EEMCO guidance for the assessment of stratum corneum hydration: electrical methods

Barrier damaging effects of n-propanol in occlusion-modified tandem repeated irritation test: Modulation by exposure factors and atopic skin disease

BACKGROUND

Recent studies provide evidence for significant and previously underestimated barrier damaging effects of repeated exposure to 60% n-propanol in healthy skin in vivo.

OBJECTIVES

To investigate further the cumulative effects of a range of n-propanol concentrations relevant at the workplace in healthy and atopic dermatitis (AD) individuals, and study the modulation of the outcomes by co-exposure and host-related factors.

METHODS

Healthy adult and AD volunteers were exposed to n-propanol concentrations from 30% to 75% in occlusion-modified tandem repeated irritation test with measurements of erythema, transepidermal water loss, capacitance, and the natural moisturizing factor (NMF) levels at baseline and after 96 hours.

RESULTS

n-Propanol exerted significant barrier damaging effects even at the lowest concentration in both groups. Exposure to all n-propanol concentrations significantly reduced the NMF levels. Preceding low-grade trauma by occlusion/water exposure reduced the skin irritation threshold in both groups. The differences in the severity of the barrier function impairment after exposure to the same concentrations under the same conditions between the AD and control groups were significant.

CONCLUSIONS

The negative effects of cumulative exposure to n-propanol in healthy and atopic skin shown in the study suggest the need for critical re-evaluation of its irritant properties in vivo.

Effects of lactobionic acid peel, aluminum oxide crystal microdermabrasion, and both procedures on skin hydration, elasticity, and transepidermal water loss

BACKGROUND

Topical applications of alpha-hydroxy acids and poly hydroxy acids in the form of peels gained popularity. To enhance the effect of these substances, aluminum oxide crystal microdermabrasion can be used in one procedure.

AIMS

The assessment of skin hydration, elasticity, and TEWL after using lactobionic acid in the form of 20% peel and lactobionic acid in the form of 20% peel combined with aluminum oxide crystal microdermabrasion.

MATERIAL AND METHODS

The study involved 20 Caucasian female subjects. Six treatments were performed at weekly intervals, using the Split face method-20% LA was used on the left side of the face and aluminum oxide crystal microdermabrasion followed by 20% LA application on the right side of the face.

RESULTS

Corneometric measurement showed statistically significant differences between the hydration level for sessions 1 and 3 and 1 and 6. A higher hydration level was found on the side with the combined procedure. Tewametric measurement showed that the TEWL values were different for sessions 1 and 3 and 1 and 6-they decreased. There were no statistically significant differences between the two procedures. The cutometric measurement indicated statistically significant differences between skin elasticity for pairs in session 1 and 3 and 1 and 6.

CONCLUSIONS

The results of the study indicate that the combination of LA peel with microdermabrasion increases its moisturizing effect and improves skin elasticity. The use of both procedures also contributed to the decrease in TEWL; however, greater exfoliation of the epidermis in combined procedures resulted in slightly higher TEWL values.

Flexible graphene photodetectors for wearable fitness monitoring

Wearable health and wellness trackers based on optical detection are promising candidates for public health uses due to their noninvasive tracking of vital health signs. However, so far, the use of rigid technologies hindered the ultimate performance and form factor of the wearable. Here, we demonstrate a new class of flexible and transparent wearables based on graphene sensitized with semiconducting quantum dots (GQD). We show several prototype wearable devices that are able to monitor vital health signs noninvasively, including heart rate, arterial oxygen saturation (SpO2), and respiratory rate. Operation with ambient light is demonstrated, offering low-power consumption. Moreover, using heterogeneous integration of a flexible ultraviolet (UV)-sensitive photodetector with a near-field communication circuit board allows wireless communication and power transfer between the photodetectors and a smartphone, offering battery-free operation. This technology paves the way toward seamlessly integrated wearables, and empowers the user through wireless probing of the UV index.

Facial skin mapping: from single point bio-instrumental evaluation to continuous visualization of skin hydration, barrier function, skin surface pH, and sebum in different ethnic skin types

Dry skin is one of the most important concerns of consumers worldwide. Despite huge efforts over several decades, the personal care industry still does not offer a perfect solution to satisfy the unmet needs of consumers for moisturising treatments in different ethnic groups. The paucity of data for the underlying cellular and biochemical problems in, and the effects of moisturisers on photodamaged facial skin may partly explain this. Mainly, single point measurements are used to understand the effects of products on skin physiology even on surrogate skin sites such as the non‐photodamaged volar forearm. Some groups have developed discontinuous facial maps of skin biophysical properties, however, in 2014 a continuous facial analysis of bio‐instrumental evaluations was developed using a heat map approach. These maps enabled a continuous visualization of features that not only revealed an unexpected complexity of facial skin but also indicated that use of surrogate skin sites for facial skin is inappropriate. We have demonstrated that remarkable gradients of skin hydration, TEWL, skin surface pH and sebum exist within short distances across the face and the gradients are distinctive among different ethnic groups. In addition, these studies have demonstrated that darkly‐pigmented individuals do not necessarily have a better skin barrier function than their less‐pigmented counterparts and that Caucasians have a lower facial skin surface pH compared with more pigmented subjects. Overall, there are no correlations between capacitance, TEWL and skin surface pH including individual topology angle values. Novel 3D camera approaches have also been used to facilitate a more precise assignment of measurement sites and visualisation. The 3D facial colour mappings illustrated precisely the local moisturising effects of a moisturising cream. There were subtle ethnic differences in efficacy that may be related to underlying skin biochemistry and/or ethnic differences in product application. A placebo‐controlled study using conductance measurements in Chinese subjects is also reported. Finally, a new whole face statistical approach has been taken to prove differences in skin parameters but also of moisturiser treatment that adds further to our understanding of the ethnic differences in skin physiology and product application. This paper reviews the background of the development and application of this methodology.

