Blood test to predict Alzheimer's years before clinical presentation | BioTechniqes

One of the main reasons why there is no effective treatment for Alzheimer's disease is that all treatments start too late. At the time of clinical symptoms, brain damage and irreversible neuronal loss have already been observed.

Diagnostic blood tests for the treatment of Alzheimer's disease have been successful, with emphasis on amyloid protein levels characteristic of the disease. However, the controversy regarding the true effect of amyloid and its exact role in neurodegeneration being unknown, this could also allow to detect the disease at a too late stage.

Researchers at the German Center for Neurodegenerative Diseases (DZNE, Bonn, Germany) have developed a new test, created from a different angle.

Once released after neuronal apoptosis, protein fragments from inside the cell enter the bloodstream where they have the potential to be detected.

"Normally, though, these proteins break down quickly in the blood and are therefore not very appropriate as markers of a neurodegenerative disease," continued Jucker. "One exception, however, is a small piece of neurofilament that is surprisingly resistant to this degradation."

With a blood test to detect this protein, the researchers discovered that the neurofilament could be found in the bloodstream at the preclinical stage of the disease, well before the onset of a memory deficiency and a pain. other clinical symptoms. The level of the protein in the blood reflects the stage of the disease and can predict its evolution.

Jucker and his colleagues used samples from an international research collaboration on the early development of Alzheimer's disease and its genetic and family foundations. The results, recently published in Nature Medicine, showed that changes in the blood were observable until 16 years before the onset of clinical symptoms. Changes in neurofilament concentration were able to accurately reflect neuronal damage and could predict brain loss and cognitive changes up to 2 years before onset.

The results also corroborate the opposition to the amyloid hypothesis, a lack of correlation between neurodegeneration and amyloid concentration suggests that these are independent events. This demonstrates that the presence of amyloid is perhaps not as causal as previously believed.

"The test accurately shows the evolution of the disease and therefore constitutes a powerful instrument for the study of new treatments for Alzheimer's disease in the context of clinical trials," concluded Jucker.