Projets de recherche

Code: 15A21MP 

As per list of the World Anti-Doping Agency (WADA) 2015 Oral-Turinabol (4-chloro-17β-hydroxy-17α-methylandrosta-1,4-dien-3-one), which was extensively misused by GDR athletes is prohibited in sports. In recent years it has been rediscovered by producers of "dietary supplements" and gained new importance in doping control (continuously increasing numbers of adverse analytical findings since 2003). Following its administration long-term metabolites with 4-chloro-17β-hydroxymethyl-17α-methyl-18-norandrost-13-ene structure have been identified. However these metabolites are not available as reference substance up to now. Even though the use of post-administration urines instead of purified reference material has been accepted in confirmatory analyses, the athletes in question may challenge the results of the anti-doping laboratories resulting in prolonged trials. The goal of the present project is to produce Oral-Turinabol long-term metabolites with 4-chloro-17β-hydroxymethyl-17α-methyl-18-norandrost-13-ene structure that cannot be synthesised via classical chemical synthesis. Therefore a joint chemical synthesis and biotechnological approach will be applied. The substrate (17,17-dimethyl-18-nor-13-ene intermediate) will be converted by single-step hydroxylation to the desired product in a whole-cell biotransformation assay using recombinant strains of fission yeasts that express the human cytochrome P450 enzymes CYP 3A4 or CYP 21 as already successfully performed for the analogue metandienone long-term metabolite by our group, that is now available in worldwide anti-doping laboratories. As already published by our group both enzymes catalyze the respective reaction in Oral-Turinabol as well. Prior to the biotechnological hydroxylation, the substrate will be chemically derived from Oral-Turinabol by Wagner-Weerwein rearrangement. Purification and subsequent NMR structure confirmation will be performed and the product distributed to the anti-doping community. 

Main Findings: 

Anabolic androgenic steroids (AAS) are misused very frequently in sport competitions as performance enhancing agents. One of the doping compounds that has been detected with increased frequency in the last few years is dehydrochloromethyltestosterone (DHCMT, 4-chloro-17β-hydroxy-17α-methylandrosta-1,4-dien-3-one; brand name Oral Turinabol). Since the parent drug DHCMT (10) is eliminated relatively fast from the human body, efforts to detect its illicit use have concentrated on its metabolites for many years. In recent years, some metabolites with 17β-hydroxymethyl-17α-methyl-18-norandrost-13-ene structure were detected as metabolites following the administration of different 17α-methyl steroids. 
The long-term DHCMT metabolites 20βOH-NorDHCMT (4-chloro-17β-hydroxymethyl-17α-methyl-18-norandrosta-1,4,13-trien-3-one) and its A-ring reduced analogue 20βOH-NorTHCMT (4ξ-chloro-17β-hydroxymethyl-17α-methyl-18-nor-5ξ-androst-13-ene-3ξ-ol) were reported earlier, however without providing reference material and assigning the stereochemistry of the latter. Very recently the stereochemistry of the latter was reported as 3α,4α,5α.

In this study we investigated the applicability of a combined chemical and biotechnological approach for the synthesis of reference material. A combination of Wagner-Meerwein rearrangement of DHCMT to NorDHCMT (4-chloro-17,17-dimethyl-18-norandrosta-1,4,13-trien-3-one) and subsequent whole-cell biotransformation with a recombinant fission yeast strain expressing human cytochrome P450 enzymes subtype 21A2 (CYP21A2) was successfully used for the synthesis of mg amounts of 20βOH-NorDHCMT.

Unexpectedly, this approach failed in the synthesis of 20βOH-NorTHCMT. It was observed that substrates with 3-hydroxy groups are neither hydroxylated on C20 by CYP21A2 nor by CYP3A4. Further confirmation of this finding was obtained by testing other 17,17-dimethyl-18-norandrost-13-ene steroids. Thus, insights into the structure-activity relationship of these enzymes were provided.

Furthermore, post administration urines of DHCMT were analyzed for the presence of 20βOH-Nor-metabolites. Both metabolites, 20βOH-NorDHCMT and 20βOH-NorTHCMT, were detected in very low abundances in the urines.

