Published online Aug 6, 2016. doi: 10.4292/wjgpt.v7.i3.353
Peer-review started: April 5, 2016
First decision: May 23, 2016
Revised: June 10, 2016
Accepted: July 14, 2016
Article in press: July 18, 2016
Published online: August 6, 2016
Processing time: 125 Days and 2 Hours
Inflammatory bowel diseases (IBDs), including Crohn’s disease and ulcerative colitis are complex disorders with undetermined etiology. Several hypotheses suggest that IBDs result from an abnormal immune response against endogenous flora and luminal antigens in genetically susceptible individuals. The dysfunction of the mucosal immune response is implicated in the pathogenesis of IBD. The balance between pro-inflammatory cytokines [tumor necrosis factor (TNF)-α, interleukin (IL)-1β, IL-8, and IL-17A], anti-inflammatory cytokines (IL-4 and IL-13), and immunoregulatory cytokines (IL-10 and transforming growth factors β) is disturbed. Moreover, evidence from animal and clinical studies demonstrate a positive correlation between an increased concentration of nitric oxide (NO) and the severity of the disease. Interestingly, proinflammatory cytokines are involved in the up-regulation of inducible oxide synthase (iNOS) expression in IBD. However, anti-inflammatory and immunoregulatory cytokines are responsible for the negative regulation of iNOS. A positive correlation between NO production and increased pro-inflammatory cytokine levels (TNF-α, IL-6, IL-17, IL-12, and interferon-γ) were reported in patients with IBD. This review focuses on the role of cytokines in intestinal inflammation and their relationship with NO in IBD.
Core tip: Inflammatory bowel diseases (IBDs), including Crohn’s disease and ulcerative colitis are an immunolgically mediated disease with undetermined etiology. Evidence from animal and clinical studies demonstrate a positive correlation between an increased concentration of nitric oxide (NO) and the severity of the disease. Moreover, a positive correlation between NO production and increased pro-inflammatory cytokine levels [tumor necrosis factor-α, interleukin (IL)-6, IL-17, IL-12, and interferon-γ] were reported in patients with IBD. This review focuses on the role of cytokines in intestinal inflammation and their relationship with NO in IBD.