By JON ROGERS
Wed, Jan 11, 2017
SCIENTISTS have performed a complete about turn on the thinking on the causes of Parkinson’s disease, saying the condition may be caused by damage to the gut rather than the brain.
The discovery could open the way to new developments in combating the disease even before symptoms occur.
Prof David Burn of the University of Newcastle said: “That would be game-changing.
“There are lots of different mechanisms that could potentially stop the spread.
The discovery could open the way to new developments in combating the disease even before symptoms occur.
Prof David Burn of the University of Newcastle said: “That would be game-changing.
“There are lots of different mechanisms that could potentially stop the spread.”
The degenerative disease involves the death of neutrons in the brain which cause tremors, stiffness and problems with mobility.
Drugs are available to help combat the disease but they become less effective as the disease develops.
One of the hallmarks of the condition is deposits of insoluble fibres of a substance called synuclein.
These are usually found as small soluble molecules in healthy nerve cells, in people with Parkinson’s, something causes the synuclein molecules to warp into a different shape, making them clump together as fibres.
The indications that this transition may start outside the brain came about a decade ago, when pathologists reported seeing the distinctive synuclein fibres in nerves of the gut during autopsies – both in people with Parkinson’s and in those without symptoms but who had the fibres in their brain.
They suggested the trigger was some unknown microbe or toxin.
Conceptual computer artwork of Parkinson's Disease
This matched with people’s experience of suffering from the disease who reported digestive problems - mainly constipation.
Another early sign of the disease is the loss of smell which Prof Burn believes is no coincidence.
The nose and gut are two organs where nerve cells are exposed to the outside world - and to potentially damaging toxins and microbes.
Now, the synuclein fibres have been shown travelling from the gut to deep within the brain.
Coronal view of a human brain in Parkinsons disease. Blue/green areas highlight fibre of the motor
Collin Challis at the California Institute of Technology and his colleagues injected synuclein fibres into the stomach and intestine of mice.
Just three weeks later the fibres could be seen at the base of the brain, and by two months they had travelled to parts of the brain that control movement.
Mirroring the effects of Parkinson’s the mice also became less agile.
The findings were reported to the Society for Neuroscience in San Diego last month.
Prof Burn has indicated that people who have had the main nerve to their stomach cut, which was an old treatment for stomach ulcers, had a lower risk of developing Parkinson’s.
No single bacterium or virus has been pinpointed as the cause.
But early evidence suggests that people with Parkinson’s have different gut bacteria to healthy people. Some doctors are already experimenting with treating patients with antibiotics or faecal transplants.
“It could be that having the wrong bacteria in your gut triggers inflammation,” says Sébastien Paillusson at King’s College London. “We know that inflammation makes synuclein more likely to aggregate.”
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