Mediators of stress effects in inflammatory bowel disease: not the usual suspects

Abstract

Empirical efforts to prove or disprove an association between stress and the course of inflammatory bowel disease (IBD) have had inconsistent results. Direct study of mediators of stress-related physiological processes may clarify this important area. Methods: candidate mediators were selected based on evidence that they have a role in the pathophysiology of IBD. Medline searches for original articles addressing each putative mediator and psychological stress were conducted. Articles were reviewed with goals of synthesis and hypothesis generation. Results: there is evidence that substance P (SP), vasoactive intestinal protein (VIP), tumour necrosis factor α (TNFα), oxidant molecules, endogenous glucocorticoids and heat shock proteins (HSPs) are involved in the stress response. Discussion: two principles emerge which should inform efforts to investigate stress in IBD. First, stress effects are regulated by highly interdependent systems. Second, the effects of mediators are highly specific to the location of their activity, and so, investigations in IBD are likely to require direct investigation of inflamed and unaffected gut tissue.