Although intake of ω-3 fatty acids such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) are well known to be beneficial for some cardiovascular and inflammatory diseases, their action mechanism remains elusive. Recently, we revealed that a EPA-metabolite 5,6-dihydroxy-8Z,11Z,14Z,17Z-eicosatetraenoic acid (5,6-DiHETE) represents strong anti-inflammatory reaction in animal body. We originally found that 5,6-DiHETE is produced rich in mouse inflamed colon tissue in the healing phase of colitis. Administration of 5,6-DiHETE could suppress histamine-induced vascular hyperpermeability by inhibiting intracellular Ca2+ increase in vascular endothelial cells. Following studies revealed that these bioactivities of 5,6-DiHETE is derived from antagonistic reaction against transient receptor potential vanilloid 4 (TRPV4) channels. In vivo, intraperitoneal or oral administration of 5,6-DiHETE promoted healing of mouse colitis. Interestingly, this novel anti-inflammatory lipid metabolite is contained rich in blue-back fish intestines. In summary, 5,6-DiHETE is an EPA-derived anti-inflammatory lipid mediator which promote healing of inflammation. It could be a new therapeutic tool as a fish-derived supplement.
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