Analysis of the structure and function of the epidermal barrier in patients with ichthyoses-clinical and electron microscopical investigations.

BACKGROUND: Ichthyoses are pathogenetically characterized by a pronounced disorder of the epidermal barrier. Clinically, hyperkeratosis, severe scaling and erythroderma are present on the entire integument. The time-consuming therapy includes daily baths and the application of skin care products to restore the epidermal barrier. OBJECTIVES AND METHODS: To enhance the knowledge about the structure and function of the epidermal barrier in ichthyoses, we conducted clinical, biophysical and electron microscopical measurements on 46 patients with ichthyoses, including autosomal recessive ichthyoses, keratinopathic ichthyoses, X-chromosomal-recessive ichthyosis and Netherton syndrome. RESULTS: The patients displayed a significantly decreased skin hydration along with unexpectedly low transepidermal waterloss values. Electron microscopical examinations demonstrated a severe occlusion of the epidermis by lipid remnants of skin care products in the stratum corneum. We found decreased intercellular lipid lamellae and an increased undulation of the corneocyte membrane of all ichthyoses, mostly pronounced in Netherton syndrome. The lipid profiles of ichthyoses showed decreased esterified Ω-hydroxy-sphingosine (EOS) ceramide levels. CONCLUSIONS: The results demonstrate the extent of the epidermal barrier disruption in ichthyoses. In combination with the knowledge about pathogenetic causes, individually improved therapeutic options can be derived from our results. In the future, the analyses of the organization of intercellular lipid lamellae and corneocyte membrane undulation will enable improved investigations of the epidermal barrier in ichthyoses and may be used to study and evaluate possible effects of topical skin preparations.

A plant oil-containing pH 4 emulsion improves epidermal barrier structure and enhances ceramide levels in aged skin.

OBJECTIVE: Xerosis is a serious problem among the very old. It is a dermatological challenge caused by significant alterations in stratum corneum (SC) function and structure. Two negative changes in aged skin are (i) the enhanced skin surface pH and (ii) the altered SC lipid content, composition and ordering. METHODS: Therefore, we investigated the way in which an acidic skin care product with different plant oils affects SC function, structure and lipid profile in older subjects with dry skin. Before and after a 3-week application period, different biophysical measurements were performed: transepidermal water loss, SC hydration and skin surface pH. In addition, the SC lipid matrix was evaluated by analysis of the intercellular lipid lamellae and the SC lipid profile. RESULTS: After treatment, a significant increase in lipid lamellae in the intercellular space of the SC was observed in the area treated with the test product compared to the untreated area. Furthermore, the ceramide level was found to be increased, although ceramides were not provided by the acidic test formulation. CONCLUSION: In summary, topical application of a pH 4.0 product containing plant oils improves epidermal barrier formation and SC lipid ordering and ratio in aged dry skin.