Changes in skin barrier function following long-term treatment with moisturizers, a randomized controlled trial

Short-term skin reactions and changes in stratum corneum following different ways of facial sheet mask usage

BACKGROUND

The global facial mask market grows steadily at 8.5 % annually. However, prolonged use may lead to skin inflammation.

OBJECTIVE

To investigate how various mask types and wearing durations impact skin physiology and aquaporins3 (AQP3) expression in healthy subjects.

METHODS

We used a randomized controlled design to investigate the effects of three types of facial masks (pure water, hyaluronan, and bifida ferment lysate) and four different duration(5, 15, 25, and 40 min) on various skin parameters in volunteers, assessing moisture content, transepidermal water loss (TEWL), sebum, corneocyte size, and AQP3 expression before and after mask application, while also evaluating adverse reactions, discomfort, and noncompliance.

RESULT

Hydration and TEWL increased at first, then decreased. Sebum increased with all types of masks, particularly after 40 min. Vasodilation and AQP3 expression were linked to mask duration. Corneocyte sizes remained constant. The main adverse reactions were redness (10.71 %, n = 28) and dryness (57.14 %, n = 28), especially with pure water masks lasting over 25 min.

CONCLUSION

Short-term use of facial sheet masks (<25 min) benefits skin with improved hydration, reduced redness, and AQP3 activation, while prolonged use can lead to increased dryness and redness.

Potential Role of the Skin in Hypertension Risk Through Water Conservation

Previous basic and clinical investigations have identified various pathogenic factors and determinants of risk that contribute to hypertension. Nevertheless, the pathogenesis of hypertension has not been fully elucidated. Moreover, despite the availability of antihypertensive medications for the management of blood pressure, treatments that address the full spectrum of the pathophysiological defects underpinning hypertension remain to be identified. To further investigate the mechanisms of primary hypertension, it is imperative to consider novel potential aspects, such as fluid management by the skin, in addition to the conventional risk factors. There is a close association between body fluid regulation and blood pressure, and the kidney, which, as the principal organ responsible for body fluid homeostasis, is the primary target for research in the field of hypertension. In addition, the skin functions as a biological barrier, potentially contributing to body fluid regulation. In this review, we propose the hypothesis that changes in skin water conservation are associated with hypertension risk based on recent findings. Further studies are required to clarify whether this novel hypothesis is limited to specific hypertension or applies to physiological blood pressure regulation.

Role of basal sweating in maintaining skin hydration in the finger: A long-standing paradox in dry skin resolved

A long-standing paradox in dermatology is why skin dehydration in the fingers can be triggered by repeated water exposure despite the action of water to hydrate skin tissue. Potential clues might be provided by identifying a mechanism through which water is held in the skin of the fingers. We speculated that this mechanism would be impaired after repeated water exposure. Here, we investigated whether there might be glabrous skin-specific water-holding machinery and whether this machinery might be impaired in dry skin/hand eczema. We examined this by using an impression-mould technique, allowing for an accurate quantification of sweat gland/duct activity and optical coherence tomography. Unlike in hairy skin, sweat pores were rarely detected at the folds of the finger at baseline. Surprisingly, after water exposure, sweat pores at the folds opened and those at the ridges closed in healthy controls (HCs). Sweating in the dermal folds of the hands correlated with skin hydration, and decreased in dry skin/hand eczema, suggesting that its impairment may be one of the causes of dry skin. After repeated water exposure, basal sweating response at the folds was exhausted in patients with dry skin/hand eczema as well as HCs. This exhaustion was rescued by exposing individuals to high humidity. Basal sweating defects would be a target for dry skin/hand eczema. Maintaining basal sweating responses in the finger is the best preventive measures in achieving prevention of dry skin/hand eczema.

Proline, hydroxyproline, and pyrrolidone carboxylic acid derivatives as highly efficient but reversible transdermal permeation enhancers

Overcoming the skin barrier properties efficiently, temporarily, and safely for successful transdermal drug delivery remains a challenge. We synthesized three series of potential skin permeation enhancers derived from natural amino acid derivatives proline, 4-hydroxyproline, and pyrrolidone carboxylic acid, which is a component of natural moisturizing factor. Permeation studies using in vitro human skin identified dodecyl prolinates with N-acetyl, propionyl, and butyryl chains (Pro2, Pro3, and Pro4, respectively) as potent enhancers for model drugs theophylline and diclofenac. The proline derivatives were generally more active than 4-hydroxyprolines and pyrrolidone carboxylic acid derivatives. Pro2-4 had acceptable in vitro toxicities on 3T3 fibroblast and HaCaT cell lines with IC₅₀ values in tens of µM. Infrared spectroscopy using the human stratum corneum revealed that these enhancers preferentially interacted with the skin barrier lipids and decreased the overall chain order without causing lipid extraction, while their effects on the stratum corneum protein structures were negligible. The impacts of Pro3 and Pro4 on an in vitro transepidermal water loss and skin electrical impedance were fully reversible. Thus, proline derivatives Pro3 and Pro4 have an advantageous combination of high enhancing potency, low cellular toxicity, and reversible action, which is important for their potential in vivo use as the skin barrier would quickly recover after the drug/enhancer administration is terminated.

Effectiveness of Dietary Supplement for Skin Moisturizing in Healthy Adults: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Background

The dietary supplement industry offers many oral cosmetics that purportedly assist in skin moisturization often with unclear evidence supporting efficacy and safety. To update the accessible proofs pertaining to the safety and effectiveness of oral dietary supplements to facilitate skin moisturizing via an all-around review and meta-analysis.