Effects of Facial Threading on Female Skin Texture: A Prospective Trial with Physiological Parameters and Sense Assessment

BACKGROUND

Facial threading is a common tradition in Taiwan, Southeast Asia (called "Bande Abru"), Middle East (called "Khite"), and Egypt (called "Fatlah"). In addition to the ability to remove facial vellus hairs, facial threading can make the skin fairer and shinier. However, there has been a lack of hard evidence regarding the effects of facial threading on the skin.

OBJECTIVE

To examine the effects of facial threading on skin physiology as well as visual and touch senses by using scientific instruments.

METHODS

A total of 80 participants were allocated to receive facial threading, application of powder only, exfoliation, and shaving. Prior to and following the assigned treatment, a noninvasive skin condition detection device was used to measure skin coarseness, hydration, melanin, and erythema index. Sense assessment and image analysis were also performed.

RESULTS

This study showed that facial threading was found to improve the facial skin roughness indices with significant decreases by 30.4%, 35.9%, and 16.7%, respectively, for the participants' forehead, cheek, and mouth corner skin. No significant adverse changes in moisture levels and skin pigment indices were detected. In addition, there was improvement in subjects' touch sense of their skin and feelings about skin color.

CONCLUSIONS

Traditional facial threading can remove facial vellus hairs and lower skin roughness levels, thereby improving the skin texture. However, pricking sensation appeared during the facial threading process, which might cause concerns about irritation.

Noninvasive analysis and minimally invasive in vivo experimental challenges of the skin barrier

In this review, we aim to give a concise and selective overview of noninvasive biophysical analysis techniques for skin barrier analysis (transepidermal water loss, electrical methods, confocal Raman microspectroscopy, sebumeter, reflectance spectrophotometry, tristimulus colorimetry, diffuse reflectance spectroscopy and reflectance confocal microscopy), including advantages and limitations. Rather than giving an exhaustive description of the many techniques currently available, we show the usefulness of a representative selection of techniques in the functional and morphological evaluation of the skin barrier. Furthermore, we introduce human minimally invasive skin challenging models as a means to study the mechanisms regulating skin homoeostasis and disease and subsequently show how biophysical analysis techniques can be combined with these in vivo skin challenging models in the functional and morphological evaluation of the skin barrier in healthy human skin. We are convinced that the widespread application of biophysical analysis techniques in dermatological practice and in cosmetic sciences will prove invaluable in offering personalized and noninvasive skin treatment solutions. Furthermore, combining the human in vivo challenging models with these novel noninvasive techniques will provide valuable methodology and tools for detailed characterization of the skin barrier in health and disease.

Clinical evidence of the efficacy and safety of a new 3-in-1 anti-aging topical night serum-in-oil containing melatonin, bakuchiol, and ascorbyl tetraisopalmitate: 103 females treated from 28 to 84 days

BACKGROUND

Topical melatonin is a potent antioxidant, yet there have been few clinical studies on its anti-aging effects on the skin.

OBJECTIVES

To clinically assess the anti-aging efficacy and safety of a new 3-in-1 night facial serum (NFS) combining melatonin with bakuchiol, a novel retinol-like ingredient, and ascorbyl tetraisopalmitate, in all skin types.

METHODS

Five clinical studies were performed, with a total of 103 subjects treated from 28 to 84 days. Under dermatologist supervision, a 3-month efficacy and safety study evaluated anti-aging properties by clinical scoring and instrumental evaluations. Two studies evaluated skin hydration properties for 12 hours after a single application of NFS. Two studies were performed in oily skin: a 1-month efficacy and safety study and a 1-month comedogenesis study.

RESULTS

After 12 weeks, clinical evaluation showed a statistically significant decrease in wrinkles (11%), an increase in skin firmness (8%), a reduction in redness (70%; P < 0.01 for all), and an overall improvement in skin quality and complexion. The reduction in wrinkles and the increase in skin firmness were also supported by instrumental evaluations (Dermatop and Dynaskin). Hydration levels increased significantly from 30 minutes until 12 hours and transepidermal water loss significantly decreased after 4H and 6H. Subjects favorably evaluated the efficacy and cosmetic properties of the serum, and it was well tolerated in all skin types including oily skin.

CONCLUSIONS

This 3-in-1 NFS showed significant clinical anti-aging effects when applied once daily and was well tolerated.

Ameliorative effect of tranexamic acid on physiological skin aging and its sex difference in mice

An effective method to protect the skin from natural aging is unknown. Therefore, in this study, we examined the ameliorative effects of tranexamic acid on natural skin aging. In addition, we examined the sex difference in the effect exhibited by tranexamic acid. We bred hairless mice without ultraviolet ray irradiation and physical stress for 2 years. During the study period, mice were orally administered tranexamic acid (12 mg/kg/day) three times per week. Development of signs of skin aging was found to be ameliorated by tranexamic acid. Furthermore, synthetic inhibition of plasmin was observed following tranexamic acid treatment. The synthetic reinforcement of hyaluronic acid by an increase in the number of epidermal cells and the degradative inhibition of extracellular matrix (ECM) by matrix metalloproteinase (MMP) suppression were observed. These results indicate that natural skin aging was ameliorated by tranexamic acid via the regulation of the plasmin/TGF-β/epidermal cells/hyaluronic acid and plasmin/MMPs/ECM signal transmission pathways. Taken together, sex difference was observed for the ameliorative effect of tranexamic acid on skin aging, with a stronger effect observed in females than in males. More importantly, we found that the synthesis of hyaluronic acid was stronger in female mice than in male mice.

Enhancing SKIN health and safety in aged CARE (SKINCARE Trial): a study protocol for an exploratory cluster-randomized pragmatic trial

BACKGROUND

Aged long-term care receivers are affected by various adverse skin conditions like pressure ulcers, incontinence-associated dermatitis, dryness, intertrigo, and many more. Prevention of these skin problems and the provision of general hygiene and skin care activities are key areas of nursing practice. Numerous condition-specific guidelines are available and are implemented separately. On the other hand, there is huge overlap in terms of etiology, pathogenesis, and prevention of the skin conditions mentioned above. This leads to fragmented practice neglecting shared etiologies and prevention and treatment principles.

