The concept of sphingolipid rheostat in skin: A driving force for new active ingredients in cosmetic applications

Abstract

Skin is a representative model of the complex metabolism that lipids may trigger. It is known that the biosynthesis of these lipids in mammalian cells generally ensures the cell membranes stability and participates to the signaling function. In the inner layers of the skin, the "de-novo" synthesis is the driving force ensuring proliferation, development and intercellular signaling. To promote stratum corneum formation, lipid catabolism leads to the renewal of ceramides, fatty acids and cholesterol that are responsible for the cohesion of the stratum corneum, its permeability, hydration, moisturization and signalling with the outer skin layers, appendages and inner layers secretion (cytokines, neuropeptides). Some actives applied in local treatments (i.e., peptides, n-3 polyunsaturated fatty acids (PUFA), ceramides, urea or an aqueous extract of Gromwell) and in oral treatment (i.e., sphingomyelin, n-3 polyunsaturated fatty acids (PUFA)) promote sphingosine 1-phosphate (S1P) production by the sphingolipid rheostat via triggering the salvage process along with autophagy and detoxification in aged skin. This review gives some basis for using the concept of sphingolipid metabolism rheostat in skin as the driving force for the development of new cosmetic actives ingredients or for repositioning the benefits of other actives for the skin.