Lipids and barrier function of the skin

The purpose of the present manuscript is to review the chemical and physica l properties of epidermal lipids and to relate these properties to the form ation and function of the permeability barrier of the skin. Lipids accumula te in small organelles known as lamellar granules as epidermal keratinocyte s differentiate, This lipid is extruded into the intercellular spaces where it undergoes enzymatic processing to produce a lipid mixture consisting of ceramides, cholesterol and fatty acids, This intercellular lipid is unique ly organized into a multilamellar complex that fills most of the intercellu lar space of the stratum corneum, The barrier properties of the stratum cor neum are related to the phase behavior of the intercellular Lipids. It has been proposed that a structurally unusual acylglucosylceramide is thought t o be involved in assembly of the lamellar granules, and a related acylceram ide may have a major influence on the organization of the lamellae in the s tratum corneum.