A simple blood test could help detect Alzheimer’s disease a decade before any symptoms appear, scientists suggest.
Researchers at the Karolinska Institutet in Sweden have discovered that a protein called GFAP could be used as a possible ‘blood marker’ in people who are in the very early stages of the disease.
The scientists said their findings, published in the journal Brain, could lead to earlier detection of the disease and help slow it down with drugs.
Charlotte Johansson, a doctoral student at the Department of Neurobiology, Care Sciences and Society at the Karolinska Institutet, first author of the study, explained: “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.”
What is Alzheimer’s?
Alzheimer’s disease is a progressive condition with symptoms developing gradually over many years and eventually becoming more severe. Nerve cells in the brain degenerate as a result of the abnormal accumulation of two types of proteins known as beta-amyloid and tau.
The first sign of the disease is usually minor memory problems. As more nerve cells become damaged, speech becomes affected. In the vast majority of cases – more than 99 in 100 – Alzheimer’s is not inherited, but in rarer types, there may be a strong genetic link.
In these cases, people with a parent with Alzheimer’s caused by a mutation have a 50% risk of developing the disease themselves.
For their study, the researchers analysed 164 blood plasma samples from 33 mutation carriers and 42 relatives without it and said the results showed “clear changes” in the samples of those who carried the mutations.
Caroline Graff, professor at the Department of Neurobiology, Care Sciences and Society at the Karolinska Institutet, and one of the study authors, said: “The first change we observed was an increase in GFAP (glial fibrillary acidic protein) approximately 10 years before the first disease symptoms.
“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.”