METHODS

The overall aims of this trial are to test the feasibility and to estimate possible effects of the implementation of a comprehensive skin care and prevention strategy targeting main nursing-relevant skin problems at the same time. A two-arm cluster-randomized controlled trial will be performed in 20 nursing homes randomly selected from the population of nursing homes of the state of Berlin, comparing skin care according to the skin care and prevention strategy with standard skin care.

DISCUSSION

It is expected that the implementation of this evidence-based skin care and prevention strategy will reduce the incidence of pressure ulcers, incontinence dermatitis, and other skin problems frequently related to care dependency. This trial will benefit individual patients and aged nursing home residents in general given the high prevalence and incidence of the addressed skin conditions. Findings of this exploratory trial may lay the foundation for a change in the development and evaluation of clinical standards and practices in general as it moves the perspective from individual conditions to a more comprehensive view on overlapping or coexisting health problems, in this case common skin conditions, in old-age long-term care receivers.

TRIAL REGISTRATION

The study is registered at the German Clinical Trials Register https://www.drks.de/drks_web/navigate.do?navigationId=trial.HTML&TRIAL_ID=DRKS00015680 (Deutsches Register Klinischer Studien, or DRKS; registration number: DRKS00015680 , date of registration: January 29, 2019) and ClincialTrials.gov (registration number: NCT03824886 , date of registration: January 31, 2019).

Skin characterization and immediate effects of different dermocosmetic treatments in French and Brazilian skin

BACKGROUND

All over the world, people face the same skin problems. However, their skin characteristics are different. Thus, it is a challenge to prescribe treatments that will be effective on different skin types. Therefore, it is very important to consider the skin biology when indicating a dermocosmetic treatment.

OBJECTIVES

To assess skin biophysical parameters in French and Brazilian subjects and to verify the efficacy of four dermocosmetic treatments in these populations.

METHODS

Five test areas were defined on each volar forearm of the eighteen Brazilian and eighteen French participants using a randomized design. Biophysical measurements in terms of skin hydration, skin barrier function, skin brightness, and skin viscoelasticity were performed before and after 60 minutes of treatment.

RESULTS

Skin biophysical differences between populations were found. French skin has been shown to be more hydrated regarding epidermal mechanic properties and stratum corneum water content and more radiant when compared with Brazilian skin. However, it showed more signs of cutaneous aging and fatigue effects on skin. The Brazilian skin showed better skin barrier function. In addition, the treatments were effective in both populations.

CONCLUSIONS

Despite the differences found in French and Brazilian skin, the proposed dermocosmetic treatments showed effective in both populations.

Measurement of transepidermal water loss, stratum corneum hydration and skin surface pH in occupational settings: A review

BACKGROUND

The skin provides a permeable barrier which may be impaired in occupational settings. Transepidermal water loss (TEWL), stratum corneum hydration (SCH) and skin surface pH (SSpH) have been used in occupational settings to predict early onset of occupational skin diseases, to measure the effectiveness of prevention strategies for occupational skin diseases, and to assess skin condition during exposure. The aim was to compare the findings, identify shortcomings in the methodology and data reporting and furthermore, to make recommendations for future studies.

MATERIALS AND METHODS

A literature study was conducted on studies published before December 2018 to provide a review on the measurement of TEWL, SCH and SSpH in occupational settings.

RESULTS

TEWL, SCH and SSpH were previously measured in a wide variety of industries. Results between studies were highly variable, due to different study designs and different anatomical positions measured. Not all of the measurement conditions were reported and variations in study objectives led to data being reported and interpreted differently for most studies.

CONCLUSION

Incomplete reporting of methodology hinders comparison of bioengineering measurements. No bioengineering method has been proven useful as a predictive tool for occupational skin diseases, however, it is useful in the acute assessment of skin condition. It is recommended that future studies on TEWL, SCH and SSpH adhere to guidelines for occupational settings as far as possible to enable comparison between studies.

Skin Hydration Level as a Predictor for Diabetic Wound Healing: A Retrospective Study

BACKGROUND

In the diabetic foot, the skin may crack and develop fissures, potentially increasing vulnerability to ulceration and infection. Therefore, maintaining adequate skin hydration may be crucial for diabetic wound healing. However, no clinical study has addressed this issue. This study aimed to determine and compare the effect of the skin hydration level on diabetic wound healing with that of the tissue oxygenation level, which is recognized as the most reliable parameter in predicting diabetic wound healing.

METHODS

This retrospective study included 263 diabetic patients with forefoot ulcers. Skin hydration and transcutaneous oxygen pressure data collected before and after percutaneous transluminal angioplasty were analyzed. Skin hydration and tissue oxygenation were graded as poor, moderate, or acceptable. Wound healing outcomes were graded as healed without amputation, minor amputation, or major amputation. Wound healing outcomes were compared using four parameters: skin hydration at baseline, transcutaneous oxygen pressure at baseline, post-percutaneous transluminal angioplasty skin hydration, and post-percutaneous transluminal angioplasty transcutaneous oxygen pressure.

RESULTS

Each of the four parameters exhibited statistically significant correlations with wound healing outcomes. In the concurrent analysis of both skin hydration and transcutaneous oxygen pressure, skin hydration was a dominant parameter (p = 0.0018) at baseline, whereas transcutaneous oxygen pressure was a dominant parameter (p < 0.0001) following percutaneous transluminal angioplasty.

CONCLUSIONS

Skin hydration level might be a useful predictor for diabetic wound healing. In particular, the skin hydration level before recanalization was found to be superior to transcutaneous oxygen pressure in predicting wound healing.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Risk, III.