Methods

Three on-line databases [Pubmed, Embase, and Cochrane Library (CENTRAL)] were retrieved from January 2000 to November 2021. An overall 66 randomized controlled trials (RCTs) of skin care were recognized. Meta-analysis was performed for dietary supplements with four or more available research.

Results

Oral collagen or ceramide resulted in a statistically significant increase in skin hydration and a decrease in transepidermal water loss (TEWL) compared to placebo. No benefits regarding the improvement of skin conditions in terms of water content and TEWL were observed for lactic acid bacteria or Lactobacillus fermented foods. A statistically significant and positive effect on skin hydration was observed for both hyaluronan and procyanidin, with an unknown effect on TEWL due to insufficient RCTs. There was a non-significant improvement in the water content of stratum corneum for astaxanthin based on subgroup analyses. Among the dietary supplements trialed in ≤ 3 RCTs, the judgment regarding their effects on skin moisturizing was prevented by inconsistent conclusions as well as insufficient research. All food supplements were safe throughout the research (normally ≤ 24 weeks).

Conclusion

Oral dietary supplements, including collagen, ceramides, hyaluronan, and procyanidin, were proven to be effective for skin moisturization. At present, for skin moisturization, the proofs supporting the recommendation of other dietary supplements, such as lactic acid bacteria and astaxanthin, are insufficient.

Systematic Review Registration

http://www.crd.york.ac.uk/PROSPERO/ identifier CRD42021290818.

A consistent skin care regimen leads to objective and subjective improvements in dry human skin: investigator-blinded randomized clinical trial

BACKGROUND

Dry, itchy skin can lower quality of life (QoL) and aggravate skin diseases. Moisturizing skin care products can have beneficial effects on dry skin. However, the role of a daily skin care routine is understudied.

OBJECTIVE

To understand how daily skin care with a mild cleanser and moisturizer impacts skin health and patients' QoL, in dry skin population.

METHODS

A randomized, investigator-blinded study of 52 participants with moderate to severe dry skin. The treatment group (n = 39) used mild cleanser and moisturizer twice daily for two weeks whereas the control group (n = 13) used mild cleanser without moisturizer. Total Clinical Score (TCS; erythema, scale and fissures), Visual Dryness Score (VDS) and subjective itch-related quality of life (ItchyQoL) were collected.

RESULTS

The treatment group showed significantly more improvement in TCS and VDS compared to the control group after two weeks. Among the three components of the ItchyQoL (symptoms, functioning, and emotions), symptom showed significantly greater improvement in the treatment compared to the control group. Over 80% of participants in the treatment group agreed that the regimen led to decrease in dryness/pruritus and improved skin texture.

CONCLUSIONS

A consistent skin care regimen should be an integral component of management of dry skin.

In Vitro Modeling of Skin Barrier Disruption and its Recovery by Ceramide-Based Formulations

Disrupted skin barrier, one of the severe attributes of inflammatory skin diseases, is caused by lower content and pathological changes of lipids in the uppermost skin layer-stratum corneum (SC). Restoring skin barrier with native skin lipids, especially ceramides (Cers), appears to be a promising therapy with minimum side effects. For testing the efficiency of these formulations, suitable in vitro models of the skin with disrupted barriers are needed. For the similarity with the human tissue, our models were based on the pig ear skin. Three different ways of skin barrier disruption were tested and compared: tape stripping, lipid extraction with organic solvents, and barrier disruption by sodium lauryl sulfate. The level of barrier disruption was investigated by permeation studies, and parameters of each method were modified to reach significant changes between the non-disrupted skin and our model. Fourier transform infrared (FTIR) spectroscopy was employed to elucidate the changes of the skin permeability on the molecular scale. Further, the potential of the developed models to be restored by skin barrier repairing agents was evaluated by the same techniques. We observed a significant decrease in permeation characteristics through our in vitro models treated with the lipid mixtures compared to the untreated damaged skin, which implied that the skin barrier was substantially restored. Taken together, the results suggest that our in vitro models are suitable for the screening of potential barrier repairing agents.

In vivo examination of healthy human skin after short-time treatment with moisturizers using confocal Raman spectroscopy and optical coherence tomography: Preliminary observations

Skin is our barrier against environmental damage. Moisturizers are widely used to increase hydration and barrier integrity of the skin; however, there are contrasting observations on their in vivo effects in real-life settings. In cosmetic studies, corneometers and tewameters are traditionally used to assess skin hydration. In this study, two novel noninvasive diagnostic techniques, optical coherence tomography (OCT) and confocal Raman spectroscopy, were used to analyze stratum corneum and epidermal thickness (ET), water content, blood flow in function of depth, skin roughness, attenuation coefficient, natural moisturizing factor, ceramides and free fatty acids, cholesterol, urea, and lactates in 20 female subjects aged between 30 and 45 before and after 2 weeks application of a commercially available moisturizing lotion on one forearm. The untreated forearm served as control. A third measurement was conducted 1 week after cessation of moisturizing to verify whether the changes in the analyzed parameters persisted. We noticed a reduction in skin roughness, an increase in ceramides and free fatty acids and a not statistically significant increase in ET. As a conclusion, short time moisturizing appears insufficient to provide significant changes in skin morphology and composition, as assessed by OCT and RS. Novel noninvasive imaging methods are suitable for the evaluation of skin response to topical moisturizers. Further studies on larger sample size and longer treatment schedules are needed to analyze changes under treatment with moisturizers and to standardize the use of novel noninvasive diagnostic techniques.

