The Gut-Brain Axis in Neurodegeneration: Mechanistic Links Between Dysbiosis and Neuropathology.
Level 5 - mechanism / opinion, no new human data
Narrative review synthesizing mechanistic pathways without original human data or systematic review methodology
PubMed 42602177 · doi:10.22034/ijp.2026.2081887.3613
What was done
This narrative review synthesizes proposed mechanistic pathways connecting gut dysbiosis to neurodegenerative pathology, specifically Alzheimer's disease, Parkinson's disease, and multiple sclerosis. It examines cascades involving intestinal permeability, blood-brain barrier disruption, neuroinflammation, neuroglial dysfunction, protein aggregation, and potential microbiome-targeted interventions.
What was found
No quantitative data or statistical results were reported in the abstract. The authors outline a conceptual cascade in which gut dysbiosis leads to leaky gut, allowing bacterial products (lipopolysaccharides, bacterial amyloids) and pro-inflammatory cytokines into the systemic circulation. These factors compromise the blood-brain barrier and induce neuroglial dysfunction, contributing to amyloid and tau pathology in Alzheimer's disease, synuclein aggregation in Parkinson's disease, and oligodendrocyte apoptosis with demyelination in multiple sclerosis.
Why it matters
It outlines how gut-derived inflammatory signals and microbial products might drive central nervous system proteinopathies, highlighting the microbiome as a potential therapeutic target.
Limits
The review provides narrative mechanistic reasoning without original empirical data, sample sizes, or systematic review methodology. The causal and temporal relationships between dysbiosis and neurodegeneration remain unproven hypotheses rather than clinically verified findings.
Cited by
- supports Changes in gut bacteria leading to intestinal permeability cause increased systemic inflammation that activates microglial cells.
- supports Lipopolysaccharide (LPS) leaking from the gut challenges immune cells to produce inflammatory cytokines that cross to the brain and stimulate microglial cells to become neurodestructive.