In a new study from Trinity College Dublin, researchers found that secondary infections and new inflammatory events amplify the brain’s immune response and affect memory, even when these secondary events occur outside the brain.
Secondary infection is an infection that occurs during or after treatment for another infection.
Scientists believe that key brain cells (astrocytes and microglia) are already in an active state due to inflammation caused by Alzheimer’s disease (AD).
This study shows that secondary infections can then trigger an over-the-top response in those cells, which has knock-on effects on brain rhythms and on cognition.
In the study, the team found mice engineered to show features of AD and exposed to acute inflammatory events had brain inflammation and impaired memory.
These new cognitive changes are similar to acute and distressing psychiatric disturbances like delirium, which frequently occur in elderly patients.
Although it is difficult to replicate these findings in patients, the study additionally showed that AD patients who died with acute systemic infection showed heightened brain levels of IL-1β.
This is a pro-inflammatory molecule that was important in causing the heightened immune response and the new-onset disruptions seen in the AD mice.
The team says that these hypersensitive responses may contribute to the negative outcomes that follow acute illness in older patients.
This includes episodes of delirium and the accelerated cognitive trajectory that has been observed in patients who experience delirium before or during their dementia.
Alzheimer’s disease is the most common form of dementia, affecting more than 5% of those over 60 and this distressing, debilitating condition causes difficulties for a huge number of people across the globe.
If you care about Alzheimer’s and dementia, please read studies about this drug may help treat Lewy body dementia and findings of a new method for an effective prevention of Alzheimer’s disease.
For more information about Alzheimer’s and dementia prevention and treatment, please see recent studies about this blood pressure problem may increase Alzheimer’s disease risk and results showing that if your left and right-brain age differently, you are more likely to have Alzheimer’s disease.
The study is published in Alzheimer’s & Dementia. One author of the study is Colm Cunningham.
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