In an international study published April 29, 2021 in Nature Medicine, researchers identified 4 distinct subtypes of Alzheimer’s disease. Indeed, the tau protein, responsible for Alzheimer’s disease, spreads according to four distinct patterns. A discovery that could pave the way for individualized treatments.
The tau protein responsible for Alzheimer’s spreads according to 4 distinct patterns
We know that Alzheimer’s disease is characterized by the abnormal accumulation of tau protein which results in the degradation of neurons. In a study published on April 29, 2021 in the journal Nature Medicine, an international team of researchers revealed that this tau protein spreads in four distinct patterns. To arrive at this observation, the scientists followed 1143 participants. Among them, some had not yet developed any symptoms (pre-symptomatic Alzheimer’s disease), some had mild memory impairment and others were people with fully developed Alzheimer’s dementia.
They then used an algorithm that sifted through the data from the PET (positron emission tomography, an advanced medical imaging) images and were able to distinguish four subtypes of the disease, which became distinct over time. time. Oskar Hansson, professor of neurology at Lund University and one of the study’s authors explains it this way: “ The prevalence of subgroups ranged between 18-30%, meaning that all of these Alzheimer’s disease variants are actually quite common and none dominate as we previously thought. “.
The 4 subtypes of Alzheimer’s disease
In the first observed subtype which represents 33% of cases, the researchers report that the tau protein propagates mainly in the temporal lobe and mainly affects memory. The second subtype that develops in 18% of cases, the tau protein spreads this time, to the rest of the cerebral cortex. In this setup, scientists report that those affected face difficulties with executive functions but have less memory problem. Regarding the third subtype, which represents 30% of cases, the tau protein is deployed in the visual cortex, resulting in difficulties in orientation and distinguishing distances and spaces. Finally, the fourth subtype, which develops in 19% of cases, results in the spread of the tau protein asymmetrically in the left hemisphere, which mainly affects the language abilities of the individual.
The results of the study and the discovery of these 4 distinct subtypes of Alzheimer’s disease could lead to the implementation of individualized treatments for affected patients. According to Jacob Vo-gel of McGill University, lead author of the study, “ This suggests that Alzheimer’s disease is an even more heterogeneous disease than previously thought. “. For Oskar Hansson, “ The discovery of these 4 distinct patterns of tau protein spread also leads us to wonder if the four subtypes might respond differently to different treatments. “.