Towards Optimal pH of the Skin and Topical Formulations: From the Current State of the Art to Tailored Products

Acidic pH of the skin surface has been recognized as a regulating factor for the maintenance of the stratum corneum homeostasis and barrier permeability. The most important functions of acidic pH seem to be related to the keratinocyte differentiation process, the formation and function of epidermal lipids and the corneocyte lipid envelope, the maintenance of the skin microbiome and, consequently, skin disturbances and diseases. As acknowledged extrinsic factors that affect skin pH, topically applied products could contribute to skin health maintenance via skin pH value control. The obtained knowledge on skins’ pH could be used in the formulation of more effective topical products, which would add to the development of the so-called products ‘for skin health maintenance’. There is a high level of agreement that topical products should be acidified and possess pH in the range of 4 to 6. However, formulators, dermatologists and consumers would benefit from some more precise guidance concerning favorable products pH values and the selection of cosmetic ingredients which could be responsible for acidification, together with a more extensive understanding of the mechanisms underlaying the process of skin acidification by topical products.

Aestivation motifs explain hypertension and muscle mass loss in mice with psoriatic skin barrier defect

AIM

Recent evidence suggests that arterial hypertension could be alternatively explained as a physiological adaptation response to water shortage, termed aestivation, which relies on complex multi-organ metabolic adjustments to prevent dehydration. Here, we tested the hypothesis that chronic water loss across diseased skin leads to similar adaptive water conservation responses as observed in experimental renal failure or high salt diet.

METHODS

We studied mice with keratinocyte-specific overexpression of IL-17A which develop severe psoriasis-like skin disease. We measured transepidermal water loss and solute and water excretion in the urine. We quantified glomerular filtration rate (GFR) by intravital microscopy, and energy and nitrogen pathways by metabolomics. We measured skin blood flow and transepidermal water loss (TEWL) in conjunction with renal resistive indices and arterial blood pressure.

RESULTS

Psoriatic animals lost large amounts of water across their defective cutaneous epithelial barrier. Metabolic adaptive water conservation included mobilization of nitrogen and energy from muscle to increase organic osmolyte production, solute-driven maximal anti-diuresis at normal GFR, increased metanephrine and angiotensin 2 levels, and cutaneous vasoconstriction to limit TEWL. Heat exposure led to cutaneous vasodilation and blood pressure normalization without parallel changes in renal resistive index, albeit at the expense of further increased TEWL.

CONCLUSION

Severe cutaneous water loss predisposes psoriatic mice to lethal dehydration. In response to this dehydration stress, the mice activate aestivation-like water conservation motifs to maintain their body hydration status. The circulatory water conservation response explains their arterial hypertension. The nitrogen-dependency of the metabolic water conservation response explains their catabolic muscle wasting.

Facial Skin Biophysical Profile of Women in Malaysia: Significance of Facial Skincare Product Use

INTRODUCTION

At present, there is a lack of baseline data on the facial skin biophysical profile of women in Malaysia. The implications related to the daily habits and facial skincare product use on the skin biophysical condition are, thus, unknown. In this study, we aim to evaluate facial skin biophysical parameters of Malaysian women and examine the influence of demographic characteristics, daily habits, and facial skincare product use on these parameters.

METHODS

Four skin biophysical parameters - transepidermal water loss (TEWL), melanin content, elasticity, and collagen intensity - were assessed on the cheek of the subjects (20-60 years). Demographic background, daily habits, and skincare product use were gauged through a survey. Only 197 from the 213 subjects recruited initially were used for analysis after the data were screened for normality.

RESULTS

The biophysical parameters were similar in different races, except a higher melanin content in Indian female individuals. Elasticity and collagen intensity reduced with age, while melanin content increased in the older age-groups. But no difference was observed in TEWL at different ages. Evaluating the influence of daily habits, we observed that exercise significantly lowered TEWL and increased melanin content, which may be associated with UV radiation exposure. Facial skincare products are popular among the female subjects (>85% users). Products with moisturizing, sunscreening, and other skincare functions (astringent, antiaging, and anti-wrinkle) were preferred by subjects of all ages. These product functions significantly improve skin elasticity and reduce melanin content in the young adults. While aged women recognized the importance of having an additional skin-lightening function in their skincare routine. Although the influence of individual skincare function on skin biophysical parameters was mostly positive, the alteration of these parameters varied at different ages.

CONCLUSION

This is the first report of facial skin biophysical profile of Malaysian women. There is no difference among 3 major races saved for melanin content. This work demonstrated age-dependent influences on the biophysical parameters, except TEWL. The significance of skincare product use is well reflected in the improvement of these parameters at different age-groups based on individual skincare functions.

Multi parametric biophysical assessment of treatment effects on xerotic skin

Background

Topical moisturizing products are widely used to alleviate the problems associated with xerotic skin. Their use affects many properties of the stratum corneum (SC) in a complex and interrelated manner. The range of measurement techniques available to the researcher has increased in recent years. However, few studies have looked for correlations between the different techniques for assessing how aspects of xerotic skin change over time as a result of topical moisturizer usage.

Objectives

A 3‐week in vivo study using an oil‐in‐water based moisturizing product and an untreated site was conducted to determine the clinical significance of and any correlations between a range of different approaches for the measurement of skin lipid content and also skin hydration and visual grading of dry skin.

