School of Chemical Engineering, University of Birmingham, Birmingham, UK.
Skin Res Technol. 2023 Nov;29(11):e13507. doi: 10.1111/srt.13507.
The Stratum Corneum (SC) is the first barrier of the skin. The properties of individual cells are crucial in understanding how the SC at different anatomical regions maintains a healthy mechanical barrier. The aim of the current study is to present a comprehensive description of the maturation and mechanical properties of superficial corneocytes at different anatomical sites in the nominal dry state.
Corneocytes were collected from five anatomical sites: forearm, cheek, neck, sacrum and medial heel of 10 healthy young participants. The surface topography was analysed using Atomic Force Microscopy (AFM) and Scanning Electron Microscopy (SEM). The level of positive-involucrin cornified envelopes (CEs) and desmoglein-1 (Dsg1) were used as indirect measures of immature CEs and corneodesmosomes, respectively. In addition, AFM nanoindentation and stress-relaxation experiments were performed to characterise the mechanical properties.
Volar forearm, neck and sacrum corneocytes presented similar topographies (ridges and valleys) and levels of Dsg1 (13-37%). In contrast, cheek cells exhibited circular nano-objects, while medial heel cells were characterized by villi-like structures. Additionally, medial heel samples also showed the greatest level of immature CEs (32-56%, p < 0.001) and Dsg1 (59-78%, p < 0.001). A large degree of inter-subject variability was found for the Young's moduli of the cells (0.19-2.03 GPa), which was correlated with the level of immature CEs at the cheek, neck and sacrum (p < 0.05).
It is concluded that a comprehensive study of the mechanical and maturation properties of corneocytes may be used to understand the barrier functions of the SC at different anatomical sites.
表皮是皮肤的第一道屏障。了解不同解剖部位的表皮如何维持健康的机械屏障，关键在于单个细胞的特性。本研究旨在全面描述在名义干燥状态下，不同解剖部位的浅层角质形成细胞的成熟和机械特性。
从 10 名健康年轻参与者的五个解剖部位（前臂、脸颊、颈部、骶骨和内踝）收集角质形成细胞。使用原子力显微镜（AFM）和扫描电子显微镜（SEM）分析表面形貌。阳性内包膜（CE）的角蛋白整合素和桥粒芯糖蛋白 1（Dsg1）的水平分别作为不成熟 CE 和桥粒的间接测量指标。此外，进行 AFM 纳米压痕和应力松弛实验以表征机械特性。
屈侧前臂、颈部和骶骨的角质形成细胞具有相似的形貌（脊和谷）和 Dsg1 水平（13-37%）。相比之下，脸颊细胞呈现圆形纳米物体，而内踝细胞的特征是绒毛样结构。此外，内踝样本还表现出最高水平的不成熟 CE（32-56%，p<0.001）和 Dsg1（59-78%，p<0.001）。细胞的杨氏模量存在很大的个体间变异性（0.19-2.03 GPa），与脸颊、颈部和骶骨的不成熟 CE 水平相关（p<0.05）。
综上所述，全面研究角质形成细胞的机械和成熟特性，可用于了解不同解剖部位表皮的屏障功能。
