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

Short- and long-term effects of single and repetitive glove occlusion on the epidermal barrier

The aim of this study was to analyse the occlusive effects of glove materials (polyvinyl chloride, natural rubber latex) on epidermal barrier function and to relate the findings to the definitions of wet work in the current German ordinance on hazardous substances (2007) and in the German technical regulations on hazardous substances (TRGS 401; 2008). Short-term effects of wearing gloves once for 4 h, as well as the long-term effects of wearing gloves for 4 h daily for 7 days were assessed in a group of 20 healthy volunteers using non-invasive methods (transepidermal water loss (TEWL), capacitance, skin colour, skin surface pH). Data were collected 30 min and 3 h after single use, as well as 1 day after a 1-week application. TEWL and capacitance data showed hyperhydration of the horny layer 30 min after a 4-h occlusion as compared to baseline (p < 0.05). Three hours later, full recovery to basal values was observed. Additionally, a significant long-term effect after daily occlusion for 4 h for 7 days could not be demonstrated. In current literature, there is controversial evidence concerning the effects of glove occlusion. This study could not verify significant damage to skin barrier after 7 days of repeated occlusion 4 h daily in healthy volunteers. These findings require further discussion regarding the definitions in the current German ordinance on hazardous substances and in the TRGS 401.

Quantitative assessment of combination bathing and moisturizing regimens on skin hydration in atopic dermatitis

Standard recommendations for skin care for patients with atopic dermatitis stress the importance of skin hydration and the application of moisturizers. However, objective data to guide recommendations regarding the optimal practice methods of bathing and emollient application are scarce. This study quantified cutaneous hydration status after various combination bathing and moisturizing regimens. Four bathing/moisturizer regimens were evaluated in 10 subjects, five pediatric subjects with atopic dermatitis and five subjects with healthy skin. The regimens consisted of bathing alone without emollient application, bathing and immediate emollient application, bathing and delayed application, and emollient application alone. Each regimen was evaluated in all subjects, utilizing a crossover design. Skin hydration was assessed with standard capacitance measurements. In atopic dermatitis subjects, emollient alone yielded a significantly (p < 0.05) greater mean hydration over 90 minutes (206.2% baseline hydration) than bathing with immediate emollient (141.6%), bathing and delayed emollient (141%), and bathing alone (91.4%). The combination bathing and emollient application regimens demonstrated hydration values at 90 minutes not significantly greater than baseline. Atopic dermatitis subjects had a decreased mean hydration benefit compared with normal skin subjects. Bathing without moisturizer may compromise skin hydration. Bathing followed by moisturizer application provides modest hydration benefits, though less than that of simply applying moisturizer alone.

The Physicochemical Characterization and In Vitro/In Vivo Evaluation of Natural Surfactants-based Emulsions as Vehicles for Diclofenac Diethylamine

Two sugar-based emulsifiers, cetearyl alcohol & cetearyl glycoside and sorbitan stearate & sucrose cocoate, known as potential promoters of lamellar liquid crystals/gel phases, were investigated in order to formulate an optimal vehicle for amphiphilic drug - diclofenac diethylamine (DDA). Physico-chemical characterization and study of vehicle's physical stability were performed. Then, the in vitro DDA liberation profile, dependent on the mode of drug incorporation to the system, and the in vivo, short-term effects of chosen samples on skin parameters were examined. Droplets size distribution and rheological behavior indicated satisfying physical stability of both types of vehicles. Unexpectedly, the manner of DDA incorporation to the system had no significant influence on DDA release. In vivo study pointed to emulsion's favorable potential for skin hydration and barrier improvement, particularly in cetearyl glycoside-based vehicle.