Code: 15C01DS 

Tramadol is an analgesic medication for the treatment of moderate to severe pain. Recently, there have been concerns about the abuse of tramadol causing falls in the pro-cycling peloton. Only few studies have examined the effects of Tramadol on performance and none with athletes or healthy subjects. The impact of Tramadol on cycling performance might be mediated by its effect on sustained attention, which is defined as a capacity to detect of relevant stimuli that are rare and unpredictable. 
The aims of this project are: 1) to investigate the impact of Tramadol on physical performance in cycling with a Functional threshold power test (1st year); 2) to investigate the effect of Tramadol on sustained attention at rest (1st year) and during exercise (2nd year) with the Continuous Performance Task; 3) to study whether sustained attention might mediate the effect of Tramadol on cycling performance with an ecologically-valid task (3rd year). All experiments to reach the objectives will be performed using a placebo-controlled, double blind, randomized counterbalance methodology. Tramadol (a single dose of 100 mg of orally administered will be used) or Placebo will be administered to participants 120 min before starting each test. We will recruit 30 subjects for each experiment (15 males and 15 females). Together with objective measures of physical and cognitive performance, we will obtain measures of subjective performance such as perceived effort and mental fatigue. 
This research project will be the first to test the effects of Tramadol on sustained attention during cycling. This is particularly relevant since Tramadol has been placed on WADA’s Monitoring Program from 2012 to 2015 (Narcotics: in competition only) in order to detect potential patterns of abuse. Our findings would certainly help the WADA to decide whether to include Tramadol into the Prohibited List or not. 

Main Findings: 

The use of tramadol, an analgesic medication, in professional cycling is generating particular interest and concern. Tramadol might enhance cycling performance at the cost of reducing the ability to stay focused. The aim of the present study was to test the hypothesis that acute oral administration of tramadol improves exercise performance during a 20-min cycling Time-Trial (TT) (Experiment 1) in a group of cyclists and whether sustained attention would be impaired during exercise (Experiment 2).

This study is a clinical trial (EudraCT number: 2015-005056-96) using a placebo-controlled, double blind, within-participants, counterbalanced methodology.  We administered a single oral dose of Tramadol (100 mg), or placebo 120min before starting the TT. Electroencephalography measures (EEG) were recorded throughout the cycling exercise and at rest. In Experiment 2, the methods were the same as in Experiment 1 except that participants performed an Oddball (cognitive) sustained attention task during exercise.

We recruited 56 cyclists in total. In Experiment 1, overall power output was higher in the tramadol condition than in the placebo condition. This result was partially replicated in Experiment 2, as the power output during the second half of the TT was higher under tramadol, while no differences were observed in the first part of the TT. No effects of condition were shown either in the PVT or the oddball task.  Tonic EEG analysis at baseline revealed opposite results when comparing Experiments 1 and 2. However, EEG data showed a significant effect at the neural-related activity related to stimulus processing during exercise.

Futures studies should include a pre-fatigue protocol at a fixed load before the TT to address this issue, and in addition a more ecological task.

Code: ISF15D03MG 

Autologous blood doping is applied in order to increase red blood cell (RBC) mass and thus oxygen transport capacity of the blood and to improve exercise performance.The International Olympic Committee (IOC) banned blood boosting after the 1984 Olympics and indirect markers for blood doping, including total haemoglobin mass measurements, or to test for the excretion of metabolites of bag plasticizers in the urine have been developed. 
The Athlete Biological Passport was introduced a couple of years ago and consists of a longitudinal monitoring of biologic measures to identify patterns suspicious of doping and evaluation of such abnormal patterns by a panel of experts. Parameters included are the hemoglobin concentration and the reticulocyte percentage but the latest incidents (e.g. doping charge Claudia Pechstein) proved that the interpretation of hematological parameters are difficult because of wide inter-individual differences. Thus, at present no reliable method exists to detect autologous blood doping. We have previously investigated how blood storage affects RBC deformability, which is an indispensable characteristic of RBC to ensure the oxygen supply to the tissues, and found that during hypothermic storage of liquid blood units RBC deformability decreases with increasing storage duration. This was associated with cell senescence and reduced nitric oxide bioavailability. Nowadays blood bags are cryopreserved for later re-infusion and thus the aim of the study is to investigate the impacts of cryopreservation on RBC deformability and associated nitric oxide signaling pathways. We hypothesize an impact of cryopreservation on these parameters. Thus, the investigation of RBC function and related cellular pathways seems to be a promising attempt in order to detect autologous blood doping.

