Starr Nichola J, Johnson Daniel J, Wibawa Judata, Marlow Ian, Bell Mike, Barrett David A, Scurr David J
School of Pharmacy, University of Nottingham , Nottingham, NG7 2RD, U.K.
College of Engineering, Swansea University , Swansea, SA1 8EN, U.K.
Anal Chem. 2016 Apr 19;88(8):4400-8. doi: 10.1021/acs.analchem.5b04872. Epub 2016 Apr 7.
This work demonstrates the ability to detect changes in both quantity and spatial distribution of human stratum corneum (SC) lipids from samples collected in vivo. The SC functions as the predominant barrier to the body, protecting against the penetration of xenobiotic substances. Changes to the SC lipid composition have been associated with barrier impairment and consequent skin disorders, and it is therefore important to monitor and quantify changes to this structure. This work demonstrates the first reported use of time-of-flight secondary ion mass spectrometry (ToF-SIMS) to assess physiological changes to human SC as a function of depth. This technique provides exceptional sensitivity and chemical specificity, allowing analysis of single tape stripped samples taken from volunteers. Using this methodology we were able to successfully identify chemical differences in human SC resulting from both intrinsic and extrinsic (photo) aging. Samples were collected from women of two age groups (under 27 and postmenopausal) and from two body sites with varying UV exposure (inner forearm and dorsal hand), and differences were identified using multivariate data analysis. The key finding was the significant aged-related increase and change in spatial distribution of the sterol cholesterol sulfate, a membrane stabilizing lipid. Significant changes in the prevalence of both lignoceric acid (C24:0) and hexacosanoic acid (C26:0) were also observed. This work describes previously unreported age-related chemical changes to human SC, providing an insight into aging mechanisms which may improve the design of both pharmaceutical and cosmetic topical products.
这项研究展示了从体内采集的样本中检测人角质层（SC）脂质数量和空间分布变化的能力。角质层作为身体的主要屏障，可防止外源性物质的渗透。角质层脂质组成的变化与屏障功能受损及随之而来的皮肤疾病有关，因此监测和量化该结构的变化很重要。这项研究首次报道了使用飞行时间二次离子质谱（ToF-SIMS）来评估人角质层随深度变化的生理变化。该技术具有极高的灵敏度和化学特异性，能够分析从志愿者身上采集的单条胶带剥离样本。使用这种方法，我们成功地识别了由内在和外在（光）老化导致的人角质层中的化学差异。样本取自两个年龄组（27岁以下和绝经后）的女性以及两个紫外线暴露程度不同的身体部位（前臂内侧和手背），并通过多变量数据分析确定差异。关键发现是膜稳定脂质硫酸胆固醇的含量随年龄显著增加且空间分布发生变化。同时还观察到木蜡酸（C24:0）和二十六烷酸（C26:0）的含量也有显著变化。这项研究描述了此前未报道的人角质层与年龄相关的化学变化，为老化机制提供了见解，这可能有助于改进药物和化妆品外用产品的设计。