Measuring the effects of topical moisturizers on changes in stratum corneum thickness, water gradients and hydration in vivo

BACKGROUND

Moisturizers are the most commonly used topically applied product for the treatment of dry skin conditions. They affect many properties and functions of the stratum corneum but some moisturizers have been reported to be detrimental to barrier function. Stratum corneum barrier function is a composite of its total structure and thickness but few studies have taken this into account. As a biosensor, the stratum corneum (SC) will change its structure in response to treatment and a swelling effect has been clearly demonstrated by skin hydration. Recently several moisturizing agents have been shown to have an effect on SC swelling behaviour with conflicting results. However, there is a paucity of data reported for measuring the effects of long-term usage of moisturizers on SC thickness in vivo as, until recently, traditional techniques did not have the resolution to measure the effects of moisturizers on nonpalmoplantar body sites. The development of confocal Raman spectroscopy for use in human subjects provides noninvasive, real-time, in vivo measurement of SC water concentration profiles and we have also used this state of the art equipment to measure the effect of the long-term use of moisturizers on SC thickness for the first time.

OBJECTIVES

To validate the use of confocal Raman spectroscopy (CRS) to measure SC thickness and then use it to investigate the short- and long-term effects of moisturizers (one of which is known to improve SC barrier function) on SC thickness, water gradients and hydration.

METHODS

Two studies were conducted: (i) to validate the use of CRS for measuring SC thickness through comparison with optical coherence tomography (OCT); and (ii) once validated to use CRS to measure the long-term effects of three commercially available moisturizers (A, B, C) on SC thickness and water gradients, together with total hydration, over a 3-week period (2 weeks of treatment and 1 week regression) and compare the spectroscopy-derived hydration value with instrumentally derived capacitance hydration values.

RESULTS

(i) A strong, positive correlation in SC thickness was obtained between CRS and OCT (OCT-derived thickness = 0.96 x CRS-derived thickness, r(2) = 0.93; P <0.0001). OCT was shown, however, to have a lower resolution than CRS in distinguishing SC thickness on thinner nonpalmoplantar body sites. Using the CRS method, differences in SC thickness were readily apparent on different body sites (cheek 12.8 +/- 0.9 microm, volar forearm 18.0 +/- 3.9 microm, leg 22.0 +/- 6.9 microm). (ii) Examining the effects of moisturizers in a blinded, randomized 3-week study in human volunteers (n = 14) demonstrated that only one commercially available formulation (A) changed SC water gradients, thickness and hydration as measured by CRS. These hydration data did not directly correlate with capacitance hydration values.

CONCLUSIONS

(i) In vivo CRS was validated as a technique to measure SC thickness on both palmoplantar and, particularly, on nonpalmoplantar skin sites. (ii) Moisturizers improve skin moisturization but in this study only formulation A improved SC thickness, water gradients and hydration as measured by CRS. We hypothesize that this was due to compositional differences between the products. We believe that niacinamide (nicotinamide, vitamin B(3)) is probably contributing significantly to this effect, as it has been proven to increase epidermal lipogenesis and SC barrier function in other studies. These results show that by using CRS, we were able for the first time to determine the effect of moisturizer on multiple SC barrier endpoints including SC thickness, and water content as a function of depth and total SC water content.

Cosmetic formulations containing Lithospermum erythrorhizon root extract show moisturizing effects on human skin

Retention of water in the stratum corneum of skin epidermis plays an important role in regulation of skin function. Loss of water may decline skin appearance gradually and lead to irregular skin disorders. The root extract of Lithospermum erythrorhizon (LES) is known for its various pharmacological activities. However, the potential skin care effect of LES is not clear. The aim of this study was to evaluate the moisturizing efficacy and skin barrier repairing activity of LES. For this study, 30 healthy Asian females (age 20-30) with healthy skin had applied the test emulsions twice daily over a period of 28 days. The skin properties were measured by skin bioengineering techniques. Our preliminary results indicated that LES show moisturizing effect on skin hydration in a time- and dose-dependent pattern, and the maximum increase in skin humidity was 11.77 +/- 1.18% for emulsion LES5.00. Particularly, LES-containing emulsions significantly improve skin barrier function by decreasing the value of transepidermal water loss (TEWL) in a time- and dose-dependent pattern, and the maximum decrease in TEWL value was 7.68 +/- 0.79% for emulsion LES5.00. Taken together, our data demonstrate that LES is more effective in increasing skin humidity and decreasing the TEWL values, indicating the potential skin care effects of LES.

