Beijing 2022

Alpha-synuclein accumulation in a nerve cell. (Image: Timo Myöhänen's research group.)


Parkinson's disease is a debilitating disorder that affects millions of people worldwide. While the disease has been studied for over 200 years, its cause remains unknown. However, researchers at the University of Helsinki have made a significant breakthrough by identifying certain strains of Desulfovibrio bacteria as the probable cause of Parkinson's disease in most cases.

The researchers' study has made it possible to screen for carriers of the Desulfovibrio bacteria and to remove the bacteria from the gut, thereby preventing the disease. The study's lead researcher, Professor Per Saris, explains that most cases of Parkinson's disease are caused by environmental factors, which means that people acquire the Desulfovibrio bacteria that cause the disease from their surroundings. Only a small percentage of cases, around 10%, are caused by genetic factors.

The study aimed to determine whether Desulfovibrio bacteria found in Parkinson's disease patients could cause the development of the disease. The researchers' main finding was that Desulfovibrio bacteria in Parkinson's disease patients caused the aggregation of the alpha-synuclein protein, a hallmark of Parkinson's disease, in model organisms, specifically in the Caenorhabditis elegans worm.

The study also found that Desulfovibrio bacteria isolated from healthy individuals did not cause alpha-synuclein aggregation to the same extent as the Desulfovibrio bacteria found in Parkinson's disease patients.

The study's results open the door for screening studies to identify people who carry harmful Desulfovibrio bacteria, so that measures can be taken to remove the bacteria from their gut. This could help alleviate and slow the symptoms of Parkinson's disease in patients.

"When Desulfovibrio bacteria are removed from the gut, they cannot cause any more alpha-synuclein aggregates in the gut's cells. These aggregates can then no longer progress to the brain through the enteric nervous system, like prion proteins, and this could alleviate Parkinson's disease symptoms," says Saris.

The study's findings are significant because they offer a potential avenue for the prevention and treatment of Parkinson's disease. However, further studies are needed to confirm the results and develop effective therapies. Nevertheless, the study is an important step forward in understanding the causes of Parkinson's disease and developing targeted therapies to treat and prevent the disease.