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Putting your fingers in your nose is a bad habit, according to researchers. This practice would facilitate the entry of germs into the brain, responsible for inflammation or even dementia such as Alzheimer’s disease.
Picking your nose is not trivial. This familiar gesture could promote the spread of bacteria and viruses, such as Chlamydia pneumoniae. At least that’s what emerges from a new study conducted by Griffith University and published in the journal Scientific Reports.
The bacteria can travel through the nose
It is by inoculating the bacteria Chlamydia pneumoniae in the nasal passages of mice, that the researchers discovered the mechanism behind the brain infection.
“By isolating live C. pneumoniae from tissues and using immunohistochemistry, we show that C. pneumoniae can infect the olfactory and trigeminal nerves, olfactory bulb, and brain within 72 h in mice.“, say the researchers.
Indeed, it is in the brain that the bacteria Chlamydia pneumoniae (a type of bacteria that can cause respiratory tract infections)”creates markers that are a telltale sign of Alzheimer’s disease“.
Interestingly, accumulations of beta-amyloid (a protein that aggregates into plaques in the brains of Alzheimer’s disease patients) were also detected in the olfactory system of mice. The problem ? Once in the brain, these plaques disrupt patients’ reasoning ability and memory.
This is why “theis made of sTouching your nose or pulling nose hairs is not a good idea.“, assures Professor St John, director of the Clem Jones Center for Neurobiology and Stem Cell Research and co-author of the study.
However, further work is needed to confirm these first results.
“We need to replicate this work in humans and confirm if the nasal passage works the same way. What we do know is that these same bacteria are present in humans.” he specifies.
Inflammation of the brain by a virus: a common process
According to Dr. Trivalle, this study is not the first to associate a viral infection with neuroinflammation.
“There are many theories about this. Any infection that remains a little too localized would trigger an inflammatory process in the brain. The traces of this infection would then cause a chronic immunological process. A not surprising mechanism when we know that the olfactory neurons present in the nose are connected to the brain. This is also the hypothesis put forward for the Covid“, reveals the head of the Alzheimer follow-up care and rehabilitation service in geriatrics at the Paul-Brousse hospital (AP-HP).