Mise au point d'un nouvel outil de dépistage de l'administration de l'hormone de croissance équine recombinante par approche métabolomique

L hormone de croissance est une molécule protéique à activité anabolisante dont les propriétés peuvent être mises à profit pour améliorer les performances sportives des chevaux de courses et accroître la rentabilité de production des animaux d élevage. Cependant, la législation est très stricte car l utilisation de cette molécule ou de sa forme recombinante est interdite par le code des courses et les directives européennes en vigueur. Malgré les progrès scientifiques spectaculaires réalisés ces dernières années, le dépistage de l administration de l hormone de croissance reste difficile en particulier les premiers jours suivant un traitement. Récemment, de nouvelles méthodes de détection et d identification visant à améliorer le contrôle de l emploi illicite de promoteurs de croissance se sont développées. Les travaux de thèse présentés dans ce manuscrit s inscrivent dans ce contexte. Une approche non ciblée, de type métabolomique a été développée afin de mettre en évidence des perturbations métaboliques urinaires et plasmatiques chez des chevaux traités à l hormone de croissance recombinante équine. Les résultats obtenus par LC-HRMS ont permis de montrer la faisabilité analytique, la pertinence et l intérêt de cette approche puisque des modèles descriptifs et prédictifs autorisant la discrimination entre des chevaux contrôles et traités à l hormone de croissance ont pu être établis et validés. Cette méthode est actuellement mis en oeuvre et testée au Laboratoire des courses Hippiques. Le développement de ces études métabolomiques en lien avec d autres techniques omiques telles que la transcriptomique, ou la protéomique laisse penser que ces nouvelles stratégies pourront permettre de franchir un cap très significatif dans la lutte du contrôle anti-dopage dans les prochaines années.The growth hormone is a peptidic molecule with anabolic activity potentially used to improve horse athletic efficiency and to increase the production profitability of farm animals. However, the legislation is very strict and the use of this molecule or its recombinant form is strictly forbidden by the races code and the European directives in force. Despite the numerous scientific progresses achieved recently, the control of growth administration remains difficult. New methods of detection and identification to improve the control of illegal use of growth promoters have recently been developed. The phD thesis work presented in this manuscript has been conducted in this context. An untargeted approach based on metabolomic study was developed to highlight equine urinary and plasmatic metabolic disruptions induced by the administration of recombinant equine growth hormone. The results obtained by LC-HRMS have demonstrated the analytical feasibility, relevance and usefulness of this approach since descriptive and predictive models able to discriminate non-treated from growth hormone treated horses have been established and validated. This method is currently being assessed in the French laboratory of horse racing. The development of such new metabolomic studies in conjunction with other omic techniques such as transcriptomic or proteomic suggests that these new strategies could improve the anti-doping control in the futureNANTES-BU Sciences (441092104) / SudocSudocFranceF

Generation and processing of urinary and plasmatic metabolomic fingerprints to reveal an illegal administration of recombinant equine growth hormone from LC-HRMS measurements

Growth hormones are proteins produced by the anterior pituitary gland responsible for bone and tissue growth through their effects on carbohydrates, lipids and proteins metabolisms. Despite strict regulations banning the use of recombinant equine growth hormone, this substance is suspected to be misused to improve the horse physical performances. In order to check whether the regulation is fulfilled or not, controls are organized and a new analytical screening tool potentially able to detect such abuse was investigated in this paper. An untargeted metabolomics approach, based on liquid chromatography coupled to high resolution mass spectrometry, was developed and applied to characterize and compare horse urinary and plasmatic metabolic profiles upon reGH administrations. After minimal sample preparation, biological fluids were analyzed by LC-ESI(+/-)-Q-TOF. Data processing was performed by XCMS software and multivariate data analysis applied to the generated data set allowed building OPLS models to discriminate control versus treated populations. Results demonstrated significant metabolic modifications consecutively to the reGH treatment. A comparative study between urinary and plasmatic signatures was performed to evaluate the resulting metabolomic models and to asses their respective interests in the scope of real application for screening reGH administration

Lutte contre le dopage, des méthodes toujours plus performantes

Présentation des méthodes de dépistage du Laboratoire des Courses Hippiques (LCH)

Metabolomics in food analysis: application to the control of forbidden substances

International audienceMetabolomics is a science of interest in food analysis to describe and predict properties of food products and processes. It includes the development of analytical methods with the ultimate goal being the identification of so-called quality markers, (i.e. sets of metabolites that correlate with, for example, quality, safety, taste, or fragrance of foodstuffs). In turn, these metabolites are influenced by factors as genetic differences of the raw food ingredients (such as animal breed or crop species differences), growth conditions (such as climate, irrigation strategy, or feeding) or production conditions (such as temperature, acidity, or pressure). In cases where the routine-based measurement of a food property faces some limitations such as the lack of knowledge regarding the target compounds to monitor, monitoring based on a limited set of crucial biomarkers is a good alternative, which is of great interest for food safety purposes regarding growth promoting practices. Such an approach may be more efficient than using a classic approach based on a limited set of known metabolites of anabolic compounds. In this context, screening strategies allowing detection of the physiological response resulting from anabolic compound administration are promising approaches to detect their misuse. The global metabolomics workflow implemented for such studies is presented and illustrated through various examples of biological matrices profiling (tissue, blood, urine) and for different classes of anabolic compounds (steroids, beta-agonists and somatotropin). (c) 2012 John Wiley & Sons, Ltd