Reviews and PerspectivesReviews in Basic and Clinical Gastroenterology and HepatologyBrain-Gut Interactions in Inflammatory Bowel Disease
Section snippets
Neuroanatomical Basis of the Brain-Gut Axis
The brain and the gut communicate through the autonomic nervous system (ANS) and the circumventricular organs8 both in physiological and pathological conditions. The ANS, represented by the parasympathetic and sympathetic nervous systems (SNS), includes the vagus nerves (VNs), the sacral parasympathetic pelvic nerves, and the splanchnic nerves. These are mixed nerves containing afferent fibers (90% for VNs and 50% for sympathetic nerves) and efferent fibers facilitating neurotransmission
Stress and the CRFergic system
Stress is the response of the organism to a solicitation of the environment.10 The reaction of stress is physiologic but may become pathologic in the case of an imbalance between the capacities of adaptation and the requirement of the environment, leading to functional, metabolic, and even lesional disorders.11 The HPA axis is the classic pathway through which stress induces an adaptation. Corticotropin-releasing factor (CRF), the principal neuromediator of stress, directly administered into
Altered Psychological Functioning Before and After Diagnosis of IBD
Whether or not depression and anxiety actually have an effect on the inflammatory state in IBD and secondarily on disease expression, it is well known from community studies that a great deal of the functional impairment and disability associated with health conditions is related to the presence of anxiety or depression.82, 83, 84 Subjects with more depressive symptoms exhibit enhanced inflammation to a stressor compared with those with fewer depressive symptoms.85 Individuals with IBD have
Translational Implications With Therapeutic Applications Through the Brain-Gut Axis
Anti-TNF therapy is the gold standard in the treatment of patients with moderate to severe IBD.145 An alternative therapy to conventional anti-TNF treatment, based on brain-gut interactions, is stimulation of the cholinergic anti-inflammatory pathway, either pharmacologically or through VNS or nutrition (Figure 4).
Conclusion
Increasing knowledge gained from animal models exploring the brain-gut axis has provided potential insight into the management of IBD in humans. Depression and stress may both result from active IBD but may also play a role in triggering or magnifying symptoms in patients with IBD. The important symptoms of pain and fatigue, frequently reported by patients with IBD,163 are affected by a patient's mental health. Completely abrogating the inflammatory state may not eliminate these symptoms.164,
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Conflicts of interest The authors disclose no conflicts.
Funding Dr Bernstein is supported in part by the Bingham Chair in Gastroenterology. He has served as a consultant to Abbott Canada, Janssen Canada, Shire Canada, Vertex Pharmaceuticals, and Bristol-Myers Squibb and has received a research grant from Abbott Canada and an educational grant from Aptalis Pharmaceuticals. Dr Bonaz has served as a consultant to Abbott France, Almirall France, Cephalon France, Ferring France, MSD France, and Otsuka Pharmaceutical France.