1
|
Piper T, Krombholz S, Thevis M. Carbon isotope ratios of phenethylamine and its urinary metabolite phenylacetylglutamine. Drug Test Anal 2023. [PMID: 38048815 DOI: 10.1002/dta.3616] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2023] [Revised: 11/09/2023] [Accepted: 11/09/2023] [Indexed: 12/06/2023]
Abstract
Phenethylamine (PEA) is a naturally occurring trace amine that acts as a modulator in the central nervous system. It is widely sold as a dietary supplement and advertised for its mood enhancing effects and should support weight loss. It is prohibited in sports and itemized as a stimulant on the Prohibited List issued by the World Anti-Doping Agency (WADA). After oral administration of PEA, its urinary concentration is found only slightly elevated while metabolites of PEA show a significant increase. Besides 2-(2-hydroxyphenyl)acetamide sulfate, especially phenylacetylglutamine (PAG) was found at significantly elevated urinary concentrations after the administration. Due to large inter- and intra-individual variations in urinary concentrations of all metabolites, establishing a concentration or concentration ratio-based threshold remained complicated to unambiguously identify post-administration samples. In accordance with the approach employed in detecting testosterone misuse, the applicability of isotope ratio mass spectrometry to differentiate between endogenously elevated concentrations and PEA administrations was investigated. A method encompassing solid-phase extraction combined with acetylation and high-performance liquid chromatography (HPLC)-based clean-up was developed and validated for PEA. The more abundant metabolite PAG was purified by a direct injection approach on the HPLC and could be analyzed without the need for derivatization. Both methods were validated considering applicable WADA regulations. A reference population encompassing n = 57 samples was investigated to establish population-based thresholds considering the carbon isotope ratios (CIRs) found at natural abundance for PAG. The derived threshold was tested for its applicability by re-analysis of numerous post-administration samples encompassing single- and multi-dose trials.
Collapse
Affiliation(s)
- Thomas Piper
- Center for Preventive Doping Research, Institute of Biochemistry, German Sport University Cologne, Cologne, Germany
| | - Sophia Krombholz
- Center for Preventive Doping Research, Institute of Biochemistry, German Sport University Cologne, Cologne, Germany
| | - Mario Thevis
- Center for Preventive Doping Research, Institute of Biochemistry, German Sport University Cologne, Cologne, Germany
- European Monitoring Center for Emerging Doping Agents (EuMoCEDA), Cologne, Germany
| |
Collapse
|
2
|
Thomas A, Krombholz S, Breuer J, Walpurgis K, Thevis M. Insulin-mimetic peptides in sports drug testing. Drug Test Anal 2023; 15:1468-1476. [PMID: 37691519 DOI: 10.1002/dta.3572] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2023] [Revised: 08/25/2023] [Accepted: 08/25/2023] [Indexed: 09/12/2023]
Abstract
Because of its influence on carbohydrate metabolism and, at the same time, anti-catabolic effects, the misuse of the peptide hormone insulin and its synthetic analogs is prohibited in sports at all times according to the regulations of the World Anti-Doping Agency (WADA). The biological effects of insulin and its analogs are mediated through binding to the insulin receptor, which was also found to be activated by different peptides structurally largely unrelated to insulin. Such insulin-mimetic peptides or selective-insulin receptor modulators (SIRMs) represent a novel class of potential performance-enhancing agents, which is currently not explicitly mentioned on the WADA Prohibited List. Within this research project, advanced solid-phase extraction (SPE) and liquid chromatography coupled to high-resolution tandem mass spectrometry (LC-HRMS/MS) were employed to develop a fast, reliable, and specific assay for the detection of the insulin-mimetic peptides S597 and S519 from plasma. Method validation demonstrated a detection limit of 0.5 ng/mL and successfully illustrated the applicability of the approach to routine sports drug testing programs. Moreover, sophisticated and comprehensive in vitro metabolism experiments were conducted, and several metabolic degradation products were identified, which will enhance the information generated from future analyses of doping control samples.
