Citation

Owens TS, Calverley TA, Stacey BS, Rose G, Fall L, Tsukamoto H, Jones G, Corkill R, Tuaillon E, Hirtz C, Lehmann S, Marchi N, Marley CJ, Bailey DM. Scand. J. Med. Sci. Sports 2021; ePub(ePub): ePub.

Copyright

(Copyright © 2021, John Wiley and Sons)

DOI

10.1111/sms.14046

PMID

unavailable

Abstract

Recurrent contact and concussion in rugby union remains a significant public health concern given the potential increased risk of neurodegeneration in later-life. This study determined to what extent prior-recurrent contact impacts molecular-haemodynamic biomarkers underpinning cognition in current professional rugby union players with a history of concussion. Measurements were performed in 20 professional rugby union players with an average of 16 [interquartile range (IQR), 13-19] years playing history, reporting 3 (IQR, 1-4) concussions. They were compared to 17 sex-, age-, physical activity- and education-matched non-contact controls with no prior history of self-reported concussion. Venous blood was assayed directly for the ascorbate free radical (A(•-) , electron paramagnetic resonance spectroscopy), nitric oxide metabolites (NO, reductive ozone-based chemiluminescence) and select biomarkers of neurovascular unit integrity (NVU, chemiluminescence/ELISA). Middle cerebral artery blood flow velocity (MCAv, doppler ultrasound) was employed to determine basal perfusion and cerebrovascular reactivity (CVR) to hyper/hypocapnia (CVR(CO2HYPER/HYPO) ). Cognition was assessed by neuropsychometric testing. Elevated systemic oxidative-nitrosative stress was confirmed in the players through increased A(•-) (P < 0.001) and suppression of NO bioavailability (P < 0.001). This was accompanied by a lower CVR range (CVR(CO2RANGE) , P = 0.045)(,) elevation in neurofilament light-chain (P = 0.010) and frontotemporal impairments in immediate-memory (P = 0.001), delayed-recall (P = 0.048) and fine-motor coordination (P < 0.001). Accelerated cognitive decline subsequent to prior recurrent contact and concussion history is associated with a free radical-mediated suppression of CVR and neuronal injury providing important mechanistic insight that may help better inform clinical management.

Language: en

Keywords

Concussion; Cognition; Rugby Union; Cerebral Blood Flow; Free Radicals