Disturbed gut microbiome linked to Parkinson’s disease

Jan 16 2015

By Eleanor McDermid, Senior medwireNews Reporter

Research suggests that the intestinal microbiome may be altered in patients with Parkinson’s disease (PD), with some alterations being specific to the motor subtype.

The team found that bacteria from the Prevotellaceae family were significantly less abundant in the faeces of 72 PD patients than in 72 age- and gender-matched controls, at a median of 0.16% versus 0.77%, equating to a 77.6% reduction.

Low Prevotellaceae abundance (≤6.5%) was 86.1% sensitive for the presence of PD, but only 38.9% specific. Low levels were common in both groups, and Filip Scheperjans (Helsinki University Central Hospital, Finland) and co-workers note that reduced Prevotellaceae levels have also been reported in patients with autism and Type 1 diabetes.

High levels were rare in the PD group, however; even including outliers Prevotellaceae abundance remained below 30%, whereas it extended to about 80% in the control group.

“Based on these observations, high fecal abundance of Prevotellaceae could be a useful biomarker to exclude PD”, write Scheperjans et al in Movement Disorders.

They note that low abundance of bacteria from the Prevotella genus may reflect decreased mucin synthesis and therefore increased gut permeability.

“Investigating whether high abundance of Prevotellaceae has protective effects against PD or whether low abundance is rather an indicator of disturbed mucosal barrier function will be important”, says the team.

Adding Lactobacillaceae, Bradyrhizobiaceae and Clostridiales Incertae Sedis IV reduced sensitivity to 47.2% but increased specificity to 90.3%, and accounting for constipation (Wexner total score) improved sensitivity to 66.7% while maintaining specificity at 90.3%.

When looking at motor subtypes, the researchers found that Enterobacteriaceae were significantly more abundant in patients with the postural instability and gait difficulty subtype than in those with a tremor-dominant subtype, at respective medians of 0.46% and 0.04%. Other factors did not significantly differ between these two subgroups.

In total, the researchers analysed bacteria from 360 genera, 125 families, 60 orders, 29 classes and 18 phyla. However, they suggest that a broader analysis could improve accuracy. They conclude: “Because bowel dysfunction occurs in the premotor phase of PD and the microbiome of an individual is remarkably stable over time, investigating whether microbiota analysis could be used as a biomarker for premotor PD seems worthwhile.”

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