand the performance of the Athlete Biological Passport. This review provides a summary of the use of RNA biomarkers to detect human and equine doping practices, including a discussion of the use of dried blood spots as a stable matrix that supports and improves the general process of RNA biomarker detection. The advantages of RNA biomarkers over protein biomarkers are also discussed.

Performance-enhancing substances in sport: A scientometric review of 75 years of research

The use of performance-enhancing substances not only undermines the core values of sports but also poses significant health risks to athletes. In a fast-evolving doping environment, where sport professionals are constantly seeking novel and illegal means to bypass doping tests, and new substances are regularly detected on the drug market, it is crucial to inform authorities with updated evidence emerging from scientific research. The current study aims to (i) outline the structure of knowledge in the literature on performance enhancers in sports (i.e., most active countries, main sources, most productive authors, and most frequently used keywords); (ii) identify the most impactful documents in the field; and (iii) uncover the main domains of research in the literature. To do so, we conducted a comprehensive scientometric analysis of the literature on doping, sourcing our data from Scopus. Our research involved a document co-citation analysis of 193,076 references, leading to the identification of the 51 most influential documents and seven key thematic areas within the doping literature. Our results indicate that the scientific community has extensively studied the most prevalent doping classes, such as anabolic agents and peptide hormones, and little is still known about the use of contaminated supplements or other types of enhancers identified as emergent trends. Concurrently, technological advancements contributed to the development of more sophisticated doping detection techniques, using blood or urine samples. More recently, the focus has shifted towards the athlete biological passport, with research efforts aimed at identifying biomarkers indicative of doping. The dynamic nature of doping methods underlines the necessity for more robust educational campaigns, aiming at raising awareness among sports professionals and their entourage about the dangers of doping and the intricacies of its control mechanisms.

Homologous blood transfusion and doping: Where are we now?

Homologous blood transfusion (HBT) is used for doping in endurance sports since the 1960s. The blood comes from a compatible donor, that is, someone with a compatible ABO and rhesus blood group. Despite been prohibited by the IOC in 1985, no detection method was available until 2003. Then came the idea to use red blood cells (RBC) minor blood groups antigens that constitute an "identity" card of someone's RBC to detect the presence of a second RBC population. The method validated for doping control samples uses flow cytometry after incubation of isolated RBC with eight to 12 primary antibodies against specific minor blood groups antigens. The presence of double populations of RBC is revealed by a major and a minor peak in a fluorescence histogram. The sensitivity was estimated sufficient to detect HBT for a few weeks. Despite the complexity and cost of the method, right after its application in 2004, several cases of HBT were identified but the number of cases dropped rapidly over the years. In the 2010s, other ways to detect HBT were developed and evaluated: indirect detection using the Athlete Biological Passport approach, and a few years later forensic DNA analysis to establish the presence of two different DNA in a blood sample after HBT. Despite the high specificity of the latter, the sensitivity was recently questioned in vivo. Nowadays, the flow cytometry method remains the method of choice for HBT detection and recent investigations helped to simplify the method and increase its specificity and sensitivity.

Yearly intrasubject variability of hematological biomarkers in elite athletes for the Athlete Biological Passport

Confounding factors including exercise and environments challenge the interpretation of individual Athlete Biological Passports (ABPs). This study aimed to investigate the natural variability of hematological ABP parameters over 1 year in elite athletes compared with healthy control subjects and the validity of a multiparametric model estimating plasma volume (PV) shifts to correct individual ABP thresholds. Blood samples were collected monthly with full blood counts performed by flow cytometry (Sysmex XN analyzers) in 20 elite xc-skiers (ELITE) and 20 moderately trained controls. Individual ABP profiles were generated through Anti-Doping Administration & Management System Training, a standalone version of the ABP's adaptive model developed by the World Anti-Doping Agency. Additionally, eight serum parameters were computed as volume-sensitive biomarkers to run a multiparametric model to estimate PV. Variability in ELITE compared with controls was significantly higher for the Abnormal Blood Profile Scores (P = 0.003). Among 12 Atypical Passport Findings (ATPF) initially reported, six could be removed after correction of PV shifts with the multiparametric modeling. However, several ATPF were additionally generated (n = 19). Our study outlines a larger intraindividual variability in elite athletes, likely explained by more frequent exposure to extrinsic factors altering hematological biomarkers. PV correction for individual ABP thresholds allowed to explain most of the atypical findings while generating multiple new ATPF occurrences in the elite population. Overall, accounting for PV shifts in elite athletes was shown to be paramount in this study outlining the opportunity to consider PV variations with novel approaches when interpreting individual ABP profiles.

Indirect biomarkers of blood doping: A systematic review

The detection of blood doping represents a current major issue in sports and an ongoing challenge for antidoping research. Initially focusing on direct detection methods to identify a banned substance or its metabolites, the antidoping effort has been progressively complemented by indirect approaches. The longitudinal and individual monitoring of specific biomarkers aims to identify nonphysiological variations that may be related to doping practices. From this perspective, the identification of markers sensitive to erythropoiesis alteration is key in the screening of blood doping. The current Athlete Biological Passport implemented since 2009 is composed of 14 variables (including two primary markers, i.e., hemoglobin concentration and OFF score) for the hematological module to be used for indirect detection of blood doping. Nevertheless, research has continually proposed and investigated new markers sensitive to an alteration of the erythropoietic cascade and specific to blood doping. If multiple early markers have been identified (at the transcriptomic level) or developed directly in a diagnostics' kit (at a proteomic level), other target variables at the end of the erythropoietic process (linked with the red blood cell functions) may strengthen the hematological module in the future. Therefore, this review aims to provide a global systematic overview of the biomarkers considered to date in the indirect investigation of blood doping.

Adaptive data collection for intraindividual studies affected by adherence

Recently, the use of mobile technologies in ecological momentary assessments (EMAs) and interventions has made it easier to collect data suitable for intraindividual variability studies in the medical field. Nevertheless, especially when self-reports are used during the data collection process, there are difficulties in balancing data quality and the burden placed on the subject. In this paper, we address this problem for a specific EMA setting that aims to submit a demanding task to subjects at high/low values of a self-reported variable. We adopt a dynamic approach inspired by control chart methods and design optimization techniques to obtain an EMA triggering mechanism for data collection that considers both the individual variability of the self-reported variable and of the adherence. We test the algorithm in both a simulation setting and with real, large-scale data from a tinnitus longitudinal study. A Wilcoxon signed rank test shows that the algorithm tends to have both a higher F1 score and utility than a random schedule and a rule-based algorithm with static thresholds, which are the current state-of-the-art approaches. In conclusion, the algorithm is proven effective in balancing data quality and the burden placed on the participants, especially in studies where data collection is impacted by adherence.

