Mechanical properties and barrier function of healthy human skin

The aim of this study was to investigate the relationship between the mechanical properties and the epidermal barrier function of the skin in vivo. A suction cup device commonly used for measurement of skin mechanics was used to provide a defined stress to the skin using the ventral forearm in 16 healthy volunteers. The integrity of the barrier function was assessed by trans-epidermal water loss and skin capacitance. In the first part of the study, changes in barrier function were measured following the application of standardized strain to the skin barrier. In the second part of the study changes in skin mechanics were assessed following standardized barrier removal. The Wilcoxon signed rank test and Spearman's rank correlation were used for statistical analysis. Significant increases were established in trans-epidermal water loss (p < 0.01) with concomitant significant decreases in capacitance (p < 0.05) following 400 mbar and 600 mbar of suction, suggesting that the mechanical integrity of the skin barrier was disrupted. A significant increase in distensibility (p < 0.05) and hysteresis (p < 0.01) was found following stripping, relating the role of the skin barrier to the overall mechanical properties of the skin. This study showed that the water permeability of the epidermis was significantly affected by the application of mechanical stress to the skin and vice versa, the mechanical properties of the skin were altered when the barrier was compromised. These observations suggest that the mechanical strength of the skin barrier may play a role in the development of, for example, friction dermatitis and other skin diseases affected by mechanical stress.