Recent advances in brain imaging have enabled scientists to show for the first time that tau protein, which causes nerve cell death, spreads throughout the brain in Alzheimer’s disease. This discovery is an important one, and suggests that preventing tau spreading could limit the damages caused by Alzheimer’s.

Scientists have been aware for years that Alzheimer’s disease is caused by the build-up in the brain of two abnormal proteins: amyloid beta and tau. They hypothesized that amyloid beta was first accumulated in the brain, leading at some point to the spread of tau protein, and to neuronal death.

Recent developments in positron emission tomography (PET) scanning have enabled scientists from University of Cambridge to image the build-up of tau proteins in patients. They published their results last week in the journal Brain.

The team described how patterns of tau relate to the wiring of the brains of 17 patients with Alzheimer’s disease, compared to controls. Their findings suggest that the protein spreads through the brain in a way that was hypothesized by scientists under the “transneuronal spreading” model.

Like an infection

This model suggests that harmful tau starts in one place and then spreads to other regions, setting off a chain reaction has in a flu epidemic, for example.

Confirmation of the transneuronal spread hypothesis is important because it suggests that we might slow down or halt the progression of Alzheimer's disease by developing drugs to stop tau from moving along neurons.

Further studies will need to confirm this discovery. Not only did the scientists used a small sample of patients in their studies, but they also did not follow them across time to confirm how tau was spreading. Still, this study is the first one to replicate what had been previously shown in a mouse model.

With the help of ScienceDaily

Additional sources

Science article talking about the discovery

Original article in Brain