A trial led by Helsinki University showed fecal microbiota transplants (FMTs) from healthy donors do not significantly improve symptoms of Parkinson’s disease in patients with the condition who had abnormal gut microbiome composition on enrollment.
The transplants were safe and well tolerated, according to Filip Scheperjans, a neurologist and researcher at the University of Helsinki who led the study, and colleagues. While no significant change in Movement Disorder Society Unified Parkinson’s Disease Rating Scale was seen at six months, patients given FMTs were taking less dopaminergic medication than those given placebo.
Earlier studies have shown that gut microbiome dysfunction is a common symptom in Parkinson’s disease patients.
“Gut microbiota impacts Parkinson’s disease pathology and symptoms, and gut microbiota composition is linked to motor and nonmotor symptoms as well as disease progression,” write Scheperjans and team in JAMA Neurology.
“Interventions targeting gut microbiota, such as FMT, have shown promising symptomatic and potentially neuroprotective effects in Parkinson’s disease animal models. The underlying mechanisms are incompletely understood but could involve changes in metabolism and immune activation,” they add.
This study included 45 people with Parkinson’s disease and an abnormal gut microbiome. The participants received one dose of FMT or placebo via colonoscopy in a 2:1 ratio. The FMT came from one of two healthy donors with an apparently normal gut microbiome composition.
The group was followed up for 12 months and the primary endpoint of the study was change of Movement Disorder Society Unified Parkinson’s Disease Rating Scale at six months follow up.
There was no significant differences in the Parkinson’s rating scale between the treatment and placebo group at 6 months. Gastrointestinal adverse events were seen in 53% of the FMT group versus 7% of the placebo group but were not serious.
Secondary outcomes were mixed, with dopaminergic medication use increasing significantly in the placebo group at six months.
“While those receiving FMT did not show clinical symptom improvements comparatively, this increase in levodopa equivalent daily dose may indicate that the placebo group progressed more quickly, requiring increased medication regimen,” suggests accompanying editorial author Timothy Sampson, a researcher at Emory University School of Medicine.
“Speculatively, this may also suggest that microbial metabolism of levodopa is beneficially impacted by FMT, as has been proposed.”
Anxiety symptoms were lower in the FMT group vs placebo, but other symptoms had improved more in the placebo group than FMT group at 12 months. Notably, there did appear to be some differences in results depending on the donor the FMT originated from.
“Further studies—for example, through modified FMT approaches or bowel cleansing—are warranted regarding the specific impact of donor microbiota composition and dysbiosis conversion on motor and nonmotor outcomes as well as medication needs in Parkinson’s disease,” conclude the authors.
