The brains of people who develop Alzheimer’s begin to deteriorate decades before the first symptoms of the disease, such as memory loss, appear, and early detection of this type of dementia would allow early intervention that could help slow the deterioration. cognitive and improve the quality of life of patients and their families and caregivers.
Scientists are looking for more effective treatment options, but they are also studying how to design minimally invasive diagnostic tests that identify patients who have not yet experienced Alzheimer’s symptoms or have mild symptoms. Biomarkers in the blood are one of the study objectives and some have already been found, such as the plasma protein ptau181, which Spanish researchers have linked to the presence of Alzheimer’s, even in patients with few symptoms.
New research on an inherited form of Alzheimer’s has now shown that a protein called GFAP is a possible biomarker for very early stages of the disease. The study has been carried out by researchers from the Karolinska Institute (Sweden) and could contribute to earlier detection of this neurodegenerative disease.
“Our results suggest that GFAP reflects changes in the brain due to Alzheimer’s disease, which occur before tau protein accumulation and measurable neuronal damage.”
In Alzheimer’s disease there is a pathological accumulation of the proteins beta-amyloid and tau which causes the degeneration of nerve cells in the brain. The progressive damage of more and more brain neurons is manifested by the loss of cognitive functions such as memory and speech. Biological changes in the brain begin 20 to 25 years before a person shows obvious signs of memory loss and other cognitive problems, and the sooner Alzheimer’s is diagnosed, the sooner the patient can be given appropriate treatment.
Early diagnosis of Alzheimer’s and other cognitive diseases
“Our results suggest that GFAP, a putative biomarker of activated immune cells in the brain, reflects changes in the brain due to Alzheimer’s disease that occur before tau protein accumulation and measurable neuronal damage,” said Charlotte Johansson, PhD. student at the Department of Neurobiology, Care Sciences and Society at the Karolinska Institutet and first author of the study, which has been published in the journal Brain.
“In the future it could be used as a non-invasive biomarker for the early activation of immune cells such as astrocytes in the central nervous system, which may be valuable for the development of new drugs and for the diagnosis of cognitive diseases.”
Scientists at the Karolinska Institutet and Landspitali University Hospital in Iceland, the University of Gothenburg and University College London in the UK have been studying biomarkers in the blood to identify very early pathological changes in a rare, inherited form of Alzheimer’s that accounts for less than 1 % of all cases. People with a parent with Alzheimer’s disease caused by a mutation have a 50% risk of developing the disease themselves.
The researchers analyzed 164 blood plasma samples from 33 mutation carriers and 42 relatives of mutation carriers who had not inherited this pathogenic predisposition. The data was collected between 1994 and 2018, and the study results reveal clear changes of various blood protein concentrations in the mutation carriers.
“The first change we observed was an increase in GFAP (glial fibrillary acidic protein) approximately 10 years before the first symptoms of the disease,” explained the study’s last author, Caroline Graff, professor in the Department of Neurobiology, Care Sciences. and Karolinska Institute Society. “This was followed by higher 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 an early diagnosis,” she concludes.
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