Projets de recherche

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Résumé
Cette recherche se propose d’étudier la manière dont les adolescents sportifs engagés dans une pratique du sport intensif font l’expérience de la douleur. Il s’agit de décrire la manière dont la douleur physique et morale est définie, évaluée, légitimée et parfois valorisée dans le sport. L’adolescent sportif, dont les insertions sociales sont encore fragiles et l’avenir incertain, doit apprendre à vivre avec et parfois en dépit de la douleur dans un contexte où le dépassement de soi, de ses limites, est très souvent présenté comme une condition de la réussite. Dans cette perspective, ce projet vise à identifier comment la douleur – parfois chronique - fait l’objet de pratiques de soins dans plusieurs sphères sociales. Le rapport à la douleur, sa prise en charge et la manière de prendre soin de l’adolescent sportif, de son hygiène de vie, n’est pas seulement le fait de la médecine du sport et de son expertise : la famille, l’entourage sportif ou un certain nombre de praticiens médicaux participent, eux aussi, à la gestion parfois négociée de la douleur et à la redéfinition continue des rapports entre le sport et la santé. Il est fait l’hypothèse que c’est dans le rapport à la douleur et non dans le rapport à la performance que pourrait se comprendre le dopage. En effet, nous pensons que les pratiques de dopage et les conduites addictives peuvent trouver leurs origines dans les pratiques de soin et la gestion chronique de la douleur physique et morale ressentie par les athlètes. 

Méthodologie

Transversale (méthodes mixtes - entretiens, questionnaire d'enquête).

Cette recherche se basera sur des entretiens semi-directifs (20) avec des jeunes sportifs et sur un questionnaire anonyme et auto-administré auprès de jeunes sportifs (300 adolescents majoritairement âgés de 12 à 17 ans) dont l’activité sportive les amène à venir deux fois par an faire un bilan sanitaire complet dans un service de médecine du sport d’un hôpital public. Par ailleurs et simultanément, l’administration du questionnaire auto-administré auprès de 300 autres jeunes athlètes, aux profils sociodémographiques similaires, mais fréquentant un autre site hospitalier et une autre antenne médicale permettra d’élargir et de renforcer l’étude. 

Résultats

L'expérience de la douleur chronique chez les athlètes peut conduire à une forte utilisation de "produits pharmaceutiques légaux" qui peuvent être négligés comme un risque, conduisant au dopage.

Le marché des médicaments analgésiques a tendance à croiser celui des produits dopants, de sorte que les deux ont parfois des frontières floues.

La consommation de médicaments peut constituer une sorte de dopage légal.  L'augmentation préoccupante de la consommation d'analgésiques chez les adolescents pourrait exposer ces jeunes à un risque plus élevé d'abus d'opiacés et constituer une sorte de pratique pré-dopage. 

Publications connexes

Le sport dans la douleur: de l'automédication au Mental training

La consommation d'antalgiques chez les adolescents sportifs : une étude exploratoire

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Code: 12C5YP

a) The use of recombinant human erythropoietin (r-HuEpo) is prohibited by the World Anti-Doping Agency. The purpose of a research project funded by WADA in 2008 entitled “A gene-microarray based approach to the detection of recombination human erythropoietin doping in endurance athletes” was to develop new methods with improved discriminatory power relative to current detection protocols based on gene expression profiles. On the basis of the preliminary data generated by this project, blood gene expression profiles were significantly altered during r- HuEpo administration and for at least 2 weeks after the r-HuEpo administration. These preliminary data are very promising, however, it is well known that athletes are now microdosing with r-HuEpo to minimise the risk of being caught via current detection methods. Therefore, in this project, we will compare blood gene expression profiles altered using a fairly high regimen of r-HuEpo injections of 50 IU/kg body mass every two days for 4 weeks (the previously funded project) with a microdose regimen (< 40 IU/kg body mass twice a week). Blood gene expression profiles following r-HuEpo administration will be assessed using gene-microarray technology. These results will be used to develop more specific and robust blood testing models applicable to the detection of microdose r-HuEpo doping.

