Glial Fibrillary Acidic Protein as a Marker for Mild Traumatic Brain Injury

What's the science?

Millions of cases of mild traumatic brain injury occur each year. Computed tomography (CT) scans are used to detect mild traumatic brain injury, and MRI can be used to detect subtle changes in the brain like neuron axonal injury, however these are costly and time-consuming. There is a need for a blood-based biomarker that can detect milder forms of brain injury to ensure proper treatment for these patients. This week in Neurology, Ori and colleagues test whether blood-based biomarkers are associated with neuroimaging changes (on CT and MRI scans) and can successfully detect mild traumatic brain injury. 

How did they do it?

Four blood-based biomarkers have previously been associated with brain changes that follow traumatic brain injury of varying severities: Tau (a neuronal injury marker), Glial Fibrillary Acidic protein, ubiquitin carboxyl-terminal hydrolase L1 (UCH-L1) and neurofilament light. The authors aimed to assess whether any of these biomarkers would be elevated in mild traumatic brain injury and whether they were also associated with subtle structural changes shown on an MRI scan (using diffusion tensor imaging). A group of 277 patients seeking care for a mild brain injury were enrolled in the study. Blood was drawn to measure plasma concentrations of biomarkers and CT and MRI scans were performed within 48 hours of the injury. A control group of 49 healthy participants (with well-matched demographics) was included for comparison.

What did they find?

Glial Fibrillary Acidic protein, Tau and Neurofilament light were all higher in patients with mild traumatic brain injury compared to controls. Glial Fibrillary Acidic protein was the best predictor of mild traumatic brain injury (diagnosis). When patients with mild brain injury were stratified into those with and without changes on their CT scans, Glial Fibrillary Acidic protein, Tau and neurofilament light concentrations were all higher in patients with detectable changes. However, Glial Fibrillary Acidic protein concentration was the only biomarker that significantly predicted trauma-related CT scan changes. Glial Fibrillary Acidic protein, Tau and Neurofilament light all predicted structural MRI changes, however Glial Fibrillary Acidic protein was the strongest predictor of structural MRI changes related to mile traumatic brain injury.

What's the impact?

This is the first study to examine whether blood-based biomarkers can be used to detect mild traumatic brain injury. Glial Fibrillary Acidic protein concentration is a sensitive predictor of mild traumatic brain injury and is also closely associated with neuroimaging changes. CT and MRI scans are expensive and time-consuming, so having methods to detect the presence and severity of brain injury early on is important for proper and effective treatment.

Gill et al., Glial fibrillary acidic protein elevations relate to neuroimaging abnormalities acutely following a mild traumatic brain injury. Neurology (2018). Access the original scientific publication here.