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Study into nose-picking link to dementia

Scientists are trying to work out if a bacteria linked to dementia gets into human brains through the nose, like it does in mice.

October 28, 2022
By Marty Silk
28 October 2022

The potential link between picking your nose or plucking nose hairs and dementia will be part of a new study.

Griffith University researchers have proven that the Chlamydia pneumoniae bacteria that’s linked to late-onset dementia can enter the central nervous systems of mice through the olfactory nerves of their noses.

Professor James St John says mouse brain cells respond to the bacteria by depositing amyloid beta protein, which clumps into plaques disrupting neurons and cells in Alzheimer’s patients.

“We’re the first to show that Chlamydia pneumoniae can go directly up the nose and into the brain where it can set off pathologies that look like Alzheimer’s disease,” he said in a statement on Friday. 

“We saw this happen in a mouse model, and the evidence is potentially scary for humans as well.”

The study, published in the journal Scientific Reports, shows that viruses and bacteria can bypass the blood barrier by taking a shortcut directly to the brain via the olfactory nerve.

Prof St John says the team is plans another study to prove the same nasal pathway exists in humans, who also have the Chlamydia pneumoniae bacteria in their brains.

“What we do know is that these same bacteria are present in humans, but we haven’t worked out how they get there,” he said.

Loss of smell is an early indicator of Alzheimer’s disease, he said, so smell tests could potentially help provide an earlier diagnosis.

Prof St John also warned there was a potential risk that picking your nose or plucking nasal hairs could increase you chances of developing dementia.

“We don’t want to damage the inside of our nose and picking and plucking can do that. If you damage the lining of the nose, you can increase how many bacteria can go up into your brain.”

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