Study reveals how tau tangles spread from one brain region to another in Alzheimer's

Alzheimer's disease is a progressive neurodegenerative disorder that slowly impairs memory, affects thinking skills, and eventually interferes with daily functioning. It is the most common cause of dementia, which affects millions of families around the world and places a vast emotional and economic toll on families.

In Alzheimer's disease, two key proteins, extracellular amyloid-beta plaques and an intercellular protein called tau, disrupt communication between the brain's cells and lead to cell damage and death. As tau becomes abnormal it forms neurofibrillary tangles and spreads through critical regions of the brain, triggering cell death and the cognitive decline characteristic of Alzheimer's disease.

A study published in Neuron led by researchers at the University of Alabama at Birmingham, Rush University Medical Center in Chicago, Illinois, and SUNY Upstate Medical Center in Syracuse, New York, provides new insight into a fundamental mystery of Alzheimer's disease: how tau tangles spread from one brain region to another. The findings of the study introduce evidence that targeting tau as it spreads can offer a viable path to slowing or preventing the advancement of Alzheimer's disease.

Tau is a microtubule-associated protein that is found inside the brain's neurons that helps support their internal structure by serving as a "scaffolding." In people with Alzheimer's disease, however, tau proteins begin sticking together inside cells. These tangles clump together and impair neural function, which eventually kills the cells. The more that tau spreads, the more memory loss that occurs. What remained unclear was the mechanism by which tau travels through the brain's network.