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Serum neurofilament light concentration increases following a season of american football
  1. Colin Wallace1,
  2. Zetterberg Henrik2,
  3. Henriksen Kim3,
  4. Donkelaar Paul van1
  1. 1School of Health and Exercise Sciences, University of British Columbia Okanagan, Kelowna, Canada
  2. 2Clinical Neurochemistry Laboratory, Sahlgrenska University Hospital, Sweden
  3. 3Nordic Bioscience, Herlev Hovedgade, Herlev, Denmark


Objective To examine neurofilament light (NF-L), a microtubule-associated protein widely regarded to be central nervous system (CNS) specific, concentrations in serum prior to and following a season of contact (American football) and non-contact (cross-country running) in elite, collegiate-aged athletes.

Design Prospective cohort.

Setting Laboratory.

Participants 13 male American football athletes (19±1.2 years) and 11 cross-country runners (20±1.9 years).

Intervention Pre- and post-season blood samples were obtained from all participants and spun at 2000 g for 10 minutes to extract serum. NF-L was detected through the isolation of individual immunocomplexes on pragmatic beads using standard ELISA reagents. The beads were then trapped in single-molecule, femtolitre-sized wells, allowing for a digital readout of each individual bead. The digital nature of this technique allows an average of 1000x sensitivity increase over conventional assays.

Outcome measures Analysis of pre- and post-season serum samples provide NF-L concentrations.

Results Serum samples from American football players showed a significant increase (p=0.04) from pre-season NF-L serum concentrations (95% CI: 6.51 – 9.19 pg/mL) to post-season (95% CI: 7.08 – 11.70 pg/mL). Serum NF-L concentrations in cross-country runners showed no change (p=0.57) from pre-season (95% CI: 5.05 – 6.94 pg/mL) to post-season (95% CI: 5.05 – 6.88 pg/mL).

Conclusions Experiencing repetitive subconcussive head-trauma throughout a season of American football elevates serum NF-L concentrations. This finding indicates multiple head-impacts may lead to CNS axonal damage.

Competing interests None.

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