Main Findings: 

Structure and function of red blood cells (RBC) may be affected during cryopreservation (freezing, storage, thawing of RBC) and identification of respective cell markers might aid to hint towards reinfusion of stored blood. In vitro and in vivo tests with cryopreserved RBC were conducted to investigate the effects of cryopreservation on parameters of RBC aging, integrity, (nitric oxide) metabolism, deformation and viscosity. Results revealed that cryopreservation does not affect basal blood parameters or cell metabolism but reduces cell aging which was reported to be a major problem in liquid preserved blood samples stored at 4°C. Overall ability of RBC to deform was reduced after cryopreservation but sensitivity to shear stress was
increased which might be related to remaining freezing medium in the cells that might affect the membranous structure of the RBC. Cryopreservation also alters osmotic stability of RBC further indicating that the membrane and/or the membrane-cytoskeleton interaction is affected by cryopreservation. Finally, viscosity of RBC was reduced which again, hints towards an effect of freezing medium on the viscoelastic properties of RBC. Nitric oxide metabolism, which accounts – at least in part –for RBC deformation process, was not affected by cryopreservation.

Reported effects were less measurable in vivo compared to in vitro suggesting that blood volume that was reinfused to respective donors in vivo was too little to detect any measurable changes in the tested parameters and which might not precisely reflect doping praxis. In conclusion, the data of the present study were the first to investigate changes of cryopreservation on RBC structure and function in more detail. Cryopreservation affects RBC structure leading to functional changes which needs further investigation to assess its effects in vivo.

Code: ISF15C15PV

Saliva is a well-established matrix in toxicology and clinic testing. However, for doping control purposes, it was shown that saliva analysis has very interesting pharmacokinetic properties after application of small doses of testosterone gel. Salivary testosterone concentrations exceeded normal values with a 100 fold and can provide good discriminating properties after low-dose application of testosterone. Currently, literature is short on salivary analysis for doping control purposes and data are absent on salivary concentrations and behavior of other androgen metabolites after intake of endogenous anabolic steroids. Consequently, this project aims to explore the possibility of steroid profiling in saliva and to relate its outcome with urinary analysis for future implementation in routine anti-doping screening. Consequently, a sensitive salivary steroid profiling method will be developed for the quantitative monitoring of testosterone and other androgen metabolites in the pg/ml-range. In a second stage, population thresholds for the monitored salivary compounds will be established in a cohort of 400 men and 400 women. Intra-individual variance shall be evaluated by analyzing longitudinal data of 10 male and 10 female volunteers. Within-subject variance on long term shall be evaluated in a period of six month with 10 oral fluid samples per volunteer. Intra-day variance shall be evaluated by collecting three aliquots per day during one week. Finally, it is planned to organize a series of administration studies with single doses of oral, gel and intra-muscular testosterone formulations and the intake of the prohormone dehydroepiandrosterone. The salivary steroid profile data will be compared with urinary steroid profiling data.

Main Findings

A quantitative method has been developed for the detection of 5 endogenous steroids (testosterone, androst-4-ene)-3,17-dione, dehydroepiandrosterone, cortisone and cortisol) in oral fluid. The method was validated and was capable of detecting accurately steroid concentrations in a reference population (387 males and 439 female volunteers). Based upon this reference population thresholds were established. In the future, these can be used to identify outliers. Intra-individual variation was investigated to evaluate the potential of saliva for a passport-like approach. Testosterone gel was administered to one volunteer and the changes in the salivary concentrations were evaluated. The concentration of T itself showed a dramatic increase, followed by a strong fluctuating pattern. For T-gel administration T itself and T/DHEA is provided the highest sensitivity/longest detection window. Hence, the method is suitable to detect misuse with synthetic analogues of natural steroids and shows a strong response to T use even in a formulation that is difficult to detect when using urine.