A new multimodal paradigm for biomarkers longitudinal monitoring: a clinical application to women steroid profiles in urine and blood

BACKGROUND

Most current state-of-the-art strategies to generate individual adaptive reference ranges are designed to monitor one clinical parameter at a time. An innovative methodology is proposed for the simultaneous longitudinal monitoring of multiple biomarkers. The estimation of individual thresholds is performed by applying a Bayesian modeling strategy to a multivariate score integrating several biomarkers (compound concentration and/or ratio). This multimodal monitoring was applied to data from a clinical study involving 14 female volunteers with normal menstrual cycles receiving testosterone via transdermal route, as to test its ability to detect testosterone administration. The study samples consisted of urine and blood collected during 4 weeks of a control phase and 4 weeks with a daily testosterone gel application.

RESULTS

Integrating multiple biomarkers improved the detection of testosterone gel administration with substantially higher sensitivity compared with the distinct follow-up of each biomarker, when applied to selected urine and serum steroid biomarkers, as well as the combination of both. Among the 175 known positive samples, 38% were identified by the multimodal approach using urine biomarkers, 79% using serum biomarkers and 83% by combining biomarkers from both biological matrices, whereas 10%, 67% and 64% were respectively detected using standard unimodal monitoring.

SIGNIFICANCE AND NOVELTY

The detection of abnormal patterns can be improved using multimodal approaches. The combination of urine and serum biomarkers reduced the overall number of false-negatives, thus evidencing promising complementarity between urine and blood sampling for doping control, as highlighted in the case of the use of transdermal testosterone preparations. The generation in a multimodal setting of adaptive and personalized reference ranges opens up new opportunities in clinical and anti-doping profiling. The integration of multiple parameters in a longitudinal monitoring is expected to provide a more complete evaluation of individual profiles generating actionable intelligence to further guide sample collection, analysis protocols and decision-making in clinics and anti-doping.

Longitudinal Profiling of Endogenous Steroids in Blood Using the Athlete Biological Passport Approach

CONTEXT

Detection of endogenous anabolic androgenic steroids (EAAS), like testosterone (T), as doping agents has been improved with the launch of the Steroidal Module of the Athlete Biological Passport (ABP) in urine samples.

OBJECTIVE

To target doping practices with EAAS, particularly in individuals with low level of biomarkers excreted in urine, by including new target compounds measured in blood.

DESIGN

T and T/androstenedione (T/A4) distributions were obtained from 4 years of anti-doping data and applied as priors to analyze individual profiles from 2 T administration studies in female and male subjects.

SETTING

Anti-doping laboratory. Elite athletes (n = 823) and male and female clinical trials subjects (n = 19 and 14, respectively).

INTERVENTION(S)

Two open-label administration studies were carried out. One involved a control phase period followed by patch and then oral T administration in male volunteers and the other followed female volunteers during 3 menstrual cycles with 28 days of daily transdermal T application during the second month.

MAIN OUTCOME MEASURE(S)

Serum samples were analyzed for T and A4 and the performance of a longitudinal ABP-based approach was evaluated for T and T/A4.

RESULTS

An ABP-based approach set at a 99% specificity flagged all female subjects during the transdermal T application period and 44% of subjects 3 days after the treatment. T showed the best sensitivity (74%) in response to transdermal T application in males.

CONCLUSIONS

Inclusion of T and T/A4 as markers in the Steroidal Module can improve the performance of the ABP to identify T transdermal application, particularly in females.

Capillary blood as a complementary matrix for doping control purposes. Application to the definition of the individual longitudinal profile of IGF-1

We present a novel procedure to monitor the fluctuations of the levels of IGF-1 in capillary blood in the framework of doping control analysis. Being an endogenous hormone, direct methods are not applicable, so the most effective way to detect the intake of the exogenous hormone would be based on the longitudinal monitoring of the athlete. We have therefore followed the individual variability, in four subjects (two males and two females), of the levels of IGF-1 in capillary blood samples collected three times per day for five days, then once a week for at least two months. Analyses were performed by liquid chromatography coupled to tandem mass spectrometry following a bottom-up approach. The whole protocol, from the sample collection to the instrumental analysis, was validated according to the World Anti-Doping Agency's guidelines and ISO17025. The analytical protocol showed to be fit for purpose in terms of sensitivity (LOD 25 ng/mL and LOI 35 ng/mL), selectivity (no interferences were detected at the retention time of IGF-1 and the internal standard), and repeatability (CV<10%). The linearity was confirmed in the range of 50-1000 ng/mL (correlation coefficient R² >0.995, with a % relative bias of the experimental concentration of the different calibrators used for the estimation of the linearity lower than 20% for the lowest level and than 15% for the other levels). Stability studies were also performed, also to establish the optimal conditions for transport and storage: samples were stable at 4 °C for up to 72 h and at -20 °C and -80 °C for up to three months. Our preliminary results indicate that, in all subjects, the levels of IGF-1 did not present significant circadian fluctuations and remained stable during the entire period of the study (2-3 months, depending on the subject). The stability over time of IGF-1 levels in capillary blood indicates the possibility of detecting the intake of the non-endogenous hormone based on a longitudinal approach, as it is modeled in the framework of the endocrinological module of the athlete biological passport.

Intelligence-based doping control planning improves testing effectiveness: Perspectives from a national anti-doping organisation

Anti-doping organisations are mandated to provide a comprehensive anti-doping programme, which aims to detect, deter and prevent doping in sport. Direct detection of prohibited substances and methods by collection of biological samples from athletes makes up about half of the global anti-doping budgets but has in the last decade been under critical scrutiny for its lack of efficiency. To ensure optimum detection and deterrence of testing and prevention efforts, a better understanding of doping practices and comparison of different doping test strategies are needed. This study evaluates 17 years of doping test statistics and Anti-Doping Rule Violations (ADRVs) from the perspectives of a national anti-doping organisation. A total of 48 709 samples (2865 ± 220 annually) were collected by Anti-Doping Norway in the period 2003-2019, which resulted in total 216 ADRVs (12.7 ± 3.7 annually), providing an average sample-to-ADRV rate of 0.44% when including urine, blood and ABP samples. Most athletes who committed ADRVs were men participating in ball and team or strength sports at a national or recreational level. Few ADRVs were recorded among elite athletes and in most high-risk sports, despite these groups being subjected to the highest number of doping tests. The number of annual ADRVs did not correlate with the corresponding number of collected doping samples. However, systematic use of intelligence in the test planning process was associated with an increase in ADRVs. Anti-doping organisations would benefit from improving their target testing capability and to take an intelligence-led approach in planning doping tests.