Collapse
Affiliation(s)
- Andreas Thomas
- Institute of Biochemistry/Center for Preventive Doping Research, German Sport University Cologne, Cologne, Germany
| | - Sophia Krombholz
- Institute of Biochemistry/Center for Preventive Doping Research, German Sport University Cologne, Cologne, Germany
| | - Johanna Breuer
- Institute of Biochemistry/Center for Preventive Doping Research, German Sport University Cologne, Cologne, Germany
| | - Katja Walpurgis
- Institute of Biochemistry/Center for Preventive Doping Research, German Sport University Cologne, Cologne, Germany
| | - Mario Thevis
- Institute of Biochemistry/Center for Preventive Doping Research, German Sport University Cologne, Cologne, Germany
- European Monitoring Center for Emerging Doping Agents (EuMoCEDA), Cologne/Bonn, Germany
| |
Collapse
|
3
|
Krombholz S, Thomas A, Delahaut P, Bidlingmaier M, Schilbach K, Miller G, Thevis M. A combined top-down and bottom-up LC-HRMS/MS method for the quantification of human growth hormone in plasma and serum. Growth Horm IGF Res 2023; 72-73:101560. [PMID: 37995539 DOI: 10.1016/j.ghir.2023.101560] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/08/2023] [Revised: 11/03/2023] [Accepted: 11/13/2023] [Indexed: 11/25/2023]
Abstract
OBJECTIVE The precise and accurate quantification of human growth hormone (GH) in plasma/ serum is crucial for the diagnosis and treatment of diseases like GH deficiency or acromegaly. However, the ligand-binding assays (LBAs) currently used for routine testing show considerable methodological variability. Here, we present a complementary, combined top-down and bottom-up LC-MS-based method to quantify (intact) GH in plasma and serum, which concurrently provides a basis for a MS-based analysis of GH in doping controls. DESIGN Extraction of GH from plasma/ serum was accomplished by protein precipitation, followed by an immunocapture step using protein A-coupled magnetic beads and a polyclonal anti-GH antibody. The intact protein was subsequently analyzed top-down on a 2D-LC-HRMS/MS system. In addition, sample extracts were digested with trypsin and analyzed for signal peptides corresponding to 'total', 22 kDa and 20 kDa GH (bottom-up). Both assays were validated according to current guidelines and compared to the GH isoform differential immunoassay used in routine doping control analysis. GH concentrations in serum samples of healthy adults, patients with acromegaly, and in samples obtained after administration of recombinant GH were analyzed as proof-of-principle. RESULTS The intact monomeric 22 kDa isoform of GH was selectively quantified in a representative working range of 0.5 to 10 ng/ml by top-down LC-HRMS/MS. Subsequent bottom-up analysis provided additional data on 'total' and 20 kDa GH. Top-down and bottom-up assay results for the 22 kDa isoform correlated well with the corresponding immunoassay results (R2 > 0.95). For a possible application of the method in an anti-doping context, the ratio between 22 kDa and 'total' GH was evaluated, indicating differences between the various donor groups, but only with limited significance. CONCLUSION The top-down and bottom-up LC-HRMS/MS method developed here presents a valuable tool for the quantification of GH in plasma/ serum complementary to established LBAs used at present in clinical measurements. Albeit the examination of the GH isoform proportions by the LC-MS method does not yet allow for the assessment of GH abuse, the obtained findings provide an important basis to enable LC-MS-based GH analysis of doping control samples in the future.
Collapse
Affiliation(s)
- Sophia Krombholz
- Center for Preventive Doping Research - Institute of Biochemistry, German Sport University Cologne, Germany
| | - Andreas Thomas
- Center for Preventive Doping Research - Institute of Biochemistry, German Sport University Cologne, Germany
| | | | - Martin Bidlingmaier
- Endocrine Research Laboratories, Department of Medicine IV, LMU University Hospital, Munich, Germany
| | - Katharina Schilbach
- Endocrine Research Laboratories, Department of Medicine IV, LMU University Hospital, Munich, Germany
| | - Geoffrey Miller
- Sports Medicine Research and Testing Laboratory, Salt Lake City, UT, USA
| | - Mario Thevis
- Center for Preventive Doping Research - Institute of Biochemistry, German Sport University Cologne, Germany; European Monitoring Center for Emerging Doping Agents (EuMoCEDA), Cologne, Bonn, Germany.