In Vivo Determination of Moisturizers Efficacy on Human Skin Hydration by Confocal Raman Spectroscopy

This research work deals with in vivo testing of the efficacy of commercial moisturizer products on the hydration of human skin, as there are various in vitro and ex vivo studies questioning their activity. Confocal Raman spectroscopy was used for this purpose of assessing the efficacy of moisturizers on skin hydration mainly owing to its simple, non-invasive, non-destructive, timesaving, and cost-effective nature. Water content and natural moisturizing factor (NMF) of stratum corneum were analyzed and compared using this method at high wavenumber (2500-4000 cm^-1) and fingerprint (400-1800 cm^-1) spectral regions, respectively, as these two parameters are correlated to skin hydration. Four commercial moisturizer products of different brands were tested on volar forearm region of healthy human female volunteers. This study was conducted for a period of 30 days with 0, 7, and 30 days as time points of analysis. The results of this study clearly indicate that not all the moisturizer products hydrate the skin to the expected levels, and this extent of skin hydration varies with duration of application of these products.

The revised EEMCO guidance for the in vivo measurement of water in the skin

BACKGROUND

Noninvasive quantification of stratum corneum water content is widely used in skin research and topical product development.

METHODS

The original EEMCO guidelines on measurements of skin hydration by electrical methods and transepidermal water loss (TEWL) by evaporimeter published in 1997 and 2001 have been revisited and updated with the incorporation of recently available technologies.

RESULTS

Electrical methods and open-chamber evaporimeters for measurement of TEWL are still the preferred techniques to measure the water balance in the stratum corneum. The background technology and biophysics of these instruments remain relevant and valid. However, new methods that can image surface hydration and measure depth profiles of dermal water content now available. Open-chamber measurement of TEWL has been supplemented with semiopen and closed chamber probes, which are more robust to environmental influence and therefore convenient to use and more applicable to field studies. However, closed chamber methods interfere with the evaporation of water, and the methods cannot be used for continuous monitoring. Validation of methods with respect to intra- and inter-instrument variation remains challenging. No validation standard or test phantom is available.

RESULTS AND CONCLUSIONS

The established methods for measurement of epidermal water content and TEWL have been supplemented with important new technologies including methods that allow imaging of epidermal water distribution and water depth profiles. A much more complete and sophisticated characterization of the various aspects of the dermal water barrier has been accomplished by means of today's noninvasive techniques; however, instrument standardization and validation remain a challenge.

Influence of digestive enzymes on development of incontinence-associated dermatitis: Inner tissue damage and skin barrier impairment caused by lipidolytic enzymes and proteases in rat macerated skin

One of the most common complications in patients with incontinence is incontinence-associated dermatitis. This study aimed to examine the influences of lipidolytic enzymes and/or proteases on skin barrier and tissue structure on the development of incontinence-associated dermatitis. Two animal experiments, ex vivo and in vivo, were performed using rats to examine the influences of 3 factors (maceration, proteases, and lipidolytic enzymes) alone or in various combinations on the barrier function and histology of the skin. As a result, skin treatments, including both of the skin maceration and proteases application, caused erythrocyte leakage from the blood vessels in the dermis. The erythrocyte leakage was observed in a larger area in the skin treated with proteases and lipidolytic enzymes with maceration than in the skin treated with proteases with maceration, that is, the addition of lipidolytic enzymes to skin maceration with proteases enhanced erythrocyte leakage. Lipidolytic enzymes in macerated skin are factors that accelerate tissue damage via skin barrier impairment, and proteases are the factors that trigger the development of incontinence-associated dermatitis via tissue damage. Advanced nursing care of perineal skin in patients with faecal incontinence is required because of the deleterious influence of lipidolytic enzymes and proteases.

Frailty and body mass index are associated with biophysical properties of the skin in community-dwelling older adults

AIM OF THE STUDY

This study aimed to investigate the association of frailty and body mass index (BMI) with biophysical properties of the skin in community-dwelling older people.

MATERIALS AND METHODS

A cross-sectional study was conducted in a suburban Japanese city. Older adults aged ≥65 years and participating in a health checkup program were recruited (n = 128). Stratum corneum hydration, clinical manifestations of dry skin, skin elasticity and condition of the dermis (as measured by ultrasonography) were evaluated on the volar forearm. Frailty phenotype and BMI were also evaluated.

RESULTS

The mean age of participants was 74.5 years, and 96.1% were women. Skin thickness was significantly decreased in frail participants compared with non-frail participants in an age-adjusted multivariate model (p = 0.009). Frail participants showed significantly lower skin elasticity values than non-frail participants in a univariate analysis (p = 0.024), but this was not significant in the multivariate model. In participants with BMI ≥25 kg/m², clinical manifestations of dry skin were significantly decreased compared with BMI <21.5 kg/m² (p = 0.002). Participants with BMI ≥25 kg/m² and with 21.5 ≤ BMI <25 kg/m² showed significantly higher skin elasticity values than participants with BMI <21.5 kg/m² (p = 0.014 and p = 0.042, respectively).

CONCLUSION

Frailty was associated with decreased skin thickness and decreased skin elasticity partially via the influence of chronological aging. Low body mass was associated with increased xerosis manifestations and decreased skin elasticity in community-dwelling older adults.

Solvent-Extracted Wool Wax: Thermotropic Properties and Skin Efficacy

BACKGROUND/AIMS

Wool wax is a soft, yellow, waxy substance that is secreted by the sebaceous glands of sheep. The purpose of wool wax is to waterproof and protect the wool. Chemically, wool wax is a complex mixture of esters, fatty acids, and alcohols. Wool waxes with different prop-erties can be obtained by following different extraction methodologies.

METHODS

Two differently extracted wool waxes are compared in this study. Their effectiveness in mimicking the properties of skin lipids is evaluated. In addition, the lipid compositions and thermotropic behaviours of the 2 differently extracted wool waxes were evaluated.

RESULTS

The solvent-extracted wool wax was found to have a significantly higher polar lipid content than that of the water-extracted wool wax. This increase in the polar character of the solvent-extracted wool wax was also demonstrated by increased values of transition and degradation temperatures in the differential scanning calorimetry and thermogravimetric analyses, respectively. In addition, solvent-extracted wool wax demonstrated the ability to reinforce stratum corneum lipids, which led to improved skin barrier function.

CONCLUSIONS

The suitability of the solvent-extracted wool wax for application in the preparation of cosmetics and dermatological products was demonstrated.

