The discovery adds to growing evidence that suggests Parkinson's may start in the gut.
The findings come from an American research team at the annual meeting of the Society of Neuroscience ahead of publication.
Parkinson's protein travels from gut to brain
Lewy bodies are sticky protein clumps that form in brain cells affected by Parkinson's.
They are mainly made up of abnormal alpha-synuclein, a protein thought to be important for the spread of Parkinson's.
Researchers from the University of Alabama used mice to study the movement of the alpha-synuclein protein and investigate if the protein could move from the gut to the brain.
They injected a synthetic form of alpha-synuclein into the gut of mice and then used a state of the art technique to track its movement. After 60 days, they found the protein had travelled to the part of the brain affected in Parkinson's.
The link between Parkinson's and the gut
Sophie Mclachlan, Parkinson's UK Research Communications Officer, said:
Understanding how this protein gets to the brain could be key to finding ways to stop the progression of Parkinson's
"We know that many people with Parkinson's experience problems in their digestion – such as constipation – often before movement symptoms appear.
"This research supports previous studies that suggest the first changes in Parkinson's may happen in the gut before spreading to the brain.
"We have much to learn about the origins of Parkinson's. If it does really start in the gut, understanding how this protein gets to the brain could be key to finding ways to stop its progression."
Did you know...
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