A bug often found in the digestive tract of human beings could be a cause of Parkinson's disease, a new study has found. Researchers at the University of Helsinki and the University of Eastern Finland believe the bacteria desulfovibrio (DSV) could be at the root of the debilitating disease.
Often found in wet, boggy environments, DSV is thought to trigger a build-up of toxic proteins which then damages vital brain cells. By now demonstrating a potential path from the presence of the bacteria to physical changes in the brain that coincide with Parkinson's disease, the researchers hope to one day improve early diagnosis of the disease in humans, or even slow its progress.
"Our findings make it possible to screen for the carriers of these harmful Desulfovibrio bacteria," says senior author Per Saris, a microbiologist at the University of Helsinki in Finland.
"Consequently, they can be targeted by measures to remove these strains from the gut, potentially alleviating and slowing the symptoms of patients with Parkinson's disease."
The research was published in Frontiers in Cellular and Infection Microbiology. If true, it could be a major breakthrough in the study of the devastating illness, which affects 1450,000 Brits.
The main symptoms of Parkinson's disease include involuntary shaking of particular parts of the body, slow movement and stiff and inflexible muscles.
As part of their study, they took faecal samples from 10 Parkinson's patients and their healthy spouses. Lab tests showed that all of the Parkinson's patients had the bacteria in their faeces, along with eight of their partners.
DSV strains were then fed to organisms called nematode worms — which are known for making copies of protein alpha-synuclein. A build-up of this protein is believed to trigger the condition. The researchers also fed some worms the bacteria E-coli as a control.
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Results showed worms fed DSV strains from Parkinson's patients bore 'significantly' higher levels of the protein, compared to ones fed the same bacteria from healthy individuals or E-coli.
It is thought that, in time, the research may allow doctors to manage the progress of Parkinson's disease using therapies that target the digestive system and its surrounding nerves, instead of the brain.
"Once the Desulfovibrio bacteria are eliminated from the gut, α-synuclein aggregates are no longer formed in intestinal cells, from which they travel towards the brain via the vagus nerve like prion proteins," Saris said.
"Our findings are significant, as the cause of Parkinson's has gone unknown despite attempts to identify it throughout the last two centuries.
"The findings indicate that specific strains of DSV bacteria are likely to cause Parkinson's.
"The disease is primarily caused by environmental factors, that is, environmental exposure to the DSV bacterial strains that cause Parkinson's.
"Only a small share, or roughly 10 per cent, of Parkinson's is caused by individual genes."
