Cambridge scientists have investigated the spread of the toxic tau protein in Alzheimer’s disease and a rare brain disease called progressive supranuclear palsy (PSP). Published in the scientific journal, BRAIN, the study suggests that there are key differences in the way the protein builds up in the two diseases, shedding new light on how both diseases develop.
A total of 17 participants with Alzheimer’s disease, 17 with PSP, and a further 12 healthy volunteers took part in the study. Researchers used brain scans called PET scans to assess the build-up of tau protein in the brains of each participant and MRI scans to see how this build-up related to complex networks of interconnected nerve cells in brain.
The researchers found that in Alzheimer’s disease, tau protein built up in nerve cells that were strongly connected and constantly communicating with each other, whereas in PSP the protein appeared in nerve cells that used the most energy, regardless of any direct connection. The scientists suggest that this difference reflects different processes underlying the spread of tau in the two different conditions.
Dr Carol Routledge, Director of Research at Alzheimer’s Research UK, said:
“Stopping or slowing the progression of diseases like Alzheimer’s is a key goal in dementia research and to have the best chance of success, we need to understand more about how toxic proteins spread through the brain and exert their effects.
“This important study sheds new light on how the tau protein spreads through nerve cells to damage more and more of the brain over time. The observation that tau spreads differently in Alzheimer’s to another tau-related brain disease is interesting and could now allow researchers to investigate more targeted approaches for blocking the spread of the protein in each disease.
“While this study adds another piece to the puzzle, it doesn’t conclusively solve the crucial question of exactly how tau spreads through the brain. While the researchers used cutting-edge brain scanning techniques, they weren’t able to reveal all the forms of tau protein that could be playing a role in Alzheimer’s. This study gave a snapshot of the brain at one point in time, but future research can now use this innovative approach to build a more complete picture of how these diseases progress over time.”