Findings may lead to new clinical laboratory testing and treatments for Parkinson’s patients
Gut bacteria have repeatedly been proven to perform critical roles in the development of certain diseases. And many clinical laboratory tests use human microbiota as biomarkers.
Now, researchers at Nagoya University Graduate School of Medicine in Japan have discovered a link between microbes in the gut and the brain. The connection may play a part in the development of Parkinson’s disease, according to a Nagoya University news release.
The researchers found that a reduction in the genes responsible for synthesizing riboflavin (vitamin B2) and biotin (vitamin B7) may increase the likelihood of developing Parkinson’s.
They also determined that the lack of these genes may lessen the integrity of the intestinal barrier that prevents toxins from entering the bloodstream causing the inflammation often seen in Parkinson’s patients.
The scientists published their findings in the Nature journal NPJ-Parkinson’s Disease titled, “Meta-analysis of Shotgun Sequencing of Gut Microbiota in Parkinson’s Disease.”
“Supplementation therapy targeting riboflavin and biotin holds promise as a potential therapeutic avenue for alleviating Parkinson’s symptoms and slowing disease progression,” said lead researcher Hiroshi Nishiwaki, PhD, Division of Neurogenetics, Center for Neurological Diseases and Cancer, Nagoya University Graduate School of Medicine, in a news release. (Photo copyright: Nagoya University.)
Key Deficiencies in Parkinson’s Patients
According to the Parkinson’s Foundation, nearly one million people in the US are living with Parkinson’s and that number is expected to increase to 1.2 million by the year 2030. Approximately 90,000 new cases of Parkinson’s are diagnosed in the US each year, and more than 10 million people are living with the disease worldwide.
To perform their research, the Nagoya University team analyzed stool samples from 94 Parkinson’s patients from Japan, the US, Germany, China, and Taiwan. They also included 73 relatively healthy controls from Japan. They then used shotgun sequencing (a laboratory technique for determining the DNA sequence of an organism’s genome) to gain a better understanding of the microbial community and genetic makeup of each sample.
The scientists discovered a decrease in B2 and B7 vitamins in patients diagnosed with Parkinson’s. B vitamins promote the production and functions of short-chain fatty acids (SCFA) and polyamines.
“Supplementation of riboflavin and/or biotin is likely to be beneficial in a subset of Parkinson’s disease patients, in which gut dysbiosis plays pivotal roles,” the authors wrote in NPJ-Parkinson’s Disease.
The examination of fecal metabolites in Parkinson’s patients revealed a reduction in both components.
“Deficiencies in polyamines and SCFAs could lead to thinning of the intestinal mucus layer, increasing intestinal permeability, both of which have been observed in Parkinson’s,” said Hiroshi Nishiwaki, PhD, a professor at Nagoya University Graduate School of Medicine and a lead researcher for the study, in the news release.
“This higher permeability exposes nerves to toxins, contributing to abnormal aggregation of alpha-synuclein, activating the immune cells in the brain, and leading to long-term inflammation,” he added.
The team surmises that the weakened protective layer in the gut exposes the intestinal nervous system to more of the toxins people experience in everyday life, such as chemicals, pesticides, and herbicides. These types of toxins lead to the overproduction of alpha-synuclein fibrils. These molecules are aggregates of the α-synuclein protein that form into long, thread-like structures which are primarily found in the brains of individuals with neurodegenerative diseases like Parkinson’s.
Alpha-synuclein fibrils amass in dopamine-producing cells in the brain and increase the type of inflammation that leads to the debilitating motor skills and dementia symptoms of Parkinson’s.
Precision Medicine Analysis Suggested
Due to their research, the team proposes that high doses of vitamin B may help reduce the damage of toxins on the gut microbiome, help protect against neurodegenerative diseases like Parkinson’s, and aid in the creation of personalized therapy plans for patients.
“We could perform gut microbiota analysis on patients or conduct fecal metabolite analysis,” Nishiwaki noted. “Using these findings, we could identify individuals with specific deficiencies and administer oral riboflavin and biotin supplements to those with decreased levels, potentially creating an effective treatment.”
The results of the Nagoya University study illustrate the importance of a healthy gut microbiome in the prevention of disease. Altering the bacterial level in the gut may enable doctors to stave off the progression of neurodegenerative illnesses like Parkinson’s disease.
—JP Schlingman
