Dermatophagoides farinae house dust mite allergen challenges reduce stratum corneum ceramides in an experimental dog model of acute atopic dermatitis

Abstract

Ceramides are essential stratum corneum (SC) lipids and they play a pivotal role in maintaining effective cutaneous barrier function. The present study aimed at determining the effect of a Dermatophagoides farinae house dust mite (Df-HDM) allergen challenge on SC ceramides of atopic dogs experimentally sensitized to these allergens. Six Df-HDM-sensitized atopic Maltese-beagle dogs were used. Prechallenge SC was obtained by cyanoacrylate stripping. One week later, the dogs were challenged topically with Df-HDM allergens, which resulted in mild to moderate inflammation 24 h later. Two weeks after challenge, SC of lesional and nonlesional skin was obtained. Finally, SC was collected from challenge sites 2 months after lesion resolution. The different SC lipids were quantified blindly by thin-layer chromatography. Significantly lower amounts of ceramides [AH], [AP], [AS], [NP], [EOP], [NS] and [EOS] were observed in lesional SC compared with prechallenge samples, while no significant effect was found on the amount of other lipids, including cholesterol and free fatty acids. The ceramide profile of nonlesional skin generally showed the same postchallenge reduction pattern. Ceramide amounts returned to normal within 2 months after lesion remission. These findings suggest that the allergic reactions caused by Df-HDM allergens lead to a selective reduction of SC ceramides, not only at sites of inflammation but also at sites away from those of allergen application. There is normalization of ceramide amounts after inflammation subsides. These observations suggest that the deficiency of ceramides observed in canine atopic skin occurs, at least in part, secondary to inflammation.