Future opportunities for the Athlete Biological Passport

The Athlete Biological Passport (ABP) was introduced to complement the direct anti-doping approach by indirectly outlining the possible use of prohibited substances or methods in sports. The ABP proved its effectiveness, at least through a deterrent effect, even though the matrices used for longitudinal monitoring (urine and blood) are subject to many intrinsic (e.g., genetic) and extrinsic (e.g., environmental conditions) confounding factors. In that context, new and more specific biomarkers are currently under development to enhance both the sensitivity and the specificity of the ABP. Multiple strategies are presently being explored to improve this longitudinal monitoring, with the development of the current modules, the investigation of new strategies, or the screening of new types of doping. Nevertheless, due to the variability induced by indirect biomarkers, the consideration of confounding factors should continuously support this research. Beyond tremendous advances in analytical sensitivity, machine learning-based approaches seem inevitable to facilitate an expert interpretation of numerous biological profiles and promote anti-doping efforts. This perspective article highlights the current innovations of the Athlete Biological Passport that seem the most promising. Through different research axes, this short manuscript provides an opportunity to bring together approaches that are more widely exploited (e.g., omics strategies) and others in the early stages of investigation (e.g., artificial intelligence) seeking to develop the ABP.

Reliability of Drug History to Verify Androgen Abuse in Men

CONTEXT

Clinical evaluations that require excluding androgen abuse, a secretive, illicit activity, rely on the drug history, but its veracity for androgen abuse has neither been verified nor has any objective corroborating laboratory test been validated.

OBJECTIVE

In a high-risk population, to (a) validate the drug history of androgen abuse objectively using state-of-the-art World Anti-Doping Agency-accredited antidoping laboratory urine mass spectrometry tests and (b) to determine what biochemical tests best distinguish androgen abuse from nonuse in this population.

METHODS

Urine samples from current (n = 41) and past (n = 31) androgen abusers and nonusers (n = 21) were analyzed by comprehensive mass spectrometry-based detection tests for androgens and related drugs (ARD).

RESULTS

No prohibited ARDs were identified among nonusers. Current users had a median of 5 (range 1-13) drugs detected comprising 176 ARDs among 220 drug identifications. Past users had a median of 1 (range 0-9) drugs detected comprising 21 ARDs among 43 drugs. Negative predictive value was high (>0.8) for those denying drug usage while positive predictive value was good (>0.6) for both those reporting currently using (current) and not using (nonusers plus past users) ARD. Serum luteinizing hormone (LH) alone had high, but imperfect, discriminatory power (89%) to distinguish between current and noncurrent androgen use.

CONCLUSIONS

We demonstrates that a negative drug history in a high-risk group has high reliability and that even a single suppressed serum LH exhibits high discrimination for objectively detecting androgen abuse.

Ten years of collecting hematological athlete biological passport samples—perspectives from a National Anti-doping Organization

The hematological module of the Athlete Biological Passport (ABP) aims to reveal blood doping indirectly by looking at selected biomarkers of doping over time. For Anti-Doping Organizations (ADOs), the ABP is a vital tool in the fight against doping in sports through improved target testing and analysis, investigations, deterrence, and as indirect evidence for use of prohibited methods or substances. The physiological characteristics of sport disciplines is an important risk factor in the overall risk assessment and when implementing the hematological module. Sharing of experiences with implementing the hematological ABP between ADOs is key to further strengthen and extend its use. In this study, we present 10 years of experience with the hematological ABP program from the perspectives of a National ADO with special attention to sport disciplines' physiological characteristics as a potential risk factor for blood doping. Not surprisingly, most samples were collected in sport disciplines where the aerobic capacity is vital for performance. The study highlights strengths in Anti-Doping Norway's testing program but also areas that could be improved. For example, it was shown that samples were collected both in and out of season in a subset of the data material that included three popular sports in Norway (Cross-Country Skiing, Nordic Combined, and Biathlon), however, from the total data material it was clear that athletes were more likely to be tested out of competition and on certain days of the week and times of the day. The use of doping control officers with a flexible time schedule and testing outside an athlete's 60 min time-slot could help with a more even distribution during the week and day, and thus reduce the predictability of testing. In addition to promoting a discussion on testing strategies, the study can be used as a starting point for other ADOs on how to examine their own testing program.

Altitude and Erythropoietin: Comparative Evaluation of Their Impact on Key Parameters of the Athlete Biological Passport: A Review

The hematological module of the Athlete's Biological Passport (ABP) identifies doping methods and/or substances used to increase the blood's capacity to transport or deliver oxygen to the tissues. Recombinant human erythropoietin (rhEPOs) are doping substances known to boost the production of red blood cells and might have an effect on the blood biomarkers of the ABP. However, hypoxic exposure influences these biomarkers similarly to rhEPOs. This analogous impact complicates the ABP profiles' interpretation by antidoping experts. The present study aimed to collect and identify, through a literature search, the physiological effects on ABP blood biomarkers induced by these external factors. A total of 43 studies were selected for this review. A positive correlation (R² = 0.605, r = 0.778, p < 0.001) was identified between the hypoxic dose and the increase in hemoglobin concentration (HGB) percentage. In addition, the change in the reticulocyte percentage (RET%) has been identified as one of the most sensitive parameters to rhEPO use. The mean effects of rhEPO on blood parameters were greater than those induced by hypoxic exposure (1.7 times higher for HGB and RET% and 4 times higher for hemoglobin mass). However, rhEPO micro-doses have shown effects that are hardly distinguishable from those identified after hypoxic exposure. The results of the literature search allowed to identify temporal and quantitative evolution of blood parameters in connection with different hypoxic exposure doses, as well as different rhEPOs doses. This might be considered to provide justified and well-documented interpretations of physiological changes in blood parameters of the Athlete Biological Passport.

