Alanazi, NFitzgerald, MHume, PHellewell, SHorncastle, AAnyaegbu, CPapini, MGHargreaves, NHalicki, MEntwistle, IHind, KChazot, P2024-09-032024-09-032024-07-17International Journal of Molecular Sciences, ISSN: 1422-0067 (Print); 1422-0067 (Online), MDPI AG, 25(14), 7811-. doi: 10.3390/ijms251478111422-00671422-0067http://hdl.handle.net/10292/17967The health and well-being of retired rugby union and league players, particularly regarding the long-term effects of concussions, are of major concern. Concussion has been identified as a major risk factor for neurodegenerative diseases, such as Alzheimer’s and Amyotrophic Lateral Sclerosis (ALS), in athletes engaged in contact sports. This study aimed to assess differences in specific biomarkers between UK-based retired rugby players with a history of concussion and a non-contact sports group, focusing on biomarkers associated with Alzheimer’s, ALS, and CTE. We randomly selected a sample of male retired rugby or non-contact sport athletes (n = 56). The mean age was 41.84 ± 6.44, and the mean years since retirement from the sport was 7.76 ± 6.69 for participants with a history of substantial concussions (>5 concussions in their career) (n = 30). The mean age was 45.75 ± 11.52, and the mean years since retirement was 6.75 ± 4.64 for the healthy controls (n = 26). Serum biomarkers (t-tau, RBP-4, SAA, Nf-L, and retinol), plasma cytokines, and biomarkers associated with serum-derived exosomes (Aβ42, p-tau181, p-tau217, and p-tau231) were analyzed using validated commercial ELISA assays. The results of the selected biomarkers were compared between the two groups. Biomarkers including t-tau and p-tau181 were significantly elevated in the history of the substantial concussion group compared to the non-contact sports group (t-tau: p < 0.01; p-tau181: p < 0.05). Although between-group differences in p-tau217, p-tau231, SAA, Nf-L, retinol, and Aβ42 were not significantly different, there was a trend for higher levels of Aβ42, p-tau217, and p-tau231 in the concussed group. Interestingly, the serum-derived exosome sizes were significantly larger (p < 0.01), and serum RBP-4 levels were significantly reduced (p < 0.05) in the highly concussed group. These findings indicate that retired athletes with a history of multiple concussions during their careers have altered serum measurements of exosome size, t-tau, p-tau181, and RBP-4. These biomarkers should be explored further for the prediction of future neurodegenerative outcomes, including ALS, in those with a history of concussion.© 2024 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).https://creativecommons.org/licenses/by/4.0/biomarkersbrain injuryconcussionneurodegenerative diseasesport3101 Biochemistry and Cell Biology31 Biological Sciences3404 Medicinal and Biomolecular Chemistry34 Chemical Sciences3107 MicrobiologyTraumatic Head and Spine InjuryDementiaTraumatic Brain Injury (TBI)Brain DisordersNeurosciencesPhysical Injury - Accidents and Adverse EffectsAcquired Cognitive ImpairmentAgingNeurodegenerativeClinical ResearchPreventionNeurological0399 Other Chemical Sciences0604 Genetics0699 Other Biological SciencesChemical Physics3101 Biochemistry and cell biology3107 Microbiology3404 Medicinal and biomolecular chemistryHumansBiomarkersMaleBrain ConcussionMiddle AgedUnited KingdomRetirementFootballAdultAthletesNeurodegenerative DiseasesRugbytau ProteinsRisk FactorsRetinol-Binding Proteins, PlasmaAthletic InjuriesHumansBrain ConcussionNeurodegenerative DiseasesAthletic Injuriestau ProteinsRisk FactorsFootballRetirementAdultMiddle AgedMaleRetinol-Binding Proteins, PlasmaAthletesBiomarkersUnited KingdomRugbyHumansBiomarkersMaleBrain ConcussionMiddle AgedUnited KingdomRetirementFootballAdultAthletesNeurodegenerative DiseasesRugbytau ProteinsRisk FactorsRetinol-Binding Proteins, PlasmaAthletic InjuriesJournal ArticleOpenAccess10.3390/ijms25147811