Highlights in traumatic brain injury research in 2021

Abstract

Several advances have been made in traumatic brain injury (TBI) research in 2021, further progressing our understanding of this complex condition and its treatment. In particular, considerable efforts are underway to identify biomarkers that can predict neuropathology and outcome. For instance, axonal injury is a hallmark pathology after TBI and a strong predictor of clinical outcome. However, the field does not have the methods to quantify the extent of axonal damage in a clinical setting. In their breakthrough multicentre, cross-species study, Graham and colleagues 1 Graham NSN Zimmerman KA Moro F et al. Axonal marker neurofilament light predicts long-term outcomes and progressive neurodegeneration after traumatic brain injury. Sci Transl Med. 2021; 13eabg9922 Crossref PubMed Scopus (1) Google Scholar validated neurofilament light (NfL) as a fluid biomarker of axonal damage after moderate-to-severe TBI. They showed that plasma concentrations of NfL are increased after TBI, peaking between 10 days and 6 weeks after injury in humans. NfL concentrations are, in turn, associated with MRI-derived markers of axonal injury and predict white matter neurodegeneration and functional outcomes at 6 and 12 months. Graham and colleagues validated their findings in an experimental model of cortical impact, via which they found a correlation between histopathologically defined axonal damage and NfL concentration. This study supports the use of NfL in the subacute period after TBI to measure axonal injury and predict functional outcome.