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Home / Equine Research Bank / Equine Vet J / Exercise-specific plasma proteomic signatures in racehorses:...
Equine veterinary journal2025; doi: 10.1002/evj.70146

Exercise-specific plasma proteomic signatures in racehorses: Candidates for training adaptation and peak load monitoring.

Abstract: Racehorses undergo profound physiological changes with training and competition, but current biomarkers inadequately capture the complex molecular dynamics of exercise. This study aimed to identify novel plasma biomarkers of training adaptation and peak load using high-throughput proteomics. Objective: We hypothesised that systematic training and racing induce distinct plasma proteomic signatures, enabling the discovery of candidate biomarkers linked to training status, oxidative stress, inflammation and metabolic remodelling. Methods: In vivo longitudinal study. Methods: Forty-nine Arabian and Thoroughbred racehorses underwent standardised high-intensity training. Plasma samples were collected at rest, immediately post-exercise and after recovery during three phases: initial training (T1), mid-season conditioning (T2) and race-phase (R). In total, 314 samples were analysed using tandem mass tags based quantitative proteomics and Orbitrap mass spectrometry. Protein abundance changes were assessed with multiple-testing correction (q < 0.05), and pathway enrichment was performed using STRING and ShinyGO. Results: Proteomic responses differed by phase. T1 showed broad activation of inflammatory (S100A8/A9), antioxidant (superoxide dismutase 1, catalase) and metabolic proteins (glucose-6-phosphate dehydrogenase, phosphoglycerate kinase 1). T2 displayed a more refined profile with remodelling and redox regulators (decorin, thymosin β4, glutathione S-transferase). Racing elicited the strongest response, with over 100 up-regulated proteins linked to energy metabolism, oxidative defense and cytoskeletal adaptation. Several proteins: including S100A8, thymosin β4, prothymosin-α, cofilin-1 and lipocalins, were consistently modulated across phases, highlighting their biomarker potential. Conclusions: Breed imbalance and incomplete follow-up sampling may affect generalisability. Validation in larger, diverse cohorts with targeted assays is required. Conclusions: This study identifies a panel of promising plasma proteins as candidate biomarkers of exercise adaptation and overload in racehorses. These findings may support improved monitoring of performance, training load and early detection of overtraining in equine athletes.
© 2025 The Author(s). Equine Veterinary Journal published by John Wiley & Sons Ltd on behalf of EVJ Ltd.
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Publication Date: 2025-12-29 PubMed ID: 41461583DOI: 10.1002/evj.70146Google Scholar: Lookup
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Summary

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Overview

  • This study investigated plasma proteins that change in response to training and racing in racehorses, aiming to discover new biomarkers that reflect training adaptation and peak physical load.
  • Using high-throughput proteomics across different training phases, the researchers identified specific protein signatures linked to inflammation, oxidative stress, metabolism, and muscle remodeling that could help monitor equine athletic performance and overtraining.

Study Objective and Hypothesis

  • The researchers sought to overcome the limitations of current biomarkers in capturing the complex molecular changes in horses during training and competition.
  • They hypothesized that systematic training and racing induce distinct plasma proteomic signatures, which can be identified as candidate biomarkers associated with:
    • Training status
    • Oxidative stress
    • Inflammation
    • Metabolic remodeling

Study Design and Methods

  • The study was an in vivo longitudinal design involving 49 Arabian and Thoroughbred racehorses undergoing standardized high-intensity training.
  • Plasma samples were collected at three key time points during three different training phases:
    • Rest, immediately post-exercise, and after recovery
    • Phases: initial training (T1), mid-season conditioning (T2), and race-phase (R)
  • In total, 314 plasma samples were analyzed.
  • Proteomic analysis was performed using:
    • Tandem Mass Tags (TMT)-based quantitative proteomics
    • Orbitrap mass spectrometry
  • Statistical analysis included multiple-testing correction (q < 0.05) to identify significant protein abundance changes.
  • Pathway enrichment analysis was done using STRING and ShinyGO tools to interpret functional changes at the molecular level.

