Inflammatory bowel disease: mechanisms, redox considerations, and therapeutic targets.

Significance: Oxidative stress is thought to play a key role in the development of intestinal damage in Inflammatory Bowel Disease (IBD), because of its primary involvement in intestinal cells’ aberrant immune and inflammatory responses to dietary antigens and to the commensal bacteria. Recent advances: During the active disease phase, activated leukocytes generate a wide spectrum of pro-inflammatory cytokines, but also excess oxidative reactions, which markedly alter the redox equilibrium within the gut mucosa, and maintain inflammation by inducing redox-sensitive signaling pathways and transcription factors. Moreover, several inflammatory molecules generate further oxidation products, leading to a self-sustaining and auto-amplifying vicious circle, which eventually impair the gut barrier. Critical issues: The current treatment of IBD consists of long-term conventional anti-inflammatory therapy and often leads to drug refractoriness or intolerance, limiting patients’ quality of life. Immune modulators or anti-TNFα antibodies have recently been used, but all carry the risk of significant side effects and treatment poor response. Future Directions: Recent developments in molecular medicine point to the possibility of treating the oxidative stress associated with IBD, by designing a proper supplementation of specific lipids to induce local production of anti-inflammatory derivatives, as well as developing biological therapies that target selective molecules (i.e. NF-kB, NADPH oxidase, prohibitins or inflammasomes) involved in redox signaling. The clinical significance of oxidative stress in IBD is now becoming clear, and may soon lead to important new therapeutic options to lessen intestinal damage in this disease.