Gut bacteria transplant may improve Parkinson’s movement symptoms

The human gut contains billions of microorganisms, including bacteria, which are collectively known as the gut microbiome. The bacteria in our gut are very important for healthy digestion, helping us break down food, make vitamins and fight infection.

These bacteria vary over time, depending on our diet and environment. Some evidence suggests that gut bacteria can vary in different health conditions. Previous research has shown that the gut bacteria in people with Parkinson’s is different to that of people without the condition. This could mean that changes in the gut microbiome may play a role in the development, or even the progression of Parkinson’s. Read about a recent study exploring the gut microbiome and Parkinson’s.

What did the researchers do?

The research team, based in Belgium, looked at whether replacing the gut bacteria in people with Parkinson’s with gut bacteria from healthy donors could improve symptoms of the condition.

46 people with Parkinson’s with mild to moderate symptoms were included in the study. Everyone received a faecal microbiota transplant (FMT), a procedure where bacteria and other microorganisms from a donor are transferred to the recipient’s gut through a tube which passes through the nose to the small intestine. Participants either received a sample from a healthy donor’s stool, or a sample from their own stool as a placebo.

All participants were monitored for a year after the treatment. The researchers looked at motor symptoms and non-motor symptoms of Parkinson’s in both groups, including constipation, a symptom commonly experienced by people with Parkinson’s. 

What were the results?

Results from the study showed that after 12 months, people with Parkinson’s who had received a FMT from a healthy donor saw significant improvements in their movement symptoms, compared to the placebo group. Those who received gut bacteria from healthy donors also tended to have less severe constipation.

There was no clear difference in any other non-motor symptoms between the groups, except that those who received gut bacteria from healthy donors reported that they were more tired at the end of the study.

These findings may suggest that FMTs may have long-lasting benefits on motor symptoms of Parkinson’s in people with mild to moderate symptoms. More research is required to confirm these benefits, and to look in more detail at the changes in gut bacteria of people with Parkinson’s before and after receiving a FMT from a healthy donor.

Read the full results in eClinicalMedicine.

Emma Rodgers, Research Communications Officer at Parkinson’s UK, comments:

"Exploring the possible link between Parkinson’s and the gut is a very active area of research. This study shows that FMTs are well tolerated and deemed safe for people with Parkinson’s. This may encourage further studies to take place.

"Whilst encouraging, it’s important to note that before the 12 month mark, no significant differences in motor symptoms were seen between the group receiving a FMT from healthy donors and the placebo group. This means that the placebo group also saw a large and long-lasting improvement in their symptoms up to 6 months after receiving a FMT from their own stool, suggesting that there was a strong placebo effect.

"We hope to see future studies to better understand the potential benefits of FMTs for Parkinson’s, as well as increase our knowledge of how the gut microbiome may be linked to the condition."