Accelerated barrier recovery and enhancement of the barrier integrity and properties by topical application of a pH 4 vs. a pH 5.8 water-in-oil emulsion in aged skin

BackgroundIncreased skin-surface pH is an important host-related factor for deteriorated barrier function in aged skin. ObjectivesWe investigated whether restoration of skin pH through topical application of a water-in-oil emulsion with pH 4 improved the barrier homeostasis in aged skin, and compared the effects with an identical galenic formulation with pH 5<bold></bold>8. MethodsThe effects of the test formulations on barrier recovery were investigated by repeated measurements of transepidermal water loss (TEWL) and skin pH 3 h, 6 h and 24 h after acetone-induced impairment of barrier function in aged skin. The long-term effects of the pH 4 and pH 5<bold></bold>8 emulsions were analysed by investigation of the barrier integrity and cohesion, the skin-surface pH and the skin roughness and scaliness before and after a 4-week, controlled application of the formulations. ResultsThe application of the pH 4 emulsion accelerated barrier recovery in aged skin: 3 h and 6 h after acetone-induced barrier disruption the differences in the TEWL recovery between the pH 4 treated and acetone control fields were significant. Furthermore, long-term application of the pH 4 formulation resulted in significantly decreased skin pH, enhanced barrier integrity and reduced skin-surface roughness and scaliness. At the same time points, the pH 5<bold></bold>8 formulation exerted only minor effects on the barrier function parameters. ConclusionsExogenous acidification through topical application of a water-in-oil emulsion with pH 4 leads to improvement of the skin barrier function and maintenance of the barrier homeostasis in aged skin. What's already known about this topic? Aged skin is associated with increased skin-surface pH. Increased skin-surface pH is associated with impairment of the permeability barrier function and properties. What does this study add? Normalization of the increased skin pH through topical application of a water-in-oil emulsion with pH 4 accelerates the barrier repair and enhances the barrier integrity and properties in aged skin. pH-dependent improvement of the barrier function and properties through topical application of water-in-oil emulsions with acidic pH in aged individuals in vivo has not previously been shown Linked Comment:Proksch. Br J Dermatol 2018; 179:254-255. Respond to this article