Study proves early detection of Alzheimer’s disease using blood test

Beyond a cure, which appears to be a long way off, the “holy grail” of Alzheimer’s disease research is a biomarker that predicts the early symptoms of this neurodegenerative disease, which is responsible for 60% to 80% of dementia cases. The largest study to date, conducted by Spanish researchers, has identified a biomarker that will allow early detection of this disease using a simple blood test. This was achieved by a research team led by the Ace Alzheimer’s Center in Barcelona in collaboration with the Sant Pau Hospital in the same city. The study was published in The Lancet’s journal eBioMedicine.

This biological snitch is the plasma biomarker pTau181, a protein that has been known for 20 years to be involved in the degenerative process of Alzheimer’s disease. The study was conducted in a memory clinic with a very large sample of over 2000 patients and lasted 8 years. According to the Ace Alzheimer’s Center in Barcelona, ​​the blood biomarker pTau181 has a sensitivity of 94% and an accuracy of close to 80% for identifying patients at high risk of developing Alzheimer’s disease in the early stages.

“Alzheimer’s disease is very difficult to detect in the early stages because when the patient begins to show the first clinical symptoms, the changes that have occurred in the brain have appeared 15 years earlier,” explains Amanda Cano, director of the biological center. Program “Molecular and Biomarkers” at the Alzheimer’s Center Ace in Barcelona and head of the research group. “Therefore,” he adds, “at this stage the patient does not have any sense of having a problem, and today we do not have any diagnostic or detection method that can solve this problem at these stages.”

The Tau181 protein serves to maintain the structure of neurons, but when changes occur in its structure, it stops functioning and tends to accumulate inside those nerve cells. “These aggregates cause a neurotoxic current typical of this disease,” the researcher emphasizes. Detecting levels of this protein means we can understand or visualize the occurrence of this pathology,” he adds.

Dr. Cano notes that biomarkers of Alzheimer’s disease are currently measured either by extracting cerebrospinal fluid through a lumbar puncture (an injection near the spinal cord, similar to an epidural), or through neuroimaging techniques, in which the patient is injected with a substance with a certain radioactive activity and then receives image of brain lesions. “Both interventions, lumbar puncture and neuroimaging techniques, are invasive for the patient and very expensive for the healthcare system; Today they are recommended only for very high suspicion of disease, they are not recommended in these early stages,” he says. Using this biomarker could reduce the need for lumbar punctures by 39%.

The clinical data they collected over more than 8 years from more than 2,000 patients served to compare this biomarker, which can be obtained non-invasively and is available in primary health care centers with a simple blood draw. This will speed up diagnosis at earlier and earlier stages, at which it is still possible to intervene and use new drugs such as Lekembi (lekanemab), which slows the progression of Alzheimer’s disease in the early stages.