Increase of skin-ceramide levels in aged subjects following a short-term topical application of bacterial sphingomyelinase from Streptococcus thermophilus

Several studies have demonstrated that ceramides play an essential role in both the barrier and water-holding functions of healthy stratum corneum, suggesting that the dysfunction of the stratum corneum associated with ageing as well that observed in patients with several skin diseases could result from a ceramide deficiency. In a previous study our group reported a significant increase in skin ceramide levels in healthy subjects after treatment in vivo with a cream containing a preparation of Streptococcus thermophilus. The presence of high levels of neutral sphingomyelinase activity in this organism was responsible for the observed increase of stratum corneum ceramide levels, thus leading to an improvement in barrier function and maintenance of stratum corneum flexibility. The aim of the present work is to investigate the effects of the topical treatment of a Streptococcus thermophilus-containing cream on ceramide levels of stratum corneum of healthy elderly women. The ceramide levels, transepidermal water loss and capacitance were evaluated on stratum corneum sheets from the forearms of 20 healthy female subjects treated with a base cream or the same cream containing a sonicated preparation of the lactic acid bacterium Streptococcus thermophilus. A 2-week topical application of a sonicated Streptococcus thermophilus preparation led to significant and relevant increase of stratum corneum ceramide levels. Moreover, the hydration values of the treated forearm of each subject was significantly higher than control sites. These results suggest that the experimental cream was able to improve the lipid barrier and to increase a resistance against ageing-associated xerosis.

Skin irritation and sensitization: mechanisms and new approaches for risk assessment. 1. Skin irritation

Cutaneous irritation presents a major health problem with serious social and occupational impact. The interaction between an irritant and the human skin depends on multiple factors: the intrinsic properties and the nature of the irritant itself, and specific individual- and environment-related variables. The main pathological mechanisms of irritancy include skin barrier disruption, induction of a cytokine cascade and involvement of the oxidative stress network; all of them resulting in a visible or subclinical inflammatory reaction. In vivo, different non-invasive parameters for the evaluation of skin irritation and irritant potential of compounds and their specific formulations have been introduced, such as epidermal barrier function, skin hydration, surface pH, lipid composition, skin colour and skin blood flow. The diverse physiological changes caused by irritating agents require implementation of a multiparametric approach in the evaluation of cutaneous irritancy.

Cosmetic effectiveness of topically applied hydrolysed keratin peptides and lipids derived from wool

BACKGROUND/PURPOSE

Skin moisturisation, elasticity, feel and appearance can all be improved through the topical application of protein hydrolysates. Recent studies suggest that supplementing intercellular lipids of the stratum corneum can enhance the functioning of the skin.

METHODS

In this study, a hydrolysed keratin peptide (molecular weight <1000 Da) was prepared from wool and tested on skin in two different formulations: an aqueous solution and an internal wool lipids (IWL) liposome suspension. In vivo long-term studies were performed to evaluate the water barrier function of the skin after topical application of different formulations. During the treatment period, hydration and elasticity were determined. A sorption-desorption test was also performed to assess the hygroscopic properties and water-holding capacity of the different treated skin sites.

RESULTS

Significant differences were found between the control and treated sites, with the treated areas showing an increase in hydration and elasticity as a result of keratin peptide application. Measurements also indicated that the keratin formulations reinforce the skin barrier integrity, improving its water-holding capacity.

CONCLUSION

A combination of the keratin peptide with the IWL showed beneficial effects, indicating that this combination is suitable for designing new cosmetics products.

Kinetics of moisturizing and firming effects of cosmetic formulations

The assessment of cosmetic efficacy is rarely performed in studies comparing different concentrations of active compounds. The aim of the present study was to determine the skin hydrating and the skin firming dose-response effects of cosmetic formulations enriched in compounds derived from algae and fish collagen. A series of factors were studied including the type of formulation (cream or serum), the concentration in active ingredients, the effect of repetitive applications, as well as any residual effect of the formulations after stopping their applications. The serum enriched in marine compounds showed a better moisturizing effect in short term. The cream appeared more active later, particularly following repeat applications. A sustained tensor (firming) effect was observed during treatment with both the lotion and the cream. However, no remnant firming effect was perceived after stopping treatment.