| |
Collapse
|
4
|
Pfeiffer TR, Althoff A, Krombholz S, Dautert M, Naendrup JH, Guenther D, Bouillon B, Thevis M. Vancomycin Concentrations in Synovial Fluid Do Not Reach Chondrotoxic Thresholds After Anterior Cruciate Ligament Reconstruction With Vancomycin-Soaked Autologous Soft Tissue Grafts: An In Vivo Prospective Observational Study in Humans. Am J Sports Med 2023:3635465231169040. [PMID: 37161935 DOI: 10.1177/03635465231169040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
BACKGROUND Studies have revealed that vancomycin soaking of the anterior cruciate ligament (ACL) graft can drastically reduce the incidence of postoperative infections after ACL reconstruction. However, it remains unknown whether the chondrotoxic threshold of vancomycin in synovial fluid is exceeded during this process. Several studies investigated the chondrotoxic properties of vancomycin in in vitro experiments and described a concentration of 1000 µg/mL as the critical threshold. PURPOSE/HYPOTHESIS The purpose of the study was to measure the vancomycin concentration in synovial fluid after ACL reconstruction with vancomycin-soaked autografts. It was hypothesized that intra-articular vancomycin concentrations in the synovial fluid would not reach the chondrotoxic threshold of 1000 µg/mL after vancomycin soaking of autologous semitendinosus tendon and soft tissue quadriceps tendon grafts for ACL reconstruction. STUDY DESIGN Cohort study; Level of evidence, 3. METHODS The study enrolled 10 patients undergoing ACL reconstruction using 4-strand semitendinosus tendon autografts and 10 patients undergoing ACL reconstruction using soft tissue quadriceps tendon autografts. Before implantation, each harvested graft was intraoperatively wrapped in gauze swabs that had been soaked in a 5-mg/mL vancomycin solution. After wound closure, an aspirate of 5 mL of synovial fluid was taken from each patient. The vancomycin concentration of the aspirate was analyzed using high-performance liquid chromatography-tandem mass spectrometry. Spearman rho correlation coefficients were used to identify relationships between the parameters, and the t test was used to test for differences between graft types. A P value of <.05 was considered statistically significant. RESULTS The study included 20 patients (14 women and 6 men; age, 29.35 ± 11.3 years). The mean vancomycin concentration measured in the synovial fluid was 23.23 ± 21.68 µg/mL, with a minimum concentration of 2.32 µg/mL and a maximum concentration of 71.56 µg/mL. No significant difference was found between the 2 graft types (P = .911). Significant positive correlation (r = 0.644; P < .05) was observed only between the vancomycin concentration and the mean duration from initiation of vancomycin soaking of semitendinosus tendon grafts to implantation (13.4 ± 6 minutes). No correlations were observed between the vancomycin concentration and the duration from implantation to fluid aspiration or between the vancomycin concentration and the graft diameter (median, 8.5 mm; range, 6.0-10.0 mm) for both graft types. CONCLUSION Chondrotoxic vancomycin concentrations ≥1000 µg/mL were not reached in any aspiration of synovial fluid after ACL reconstruction using soft tissue autografts that were intraoperatively soaked in a 5-mg/mL vancomycin solution. Against the backdrop of multiple studies that showed significantly reduced infection rates after ACL reconstruction when vancomycin soaking was used, this study suggests that the chondrotoxic properties of this method are negligible because of its submarginal intra-articular concentrations.
Collapse
Affiliation(s)
- Thomas R Pfeiffer
- Cologne Merheim Medical Center, Witten/Herdecke University, Cologne, Germany
| | - Arne Althoff
- Department of Experimental Sports Traumatology, Witten/Herdecke University, Witten, Germany
| | - Sophia Krombholz
- Center for Preventive Doping Research, Institute of Biochemistry, German Sport University Cologne, Cologne, Germany
| | - Max Dautert
- Center for Preventive Doping Research, Institute of Biochemistry, German Sport University Cologne, Cologne, Germany
| | - Jan-Hendrik Naendrup
- Department of Experimental Sports Traumatology, Witten/Herdecke University, Witten, Germany
| | - Daniel Guenther
- Department of Experimental Sports Traumatology, Witten/Herdecke University, Witten, Germany
| | - Bertil Bouillon
- Cologne Merheim Medical Center, Witten/Herdecke University, Cologne, Germany
| | - Mario Thevis
- Center for Preventive Doping Research, Institute of Biochemistry, German Sport University Cologne, Cologne, Germany
| |
Collapse
|
5
|
Krombholz S, Thomas A, Piper T, Lagojda A, Kühne D, Thevis M. Urinary phenylethylamine metabolites as potential markers for sports drug testing purposes. Biomed Chromatogr 2021; 36:e5274. [PMID: 34729800 DOI: 10.1002/bmc.5274] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Revised: 09/16/2021] [Accepted: 10/25/2021] [Indexed: 11/07/2022]
Abstract
The misuse of 2-phenylethylamine (PEA) in sporting competitions is prohibited by the World Anti-Doping Agency. As it is endogenously produced, a method is required to differentiate between naturally elevated levels of PEA and the illicit administration of the drug. In 2015, a sulfo-conjugated metabolite [2-(2-hydroxyphenyl)acetamide sulfate (M1)] was identified, and pilot study data suggested that the ratio M1/PEA could be used as a marker indicating the oral application of PEA. Within this project, the required reference material of M1 was synthesized, single and multiple dose elimination studies were conducted and 369 native urine samples of athletes were analyzed as a reference population. While the oral administration of only 100 mg PEA did not affect urinary PEA concentrations, an increase in urinary concentrations of M1 was observed for all volunteers. However, urinary concentrations of both PEA and M1 showed relatively large inter-individual differences and establishing a cut-off-level for M1/PEA proved difficult. Consequently, a second metabolite, phenylacetylglutamine, was considered. Binary logistic regression demonstrated a significant (P < 0.05) correlation of the urinary M1 and phenylacetylglutamine concentrations with an oral administration of PEA, suggesting that assessing both analytes can assist doping control laboratories in identifying PEA misuse.
