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UBC Theses and Dissertations

Blood-based biomarker alterations in athletes following sub-concussive and concussive impacts Wallace, Colin Anthony


Sport-related concussion affects an estimated 1.6 – 3.8 million people in the United States annually, and it has been suggested many more go unreported due to lack of knowledge regarding symptoms. Current diagnostic measures are based on subjective criteria, which rely heavily on self-reporting by the individual who has suffered the injury. Further, it is possible for symptoms of a concussion to manifest up to 72-hours post-injury, making it even more difficult to form a mechanistic link between trauma and symptoms. Recently, there has been an increased concern for the deleterious physiological effects of repetitive, sub-concussive impacts. An objective, quantifiable measure of the pathophysiological effects of both sub-concussive and concussive impacts is essential for concussion diagnosis, and could aid in tracking the pathophysiological processes underlying acute and repetitive mild traumatic head trauma. Three prospective cohort studies form the backbone of this dissertation. Study 1 examined plasma concentrations of total tau (T-tau), along with serum concentrations of neurofilament light (NF-L), A disintegrin and metalloproteinase domain-containing 10-(ADAM10) and caspase 3-cleaved fragments of tau (Tau-A and Tau-C, respectively) before and after a season of athletic competition in the following sports: American football, ice hockey, rugby, soccer, and cross country running. Study 2 examined NF-L before and after an acute bout of soccer heading. To complete the dissertation, Study 3 involved the quantification of these biomarkers at preseason and at 6- and 14-days following a concussion in American football, ice hockey, and soccer players. Serum NF-L appeared to be more sensitive to the effects of repetitive, sub-concussive impacts (i.e. studies 1 and 2) than a single, traumatic event resulting in a concussion (i.e. study 3), where it did not change. T-tau, Tau-A, and Tau-C were unaffected by both repetitive subconcussive impacts and impacts resulting in a concussion. Thus, it appears that serum NF-L may be a sensitive biomarker of axonal damage in repetitive sub-concussive and concussive contexts.

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