Stress and certain medications appear to rapidly exacerbate the formation of brain lesions that are the hallmarks of Alzheimer’s disease, according to researchers at the University of California, Irvine.
In a study with genetically modified mice, Frank LaFerla and a team of researchers found that when young animals were injected for just 7 days with dexamethasone, a glucocorticoid similar to the body’s stress hormones, the levels of the protein beta-amyloid in the brain jumped by 60%. When beta-amyloid production increases and these protein fragments aggregate, they form plaques, one of the two hallmark brain lesions of Alzheimer’s disease.
The scientists also found that the levels of another protein, tau, also increased. Tau accumulation eventually leads to the formation of tangles, the other signature lesion of Alzheimer’s.
“It is remarkable that these stress hormones can have such a significant effect in such a short period of time,” LaFerla comments. “Although we have known for some time that higher levels of stress hormones are seen in individuals in the early stages of Alzheimer’s, this is the first time we have seen how these hormones play such a direct role in exacerbating the underlying pathology of the disease.”
“This study suggests that not only is stress management an important factor in treating Alzheimer’s disease, but that physicians should pay close attention to the pharmaceutical products they prescribe for their elderly patients,” warns co-author Kim Green. “Some medications prescribed for the elderly for various conditions contain glucocorticoids. These drugs may be leading to accelerated cognitive decline in patients in the early stages of Alzheimer’s.”
Journal of Neuroscience – August 2006;26:9047-56.