Stress may increase Alzheimer's risk

MUNICH, Germany, May 27 (UPI) -- Increased release of stress hormones leads to generation of abnormally phosphorylated tau protein and memory loss in rats, German researchers said.

Osborne Almeida of the Max Planck Institute of Psychiatry in Munich and colleagues at the University of Minho in Braga, Portugal, said protein deposits in nerve cells are a typical feature of Alzheimer's disease. A process known as hyperphosphorylation causes the protein in the cells to aggregate into clumps and as a result, nerve cells die, particularly in the hippocampus -- a part of the brain that plays an important role in learning and memory -- as well as in the prefrontal cortex that regulates higher cognitive functions, the researchers said.

The researchers showed stress and the hormones released during stress can accelerate the development of Alzheimer disease-like biochemical and behavioral pathology.

"Our findings show that stress hormones and stress can cause changes in the tau protein like those that arise in Alzheimer's disease," Almeida said in a statement.

The findings are published in the Journal of Neuroscience.