Parkinson's disease (PD) is described as a common, progressive neurodegenerative disorder with multiple pathogenic mechanisms. Recent research has focused on the microbiota‑gut‑brain axis as an important contributor to PD pathogenesis. The gut microbiota is presented in the review as a central transmitter within this axis that can modulate disease progression via several biological pathways. The review synthesizes current findings and highlights the gut as both a site of early disease manifestations and a potential therapeutic target.
The review emphasizes that non-motor symptoms — particularly gastrointestinal complaints — are often early features of PD and may reflect dysfunction along the microbiota‑gut‑brain axis. These non-motor presentations are considered both early manifestations and contributors to disease exacerbation. The authors note that despite the clinical importance of these signs, reliable diagnostic criteria or gut‑related biomarkers specific for PD have not been fully developed, indicating an unmet need for tools that can detect or predict PD through gut‑brain signals.
According to the review, the gut microbiota can affect PD through a variety of mechanisms. Key pathways identified include:
Neural routes: communication along the vagus nerve is presented as one route by which peripheral gut changes may influence central nervous system pathology.
Proteinopathy links: α‑synuclein is highlighted as a molecular factor relevant to PD that may be involved in gut‑to‑brain propagation or local gut pathology related to the microbiome.
Immune and inflammatory pathways: alterations in the gut microbiome may modulate systemic and local immune responses that in turn influence neuroinflammation associated with PD.
Metabolic and microbial products: microbial metabolites and other microbiota‑derived molecules are indicated as potential mediators of effects on host tissues relevant to PD.
The review frames these mechanisms as interrelated processes by which the intestinal microbiota contributes to PD pathophysiology, while acknowledging that details about the exact causal links and the relative importance of each pathway require further study.
The authors point out that, to date, there are no fully developed, reliable diagnostic criteria or biomarkers derived from gut microbiota research that can be used broadly in PD diagnosis or staging. Although non-motor gastrointestinal symptoms and microbiome alterations are associated with PD, the review states that validation of specific microbial signatures, metabolites, or other gut‑based biomarkers suitable for clinical use remains incomplete. The review therefore highlights an important translational gap between mechanistic findings and practical diagnostic tools.
The review outlines multiple strategies that have been developed or proposed to prevent or control PD by modulating the intestinal microbiome. These include:
Antibiotics: used experimentally or investigationally to alter gut microbial composition, though the review does not detail standardized regimens or long‑term consequences.
Probiotics: supplementation with live microorganisms intended to beneficially modify the gut ecosystem.
Prebiotics: dietary substrates designed to promote the growth of beneficial microbes.
Dietary interventions: broader nutritional modifications aimed at shaping the microbiome and host metabolism.
Fecal microbiota transplantation (FMT): transfer of donor fecal material to reconstitute or alter a recipient's gut microbiome.
Vagus nerve stimulation: an approach that targets the neural limb of the gut‑brain axis to modulate signaling between gut and brain.
The review presents these approaches as potential therapeutic options and notes that they are being investigated as ways to influence PD progression by acting on the gut microbiota or gut‑brain communication.
While multiple interventions have been proposed, the review highlights that these strategies face specific issues and challenges. For many approaches, the review indicates that there remain unresolved questions regarding efficacy, optimal protocols, safety, standardization, durability of effect, and translation from experimental models to humans. The abstract does not provide detailed outcome data or specific trial results, and thus the review underscores the need for further rigorous clinical and mechanistic research to address these gaps before microbiota‑targeted therapies can be widely recommended.
The review concludes that the microbiota‑gut‑brain axis offers valuable new angles for understanding PD and represents a promising area for therapeutic development. The gut microbiota is framed as a potential target to prevent or slow PD progression, but the authors stress that additional research is required to translate mechanistic findings into reliable diagnostics and safe, effective treatments. The review therefore serves as a synthesis of recent advances while calling attention to the limitations and the research needed to move from concept to clinical application.
(Note: The source abstract summarizes the review's scope and main themes. Specific experimental results, quantitative data, or detailed clinical trial outcomes were not reported in the abstract and therefore are not presented here.)