Australian researchers have discovered identical signs of brain damage in sleep apnoea patients as in people suffering with Alzheimer’s.
The RMIT research provides yet further confirmation of the link between the two diseases and may help to develop therapies for the treatment and potentially the prevention of Alzheimer’s.
The research found that the toxic amyloid plaques, which are a known indicator of Alzheimer’s disease, start in the same place and spread in the same way in the brains of people with obstructive sleep apnoea as they do with people with Alzheimer’s.
Obstructive sleep apnoea is a serious condition that occurs when a person’s breathing is repeatedly interrupted during sleep and it is increasingly common, with around 30 per cent of elderly people reporting the condition.
Around one in four Australian men aged over 30 have some degree of sleep apnoea.
Lead investigator Professor Stephen Robinson said scientists know the two diseases are related, but what drives the connection is still unclear.
“We know that if you have sleep apnoea in midlife, you’re more likely to develop Alzheimer’s when you’re older, and if you have Alzheimer’s you are more likely to have sleep apnoea than other people your age,” he said.
“The connection is there but untangling the causes and biological mechanisms remains a huge challenge.
“Our study is the first to find Alzheimer’s-like amyloid plaques in the brains of people with clinically verified obstructive sleep apnoea.
“It’s an important advance in our understanding of the links between these conditions and opens up new directions for researchers striving to develop therapies for treating, and hopefully preventing, Alzheimer’s disease.”
Patients who had sought treatment for their sleep apnoea still suffered from having amyloid plaque build-up in their brains.
The most common treatment for mild to severe sleep apnoea is continuous positive airway pressure, but the study found that this treatment made no difference to the amount of plaques found in the brain.
The study also found that there was a correlation between the severity of the sleep apnoea and the amount of build-up of amyloid plaques.
The study investigated the extent of Alzheimer’s-like indicators in autopsy tissue from the hippocampus (the area of the brain associated with memory) of 34 people and the brain stems of 24 people with obstructive sleep apnoea.
The subjects of the research showed no clinical symptoms of dementia before they died, suggesting they may have been in an early pre-dementia stage.
“While some people may have had mild cognitive impairment or undiagnosed dementia, none had symptoms that were strong enough for an official diagnosis, even though some had a density of plaques and tangles that were sufficiently high to qualify as Alzheimer’s disease,” Prof. Robinson said.
“The next stage for our research will be to continue analysing these samples to get a full understanding of the neuropathology, including signs of inflammation and changes to the blood vessels that supply nutrients to the brain.
“The sample size for this study was limited, so we would also like to work towards establishing a clinical study with a larger cohort.”
In April, a French study discovered that sleep-disordered breathing led to an increase in the amyloid burden of patients, meaning that people with sleep disorders had an increased risk of developing Alzheimer’s.
Do you suffer from obstructive sleep apnoea? Are you worried about developing Alzheimer’s disease later in life?
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