Blood biomarkers detect reduced brain structure volume associated with repetitive head impacts in professional boxers and MMA fighters
By Lillian Lee. This article was initially published in our Concussion Update newsletter; please consider subscribing.
A recent study discussed in Neurology Advisor found that for active and retired professional fighters exposed to repetitive head impacts (RHI), blood plasma measurements of the biomarkers glial fibrillary acidic protein (GFAP) and neurofilament light chain (NfL) “may help identify those who are at risk for progressive regional brain atrophy and cognitive decline.” While further longitudinal studies over a longer time and with varying cohorts of participants are needed, plasma GFAP levels may one day be used as a longitudinal measure to help identify those with an increased likelihood of showing cognitive decline and may one day be used to assess patient condition in clinical trials. Similarly, this study from Bernick et al., published in Alzheimer’s Research & Therapy, found that NfL measurements could be used to help identify neural injury in those actively exposed to RHI.
There is limited information on the effectiveness of fluid biomarkers in identifying neurodegenerative processes among individuals with RHI exposure. This study explores the relationship between four distinct blood biomarkers––p-tau231, N-terminal tau, GFAP, and NfL––and longitudinal change in cognitive function. The study’s 472 participants consisted of a sample of active and retired professional fighters as well as a control group with no known neurological disorders or previous head trauma. Athletes were recruited from the Professional Athletes Brain Health Study (PABHS), a longitudinal cohort of boxers and mixed martial arts (MMA) fighters.
Researchers also measured changes in MRI regional volumes in relation to changes in blood biomarkers. Among members of the active fighter cohort, heightened GFAP measurements were correlated with lower corpus callosum and thalamic volumes as well as worsening scores on psychomotor speed. Retired boxers with higher GFAP levels showed reduced volume in specific brain structures and worsened cognitive performance. In this cohort (retired boxers), there was an observed decrease in total brain volume, notably in gray matter. While these results are promising for the use of GFAP and NfL measurements as potential assessment tools, the findings of this study may be limited due to the longitudinal design and the non-random sampling of PABHS participants.
