Effects of petrolatum, a petrolatum depositing body wash and a regular body wash on biomarkers and biophysical properties of the stratum corneum.

BACKGROUND: An important trend in the personal care industry involves the development of body wash products that not only clean the skin without damage but deposit conditioning ingredients to improve skin barrier function. OBJECTIVE: The objective of this study was to develop skin biomarker measures to quantify the treatment effects of body wash products. METHODS: We employed analysis of structural proteins (keratin 1,10,11 and involucrin), a natural moisturizing factor (pyrrolidone carboxylic acid) and an inflammatory mediator (IL-1ra/IL-1α) from adhesive discs with dry skin grading, TEWL and capacitance measurements to compare the effects of direct application of petrolatum, a high petrolatum depositing body wash, and a regular body wash on dry leg skin in a standard leg-wash treatment protocol. RESULTS: High depositing body wash and petrolatum had positive effects on stratum corneum barrier function as judged by biomarker analysis, biophysical measurements and skin grading compared to the regular body wash product. CONCLUSIONS: The results clearly indicate that a combination of biomarker and biophysical property measurements is effective for determining the skin benefits of moisturizing body wash products.

CONTEXTE: Une tendance importante dans l'industrie des soins personnels inclut le développement de produits de lavage corporel qui non seulement nettoient la peau sans l'endommager, mais déposent des ingrédients de traitement pour améliorer la fonction de la barrière cutanée. OBJECTIF: L'objectif de cette étude était de développer des mesures de biomarqueurs cutanés permettant de quantifier les effets du traitement des produits de lavage corporel. MÉTHODES: Nous avons utilisé l'analyse de protéines structurelles (kératine 1,10,11 et involucrine), un facteur hydratant naturel (acide carboxylique de pyrrolidone) et un médiateur inflammatoire (IL-1ra/IL-1a) provenant de disques adhésifs avec cotation de la sécheresse cutanée, mesures de perte d'eau transépidermique (transepidermal water loss, TEWL) et de capacitance pour comparer les effets de l'application directe de vaseline, d'un produit de lavage corporel avec dépôt élevé de vaseline et d'un produit de lavage corporel ordinaire sur la peau sèche des jambes, dans un protocole de traitement de lavage des jambes standard. RÉSULTATS: Le produit de lavage corporel à dépôt élevé et la vaseline avaient des effets positifs sur la fonction de barrière de la couche cornée, comme évalué par l'analyse des biomarqueurs, les mesures biophysiques et la cotation de la peau, comparé au produit de lavage corporel ordinaire. CONCLUSIONS: Les résultats indiquent clairement qu'une combinaison de mesures des biomarqueurs et des propriétés biophysiques est efficace pour déterminer les bienfaits pour la peau des produits de lavage corporel hydratants.

Clinical Skin Mildness Evaluations of Direct and Indirect Exposure to Two Commercial Laundry Detergents with Markedly Different pH Designed for Sensitive Skin Using a Hand-Laundering Model.

The skin mildness of two commercial laundry detergents designed for sensitive skin, Tide Free and Gentle® (TFG) versus All Free Clear® (AFC), was compared in clinical studies, and the role of marked product pH differences was assessed. Two double-blind randomized human studies were conducted. Study 1 was a 1-day repeat insult forearm test, in which four exposures to solutions of TFG or AFC were performed to mimic direct exposure to dilute detergent during hand-laundering. Corneometer, erythema and dryness grading, transepidermal water loss (TEWL), and skin surface pH evaluations were carried out. Study 2 was a 21-day arm patch test of fabrics washed with TFG or AFC to mimic indirect contact to skin of detergent residues, with erythema grading. Separately, pH and reserve alkalinity were determined for each detergent. In Study 1, TFG was significantly milder than AFC in all measures except TEWL (no significant difference). In Study 2, the detergents were approximately equivalent in erythema grading. Analysis showed AFC was substantially more alkaline (pH 10.8) than TFG (pH 7.9) with higher reserve alkalinity. TFG was significantly milder than AFC in Study 1, which may be due in part to the increased skin surface pH seen with direct exposure to AFC's high alkalinity.

Effects of season stratum corneum barrier function and skin biomarkers.

The skin on the lower legs of 25 female subjects was evaluated first in the winter, and then again in the summer of the same subjects. Barrier function was determined by measuring transepidermal water loss (TEWL), and skin hydration and dryness were evaluated by electrical measurements (Corneometer ® CM825) and visual grading. Stratum corneum (SC) was sampled using 10 sequential D-Squame sampling discs and analyzed for 2-pyrrolidone-5-carboxylic acid (PCA), keratin-1,10,11, interleukin 1α (IL-1α), interleukin 1 receptor antagonist (IL-1ra), selected ceramides, cholesterol, cholesterol sulfate, and selected free fatty acids. TEWL as well as the visual dryness grades were significantly lower in the summer while hydration was higher. PCA was significantly higher in the summer as were the keratins. The ratio IL-1ra:IL-1α, an indicator of skin inflammation, was significantly lower in the summer. The amount of protein removed by the tape strips was also significantly lower in summer indicating better SC cohesion. Among the SC lipids measured, total ceramides, individual ceramides, total fatty acids, and cholesterol were higher in summer compared to winter. Stearic acid and cholesterol sulfate were not significantly different between winter and summer.

Two randomized, controlled, comparative studies of the stratum corneum integrity benefits of two cosmetic niacinamide/glycerin body moisturizers vs. conventional body moisturizers.

BACKGROUND AND OBJECTIVE: Despite numerous body moisturizers being available, cosmetic xerosis continues to be a leading skin problem for consumers. We performed two 35-day studies to evaluate the ability of a variety of body moisturizers containing various levels of oils/lipids, humectants, as well as other ingredients (e.g., niacinamide) to improve stratum corneum integrity. METHODS: 63 and 58 female subjects were enrolled and randomized in an incomplete block design to six of nine products (eight moisturizers or no treatment control) in studies 1 and 2, respectively. The primary endpoints included visual dryness by a qualified skin grader, skin hydration as measured by Corneometer, and barrier integrity as measured by transepidermal water loss (TEWL). The primary comparisons for the two niacinamide/glycerin moisturizers were to the other six moisturizers and to the no treatment control for each endpoint. RESULTS: The two niacinamide/glycerin moisturizers demonstrated an overall better solution towards rapid and prolonged improvement of cosmetic xerosis due to functional improvement of stratum corneum barrier function compared to no treatment and the other moisturizers tested. CONCLUSIONS: These studies establish the benefit of including niacinamide in a body moisturizer to improve the integrity of the stratum corneum and thus reduce cosmetic xerosis over time.