The lipids in the uppermost layer of the skin, the stratum corneum (SC), play an important role in the skin barrier function. The three main SC lipid classes are ceramides (CER), cholesterol and... Show moreThe lipids in the uppermost layer of the skin, the stratum corneum (SC), play an important role in the skin barrier function. The three main SC lipid classes are ceramides (CER), cholesterol and free fatty acids. In inflammatory skin diseases, such as atopic dermatitis and psoriasis, the SC lipid composition is altered compared to the healthy SC composition. The studies presented in this thesis focused on the effect of the CER subclass composition on the lipid organization, molecular arrangement and barrier function of the skin. First, the CER compositional changes were examined in the SC of seborrheic dermatitis patients, an inflammatory skin disease. A particular emphasis was paid to the ratio of two important CER subclasses, sphingosine CER (CER NS) and phytosphingosine CER (CER NP), and its correlation to the skin barrier. In the subsequent chapters lipid model systems with a simple CER subclass composition were used to study the influence of the CER NS: CER NP molar ratio on the barrier function and lipid organization. Show less
