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

Grzędzicka J, Świderska B, Sitkiewicz E, Dąbrowska I, Witkowska-Piłaszewicz O

Equine veterinary journal29 Dec 2025

PMID41461583PMCIDPMC13447926DOI10.1002/evj.70146PepBankPUB-41461583

Summary

BackgroundRacehorses 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.ObjectivesWe 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.Study designIn vivo longitudinal study.MethodsForty-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.ResultsProteomic 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.Main limitationsBreed imbalance and incomplete follow-up sampling may affect generalisability. Validation in larger, diverse cohorts with targeted assays is required.ConclusionsThis 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.

CC BYText from Europe PMC. Highlighted sentences are the source of results.

Results from this study2

No result from this study comes from a test of the peptide.

Natural levels measured2

These results measure the body's own peptide. Nobody was given the peptide. They are not evidence about taking it. They are left out of key results, evidence counts and charts.

01AnimalEndogenous levelAnimal study (in vivo)Other
In racehorses, the body's own plasma thymosin β4 was part of the protein profile that characterised the mid-season conditioning phase; the direction of change is not stated.
In plain wordsIn racehorses, the body's own thymosin β4 in blood was part of the protein changes seen in mid-season training.
Peptide
Thymosin beta-4 (human)
Outcome
Direction not reportedPlasma thymosin β4 in mid-season conditioning (T2)
Study
horsen: not reported in source
Arabian and Thoroughbred racehorses in training
Outcome group
Exercise and physical function · Whole body
Source sentences
Summary
T2 displayed a more refined profile with remodelling and redox regulators (decorin, thymosin β4, glutathione S-transferase).
2 context sentences(design, population, supporting numbers)
Summary · context
Forty-nine Arabian and Thoroughbred racehorses underwent standardised high-intensity training.
Summary · context
In total, 314 samples were analysed using tandem mass tags based quantitative proteomics and Orbitrap mass spectrometry.
This result measures the body's own Thymosin beta-4 (human). Nobody was given the peptide. It is not evidence about taking it.
Show in the study text Report a problemFND-4146158301
02AnimalEndogenous levelAnimal study (in vivo)Other
In racehorses, the body's own plasma thymosin β4 was consistently modulated across training and race phases, which suggests biomarker potential; the direction of change is not stated.
In plain wordsIn racehorses, the body's own thymosin β4 in blood changed consistently across training phases, which may make it a useful marker.
Peptide
Thymosin beta-4 (human)
Outcome
Direction not reportedPlasma thymosin β4 across training and race phases
Study
horsen: not reported in source
Arabian and Thoroughbred racehorses in training
Outcome group
Exercise and physical function · Whole body
Source sentences
Summary
Several proteins: including S100A8, thymosin β4, prothymosin-α, cofilin-1 and lipocalins, were consistently modulated across phases, highlighting their biomarker potential.
2 context sentences(design, population, supporting numbers)
Summary · context
Forty-nine Arabian and Thoroughbred racehorses underwent standardised high-intensity training.
Summary · context
In total, 314 samples were analysed using tandem mass tags based quantitative proteomics and Orbitrap mass spectrometry.
This result measures the body's own Thymosin beta-4 (human). Nobody was given the peptide. It is not evidence about taking it.
Show in the study text Report a problemFND-4146158302

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Version history

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Version 2Current
13 Oct 2026, 01:52 UTC
Study results updated
Version 1
12 Oct 2026, 18:17 UTC
First added · source update from Europe PMC

Subjects

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