The Role of Bacteria in Parkinson's Disease Development

Wednesday - May 10 2023, 06:05 UTC - 1 year ago

A new study from researchers from the University of Helsinki and the University of Eastern Finland has found that Desulfovibrio bacteria found in the human gut may play a key role in the development of Parkinson's disease. The findings indicate that specific strains of this bacteria are likely to cause Parkinson’s disease, with environmental exposure to the bacteria being a major factor. The resulting toxins can travel towards the brain via the vagus nerve, where they cause alpha-synuclein proteins to form toxic clumps, a key feature in the pathology of Parkinson’s disease.

Parkinson's disease is a progressive brain disorder often characterized by uncontrollable movements. Despite years of scientific research, the exact cause of this disease remains unknown. While even the role of genetic changes in Parkinson's disease is also not fully understood. Individual genes, according to experts, cause only a small percentage of Parkinson's disease (roughly 10 percent).

A new study has now sought a possible explanation for the disease's progression.

--- Bacteria, the main culprit? --- .

The study found that a microbe known as Desulfovibrio, which is found in the human gut, may play a key role in the development of Parkinson's disease. "The findings indicate that specific strains of Desulfovibrio bacteria are likely to cause Parkinson’s disease. The disease is primarily caused by environmental factors, that is, environmental exposure to the Desulfovibrio bacterial strains that cause Parkinson’s disease," said Professor Per Saris from the University of Helsinki in an official release.

Certain strains of this bacteria excrete compounds that cause neuronal proteins, alpha-synuclein, found inside brain cells to form toxic clumps. These proteins are generally studied to examine the pathology of this debilitating disease.

The researchers tried to investigate if the Desulfovibrio strains found in Parkinson's patients caused the formation of these protein clumps or not. The team conducted this study on the model organism: the worm Caenorhabditis elegans. These worms were fed with Desulfovibrio bacteria obtained from Parkinson's patients.

The findings show that the presence of these bacteria strains caused significant aggregation of the α-synuclein protein in a model organism for Parkinson's disease.

However, the results showed that Desulfovibrio strains isolated from healthy individuals did not cause the same level of protein accumulation. While the clumps formed by these bacteria strains in Parkinson's disease patients were also found to be larger.

"Our findings make it possible to screen for the carriers of these harmful Desulfovibrio bacteria. Consequently, they can be targeted by measures to remove these strains from the gut, potentially alleviating and slowing the symptoms of patients with Parkinson’s disease. Once the Desulfovibrio bacteria are eliminated from the gut, α-synuclein aggregates are no longer formed in intestinal cells, from which they travel towards the brain via the vagus nerve like prion proteins," concludes Saris.

The study is conducted by researchers from the University of Helsinki and the University of Eastern Finland. The study has been published in the journal Frontiers in Cellular and Infection Microbiology.