Methods

A range of traditional and more recently developed skin measurement techniques have been used to examine a variety of SC properties in normal and xerotic skin during topical moisturizer usage.

Results

In vivo confocal Raman spectroscopy and analysis of SC lipids from tape strips both showed an increase in SC lipid level and organization after 3 weeks of moisturizer usage on xerotic skin. Hydration, measured both optically and electrically, also increased and skin barrier function improved, with strong correlations between the different measures of dryness being observed.

Conclusions

Strong correlations were observed between the skin measurements for lipid assessment and skin hydration with regard to the assessment of xerotic skin, providing valuable new information for future in vivo clinical research into dry and atopic skin.

Keywords

biophysical assessment, skin barrier, skin hydration, topical moisturizers, Xerosis

Raman spectroscopic analysis of skin penetration and moisturizing effects of Bionics vernix caseosa cream compared with Vaseline

BACKGROUND:

The stratum corneum (SC) is the outermost layer of human skin and deemed as barrier against chemical exposure and water loss. Moisturizers have beneficial effects in treating dry skin, especially the SC. Confocal Raman spectroscopy (CRS) was used to evaluate the efficacy of moisturizers on skin hydration and penetration, with such agents posing inherent characteristics of being noninvasive, nondestructive, timesaving, and cost effective. Bionics vernix caseosa (BVC) cream mimics the composition of vernix caseosa (VC), which could protect the newborn skin.

METHODS:

This research applied CRS to evaluate the penetration depth and water content variation during the intervention with two moisturizers, BVC cream and Vaseline. Volunteers received the 2 h application of BVC cream and Vaseline on the forearms. The evaluations on 0 h, 2 h, 4 h and 6 h were performed clinical assessment. Experimental data was processed by least square method and analysis of variance (ANOVA).

RESULTS:

The penetration depth of Vaseline was deeper than that of Bionics vernix caseosa cream. Specifically, BVC cream penetrated 18 μm into human skin, while Vaseline penetrated at least 20 μm. Compared with Vaseline, only BVC cream increased skin hydration, with a moisturizing effect lasting for 4 h. At 6 h, the Vaseline moisturizing effect decreased significantly.

Effects of skin moisturizer on the skin barrier dysfunction model: An evaluation of the heel via tape-stripping in healthy, young adults

BACKGROUND

This study seeks to establish the skin barrier dysfunction model at the heel via tape-stripping (TS) by evaluating the skin moisturizing effects.

MATERIALS AND METHODS

Nineteen young, female participated in the study. A sequence of TS was performed at the heel and trans-epidermal water loss (TEWL), stratum corneum (SC) hydration, and surface pH were measured. Following TS, the subjects were divided into three groups: moisturizer, emollient, and overcoat. These agents were applied daily at night, and the skin parameters were measured the next morning for a week.

RESULTS

The TEWL value of TS immediately and 5 min after TS were significantly higher than what was obtained before TS, while the SC hydration after TS was significantly lower than what was obtained before TS. However, there were no significant differences in the skin parameters among the three agents on day 7 after application, with the two-way ANOVA showing no interaction among the agents and number of days.

CONCLUSION

The skin barrier dysfunction model at the heel was established by TS in healthy, young adults. However, the physiological function of the skin at the heel did not change drastically and showed no differences even after continuous application for 7 days.

History of urea as a dermatological agent in clinical practice

Urea, also known as carbamide, is a polar, hygroscopic molecule produced by the human body that was first discovered in urine in 1773 by the French chemist Hilaire Rouelle and was artificially synthesised from inorganic precursors in 1828 by the German chemist Friedrich Wöhler. The importance of urea in dermatology is twofold: it primarily has a physiological key role for the maintenance of skin hydration, and it secondarily has been used for more than a century in different topical preparation and concentration in various skin conditions. One of the first uses of urea was the topical treatment of wounds because of its antibacterial and proteolytic properties. Since the second part of the 20th century, urea became one of the most common moisturisers and keratolytic agents, useful for the treatment of xerosis, atopic dermatitis, ichthyosis and psoriasis.

Skin Recovery After Discontinuation of Long-Term Moisturizer Application: A Split-Face Comparison Pilot Study

Introduction

Facial moisturizers are commonly used by healthy women and increasingly men of all age groups. This study aimed to investigate the effects of moisturizer discontinuation and the subsequent evolution of symptoms.

Methods

Two prospective observational split-face comparison pilot studies were performed in Switzerland and enrolled (I) 20 healthy women aged 17–25 years in winter and (II) 36 female subjects 15–20 and 40–55 years of age in summer. Moisturizers were stopped on the investigational half of the face. On the control side, the usual skin care regimen was continued. Daily subjective (I/II) and objective (I) skin assessments for the occurrence of typical symptoms of dry skin (dryness, itching, scales, redness, wrinkles) were collected.

Results

In the winter study (cohort I) in both the subjective and objective assessment, all skin changes increased significantly within 1 day after discontinuation. On day 7, dryness (p < 0.001), itching (p < 0.025), redness (p < 0.001) and scales (p < 0.049) were significantly different in the subjective assessment and redness (p < 0.004) and scales (p < 0.001) in the objective assessment. Skin dryness reverted to baseline levels after 6 days in the objective assessment and 10 days in the subjective assessment. The control side’s condition was reached after 6 days. In the summer study (II), only among the 15–20-year-olds was dryness significantly higher on the intervention side from day 1 (p < 0.028) to day 14 (p < 0.009). Their recovery time was 11 days until dryness intensity scores comparable to baseline were reached, and 21 days until the control side’s values were matched. Over a 7-day period, the overall mean dryness score was significantly different between the interventional and control sides for both young and old participants.