Engaging community pharmacists to eliminate inadvertent doping in sports: A study of their knowledge on doping

This study aimed to evaluate the community pharmacists’ knowledge of tackling the issue of inadvertent doping in Malaysia. A cross-sectional survey was conducted among 384 community pharmacists working in Malaysia using a self-administered questionnaire. All the respondents were pharmacists fully registered with the Pharmacy Board of Malaysia and had been working in the community setting for at least one year. Of the 426 community pharmacists approached, 384 community pharmacists participated in this study, giving a response rate of 90.14%. The majority of the respondents were females (63.5%), graduated from local universities (74.9%), with median years of practising as a community pharmacist of six years (interquartile range, IQR = 9 years). The respondents were found to have moderate levels of doping-related knowledge (median score of 52 out of 100). Anabolic steroids (95.8%), stimulants (78.6%) and growth factors (65.6%) were recognised as prohibited substances by most of the respondents. Around 65.9% did not recognise that inadvertent doping is also considered a doping violation. Most of them (90%) also have poor levels of knowledge of doping scenarios in the country. Community pharmacists in Malaysia have limited knowledge in the field of doping. More programmes and activities related to doping and drugs in sports should be held to enhance the community pharmacists’ knowledge on the issue of inadvertent doping.

Importance of weightlifting performance analysis in anti-doping

We examined the potential roles of the athlete’s performance passport (APP) for doping detection by analyzing the relationship between weightlifting performance and sanction status. For the present study, performance data of ‘not-sanctioned’ (26740 datasets) and ‘sanctioned’ (289 datasets) male athletes were acquired from the website of the International Weightlifting Federation (www.iwf.net). One-way ANOVA, correlation analysis, and t-tests were used to analyze the relationship between athletes’ use of doping and their performances across age and body weight. Athletic performance was significantly greater for athletes in the sanctioned group than those of the same age group who were not sanctioned, and this performance difference between the two groups was the greatest in their late thirties at 20.6% (not-sanctioned 292.0kg vs. sanctioned 352.3kg) (p < 0.05). From the age group analysis, out of 289 sanctioned cases, 84 cases, which was the largest proportion, were found within the top 10–25% of their performances. When stratified by body weight, athletic performance was significantly greater for the sanctioned group than the not-sanctioned group, and this performance gap was the greatest in the bodyweight category of 96 at 18.6% (not-sanctioned 310.1kg vs. sanctioned 367.8kg) (p < 0.05). From the body weight category analysis, out of 289 sanctioned cases, 75 cases, which was the largest proportion, were found within the top 10–25% of their performances. Additionally, the mean difference in performance between not-sanctioned and sanctioned groups was the largest in the body weight category of 67kg in the ages of 15–19 at 20% (not-sanctioned 234.6kg vs. sanctioned 281.5kg). These results are interpreted to mean that in male weightlifters 1) sanctioned athletes were detected in all ranges of performances regardless of age and body weight, 2) there were even higher rates of sanctioned athletes who performed within the top 10–25% of each age group and body weight category, 3) there were significant differences in performance between not-sanctioned and sanctioned group for all body weight categories, excluding +109, in the ages of 15–19 and 20–24, 4) therefore, performance data can be effectively used to better target suspected athletes for doping testing.

Support of a laboratory-hosted Athlete Biological Passport Management Unit (APMU) to the anti-doping organisations

The athlete biological passport (ABP) is an established means for longitudinal monitoring of selected individual biomarkers of an athlete to obtain indirect but potentially long-term indications of the use of substances or methods prohibited in sport. Along the change from population-based reference values to individual profiling, the ABP aims at triggering follow-up investigations concerning the potential use of endogenous substances with doping potential, which might be difficult either to identify with the existing analytical methods or to interpret based only on the results of a single biological sample. The ABP program has been on-going within the World Anti-Doping Agency (WADA) management since 2009, when the hematological module was officially established to discover blood doping practices, such as administration of erythropoietin (EPO) or application of blood transfusion. Since 2014, the ABP has been complemented by the steroid module, with the aim of targeting the prohibited use of testosterone and other endogenous anabolic androgenic steroids with performance enhancing or masking capability. Although the main objective is to guide and assist the anti-doping organizations in their test distribution plans, the ABP may also be used to proceed with a case to an anti-doping rule violation. Evaluation of biological markers, especially in distinguishing between doping from other confounding factors, requires high level and diversity of expertise, which is coordinated by the athlete biological passport management unit (APMU). Since 2019, the WADA accredited anti-doping laboratories are defined as the host organizations for the APMUs. The benefit of such a structure is to obtain a fully anonymous evaluation process for the passports and an additional level of expertise for the interpretation of analytical results as well as to have a fluent communication line with the analyzing laboratories when further details are needed for the analytical testing and documentation.

Cross-platform transcriptomic profiling of the response to recombinant human erythropoietin

RNA-seq has matured and become an important tool for studying RNA biology. Here we compared two RNA-seq (MGI DNBSEQ and Illumina NextSeq 500) and two microarray platforms (GeneChip Human Transcriptome Array 2.0 and Illumina Expression BeadChip) in healthy individuals administered recombinant human erythropoietin for transcriptome-wide quantification of differential gene expression. The results show that total RNA DNB-seq generated a multitude of target genes compared to other platforms. Pathway enrichment analyses revealed genes correlate to not only erythropoiesis and oxygen transport but also a wide range of other functions, such as tissue protection and immune regulation. This study provides a knowledge base of genes relevant to EPO biology through cross-platform comparisons and validation.

Standardization of reticulocyte counts in the athlete biological passport: A practical update

INTRODUCTION

The athlete biological passport monitors blood variables over time to uncover blood doping. With the phasing in of a new series of blood analyzers, the Sysmex XN series, it was necessary to examine the comparability of results with the previously employed XT/XE series. A previous comparison between XN and XT/XE series suggested a small but significant bias between the two instruments in the measurements of RET%. Here, we examined the comparability of RET% on the XN and XT/XE platform using data collected over the first year since the transition.

METHODS

The comparability of results obtained from XN and XT/XE instruments was assessed using three datasets: (i) 767 blood samples measured on both instrument series in 22 WADA-accredited laboratories, (ii) 27 323 samples measured on either instrument across 31 laboratories, and (iii) 119 clinical samples and 110 anti-doping samples measured on both instruments in a single laboratory.

RESULTS

Analysis of the three datasets confirms the previous observation of a bias toward higher RET% values for samples measured on Sysmex XN instruments compared with the XT/XE series. Using data across a larger number of XN instruments and a larger athlete population, the current work suggests that the bias is proportional and slightly higher than previously observed across most of the range RET% values.

CONCLUSION

A model is proposed for the comparison of data across XN and XT/XE technologies whereby the instrument bias increases proportionally with RET% measured on Sysmex XN Series, but where the rate of increase is negatively related to IRF%.