Protection effect of cosmetics on human skin under simulated rigorous environment

BACKGROUND/PURPOSE

The efficacy of cosmetics on human skin measured under normal mild laboratory environment might be discounted by exterior environment factors such as wind, UV exposure, etc. Few studies have focused on the 'genuine' efficacy of cosmetics on human skin during exposure to external rigorous environment. The aim of this study was to develop a model for the evaluation of the efficacy of cosmetics on human skin under simulated rigorous environment.

METHODS

We measured skin water content and transepidermal water loss (TEWL) before and after products application under simulated windy and sub-erythema UV exposure treatment in a constant temperature and humidity laboratory.

RESULTS

The results showed that the products had higher water content and lower TEWL at 2, 4 and 8 h of products application, and ameliorated the skin moisturization situation after a 3-week continuous use of the products. In addition, the products might protect the skin to maintain the normal water content and TEWL under the simulated windy or sub-erythema UV exposure treatment in our laboratory when compared with untreated area.

CONCLUSION

Our data indicate that this model may provide a more accurate evaluation for the genuine moisturizing effect of cosmetics under external natural climate.

Biometrology of physical properties of skin in thyroid dysfunction

OBJECTIVE

There is ample clinical evidence that skin is responsive to physiopathological levels of circulating thyroid hormones. The aim of the study was to assess some physical changes of the skin in the presence of moderate thyroid dysfunction.

SETTING

University Hospital.

PATIENTS AND METHODS

A total of 119 adults suffering from hypothyroidism or hyperthyroidism and 60 healthy controls were enrolled in this study. Hormonal dosages (TSH, fT3, fT4) were assessed in the serum. A series of biometrological assessments were also performed on the volar and dorsal aspects of the forearms. These included electrometric assessments (Nova Dermal Phase Meter, Corneometer), evaporimetry (Tewameter)), colorimetry (Mexameter), ultrasound shear wave propagation (Reviscometer) and squamometry X. Correlations were searched between each of the serum hormonal dosages and each of the biometrological parameters.

RESULTS

The hormonal changes in the untreated patients with thyroid dysfunction were modest in intensity. A few outlier values with regard to the normal range were found for each biometrological parameter. No correlations were found between fT3 or fT4 and each of the physical parameters. By contrast, significant negative linear correlations were found between thyroid-stimulating hormone (TSH) and skin hydration measured by the Corneometer and the Nova DPM.

CONCLUSION

This multipronged exploratory study shows that direct or indirect effects of TSH may influence the stratum corneum hydration. This correlation seemed very sensitive, as no other specific biophysical parameter was significantly correlated with the thyroid hormonal concentrations in the serum. However, our findings do not exclude the possibility of some other skin changes supervening in case of more severe thyroid dysfunction. The mechanism by which TSH alters the stratum corneum hydration is yet unknown.

Barrier function and water-holding and transport properties of infant stratum corneum are different from adult and continue to develop through the first year of life

Skin water barrier development begins in utero and is believed to be complete by week 34 of gestational age. The goal of this investigation was to assess the dynamic transport and distribution of water of the stratum corneum of infants and compare it to those of adults. The interaction of water with the stratum corneum was assessed by measuring capacitance, transepidermal water loss (TEWL), rates of absorption-desorption as well as Raman spectra as a function of depth (a total of 124 infants (3-12 months) and 104 adults (14-73 years)). The results show that capacitance, TEWL, and absorption-desorption rates had larger values consistently for infant stratum corneum throughout the first year of life and showed greater variation than those of adults. The Raman spectra analyzed for water and for the components of natural moisturizing factor (NMF) showed the distribution of water to be higher and have a steeper gradient in infants than in adults; the concentration of NMF was significantly lower in infants. The results suggest that although the stratum corneum of infants may appear intact shortly after birth (<1 month), the way it stores and transports water becomes adult-like only after the first year of life.