Conclusions

Both healthy young and aging female subjects react with typical symptoms of temporary dryness to a sudden stop of a previous long-term moisturizer treatment but regain normal levels quickly without continuation of moisturizers. The skin recovery time for skin dehydration is 1–3 weeks in young female subjects with varying intensities depending on the season.

Electronic supplementary material

The online version of this article (10.1007/s13555-020-00453-0) contains supplementary material, which is available to authorized users.

Effect of emulsifiers on drying stress and intercellular cohesion in human stratum corneum

OBJECTIVES

Emulsifier molecules, with their amphiphilic character, are ubiquitous in moisturizing creams and primarily serve to disperse the water-insoluble molecules such as emollients, oils, lipids and fats in water. The objective of this study was to investigate the effect of emulsifier molecules on the barrier and biomechanical properties of human stratum corneum (SC) and to compare the efficacy of emulsifier molecules when used in a fully formulated moisturizing cream.

METHODS

We employed methods based on thin-film mechanics to measure the drying stress and intercellular cohesion in the SC. The emulsifier molecules or moisturizing creams formulated with them were applied to a fully hydrated SC adhered to a glass substrate. In-plane stress developed in the SC during drying was then measured by tracking changes in the curvature of the glass substrate. The intercellular cohesion within the SC was measured by means of a double cantilever beam (DCB) set-up, where the treated or untreated SC was sandwiched between two substrates, and the delamination energy calculated by measuring the force required to drive a crack through the SC. Moisturizing cream diffusivity through the stratum corneum was measured by spectroscopic technique and related to internal SC stress and fracture energy.

RESULTS

We observe significant differences in the biomechanical behaviour of SC when moisturizing creams with different emulsifier molecules are applied on isolated stratum corneum ex vivo. The reduction in maximum stress varied between 12% and 26% depending on the emulsifier molecules used in the formulation. The intercellular cohesion and the diffusion of molecules in the formulated moisturizing creams through the SC were also found to be strongly dependent on the type of emulsifier molecule used in the formulation.

CONCLUSIONS

The biomechanical and barrier properties of the human stratum corneum show strong dependence on the emulsifier molecule used in the moisturizing creams, even when the creams included only ~3 weight% emulsifier molecules. Moreover, we found that the reduction in SC peak stress was strongly correlated with the formulation diffusivity into the SC. The moisturizing creams diffusing fastest into the SC had the largest reduction in peak stress and vice versa.

Ethanol-Based Disinfectants Containing Urea May Reduce Soap Sensitivity

BACKGROUND

The use of disinfectants is crucial to preventing the spread of nosocomial infections in health care workers. As many as 25 applications of hand disinfectants is a realistic default value during a working day. However, alcohol-based hand disinfectants may weaken skin barrier function and induce dryness and eczema, which decrease their acceptance.

OBJECTIVE

To evaluate the effect of ethanol-containing disinfectants with 5% urea on skin barrier function and on sensitivity to an irritant soap (sodium lauryl sulfate [SLS]).

METHODS

Twenty healthy volunteers treated one of their forearms twice daily for 17 days with an ethanol-containing gel with 5% urea. Two types of gels with urea were tested. Treatment was randomized to left or right forearm, and the contralateral forearm served as untreated control. Transepidermal water loss, skin capacitance (dryness), and sensitivity to SLS were evaluated.

RESULTS

Twice-daily application of the urea-containing ethanol gels lowered transepidermal water loss, prevented dryness, and reduced sensitivity to SLS compared with the untreated control skin.

CONCLUSIONS

Improved barrier function using this ethanol gel with urea may have relevance in daily disinfectant procedures.

Novel confocal Raman microscopy method to investigate hydration mechanisms in human skin

BACKGROUND

Skin hydration is essential for maintaining stratum corneum (SC) flexibility and facilitating maturation events. Moisturizers contain multiple ingredients to maintain and improve skin hydration although a complete understanding of hydration mechanisms is lacking. The ability to differentiate the source of the hydration (water from the environment or deeper skin regions) upon application of product will aid in designing more efficacious formulations.

MATERIALS AND METHODS

Novel confocal Raman microscopy (CRM) experiments allow us to investigate mechanisms and levels of hydration in the SC. Using deuterium oxide (D₂ O) as a probe permits the differentiation of endogenous water (H₂ O) from exogenous D₂ O. Following topical application of D₂ O, we first compare in vivo skin depth profiles with those obtained using ex vivo skin. Additional ex vivo experiments are conducted to quantify the kinetics of D₂ O diffusion in the epidermis by introducing D₂ O under the dermis.

RESULTS

Relative D₂ O depth profiles from in vivo and ex vivo measurements compare well considering procedural and instrumental differences. Additional in vivo experiments where D₂ O was applied following topical glycerin application increased the longevity of D₂ O in the SC. Reproducible rates of D₂ O diffusion as a function of depth have been established for experiments where D₂ O is introduced under ex vivo skin.

CONCLUSION

Unique information regarding hydration mechanisms are obtained from CRM experiments using D₂ O as a probe. The source and relative rates of hydration can be delineated using ex vivo skin with D₂ O underneath. One can envision comparing these depth-dependent rates in the presence and absence of topically applied hydrating agents to obtain mechanistic information.

