title: Altered Blood Biomarker Profiles in Athletes with a History of Repetitive Head Impacts.
abstract: The long-term health effects of concussion and sub-concussive impacts in sport are unknown. Growing evidence suggests both inflammation and neurodegeneration are pivotal to secondary injury processes and the etiology of neurodegenerative diseases. In the present study we characterized circulating brain injury and inflammatory mediators in healthy male and female athletes according to concussion history and collision sport participation. Eighty-seven university level athletes (male, n = 60; female, n = 27) were recruited before the start of the competitive season. Athletes were healthy at the time of the study (no medications, illness, concussion or musculoskeletal injuries). Dependent variables included 29 inflammatory and 10 neurological injury analytes assessed in the peripheral blood by immunoassay. Biomarkers were statistically evaluated using partial least squares multivariate analysis to identify possible relationships to self-reported previous concussion history, number of previous concussions and collision sport participation in male and female athletes. Multiple concussions were associated with increases in peripheral MCP-1 in females, and MCP-4 in males. Collision sport participation was associated with increases in tau levels in males. These results are consistent with previous experimental and clinical findings that suggest ongoing inflammatory and cerebral injury processes after repetitive mild head trauma. However, further validation is needed to correlate systemic biomarkers to repetitive brain impacts, as opposed to the extracranial effects common to an athletic population such as exercise and muscle damage.
authors.affiliation: Institute of Medical Science, University of Toronto, Toronto ON, Canada.|Defence Research and Development Canada, Toronto Research Centre, Toronto, ON, Canada.
authors.forename: Alex P
authors.initials: AP
authors.lastname: Di Battista
authors.affiliation: Defence Research and Development Canada, Toronto Research Centre, Toronto, ON, Canada.|Faculty of Kinesiology & Physical Education, University of Toronto, Toronto ON, Canada.
authors.forename: Shawn G
authors.initials: SG
authors.lastname: Rhind
authors.affiliation: Faculty of Kinesiology & Physical Education, University of Toronto, Toronto ON, Canada.
authors.forename: Doug
authors.initials: D
authors.lastname: Richards
authors.affiliation: Keenan Research Centre for Biomedical Science of St. Michael's Hospital, Toronto, ON, Canada.
authors.forename: Nathan
authors.initials: N
authors.lastname: Churchill
authors.affiliation: Institute of Medical Science, University of Toronto, Toronto ON, Canada.|Departments of Critical Care, Anesthesia and Surgery, St. Michael's Hospital, University of Toronto, Toronto ON, Canada.|Keenan Research Centre, Li Ka Shing Knowledge Institute, St. Michael's Hospital, Toronto, ON, Canada.
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Baker
authors.affiliation: Faculty of Kinesiology & Physical Education, University of Toronto, Toronto ON, Canada.|Keenan Research Centre for Biomedical Science of St. Michael's Hospital, Toronto, ON, Canada.
authors.forename: Michael G
authors.initials: MG
authors.lastname: Hutchison
mesh_terms: D000293:Adolescent; D056352:Athletes; D001265:Athletic Injuries / Q000097:blood* / Q000150:complications; D015415:Biomarkers / Q000097:blood; D001924:Brain Concussion / Q000097:blood* / Q000209:etiology; D016022:Case-Control Studies; D018932:Chemokine CCL2 / Q000097:blood*; D005260:Female; D006801:Humans; D008297:Male; D018945:Monocyte Chemoattractant Proteins / Q000097:blood*; D055815:Young Adult; D016875:tau Proteins / Q000097:blood*
chemical_list: D015415:Biomarkers; C099677:CCL13 protein, human; C111835:CCL2 protein, human; D018932:Chemokine CCL2; C054369:MAPT protein, human; D018945:Monocyte Chemoattractant Proteins; D016875:tau Proteins