Blood GFAP a sensitive biomarker for early Alzheimer’s disease

Reuters Health - 18/10/2021 - Blood levels of glial fibrillary acidic protein (GFAP) are a sensitive biomarker for amyloid-beta pathology in the early stages of Alzheimer's disease (AD) and significantly outperform cerebrospinal fluid (CSF) levels of the protein, new research suggests.

"Plasma GFAP, alone or in combination with other biomarkers, could be used to screen for amyloid-beta-positive individuals at any stage across the AD continuum," the researchers say in JAMA Neurology.

GFAP is a marker of reactive astrogliosis that increases in CSF and blood of people with AD. However, whether there are differences in blood GFAP levels across the entire AD continuum and whether its performance is similar to that of CSF GFAP has been unknown, Dr. Kaj Blennow of the University of Gothenburg, in Sweden, and colleagues note in their paper.

The researchers evaluated the levels of plasma GFAP throughout the AD continuum and compared them with the levels of CSF GFAP.

Participants included 300 adults (mean age, 65 years; 177 women) from Montreal, Canada, enrolled in the Translational Biomarkers in Aging and Dementia (TRIAD) cohort; 384 adults (mean age, 61 years; 234 women) from Barcelona, Spain, participating in the Alzheimer's and Families (ALFA+) study and 187 adults (mean age, 70 years; 116 women) from Paris in the BioCogBank Paris Lariboisiere cohort.

They found that plasma GFAP levels were elevated in the preclinical and symptomatic stages of AD, with levels higher than those of CSF GFAP.

They also found that plasma GFAP was more accurate than CSF GFAP in discriminating between amyloid-beta-positive and amyloid-beta-negative individuals, also at the preclinical stage.

"Therefore, plasma GFAP levels appear to be a superior biomarker tracking amyloid-beta pathology than its CSF counterpart," the researchers say.

"This finding is particularly evident for individuals with preclinical AD; plasma GFAP levels were significantly higher in cognitively unimpaired amyloid-beta-positive (CU+) individuals and significantly discriminated them from cognitively unimpaired amyloid-beta-negative (CU-) individuals, whereas CSF did not," they note.

SOURCE: https://bit.ly/3DVJE2D JAMA Neurology, online October 18, 2021.

By Reuters Staff



Posted on 18 October, 202126 October, 2021