Influence of polyol and oil concentration in cosmetic products on skin moisturization and skin surface roughness

BACKGROUND/PURPOSE

The purpose of this study is to investigate the optimum combination of polyols and oils in moisturizing cosmetic products to improve the human skin moisturization and skin surface roughness. Polyols and oils are essential ingredients in skin care products, but it is still not understood how their concentrations affect their efficacy and sensory properties on human skin. We investigated the effect of polyol and oil concentration on skin properties by noninvasive methods.

METHODS

The polyols consisted of glycerin and butylenes glycol in a ratio of 1:1 and the oils consisted of equal parts of hydrogenated polydecene, cethyl ethylhexanoate and pentaerythrityl tetraethylhexanoate. All cosmetic products were made in O/W emulsions in concentrations ranging from 0% to 30% for polyols and from 0% to 35% for oils. We investigated the effect on water content and skin surface roughness on the forearm after application of the cosmetic products. The skin water contents were measured by a Corneometer CM825 and the skin surface roughness by visual coring of skin surface biopsies in the scanning electron micrographs.

RESULTS

In the first study, we found that the water content of the skin correlated highly with the polyol (up to 30%) and oil (up to 12%) concentrations, respectively. At two hours after application, the correlation coefficients were 0.971 and 0.985, respectively (P<0.01). Skin surface roughness not only showed a strong concentration dependence on polyols and oils (up to 6%). In the second study, we investigated the optimum combination of polyols and oils to improve the skin moisturization and skin surface roughness by the Response surface methodology. The water content of the skin surface was high in the ratio of polyol to oil (30:12 and 25:30). The skin surface roughness was improved considerably in the ratio of polyols to oil (30:6 and 30:35).

CONCLUSIONS

Our results indicated that the skin surface properties were improved in the different ratios of their concentrations because they are influenced by not one ingredient but the interaction between polyols and oils. In this study, we could recommend the optimum concentration of polyols and oils to improve the skin surface properties. Further studies will be performed with other ingredients such as surfactants, lipids and so on.

Evaluation of a new pressure ulcer preventive dressing containing ceramide 2 with low frictional outer layer

AIM

This paper is a report of an evaluation of the effectiveness of a newly developed dressing for preventing persistent erythema and pressure ulcer development and improving the water-holding capacity without increasing the skin pH in bedridden older patients.

BACKGROUND

Shear forces and skin dryness play important roles in persistent erythema and pressure ulcer development. To eliminate these risks, we developed a dressing to reduce shear forces and improve the water-holding capacity. However, the effects of this dressing in clinical settings remain unknown.

METHOD

An experimental bilateral comparison study was conducted at a hospital in Japan in 2004 with 37 bedridden older patients at risk of pressure ulcer development. The dressing was randomly applied to the right or left greater trochanter for 3 weeks. No dressing was applied to the opposite side as a control. The skin was monitored weekly during the 3-week application for persistent erythema and pressure ulcer development. Skin hydration and pH were also assessed during the intervention and for 1 week after dressing removal.

FINDINGS

The incidence of persistent erythema was significantly lower in the intervention area than the control area [P = 0.007, RR 0.18 (95% CI: 0.05-0.73) and NNT 4.11 (2.50-11.63) ]. No pressure ulcers occurred in either the intervention or control area. Skin hydration increased significantly during dressing application and remained high after removal (P < 0.001) relative to the control area. Skin pH decreased significantly during the application (P < 0.001) but returned to control levels after removal (P = 0.38).

CONCLUSION

This safe and effective dressing can be used for patients with highly prominent bones and dry skin to prevent pressure ulcers.

Moisturizing and antisebum effect of cosmetic application on facial skin

BACKGROUND

Water content of the stratum corneum and skin surface lipids are important factors in the appearance and function of skin. High water content and low sebum secretion are considered main features of fair skin. Aim This paper aims to study the change of skin physiological parameters after cosmetic application.

