n-oleoylethanolamine and Colitis

Fatty acid ethanolamides acting on proliferator-activated receptor (PPAR)-α are among the endogenous lipid molecules that attenuate inflammatory processes and pain sensitivity. Whereas these properties are well-known for palmitoylethanolamide (PEA), the efficacy of oleoylethanolamide (OEA, first described as a satiety hormone synthesized in the jejunum) has been overlooked. In this study, we aimed to evaluate the effect of OEA administration in a mouse model of colitis. C57BL/6J mice were exposed to 2.5% dextran sodium sulphate (DSS) in drinking water for 5 days. Daily i.p. administration of 10 mg/kg OEA started 3 days before DSS and lasted for 12 days. The DSS-untreated control group received only ultrapure water. DSS mice treated with OEA had a significant improvement of disease score. OEA restored mRNA transcription of PPAR-α, of tight junctions and protective factors of colon integrity disrupted by DSS. The improvement correlated with significant decrease of colonic and systemic levels of pro-inflammatory cytokines compared to the DSS group. OEA antiinflammatory effects were mediated by the selective targeting of the TLR4 axis causing a downstream inhibition of nuclear factor kappa B (NF-κB)- MyD88-dependent and NLRP3 inflammation pathways. OEA treatment also inhibited DSS-induced increase of inflammatory cytokines levels in the mesenteric lymph nodes. CONCLUSIONS AND IMPLICATIONS: These results underscore the validity of OEA as a potent protective and anti-inflammatory agent in ulcerative colitis that may be exploited to broaden the pharmacological strategies against inflammatory bowel disease.

Topics: Animals; Anti-Inflammatory Agents; Colitis; Colon; Cytokines; Dextran Sulfate; Disease Models, Animal; Endocannabinoids; Immunologic Factors; Inflammation Mediators; Lymph Nodes; Male; Mice, Inbred C57BL; Myeloid Differentiation Factor 88; NF-kappa B; NLR Family, Pyrin Domain-Containing 3 Protein; Oleic Acids; Permeability; PPAR alpha; Signal Transduction; Toll-Like Receptor 4

Palmitoylethanolamide (PEA) acts via several targets, including cannabinoid CB1 and CB2 receptors, transient receptor potential vanilloid type-1 (TRPV1) ion channels, peroxisome proliferator-activated receptor alpha (PPAR α) and orphan G protein-coupled receptor 55 (GRR55), all involved in the control of intestinal inflammation. Here, we investigated the effect of PEA in a murine model of colitis.. Colitis was induced in mice by intracolonic administration of dinitrobenzenesulfonic acid (DNBS). Inflammation was assessed by evaluating inflammatory markers/parameters and by histology; intestinal permeability by a fluorescent method; colonic cell proliferation by immunohistochemistry; PEA and endocannabinoid levels by liquid chromatography mass spectrometry; receptor and enzyme mRNA expression by quantitative RT-PCR.. DNBS administration caused inflammatory damage, increased colonic levels of PEA and endocannabinoids, down-regulation of mRNA for TRPV1 and GPR55 but no changes in mRNA for CB1 , CB2 and PPARα. Exogenous PEA (i.p. and/or p.o., 1 mg·kg(-1) ) attenuated inflammation and intestinal permeability, stimulated colonic cell proliferation, and increased colonic TRPV1 and CB1 receptor expression. The anti-inflammatory effect of PEA was attenuated or abolished by CB2 receptor, GPR55 or PPARα antagonists and further increased by the TRPV1 antagonist capsazepine.. PEA improves murine experimental colitis, the effect being mediated by CB2 receptors, GPR55 and PPARα, and modulated by TRPV1 channels.

Topics: Administration, Oral; Amides; Animals; Anti-Inflammatory Agents; Benzenesulfonates; Capsaicin; Colitis; Colon; Disease Models, Animal; Endocannabinoids; Ethanolamines; Intestinal Absorption; Male; Mice, Inbred ICR; Oleic Acids; Palmitic Acids; Peroxidase; PPAR alpha; Receptor, Cannabinoid, CB1; Receptor, Cannabinoid, CB2; Receptors, Cannabinoid; RNA, Messenger; TRPV Cation Channels