In a new study published in Molecular Psychiatry, researchers have measured how deposits of the pathological protein tau spread through the brain over the course of Alzheimer’s disease. Their results show that the size of the deposit and the speed of its spread differ from one individual to the next, and that large amounts of tau in the brain can be linked to episodic memory impairment.

Even in a very early phase of Alzheimer’s disease there is an accumulation of tau in the brain cells, where its adverse effect on cell function causes memory impairment. It is therefore an attractive target for vaccine researchers. For the present study, the research team used PET brain imaging to measure the spread of tau deposits as well as the amyloid plaque associated with Alzheimer’s disease, and charted the energy metabolism of the brain cells. They then examined how these three parameters changed over the course of the disease.

The study included 16 patients at different stages of Alzheimer’s disease. The patients were given a series of neurological memory tests and underwent PET scans at 17-month intervals. While all 16 participants had abundant amyloid plaque deposition in the brain, the size and speed of spread of their tau deposits differed significantly between individuals. A notable correlation between the size of the deposit and episodic memory impairment was also found, the researchers said, noting that this could explain differences in disease progression across patients.

Paper: “Longitudinal changes of tau PET imaging in relation to hypometabolism in prodromal and Alzheimer’s disease dementia”
Reprinted from materials provided by Karolinska Institutet.

juillet 25, 2017