Published online Jun 7, 2020. doi: 10.3748/wjg.v26.i21.2702
Peer-review started: January 21, 2020
First decision: March 15, 2020
Revised: March 26, 2020
Accepted: May 13, 2020
Article in press: May 13, 2020
Published online: June 7, 2020
Inflammatory bowel disease (IBD) is an inflammatory disorder of the gastrointestinal tract that affects millions of patients worldwide. It has a complex and multifactorial etiology leading to excessive exposure of intestinal epithelium to microbial antigens, inappropriate activation of the immune system and ultimately to the damage of intestinal tissues. Although numerous efforts have been made to improve the disease management, IBD remains persistently recurring and beyond cure. This is due largely to the gaps in our understanding of the pathogenesis of IBD that hamper the development of timely diagnoses and effective treatment. However, some recent discoveries, including the beneficial effects of interleukin-22 (IL-22) on the inflamed intestine, have shed light on a self-protective mechanism in IBD. Regenerating islet-derived (REG/Reg) proteins are small secretory proteins which function as IL-22’s downstream effectors. Mounting studies have demonstrated that IBD patients have significantly increased REG expressions in the injured intestine, but with undefined mechanisms and roles. The reported functions of REG/Reg proteins in intestinal homeostasis, such as those of antibacterial, anti-inflammatory and tissue repair, lead us to discuss their potential mechanisms and clinical relevance in IBD in order to advance IBD research and management.
Core tip: The clinical management of inflammatory bowel disease (IBD) remains a significant challenge due to the knowledge gap in its pathogenesis. In this review paper, we have discussed the literature regarding increased expressions of regenerating islet-derived proteins in IBD and proposed the potential clinical relevance of these proteins based on their known protective activities in the inflamed intestine. We therefore provide insight from a new perspective in order to advance IBD research and clinical management.