b) Our research consortium has previously been funded by WADA as follows: In 2008 “A gene microarray based approach to the detection of recombinant human erythropoietin doping in endurance athletes” and a related project funded in 2010 “Application of a minimally-invasive method for RNA sampling and the addition of miRNA to the detection of recombinant human erythropoietin (r-HuEpo) use by athletes”. These recently funded projects were designed to provide the basis for the development of new detection methods with improved discriminatory capacity relative to current detection protocols using a “system biology” (i.e. gene expression and miRNA profiles assessed by the very latest gene-microarray technology) approach. Current progress with these WADA-funded projects is very encouraging and this success serves to reinforce the feasibility and need for this complex, expensive and technically demanding “systems biology” approach. Here we propose the addition of metabolomics (high resolution mass spectrometry methods) to the established research study aimed at identifying new metabolomic biomarkers that can differentiate between r-HuEpo administration and chronic altitude exposure (using samples already collected from WADA-funded studies). It is envisaged that this vital addition will help formulate new methods with improved discriminatory power relative to current detection protocols and in doing so eliminate the possibility of false-positives due to athletes living and/or training at altitude and false-negatives due to inadequate detection.

Main findings

a) Administration of recombinant human erythropoietin (rHuEpo) improves performance and hence is frequently subject to abuse by athletes. A limited detection window, a lack of sufficiently high sensitivity and specificity limit current testing. Previous WADA-funded research aimed at detecting high doses of rHuEpo doping using gene-based methods has generated promising results. The primary focus of this research is to apply this gene-based approach to the detection of microdoses of rHuEpo. The secondary aim of this research is to assess the performance effects of rHuEpo microdosing. Fourteen healthy endurance trained subjects not involved in competition during the study period participated in a 7 week randomised, double-blind, placebo-controlled crossover microdose rHuEpo regimen previously shown to increase haemoglobin mass. Maximum aerobic capacity and repeated sprint ability was assessed at baseline and during the week after the last rHuEpo/placebo injection. 18 genes were differentially expressed ten days after the first microdoses of rHuEpo. Of these 18 genes, 11 were consistently over-expressed during rHuEpo microdosing and under-expressed post administration thereby further validating the previously identified gene expression signature of rHuEpo. While no clear improvements in measures of anaerobic performance were observed following microdoses of rHuEpo, maximal aerobic capacity was significantly increased pre to post microdose rHuEpo administration by an average of 3.9%. In summary, this research provides strong evidence supporting the idea that gene-based biomarkers have real potential to improve the performance of current anti-doping methods such as the ABP for the detection of doping, not confined only to rHuEpo. In addition, this research highlights the need to improve current detection methods as rHuEpo microdosing has significant performance benefits.

b) Recombinant human erythropoietin (rHuEpo) is prohibited by the World Anti-Doping Agency but rHuEpo remains the drug of choice for many cheating athletes wishing to evade detection using current methods. Currently, the only validated direct test for rHuEpo is isoelectric focusing, but this test is severely limited by the short detection window of approximately 36-48 hours. Recent research funded by WADA has generated exciting new transcriptomics (i.e. gene expression) data to support the proof-of-concept idea of “omics” biomarkers as the preferred next generation anti-doping approach. Metabolomics (a key “omics” technology with widespread application in biomedicine) may further enhance this potential by providing a “snapshot” of the biological state of the organism/cell. The aim of this project was to identify a robust metabolomics signature of rHuEpo using an untargeted approach in blood (plasma and serum) and urine. Plasma, serum and urine samples were analyzed using the hydrophilic interaction liquid chromatography-mass spectrometry in 20 Caucasian males following 4 weeks of rHuEpo administration (i.e. 50 IU∙kg-1 body mass every two days). Three blood (plasma and serum) metabolites associated with red blood cells were identified as potential markers for rHuEpo detection. Although the diagnostic value of the identified metabolites for current rHuEpo detection methods is low, a combination of replicated metabolomic markers will provide a more detailed and thorough understanding of the perturbed system-s, thereby aiding ABP experts identify and differentiate numerous doping substances and methods when reviewing athlete biological passports. The present findings should encourage further metabolomics studies and the integrated reviewing of all “omics” data generated by other WADA anti-doping studies in order to aid the development of new detection models.