Cosmetic benefit of a biomimetic lamellar cream formulation on barrier function or the appearance of fine lines and wrinkles in randomized proof-of-concept clinical studies

Objective

Two studies were designed to evaluate the potential cosmetic benefit of a biomimetic, niacinamide‐containing moisturizing cream for the first time in humans.

Methods

In both studies, healthy women were randomized to use two treatments, one for the left side of the body and one for the right, from three options: the test cream, a positive control or no treatment (use of standard cleanser only). Treatments were applied twice daily for 4 weeks to the face and forearms (Study 1) or the face only (Study 2). Instrumental and clinical skin assessments were performed by trained technicians. Study 1 involved tape stripping and a 5‐day no‐treatment (‘regression’) period at the end of the 4 weeks. Independent lay graders were asked to grade the skin texture of subjects in Study 2 from high‐resolution photographs.

Results

In Study 1 (n = 66), the test cream significantly decreased the transepidermal water loss (TEWL) values on the forearm, and in the cheek area of the face, relative to baseline and compared to no treatment, and increased skin Corneometer values. The improvements were partially retained during a subsequent 5‐day period of no treatment. Increases in TEWL values on skin subjected to tape stripping were significantly lower after 4 weeks of using the test cream compared to no treatment. In Study 2 (n = 72 subjects with visible signs of ageing), there was a favourable trend in the change from baseline of a skin roughness parameter, R_a, for the test cream compared to no treatment. There were statistically significant improvements in the Fitzpatrick wrinkle score compared to no treatment, decreases in TEWL and increased Corneometer values and Cutometer values (R5 elasticity parameter). Grading of high‐resolution images failed to detect the improvements in skin texture (defined as pores, smoothness and unevenness) for the test cream vs. no treatment. No treatment‐related serious or severe adverse events were reported.

Conclusion

Twice daily application of the test cream over 4 weeks had beneficial effects on skin barrier function, moisturization, wrinkle dimensions and elasticity compared to no treatment. These studies provide proof‐of‐concept evidence and highlight the cosmetic benefit of the biomimetic lamellar cream formulation. Study registration: NCT03216265, NCT03180645.

The Role of Every-Day Cosmetics in Altering the Skin Microbiome: A Study Using Biodiversity

As described in previous work, the use of synthetic chemical ingredients in modern cosmetics is postulated to be a cause of damage to the skin microbiome. The discovery that biodiversity on the human skin is currently the only reliable indicator of skin health, meant that for the first time, a mechanism to test for healthy skin was possible. Using this mechanism and in collaboration with The Medical University of Graz, who carried out the independent study, this work aimed to help answer whether modern day synthetic cosmetics are a main cause of long-term damage to the skin microbiome. Thirty-two human participants tested three different face washes for their effect on the skin’s microbial diversity, along with skin pH, moisture and TEWL (trans-epidermal water loss), washing twice-a-day for four weeks. The upper volar forearm of the volunteers was swabbed at the beginning, two weeks in and at the end of the four weeks. 16S rRNA sequencing was used. One leading ‘natural’ brand full of synthetic ingredients, a leading synthetic brand and a 100% natural face wash were used. Results give the first indications of a link between synthetic ingredients in a cosmetics product and its effect on skin microbiome biodiversity. It paves the way for future studies on the topic with a larger sample group, longer test period and standardised methodology to create a universal standard for testing the health of skin using benchmark diversity values. This can be used in the future to test the effectiveness of cosmetics or ingredients on skin health, leading to the restriction in cosmetics of products proven to harm the skin’s natural environment.

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.

A Pilot Study to Evaluate the Effects of Topically Applied Cosmetic Creams on Epidermal Responses

Application of exogenous products, such as creams, to the skin can result in subclinical changes in selected epidermal functions such as transepidermal water loss (TEWL), hydration, redness, and pH; these changes may lead to or contribute to irritation. Changes in skin surface inflammatory factors may provide further insight into this potential for irritation. The objective of this study was to evaluate the changes in epidermal properties and inflammatory mediators after 4 days of topical application of 2 different polymers formulated in cosmetic creams. Ten healthy volunteers (mean age ± SD: 20.0 ± 2.4 years) completed the study. TEWL, color, and pH were not significantly different after repeated application of these polymers. Hydration was significantly lower at sites treated with polymer A after 5 days. Significant increases in IL-1α, IL-1RA, and IL-1β were observed after cream application at sites treated with polymer A. This is the first study to apply noninvasive measurements to quantify subclinical changes in epidermal properties and inflammatory mediator expression before and after the application of a cosmetic product, which will allow for a more enhanced safety profile to be achieved.

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.

A functional mechanistic study of the effect of emollients on the structure and function of the skin barrier

BACKGROUND

Preventing relapses of atopic dermatitis (AD) through the regular use of topical products to repair the skin barrier defect is an emerging concept. It is still unclear if some commonly used emollients exert a positive effect on the skin barrier.

OBJECTIVES

To determine the skin barrier effects of emollients commonly prescribed in the U.K.

MATERIALS AND METHODS

Two cohorts of volunteers with quiescent AD undertook observer-blind forearm-controlled studies. The first cohort (18 volunteers) treated the volar side of one forearm with two fingertip units of Doublebase^™ gel twice daily for 4 weeks. The second cohort (19 volunteers) undertook the same regimen using Diprobase^® cream. Transepidermal water loss (TEWL), stratum corneum integrity and hydration, skin surface pH and redness were determined at the test sites before and after treatment.

