Eicosapentaenoic acid ethyl ester ameliorates atopic dermatitis-like symptoms in special diet-fed hairless mice, partly by restoring covalently bound ceramides in the stratum corneum.

Skin barrier dysfunction has a key role in the development of atopic dermatitis (AD). Covalently bound ceramides (Cer), which are essential lipids for permeability barrier homoeostasis, are reportedly decreased in the stratum corneum (SC) of AD patients. Hairless mice fed a special diet develop pruritic dermatitis resembling human AD. Our previous study found that oral administration of the n-3 polyunsaturated fatty acid α-linolenic acid ameliorated skin barrier dysfunction in AD mice with concomitant increase in serum eicosapentaenoic acid (EPA). In this study, we examined the effects of EPA ethyl ester (EPA-E) on diet-induced AD in hairless mice. Oral administration of EPA-E ameliorated skin barrier dysfunction and pruritus in AD mice. In the SC of AD mice, covalently bound Cer were markedly diminished. EPA-E administration restored the lack of bound Cer. Our findings imply the possible therapeutic clinical application of EPA-E in the treatment of human AD.