Serum SNTF increases in concussed professional ice hockey players and relates to the severity of post-concussion symptoms
Siman R., Shahim P., Tegner .Y, Blennow K., Zetterberg H., Smith DH. J Neuroscience. 2014; ahead of print
Take Home Message: Biomarkers in the blood, such as SNTF, are elevated for up to 6 days following a concussion compared with preseason levels. This marker may eventually be developed to determine diagnosis and prognosis after a concussion as well as guiding return-to-play decisions.
Following a concussion, long-lasting brain dysfunction may relate to widespread damage to axons. Unfortunately, there is no established method to identify concussions that may lead to long-lasting dysfunction at an early, treatable stage. One possible candidate is an alpha II-spectrin N-terminal fragment (SNTF), which is a fragment of a protein that is part of the axon’s cytoskeleton. SNTF increases in blood after an injury but it has not been studied as a marker for sports-related concussion. Therefore, the authors evaluated whether serum SNTF is a diagnostic and prognostic biomarker for concussion in a prospective cohort involving professional ice hockey players from 12 teams within the Swedish Hockey League (288 players). The authors collected preseason serum from 45 players (2 teams) and 17 of these players provided another sample 1 and 12 hours after a training game without concussion. Among the 288 total players, 28 players had concussions and the team physicians obtained blood samples 1 hour (25 players), 12 hours (22 players), 36 hours (20 players), 144 hours (18 players) following the concussion, as well as on the day of return to play (10 players). At preseason, serum levels of SNTF were so low that in 58% of the players the authors couldn’t detect any SNTF. SNTF serum levels remained unchanged at 1 and 12 hours following a training game. Average SNTF concentrations were up to 2-times higher at 12, 36, and 144 post-concussion compared with preseason levels. SNTF levels at 36 hours had the best ability to accurately diagnose a concussion and predict who would experience persistent post-concussion symptoms that delayed the return to play for 6 or more days.
This study is important because it demonstrates the potential to diagnose a concussion with a blood test. This longitudinal study found that SNTF serum concentration increases as early as 1 hour post injury and remains elevated up to return to play. Additionally, serum SNTF levels during the subacute phase after a concussion may enable diagnosis of a concussion and predicting who may have prolonged symptoms. Measuring serum at 36 hours after an injury may be easier than obtaining samples 1 hour after a concussion, as was done in prior studies. Future research will need to verify if SNTF could also be an objective test for making return-to-play decisions. Forty-two percent of the preseason serum samples were above the lower limit of detection, which suggests this marker may be elevated due to factors like a history of concussion or smaller repetitive blows. Therefore, future research should investigate if concussion injury from several repetitive blows would also change the SNTF levels. While more research will be needed this study shows that we may someday be able to use blood tests to diagnose concussions and predict who is at risk for a prolonged recovery. Today, we can also use these results to explain to our patient, coach, and patient’s family that there is evidence that even though we can’t see the damage from concussions – like we can with other sports-related injuries – there is tissue damage that we can measure with blood tests.
Questions for Discussion: Do you see your athletes within 36 hours after a concussed injury? Do you think biomarkers are the next new concussion diagnosis tool?
Written by: Jane McDevitt, PhD
Reviewed by: Jeff Driban