Standardized extract of wild apple fruit in alkyl-polyglucoside-based cosmetic cream - estimation of stability, safety, antioxidant activity and efficiency

OBJECTIVE

The aim of this study was in vitro and in vivo characterization of cosmetic cream with 6% of wild apple fruit water extract, containing 3.5% of alpha-hydroxyacids-AHAs and polyphenolic compounds, stabilized by biodegradable alkyl-polyglucoside emulsifiers.

METHODS

In vitro characterization of cream included organoleptic and physico-chemical (pH values and electrical conductivity) analysis, antioxidant activity-AA estimation (using DPPH test) during 180 days of storage at 22±2°C and determination of cosmetic active substances content-AHAs (using HPLC analysis). In vivo estimation of skin irritation potential after creams application under occlusion during 24h was investigated employing the biophysical methods on 12 healthy volunteers; hydration efficiency, transepidermal water loss-TEWL, skin pH, erythema-EI and melanin index-MI on 10 healthy volunteers after 28 days of cream application and bleaching efficiency on 10 healthy volunteers after 7 days of cream application after artificially induced skin hyperpigmentation.

RESULTS

Investigated cosmetic cream was pale beige color, odorless, semi-solid consistency and homogeneous, with pH values of 6.53±0.14, electrical conductivity above 50 μS/cm and AA of 24.96%RSC after preparation and these characteristics were stable during investigated period. In vivo measurements revealed absence of skin irritation after cream application under occlusion, which was part of it's safety profile. Increase of skin hydration after 14 days of cream application was 17.28±12.23 and after 28 days 21.19±7.59. In addition, in performed experiment TEWL and skin pH values during cream application remained unchanged. Cream application after artificial hyperpigmentation induced decrease of MI (∆MI after 7 days was -45.30±18.55) CONCLUSION: Formulated cosmetic cream with 6% of standardized wild apple fruit water extract and stabilized by biodegradable alkyl-polyglucoside emulsifiers demonstrated good stability, acceptable level of in vitro antioxidant activity, absence of skin irritation after cream application under occlusion and positive effects of cream on human skin after application (hydrating and bleaching effects). All mentioned properties make the cream suitable for possible usage as cosmetic product for preventing the skin damages caused by oxidative stress, for moisturizing the dry skin and bleaching of skin hyperpigmentation. This article is protected by copyright. All rights reserved.

Specific barrier response profiles after experimentally induced skin irritation in vivo

Background

Recently, natural moisturizing factors (NMFs) and corneocyte surface topography were suggested as biomarkers for irritant dermatitis.

Objectives

To investigate how exposure to different irritants influences corneocyte surface topography, NMF levels and the barrier function of human skin in vivo.

Methods

Eight healthy adult volunteers were exposed to aqueous solutions of 60% n‐propanol, 0.5% sodium lauryl sulfate (SLS), 0.15% sodium hydroxide, and 2.0% acetic acid, and distilled water, in a repeated irritation test over a period of 96 hours. Erythema, transepidermal water loss (TEWL), skin hydration, the dermal texture index (DTI) and NMF levels were measured at baseline, and after 24 and 96 hours.

Results

SLS and sodium hydroxide had the most pronounced effects on erythema and TEWL. Although n‐propanol caused only slight changes in TEWL and erythema, it showed pronounced effects on skin hydration, NMF levels, and the DTI. NMF was the only parameter that was significantly altered by all investigated irritants. The changes in the DTI were inversely associated with NMF levels and skin hydration.

Conclusion

Skin barrier impairment and the inflammatory response are irritant‐specific, emphasizing the need for a multiparametric approach to the study of skin irritation. NMF levels seem to be the most sensitive parameter in detecting irritant‐induced skin barrier alterations.

Claimed Effects, Outcome Variables and Methods of Measurement for Health Claims Proposed Under European Community Regulation 1924/2006 in the Framework of Maintenance of Skin Function

Evidence suggests a protective role for several nutrients and foods in the maintenance of skin function. Nevertheless, all the requests for authorization to use health claims under Article 13(5) in the framework of maintenance of skin function presented to the European Food Safety Authority (EFSA) have received a negative opinion. Reasons for such failures are mainly due to an insufficient substantiation of the claimed effects, including the choice of inappropriate outcome variables (OVs) and methods of measurement (MMs). The present paper reports the results of an investigation aimed at collecting, collating and critically analyzing the information with relation to claimed effects (CEs), OVs and MMs related to skin health compliance with Regulation 1924/2006. CEs, OVs and MMs were collected from both the EFSA Guidance document and from the authorization requests of health claims under Article 13(5). The critical analysis of OVs and MMs was based on a literature review, and was aimed at defining their appropriateness (alone or in combination with others) in the context of a specific CE. The results highlight the importance of an adequate choice of OVs and MMs for an effective substantiation of the claims.

Alkyl polyglucoside vs. ethoxylated surfactant-based microemulsions as vehicles for two poorly water-soluble drugs: physicochemical characterization and in vivo skin performance

Two types of biocompatible surfactants were evaluated for their capability to formulate skin-friendly/non-irritant microemulsions as vehicles for two poorly water-soluble model drugs differing in properties and concentrations: alkyl polyglucosides (decyl glucoside and caprylyl/capryl glucoside) and ethoxylated surfactants (glycereth-7-caprylate/ caprate and polysorbate 80). Phase behavior, structural inversion and microemulsion solubilization potential for sertaconazole nitrate and adapalene were found to be highly dependent on the surfactants structure and HLB value. Performed characterization (polarized light microscopy, pH, electrical conductivity, rheological, FTIR and DSC measurements) indicated a formulation containing glycereth- 7-caprylate/caprate as suitable for incorporation of both drugs, whereas alkyl polyglucoside-based systems did not exhibit satisfying solubilization capacity for sertaconazole nitrate. Further, monitored parameters were strongly affected by sertaconazole nitrate incorporation, while they remained almost unchanged in adapalene-loaded vehicles. In addition, results of the in vivo skin performance study supported acceptable tolerability for all investigated formulations, suggesting selected microemulsions as promising carriers worth exploring further for effective skin delivery of model drugs.

