Blood-Based Biomarkers Can Detect Alzheimer’s 10 Years Before Disease Onset

A new study conducted by researchers at Karolinska Institutet on an inherited form of Alzheimer’s shows that a protein called glial fibrillary acidic protein (GFAP) is a possible biomarker for very early stages of the disease, which could one day lead to an earlier detection of this serious and common disease.

For the study, the researchers analyzed 164 blood plasma samples from 33 mutation carriers and 42 relatives without the inherited pathogenic predisposition. The data were collected between 1994 and 2018. Results reveal clear changes of several blood protein concentrations in the mutation-carriers. “The first change we observed was an increase in GFAP approximately 10 years before the first disease symptoms,” says the study’s last author Caroline Graff, professor at the department of neurobiology, care sciences and society at Karolinska Institutet. “This was followed by increased concentrations of P-tau181 and, later, NfL (neurofilament light protein), which we already know is directly associated with the extent of neuronal damage in the Alzheimer’s brain. This finding about GFAP improves the chances of early diagnosis.”

“Our results suggest that GFAP, a presumed biomarker for activated immune cells in the brain, reflects changes in the brain due to Alzheimer’s disease that occur before the accumulation of tau protein and measurable neuronal damage,” says the study’s first author Charlotte Johansson, doctoral student in the same department at Karolinska Institutet. “In the future, it could be used as a noninvasive biomarker for the early activation of immune cells such as astrocytes in the central nervous system, which can be valuable to the development of new drugs and to the diagnostics of cognitive diseases.”