Key Findings and Proteomic Signatures

  • Proteomic responses varied significantly across the different training phases:
  • Initial Training (T1):
    • Broad activation of inflammatory proteins such as S100A8 and S100A9.
    • Upregulation of antioxidant enzymes like superoxide dismutase 1 and catalase.
    • Increase in metabolic proteins involved in glucose metabolism such as glucose-6-phosphate dehydrogenase and phosphoglycerate kinase 1.
  • Mid-Season Conditioning (T2):
    • More refined protein profile indicating tissue remodeling and redox regulation.
    • Increased levels of decorin and thymosin β4 linked to extracellular matrix modulation and cytoskeletal organization.
    • Elevated glutathione S-transferase, an enzyme involved in oxidative stress defense.
  • Race Phase (R):
    • Strongest proteomic response with over 100 proteins upregulated.
    • Proteins related to energy metabolism, oxidative defense, and cytoskeletal adaptation showed marked increases.
  • Certain proteins like S100A8, thymosin β4, prothymosin-α, cofilin-1, and various lipocalins were consistently modulated across all phases, suggesting strong potential as biomarkers.

Interpretation and Biological Insights

  • The findings highlight complex molecular adaptations involving inflammation modulation, enhanced antioxidant defenses, alterations in energy metabolism, and structural reorganization of muscles during the course of training and racing.
  • Proteins identified reflect physiological processes critical to adapting to sustained high-intensity exercise and peak physical load in racehorses.
  • Proteins like S100A8/A9 indicate inflammatory responses, while enzymes such as superoxide dismutase and catalase point towards increased oxidative stress handling.
  • Changes in cytoskeletal proteins and extracellular matrix components reveal ongoing tissue remodeling essential for performance improvements and injury prevention.

Limitations and Future Directions

  • The study acknowledges potential limitations including:
    • Breed imbalance between Arabian and Thoroughbred horses, which may influence protein expression profiles.
    • Incomplete follow-up sampling could affect the comprehensiveness of the longitudinal data.
  • To improve generalizability, validation studies in larger and more diverse horse cohorts are needed.
  • Future research should focus on targeted assays for the candidate proteins to confirm their utility as reliable biomarkers.

Conclusions and Practical Applications

  • This study presents a novel panel of plasma proteins as promising candidate biomarkers for monitoring exercise adaptation and peak load in racehorses.
  • These biomarkers could have practical applications in:
    • Tracking training progress and physiological adaptations in equine athletes.
    • Optimizing training loads to maximize performance while minimizing risk of overtraining or injury.
    • Early detection of overtraining syndrome through biomolecular signatures.
  • Overall, the integrative proteomic approach deepens understanding of the molecular underpinnings of equine performance and provides a foundation for precision management of racehorse training and health.

Cite This Article

APA
Grzędzicka J, Świderska B, Sitkiewicz E, Dąbrowska I, Witkowska-Piłaszewicz O. (2025). Exercise-specific plasma proteomic signatures in racehorses: Candidates for training adaptation and peak load monitoring. Equine Vet J. https://doi.org/10.1002/evj.70146

Publication

Equine veterinary journal
ISSN: 2042-3306
NlmUniqueID: 0173320
Country: United States
Language: English

Researcher Affiliations

Grzędzicka, Jowita
  • Department of Large Animal Diseases and Clinic, Institute of Veterinary Medicine, Warsaw University of Life Sciences, Warsaw, Poland.
Świderska, Bianka
  • Mass Spectrometry Laboratory, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland.
Sitkiewicz, Ewa
  • Mass Spectrometry Laboratory, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland.
Dąbrowska, Izabela
  • Department of Large Animal Diseases and Clinic, Institute of Veterinary Medicine, Warsaw University of Life Sciences, Warsaw, Poland.
Witkowska-Piłaszewicz, Olga
  • Department of Large Animal Diseases and Clinic, Institute of Veterinary Medicine, Warsaw University of Life Sciences, Warsaw, Poland.

Grant Funding

  • 2021/41/B/NZ7/03548 / Narodowe Centrum Nauki
  • Science Development Fund of the Warsaw University of Life Sciences-SGGW

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