Quantitative lipidomics profiling of skin surface lipids and skin barrier function evaluation in patients with acne vulgaris.

Sebum composition may be more important than amount for acne lesions, and current research on skin surface lipids (SSLs) focuses on determining their relative content. The objective of this study was to analyze the changes in the absolute content of SSLs in acne patients and their relationship with skin barrier function. To evaluate skin barrier function, transepidermal water loss (TEWL), skin moisture, sebum content, skin elasticity, and whiteness were measured, while SSL changes were investigated using LC-MS/MS. The results indicated that adult acne patients have reduced skin barrier function, as demonstrated by changes in skin moisture, sebum content, skin flexibility, and whitening. Notably, AGlcSiE, Cer, CL, Co, LPC, PA, PC, PE, PI, SM, So, SQDG, and TG were considerably enhanced in acne patients' SSLs, whereas CerG1, DG, DGDG, MGDG, PG, and phSM were decreased. Furthermore, side chain analysis showed that the ratio of linoleic acid to linolenic acid in acne patients' skin surface lipids was higher than in healthy controls, and the caprylic acid/capric acid ratio was likewise greater. The correlation study of SSLs and skin barrier function demonstrated that increasing LPC and decreasing PG are associated with skin barrier function deterioration. In conclusion, acne patients have compromised skin barrier function and altered SSL absolute content, and certain SSL species identified in this study could serve as potential targets for research into acne pathogenesis.