Fecal Transplant: A New Approach for Parkinson’s Disease?

Distinct Gut Microbiome 

In an accompanying editorial, Timothy R. Sampson, PhD, assistant professor, Department of Cell Biology, Emory University School of Medicine, Atlanta, pointed out that dozens of independent studies have now demonstrated a distinct gut microbiome composition associated with Parkinson’s disease, and experimental data suggest that this has the capacity to incite inflammatory responses; degrade intestinal mucosa; and dysregulate a number of neuroactive and amyloidogenic molecules, which could contribute to the disease. 

He noted that three other small placebo-controlled studies of fecal transplantation in Parkinson’s disease showed slightly more robust responses in the active treatment group, including improvements in UPDRS scores and gastrointestinal symptoms.

However, these studies tested different FMT procedures, including lyophilized oral capsules given at different dosing frequencies and either nasojejunal or colonic transfusion following a standard bowel preparation.

In addition, there is no consensus on pretransplant procedures, such as antibiotics or bowel clearance, and the choice of donor microbiome is probably essential, because there may be certain microbes required to shift the entire community, Dr. Sampson wrote. 

Understanding how microbial contributions directly relate to Parkinson’s disease would identify individuals more likely to respond to peripheral interventions, and further exploration is needed to shed light on particular microbes that warrant targeting for either enrichment or depletion, he added. 

“Despite a lack of primary end point efficacy in this latest study, in-depth comparison across these studies may reveal opportunities to refine fecal microbiota transplantation approaches. Together, these studies will continue to refine the hypothesis of a microbial contribution to Parkinson’s disease and reveal new therapeutic avenues,” Dr. Sampson concluded.
 

‘Planting Grass in a Yard Full of Weeds’

Commenting on the research, James Beck, PhD, chief scientific officer of the Parkinson’s Foundation, New York, said that whether FMT are helpful remains to be determined. 

“The key question that needs to be solved is how to best perform these transplants. One issue is that you cannot plant grass when the yard is full of weeds. However, if you take too hard an approach killing the weeds — that is, with powerful antibiotics — you jeopardize the new grass, or in this case, the bacteria in the transplant. Solving that issue will be important as we consider whether this is effective or not.”

Dr. Beck added that there is still much to be learned from research into the gut microbiota. “I am hopeful with additional effort we will have answers soon.”
 

A version of this article appeared on Medscape.com.