Preparation of Keratin Hydrolysate from Chicken Feathers and Its Application in Cosmetics

Keratin hydrolysates (KHs) are established standard components in hair cosmetics. Understanding the moisturizing effects of KH is advantageous for skin-care cosmetics. The goals of the protocol are: (1) to process chicken feathers into KH by alkaline-enzymatic hydrolysis and purify it by dialysis, and (2) to test if adding KH into an ointment base (OB) increases hydration of the skin and improves skin barrier function by diminishing transepidermal water loss (TEWL). During alkaline-enzymatic hydrolysis feathers are first incubated at a higher temperature in an alkaline environment and then, under mild conditions, hydrolyzed with proteolytic enzyme. The solution of KH is dialyzed, vacuum dried, and milled to a fine powder. Cosmetic formulations comprising from oil in water emulsion (O/W) containing 2, 4, and 6 weight% of KH (based on the weight of the OB) are prepared. Testing the moisturizing properties of KH is carried out on 10 men and 10 women at time intervals of 1, 2, 3, 4, 24, and 48 h. Tested formulations are spread at degreased volar forearm sites. The skin hydration of stratum corneum (SC) is assessed by measuring capacitance of the skin, which is one of the most world-wide used and simple methods. TEWL is based on measuring the quantity of water transported per a defined area and period of time from the skin. Both methods are fully non-invasive. KH makes for an excellent occlusive; depending on the addition of KH into OB, it brings about a 30% reduction in TEWL after application. KH also functions as a humectant, as it binds water from the lower layers of the epidermis to the SC; at the optimum KH addition in the OB, up to 19% rise in hydration in men and 22% rise in women occurs.

Quantitation of 24-Hour Moisturization by Electrical Measurements of Skin Hydration

PURPOSE

The purpose of this study was to quantify the effects of several moisturizers on hydration of the stratum corneum by measuring their effect on electrical conductance over a 24-hour period.

DESIGN

Double-blind, randomized controlled trial.

SUBJECTS AND SETTING

Twenty-five healthy female volunteers aged 18 to 65 years with dry skin on the lower legs and no other known dermatologic pathology participated in the study. Additional exclusion criteria were pregnant or taking anti-inflammatory steroids. The study was carried out in a clinical research facility in Winnipeg, Manitoba, Canada.

METHODS

Subjects underwent a 3-day conditioning period using a natural soap bar on the lower legs and no application of moisturizer to the skin. Participants then came to the test site and equilibrated for at least 30 minutes under controlled conditions of temperature and humidity. After baseline hydration measurements on test sites on the lower legs of each subject, a single application of each of 5 test products at a dose of 2 mg/cm was made. Skin hydration was assessed by electrical conductance measurements with a specialized probe. The probe was briefly placed on the skin surface with light pressure, and the measurement recorded in units of microsiemens (μS). Conductance was measured at 2, 4, 6, 8, and 24 hours after product applications.

RESULTS

Although all but 1 of the test products increased conductance at 2 hours, only 2 moisturizers containing high levels of glycerin (products C and E) maintained increased conductance relative to baseline at 24 hours, +37.8 (P < .001) and +103.5 (P < .001), respectively.

CONCLUSIONS

Moisturizers containing high levels of glycerin can provide a measurable moisturization benefit as determined by skin conductance for at least 24 hours after a single application.

Comparative instrumental evaluation of efficacy and safety between a binary and a ternary system in chemexfoliation

OBJECTIVE

To instrumentally evaluate the efficacy and the safety of a new ternary system chemo exfoliating formulation (water-dimethyl isosorbide-acid) vs traditional binary systems (water and acid) where the acid is maintained in both the systems at the same concentration.

METHODS

Different peelings (binary system pyruvic acid and trichloroacetic acid-TCA, and ternary system pyruvic acid and TCA) were tested on the volar forearm of 20 volunteers of both sexes between 28 and 50 years old. The outcomes were evaluated at the baseline, 10 minutes, 24 hours, and 1 week after the peeling by means of noninvasive skin diagnosis techniques. In vivo reflectance confocal microscopy was used for stratum corneum evaluation, transepidermal waterloss, and Corneometry for skin barrier and hydration, Laser Doppler velocimetry in association with colorimetry for irritation and erythema analysis.

RESULTS

The instrumental data obtained showed that the efficacy and safety of the new ternary system peel compounds were significantly higher compared with the binary system formulations tested. The new formulation peels improved chemexfoliation and reduced complications such as irritation, redness, and postinflammatory pigmentation compared to the traditional aqueous solutions.

CONCLUSION

The study showed that ternary system chemexfoliation, using a controlled delivery technology, was able to provide the same clinical effects in term of stratum corneum reduction with a significantly reduced barrier alteration, water loss, and irritation/erythema compared to traditional binary system peels.

Human axillary skin condition is improved following incorporation of glycerol into the stratum corneum from an antiperspirant formulation

The study objectives were to demonstrate that glycerol, when topically applied from a roll-on antiperspirant formulation, can be delivered directly to human skin ex vivo and the axillary stratum corneum (SC) in vivo, and to assess whether it improves the quality of the axillary skin barrier. Ex vivo human skin absorption of glycerol was measured following application of a roll-on antiperspirant formulation containing 4% ¹³C₃-glycerol. Skin distribution of ¹³C₃-glycerol over 24 h was assessed using gas chromatography-mass spectrometry. In vivo axillary SC penetration was measured by confocal Raman spectroscopy and multivariate curve-resolution software 1 h after topical application of a roll-on antiperspirant formulation containing 8% deuterated glycerol (d₅-glycerol). A clinical study was conducted to determine the efficacy of a roll-on antiperspirant formulation containing 4% glycerol in reducing shaving-induced visual irritation and in increasing axillary-skin hydration. Ex vivo skin absorption studies indicated that the formulation delivered ¹³C₃-glycerol into the SC at all timepoints over the 24-h period. In vivo Raman measurements (1 h after application) demonstrated that d₅-glycerol was detectable to a depth of at least 10 μm in the axillary SC. Application of 4% glycerol from a roll-on antiperspirant formulation to the axilla was associated with significantly less visible irritation and greater skin hydration than observed with the control (glycerol-free) product. These studies demonstrate that glycerol, incorporated in a roll-on antiperspirant formulation, is delivered directly and rapidly to all depths of the axillary SC, and results in improvements in visible irritation and hydration in the axilla.

