Serum neurofilament light as a biomarker of vulnerability to a second mild traumatic brain injury

Open AccessPublished:November 16, 2022DOI:


      A second mild traumatic brain injury (mTBI) sustained prior to neuropathological recovery can lead to exacerbated effects. Without objective indicators of this neuropathology, individuals may return to activities at risk of mTBI when their brain is still vulnerable. With axonal injury recognized as a neuropathological hallmark of mTBI, we hypothesized that serum levels of neurofilament light (NfL), a highly sensitive biomarker of axonal injury, may be predictive of vulnerability to worse outcomes in the event of a second mTBI. Given this hypothesis is difficult to test clinically, we used a two-hit model of mTBI in rats and staggered inter-injury intervals by 1-, 3-, 7-, or 14-days. Repeat-mTBI rats were dichotomized into NfLhigh (NfL>median at the time of re-injury) and NfLlow (NfL<median) groups, with behavior and NfL levels analyzed throughout the 28-days, followed by ex vivo diffusion tensor imaging. NfL levels at the time of the second mTBI were found to be predictive of vulnerability to re-injury, with NfLhigh rats displaying more neurological signs and a greater potentiation of NfL levels after the second mTBI. Importantly, this potentiation phenomenon remained even when limiting analyses to rats with longer inter-injury intervals, providing evidence that vulnerability to re-injury may not be exclusively dependent on inter-injury interval. Finally, NfL levels correlated with, and were predictive of, the severity of neurological signs following the second mTBI. These findings provide evidence that measurement of NfL during mTBI recovery may be reflective of the vulnerability to a second mTBI, and as such may have utility to assist return to sport, duty and work decisions.
      To read this article in full you will need to make a payment

      Purchase one-time access:

      Academic & Personal: 24 hour online accessCorporate R&D Professionals: 24 hour online access
      One-time access price info
      • For academic or personal research use, select 'Academic and Personal'
      • For corporate R&D use, select 'Corporate R&D Professionals'


      Subscribe to Translational Research
      Already a print subscriber? Claim online access
      Already an online subscriber? Sign in
      Institutional Access: Sign in to ScienceDirect


      1. Faul M, Wald MM, Xu L, Coronado VG. Traumatic brain injury in the United States; emergency department visits, hospitalizations, and deaths, 2002-2006. 2010.

