The significance of polyunsaturated fatty acids in cutaneous biology.
The skin epidermis displays a highly active metabolism of polyunsaturated fatty acids (PUFA). Dietary deficiency of linoleic acid (LA) and 18-carbon (n-6) PUFA results in characteristic scaly skin disorder and excessive epidermal water loss. Arachidonic acid, a 20-carbon (n-6) PUFA is metabolized via the cyclooxygenase pathway into predominantly prostaglandin E2 (PGE2) PGF2 alpha, and PGD2 and via the lipoxygenase pathway into predominantly 15-hydroxyeicosatetraenoic acid (15-HETE). The prostaglandins modulate normal skin physiological processes at low concentrations and inflammatory reactions at high concentrations. Similarly, the very active epidermal 15-lipoxygenase transforms dihomogammalinolenic acid (DGLA) into 15-hydroxy eicosatrienoic acid (15-HETrE), eicosapentaenoic acid (EPA) into 15-hydroxyeicosapentaenoic acid (15-HEPE) and docosahexaenoic acid (DHA) into 17-hydroxydocosahexaenoic acid (17-HDoHE), respectively. These monohydroxy acids exhibit anti-inflammatory properties. In contrast, the 18-carbon (n-6) PUFA is transformed into 13-hydroxy-9,11-octadecadienoic acid (13-HODE), which exerts antiproliferative properties in the tissue. Thus, the supplementation of diets with appropriate purified vegetable oils and/or fish oil may generate local cutaneous anti-inflammatory metabolites which could serve as a less toxic in vivo monotherapy or as adjuncts to standard therapeutic regimens for the management of skin inflammatory disorders.
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Department of Dermatology, University of California, Davis, USA.
D000818:Animals; D002455:Cell Division / Q000502:physiology; D004042:Dietary Fats, Unsaturated / Q000378:metabolism / Q000494:pharmacology*; D004817:Epidermis / Q000378:metabolism*; D005231:Fatty Acids, Unsaturated / Q000378:metabolism*; D006801:Humans; D019787:Linoleic Acid; D008041:Linoleic Acids / Q000378:metabolism / Q000502:physiology; D008084:Lipoxygenase / Q000378:metabolism; D010100:Oxygen / Q000378:metabolism
D004042:Dietary Fats, Unsaturated; D005231:Fatty Acids, Unsaturated; D008041:Linoleic Acids; C024348:13-hydroxy-9,11-octadecadienoic acid; D019787:Linoleic Acid; D008084:Lipoxygenase; D010100:Oxygen