Influence of synthetic isoflavones on selected urinary steroid biomarkers: Relevance to doping control

In this work we have investigated the influence of the intake of two synthetic isoflavones, methoxyisoflavone and ipriflavone, on the urinary concentration of endogenous steroids, and on their relative ratios, of doping relevance. Specifically, the concentrations of testosterone (T), epitestosterone (E), androsterone (A), etiocholanolone (Etio), 5α-androstan-3α,17α-diol (5αAdiol), 5β-androstan-3α,17α-diol (5βAdiol), and the ratios T/E, A/T, A/Etio, 5αAdiol/5βAdiol, 5αAdiol/E, were considered, in the framework of the Steroidal Module of the Athlete Biological Passport (ABP). The above set of parameters were complemented by the urinary levels of luteinizing hormone (total LH) and the ratio between T and LH (T/total LH), to assess the possible effects on the biosynthesis of the mentioned steroids. Five healthy Caucasian male volunteers were selected for the study. Urine samples were collected before and during the administration of (i) methoxyisoflavone (Methoxyisoflavone, MyProtein) and (ii) ipriflavone (Osteofix ®, Chiesi Farmaceutici). For the analysis of the urinary steroid profile, after enzymatic hydrolysis with β-glucuronidase from Escherichia Coli (E. Coli) and liquid-liquid extraction with tert-buthylmethyl ether, all samples were analyzed by gas chromatography coupled to tandem mass spectrometry (GC-MS/MS), while for the determination of total LH all urine samples were directly analyzed by a chemiluminescent immunometric assay technique (Siemens Immulite 2000 LH). Our results show that the administration of either methoxyisoflavone or ipriflavone causes an alteration of the urinary concentrations and concentration ratios of the investigated steroids, in the range 55-80% from the baseline values. Furthermore, an oversecretion of LH after the daily intake of methoxyisoflavone or ipriflavone was also recorded in all volunteers, corresponding to an increase in the biosynthesis and excretion of T and some of its metabolites. These changes trigger a disregulation in the pattern of urinary excretion of the steroids included in the Steroidal Module of the ABP, which makes more difficult the interpretation of the longitudinal steroid profile based on the definition of individual normality ranges for each athlete. Our data are also consistent with previous evidence regarding the in vitro effects of natural and synthetic isoflavones, suggesting that their monitoring in doping control routine analysis would be very beneficial for the result management activities.

Chinese Herbal Medicine Significantly Impacts the Haematological Variables of the Athlete Biological Passport

In the fight against sports doping, the Athlete Biological Passport (ABP) system aims to indirectly unveil the doping incidents by monitoring selected biomarkers; however, several unexplored extrinsic factors may dampen a fair interpretation of ABP profiles. Chinese herbal medicine (CHM) plays a pivotal role in the health care system, and some remedies have a long history of being used to treat anaemia. In this study, we addressed the concerns of whether the CHM administration could yield a measurable effect on altering the ABP haematological variables. Forty-eight healthy volunteers were randomly assigned to receive two-week oral administration of one of the six selected CHM products that are commonly prescribed in Taiwan (eight subjects per group). Their blood variables were determined longitudinally in the phases of baseline, intervention, and recovery over 5 weeks. Blood collection and analyses were carried out in strict compliance with relevant operating guidelines. In the groups receiving Angelicae Sinensis Radix, Astragali Radix, and Salviae Miltiorrhizae Radix et Rhizoma, a significant increased reticulocyte percentage and decreased OFF-hr Score were manifested during the intervention, and such effects even sustained for a period of time after withdrawal. All other variables, including haemoglobin and Abnormal Blood Profile Score, did not generate statistical significance. Our results show that the use of CHM may impact the ABP haematological variables. As a consequence, we recommend athletes, particularly those who have been registered in the testing pool, should be aware of taking specific Chinese herbal-based treatment or supplementation, and document any of its usage on the anti-doping forms.

Metabolomic signatures in elite cyclists: differential characterization of a seeming normal endocrine status regarding three serum hormones

INTRODUCTION

Serum phenotyping of elite cyclists regarding cortisol, IGF1 and testosterone is a way to detect endocrine disruptions possibly explained by exercise overload, non-balanced diet or by doping. This latter disruption-driven approach is supported by fundamental physiology although without any evidence of any metabolic markers.

OBJECTIVES

Serum samples were distributed through Low, High or Normal endocrine classes according to hormone concentration. A ¹H NMR metabolomic study of 655 serum obtained in the context of the longitudinal medical follow-up of 253 subjects was performed to discriminate the three classes for every endocrine phenotype.

METHODS

An original processing algorithm was built which combined a partial-least squares-based orthogonal correction of metabolomic signals and a shrinkage discriminant analysis (SDA) to get satisfying classifications. An extended validation procedure was used to plan in larger size cohorts a minimal size to get a global prediction rate (GPR), i.e. the product of the three class prediction rates, higher than 99.9%.

RESULTS

Considering the 200 most SDA-informative variables, a sigmoidal fitting of the GPR gave estimates of a minimal sample size to 929, 2346 and 1408 for cortisol, IGF1 and testosterone, respectively. Analysis of outliers from cortisol and testosterone Normal classes outside the 97.5%-confidence limit of score prediction revealed possibly (i) an inadequate protein intake for outliers or (ii) an intake of dietary ergogenics, glycine or glutamine, which might explain the significant presence of heterogeneous metabolic profiles in a supposedly normal cyclists subgroup.

CONCLUSION

In a next validation metabolomics study of a so-sized cohort, anthropological, clinical and dietary metadata should be recorded in priority at the blood collection time to confirm these functional hypotheses.

Effects of the administration of miconazole by different routes on the biomarkers of the "steroidal module" of the Athlete Biological Passport

This article reports the results obtained from the investigation of the influence of miconazole administration on the physiological fluctuation of the markers of the steroid profile included in the “steroidal module” of the Athlete Biological Passport. Urines collected from male Caucasian subjects before, during, and after either systemic (i.e., oral and buccal) or topical (i.e., dermal) treatment with miconazole were analyzed according to validated procedures based on gas chromatography coupled to tandem mass spectrometry (GC–MS/MS) (to determine the markers of the steroid profile) or liquid chromatography coupled to MS/MS (LC–MS/MS) (to determine miconazole urinary levels). The results indicate that only after systemic administration, the markers of the steroid profile were significantly altered. After oral and buccal administration, we have registered (i) a significant increase of the 5α‐androstane‐3α,17β‐diol/5β‐androstane‐3α,17β‐diol ratio and (ii) a significant decrease of the concentration of androsterone, etiocholanolone, 5β‐androstane‐3α,17β‐diol, and 5α‐androstane‐3α,17β‐diol and of the androsterone/etiocholanolone, androsterone/testosterone, and 5α‐androstane‐3α,17β‐diol/epitestosterone ratios. Limited effects were instead measured after dermal intake. Indeed, the levels of miconazole after systemic administration were in the range of 0.1–12.5 μg/ml, whereas after dermal administration were below the limit of quantification (50 ng/ml). Significant alteration started to be registered at concentrations of miconazole higher than 0.5 μg/ml. These findings were primarily explained by the ability of miconazole in altering the kinetic/efficacy of deglucuronidation of the endogenous steroids by the enzyme β‐glucuronidase during the sample preparation process. The increase of both incubation time and amount of β‐glucuronidase was demonstrated to be effective countermeasures in the presence of miconazole to reduce the risk of uncorrected interpretation of the results.

