Our meta-analysis shows that the levels of fat-soluble vitamins are generally lower in patients with inflammatory bowel diseases and their supplementation is undoubtedly indicated.
Irritable bowel syndrome is a group of functional gastrointestinal disorders with not yet fully clarified etiology. Recent evidence suggesting that mast cells may play a central role in the pathogenesis of irritable bowel syndrome paves the way for agents targeting histamine receptors as a potential therapeutic option in clinical treatment. In this review, the role of histamine and histamine receptors is debated. Moreover, the clinical evidence of anti-histamine therapeutics in irritable bowel syndrome is discussed.
Background: GPR18 is a recently deorphanized receptor which was reported to act with several endogenous cannabinoid ligands. Here, we aimed to describe the role of GPR18 in intestinal inflammation and inflammatory pain. Methods: The anti-inflammatory activity of selective GPR18 agonist, PSB-KK-1415, and antagonist, PSB-CB5, was characterized in semi-chronic and chronic mouse models of colitis induced by 2,4,6-trinitrobenzenesulfonic acid (TNBS). The extent of inflammation was evaluated based on the macroscopic and microscopic scores, quantification of myeloperoxidase (MPO) activity, and Western blot analyses of tumor necrosis factor-α (TNF-α) and interleukin-6 in colonic tissue. The expression of GPR18 in colonic samples from patients with Crohn's disease (CD) was quantified using realtime PCR. The anti-nociceptive potential of the agonist in intestinal inflammation was evaluated in the mouse model of inflammatory pain.
Introduction
Inflammatory bowel diseases (IBD) are a group of chronic gastrointestinal tract disorders with complex etiology, with intestinal dysbiosis as the most prominent factor. In this study, we assessed the anti-inflammatory and antibacterial actions of the human cathelicidin LL-37 and its shortest active fragment, KR-12 in the mouse models of colitis.
Materials and methods
Mouse models of colitis induced by 2,4,6-trinitrobenzenesulfonic acid (TNBS) and dextran sulfate sodium (DSS) were used in the study. The extent of inflammation was evaluated based on the macro- and microscopic scores, quantification of myeloperoxidase (MPO) activity and microbiological analysis of stool samples.
Results
A preliminary study with LL-37 and KR-12 (1 mg/kg, ip, twice daily) showed a decrease in macroscopic and ulcer scores in the acute TNBS-induced model of colitis. We observed that KR-12 (5 mg/kg, ip, twice daily) reduced microscopic and ulcer scores in the semi-chronic and chronic TNBS-induced models of colitis compared with inflamed mice. Furthermore, qualitative and quantitative changes in colonic microbiota were observed: KR-12 (5 mg/kg, ip, twice daily) decreased the overall number of bacteria, Escherichia coli and coli group bacteria. In the semi-chronic DSS-induced model, KR-12 attenuated intestinal inflammation as demonstrated by a reduction in macroscopic score and colon damage score and MPO activity.
Conclusions
We demonstrated that KR-12 alleviates inflammation in four different mouse models of colitis what suggests KR-12 and cathelicidins as a whole are worth being considered as a potential therapeutic option in the treatment of IBD.
Background and Aims: Irritable bowel syndrome (IBS) is one of the most common functional gastrointestinal (GI) disorders characterized by pain and impaired bowel movements. Currently available drugs show limited efficacy. Cannabinoid 1 receptor (CB1) inverse agonists (CB1-RAN) cause diarrhea and may be candidates for the treatment of constipation-predominant IBS (IBS-C). We evaluated the effects of CB1-RAN in clinical trials for their potential use in IBS-C.
Methods: Database search identified all clinical trials published up to May 2018 that reported rimonabant and taranabant treatment for at least one month and detailed the GI adverse events (AEs). Categorical outcomes (subgroups of AEs) were analyzed using the odds ratio (OR).
Results: Eighteen trials met the inclusion criteria. Rimonabant 20 mg produced significantly more overall AEs (OR=1.35, CI: 1.19–1.52, p<0.0001), psychiatric events (OR=1.79, CI: 1.46–2.21, p<0.001) and GI AEs (OR=2.05, CI: 1.65–2.55, p<0.001) compared to placebo. Taranabant at doses ranging from 0.5 to 8 mg produced significantly more overall AEs (OR=1.36, CI: 1.13-1.64, p<0.002), psychiatric AEs (1.82, CI: 1.54–2.16, p<0.001) and GI AEs (OR=1.75, CI: 1.29–2.37, p<0.001) compared to placebo.
Conclusions: The approach to target CB1 in the gut for the treatment of IBS-C or chronic constipation seems a promising therapeutic option. Prospective clinical trials on the possible targeting of CB1 and the endocannabinoid system are warranted.
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