Glial fibrillary acidic protein may identify risk for brain atrophy, cognitive decline

Key takeaways:

• Researchers analyzed blood biomarker data from 420 active and retired athletes and 52 controls.
• Boxers had the highest level of blood biomarkers that indicate higher risk for cognitive decline.

For individuals exposed to athletic-related head contact, glial fibrillary acidic protein may help identify those who are at risk for progressive regional brain atrophy and cognitive decline, per data from Alzheimer’s Research & Therapy.

“Currently, researchers and clinicians have no way to determine who will develop a long-term neurological condition, and when, resulting from repetitive head impacts,” Charles Bernick, MD, MPH, staff neurologist at Cleveland Clinic Lou Ruvo Center for Brain Health, told Healio in an email. “We demonstrated a potential biomarker, measured through blood, which could one day be used to follow brain changes in individuals over time to intervene sooner.”

Bernick and colleagues sought to examine the relationship between blood biomarkers and longitudinal change in cognitive function and regional brain volumes in a cohort of professional fighters.

They analyzed data from 140 active boxers (mean age 31 years), 211 active mixed martial arts (MMA) fighters (mean age 30 years), 69 retired boxers (mean age 49 years) and 52 control subjects (mean age 36 years) with no prior history of head impacts.

At baseline, 3T MRI brain imaging, plasma samples, and computerized cognitive testing were obtained as well as annually for a subset of the study population. MRI regional volumes were extracted, along with plasma levels of neurofilament light chain (NfL), glial fibrillary acidic protein (GFAP), p-tau231, and N-terminal tau (NTA). Researchers performed several statistical analyses to assess the relationship between biomarker plasma levels and regional brain volumes and cognitive performance at baseline and longitudinally.

According to results, baseline GFAP levels were highest in the retired boxers (retired boxers vs. active MMA: P = .0191), whereas active boxers had higher levels of NfL (active boxers vs. MMA: P = .047). GFAP showed an increase longitudinally in retired boxers that was associated with decreasing volumes of multiple cortical and subcortical structures (eg, hippocampus: beta = 1.25, 95% CI, 1.65 to 0.85) and increase in lateral ventricle size (beta = 1.75, 95% CI, 1.46 to 2.04).

Data additionally showed performance on cognitive domains including memory, processing speed, psychomotor speed and reaction time declined over time with increasing GFAP (eg, processing speed: beta = 0.04, 95% CI, 0.07 to 0.02; reaction time: beta = 0.52, 95% CI, 0.28 to 0.76). Among active fighters, increasing levels of GFAP demonstrated correlation with lower thalamic (beta = 1.42, 95% CI, 2.34 to 0.49) and corpus callosum volumes, along with progressively lower scores measuring psychomotor speed (beta = 0.14, 95% CI, 0.01 to 0.27).

“Glial fibrillary acidic protein could become a much needed biomarker for neurodegenerative disease,” Bernick told Healio. “As the field works to validate traumatic encephalopathy syndrome, the current research diagnostic criteriaaimed atidentifyingwho may be more likely to developchronic traumatic encephalopathy GFAP could become a supportive feature.”