Worldwide there are around 50 million people with some type of dementia –900,000 in Spain–, most of them with Alzheimer’s disease, and every three seconds a new case is diagnosed. With the increase in life expectancy, the number of cases could triple in 2050 and become a pandemic, as pointed out by the latest World Alzheimer Report 2018 published by Alzheimer’s Disease International.
For this reason, it is urgent to find diagnostic methods for Alzheimer’s that can detect the disease in its early stages, as well as effective treatments to slow down its progress and delay the subsequent cognitive deterioration. New research led by Spanish scientists has now found two new biomarkers –p-tau231 and p-tau217– whose measurement in blood allows the detection of brain changes related to the accumulation of amyloid beta protein in people without cognitive symptoms.
The study has been led by the Barcelonaβeta Brain Research Center (BBRC), a research center of the Pasqual Maragall Foundation, the Hospital del Mar Medical Research Institute (IMIM-Hospital del Mar) and the University of Gothenburg, and its results have been published in the prestigious scientific journal Nature Medicine.
A non-invasive test to identify people at risk of Alzheimer’s
The analysis of biomarkers in blood is an inexpensive and non-invasive test that has great potential to help diagnose Alzheimer’s, and therefore the objective of the study has been to carry out an exhaustive comparison between different biomarkers, since their choice could vary depending on the type of test to be performed.
The researchers have analyzed data from almost 400 participants in the ALFA+ Study and their results show that p-tau231 is a particularly suitable blood biomarker for capturing incipient brain changes associated with amyloid protein, before the plaque of this protein manifests itself and that Therefore, it would help to identify early middle-aged people who have a high risk of developing Alzheimer’s and to carry out clinical trials focused on this initial stage of the disease.
P-tau231 is an ideal blood biomarker for capturing brain changes associated with amyloid protein and could help identify early middle-aged people with a high risk of Alzheimer’s
The researchers developed the new blood biomarker p-tau231 in collaboration with the University of Gothenburg and compared it with five other blood biomarkers (p-tau181, p-tau217, Aß42/40, GFAP and NfL) that had been previously studied in the phase in which the symptoms of Alzheimer’s were already manifesting. This is the first study that analyzes all these biomarkers in the preclinical phase of this dementia.
The results of the work reveal that p-tau231 and p-tau217 are the best biomarkers in blood to detect the first signs of amyloid accumulation in the brain. The researchers have also shown that higher blood p-tau231 levels predict greater amyloid accumulation and loss of cognitive function at three-year follow-up.
The study authors note that the use of blood biomarkers may also facilitate clinical trials to prevent Alzheimer’s. “Biomarkers are a very useful tool that could accelerate the development of new treatments aimed at Alzheimer’s disease”, comments Marc Suárez-Calvet, head of the Fluid Biomarkers and Translational Neurology Group at the Barcelonaβeta Brain Research Center (BBRC) and researcher of the IMIM-Hospital del Mar. “Thanks to them, the recruitment time of participants in clinical trials on the early stage of this disease could be reduced, and the level of participation of more diverse populations would increase,” he adds.
They have verified that all plasma biomarkers are altered in the preclinical phase of Alzheimer’s, but have found significant differences between them. “In the ALFA+ cohort, all plasma biomarkers tested (p-tau181, p-tau217, p-tau231, GFAP, NfL and Aß42/40) were significantly altered in preclinical Alzheimer’s”, explains Marta Milà-Alomà, first author of the study and member of the Group of Biomarkers in Fluids and Translational Neurology. “However, plasma p-tau231 reached abnormal levels with the lowest amyloid load,” she notes.
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