RESULTS

Neither Diprobase^® cream nor Doublebase^™ gel significantly affected the underlying skin barrier function. Both emollients were associated with significantly increased skin surface pH immediately after application (by 0·8 ± 0·19 and 1·0 ± 0·18 units, respectively), and no erythema. Diprobase^® cream artificially and transiently (6 h) improved permeability barrier function by 2·9-3·1 g m^-2  h^-1 TEWL and increased skin hydration by 6·0-6·2 units. Doublebase^™ gel, containing humectants, was associated with a greater (between 10·1 and 13·0 units during the first 6 h) and more sustained increase in hydration, lasting more than 12 h following repeated use.

CONCLUSIONS

Diprobase^® cream and Doublebase^™ gel are not associated with skin barrier harm and appear to be appropriate for AD treatment. While displaying emollient properties, neither formulation displayed an ability to actively improve sustained skin barrier function.

Comparison of the Efficacy of Atopalm(®) Multi-Lamellar Emulsion Cream and Physiogel(®) Intensive Cream in Improving Epidermal Permeability Barrier in Sensitive Skin

INTRODUCTION

The management of sensitive skin, which affects over 60% of the general population, has been a long-standing challenge for both patients and clinicians. Because defective epidermal permeability barrier is one of the clinical features of sensitive skin, barrier-enhancing products could be an optimal regimen for sensitive skin. In the present study, we evaluated the efficacy and safety of two barrier-enhancing products, i.e., Atopalm (®) Multi-Lamellar Emulsion (MLE) Cream and Physiogel (®) Intensive Cream for sensitive skin.

METHODS

60 patients with sensitive skin, aged 22-40 years old, were randomly assigned to one group treated with Atopalm MLE Cream, and another group treated with Physiogel Intensive Cream twice daily for 4 weeks. Lactic acid stinging test scores (LASTS), stratum hydration (SC) and transepidermal water loss (TEWL) were assessed before, 2 and 4 weeks after the treatment.

RESULTS

Atopalm MLE Cream significantly lowered TEWL after 2 and 4 weeks of treatment (p < 0.01). In contrast, Physiogel Intensive Cream significantly increased TEWL after 2 weeks of treatment (p < 0.05) while TEWL significantly decreased after 4-week treatments. Moreover, both Atopalm MLE Cream and Physiogel Intensive Cream significantly increased SC hydration, and improved LASTS after 4 weeks of treatment.

CONCLUSION

Both barrier-enhancing products are effective and safe for improving epidermal functions, including permeability barrier, SC hydration and LASTS, in sensitive skin. These products could be a valuable alternative for management of sensitive skin.

FUNDING

Veterans Affairs Medical Center, San Francisco, California, USA, and NeoPharm Co., Ltd., Daejeon, Korea.

A controlled laboratory comparison of 4 topical skin creams moisturizing capability on human subjects

PURPOSE

This study compares human skin capacitance (moisture) readings after the application of 4 different, commercially available, topical skin creams.

SUBJECTS AND SETTING

Twenty-one subjects (15 women and 6 men) aged 49.38 ± 11.02) years (mean ± SD) participated. This study was conducted in a climate-controlled laboratory on healthy human subjects.

DESIGN

Randomized experimental study comparing 4 topical skin creams for their effect on human skin capacitance (moisture).

METHODS

Subject forearm skin was conditioned for 7 days prior to testing by washing with a standard soap and application of no other products. Each subject was marked with 5 test sites on the forearms. Sites on the volar surface of each subject's forearms were randomly assigned for application of 1 of 4 product pairs, consisting of a cleanser and a topical skin cream or a control site. A Corneometer was used to measure skin capacitance. Each site on the arms was cleaned and dried, tested again for moisture content, subjected to topical skin cream application, and finally tested again for moisture content. Changes were measured by subtracting the capacitance readings at baseline from values measured following topical skin cream application for each test site.

RESULTS

The mean change in capacitance was 13.9 for product 1, 10.3 for product 3, 8.7 for product 2, 1.6 for product 4, and 0.8 for the control site. The mean capacitance change in sites treated with product 1 (13.9 ± 8.0, mean ± SD) was significantly greater than all others. There was no difference between the change in capacitance of product 2 (mean = 8.7, SD = 4.9) and product 3 (10.3 ± 7.1) t(20) = 1.081, P = .293, nor between product 4 (1.6 ± 3.9) and the control site (0.3, ± 2.2) t(20) = 0.779, P = .445. The capacitance change of products 2 and 3 was greater than that of product 4 and the control site.

CONCLUSIONS

Commercially available topical skin creams vary in their impact on human skin capacitance. In this study, sites tested with product 1 had a greater skin capacitance reading than the other tested products; products 2 and 3 had similar capacitance readings. The results of this study provide an initial evaluation of topical skin creams that have varying impacts on skin capacitance.

Xerosis is associated with asthma in men independent of atopic dermatitis and filaggrin gene mutations

BACKGROUND

Epidermal filaggrin deficiency due to common filaggrin gene (FLG) mutations causes xerosis and strongly increases the risk of atopic dermatitis and even asthma. However, it is unknown whether xerosis independent of FLG mutations could also increase the risk of asthma.

OBJECTIVE

To evaluate whether generalized xerosis was associated with asthma, independent of atopic dermatitis and common FLG mutations in a cross-sectional study on adult Danes.