Code: 15A13CB 

The use of small peptides as growth hormones releasing factors has become increasingly popular in the last few years. As described in the literature, a whole set of small peptides emerged these last decades representing today a more and more attractive class of performance-enhancing drugs for amateur and professional athletes.  Several studies have reported the presence of these compounds in recent seized products confirming the illegal circulation of this class of substances. 
The best analytical tool to detect these small peptides and also their analogs or discover unknown similar compounds is the high resolution / high accuracy mass spectrometry (LC-HRMS). 
The aim of this study is to implement a high performance screening method by LC-HRMS in order to detect this new drug class. This project will focus on the available matrix from anti-doping tests: urine and blood (serum and plasma) but also on the seized products or internet-based drugs, which are the awareness keys of doping trends. Moreover, this project will also focus on the computer assisted method available with the LC-HRMS equipments. All the acquisition mode will be tested on the two technologies available in our laboratory (Q-Orbitrap and QqTOF) and an assessment of software helping to characterize metabolites without the reference material will be performed. The best strategy will be validated and applied to real samples from anti-doping controls.

Main Findings: 

A high performance screening procedure by LC-HRMS for prohibited peptides was developed and implemented in the laboratory. A protocol has been developed for urinary samples but also for plasma samples. Tests carried out show that the plasma method could also be easily applied to the serum samples. This screening protocol allows the detection of peptides < 2kDa but also peptides > 2kDa in a same method. The LOD obtained meet the WADA technical documents in force apart for larger peptides such as Tesamorelin, CJC-1295 or Sermorelin. For this category of peptides, another protocol should be applied in order to reach the expected LOD (0.5 ng/mL).  During this study, two kinds of instruments were evaluated: the QExactive+ system and the QTOF. The performances of the two instruments were globally equivalent but the QExactive+ instrument shows most of the time slightly better LODs and less background noise for some ion transitions. It was so retained as instrument of choice for drug testing routine analyses.  A stability study was performed during the validation process confirming that samples should be frozen as soon as possible after collection and stored frozen. A storage at +4°C is possible but should not exceed few days (3 days maximum for Alexamorelin or Goserelin for example).Seized products and internet-based compounds were also analyzed and characterized thanks to comparison with a database build on the instrument. On the twelve internet/seized products at our disposal, three of them showed incorrect identification on the original vial. For example, one vial identified as HGH frag 176-191 contains exclusively Sermorelin and another vial identified as TB-500 was in fact Thymosin 4. The last case was a vial identified as TB-1000 (supposed to be Thymosin 4) but it contains a mixture of TB-500 and its metabolite TB-500 M3.

Code: 15A15RV 

Current screening methods for exogenous anabolic androgenic steroids (AAS) are based on the hydrolysis of the urine samples using β-glucuronidase enzymes and the measurement of the released phase I metabolites using gas and liquid chromatography coupled to mass spectrometric techniques. In recent years, new long-term phase II metabolites of AAS, not detectable using the current screening conditions, have been identified using liquid chromatography-mass spectrometry technology, including glucuronoconjugated metabolites not readily hydrolysed with β-glucuronidase enzymes and sulfoconjugated metabolites. 
The hypothesis of the project is that significant information is missed in current AAS screening methods and the aim of the project is to develop a screening method based on the direct detection of the metabolites excreted in the urine, including phase II metabolites (glucuronides and sulfates) and relevant unconjugated metabolites using liquid chromatography coupled to tandem mass spectrometry with high resolution instruments. The method will improve the detection capabilities of AAS through the monitoring of important long-term metabolites, not detectable using the currently used screening methods. The approach will also facilitate the incorporation of new phase II metabolites. In addition, the possibility of acquiring full scan data will allow the retrospective reprocessing of all results for the detection of unknown metabolites, without the need of repeating the analysis. Moreover, the successful outcome of the project will represent a cost-effective simple approach, that can readily be shared amongst WADA accredited laboratories.

Main Findings: 

Current screening methods for exogenous anabolic androgenic steroids (AAS) are based on the hydrolysis of the urine samples using β-glucuronidase enzymes and the measurement of the released phase I metabolites using gas and liquid chromatography coupled to mass spectrometric techniques. In recent years, new long-term phase II metabolites of AAS, not detectable using the current screening conditions, have been identified using liquid chromatography-mass spectrometry technology, including glucuronoconjugated metabolites not readily hydrolysed with β-glucuronidase enzymes and sulfoconjugated metabolites.

The hypothesis of the project is that significant information is missed in current AAS screening methods and the aim of the project is to develop a screening method based on the direct detection of the metabolites excreted in the urine, including phase II metabolites (glucuronides and sulfates) and relevant unconjugated metabolites using liquid chromatography coupled to tandem mass spectrometry with high resolution instruments. The method will improve the detection capabilities of AAS through the monitoring of important long-term metabolites, not detectable using the currently used screening methods. The approach will also facilitate the incorporation of new phase II metabolites. In addition, the possibility of acquiring full scan data will allow the retrospective reprocessing of all results for the detection of unknown metabolites, without the need of repeating the analysis. Moreover, the successful outcome of the project will represent a cost-effective simple approach, that can readily be shared amongst WADA accredited laboratories.
         

