The effect of ceramide head group on the lipid organization in the long periodicity phase of stratum corneum substitutes

The barrier function of the skin is located in its uppermost layer, the stratum corneum (SC). This consists of corneocytes surrounded by an intercellular lipid matrix. This lipid domain forms the only continuous pathway through the SC and it is the main system for the barrier function. The lipid classes in SC are ceramides (CER), cholesterol and free fatty acids. Skin diseases such as atopic dermatitis or psoriasis have an impaired skin barrier and are reported to exhibit differences in lipid composition compared to healthy skin, such as a reduction of the concentration of phytosphingosine CERs (CER NP) and an increase of sphingosine CERs (CER NS and AS). We aim to study the effect of an additional hydroxyl group in the CER head group region on the localization of CER NP in the LPP and whether an increased ratio of CER NS(AS)/NP will change the location of the deuterated CER NS and NP.