Changes in skin barrier function following single and repeated applications of 4 types of moisturizers: a randomized controlled trial

The Skin Barrier and Moisturization: Function, Disruption, and Mechanisms of Repair

BACKGROUND

The anatomic layers of the skin are well-defined, and a functional model of the skin barrier has recently been described. Barrier disruption plays a key role in several skin conditions, and moisturization is recommended as an initial treatment in conditions such as atopic dermatitis. This review aimed to analyze the skin barrier in the context of the function model, with a focus on the mechanisms by which moisturizers support each of the functional layers of the skin barrier to promote homeostasis and repair.

SUMMARY

The skin barrier is comprised of four interdependent layers - physical, chemical, microbiologic, and immunologic - which maintain barrier structure and function. Moisturizers target disruption affecting each of these four layers through several mechanisms and were shown to improve transepidermal water loss in several studies. Occlusives, humectants, and emollients occlude the surface of the stratum corneum (SC), draw water from the dermis into the epidermis, and assimilate into the SC, respectively, in order to strengthen the physical skin barrier. Acidic moisturizers bolster the chemical skin barrier by supporting optimal enzymatic function, increasing ceramide production, and facilitating ideal conditions for commensal microorganisms. Regular moisturization may strengthen the immunologic skin barrier by reducing permeability and subsequent allergen penetration and sensitization.

KEY MESSAGES

The physical, chemical, microbiologic, and immunologic layers of the skin barrier are each uniquely impacted in states of skin barrier disruption. Moisturizers target each of the layers of the skin barrier to maintain homeostasis and facilitate repair.

Tolerability and efficacy assessment of an oral collagen supplement for the improvement of biophysical and ultrasonographic parameters of skin in middle eastern consumers

BACKGROUND

Topical skin care products often do not reach the deeper layers of the skin, and oral hydrolyzed collagen is one of the newest and most popular systemic supplementations for skin rejuvenation. However, there are limited information in case of Middle Eastern consumers OBJECTIVE: The purpose of this study was to evaluate the tolerability and efficacy of an oral collagen supplement for improvement of skin elasticity, hydration, and roughness in Middle Eastern consumers.

METHODS AND MATERIALS

It was a 12-week, before-after clinical study, conducted on 20 participants (18 women and 2 men) aged 44.15 ± 5.36 years with skin type III-IV. Skin elasticity parameters (R0, R2, R5, and R7), skin hydration and friction, as well as the thickness and echo density of the dermis, were measured after six and 12 weeks daily intake of the study product, as well as 4 weeks after stopping its use (week 16). Participants' satisfaction was assessed on the basis of their answers to the standard questionnaire, and tolerability of the product was assessed by monitoring the adverse effects.

RESULTS

A significant improvement was detected in R2, R5, and skin friction at week 12 (p-values 0.041, 0.012 and <0.01, respectively). At week 16, the values remained at an increased level, which indicates the persistence of the results. The increase of dermis density in week 16 was also significant (p-value = 0.03). Moderate overall satisfaction was reported with the treatment, and a few gastrointestinal complications were reported.

CONCLUSION

The study demonstrated that oral collagen peptides could significantly improve the skin elasticity, roughness, and dermis echo density, and they also proved to be safe and well-tolerated.

Long-term effects of two 24-hour moisturizing products on skin barrier structure and function: A biometric and molecular study

INTRODUCTION

Recently, there are a few moisturizers showing hydrating effects up to 24 hours after single application. Aquaporin 3 might be associated with the degree of skin hydration. We aimed to assess the effects of two brands of 24-hour moisturizers on the skin barrier function, as well as the AQP3 gene expression.

METHOD

Two moisturizers were applied once daily by 20 participants age 36.15 ± 9.55 years. Upper right and left forearms were randomly assigned to application of each product, whereas the right lower forearm served as control site for application of a cream base formulation. Biophysical assessments including trans epidermal water loss (TEWL), skin hydration, pH, surface lipids, and elasticity parameters were performed before intervention, 1, 4, and 24 hours after single application, following 2 weeks daily application and 1 week after termination of use. Also 5-mm punch biopsies were performed from application sites of product B and cream base formulation in for five participants after 2 weeks of application.

RESULTS

A single treatment with both products led to 24-hour increase in skin moisture in comparison with the control site (P-value <.01). Daily application of both products for 14 days also led to significant improvement in skin moisture (P-value <.01), TEWL (P-value <.01), and elasticity parameters. The increase in skin hydration was associated with upregulation of AQP3 gene expression in treated area for one of the formulations (P-value = .04).

CONCLUSION

The tested 24-hour moisturizers only need to be applied once daily to improve skin barrier function and hydration and up-regulate AQP3 mRNA expression.

Epidermal Barrier Function and Skin Homeostasis in Skin with Permanent and Adhesive Tattoos: A Cross-Sectional Study

Tattoos are a current trend, but their impact on skin homeostasis and epidermal barrier function is not well known. So, the aims of this study are (1) to investigate epidermal barrier function and skin homeostasis in skin with permanent tattoos, adhesive temporary tattoos and non-tattooed skin, and (2) to analyze the effect of petrolatum on skin with permanent and adhesive tattoos. In total, 67 tattoos were enrolled (34 permanent tattoos and 33 adhesive tattoos). Temperature, transepidermal water loss (TEWL), stratum corneum hydration (SCH), erythema and total antioxidant capacity (TAC) were measured in skin with permanent tattoos, adhesive tattoos and non-tattooed skin before and after petrolatum application. The temperature was lower (30.47 °C vs. 31.01 °C; p = 0.001) on skin with permanent tattoos than non-tattooed skin, while SCH (48.24 Arbitrary Units (AU) vs. 44.15 AU; p = 0.008) was higher. Skin with adhesive tattoos showed lower temperature, SCH (21.19 AU vs. 41.31 AU; p < 0.001) and TAC (1.27 microcoulombs (uC) vs. 3.48 uC; p < 0.001), and higher TEWL (8.65 g/h/m² vs. 6.99 g/h/m²; p = 0.003), than non-tattooed skin. After petrolatum application, the temperature decreased on skin with permanent tattoos, and TEWL and SCH decreased on skin with adhesive tattoos. Adhesive tattoos may affect skin barrier function, while permanent tattoos may have a lower impact. Tattooed and non-tattooed skin responds in different ways to moisturizers.