Results and Conclusions:

Anabolic androgenic steroids (AAS) are the most frequently reported group of prohibited substances detected in doping controls. In recent years, new phase II metabolites of these compounds have been identified by LC-MS/MS and their usefulness improving the detection capabilities of the AAS misuse was demonstrated. However, the detection of some analytes was compromised due to the co-elution of endogenous interferences sharing the same ion transitions. The aim of this work was to evaluate the possibility of high-resolution mass spectrometry (HRMS), performed with LC-Q-TOF MS and LC-Q-Orbitrap MS systems, to overcome these limitations, thanks to the increased selectivity provided by the determination of the exact mass.  

The study of the ionization and fragmentation behaviour of unconjugated, sulfates and glucuronides steroids was performed with both Q-TOF and Q-Orbitrap instruments, acquiring fullscan and product ion spectra at different collision energies in positive and negative electrospray modes. The chromatographic conditions were optimized to achieve the best baseline separation of the isobaric compounds and to limit matrix interferences. The LC separation was finally performed with an Acquity UPLC BEH C18 column using H2O and CH3CN:H2O 95:5 (v/v) (0.01% formic acid, 1 mM ammonium formate) as mobile phase, with a total run time of 23 min. Solid-phase extraction (SPE) with Bond Elut C18 cartridges was used for sample clean-up and pre-concentration. Limits of detection (LODs), estimated with both HRMS systems, showed values below the 50% of the MRPL for sulfates and most of the glucuronides tested. Lower ionization efficiencies were obtained for some unconjugated steroids, producing unsatisfactory LODs with respect to WADA requirements.  

The Q-TOF-HRMS method was applied to urine samples obtained from oral and/or intramuscular administration of stanozolol, clostebol, methyltestosterone and metandienone, with the purpose to include in the study markers of these compounds that had been identified in previous works and for which standards were not available. Most of the main metabolites were identified on the basis of the accurate mass, relative retention time and characteristic fragmentation.  

Metabolomics strategies and statistical data analysis were used with the excretion studies after stanozolol and clostebol administrations to try to identify new metabolites. The most important metabolites already reported in the literature were identified using PLS-DA, but unfortunately, no new metabolites were discovered. Nevertheless, the results demonstrate the usefulness of the metabolomics strategy for the study of new metabolites. 
 
Overall, non-targeted screening methods based on HRMS instrumentation are a very useful tool in routine anti-doping analysis, with comparable applicability with respect to targeted MRM methods.

Code: 15A04JM 

The aim of the project is to produce a replacement freeze-dried human urine matrix certified reference material for the six steroids specified in the WADA technical document TD2014EAAS as markers for the urinary steroid profile. The material will be certified to a high level of accuracy with low uncertainties for the mass fraction and concentration of the steroid markers and testosterone to epitestosterone (T/E) ratio. The certified values will be assigned using isotope-dilution mass spectrometry and will be traceable to the International System of Units (SI). This material is intended to replace the stock of certified reference material NMIA MX005 which will be depleted over the next two years. MX005 has been used by WADA laboratories since its release in 2009 to demonstrate comparability of measurements now used for the Athlete Biological Passport (ABP). The ABP benefits all athletes by improving detection of doping and benefits individuals with unusual profiles by reducing unjustified scrutiny. The success of the ABP relies on results of
analysis for all samples from an individual athlete being comparable irrespective of the WADA laboratory that performed the analysis.  Comparability can be demonstrated by the appropriate use of a CRM specifically designed for the purpose.

Main Findings: 

A new freeze-dried human urine matrix certified reference material (CRM) has been produced to assist laboratories in longitudinal profiling measurements used for the Athlete Biological Passport and in the detection of testosterone abuse. Approximately 2400 units of the CRM (designated NMIA MX017) were produced and are now available to WADA accredited laboratories.  The material is provided with SI traceable reference values for the mass fractions and mass concentrations of the glucuronides of six steroids specified in the WADA technical document TD2018EAAS as markers for the urinary steroid profile: testosterone (T), epitestosterone (E), androsterone, etiocholanolone, 5α-androstane-3α,17β-diol and 5β-androstane-3α17β-diol. 