Application of three hygrometers under different skin conditions in dogs: dry, moist and haired skin

BACKGROUND

Hydration is one parameter of skin barrier function. The Skicon-200EX^® and Corneometer CM825^® are hygrometers used to measure skin hydration in humans based on different measurement methods. The ASA-MX3^® is a hygrometer used to obtain measurements at haired skin sites in humans.

HYPOTHESIS/OBJECTIVES

To validate three hygrometers to measure skin dryness in dogs.

ANIMALS

Six clinically normal research dogs.

METHODS

In vivo evaluation of three hygrometers for three different skin types was performed. Measurement of hydration was performed at five different regional sites. Dry and moist skin were induced by treatment with a sorbent and petrolatum, respectively, and measurements were collected for 120 min. Skin sites with three different hair lengths were evaluated to determine whether hair would interfere with hydration measurements.

RESULTS

All three hygrometers obtained measurements at the nonhaired skin sites, except the ASA-MX3^® hygrometer at the ear site. At the dry skin sites the Skicon-200EX^® hygrometer detected a significant decrease of water content for longer than the other devices. At the moist skin sites the Corneometer CM825^® and ASA-MX3^® hygrometers showed a significant increase in water content. The ASA-MX3^® hygrometer was the only device that could obtain measurements at sites with hair.

CONCLUSIONS AND CLINICAL IMPORTANCE

The Skicon-200EX^® hygrometer was the most sensitive for detecting skin dryness, whereas the Corneometer CM825^® and ASA-MX3^® hygrometers detected an emollient effect. Only the ASA-MX3^® could provide measurements at the haired sites. This study may assist in the selection of a hygrometer based on the purpose of use.

Skin hydration and lifestyle-related factors in community-dwelling older people

OBJECTIVE

This study aimed to investigate skin hydration status of the lower legs by comparing several methods and examining lifestyle-related factors in community-dwelling older people.

METHODS

A cross-sectional study was conducted in three community settings in Japan from autumn to winter. Participants were older people aged ≥65 years (n=118). Skin hydration status of the lower legs was evaluated by stratum corneum hydration using an electrical device, clinical symptoms by an expert's observation and the visual analogue scale. Lifestyle factors of skin care were evaluated by a self-administered questionnaire.

RESULTS

The mean age of participants was 74.4 years and 83.9% were women. Stratum corneum hydration was significantly correlated with clinical scores by an expert's observation (rho=-0.46, P<0.001), but it was not correlated with the visual analogue scale (rho=-0.08, P=0.435). Among participants who did not perceive dry skin, 57.5% showed low stratum corneum hydration. Hospitalization in the past year (b=-9.4, P=0.008), excessive bathing habits (b=-4.6, P=0.014), and having an outdoor hobby (b=-5.7, P=0.007) were negatively associated, and diuretics (b=11.5, P=0.002) and lotion-type moisturizer use (b=4.6, P=0.022) were positively associated with stratum corneum hydration.

CONCLUSION

Stratum corneum hydration measurements show an adequate association with observation-based evaluation by an expert, but poor agreement with subjective evaluation in community-dwelling older people. Hospitalization experience and lifestyle factors are associated with skin hydration.

Role of mast cells in the induction of dry skin in a mouse model of rheumatoid arthritis

PURPOSE

Rheumatoid arthritis (RA) is known to induce dry skin as an extra-articular symptom. However, the mechanisms behind the induction are unclear. In this study, we utilized an arthritis mouse model to simulate RA to reveal the relationship between arthritis and dry skin.

MATERIALS AND METHODS

DBA/1JJmsSlc control mice (n = 5) and DBA/1JJmsSlc collagen-induced arthritis mouse model (arthritis mice; n = 5) were used. We measured transepidermal water loss (TEWL) and capacitance to reveal the effect of arthritis on skin barrier function. In addition, we measured the expression of biomarkers of skin barrier function.

RESULTS

We found that the hind limb volume of the arthritis mice was higher than that of the control mice. Our results showed that the arthritis mice had higher TEWL and lower capacitance when compared to the control mice. When compared to that of the control mice, the skin of the arthritis mice was thicker with more leukocyte infiltration. In the skin of arthritis mice, we observed lower expression of type I and IV collagens, but higher expression of matrix metalloproteinases (MMP)-1 and -9 when compared to that of the control mice. The levels of mast cells, histamine, substance P, and tryptase were higher in the arthritis mice than in the control mice. This study showed that the arthritis mice exhibited a disruption of skin barrier function (i.e. dry skin), which was improved following treatment with a mast cell inhibitor.

CONCLUSIONS

Our results on mast cells suggested that an improvement of dry skin is important for RA management.

The estimation of the traditionally used yarrow (Achillea millefolium L. Asteraceae) oil extracts with anti-inflamatory potential in topical application

ETHNOPHARMACOLOGICAL RELEVANCE

Olive or sunflower oil yarrow extracts have been extensively used against inflammatory disorders and skin wound healing in traditional medicine.

AIM OF THE STUDY

To evaluate oil yarrow extracts traditional use in treatment of topical/dermatological skin impairments, sodium lauryl sulfate test was applied, and in vivo measuring of the biophysical parameters (erythema index, skin capacitance and the pH of the skin) in the artificially irritated skin was performed. As traditionally olive and sunflower oil have been used equally for extracts production, the experiment was carried out to investigate whether any of the oil extractants has the advantage over the other, and if the method of extraction might influence the desired activity. The observed activity has been connected to the chemical profile of the investigated extracts and their antioxidative properties.

