Do TLRs Play a Role in IBS?

Introduction The irritable bowel syndrome (IBS) is a functional gastrointestinal disorder whose pathogenesis is not completely understood. Recent studies suggest that low grade mucosal immune activation contribute to the pathopsysiology of IBS. Toll-like receptors (TLRs) are a family of pathogenrecognition receptors in the innate immune system. Materials and methods We performed a systematic review study using data from PubMed. We decided to look only for papers indexed in Pubmed, thus having at least English abstract. We searched on PubMed following keywords: irritable bowel syndrome, TLRs, inflammation. Only relevant studies were selected for analysis. Results We identified a few papers appropriate to this survey. Were measured expression of TLRs (TLR1TLR10) in the colonic mucosa and in the blood of IBS patients. Was found an increased expression of TLR2, whereas the expression of TLR4 was fluctuating in the blood. It seems that an exaggerated response to the TLR8 agonist for all cytokines investigated was seen in IBS patients. In human colonic mucosa was determinated increased expression of TLR2, 4, 5, 9 and decreased levels of TLR7, 8. Significant upregulation of TLR4 expression relative to controls were found in colonic mucosa of IBS-D, increased expression of TLR9 was found in PI-IBS and upregulation of TLR2 expression was found in IBS-M patients. TLR2 and TLR4 mRNA expression correlates significantly with duration of symptoms. Conclusions The TLRs and their subsequent cellular activation and production of messenger molecules can play a role in pathogenesis of IBS, but future research is required.