Expression patterns of superficial epidermal adhesion molecules in an experimental dog model of acute atopic dermatitis skin lesions.

Abstract

BACKGROUND: The stratum corneum is critical for providing a functional skin barrier, especially in humans and dogs with atopic dermatitis. An effective barrier also depends upon intact corneodesmosomes and superficial epidermal tight junctions. HYPOTHESIS/OBJECTIVES: To study the expression of selected corneodesmosome, desmosome, tight and adherens junction proteins in an experimental model of acute atopic dermatitis skin lesions in dogs. METHODS: Control and house dust mite (HDM) allergen-containing patches (two types of patches) were applied to the skin of six Maltese-beagle atopic dogs hypersensitive to HDM. Patches were left on for 48&#xa0;h, and biopsies were collected 24&#xa0;h after removal. Frozen skin sections were stained by indirect immunofluorescence for corneodesmosin, desmoglein-1, desmocollin-1, claudin-1 and E-cadherin. Immunostains were assessed for their extent, intensity and patterns; they were compared between HDM and control patches on the same dogs. RESULTS: The immunostaining for E-cadherin, desmocollin-1 and desmoglein-1 was homogeneous, intercellular and continuous in all control and HDM patches. The immunoreactivity of corneodesmosin and claudin-1 was heterogeneous and reduced in intensity in 12 of 12 and eight of 12 HDM patches, respectively, in contrast to a normal expression seen in all control samples (Fisher's test, P&#xa0;<&#xa0;0.001). CONCLUSIONS AND CLINICAL IMPORTANCE: These observations suggest that HDM allergens, via proteolytic digestion and/or because of induced allergic inflammation, affect the expression and possible function of corneodesmosomal and tight junction proteins. Ensuing intercellular junction alterations might promote an abnormally increased penetration of allergens through the epidermis.