The finding that the onset of Parkinson’s disease, one of the world’s most common debilitating brain disorders, has a functional link with the bacteria in the gut, is about to bring forth a radical change in the condition’s treatment.
The best target for treatment may be the gut, rather than the brain, according to a new study published in the journal Cell.
It was a team of scientists from several institutions in the US and Europe that showed how changing the bacteria in the guts of mice affected the manifestation of Parkinson’s symptoms.
The researchers, who even included bacteria taken from the guts of humans with the disease, hope the new information can be used to develop “next generation” probiotics.
Parkinson’s disease is a neurodegenerative disorder where brain cells accumulate excessive amounts of a protein called alpha-synuclein and then die off.
Patients lose motor function, experience tremors and shaking, and suffer other physical and mental effects.
One million people in the US and up to 10mn worldwide suffer from the condition, which is considered the world’s second most common neurodegenerative disease after Alzheimer’s.
It rarely runs in families; instead it appears to be influenced by environmental factors.
Previous research has suggested connections between gut bacteria and Parkinson’s, as well as other diseases such as multiple sclerosis.
But no research has shown exactly how the two might be related.
In this study, the researchers performed three different experiments that showed the link between the germs in the gut and the disease in the brain.
Researchers used mice genetically programmed to develop Parkinson’s as they produced very high levels of alpha-synuclein.
But only those animals with bacteria in their stomachs developed symptoms.
Sterile mice remained healthy.
Further tests showed transplanting bacteria from Parkinson’s patients to mice led to more symptoms than bacteria taken from healthy people.
Dr Timothy Sampson, one of the researchers at the California Institute of Technology, said: “This was the ‘eureka’ moment, the mice were genetically identical, the only difference was the presence or absence of gut microbiota. Now we were quite confident that gut bacteria regulate, and are even required for, the symptoms of Parkinson’s disease.”
In other words, it could mean that the guts of Parkinson’s patients have certain bacteria that contribute to the disease, or that they lack certain beneficial bacteria that could help protect against the disease.
Samples of gut bacteria in Parkinson’s patients render this possible.
They tend to have certain kinds of bacteria not found in healthy people, and they also lack others that are found in healthy people, noted Sarkis Mazmanian, one of the researchers on the team and professor of microbiology at the California Institute of Technology.
Moving forward, Mazmanian said the team would like to identify specific bacteria that are helpful of harmful and understand how they might contribute to or prevent the disease, and what kinds of treatments might produce the microbiome that best protects against the disease.
Given that Parkinson’s is currently incurable, the discovery that changes in the microbiome may be involved in the disease is a paradigm shift and opens entirely new possibilities for treating patients.
