5s-12r-18r-trihydroxy-6z-8e-10e-14z-16e-eicosapentaenoic-acid and Hypersensitivity

Resolvins (RvD1, RvD2 and RvE1) are endogenous anti-inflammatory lipid mediators that display potent analgesic properties in somatic pain by modulating transient receptor potential vanilloid 1 (TRPV1) activation. To what extent these molecules could also have a beneficial effect on TRPV1 sensitisation and visceral hypersensitivity (VHS), mechanisms involved in IBS, remains unknown.. The effect of RvD1, RvD2 and RvE1 on TRPV1 activation and sensitisation by histamine or IBS supernatants was assessed on murine dorsal root ganglion (DRG) neurons using live Ca. RvD1, RvD2 and RvE1 prevented histamine-induced TRPV1 sensitisation in DRG neurons at doses devoid of an analgesic effect. Of note, RvD2 also reversed TRPV1 sensitisation by histamine and IBS supernatant. This effect was blocked by the G protein receptor 18 (GPR18) antagonist O-1918 (3-30 µM) and by pertussis toxin. In addition, RvD2 reduced the capsaicin-induced Ca. Our data suggest that RvD2 and GPR18 agonists may represent interesting novel compounds to be further evaluated as treatment for IBS.

Topics: Adult; Animals; Capsaicin; Disease Models, Animal; Docosahexaenoic Acids; Eicosapentaenoic Acid; Enterobacteriaceae Infections; Female; Ganglia, Spinal; Histamine; Humans; Hypersensitivity; Inflammation; Irritable Bowel Syndrome; Male; Mice; Middle Aged; Neurons; Rats; Receptors, Cannabinoid; TRPV Cation Channels

Endogenous mediators, such as RvE1 (resolvin E1), promote resolution of an inflammatory response and have potential as novel therapeutic agents. In the present study, we investigated the activity of RvE1 in a model of an acute exacerbation of chronic allergic asthma in mice. Animals sensitized to OVA (ovalbumin) received controlled low-level challenge with aerosolized antigen for 4 weeks, followed by a single moderate-level challenge to simulate an allergen-induced exacerbation of asthmatic inflammation. Induction of an exacerbation was associated with rapid recruitment of neutrophils, lymphocytes and eosinophils, together with increased levels of Th2 and pro-inflammatory cytokines. When administered before the final moderate-level challenge, RvE1 had only a modest effect on airway inflammation. To assess its effects when administered after induction of an exacerbation, we first characterized the cellular and molecular events associated with spontaneous resolution of airway inflammation over the following 96 h. Subsequently, we showed that administration of RvE1 at 2 and 8 h after the final challenge accelerated this process significantly. Specifically, RvE1 promoted a decline in the number of inflammatory cells, concentration of cytokines in lavage fluid and expression of mRNA for cytokines by macrophages, confirming its pro-resolution activity. In vitro, RvE1 had no apparent effect on lymphocytes, but suppressed significantly cytokine production by pulmonary macrophages, with evidence of down-regulation of the nuclear translocation of NF-κB (nuclear factor κB) p65 in these cells. The present study provides novel evidence that RvE1 can facilitate resolution of airway inflammation in a clinically relevant model of an acute exacerbation of asthma, possibly via its effects on activated pulmonary macrophages.

Topics: Active Transport, Cell Nucleus; Animals; Asthma; Bronchial Hyperreactivity; Bronchoalveolar Lavage Fluid; Cell Line; Cytokines; Disease Models, Animal; Eicosapentaenoic Acid; Female; Hypersensitivity; Immunohistochemistry; Inflammation; Leukocytes; Macrophages; Mice; Mice, Inbred BALB C; NF-kappa B; Ovalbumin; RNA, Messenger; Time Factors