The CRM was produced using pooled urine from six healthy individuals that had been fortified with testosterone glucuronide to provide a T/E mass ratio of 4. The mass fractions and concentrations of the target steroid glucuronides in the reconstituted urine were determined using the primary ratio analytical method of exact matching double isotope dilution mass spectrometry (IDMS) following extensive sample clean-up. The analytical procedure developed and optimised for this CRM employed a heart-cutting two dimensional HPLC purification of the target analytes and quantification using five characteristic molecular fragments in tandem mass spectrometry or high resolution mass spectrometry coupled with two different GC columns.

Estimates of the uncertainty in the certified values are based on investigation into all sources of uncertainty in inputs to the measurement equation and on studies of the homogeneity and stability of the mass fractions of the six steroid metabolites in the freeze-dried urine material during long-term storage, transport and use. Mass fraction and concentration reference values in the Certificate of Analysis for the CRM have expanded uncertainties (at the 95% level of confidence) below 5%. This is the same or better than previous similar CRMs, ensuring that NMIA MX017 will be a suitable replacement in controlling the quality of longitudinal profiling data.

Code: ISF15A35PV 

Sewage based tracing of doping use by amateur athletes. The present project investigates the applicablilty of sewage analysis to assess doping use in the general population and for amateur athletes in particular. To this end an analytical chemical tool will be developed that can identify and quantify existing as well as new doping substances present in sewage and pooled urine. The project will assess uncertainties associated with the various steps of sewage based epidemiology: sampling, sewage treatment plant and sewer system design, excretion rates, substance stability (in sewer), population size. The methodology used will employ high resolution mass spectrometry that will allow identification of hitherto unknown doping substances, quantification of known substances, and retrospective searches for newly identified doping agents in samples earlier collected. The methodology developed will be tested in sewage from three major cities in The Netherlands and during a major amateur sport event.

Main Findings: 

The present study investigated the applicability of the chemical analysis of wastewater to assess the use of doping substances by the general population and amateur athletes. To this end, an analytical methodology that can identify and quantify a list of substances from the groups of anabolic steroids, weight-loss products and masking agents in wastewater has been developed. The method uses solid phase extraction to increase the detection sensitivity of the target analytes, expected to be present at very low concentrations (ng L-1 range), and decrease possible matrix interferences. Instrumental analysis is performed by liquid chromatography coupled to high-resolution mass spectrometry, allowing data acquisition in both full scan and tandem MS mode. The method has been successfully validated at two concentration levels (50 and 200 ng L-1) with limits of quantification ranging between 0.7 and 60 ng L-1, intra- and inter-day precision expressed as relative standard deviation below 15%, procedural recoveries between 60 and 160% and matrix effects ranging from 45 to 121%. The stability of the analytes in wastewater was evaluated at different storage temperatures illustrating the importance of freezing the samples immediately after collection. The application of the method to 24-h composite wastewater samples collected at the entrance of three wastewater treatment plants and one pumping station prior to, during, and immediately after different sport events revealed the presence in wastewater, and hence the use, of the weight-loss substances ephedrine, norephedrine, methylhexanamine and 2,4-dinitrophenol. In particular norephedrine and 2,4-dinitrophenol use appeared to coincide with the event., and in greater quantities than anabolic steroids. 

Code: 15A41CR 

The detection of the misuse of these peptides is challenging due to a rapid elimination and consequently low concentrations in body fluids. Despite the analytical challenge, screening procedures have already been established, targeting numerous GHRPs in urine, employing liquid chromatographic/mass spectrometric detection. Thus, the focus has mainly been on the detection of the parent compounds. The additional incorporation of metabolites in routine detection methods would improve detectability and furthermore increase the detection window of the peptides. For most of these compounds, no or only limited pharmacokinetic data are available on human excretion. Moreover, little is known about the toxicology of the non-approved compounds and human studies are challenged by ethical considerations. Nevertheless, animal in vivo studies, in addition to in vitro simulations of metabolic reactions, have identified metabolites which represent promising targets in doping control analysis. Unfortunately, the majority of these metabolites are not commercially available.
Thus, in the current project, we plan to synthesize six proposed human metabolites of different small peptide hormones, purify and structurally characterize them by high resolution high accuracy mass spectrometry (Orbitrap FT-MS/MS; e.g. Q Exactive). Furthermore, the synthesized metabolites will be incorporated in our peptide LC-MS/MS protocol in order to proof their detectability in a single run and together with their parent compounds as well as other prohibited small peptides. Since such peptide hormones are commonly administered in low doses and additionally show extensive metabolic degradation, well-characterized reference standards of targeted metabolites are of utmost importance for a sensitive and specific detection of this group of doping agents.

