Human skin equivalents (HSEs) are generated from isolated skin cells. As the primary function of the skin is to form a barrier, in this thesis the barrier properties of three HSEs were assessed and... Show moreHuman skin equivalents (HSEs) are generated from isolated skin cells. As the primary function of the skin is to form a barrier, in this thesis the barrier properties of three HSEs were assessed and compared with native human skin. The results show that all HSEs have a decreased skin barrier function compared to native human skin. Lipids in the outermost layer of the skin, the stratum corneum (SC), play a key role in this barrier function. The lipids in the HSEs are arranged in lipid lamellae, similarly as in human skin, but form a less crystalline organization. Investigation of the lipid composition reveals that all HSEs have an increased presence of mono-unsaturated fatty acids and reduced total fatty acid content compared to human SC, which most likely is responsible for the reduced density in lipid organization. Another group of lipids, the ceramides, show a comparable composition, although the HSEs have increa sed levels of acylceramides compared to native human SC. As we show that the culture conditions are of crucial importance for the SC lipid properties of HSEs, a future change is to optimize the culture conditions to improve epidermal lipid metabolism in HSEs, resulting in improved SC barrier properties Show less