        • Meehan 3rd, WP
        • Mannix R.
        Pediatric concussions in United States emergency departments in the years 2002 to 2006.
        J Pediatr. 2010; 157: 889-893
        • Levin HS
        • Diaz-Arrastia RR.
        Diagnosis, prognosis, and clinical management of mild traumatic brain injury.
        Lancet Neurol. 2015; 14: 506-517
        • Hoge CW
        • McGurk D
        • Thomas JL
        • Cox AL
        • Engel CC
        • Castro CA.
        Mild traumatic brain injury in U.S. soldiers returning from Iraq.
        N Engl J Med. 2008; 358: 453-463
        • Dretsch MN
        • Silverberg ND
        • Iverson GL.
        Multiple past concussions are associated with ongoing post-concussive symptoms but not cognitive impairment in active-duty army soldiers.
        J Neurotrauma. 2015; 32: 1301-1306
        • Miller KJ
        • Ivins BJ
        • Schwab KA.
        Self-reported mild TBI and postconcussive symptoms in a peacetime active duty military population: effect of multiple TBI history versus single mild TBI.
        J Head Trauma Rehabil. 2013; 28: 31-38
        • Iverson GL
        • Gardner AJ
        • Terry DP
        • et al.
        Predictors of clinical recovery from concussion: a systematic review.
        Br J Sports Med. 2017; 51: 941-948
        • Silverberg ND
        • Lange RT
        • Millis SR
        • et al.
        Post-concussion symptom reporting after multiple mild traumatic brain injuries.
        J Neurotrauma. 2013; 30: 1398-1404
        • Eisenberg MA
        • Andrea J
        • Meehan W
        • Mannix R
        Time interval between concussions and symptom duration.
        Pediatrics. 2013; 132: 8-17
        • Kamins J
        • Bigler E
        • Covassin T
        • et al.
        What is the physiological time to recovery after concussion? A systematic review.
        Brit J Sport Med. 2017; : 51
        • Vagnozzi R
        • Tavazzi B
        • Signoretti S
        • et al.
        Temporal window of metabolic brain vulnerability to concussions: mitochondrial-related impairment–part I.
        Neurosurgery. 2007; 61 (discussion 88-9): 379-388
        • Giza CC
        • Prins ML
        • Hovda DA.
        It's not all fun and games: sports, concussions, and neuroscience.
        Neuron. 2017; 94: 1051-1055
        • Vagnozzi R
        • Signoretti S
        • Tavazzi B
        • et al.
        Temporal window of metabolic brain vulnerability to concussion: a pilot 1H-magnetic resonance spectroscopic study in concussed athletes–part III.
        Neurosurg. 2008; 62: 1286-1296
        • McCrory P
        • Meeuwisse W
        • Dvorak J
        • et al.
        Consensus statement on concussion in sport-the 5(th) international conference on concussion in sport held in Berlin, October 2016.
        Br J Sports Med. 2017; 51: 838-847
        • VE Johnson
        • Stewart W
        • Smith DH.
        Axonal pathology in traumatic brain injury.
        Exp Neurol. 2013; 246: 35-43
        • Hill CS
        • Coleman MP
        • Menon DK.
        Traumatic axonal injury: mechanisms and translational opportunities.
        Trends Neurosci. 2016; 39: 311-324
        • Miller DR
        • Hayes JP
        • Lafleche G
        • Salat DH
        • Verfaellie M.
        White matter abnormalities are associated with chronic postconcussion symptoms in blast-related mild traumatic brain injury.
        Hum Brain Mapp. 2016; 37: 220-229
        • McDonald SJ
        • O'Brien WT
        • Symons GF
        • et al.
        Prolonged elevation of serum neurofilament light after concussion in male Australian football players.
        Biomark Res. 2021; 9: 4
        • Shahim P
        • Tegner Y
        • Marklund N
        • Blennow K
        • Zetterberg H.
        Neurofilament light and tau as blood biomarkers for sports-related concussion.
        Neurology. 2018; 90: e1780-e17e8
        • Zetterberg H
        • Blennow K.
        Fluid biomarkers for mild traumatic brain injury and related conditions.
        Nat Rev Neurol. 2016; 12: 563-574
        • Shahim P
        • Zetterberg H
        • Tegner Y
        • Blennow K.
        Serum neurofilament light as a biomarker for mild traumatic brain injury in contact sports.
        Neurology. 2017; 88: 1788-1794
        • Clarke GJB
        • Skandsen T
        • Zetterberg H
        • et al.
        One-year prospective study of plasma biomarkers from CNS in patients with mild traumatic brain injury.
        Front Neurol. 2021; 12643743
        • McDonald SJ
        • Piantella S
        • O'Brien WT
        • et al.
        Clinical and blood biomarker trajectories after concussion: new insights from a longitudinal pilot study of professional flat-track jockeys.
        J Neurotrauma. 2022;
        • O'Brien WT
        • Pham L
        • Brady RD
        • et al.
        Temporal profile and utility of serum neurofilament light in a rat model of mild traumatic brain injury.
        Exp Neurol. 2021; 341113698
        • Pham L
        • Shultz SR
        • Kim HA
        • et al.
        Mild closed-head injury in conscious rats causes transient neurobehavioral and glial disturbances: a novel experimental model of concussion.
        J Neurotrauma. 2019; 36: 2260-2271
        • Pham L
        • Wright DK
        • O'Brien WT
        • et al.
        Behavioral, axonal, and proteomic alterations following repeated mild traumatic brain injury: novel insights using a clinically relevant rat model.
        Neurobiol Dis. 2020; 105151
        • Davis GA
        • Makdissi M
        • Bloomfield P
        • et al.
        International consensus definitions of video signs of concussion in professional sports.
        Br J Sports Med. 2019; 53: 1264-1267
        • Ah Kim H
        • Semple BD
        • Dill LK
        • et al.
        Systemic treatment with human amnion epithelial cells after experimental traumatic brain injury.
        Brain Behav Immun Health. 2020; 5100072
        • Andersson JL
        • Skare S
        • Ashburner J.
        How to correct susceptibility distortions in spin-echo echo-planar images: application to diffusion tensor imaging.
        Neuroimage. 2003; 20: 870-888
        • Tournier JD
        • Smith R
        • Raffelt D
        • et al.
        MRtrix3: a fast, flexible and open software framework for medical image processing and visualisation.
        Neuroimage. 2019; 202116137
        • Zamani A
        • O'Brien TJ
        • Kershaw J
        • Johnston LA
        • Semple BD
        • Wright DK.
        White matter changes following experimental pediatric traumatic brain injury: an advanced diffusion-weighted imaging investigation.
        Brain Imaging Behav. 2021; 15: 2766-2774
        • Rota M
        • Antolini L
        • Valsecchi MG.
        Optimal cut-point definition in biomarkers: the case of censored failure time outcome.
        BMC Med Res Methodol. 2015; 15: 24
        • Reyes J
        • Mitra B
        • Makdissi M
        • et al.
        Visible signs of concussion and cognitive screening in community sports.
        J Neurotrauma. 2022; 39: 122-130
        • Shultz SR
        • McDonald SJ
        • Corrigan F
        • et al.
        Clinical relevance of behavior testing in animal models of traumatic brain injury.
        J Neurotrauma. 2020; 37: 2381-2400
        • DeWitt DS
        • Hawkins BE
        • Dixon CE
        • et al.
        Pre-clinical testing of therapies for traumatic brain injury.
        J Neurotrauma. 2018; 35: 2737-2754
        • Weil ZM
        • Gaier KR
        • Karelina K.
        Injury timing alters metabolic, inflammatory and functional outcomes following repeated mild traumatic brain injury.
        Neurobiol Dis. 2014; 70: 108-116
        • Prins ML
        • Alexander D
        • Giza CC
        • Hovda DA.
        Repeated mild traumatic brain injury: mechanisms of cerebral vulnerability.
        J Neurotrauma. 2013; 30: 30-38
        • Longhi L
        • Saatman KE
        • Fujimoto S
        • et al.
        Temporal window of vulnerability to repetitive experimental concussive brain injury.
        Neurosurgery. 2005; 56 (discussion -74): 364-374
        • Grant DA
        • Serpa R
        • Moattari CR
        • et al.
        Repeat mild traumatic brain injury in adolescent rats increases subsequent beta-amyloid pathogenesis.
        J Neurotrauma. 2018; 35: 94-104