Code: 12C4MT

 Metabolomics has become a major tool in systems biology and biomarker discovery studies and possesses great potential also concerning modern anti-doping efforts. Most assays currently applied in doping controls are designed to sensitively and specifically detect the administered drug or its diagnostic metabolite to provide unambiguous evidence for the presence of a banned substance. A few marker-based methods have also been established in the doping control arena such as the steroid profile and the hematological module of the Athlete Biological Passport. 
The influence of ‘external circumstances’ on the metabolome has been recognized decades ago, particularly concerning the diagnosis of diseases. Analogously, the search for biomarkers towards the detection of drug (ab)use in sport will be of great utility for a modern anti-doping fight as demonstrated in pilot studies concerning animal sport and livestock production. Upon drug administration, shifts in metabolomic signatures occur; these are largely unknown but, once identified, potentially easier and/or longer monitored than the administered compound(s). Hence, analysis, quantitation, or profiling of (bio)markers rather than the detection of the drug itself will indicate and possibly provide evidence for a previous illicit intervention on the basis e.g. of growth promoting hormones. This is especially helpful for those therapeutics and designer substances that are difficult to determine (due to short half-life or structures identical with endogenously produced hormones). Modern analytical tools, particularly mass spectrometry-based methods, have proved useful for the identification of parameters that provide information on metabolome alterations. In combination with biostatistics, multivariate statistical analyses are enabled to highlight the value of identified compounds as potential (bio)markers. Upon characterization of marker candidates, these analytes can be implemented in anti-doping methods. Therefore, a comprehensive screening of the urinary metabolome of samples collected from different (administration) studies is planned to provide new insights into new targets for future doping control programs. 

Main Findings:

The urinary metabolome, i.e the entire set of low molecular mass substances of the human organism eliminated into urine, is composed of the endogenous and the exogenous metabolome. This reflects the metabolic products naturally produced by the individual and metabolites resulting from xenobiotics (e.g. drugs, toxins, food additives, etc.), respectively. It is consequently an extraordinary complex and dynamic object, which is significantly influenced (amongst others) by drug (mis)use. In order to assess whether –omics strategies such as urine metabolomics can indicate the misuse of drugs relevant in a doping control context, a pilot study was conducted, probing for the potential of this analytical strategy of identifying samples collected during and after applications of anabolic-androgenic steroids. Three scenarios were pursued with controlled administration studies including (1) oral, and (2) transdermal testosterone, where both intra- and interindividual variations of the metabolome were measured. In addition, the metabolome of a reference population of healthy and active individuals was compared to the urinary metabolome of athletes tested positive for the misuse of anabolic-androgenic steroids in routine doping controls (3). The urinary metabolomic ‘signatures’ were recorded using high resolution/high accuracy mass spectrometry with both gas chromatographic and liquid Chromatographic separation of analytes to provite utmost comprehensiveness. Followwing smaples analyses, non-targeted data evaluation was conducted to enable pattern recognition as supported by statistical methods such as principal component analysis (PCA) and orthogonal projection to latent structures (OPLS). 
Comparing the samples of the reference population with those resulting from adverse analytical findings (i.e. scenario 3), extreme interindividual variations were observed. Nevertheless, distribution patterns of typical non-suspicious and atypical urine samples were also recognized that potentially contribute information supporting the identification of unusual anti-doping analyses. Within both testosterone administration studies (1 and 2) it was readily possible to distinguish between pre- and post-administration samples on an individual basis. By comparing the undisturbed metabolome of each volunteer with the effects induced by testosterone, many entities or metabolites could be detected that were either up- or down-regulated. Even for the application of low doses of testosterone via transdermal testosterone gel, the metabolome was significantly influenced in all 4 volunteers on an individual basis. However, the interindividual variability was extensive and the effects of testosterone administrations on the metabolome became more or less negligible compared to the large biological differences. These individual variations are composed of many factors such as the different regulation of enzymes and metabolic pathways due to physical activity or simply the individual´s diet. Consequently, metabolome analyses seem to have potential to indicate drug (mis)use based on pattern positioning when compared to a reference population. Moreover, supporting information on anabolic-androgenic steroid misuse (here: testosterone) is obtained when intraindividual metabolomics data are available.  
On a sideline, another unexpected result was observed. The UDP-glucuronosyltransferase 2B17 genotype obviously has a large impact not only on selected glucuronidated (steroid) metabolites but seems to significantly influence the entire urinary metabolome. Since only 2 participants with this polymorphism were included in this study it remains speculative if identifying the genotype can be accomplished by a distinctive urinary metabolome pattern; however, the preliminary dataset suggests this possibility.

