Detection, quantification, and isolation of Desulfovibrio species in the feces of Parkinson's disease patients and healthy controls

Parkinson’s disease (PD) is a chronic and progressive neurological disorder that affects a large number of elderly people(Hoehn & Yahr, n.d.). The hallmark feature of the disease is the death of nerve cells in the brain that produce dopamine due to the aggregation of a neuronal protein, alpha-synuclein, into toxic structures in nerve cells(Gorecki et al., 2019).As a result, people with PD experience tremors, stiffness, and difficulty in movement, which can have a significant impact on their quality of life. Despite extensive research efforts, the underlying cause of PD remains unknown. However, it is widely believed that a combination of genetic and environmental factors plays a role in its development. One area that has recently gained attention in the field of PD research is the gut-brain axis, a bidirectional communication pathway that connects the gut microbiota with the central nervous system(Hertel et al., 2019). It is now known that the gut microbiota, the community of microorganisms that resides in the gastrointestinal tract, plays a crucial role in maintaining the health of the host(Boertien et al., 2019). Alterations in the gut microbiota have been linked to a range of diseases, including metabolic disorders, inflammatory bowel disease, and neuropsychiatric disorders such as depression and anxiety(Barrenschee et al., 2017). In recent years, researchers have also been investigating the potential role of the gut microbiota in the pathogenesis of PD(Kleine Bardenhorst et al., 2023). One bacterial genus that has been implicated in the pathogenesis of PD is Desulfovibrio. Desulfovibrio bacteria are Gram-negative, sulfate-reducing bacteria that are commonly found in the human gut. Previous studies have shown that Desulfovibrio bacteria produce hydrogen sulfide(Haouzi et al., 2020), which can be toxic to nerve cells, and lipopolysaccharides, which can trigger an immune response and cause inflammation(Gorecki et al., 2019). In addition, some strains of Desulfovibrio bacteria have been shown to produce magnetite, a mineral that can induce the aggregation of α-synuclein(Murros et al., 2019). To investigate the role of this bacteria in pathogenesis of the disease I have conducted conventional and quantitative real-time PCR analysis of fecal samples from 10 PD patients and 10 healthy controls and found that all PD patients had Desulfovibrio bacteria in their gut microbiota, and these bacteria were present at higher levels than in healthy controls. Additionally, the concentration of Desulfovibrio species correlated with the severity of PD. Desulfovibrio bacteria produce hydrogen sulfide, lipopolysaccharide, and magnetite, all of which are likely to contribute to the oligomerization and aggregation of α-synuclein. These findings suggest that Desulfovibrio bacteria may be involved in PD pathogenesis. The substances produced by these bacteria may contribute to the development of the disease, and their presence in fecal samples may serve as a biomarker for PD. This study provides a potential avenue for the development of new treatments and identification of individuals at risk of developing PD.