Main Findings: 

In this study, eight proposed peptide metabolites were successfully synthesized employing microwave peptide synthesis, including Fmoc-based peptide synthesis methods. Subsequently, the purified peptides were characterized by high-resolution high-accuracy mass spectrometry. The peptide structures were confirmed by the accurate peptide mass (mass error ± 0 ppm - 0.7 ppm), in addition to structural information from MS-MS analysis.

Metabolites synthesized : GHRP M1, M3, M4, M5, alexamorelin M1 to M3 and leuprolide M1

Code: 15A03GS

One of the strategies for the detection of growth hormone (GH) administration is the identification of abnormal ratios between the main GH proteoforms in blood circulation. However, the high sequence similarity between them complicates a precise differentiation when relying on antibody-based quantification.

For unambiguous and precise protein identification, we will use liquid chromatography - mass spectrometry (LC-MS) analysis for the quantification of the 22 and 20 kDa GH proteoforms. Before, we will develop a sample preparation strategy for blood samples based on a novel type of (hydrogel) nanoparticles, for sample simplification and reduction of the blood matrix complexity. These nanoparticles have shown the capacity to simultaneously deplete blood from abundant proteins and enrich it in low abundance proteins through several types of particles and protocols, i.e. allowing for detection of low abundance proteins by LC-MS.

We will apply this methodology for the quantification of the 22 and 20 kDa proteoforms. We will further expand this strategy for the analysis of the 23 and 45 kDa proteoforms for which little information is available. The former showed a high concentration in post-exercise states. The latter could exist at higher amounts after administration of pharmaceutical GH. We will investigate their relevance within anti-doping analysis.

At the same time, we will purify blood extracellular microvesicles from blood samples to assess potential GH detection. These vesicles represent a blood sub-type of samples that have a much reduced matrix complexity as compared to blood. As such, the detection of low abundance proteins by LC-MS in this type of samples is significantly more accessible.

Main Findings:

Here we have explored three different strategies for GH purification from plasma samples through antibody-based, precipitation-based and ProteoCAP-based protocols, aimed for a later LC-MS/MS quantification. This quantification has also moved from the previous SRM method to a state-of-the-art PRM method that employed last-generation orbitrap-based instruments. From the three strategies, best results corresponded to precipitation based protocols that were combined with a subsequent fractionation at the protein level with disposable C4 TopTip micro-columns. Together with the PRM method and the use of trypsin, an enzyme that has a higher proteolysis efficacy than the previous Glu-C and that here we have been able to use it due to a new LC gradient configuration, our method detected GH at the spiked concentration of 5 ng/mL of each 20 and 22 kDa proteoform.

This sensitivity does not reflect the presumed true limit of detection, but it is comparable from what we obtained with our previous method, albeit here without the usage of antibodies and with potential improvements that makes
us believe that we will be able to lower these values. Currently we have three precipitation-based methods that could be all of them valid for GH detection. We have unsuccessfully tried to concatenate these methods with additional protocols for further fractionation to gain more sensitivity. We attribute these results to a too reduced protein recovery after the precipitation methods. This low recovery did maximize the impact of the protein losses that occur in any sample preparation step. This led us to escalate these protocols to provide 3-4 times higher protein recovery, where we succeed, and importantly we also succeed in removing the phospholipid contamination that was also escalated in the protocols. As a result we have protocols that now have sufficient protein amount to be amenable for concatenation of additional protocols for increased GH enrichment.

Thus, the next steps of this project will be to test the escalated protocols with and without added concatenated protocols by LC-MS to determine the assay sensitivity and to evaluate its suitability as a method for GH quantification. We believe that the strategy that we have developed in this project has the potential for detecting GH below the ng/mL frontier, thus being able to quantify GH variants at levels close to basal state.