METHODS

The skin water content, transepidermal water loss, and skin sebum secretion on different regions of the facial skin before and after the cosmetic application were measured using Corneometer, Tewameter, and Sebumeter, respectively.

RESULTS

The cosmetics kept higher water content and lower transepidermal water loss, at the same time lower sebum secretion 4 and 8 h after the cosmetic application, compared with those before it. The situation was maintained in the following 3-week continuous use of the cosmetics.

CONCLUSION

The cosmetic application on human facial skin could provide some moisturizing effect and at the same time some antisebum effect according to different regions on facial skin, which favored the maintenance of good skin physiological function after applying skin care products.

Assessment of atopic eczema: clinical scoring and noninvasive measurements

BACKGROUND

Clinical scoring systems are widely used in clinical trials of atopic eczema (AE), while noninvasive methods are more often used for research purposes. Positive correlations between the two types of methods may be used in support of the validity of both in a clinical context. Few studies are available of the association between clinical scores and instrumental assessment of disease severity obtained with noninvasive instruments.

OBJECTIVES

To compare clinical scores in AE with biometric data in AE.

METHODS

Transepidermal water loss, stratum corneum hydration, erythema, scaling and subepidermal oedema were measured. 'Scoring of Atopic Dermatitis (SCORAD)', 'Eczema Area and Severity Index (EASI)' and 'Atopic Dermatitis Severity Index (ADSI)' were used for clinical scores. Two assessments at 6-month intervals at the antecubital fossa, dorsal forearm and popliteal fossa in 101 patients with AE and 30 controls were carried out.

RESULTS

Significant correlations were found within the clinical scores (P < 0.0001 and r = 0.85-0.91) and between instruments and clinical scores (P < 0.0001 and r = 0.61-0.79).

CONCLUSIONS

The various instruments and clinical scores showed internal agreement and noninvasive methods correlated significantly with the three different clinical scorings systems. This observation suggests that both methods provide data of clinical (scores) and biological (instrumental measures) relevance, and may be useful in future studies of AE. It is speculated that combined measures including scores and selected instruments may be particularly useful.

Do moisturizers work?

Moisturizers are used on large body surfaces to maintain the smoothness of the skin and to break the dry-skin cycle. Many healthcare professionals and patients overlook the importance of moisturizers and do not consider them to be 'active' treatments. However, evidence from clinical and experimental studies shows that moisturizers enhance both the smoothness and hydration of skin. Different moisturizers have different ingredients, and each may have a different mode of action. Some smooth the skin, others affect barrier function. Some enhance barrier function in both diseased and normal skin. Others impair barrier function in both diseased and normal skin. Defective barrier function may trigger the development of eczema. The composition of a particular moisturizer should reflect its desired therapeutic effect, i.e. a moisturizer to diminish dryness may need different ingredients from those required to improve barrier function. The content of excipients, such as emulsifiers, chelating agents and antioxidants, may have greater impact than is commonly believed. Greater tailoring of moisturizers will improve their efficacy. Confidence in the therapeutic effects of moisturizers will be enhanced by well-designed randomized controlled trials.

Chronophysiologie circadienne du cuir chevelu

Biological rhythms are numerous and vary according to periodicity and amplitude. Variations over the course of a day, particularly circadian rhythms have been reported in the skin of the face and forearms. However, little information is available about daily biorhythms of the scalp. The aim of the present study was to explore the chronophysiology of the scalp. We report a series of diurnal rhythms in 8 Caucasian men using the plexogram method at 4-h intervals over a 5-day period. Statistically significant biorhythms were found for the colour, hydration, barrier function and pH of the skin, and for the sebum excretion as well. The early afternoon was the time of maximum increase in redness, hydration, pH and sebum output, combined with decreased skin barrier function. The amplitude of some of these biorhythms was so discrete that their clinical relevance remained uncertain even when they appeared statistically significant. In view of the apparent synchronization between them, it is likely that a central oscillator exerts a major influence. However, only rare subjects exhibited biorhythms for all the considered physiological parameters. Hence, peripheral reactivity and/or environmental synchronizers also play an important role to define the good and bad respondors to the potential biorhythms of each individual parameter.

