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Drug testing and analysis2024; 17(7); 989-996; doi: 10.1002/dta.3795

Bayesian Individual Limits for IGF-1 Monitoring in Equine Plasma: Implementation in the Equine Biological Passport.

Abstract: Despite the International Federation of Horseracing Authorities (IFHA) regulation associated with heavy sanctions, the abuse of prohibited substances must be identified and deterred throughout horses' athletic careers, such as the administration of recombinant growth hormone (rGH). GH is naturally produced in mammal organisms to stimulate growth. Thus, rGH administration can enhance the performance of horses by expanding some physical abilities. As measuring endogenous GH levels is complex, an indirect strategy is to monitor GH-associated biomarkers in plasma as insulin-like growth factor 1 (IGF-1) levels. To prevent these misuses, the Equine Biological Passport (EBP) has been designed in France (GIE LCH) and Australia (ARFL-Racing NSW) to profile specific biological and chemical parameters in selected racehorses. In this study, we investigated individual limits as a complementary tool to a single limit to supervise the stability of IGF-1 profile over a racing season. The aim is to design custom limits based on the horse's history to detect any deviation below the single limit. The method was assessed using experimental data and then tested on EBP data from three thoroughbreds and three French trotters. Finally, individual limits have been added to the French EBP for IGF-1 monitoring.
© 2024 John Wiley & Sons Ltd.
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Publication Date: 2024-09-16 PubMed ID: 39279508DOI: 10.1002/dta.3795Google Scholar: Lookup
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Summary

This research summary has been generated with artificial intelligence and may contain errors and omissions. Refer to the original study to confirm details provided. Submit correction.

Bayesian methods were used to create personalized monitoring limits for insulin-like growth factor 1 (IGF-1) levels in horses to better detect misuse of growth hormone during their racing careers.

Background and Objective

  • The International Federation of Horseracing Authorities (IFHA) enforces regulations against the abuse of prohibited substances in racehorses, including recombinant growth hormone (rGH).
  • Growth hormone (GH) naturally stimulates growth in mammals, and synthetic rGH administration can enhance performance by augmenting physical abilities in horses.
  • Direct measurement of endogenous GH is difficult, so insulin-like growth factor 1 (IGF-1), a biomarker associated with GH activity, is measured in plasma instead.
  • The Equine Biological Passport (EBP) was developed in France and Australia to track biological and chemical parameters over time in racehorses.
  • This study’s goal was to implement Bayesian-based individual limits for IGF-1 monitoring rather than relying solely on single fixed threshold limits.
  • These individual limits aim to account for each horse’s historical IGF-1 values to detect deviations indicative of illicit rGH administration.

Methodology

  • The research used Bayesian statistical methods to generate individual-specific monitoring limits for IGF-1 levels based on historical data of each horse.
  • The approach was validated with experimental IGF-1 data to test its effectiveness in detecting abnormal fluctuations.
  • The method was then applied to real-world data from the Equine Biological Passport, including data from three thoroughbreds and three French trotters.
  • IGF-1 level measurements across a racing season were analyzed to establish personalized reference ranges for each equine athlete.
  • Comparisons were made between single population-wide limits and these Bayesian individual limits to evaluate sensitivity and specificity in detecting potential doping events.

Results and Implementation

  • The Bayesian individual limits successfully identified deviations in IGF-1 levels that might be missed by single fixed limits, thereby enhancing monitoring sensitivity.
  • The personalized limits consider natural intra-individual variation in biomarker levels, reducing false positives caused by natural fluctuations.
  • This method improved detection capabilities for potential misuse of growth hormone during the horse’s athletic career.
  • Individual limits for IGF-1 were integrated into the French Equine Biological Passport system to strengthen anti-doping surveillance.
  • The implementation allows regulatory bodies to more effectively monitor and sanction the illegal administration of rGH by detecting suspicious biomarker profiles.

Significance and Future Directions

  • The study demonstrates the value of individualized biological monitoring in the equine context, similar to human athlete biological passport programs.
  • By adapting monitoring strategies to each horse’s baseline, this approach minimizes both missed cases and false alerts.
  • The framework could be extended to other biomarkers and doping agents, enhancing the overall integrity of horse racing.
  • Collaborations among regulatory authorities such as GIE LCH in France and ARFL-Racing NSW in Australia highlight international efforts to combat doping.
  • Further research could refine the Bayesian models and expand datasets to improve robustness and applicability across diverse equine populations.

Cite This Article

APA
Barnabé A, Loup B, Cawley A, Delcourt V, Garcia P, Popot MA, Keledjian J, Bailly-Chouriberry L. (2024). Bayesian Individual Limits for IGF-1 Monitoring in Equine Plasma: Implementation in the Equine Biological Passport. Drug Test Anal, 17(7), 989-996. https://doi.org/10.1002/dta.3795

Publication

Drug testing and analysis
ISSN: 1942-7611
NlmUniqueID: 101483449
Country: England
Language: English
Volume: 17
Issue: 7
Pages: 989-996

Researcher Affiliations

Barnabé, Agnès
  • GIE LCH, Laboratoire des Courses Hippiques, Verrières-le-Buisson, France.
Loup, Benoit
  • GIE LCH, Laboratoire des Courses Hippiques, Verrières-le-Buisson, France.
Cawley, Adam
  • Australian Racing Forensic Laboratory, Racing NSW, Sydney, New South Wales, Australia.
Delcourt, Vivian
  • GIE LCH, Laboratoire des Courses Hippiques, Verrières-le-Buisson, France.
Garcia, Patrice
  • GIE LCH, Laboratoire des Courses Hippiques, Verrières-le-Buisson, France.
Popot, Marie-Agnès
  • GIE LCH, Laboratoire des Courses Hippiques, Verrières-le-Buisson, France.
Keledjian, John
  • Australian Racing Forensic Laboratory, Racing NSW, Sydney, New South Wales, Australia.
Bailly-Chouriberry, Ludovic
  • GIE LCH, Laboratoire des Courses Hippiques, Verrières-le-Buisson, France.

MeSH Terms

  • Animals
  • Horses / blood
  • Insulin-Like Growth Factor I / analysis
  • Doping in Sports / prevention & control
  • Bayes Theorem
  • Substance Abuse Detection / methods
  • Substance Abuse Detection / veterinary
  • Recombinant Proteins / blood
  • Growth Hormone / blood
  • Growth Hormone / administration & dosage
  • Limit of Detection
  • France
  • Biomarkers / blood

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