Shortened telomeres and serum protein biomarker abnormalities in collision sport athletes regardless of concussion history and sex

Abstract

Mild brain injuries are frequent in athletes engaging in collision sports and have been linked to a range of long-term neurological abnormalities. There is a need to identify how these potential abnormalities manifest using objective measures; determine whether changes are due to concussive and/or sub-concussive injuries; and examine how biological sex affects outcomes. This study investigated cognitive, cellular, and molecular biomarkers in male and female amateur Australian footballers (i.e. Australia’s most participated collision sport). 95 Australian footballers (69 males, 26 females), both with and without a history of concussion, as well as 49 control athletes (28 males, 21 females) with no history of brain trauma or participation in collision sports were recruited to the study. Ocular motor assessment was used to examine cognitive function. Telomere length, a biomarker of cellular senescence and neurological health, was examined in saliva. Serum levels of tau, phosphorylated tau, neurofilament light chain, and 4-hydroxynonenal were used as markers to assess axonal injury and oxidative stress. Australian footballers had reduced telomere length (p = 0.031) and increased serum protein levels of 4-hydroxynonenal (p = 0.001), tau (p = 0.007), and phosphorylated tau (p = 0.036). These findings were independent of concussion history and sex. No significant ocular motor differences were found. Taken together, these findings suggest that engagement in collision sports, regardless of sex or a history of concussion, is associated with shortened telomeres, axonal injury, and oxidative stress. These saliva- and serum-based biomarkers may be useful to monitor neurological injury in collision sport athletes.

Paternal exposure to exercise and/or caffeine and alcohol modify offspring behavioral and pathophysiological recovery from repetitive mild traumatic brain injury in adolescence

“…Telomeres act as capping structures on chromosomes protecting coding sequences from degradation 76 . Telomere length is altered by numerous environmental and genetic factors and our research group has identified decreased telomere length in preclinical and clinical RmTBI cohorts 51,77,78 . Similar to our behavioral results, following recovery from RmTBI, paternal experience was the primary manipulation driving changes in telomere length in both female and male offspring.…”

The Impact of Concussion, Sport, and Time in Season on Saliva Telomere Length in Healthy Athletes

“…Previous animal research investigating TL collected from the skin following concussion has found TL to be significantly shortened post-concussion (Hehar and Mychasiuk, 2016 ). In contrast, when Symons et al surveyed 97 Australian footballers, they found that although a history of concussion did not influence saliva TL, participation in contact sports did (Symons et al, 2020 ). The discrepancy in these studies could perhaps be due to the timing of collection in relation to concussion recency.…”

“…The authors found a single concussion significantly reduced TL in serum compared to sham injury (Hehar and Mychasiuk, 2016 ; Hehar et al, 2017 ). These findings translated into clinical research, where Symons et al found that on average, Australian football players had shorter saliva TL than athletes participating in non-contact sports (Symons et al, 2020 ). Further, a recent systematic review found individuals that participated in aerobic exercise had longer telomeres than inactive controls – especially when the exercise was moderate to high intensity (Lin X. et al, 2019 ).…”

Cognitive ocular motor deficits and white matter damage chronically after sports-related concussion

“… 32 , 33 Furthermore, pathophysiological changes, such as oxidative stress and neuroinflammation, can also result in a secondary injury to white matter, 34 evidence of which has been seen in cohorts similar to this study. 35 , 36 …”