Detecting Alzheimer’s even before it shows symptoms with a simple blood test is possible. The reason is that the brain protein GFAP, glial fibrillar acidic protein, is increased in people who suffer from the disease, even those who do not yet have symptoms and can be observed in the blood plasma.
The discovery of this biomarker is the work of a team of researchers belonging to the research center of the Pasqual Maragall Foundation, the Barcelonaβeta Brain Research Center (BBRC) and opens the door to being able to take measures against the disease much earlier , in addition to being a test non-invasive diagnostic.
“What we have shown is that the measurement of a protein called GFAP, which is expressed in brain cells called astroglia, is increased in the blood of patients with Alzheimer’s disease, but not only patients who already have the symptoms developed of the disease, but also in people in the preclinical phase , long before the disease begins ”, explains Marc Suárez-Calvet, principal investigator of the study and head of the group of Biomarkers in Fluids and Translational Neurology at BBRC.
The results of the experiment have been validated in about 900 people belonging to three independent international cohorts. First, the scientists analyzed the blood samples of 387 people without cognitive alterations and with a certain risk of developing Alzheimer’s, from the Alfa Study (Pasqual Maragall Foundation and ‘la Caixa Foundation). They then investigated the plasma of 300 asymptomatic and cognitively impaired people who are part of the TRIAD study, from McGill University in Montreal. And, finally, they analyzed the samples of 187 patients with cognitive impairment from the Lariboisière Hospital in Paris.
GFAP, for its acronym in English, is a brain protein specific to the cells of the astroglia. These cells are responsible for supporting the activity of neurons and help regulate the blood-brain barrier, which prevents the entry of bacteria and other substances into the brain. If brain damage occurs, these cells react, in a process known as astrogliosis. Astrogliosis tries to contain the damage, increasing the expression of GFAP and other markers.
In the specific case of Alzheimer’s, GFAP is usually measured in the cerebrospinal fluid by means of a lumbar puncture. The advantage of the new discovery is that it can also be measured in blood, in a less invasive and more precise way , providing information on where the person is in the disease. “We have seen that the levels of the biomarker GFAP are higher in people who are in the asymptomatic phase of Alzheimer’s, and that they allow us to differentiate between individuals with or without amyloid pathology in the brain, which is the stage prior to the disease” , explains Marta Milà-Alomà, researcher of the study and member of the group of Biomarkers in Fluids and Translational Neurology of the BBRC.
The results of this international study add to the latest findings of blood biomarkers to detect Alzheimer’s disease. In November 2020, the same team led by Suárez-Calvet at the BBRC identified other biomarkers, in this case the tau protein , to detect the initial stages of the disease. “In just two years, research in the field of Alzheimer’s biomarkers in the blood is advancing at such a rate that we are convinced that in the near future we will be able to detect the silent changes that occur in the brain with a simple requested blood test. by the GP. This will allow us to test treatment before neuronal damage is irreversible ”.
Referencia: Benedet AL, Milà-Alomà M, Vrillon A, et al. Differences Between Plasma and Cerebrospinal Fluid Glial Fibrillary Acidic Protein Levels Across the Alzheimer Disease Continuum. JAMA Neurol. Published online October 18, 2021. doi:10.1001/jamaneurol.2021.3671
