Is a stool transplant a potential treatment for Parkinson’s?

A recent study into Parkinson’s disease has shown that a stool transplant may constitute a new and valuable treatment of the disease. “It offers a potentially safe, effective and cost-efficient way of alleviating the symptoms and improving the quality of life of millions. A 'bacterial pill' might replace the stool transplant in the future. But more research is needed.”

An increasing number of people are suffering from Parkinson’s, a neurodegenerative condition that causes nerve cells in the brain to progressively deteriorate. Although we primarily know it as an age-related disease - the odds of developing the disease do increase with age - it often afflicts under-50s as well.

So much about the disease remains to be discovered. For instance, there is no definitive answer as to the cause of the disease. Scientists are increasingly looking towards combinations of genetic risk factors and environmental factors, such as nutrition. A discovery that points in this direction is the fact that the intestinal microbiome in Parkinson’s patients differs from that of non-patients.  Replacing that microbiome with a healthy microbiome through a stool transplant yields promising results.

This is exactly what professors Roosmarijn Vandenbroucke and Patrick Santens put to the test in a clinical study. Following additional research, the results may even lead to the development of a ‘bacteria pill’ or some other form of therapy that is easier and less invasive than a stool transplant.

What did you study exactly?

Professor Roosmarijn Vandenbroucke: We conducted a clinical study in which patients were given a stool transplant. A portion of the Parkinson’s patients received stool from healthy donors while another portion received placebos. After a year we examined the evolution of the typical symptoms of Parkinson’s in both target groups. We found that those patients who underwent a stool transplant with stool from a healthy donor exhibited a significant improvement compared to the placebo group.”

Do you know whether the effect is long-lasting?

Professor Patrick Santens: "The improvement of motor symptoms showed an upward trend. In other words, the results were even better than when we performed the same tests six months after the transplant. This may indicate a long-lasting effect but more research is needed to determine whether the treatment also slows down the evolution of the disease.”

So Parkinson’s is not merely the result of an ageing brain?

Professor Santens: We suspect that a number of environmental factors such as nutrition play a key role. This proves that in order to understand the disease we must go beyond pure brain research. This is the result of progressive understanding in this field. Up until fifteen years ago we were looking almost exclusively at the brain but meanwhile we have widened our scope considerably.”

To include nutrients, and therefore also the intestines?

Professor Santens: “A volume of research exists to prove the link between the gut and the brain and this is also the case with Parkinson’s disease. The microbiome in Parkinson’s patients is different than in healthy individuals.”

Professor Vandenbroucke: “It’s just that we don’t know what determines the nature of a microbiome or how it changes. In patients with Parkinson’s the intestines work slower and that in itself may already affect the microbial composition."

Why is it that so many unknowns remain when it comes to Parkinson’s?

Professor Santens: “All too often Parkinson’s is perceived as an age-related disease, subconsciously causing the general public to downplay its severity. However, this is not always the case. Although the onset of symptoms usually occurs around the age of sixty, Parkinson’s is also being diagnosed in a growing group of younger individuals. For example, I recently saw a patient who is now 45 years old and who has had the disease for a decade. These are people who lead an active life, also on a professional level. You can’t overestimate the impact of the disease on them and their environment. It is therefore wrong to classify Parkinson’s as an age-related disease.”

Given the growing number of cases, is more attention being paid to the disease?

Professor Santens: “It’s still rather limited and that is reflected in the limited resources at our disposal. Often the big bucks are allocated to other domains which, obviously, also need funding but the share of resources allocated to Parkinson’s is dishearteningly low. Nevertheless, the disease has a huge impact on society.”

Roosmarijn Vandenbroucke, professor in the Department of Biomedical Molecular Biology at the Faculty of Sciences, and group leader at the VIB Center for Inflammation Research.

Patrick Santens, professor at the Faculty of Medicine and Health Sciences and neurologist at Ghent University Hospital (UZ Gent), specialising in movement disorders.