A condition such as Parkinson’s disease (PD) is one of the most complex neurological disorders. The causes and progression of this disease are determined to a lesser extent by genetic, and to a greater extent by biochemical factors. The significance of the first factor in the pathogenesis of this disease is already well understood. However, the contribution of other factors – such as nutrition, the environment, and the entire human lifestyle-continues to be largely unexplained. So far, more than 55% of patients with Parkinson’s disease suffer from regular constipation. As it was established, this factor can become one of the first symptoms of the disease. Statistics show that this symptom can appear 15-20 years before specialists diagnose PD. Also, recent studies have clearly shown a change in the microbiome of the large intestine in almost all patients with this condition, compared with the control group, of the same age. Despite these findings, the functional implications of these changes require further research.
To try to answer this question, a group of scientists from the Haukka Institute, together with colleagues from different countries, began to study changes in the composition of the intestinal microbial that are directly related to PD. Potentially influencing factors were also taken into account to better understand the functional metabolic consequences of changing the gut microbiome.
For example, the team of researchers tried to characterize the microbial composition of the stool and their abundance in various samples. All samples were taken from more than 140 patients with symptoms of Parkinson’s disease, from more than 150 completely healthy people from the control group.
All the data obtained on the composition of the microbiome in various patients with PD and healthy people from the control group were used to create personalized software models that simulate the metabolism of bacteria in the intestine. The simulation data allowed the researchers to more accurately predict the secretion in more than 120 bacterial metabolites. After that, all the data obtained were processed by statistical analysis to accurately determine the microbial and metabolic differences between patients with Parkinson’s disease and a group of healthy people.
The researchers found that exactly seven types of microbes and eight bacterial colonies significantly changed their relative content, compared to people with PD and the control group. Namely, the bacteria Akkermansia muciniphila as a result turned out to be the most modified species at the species level, since they became more common in patients with PD (compared to the control group).
Lactobacillus increased significantly in the number of patients with PD. Together with this, the Turicibacter group decreased very markedly compared to healthy people from the control group. The researchers noticed that changes in the composition of the microbiome in Parkinson’s patients also directly depend on gender, age, and the number of bowel disorders. This observation clearly shows the systemic nature of the development of Parkinson’s disease.