METHODS

A total of 3396 adults from the general population participated in a health examination. Lung function and serum-specific IgE levels to inhalant allergens were measured and information on xerosis and atopic diseases was obtained by means of a questionnaire. Participants were genotypes for the three most common FLG mutations in Northern Europeans: R501X, 2282del4 and R2447X.

RESULTS

Fully adjusted logistic regression analyses showed that asthma (either current or at some point in life) was significantly associated with reporting generalized xerosis (OR 1.32; 95% CI 1.02-1.72). The association was stronger in men (OR 1.79; 95% CI 1.13-2.84) when compared to women (OR 1.18; 95% CI 0.86-1.62). Furthermore, a significant association was observed between xerosis and 'allergic asthma' in men (OR 2.13; 95% CI 1.08-4.19).

CONCLUSION

Our findings indicate an association between xerosis and asthma in men independent of atopic dermatitis and FLG mutations. Both facilitated allergen sensitization and secondary degradation of filaggrin following T-helper cell 2 inflammation might be key elements to understanding this relationship.

Investigating skin barrier function utilizing reflectance NIR spectroscopy

Near Infrared Spectroscopy is seen as a potentially valuable technique for skin analysis, and has been employed by many previous studies to measure skin hydration, since it is competent of providing information regarding various functional groups including OH, CH and NH bands. The aim of this study was to investigate the capability of further utilizing this method by attempting to analyze skin barrier function as well as water content, through the evaluation of skin water uptake on two test sites, one untreated, and another treated with a high lipid moisturizer for a period of 7 days. Reflectance NIRS measurements were supported by capacitance readings obtained using the Corneometer® CM 825. Baseline recordings taken on the first day following treatment showed that more differences were observed between the treated and untreated sites in the regions belonging to, or are influenced by CH and NH groups rather than purely on the water bands. On the hand, moisture levels measured after placing a wet patch on the skin remained nearly equal for both sites but second derivative spectra showed that a clear contrast existed between absorbance heights at the water bands of the treated and untreated, suggesting that moisturizer use could have limited water uptake to a more superficial layer of the skin, whereas for the untreated site, the opposite would have been true and water was able to penetrate deeper. Overall, results here suggest that NIR spectroscopy can possibly provide valuable information not only on skin water contents but perhaps on other skin parameters such as barrier function.

A laboratory comparison between two liquid skin barrier products

Exposure of skin to friction and moisture is detrimental to skin health. The purpose of this experimental study was to investigate the ability of a cyanoacrylate polymer film to protect human skin against moisture and abrasion. A secondary purpose of this study was to compare this cyanoacrylate material to a traditional barrier film. Twelve healthy subjects participated in the wash-off resistance test to determine the percentage of dye that was left on the skin after repeated washing. Ten subjects participated in the abrasion test. Transepidermal water loss (TEWL) was measured before and after abrasion to determine the level of skin damage, as high water loss seen post-abrasion is indicative of skin damage post-abrasion. Skin treated with cyanoacrylate had significantly more dye remaining than sites treated with traditional film barrier or control sites. The change in TEWL was statistically lower for cyanoacrylate-treated areas.

Anti-aging cosmetics: facts and controversies

The authors review ageing in its extrinsic and intrinsic mechanisms, as well as the therapies available for improving its effects, and present some of the facts and controversies related to anti-aging cosmetics.

Characteristic differences in barrier and hygroscopic properties between normal and cosmetic dry skin. I. Enhanced barrier analysis with sequential tape-stripping

OBJECTIVE

Cosmetic dry skin often has a lower hydration level but a similar apparent barrier function, as measured by transepidermal water loss (TEWL), than that of the normal skin. To investigate the intrinsic difference in barrier property and moisture-holding ability between the cosmetic dry and normal skin, we developed a new clinical and data analysis procedure based on sequential tape-stripping with TEWL measurement, coupled with chemical analysis for protein and natural moisturizing factors (NMF) in the stratum corneum.

METHODS

A clinical study consisting of 64 healthy Caucasian female subjects with normal and cosmetic dry skin was conducted according to our clinical and data collection protocols. After the baseline visual dryness assessment, 20 tape-strips were placed and removed on each test site using D-Squame tapes. TEWL was measured at baseline and after the 5th, 10th, 15th and 20th tape-strips. All tapes were analysed for protein mass via chemical extraction and the Pierce BCA protein assay, as well as using an infrared densitometry device SquameScan 850A. The stratum corneum thickness and barrier quality (water transport resistance per thickness of the stratum corneum) were decoupled from the apparent barrier function using the TEWL and protein data.

RESULTS

A linear relationship between 1/TEWL and cumulative protein removal was observed for both normal and cosmetic dry skin. However, the slope of the linear relation was significantly steeper for normal skin, and significantly more protein was removed from cosmetic dry skin. The results showed that on average, the barrier quality of the stratum corneum of the normal skin is about 40% higher than that of the dry skin, whereas the stratum corneum of the dry skin is about 30% thicker than that of the normal skin. In addition, the amount of SC removal in sequential tape-stripping is generally non-uniform.

CONCLUSION

Our results demonstrated that there are characteristic differences in the barrier property between normal and cosmetic dry skin. In comparison to the normal skin, the stratum corneum of the cosmetic dry skin is considerably thicker, however, with a lower barrier quality. The results also showed that the amount of the SC removal in sequential tape-stripping is generally non-uniform. Therefore, the number of tape strips is not a good indicator for the tape-stripping depth.