Code: 12A2MT

Within the last few years a new class of substances emerged in the focus of sports drug testing, so called gene doping agents. One of these called AICAR (aminoimidazolecarboxyamide-ribonucleoside) has proved to enhance physical performance, even without training, in animal experiments. 
In the course of clinical trials AICAR has been administered to human beings to investigate its health care properties related to type-2 diabetes. As during these studies no major side effects were reported it cannot be excluded that AICAR will be of interest for cheating athletes.  Therefore, the World Anti-Doping Agency included AICAR on their list of prohibited substances in 2009 and doping control laboratories started to establish methods for detecting AICAR-abuse. Until now, urinary concentrations of AICAR have been determined and reference-based thresholds were suggested due to the fact that AICAR is an endogenously produced substance and occurs in every urine specimen. As the observed biological variability in urinary concentration was high – as also reported for other classes of substances such as steroids – these thresholds are quite high and endogenously produced AICAR can potentially be found beyond the reference limit in rare cases. In analogy to steroids, the carbon isotope ratio determination would be the method of choice to distinguish endogenous from exogenous/administered AICAR. Hence, the aims of this study are to develop and validate a method for the determination of carbon isotope ratio values of AICAR and to elucidate the endogenous 13C/12C ratios of this compound. Additionally, the 13C/12C ratios of synthesized AICAR will be determined to enable the calculation of a clear cut-off criterion between the endogenous and the exogenous AICAR. 

Main Findings: 

AICAR (5-Aminoimidazole-4-carboxamide 1β-D-ribofuranoside) is prohibited in sport according to rules established by the World Anti-Doping Agency. Doping control laboratories identify samples suspicious of AICAR abuse by measuring its urinary concentration and comparing the observed level to naturally occurring concentrations. As the inter-individual variance of urinary AICAR concentrations is large, this approach requires a complementary method to unambiguously prove the exogenous origin of AICAR. Therefore a method for the determination of carbon isotope ratios (CIR) of urinary AICAR has been developed and validated. Concentrated urine samples were fractionated by means of liquid chromatography for analyte clean up. Derivatization of AICAR yielding the trimethylsilylated analog was necessary to enable CIR determinations by gas chromatography-combustion-isotope ratio mass spectrometry. The method was tested for its repeatability and stability over time and a linear mixing model was applied to test for possible isotopic discrimination. A reference population of n = 63 males and females was investigated to calculate appropriate reference limits to differentiate endogenous from exogenous urinary AICAR. These limits were tested by an AICAR elimination study.    
The developed method fulfils all requirements for adequate sports drug testing and was found to be fit for purpose. The investigated reference population showed a larger variability in CIR of AICAR as for endogenous steroids. Nevertheless, the calculated thresholds for differences between AICAR and endogenous steroids can be applied straightforward to evaluate suspicious doping control samples with the same statistical confidence as established e.g. for testosterone misuse. These thresholds enabled the detection of a single oral AICAR administration for more than 40 h.  
Determination of CIR is the method of choice to distinguish between an endogenous or exogenous source of urinary AICAR. The developed method will enable investigations into doping control samples with elevated urinary concentrations of AICAR and clearly differentiate between naturally produced/elevated and illicitly administered AICAR.