Research ArticleNOCICEPTION

A systems approach for discovering linoleic acid derivatives that potentially mediate pain and itch

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Sci. Signal.  22 Aug 2017:
Vol. 10, Issue 493, eaal5241
DOI: 10.1126/scisignal.aal5241

Deriving itch and pain from a fatty acid

Linoleic acid is a polyunsaturated ω−6 fatty acid that is consumed in high amounts in a typical Western diet and whose derivatives are associated with chronic inflammation and pain. Ramsden et al. identified several derivatives of linoleic acid in inflamed psoriatic lesions. One of these derivatives [9-keto-12,13-trans-epoxy-(10E)-octadecenoate] was much more abundant in itchy psoriatic lesions than in non-itchy psoriatic lesions or normal skin, and it induced scratching when injected into mice. Injection of another linoleic acid derivative [11-hydroxy-12,13-trans-epoxy-(9Z)-octadecenoate] caused rats to become more sensitive to thermal pain. Furthermore, chronic headache sufferers reported shorter headaches and more headache-free days when they reduced their dietary intake of linoleic acid, which was associated with decreased plasma concentrations of 11-hydroxy-12,13-trans-epoxy-(9Z)-octadecenoate. Identifying the receptor for these linoleic acid derivatives could reveal a potential pharmacological target to reduce pain and itch.