Résumé
ObjectiveTo determine the molecular and cerebral haemodynamic biomarkers associated with sports-related concussion (SRC) and implications for cognition in retired rugby union players. We hypothesised that SRC would be associated with impaired cerebrovascular function and cognition, subsequent to elevated nitrosative stress in the absence of structural damage.DesignCross-sectional.SettingLaboratory.Participants41 males were divided into two groups, 20 retired players aged 65 (mean) ± 5 (SD) years with 3 ± 3 self-reported SRC’s and 21 age, fitness and education matched controls with no history of participation in contact sports or SRC.Interventions (or Assessment of Risk Factors)Recurrently concussed players were compared to controls.Outcome MeasuresCerebral perfusion via middle cerebral artery velocity (MCAv) and cerebral delivery of oxygen (CDO2) were measured at rest and accompanied by venous assessment of NO bioactivity (nitrite [NO] and S-nitrosothiols [RSNO]), neuron-specific enolase (NSE), glial fibrillary acidic protein (GFAP) and neurofilament light (NFL). Cognition was assessed via the Montreal Cognitive Assessment (MoCA).Main ResultsPlayers were characterised by lower NO bioactivity (P = 0.049, 95% CI = 1.02 – 1.22), perfusion (P = 0.007, 95% CI = 2.30 – 13.65) and CDO2 (P = 0.001, 95% CI = 82.67 – 308.02) that translated into mild cognitive impairment (MCI) versus controls (P = 0.020, 95% CI = 0.35 – 3.94). In contrast, no differences in NSE, GFAP or NFL were observed (P > 0.050).ConclusionsCollectively, these findings provide a mechanistic basis to explain the observed decline in cognitive function that may be relevant for the future prediction of dementia.