The skin barrier of melasma is involved in the pathogenesis of melasma. Previous studies have shown that there are differences in the expression of epidermal lipid genes in melasma, but little is known about the epidermis lipid composition of melasma. Compared with the non-lesional skin, the content of total lipids, phosphatidic acid, phosphatidylserine, and ceramide (Cer) increased significantly in the lesional skin. Multivariate data analysis indicated that 40 individual Cer lipid species were responsible for the discrimination. In terms of acyl chain length in Cer, the expressions of very long chain (VLC) (C20–C26) and ultra-long chain (ULC) (>C26) increased significantly in the lesional skin. However, Cer[AH] had negative correlations with the activation of melanocytes in the lesional skin. Some lipid species had lower expression in lesional skin with high activation of melanocytes, as well as the high darkness. The epidermal thickness of lesional skin was higher compared with the non-lesional skin. These results suggest that Cer increased significantly in the lesional skin of melasma, possibly as a compensatory mechanism to maintain skin barrier function. Between different groups of darkness and activation of melanocytes, the change of ceramides might have correlation with the pigmentation progress of melasma.

中文翻译：

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胶带剥离和脂质组学揭示女性黄褐斑皮肤表面脂质异常

黄褐斑的皮肤屏障参与了黄褐斑的发病机制。以往的研究表明，黄褐斑中表皮脂质基因的表达存在差异，但对黄褐斑的表皮脂质组成知之甚少。与非损伤皮肤相比，损伤皮肤中总脂质、磷脂酸、磷脂酰丝氨酸和神经酰胺（Cer）的含量显着增加。多变量数据分析表明，40 种单独的 Cer 脂质种类负责区分。就Cer中的酰基链长度而言，病变皮肤中极长链(VLC)(C20-C26)和超长链(ULC)(>C26)的表达显着增加。然而，Cer[AH]与病变皮肤黑色素细胞的活化呈负相关。一些脂质种类在病变皮肤中表达较低，黑色素细胞高度活化，以及高度黑暗。与非病变皮肤相比，病变皮肤的表皮厚度更高。这些结果表明，Cer 在黄褐斑病变皮肤中显着增加，可能是维持皮肤屏障功能的一种补偿机制。在不同的暗度和黑素细胞活化之间，神经酰胺的变化可能与黄褐斑的色素沉着进展有关。