[Brain-gut interactions].

Our digestive tract has an autonomous functioning but also has a bidirectional relation with our brain known as brain-gut interactions. This communication is mediated by the autonomous nervous system, i.e., the sympathetic and parasympathetic nervous systems, with a mixed afferent and efferent component, and the circumventricular organs located outside the blood-brain barrier. The vagus nerve, known as the principal component of the parasympathetic nervous system, is a mixed nerve composed of 90% afferent fibers, which has physiological roles due to its putative vegetative functions. The vagus nerve has also anti-inflammatory properties both through the hypothalamic pituitary adrenal axis (through its afferents) and the cholinergic anti-inflammatory pathway (through its efferents). The sympathetic nervous system has a classical antagonist effect on the parasympathetic nervous system at the origin of an equilibrated sympathovagal balance in normal conditions. The brain is able to integrate inputs coming from the digestive tract inside a central autonomic network organized around the hypothalamus, limbic system and cerebral cortex (insula, prefrontal, cingulate) and in return to modify the autonomic nervous system and the hypothalamic pituitary adrenal axis in the frame of physiological loops. A dysfunction of these brain-gut interactions, favoured by stress, is most likely involved in the pathophysiology of digestive diseases such as irritable bowel syndrome or even inflammatory bowel diseases. A better knowledge of these brain-gut interactions has therapeutic implications in the domain of pharmacology, neurophysiology, behavioural and cognitive management.

Bonaz B 《-》

Inflammatory bowel diseases: a dysfunction of brain-gut interactions?

Bonaz B 《-》

The Vagus Nerve in the Neuro-Immune Axis: Implications in the Pathology of the Gastrointestinal Tract.

Bonaz B ，Sinniger V ，Pellissier S 《Frontiers in Immunology》

The Vagus Nerve at the Interface of the Microbiota-Gut-Brain Axis.

Bonaz B ，Bazin T ，Pellissier S 《Frontiers in Neuroscience》

Brain-gut interactions in inflammatory bowel disease.

Psycho-neuro-endocrine-immune modulation through the brain-gut axis likely has a key role in the pathogenesis of inflammatory bowel disease (IBD). The brain-gut axis involves interactions among the neural components, including (1) the autonomic nervous system, (2) the central nervous system, (3) the stress system (hypothalamic-pituitary-adrenal axis), (4) the (gastrointestinal) corticotropin-releasing factor system, and (5) the intestinal response (including the intestinal barrier, the luminal microbiota, and the intestinal immune response). Animal models suggest that the cholinergic anti-inflammatory pathway through an anti-tumor necrosis factor effect of the efferent vagus nerve could be a therapeutic target in IBD through a pharmacologic, nutritional, or neurostimulation approach. In addition, the psychophysiological vulnerability of patients with IBD, secondary to the potential presence of any mood disorders, distress, increased perceived stress, or maladaptive coping strategies, underscores the psychological needs of patients with IBD. Clinicians need to address these issues with patients because there is emerging evidence that stress or other negative psychological attributes may have an effect on the disease course. Future research may include exploration of markers of brain-gut interactions, including serum/salivary cortisol (as a marker of the hypothalamic-pituitary-adrenal axis), heart rate variability (as a marker of the sympathovagal balance), or brain imaging studies. The widespread use and potential impact of complementary and alternative medicine and the positive response to placebo (in clinical trials) is further evidence that exploring other psycho-interventions may be important therapeutic adjuncts to the conventional therapeutic approach in IBD.

Bonaz BL ，Bernstein CN 《-》