Functional Assessment of a Skin Care System in Patients on Chemotherapy

BACKGROUND/PURPOSE

Cancer patients undergoing chemotherapy frequently experience skin problems such as xerosis. The aim of this study was to verify whether a concomitant treatment with an acidic washing and an acidic emollient (both pH 5.5) can significantly improve the quality of the skin in such patients.

METHODS

30 adult patients on chemotherapy experiencing dry and sensitive skin were included in a controlled, monocentric, 3-week treatment trial. One forearm served as a test site, the other one remained untreated. Noninvasive biophysical measurements were performed at baseline, on days 7, 14 and 21, along with clinical evaluation of the skin symptoms.

RESULTS

After a 3-week treatment, a significant increase in stratum corneum hydration was recorded in the treated site (p < 0.001). Reduced transepidermal water loss values, consistent with a restored barrier function, were obtained (p < 0.001). Casual sebum levels as measured by sebumetry showed a significant increase (p < 0.03). All skin symptoms investigated revealed a considerable improvement over 3 weeks.

CONCLUSION

Controlled and regular use of a skin care system, especially an acidic one, improved skin physiology in patients undergoing chemotherapy.

In vivo assessment of Ectoin: a randomized, vehicle-controlled clinical trial

The aim of the study was to assess an Ectoin formulation with regard to the antiageing properties. The study was designed as a monocentric, randomized, double-blind application test, in order to ensure the compatibility and the efficacy of Ectoin in comparison to a vehicle emulsion. A total of 104 voluntary healthy female test subjects were included in the study. Moisturizing properties as well as other parameters of skin ageing, like skin surface structure and skin elasticity, were determined for treatment A (vehicle) and treatment B (with 2% Ectoin) versus an untreated control. Statistical evaluations according to the Wilcoxon rank-sum test indicate a general preference for the Ectoin treatment by the test subjects in both the application and the efficacy tests. None of the participating test subjects had any side effects throughout the study. In terms of antiageing properties, previous in vitro studies could be confirmed by this clinical trial, clarifying that the natural cell protection concept of Ectoin is transferable to skin care with manifold benefits.

Effect of room humidity on the formation of fine wrinkles in the facial skin of Japanese

BACKGROUND/PURPOSE

Changes in humidity are commonly known to influence the condition of the skin. Previous studies of the skin dealt with variations in relative humidity (RH) either through statistical analysis or by maintaining room humidity at a constant level; however, the range of humidity and the length of acclimation varied in each study. This study aimed to determine whether the generally used ranges of RH are truly acceptable for studies of human skin.

METHODS

Skin conductance, elasticity and fine wrinkles were assessed on the eyelids of 20 volunteers, first after acclimation for 30 min in a high-humidity room (70% RH) and again after acclimation for 30 min in a low-humidity room (40% RH).

RESULTS

The study found significant decreases in skin conductance and elasticity and significant increases in fine wrinkles after acclimation to low humidity compared with high humidity.

CONCLUSION

These results indicate that even a 30% difference in RH can affect skin properties in 30 min. The importance of humidity stabilization and the necessity of acclimation to the humidity, particularly when the study concerns wrinkles, were thus confirmed.

Comparative Effect of Tacrolimus and Betamethasone Valerate on the Passive Sustainable Hydration of the Stratum Corneum in Atopic Dermatitis

BACKGROUND

There is ample evidence that the skin barrier function is altered in atopic dermatitis. Little information is available about the effect of topical corticosteroids and calcineurin inhibitors on this function.

PURPOSE

To assess the water content and its rate of accumulation in the stratum corneum of atopic patients using an indirect electrometric method while on tacrolimus or betamethasone valerate treatment.

METHOD

Twenty-one patients with moderate atopic dermatitis affecting both forearms completed this double-blind randomized study. One forearm was treated twice daily for 3 weeks with 0.1% tacrolimus ointment. The other forearm was similarly treated with 0.12% betamethasone valerate ointment. Electrometric measurements were made under continuous occlusion secured by a Nova Dermal Phase Meter sensor probe. Assessments were performed at inclusion, after the 3-week treatment and after a further 3-week follow-up out of treatment.

