The latest research on inflammation and Alzheimer's disease

Even though the immune system tends to work less effectively in older adults than in younger ones, the elderly are prone to low levels of immune response called inflammation. This seems to be due to overstimulation of the innate immune system, responsible for defending against unknown foreign invaders. Researchers have found that the elderly tend to have higher concentrations of inflammation-prompting cytokines than younger persons do.

Inflammation has been linked to a number of age-related diseases, including heart disease and Alzheimer's disease (AD). Lending weight to the link between AD and inflammation are numerous studies finding that regular consumption of non-steroidal anti-inflammatory drugs (NSAIDs) like ibuprofen (Advil) or naproxen (Aleve) is linked to a reduced risk of developing AD.

Only recently, however, have scientists found definitive proof that the AD-preventative effects of NSAIDs are due to their anti-inflammatory properties. In a study published in the August 2003 issue of the Journal of Neuroscience, researchers at Amgen, Inc., found that treating a mouse model of AD with ibuprofen resulted in a 60% reduction in the amount of beta-amyloid plaque in the cortex. Clumps of beta-amyloid plaque in the brain are one of the hallmarks of AD. The scientists established a link to inflammation with their finding that the ibuprofen also reduced the activation of microglia, small clumps of cells responsible for activating an inflammatory response to beta-amyloid in the brain.

Scientific evidence also shows that the use of statins, a popular class of drugs used to lower cholesterol, is also associated with a lower risk of AD. Recently, researchers working at Case Western Reserve University investigated the inflammation-fighting effects of statins. They found that statins reduced microglia-directed inflammation in neural cells via the same pathway that activates cholesterol production. However, adding cholesterol to the cells did not reverse the statins' anti-inflammatory effects, proving that the anti-inflammatory effects of statins are distinct from their cholesterol-lowering properties. Their work was published in the January 2005 issue of the Journal of Neuroscience.

Scientists hope that a better understanding of inflammation will lead to improved treatments for AD and other age-related diseases. For more information about inflammation and AD, see our Alzheimer's Disease Information Center.