The Specificities of Elite Female Athletes: A Multidisciplinary Approach

Female athletes have garnered considerable attention in the last few years as more and more women participate in sports events. However, despite the well-known repercussions of female sex hormones, few studies have investigated the specificities of elite female athletes. In this review, we present the current but still limited data on how normal menstrual phases, altered menstrual phases, and hormonal contraception affect both physical and cognitive performances in these elite athletes. To examine the implicated mechanisms, as well as the potential performances and health risks in this population, we then take a broader multidisciplinary approach and report on the causal/reciprocal relationships between hormonal status and mental and physical health in young (18-40 years) healthy females, both trained and untrained. We thus cover the research on both physiological and psychological variables, as well as on the Athlete Biological Passport used for anti-doping purposes. We consider the fairly frequent discrepancies and summarize the current knowledge in this new field of interest. Last, we conclude with some practical guidelines for eliciting improvements in physical and cognitive performance while minimizing the health risks for female athletes.

Measurement of Immature Reticulocytes in Dried Blood Spots by Mass Spectrometry

BACKGROUND

Immature reticulocytes (IRC) are the first cells to respond to changes in erythropoiesis. For antidoping applications, measurement of IRC may improve detection of blood doping practices. Unfortunately, this small cell population has limited stability in liquid blood samples and is difficult to measure with optimal precision. We developed a method to measure 3 IRC membrane proteins in dried blood spots (DBS) to monitor changes in erythropoiesis.

METHODS

DBS spots were washed with buffers to remove soluble proteins, membrane proteins remaining in the spot were digested with trypsin, and one peptide for each protein was measured by LC-MS/MS. IRC protein concentration was determined using a DBS single point calibrator.

RESULTS

Intraassay precision for IRC proteins was between 5%-15%. IRC proteins were stable in DBS for 29 days at room temperature. In a longitudinal study of 25 volunteers, the mean intraindividual variation for 3 IRC proteins was 17%, 20%, and 24% from capillary blood DBS. In comparison, the mean longitudinal variation for IRC counts measured on an automated hematology analyzer was 38%. IRC protein concentration from capillary blood DBS correlated well with venous blood DBS protein concentrations.

CONCLUSIONS

Measurement of IRC proteins in DBS samples provides a method to measure changes in erythropoiesis with improved analytical sensitivity, stability, and precision. When combined with the inherent advantages of capillary blood collection in the field, this method may substantially improve the detection of blood doping practices.

miRNAs detection in equine plasma by quantitative polymerase chain reaction for doping control: Assessment of blood sampling and study of eca-miR-144 as potential erythropoiesis stimulating agent biomarker

Short half-life doping substances are, quickly eliminated and therefore difficult to control with traditional analytical chemistry methods. Indirect methods targeting biomarkers constitute an alternative to extend detection time frames in doping control analyses. Gene expression analysis (i.e., transcriptomics) has already shown interesting results in both humans and equines for erythropoietin (EPO), growth hormone (GH), and anabolic androgenic steroid (AAS) misuses. In humans, circulating cell-free microRNAs in plasma were described as new potential biomarkers for control of major doping agent (MDA) abuses. The development of a quantitative polymerase chain reaction (qPCR) method allowing the detection of circulating miRNAs was carried out on equine plasma collected on different type of tubes (EDTA, lithium-heparin [LiHep]). Although analyzing plasma collected in EDTA tubes is a standard method in molecular biology, analyzing plasma collected in LiHep tubes is challenging, as heparin is a reverse transcription (RT) and a PCR inhibitor. Different strategies were considered, and attention was paid on both miRNAs extraction quality and detection sensitivity. The detection of endogenous circulating miRNAs was performed and compared between the different types of tubes. In parallel, homologs of human miRNAs characterized as potential biomarkers of doping were sought in equine databases. The miRNA eca-miR-144, described as potential erythropoiesis stimulating agents (ESAs) administration candidate biomarker was retained and assessed in equine post-administration samples. The results about the qPCR method development and optimization are exposed as well as the equine miRNAs detection. To our knowledge, this work is the first study and the proof of concept of circulating miRNAs detection in plasma dedicated to equine doping control.

The Influence of Training Load on Hematological Athlete Biological Passport Variables in Elite Cyclists

The hematological module of the Athlete Biological Passport (ABP) is used in elite sport for antidoping purposes. Its aim is to better target athletes for testing and to indirectly detect blood doping. The ABP allows to monitor hematological variations in athletes using selected primary blood biomarkers [hemoglobin concentration (Hb) and reticulocyte percentage (Ret%)] with an adaptive Bayesian model to set individual upper and lower limits. If values fall outside the individual limits, an athlete may be further targeted and ultimately sanctioned. Since (Hb) varies with plasma volume (PV) fluctuations, possibly caused by training load changes, we investigated the putative influence of acute and chronic training load changes on the ABP variables. Monthly blood samples were collected over one year in 10 male elite cyclists (25.6 ± 3.4 years, 181 ± 4 cm, 71.3 ± 4.9 kg, 6.7 ± 0.8 W^.kg^-1 5-min maximal power output) to calculate individual ABP profiles and monitor hematological variables. Total hemoglobin mass (Hbmass) and PV were additionally measured by carbon monoxide rebreathing. Acute and chronic training loads-respectively 5 and 42 days before sampling-were calculated considering duration and intensity (training stress score, TSS^TM). (Hb) averaged 14.2 ± 0.0 (mean ± SD) g^.dL^-1 (range: 13.3-15.5 g·dl^-1) over the study with significant changes over time (P = 0.004). Hbmass was 1030 ± 87 g (range: 842-1116 g) with no significant variations over time (P = 0.118), whereas PV was 4309 ± 350 mL (range: 3,688-4,751 mL) with a time-effect observed over the study time (P = 0.014). Higher acute-but not chronic-training loads were associated with significantly decreased (Hb) (P <0.001). Although individual hematological variations were observed, all ABP variables remained within the individually calculated limits. Our results support that acute training load variations significantly affect (Hb), likely due to short-term PV fluctuations, underlining the importance of considering training load when interpreting individual ABP variations for anti-doping purposes.

