Laboratory of Cutaneous Physiopathology, San Gallicano Dermatological Institute IRCCS, Rome, Italy.
Department of Chemistry, University of Rome "Sapienza", Rome, Italy.
Sci Rep. 2018 Jul 31;8(1):11500. doi: 10.1038/s41598-018-29742-7.
The skin surface lipids (SSL) result from the blending of sebaceous and epidermal lipids, which derive from the sebaceous gland (SG) secretion and the permeability barrier of the stratum corneum (SC), respectively. In humans, the composition of the SSL is distinctive of the anatomical distribution of the SG. Thus, the abundance of sebum biomarkers is consistent with the density of the SG. Limited evidence on the influence that the SG exerts on the SC lipidome is available. We explored the differential amounts of sebaceous and epidermal lipids in areas at different SG density with lipidomics approaches. SC was sampled with adhesive patches from forearm, chest, and forehead of 10 healthy adults (8F, 2M) after mechanical removal of sebum with absorbing paper. Lipid extracts of SC were analysed by HPLC/(-)ESI-TOF-MS. In the untargeted approach, the naïve molecular features extraction algorithm was used to extract meaningful entities. Aligned and normalized data were evaluated by univariate and multivariate statistics. Quantitative analysis of free fatty acids (FFA) and cholesterol sulfate (CHS) was performed by targeted HPLC/(-)ESI-TOF-MS, whereas cholesterol and squalene were quantified by GC-MS. Untargeted approaches demonstrated that the relative abundance of numerous lipid species was distinctive of SC depending upon the different SG density. The discriminating species included FFA, CHS, and ceramides. Targeted analyses confirmed that sebaceous FFA and epidermal FFA were increased and decreased, respectively, in areas at high SG density. CHS and squalene, which are biomarkers of epidermal and sebaceous lipid matrices, respectively, were both significantly higher in areas at elevated SG density. Overall, results indicated that the SG secretion intervenes in shaping the lipid composition of the epidermal permeability barrier.
皮肤表面脂质（SSL）是皮脂和表皮脂质混合的结果，分别来自皮脂腺（SG）分泌和角质层（SC）的通透性屏障。在人类中，SSL 的组成与 SG 的解剖分布特征一致。因此，皮脂生物标志物的丰度与 SG 的密度一致。关于 SG 对 SC 脂质组学的影响，目前仅有有限的证据。我们使用脂质组学方法研究了 SG 密度不同部位的皮脂和表皮脂质的差异含量。在 10 名健康成年人（8 名女性，2 名男性）中，用粘性贴片从前臂、胸部和前额采集 SC 样本，用吸油纸去除皮脂后，用粘性贴片采集 SC。用 HPLC/（-）ESI-TOF-MS 分析 SC 脂质提取物。在非靶向方法中，使用原始分子特征提取算法提取有意义的实体。通过单变量和多变量统计方法评估对齐和归一化的数据。通过靶向 HPLC/（-）ESI-TOF-MS 对游离脂肪酸（FFA）和胆固醇硫酸盐（CHS）进行定量分析，而胆固醇和角鲨烯则通过 GC-MS 定量。非靶向方法表明，许多脂质种类的相对丰度根据不同的 SG 密度而具有特征性。有区别的物种包括 FFA、CHS 和神经酰胺。靶向分析证实，在 SG 密度高的区域，皮脂 FFA 增加，表皮 FFA 减少。分别作为表皮和皮脂脂质基质生物标志物的 CHS 和角鲨烯在 SG 密度升高的区域均显著升高。总的来说，结果表明 SG 的分泌干预了表皮通透性屏障的脂质组成。
