Fatty acid profiles in various lipid fractions in the female epidermis. Does the body site and age matter?

Abstract

The epidermis forms the barrier between an organism and its external environment. Although one of the major functional elements of the epidermis is the lipid-enriched extracellular matrix, containing mainly ceramides, cholesterol (CHOL) and free fatty acids, the data are limited regarding the lipid profile in the epidermis. The aim of the study was to determine the whole profile of fatty acids (FAs) in the epidermis and to examine any dependence according to the age of the subject and the site on the epidermis. Epidermis extracts obtained from 10 adults and 6 children were analyzed by gas chromatography-mass spectrometry. In total, 74 FAs in the human epidermis were identified. We observed the highest amounts of neutral lipids (including CHOL) compared to other lipid fractions in the epidermis, regardless of age. However, we detected an age-dependent content of the major lipid fractions, where the main difference was in the levels of polyunsaturated fatty acids. There were also differences in the lipid profile between various sites of the body, e.g. samples from the breast and abdomen were enriched with very long-chain fatty acids compared to the limb. Our research provides novel data concerning the lipid profile in the epidermis, gives further insight into skin biology and proves that the epidermis is a highly dynamic structure.