Collapse
Affiliation(s)
- Sophia Krombholz
- Center for Preventive Doping Research-Institute of Biochemistry, German Sport University Cologne, Cologne, Germany
| | - Andreas Thomas
- Center for Preventive Doping Research-Institute of Biochemistry, German Sport University Cologne, Cologne, Germany
| | - Thomas Piper
- Center for Preventive Doping Research-Institute of Biochemistry, German Sport University Cologne, Cologne, Germany
| | | | - Dirk Kühne
- Crop Science Division, Bayer AG, Monheim, Germany
| | - Mario Thevis
- Center for Preventive Doping Research-Institute of Biochemistry, German Sport University Cologne, Cologne, Germany
- European Monitoring Center for Emerging Doping Agents (EuMoCEDA), Cologne/Bonn, Germany
| |
Collapse
|
6
|
Thomas A, Krombholz S, Wolf C, Thevis M. Determination of ghrelin and desacyl ghrelin in human plasma and urine by means of LC-MS/MS for doping controls. Drug Test Anal 2021; 13:1862-1870. [PMID: 34633773 DOI: 10.1002/dta.3176] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2021] [Revised: 09/29/2021] [Accepted: 09/30/2021] [Indexed: 11/08/2022]
Abstract
The hunger hormone ghrelin (G) is classified as prohibited substance in professional sport by the World Anti-Doping Agency (WADA), due to its known growth hormone releasing properties. The endogenous bioactive peptide consists of 28 amino acids with a caprylic acid attached to serine at position 3. Within this study, it was aimed to develop methods to determine G and desacyl ghrelin (DAG) in plasma and urine by means of LC-MS/MS. Two strategies were applied with a bottom-up approach for plasma and top-down analyses for urine. Both sample preparation procedures were based on solid-phase extraction for enrichment and sample clean-up. Method validation showed good results for plasma and urine with limits of detection (LODs) for G and DAG between 30 and 50 pg/ml, recoveries between 45-50%, and imprecisions (intra- and inter-day) between 3% and 24%. Plasma analysis was also valid for quantification with accuracies determined with ~100% for G and ~106% for DAG. The minimum required performance level for doping control laboratories is set to 2 ng/ml in urine, and the herein established method yielded acceptable results even at 5% of this level. As proof-of-concept, plasma levels (G and DAG) of healthy volunteers were determined and ranged between 30 and 100 pg/ml for G and 100-1200 pg/ml for DAG. In contrast to earlier reported studies using ligand binding assays for urinary G and DAG, in this mass spectrometry-based study, no endogenous urinary G and DAG were found, although the LODs should enable this.
Collapse
Affiliation(s)
- Andreas Thomas
- Institute of Biochemistry/Center for Preventive Doping Research, German Sport University Cologne, Cologne, Germany
| | - Sophia Krombholz
- Institute of Biochemistry/Center for Preventive Doping Research, German Sport University Cologne, Cologne, Germany
| | - Carina Wolf
- Institute of Biochemistry/Center for Preventive Doping Research, German Sport University Cologne, Cologne, Germany
| | - Mario Thevis
- Institute of Biochemistry/Center for Preventive Doping Research, German Sport University Cologne, Cologne, Germany.,European Monitoring Center for Emerging Doping Agents (EuMoCEDA), Cologne/Bonn, Germany
| |
Collapse
|