Influence of Topical Formulations: Lipid Lamella Organization and Lipid Composition of Stratum Corneum as a Surrogate Marker for Barrier Integrity.

Skin barrier repair therapies often involve the use of medicated and non-medicated topical preparations. To measure the effect of topical preparations, clinical (scoring systems, for example, Score of Atopic Dermatitis, Dermatology Quality of Life Index) and biophysical procedures (e.g., trans-epidermal water loss, skin hydration) are widely used. However, the results of these procedures describe the condition of the barrier indirectly. A direct assessment of skin barrier integrity is primarily possible by electron-microscopic examination, visualization and morphometric analysis of the lipid lamellae in the intercellular space of the stratum corneum (SC) and by quantitatively characterizing the composition of key SC lipids. Recently, the combination of a non-invasive lipid barrier visualization (Lipbarvis®) technique (SC sampling and morphometric analysis) and SC lipid composition analysis (chromatographic analysis) has been proposed to directly characterize the skin barrier integrity. Initial experience demonstrates that morphometric analysis of the lipid lamellae organization in the intercellular space of the SC as well as the characterization of the composition of key SC lipids may serve as surrogate marker to study the influence of topical non-medicated preparations including pH-lowered preparations.