On the trail of blood doping-microRNA fingerprints to monitor autologous blood transfusions in vivo

Autologous blood doping refers to the illegal re-transfusion of any quantities of blood or blood components with blood donor and recipient being the same person. The re-transfusion of stored erythrocyte concentrates is particularly attractive to high-performance athletes as this practice improves their oxygen capacity excessively. However, there is still no reliable detection method available. Analyzing circulating microRNA profiles of human subjects that underwent monitored autologous blood transfusions seems to be a highly promising approach to develop novel biomarkers for autologous blood doping. In this exploratory study, we randomly divided 30 healthy males into two different treatment groups and one control group and sampled whole blood at several time points at baseline, after whole blood donation and after transfusion of erythrocyte concentrates. Hematological variables were recorded and analyzed following the adaptive model of the Athlete Biological Passport. microRNA profiles were examined by small RNA sequencing and comprehensive multivariate data analyses, revealing microRNA fingerprints that reflect the sampling time point and transfusion volume. Neither individual microRNAs nor a signature of transfusion-dependent microRNAs reached superior sensitivity at 100% specificity compared to the Athlete Biological Passport (≤11% 6 h after transfusion versus ≤44% 2 days after transfusion). However, the window of autologous blood doping detection was different. Due to the heterogenous nature of doping, with athletes frequently combining multiple medications in order to both gain a competitive advantage and interfere with known testing methods, the true applicability of the molecular signature remains to be validated in real anti-doping testings.

A comparison of methods to generate adaptive reference ranges in longitudinal monitoring

In a clinical setting, biomarkers are typically measured and evaluated as biological indicators of a physiological state. Population based reference ranges, known as 'static' or 'normal' reference ranges, are often used as a tool to classify a biomarker value for an individual as typical or atypical. However, these ranges may not be informative to a particular individual when considering changes in a biomarker over time since each observation is assessed in isolation and against the same reference limits. To allow early detection of unusual physiological changes, adaptation of static reference ranges is required that incorporates within-individual variability of biomarkers arising from longitudinal monitoring in addition to between-individual variability. To overcome this issue, methods for generating individualised reference ranges are proposed within a Bayesian framework which adapts successively whenever a new measurement is recorded for the individual. This new Bayesian approach also allows the within-individual variability to differ for each individual, compared to other less flexible approaches. However, the Bayesian approach usually comes with a high computational cost, especially for individuals with a large number of observations, that diminishes its applicability. This difficulty suggests that a computational approximation may be required. Thus, methods for generating individualised adaptive ranges by the use of a time-efficient approximate Expectation-Maximisation (EM) algorithm will be presented which relies only on a few sufficient statistics at the individual level.

Biological variation: Understanding why it is so important?

This Review will describe the increasing importance of the concepts of biological variation to clinical chemists. The idea of comparison to 'reference' is fundamental in measurement. For the biological measurands, that reference is the relevant patient population, a clinical decision point based on a trial or an individual patient's previous results. The idea of using biological variation to set quality goals was then realised for setting Quality Control (QC) and External Quality Assurance (EQA) limits. The current phase of BV integration into practice is using Patient-Based Real-Time Quality Control (PBRTQC) and Patient Based Quality Assurance (PBQA) to detect a change in assay performance. The challenge of personalised medicine is to determine an individual reference interval. The Athletes Biological Passport may provide the solution.

Inter-Laboratory Agreement of Insulin-like Growth Factor 1 Concentrations Measured Intact by Mass Spectrometry

BACKGROUND

Insulin-like growth factor-I (IGF-1) is measured mainly by immunoassay for the diagnosis and treatment of growth hormone (GH) disorders, and to detect misuse of GH in sport. Immunoassays often have insufficient inter-laboratory agreement, especially between commercial kits. Over the expected range of IGF-1 in blood (∼50-500 ng/mL), in an inter-laboratory study we previously established a measurement imprecision of 11% (%CV) for the digested protein analyzed by LC-MS. Measuring intact IGF-1 by LC-MS should be simpler. However, no inter-laboratory agreement has been published.

METHODS

Intact and trypsin-digested IGF-1 in 32 serum samples from healthy volunteers and human growth hormone administration studies were analyzed by LC-MS using different instruments in five laboratories, as well as by immunoassay in a single laboratory. Another 100 samples were analyzed for IGF-1, both intact and after trypsin-digestion, in each laboratory by LC-MS. The statistical relationship between measurements and the imprecision of each assay group was assessed.

RESULTS

An intra-laboratory variability of 2-4% CV was obtained. Inter-laboratory variability was greater at 14.5% CV. Orthogonal regression of intact versus trypsin-digestion methods (n = 646) gave a slope of 1.01 and intercept of 2.05 ng/mL.

CONCLUSIONS

LC-MS measurements of IGF-1 by intact and trypsin-digestion methods are not statistically different and each is similar to immunoassay. The two LC-MS approaches may be used interchangeably or together to eliminate concerns regarding an immunoassay IGF-1 measurement. Because intact and digested IGF-1 measurements generally agreed within 20% of each other, we propose this as a criterion of assay acceptability.

Association Between Implementation of the Athlete Biological Passport and Female Elite Runners' Performance

The purpose of this research was to evaluate the performances of female middle- and long-distance runners before and after the implementation of a new antidoping strategy (the Athlete Biological Passport [ABP]) in a country accused of systematic doping. A retrospective analysis of the results of Russian National Championships from 2008 to 2017 was performed. The 8 best female performances for the 800-m, 1500-m, 3000-m steeplechase, 5000-m, and 10,000-m events from the semifinals and finals were analyzed. The yearly number of athletes fulfilling standard qualifications for international competitions was also evaluated. Overall, numbers of athletes banned for doping in 2008-2017 were calculated. As a result, 4 events (800, 1500, 5000 [all P < .001], and 10,000 m [P < .01]) out of 5 showed statistically significant deterioration in the performances when comparing before and after the introduction of the ABP. The 3000-m steeplechase was the only event that did not show statistically significant change. The highest relative decrease in the number of runners who met standard qualification for international competition was for the 5000-m event (46%), followed by 1500-m (42%), 800-m (38%), 10,000-m (17%), and 3000-m steeplechase (1%). In conclusion, implementation of the ABP was followed by a significant reduction in the performance of female runners in a country accused of systematic doping. It can be reasonably speculated that more stringent antidoping testing, more specifically the introduction of the ABP, is a key reason for this reduction.

