A team of researchers, led by Robert A. Rissman of the University of California, San Diego School of Medicine, has learned that chronic, repeated stress leads to the formation of insoluble tau protein aggregates within the brain cells of mice, particularly within the hippocampus. These aggregates are similar to the neurofibrillary tangles that are characteristic of Alzheimer’s disease, supporting the hypothesis that there is a link between chronic stress and Alzheimer’s.
It does not appear that single, acute episodes of stress trigger the production of these aggregates; rather, such episodes may actually promote brain plasticity and the ability to learn. Instead, the researchers believe that chronic stress appears to result in pathological changes within the neuronal circuitry of the brain, and that these changes – perhaps together with the affects that aging may have on an individual’s neurons - may contribute to the development of Alzheimer’s disease.
It is hoped that these findings could contribute to the identification of agents that could mitigate the damaging effects of chronic stress. As noted by Rissman:
“The idea is to use an antagonist molecule to reduce the effects of stress upon neurons. The stress system can still respond, but the response in the brain and hippocampus would be toned down so that it doesn’t result in harmful, permanent damage.”