Individual Alzheimer’s prognosis based on the spread of tau
Alzheimer’s diseases can take very different courses. According to a recent study, one possible explanation for this is the individual spread of certain protein deposits in the brain.
A research team from the Ludwig Maximilians University of Munich (LMU) has examined the spread of misfolded tau proteins in the brains of Alzheimer’s patients and has thus shown possible explanations for the individual differences in the course of the disease. The method could also be used to predict the course of the individual disease. The study results were published in the journal “Science Advances”.
“Alzheimer’s dementia (AD) is one of the most common diseases of the central nervous system and is the main cause of dementia in old age,” reports the LMU Munich Hospital. An estimated 44 million people are affected worldwide. Although the causes of the disease have not yet been conclusively clarified, certain protein deposits are assessed as essential factors.
“In the course of AD, the misfolded proteins amyloid-beta and tau accumulate in the brain of those affected, which further destroys the nerve cells and the contact points between the neurons, the synapses,” said the LMU Clinic in Munich. The consequences are memory and orientation disorders, language disorders, disorders of the ability to think and judge as well as changes in personality. This makes coping with everyday life more and more difficult.
Tau proteins influence the course of the disease
Researchers at the Institute for Stroke and Dementia Research at the LMU Klinikum Munich recently demonstrated that the tau proteins mainly spread along networked brain regions during the course of the disease and play a decisive role in determining or worsening the course of the disease. The now published results of a follow-up study by the research team led by Professor Michael Ewers and first author Dr. Nicolai Franzmeier shows that this methodology also has the potential to predict the course.
Using brain imaging examinations using the so-called “tauPET” in two independent samples from 106 participants and 41 participants diagnosed with Alzheimer’s disease, the researchers examined the distribution of the pathologically altered tau proteins in the brain. The collected image data of the brain were linked to an atlas showing the connections between individual areas of the brain so that the brain regions could be identified that had accumulated the most tau at the time of the tau-PET.
Predicting the spread of tau protein in the brain
“These are the epicentres of tau pathology,” explains Dr. Franzmeier. In the further course it was shown that in the brain regions that are most strongly connected to these epicentres, about one to two years after the first tau-PET examination, there is also a high probability of abnormal tau being found. This methodology can be used to predict how the tau proteins will spread in the brain. “And that can be very different from person to person,” adds Professor Ewers.
Variability much greater than expected
Based on tissue examinations of the brains of deceased Alzheimer’s patients, the assumption has so far been that the disease process spreads relatively stereotypically for most of those affected via the same brain regions. The current study, however, comes to a different conclusion. “According to our data, the variability is much greater than assumed,” emphasizes Dr. Franzmeier.
For example, people with early tau in the right hemisphere were most likely to spread along connections in the right hemisphere, and vice versa in people with tau in the left hemisphere. “What this means clinically for the patients, what symptoms they develop as the disease progresses,” the researchers are now planning to find out in further studies, according to the LMU Clinic in Munich.
Not yet usable in everyday clinical practice
It can already be said that the new method “surpasses the previous methods of forecasting the spread of tau because it makes an individualized and patient-centered prognosis,” summarizes Dr. Franzmeier. However, up to now it has not been so precise that it could be used in everyday clinical practice in the short term, but it must first be further validated, adds Prof. Ewers.
Use for drug research
For clinical drug research, however, it can be used immediately and pharmaceutical companies researching active ingredients to prevent the spread of tau could benefit from this. “With our method, we can specifically predict where in the brain a drug to eliminate the tau pathology should actually work,” and it would be easier to determine whether an active ingredient is effective or not, says Ewers. (fp)
Author and source information
This text corresponds to the requirements of the medical literature, medical guidelines and current studies and has been checked by medical professionals.
Dipl. Geogr. Fabian Peters
- LMU Klinikum: On the way to an individual Alzheimer’s prognosis (published November 30, 2020), lmu-klinikum.de
- Nicolai Franzmeier, Anna Dewenter, Lukas Frontzkowski, eMartin Dichgans, Anna Rubinski, Julia Neitzel, Ruben Smith, Olof Strandberg, Rik Ossenkoppele, Katharina Buerger, Marco Duering, Oskar Hansson, Michael Ewers: Patient-centered connectivity-based prediction of tau pathology spread in Alzheimer’s disease; in Science Advances (veröffentlicht 25.11.2020), sciencemag.org
This article is for general guidance only and should not be used for self-diagnosis or self-treatment. He can not substitute a visit at the doctor.