MATERIALS AND METHODS

In vivo measurements were performed using the appropriate probes for measuring skin capacitance, pH of the skin and erythema index (EI). The designed experiment enabled the evaluation of the anti-inflammatory effects of a seven-day application of oil yarrow extracts known in traditional medicine, on artificially irritated skin of volunteers. The chemical profile for the investigated samples was achieved applying the HPLC and UHPLC-MS methods. Also, ferric reducing antioxidant power (FRAP) test was performed to assess the antioxidant properties of the investigated samples.

RESULTS

The application of tested oil extracts on artificially irritated skin in vivo demonstrated the ability to re-establish their optimal pH and hydration of skin to the values measured prior to the irritation. Considering the EI transition, the investigated samples succeeded in re-establishing the baseline values, with no significant difference after three- and seven-day application.

CONCLUSIONS

The data obtained in the study showed that the oil yarrow extracts had an evident anti-inflammatory property. Namely, the investigated extracts demonstrated significant anti-inflammatory effect in an in vivo double blind randomized study, using a sodium lauryl sulfate test. The skin parameters assessed in the study (skin capacitance, pH and EI) were restored to the basal values after three- and seven-day treatment with the tested extracts. The shown effects were attributed to yarrow oil extracts composition. The yarrow oil extracts might be used as promising base in the phytopreparations designed for dermatological application as anti-inflammatory agents with a positive impact on the skin pH and its moisture content.

A comparison of the effect of certain inorganic salts on suppression acute skin irritation by human biometric assay: A randomized, double-blind clinical trial

Background:

Strontium, zinc, and potassium salts have been demonstrated to inhibit irritation and inflammation when applied topically. Particularly, strontium chloride (SC) and potassium nitrate (KN) are reported to reduce skin and tooth sensitivity. The aim of the present study was to compare the anti-irritant effects of four inorganic salts and assign the ingredient which can suppress skin irritation due to chemical or environmental exposure, more effectively. We compared the anti-inflammatory effects of SC, strontium nitrate (SN), KN, and zinc chloride (ZC).

Materials and Methods:

This double-blind trial was conducted on 32 healthy volunteers with sensitive skin. Irritation was induced by 24 h exposure with 1.0% sodium lauryl sulfate on arms. Treatments were applied by an ointment of SN, SC hexahydrate, KN, and ZC and their 1%, 3%, and 5% (w/v) concentrations were prepared. The dosage was twice daily for 6 days to the irritated areas. Skin reactions were evaluated instrumentally.

Results:

SC had a beneficial effect that was significant overall. All other treatments exert a protective effect in skin barrier function but not significantly. With the exception of ZC, all test substances improved skin hydration but the effect of SC was significant. In respect of colorimetric assessment, all treatments, excluding ZC, reduced erythema significantly compared with an untreated control 7 days after treatment start. There was no support for a dose-response effect.

Conclusion:

Analysis of the biometric measurements revealed that the strontium salts are best, not treating is worst, and there is little difference between the other treatments. Hence, the skin care products containing SC and SN may reduce the signs and symptoms of irritant contact dermatitis.

A Wearable Hydration Sensor with Conformal Nanowire Electrodes

A wearable skin hydration sensor in the form of a capacitor is demonstrated based on skin impedance measurement. The capacitor consists of two interdigitated or parallel electrodes that are made of silver nanowires (AgNWs) in a polydimethylsiloxane (PDMS) matrix. The flexible and stretchable nature of the AgNW/PDMS electrode allows conformal contact to the skin. The hydration sensor is insensitive to the external humidity change and is calibrated against a commercial skin hydration system on an artificial skin over a wide hydration range. The hydration sensor is packaged into a flexible wristband, together with a network analyzer chip, a button cell battery, and an ultralow power microprocessor with Bluetooth. In addition, a chest patch consisting of a strain sensor, three electrocardiography electrodes, and a skin hydration sensor is developed for multimodal sensing. The wearable wristband and chest patch may be used for low-cost, wireless, and continuous monitoring of skin hydration and other health parameters.

Emerging Technology for Enhanced Assessment of Skin Status

Pressure injury (PI) prevention has become a key nursing priority that requires clear identification of visual cues representative of PI risk. There is generalized agreement that erythema and skin wetness and/or maceration should be routinely examined by the clinician as part of PI risk assessment. Such an assessment is largely qualitative, deeply reliant on the perception and interpretation of the clinician. Consequently, skin parameters may be misinterpreted, underestimated, or even missed completely. Objective techniques are needed to augment accurate assessment of erythema and skin wetness and/or maceration. Biophysical skin analysis devices have been widely used in the cosmetic industry and clinical research to measure certain skin parameters for the purpose of skin health evaluation. This article describes 3 devices that enable noninvasive digital measurements of epidermal hydration, erythema, and epidermal lipids, respectively. The clinical application of biophysical skin analysis instruments in the assessment PI-related skin parameters could provide a feasible alternative to subjective assessment.

Genetic and Environmental Influences on General Skin Traits: Healthy Twins and Families in Korea

Family study can provide estimates of overall genetic influences on a particular trait because family relationships provide accurate measures of average genetic sharing. However, evidence of genetic contributions to skin phenotypes is limited, which may preclude genetic studies to identify genetic variants or to understand underlying molecular biology of skin traits. This study aimed to estimate genetic and environmental contributions to selected dermatologic phenotypes, that is, to melanin index, sebum secretion, and skin humidity level in a Korean twin-family cohort. We investigated more than 2,000 individuals from 486 families, including 388 monozygotic twin pairs and 82 dizygotic twin pairs. Variance component method was used to estimate genetic influences in terms of heritability. Heritability of skin melanin index, sebum secretion, and skin humidity (arm and cheek) were estimated to be 0.44 [95% CI 0.38-0.49], 0.21 [95% CI 0.16-0.26], 0.13 [95% CI 0.07-0.18], and 0.11 [95% CI 0.06-0.16] respectively, after adjusting for confounding factors. Our findings suggest that genetics play a major role on skin melanin index, but only mild roles on sebum secretion and humidity. Sebum secretion and skin humidity are controlled predominantly by environmental factors notably on shared environments among family members. We expect that our findings add insight to determinants of common dermatologic traits, and serve as a reference for biologic studies.