Researchers have found that stroke victims develop higher risk for Alzheimer's disease because of gradual build-up of toxic chemicals due to reduced oxygen to the brain caused by the stroke.
The study was conducted by a team of researchers led by Chris Peers at the University of Leeds.
When the brain is functioning normally, it makes connections through the release of tiny amounts of chemical across the synapses. Once the chemical has been transmitted, it is 'mopped up' by the brain cells, called astrocytes.
As part of the study, researchers focussed on the damage done by low-oxygen incidents to the astrocytes.
"Our research is looking into what happens when oxygen levels in the brain are reduced by a number of factors, from long-term conditions like emphysema and angina, to sudden incidents such as a heart attack, stroke or even head trauma. Even though the patient may outwardly recover, the hidden cell damage may be irreversible," Peers said.
"It could even be an issue for people who snore heavily, whose sleep patterns are such that there will be times in the night when their brain is hypoxic - deprived of sufficient oxygen. It can be anything that stops the heart and lungs working together to their optimal capabilities," Peers added.
Researchers found that if at some point the astrocytes become hypoxic, they are less able to mop up these transmitters, allowing the residual chemicals to accumulate and become toxic.
The team is further investigating two key signalling molecules, which are very sensitive to fluctuations in oxygen levels. The scientists suspect that in low oxygen conditions these molecules could begin the increased production of a toxic protein called amyloid which builds up in the brains of people with Alzheimer's.