Dr August Wolff GmbH & Co. KG Arzneimittel, Bielefeld, Germany.
Microscopy Services Dähnhardt GmbH, Flintbek, Germany.
J Dermatol. 2019 Jun;46(6):457-465. doi: 10.1111/1346-8138.14891. Epub 2019 May 20.
The pH of the skin surface increases with age and thus reduces epidermal barrier function. Aged skin needs appropriate skin care to counterbalance age-related pH increase and improve barrier function. This confirmatory randomized study investigated the efficacy of water-in-oil (w/o) emulsions with either pH 4 or pH 5.8 in 20 elderly subjects after 4 weeks of treatment. After the treatment, the skin was challenged with a sodium dodecyl sulphate (SDS) solution in order to analyze barrier protection properties of both formulations. The pH 4 w/o emulsion resulted in a significantly lower skin pH compared with the pH 5.8 w/o emulsion and an improved skin hydration after 4-week treatment. Further, the pH 4 emulsion led to more pronounced improvements in length of intercellular lipid lamellae, lamellar organization as well as lipid levels than the pH 5.8 emulsion. Following SDS-induced barrier damage to the skin, the pH of all test areas increased, but the area treated with the pH 4 emulsion showed the lowest increase compared with baseline. In addition, even after the SDS challenge the skin area treated with the pH 4 emulsion still maintained a significantly increased length of intercellular lipid lamellae compared with the beginning of the study. This study provides evidence that topical application of a w/o emulsion with pH 4 reacidifies the skin in elderly and has beneficial effects on skin moisturization, regeneration of lipid lamellae and lipid content. Application of a pH 4 emulsion can improve the epidermal barrier as well as the stratum corneum organization in aged skin.
皮肤表面的 pH 值会随年龄增长而升高，从而降低表皮屏障功能。老化的皮肤需要适当的皮肤护理来抵消与年龄相关的 pH 值升高，并改善屏障功能。这项验证性随机研究调查了 pH 值为 4 或 5.8 的水包油 (w/o) 乳液在 20 名老年受试者中经过 4 周治疗后的疗效。治疗后，用十二烷基硫酸钠 (SDS) 溶液对皮肤进行挑战，以分析两种配方的屏障保护特性。与 pH 值为 5.8 的 w/o 乳液相比，pH 值为 4 的 w/o 乳液可使皮肤 pH 值显著降低，并在 4 周治疗后改善皮肤水合作用。此外，与 pH 值为 5.8 的乳液相比，pH 值为 4 的乳液可使细胞间脂质板层的长度、板层结构和脂质水平得到更显著的改善。在 SDS 引起皮肤屏障损伤后，所有测试区域的 pH 值均升高，但与基线相比，用 pH 值为 4 的乳液处理的区域 pH 值升高幅度最小。此外，即使在 SDS 挑战后，用 pH 值为 4 的乳液处理的皮肤区域仍保持与研究开始时相比显著增加的细胞间脂质板层长度。这项研究提供了证据，表明局部应用 pH 值为 4 的 w/o 乳液可使老年皮肤重新酸化，并对皮肤保湿、脂质板层和脂质含量的再生具有有益作用。应用 pH 值为 4 的乳液可以改善表皮屏障以及老化皮肤的角质层组织。
