STRATUM-CORNEUM LIPIDS - THE EFFECT OF AGING AND THE SEASONS

Stratum corneum lipids play a predominant role in maintaining the wate r barrier of the skin, In order to understand the biological variation in the levels and composition of ceramides, ceramide 1 subtypes, chol esterol and fatty acids, stratum corneum lipids collected from tape st rippings from three body sites (face, hand, leg) of female Caucasians of different age groups were analysed, In addition, we studied the inf luence of seasonal variation on the lipid composition of stratum corne um from the same body sites, The main lipid species were quantified us ing high-performance thin-layer chromatography and individual fatty ac ids using gas chromatography, Our findings demonstrated significantly decreased levels of all major lipid species, in particular ceramides, with increasing age, Similarly, the stratum corneum lipid levels of al l the body sites examined were dramatically depleted in winter compare d with spring and summer, The relative levels of ceramide 1 linoleate were also depleted in winter and in aged skin whereas ceramide 1 oleat e levels increased, The other fatty acid levels remained fairly consta nt with both season and age, apart from lignoceric and heptadecanoic a cid which showed a decrease in winter compared with summer, The decrea se in the mass levels of intercellular lipids and the altered ratios o f fatty acids esterified to ceramide 1, are likely to contribute to th e increased susceptibility of aged skin to perturbation of barrier fun ction and xerosis, particularly during the winter months.