ARTICLE: Alteration to the Skin Barrier Integrity Following Broad-Spectrum UV Exposure in an Ex Vivo Tissue Model.

Dynamic changes to the skin barrier’s molecular structure and ceramide profile are well-documented in skin conditions such as atopic dermatitis and psoriasis. Pathological and environmental factors have been shown to impair barrier integrity and demonstrate shifts in ceramide composition in the skin. However, the relationship between acute and prolonged sun exposure and its effects on skin barrier homeostasis is insufficiently investigated. This study aims to uncover new scientific evidence to elucidate the relationship of UV irradiation with the skin barrier using an ex vivo tissue model following simulated UVA/UVB exposure. Fresh ex vivo human skin pretreated either with or without a broad-spectrum sunscreen was exposed to either a physiological or elevated UV condition. Following eight days in culture, structural and molecular changes were evaluated. UV irradiated skin displayed epidermal cell death and altered expression of key barrier proteins. TEM analysis demonstrated disruption to adherens junctions and dissociation between tissue layers following both physiological and extensive UV exposures. An effective broad-spectrum sunscreen containing essential skin ceramides completely protected the skin from such changes. This is one of the first works demonstrating a clear correlation of altered skin barrier integrity using a physiologically relevant dose in an ex vivo tissue model. Our findings also further support the additional importance and benefits of sun protection among the consumers. J Drugs Dermatol. 20(4 Suppl):s23-28. doi:10.36849/JDD.S589D.