Gut microbiome connected to Parkinson’s and Alzheimer’s, research suggests

15 Nov 2017 --- New research released has revealed the links between the gut microbiome – the population of microorganisms living in the gastrointestinal tract – and brain diseases such as Parkinson's and Alzheimer's, including potential new ways to track and treat these diseases. The studies were presented at Neuroscience 2017, the annual meeting of the Society for Neuroscience.

The brain-gut axis has been discussed in the nutrition industry for some time, and companies such as Lallemand have released probiotics and similar products focused on the connection. Recent studies into the benefits of a healthy gut microbiome have included one stating that the “ridiculously healthy” elderly have the same gut microbiome as healthy 30-year-olds. 

Gut provides promising pathway to cures
Humans have roughly as many bacterial cells in their bodies as human cells, the Society for Neuroscience points out, and most of those bacteria live in the gut. Almost 100 trillion microbes – some beneficial and some harmful – live in the human gastrointestinal tract at any time, helping to regulate immune function and inflammation, two factors hypothesized to play a role in neurodegenerative diseases like Parkinson’s and Alzheimer’s. As brain-focused cures for such diseases remain elusive, scientists are looking to the microbiome for new insight and novel strategies.

The new findings presented by the Society for Neuroscience show that:

• Metabolites derived from the microbiome block protein misfolding in test tubes and prevent neurodegeneration in a fly model of a disease related to Parkinson's, hinting that gut-derived metabolites may hold therapeutic promise.
• A rat model of Parkinson's disease displays increased levels of an inflammatory protein in the colon, identifying a possible new biomarker for the disease.
• Nonhuman primates that received stomach injections of a protein associated with Parkinson's disease show signs of the disease in their brains, revealing that pathology can spread from the gut to the brain.
• A gene associated with risk for Alzheimer's disease influences the gut microbiome of mice, potentiating a novel treatment strategy.
• Probiotic treatment corrects memory problems in an Alzheimer's mouse model, suggesting that altering the microbiome may help delay the disease.

“The results presented today add to the growing body of evidence showing the influence of the gut on the brain and the crucial relationship between the two,” says moderator Tracy Bale, Ph.D., of the University of Maryland School of Medicine and Center for Brain Development and Maternal Mental Health, during a press conference. “Targeting the gut introduces a different and promising angle to tackle brain disorders across the lifespan.”