Phosphatidylserine-Related Lipid Alterations Are Associated with the Shift of Oily Skin Towards an Acne-Associated Unhealthy State in Young Women: A Skin Surface Lipidomic Study

BACKGROUND: Oily skin is not synonymous with acne. However, the skin surface lipid differences between healthy and acne-associated states within an oily-skin population remain insufficiently characterised. OBJECTIVES: To characterise compositional and structural differences in skin surface lipids (SSLs) between healthy and acne-associated unhealthy states among young women with oily skin. METHODS: Sixty-six women aged 18-24 years with oily skin were enrolled, including 33 with healthy oily skin and 33 with mild-to-moderate acne-associated unhealthy oily skin. SSLs were analysed by ultra-performance liquid chromatography-quadrupole time-of-flight mass spectrometry combined with multivariate analysis, with emphasis on lipid abundance, fatty acyl chain length and unsaturation. RESULTS: The two groups showed distinct SSL profiles. The acne-associated unhealthy oily skin group exhibited a lower relative abundance of saturated fatty acids, a higher relative abundance of unsaturated fatty acids and a reduced monounsaturated/polyunsaturated fatty acid ratio. Abundance-weighted mean chain lengths of fatty acids and triglycerides were reduced. Ceramides showed fatty acyl chain-length redistribution, with increased long-chain and decreased very-long-chain species. Phosphatidylserine and phosphatidylinositol were also increased. CONCLUSIONS: Acne-associated unhealthy oily skin in young women is characterised by multilayered lipid remodelling involving sebum-associated, barrier-related and membrane-associated lipids. Phosphatidylserine-related alterations may represent a candidate lipid feature associated with deviation from healthy oily skin homeostasis.