Models to estimate biological variation components and interpretation of serial results: strengths and limitations

Biological variation (BV) has multiple applications in a variety of fields of clinical laboratory. The use of BV in statistical modeling is twofold. On the one hand, some models are used for the generation of BV estimates (within- and between-subject variability). Other models are built based on BV in combination with other factors to establish ranges of normality that will help the clinician interpret serial results for the same subject. There are two types of statistical models for the calculation of BV estimates: A. Direct methods, prospective studies designed to calculate BV estimates; i. Classic model: developed by Harris and Fraser, revised by the Working Group on Biological Variation of the European Federation of Laboratory Medicine. ii. Mixed-effect models. iii. Bayesian model. B. Indirect methods, retrospective studies to derive BV estimates from large databases of results. Big data. Understanding the characteristics of these models is crucial as they determine their applicability in different settings and populations. Models for defining ranges that help in the interpretation of individual serial results include: A. Reference change value and B. Bayesian data network. In summary, this review provides an overview of the models used to define BV components and others for the follow-up of patients. These models should be exploited in the future to personalize and improve the information provided by the clinical laboratory and get the best of the resources available.

Modelos para estimar la variación biológica y la interpretación de resultados seriados: bondades y limitaciones

La variación biológica (VB) tiene múltiples aplicaciones en diversos campos del laboratorio clínico. Hay dos formas de relacionar el concepto de VB y los modelos estadísticos. Por un lado existen modelos para el cálculo de estimados de VB (intra e inter individual) y por otro, existen modelos que tienen en cuenta la VB y otros factores para la definición de rangos que ayudan a la interpretación de resultados seriados en un mismo individuo. Dentro de los modelos estadísticos dirigidos al cálculo de los estimados de VB existen dos tipos: A. Métodos directos. Estudios prospectivos, diseñados exclusivamente para el cálculo de estimados de VB: i. Modelo clásico: desarrollado por Harris y Fraser, revisado por EFLM-BVWG. ii. Modelos de efectos mixtos iii. Modelo bayesiano. B. Métodos indirectos. Estudios retrospectivos basados en extraer estimados de VB a partir de resultados que provienen de grandes bases de datos. Big-data. Ambos tipos presentan una serie de características que es importante conocer porque pueden condicionar su aplicabilidad en diferentes situaciones o poblaciones. Entre los modelos para definir rangos que ayudan a la interpretación de resultados seriados en un individuo encontramos: A. Valor de referencia del cambio (VRC). B. Red de datos bayesiana. En resumen, esta revisión pretende dar un enfoque general sobre los modelos para definir los componentes de VB así como otros para aplicarlos en el seguimiento de pacientes, que deberían ser explorados en el futuro para personalizar y mejorar la información aportada por el laboratorio clínico, aprovechando al máximo los recursos disponibles.

Hematological adaptations and detection of recombinant human erythropoietin combined with chronic hypoxia

This study evaluated whether recombinant human erythropoietin (rhEpo) treatment combined with chronic hypoxia provided an additive erythropoietic response and whether the athlete biological passport (ABP) sensitivity improved with hypoxia. Two interventions were completed, each containing 4 weeks baseline, 4 weeks exposure at sea level or 2,320 m of altitude, and 4 weeks follow-up. Participants were randomly assigned to 20 IU·kg bw^-1 rhEpo or placebo injections every second day for 3 weeks during the exposure period at sea level (rhEpo n = 25, placebo n = 9) or at altitude (rhEpo n = 12, placebo n = 27). Venous blood was analyzed weekly. Combining rhEpo and hypoxia induced larger changes compared with rhEpo or hypoxia alone for [Hb] (p < 0.001 and p > 0.05, respectively), reticulocyte percentage (p < 0.001), and OFF-hr score (p < 0.01 and p < 0.001, respectively). The most pronounced effect was observed for reticulocyte percentage with up to ~35% (p < 0.001) and ~45% (p < 0.001) higher levels compared with rhEpo or hypoxia only, respectively. The ABP sensitivity for the combined treatment was 54 and 35 percentage points higher for [Hb] (p < 0.05) and reticulocyte percentage (p < 0.05), respectively, but similar for OFF-hr score, compared with rhEpo at sea level. Across any time point, [Hb] and OFF-hr score combined identified 14 unique true-positive participants (56%) at sea level and 12 unique true-positive participants (100%) at altitude. However, a concurrent reduction in specificity existed at altitude. In conclusion, rhEpo treatment combined with hypoxic exposure provided an additive erythropoietic response compared with rhEpo or hypoxic exposure alone. Correspondingly, ABP was more sensitive to rhEpo at altitude than at sea level, but a compromised specificity existed with hypoxic exposure.

Integration of molecular profiles in a longitudinal wellness profiling cohort

An important aspect of precision medicine is to probe the stability in molecular profiles among healthy individuals over time. Here, we sample a longitudinal wellness cohort with 100 healthy individuals and analyze blood molecular profiles including proteomics, transcriptomics, lipidomics, metabolomics, autoantibodies and immune cell profiling, complemented with gut microbiota composition and routine clinical chemistry. Overall, our results show high variation between individuals across different molecular readouts, while the intra-individual baseline variation is low. The analyses show that each individual has a unique and stable plasma protein profile throughout the study period and that many individuals also show distinct profiles with regards to the other omics datasets, with strong underlying connections between the blood proteome and the clinical chemistry parameters. In conclusion, the results support an individual-based definition of health and show that comprehensive omics profiling in a longitudinal manner is a path forward for precision medicine.

An important aspect of precision medicine is to probe the stability in molecular profiles among healthy individuals over time. Here, the authors sample a longitudinal wellness cohort and analyse blood molecular profiles as well as gut microbiota composition.

Biomarkers of doping: uses, discovery and validation

A biomarker of doping indicates the biological response to the use of a prohibited substance or method. Uncovering novel biomarkers of doping is a key objective in order to improve antidoping outcomes such as the detection of doping and changing athlete behavior toward doping practices. While the antidoping field has been successful in validating novel metabolites of prohibited substances, there has been less success in developing new biomarkers of doping. Employing the most suitable study designs and analytical approaches is critical to successfully uncovering novel biomarkers of doping with a high potential for translation into routine analysis. Here we argue that the antidoping field is well positioned for biomarker discovery and outline considerations for the development of novel biomarkers of doping.