Gut microbiota-immune-brain axis (MGB axis)

The gut microbiota-immune-brain axis is a complex, bidirectional communication network that integrates the gastrointestinal tract, its resident microbial community, the immune system, and the central nervous system (Cryan et al., 2019). This axis operates through multiple pathways, including the vagus nerve, the hypothalamic-pituitary-adrenal (HPA) axis, and the production of microbial metabolites such as short-chain fatty acids (SCFAs) and neurotransmitters like GABA and serotonin (Mayer et al., 2015). The immune system acts as a critical intermediary, where gut-derived signals influence systemic inflammation and neuroinflammation, thereby affecting brain health and behavior (Dinan & Cryan, 2017). Dysregulation of this axis has been linked to various pathologies, including neurodegenerative diseases like Parkinson's and Alzheimer's, psychiatric conditions such as major depressive disorder, and functional gastrointestinal disorders like irritable bowel syndrome (Cryan et al., 2019). While not a single molecular target, the axis is a focal point for therapeutic interventions such as probiotics, prebiotics, and fecal microbiota transplantation (FMT) aimed at restoring homeostatic signaling (Mayer et al., 2015). These interventions seek to modulate the microbial environment to produce beneficial neuroactive compounds and reduce pro-inflammatory signaling to the brain.

Other names

Microbiota-gut-brain axisGut-brain axisGBACommensal microbiota-immune-brain signaling

Modulation of the bidirectional communication between the gut microbiota and the central nervous system through neural (vagus nerve), endocrine (HPA axis), and immune (cytokine) pathways, often involving microbial metabolites like short-chain fatty acids (Cryan et al., 2019).