Bacteriophages: Hidden Players in Parkinson's Disease?

— Viruses affect microbiome composition, perhaps fostering rogue neural proteins

MedicalToday

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ATLANTA -- Patients with Parkinson's disease saw significant shifts in the content of certain in the fecal microbiome, a researcher said here.

Notably, those patients with Parkinson's disease experienced a decrease in Lactococcus spp. abundance compared to controls, reported George Tetz, MD, of the Human Microbiology Institute in New York City.

These results were presented at a at the ASM Microbe meeting.

Tetz and his team have been studying the role of bacteriophages -- viruses that infect bacteria -- in a variety of diseases for several years. In 2016, he published an article in , first detailing how bacteriophage infections caused "increased intestinal permeability" in rats. Further research on rats was published the next year in , where Tetz cited research that "concomitant gut dysfunction" could play a role in Crohn's disease, IBD, chronic fatigue syndrome, diabetes, autism, cancer, neurodegenerative and cardiovascular diseases.

In an interview given to the in 2017, Tetz focused primarily on neurological conditions, citing another way that bacteriophages may be linked to the development of these diseases is through "the formation of prion proteins that have been shown to be associated with the formation of misfolded amyloid and tau-proteins in Alzheimer's disease."

Other recent research published in JAMA Neurology suggested a link between inflammation -- specifically in inflammatory bowel disease -- and Parkinson's disease.

Tetz's team used shotgun metagenomics sequencing to examine the fecal microbiome of 32 patients with Parkinson's disease and 28 controls. They observed that Lactococcus abundance in Parkinson's patients was about 10% that in controls, but the number of Lactococcal phages was approximately the same, the authors wrote.

"Bacteriophages have previously been overlooked as pathogenic factors, and the study points out their pivotal role in pathogenesis," Tetz said in a statement. "The depletion of Lactococcus due to high numbers of strictly lytic phages in PD patients might be associated with PD development and directly linked to dopamine decrease as well as the development of gastrointestinal symptoms of PD."

The authors observed that "abundances of lytic and temperate Lactococcus phages" were similar in controls, and said that these findings indicated "depletion of Lactococcus spp. in patients with PD can be explained by the appearance of these lytic phages."

Tetz's team said that this is the first study to suggest a link between bacteriophages and Parkinson's disease, and added that future research may be needed to explore these bacteriophages as both "a diagnostic and treatment target for therapeutic intervention," they concluded.

Disclosures

The authors disclosed no conflicts of interest.

Primary Source

ASM Microbe

Tetz G, Tetz V "Bacteriophages: are they an overlooked driver of Parkinson's disease?" ASM Microbe 2018; Abstract 117 - SUNDAY.