Role of the microbiome in the development of Parkinson's disease (Review)

Parkinson's disease (PD) is a disorder of the brain marked by the gradual loss of dopaminergic neurons in the substantia nigra, resulting in both motor and non‑motor symptoms. Emerging evidence indicates that the gut microbiota plays a crucial role in the development and progression of Parkinson's disease. The present review discusses the function of the gut microbiome in PD, including its makeup, interactions with the host and putative processes that relate microbial dysbiosis to neurodegeneration. In addition, the present review discusses the possibilities of diagnostic biomarkers and microbiome‑targeted therapeutics for PD. The present review synthesizes scientific literature data using a case‑control approach to provide a summary of the composition of the gut microbiota in patients with PD and healthy controls. The present review includes microbiological, clinical and biomarker data in an aim to provide a better understanding of the gut‑brain axis and its implications. Patients with PD have a lower microbial diversity and changes in certain bacterial communities, such as lower amounts of <em>Prevotellaceae</em> and greater amounts of <em>Enterobacteriaceae</em>. Dysbiosis can cause &alpha;‑synuclein misfolding, neuroinflammation and increased intestinal permeability, potentially leading to the development of PD through the gut‑brain axis. Probiotics, dietary changes and fecal microbiota transplantation all show promise for restoring microbial balance and relieving PD symptoms. Advances in metagenomics and artificial intelligence‑driven analysis help to clarify microbiome‑based therapies. The gut microbiota affects the gut‑brain axis, neuroinflammation and &alpha;‑synuclein aggregation, all of which contribute to the development of PD. Targeted microbiome therapeutics have the potential to improve illness management; however, more standardized, long‑term trials are required to determine causation and therapeutic effectiveness. The present review emphasizes the relevance of personalized techniques and modern technology in microbiome research for PD.