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Stress worsens stroke outcome by affecting gene expression
Edward R. Winstead

Recovery from stroke was impaired by living in a stressful environment prior to the stroke, a study in mice found. The researchers attribute this to the impact of stress on the expression of a gene that switches on in response to brain injuries, the bcl-2 protooncogene. Expression of bcl-2 is associated with the survival of cells in various human neurodegenerative disorders, including stroke.

By affecting bcl-2 expression, psychological stress may compromise one of the brain's survival mechanisms following injury. Stressed mice had 70 percent less stroke-induced bcl-2 expression and fared worse following the stroke than controls.

In a second finding, transgenic mice that express extra bcl-2 had positive outcomes despite experiencing the stressful pre-stroke environment. Preserving the expression of bcl-2 may provide a buffer against exacerbation of stroke injury due to stress. The findings appear in Proceedings of the National Academy of Sciences.

The study, led by A. Courtney DeVries of Johns Hopkins University School of Medicine in Baltimore, involved creating a stressful pre-stroke "social milieu" for the mice. Individual mice were placed in the home cage of a large aggressive mouse for periods of time prior to receiving an induced, controlled stroke.

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DeVries, A.C. et al. Social stress exacerbates stroke outcome by suppressing Bcl-2 expression. Proc Natl Acad Sci USA 98, 11824-11828 (September 25, 2001).

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