Recent studies have linked the consumption of caffeine to lower risks of developing Alzheimer's disease in addition to a slowing of cognitive decline, but the mechanism behind such effects has so far eluded scientists.
Now a team of US researchers have produced data that could suggest an answer – offering an insight into why caffeine could be reducing the risk of dementia related diseases such as Alzheimer’s.
"We have discovered a novel signal that activates the brain-based inflammation associated with neurodegenerative diseases, and caffeine appears to block its activity,” explained Professor Gregory Freund from the University of Illinois – who led the research.
Writing in the Journal of Neuroscience, Freund and his colleagues examined the effects of caffeine on memory formation in two groups of mice – one group given caffeine, the other receiving none.
The team found that mice given caffeine had lower inflammatory markers and recovered the ability to form memories after hypoxia 33% faster than those not given caffeine.
The research team exposed both groups of rats to hypoxia (a reduction in oxygen to the body) in order to simulate what happens in the brain during an interruption of breathing or blood flow. Hypoxia also causes cognitive and learning issues.
"It's not surprising that the insult to the brain that the mice experienced would cause learning memory to be impaired," said Freund.
He explained that that the hypoxic episode triggered the release of adenosine by brain cells – which causes a risk to other cells in the area by activating caspase-1 enzymes. This in turn triggers production of the cytokine IL-1β, a critical player in inflammation, said Freund.
The researchers revealed that the caffeine also had anti-inflammatory effect by blocking signalling of interleukin-1 – a critical player in the inflammation associated with many neurodegenerative diseases.
"Caffeine blocks all the activity of adenosine and inhibits caspase-1 and the inflammation that comes with it, limiting damage to the brain and protecting it from further injury."
Source: The Journal of Neuroscience
Volume 32, Issue 40, Pages 13945-13955, doi: 10.1523/JNEUROSCI.0704-12.2012
“Hypoxia/Reoxygenation Impairs Memory Formation via Adenosine-Dependent Activation of Caspase”
Authors: Gabriel S. Chiu, Diptaman Chatterjee, Patrick T. Darmody, John P. Walsh, Daryl D. Meling, et al