The human vermilion surface contains a rich amount of cholesterol sulfate than the skin

Abstract

BackgroundThe vermilion of the human lip presents characteristic features and undergoes aging faster than the skin. Therefore, knowledge of the vermilion surface-specific functional molecules is important to understand lip aging and formulate lip care products. Previously, we analyzed the free fatty acids distributions and showed that docosahexaenoic acid highly accumulated in the vermilion's epithelium than in the skin. ObjectiveWe aimed to explore the functional molecules other than the free fatty acids on the vermilion's surface. MethodsHuman lip tissues from children and tape-stripped samples from smooth and rough lips of adults were measured by desorption electrospray ionization-mass spectrometry imaging (DESI-MSI). ResultsDESI-MSI of children's lip sections revealed a major distribution of five phospholipid species in the viable layer, but not in the superficial area, of both the vermilion and the skin than that in the underlying tissue. Interestingly, a remarkably higher distribution of cholesterol sulfate was observed in the vermilion's superficial area compared to that in the skin in all subjects under this study. Furthermore, DESI-MSI of tape-stripped lip samples showed an overall higher accumulation of cholesterol sulfate in the stratum corneum of the rough lips than that in the smooth lips. ConclusionOur study concluded that cholesterol sulfate has a characteristic distribution to the vermilion's surface and showed an association with the roughness of the lip.