RESULTS

During treatment, both compounds yielded a similar improvement in skin barrier function. Indeed, under probe occlusion, the rate of water accumulation was significantly decreased. This improvement was sustained after stopping the tacrolimus treatment. By contrast, the benefit was in part lost at the site that had been treated by betamethasone valerate.

CONCLUSION

The difference in the effect of the 2 compounds may be due to the negative influence of betamethasone valerate on the epidermal metabolism leading to progressive atrophy of the tissue. The better preservation of the skin barrier function after stopping tacrolimus treatment may help retarding relapses of atopic dermatitis.

An alkylpolyglucoside surfactant as a prospective pharmaceutical excipient for topical formulations: The influence of oil polarity on the colloidal structure and hydrocortisone in vitro/in vivo permeation

There is a growing need for research into new skin- and environment-friendly surfactants. This paper focuses on a natural surfactant of an alkylpolyglucoside type, which can form both thermotropic and lyotropic liquid-crystalline phases. The aim of this study was to relate some physicochemical properties (characterised by polarisation and transmission electron microscopy, thermal analysis and rheology) of the three formulations based on cetearyl glucoside and cetearyl alcohol, to the results of in vitro and in vivo bioavailability of hydrocortisone (HC). The three formulations contained oils of different polarity (medium chain triglycerides: MG, isopropyl myristate: IPM and light liquid paraffin: LP), respectively. In vitro permeation was followed through the artificial skin constructs (ASC), while the parameters measured in vivo were erythema index: EI (using instrumental human skin blanching assay), transepidermal water loss (TEWL) and stratum corneum hydration (SCH). The vehicles based on cetearyl glucoside and cetearyl alcohol showed a complex colloidal structure of lamellar liquid-crystalline and lamellar gel-crystalline type, depending on oil polarity. Rheological profile of the vehicle was directly related to the in vitro profile of the HC permeation. In vivo results suggested that the vehicle with MG retarded the HC permeation, whereas less polar IPM and non-polar LP enhanced it. It is suggested that the enhancement is achieved either by a direct interaction with lipid lamellae of the SC or indirectly by improving skin hydration. There were no adverse effects during in vivo study, which indicates a good safety profile of this alkylpolyglucoside surfactant.

Early-life risk factors for occurrence of atopic dermatitis during the first year

OBJECTIVE

In a prospective birth cohort study, we sought to identify perinatal predictors of the occurrence of atopic dermatitis in the first year of life.

METHODS

Associations of family history, infection during pregnancy, cord blood cytokine concentrations, and skin function parameters with atopic dermatitis were analyzed. Stratum corneum hydration was measured with an impedance meter until 5 days after delivery and again at 1 month.

RESULTS

Complete data were obtained for 213 infants, including 27 diagnosed by a physician as having atopic dermatitis during their first year and 26 diagnosed as having infantile eczema during their first month. The risk of atopic dermatitis during the first year of life was related to maternal atopic dermatitis, lower concentrations of macrophage inflammatory protein-1beta in cord blood, and greater skin moisture in the surface and stratum corneum of the forehead and cheek at 1 month of age but not to viral or bacterial infection during pregnancy or breastfeeding. Paternal hay fever was associated negatively with the development of atopic dermatitis. High concentrations of interleukin-5, interleukin-17, and macrophage chemotactic protein-1 and only surface moisture in the cheek were associated with greater risk of infantile eczema in the first month.

CONCLUSIONS

The association of atopic dermatitis in infancy with reduced neonatal macrophage inflammatory protein-1beta levels suggests a link with immature immune responses at birth. Stratum corneum barrier disruption in atopic dermatitis may involve impairment of cutaneous adaptation to extrauterine life. The majority of risk factors had different effects on infant eczema and atopic dermatitis, indicating different causes.

Visualization technique for water content distribution of skin tissue by dualband polarization imaging

The advanced imaging technique for visualizing two-dimensional water content distribution in the stratum corneum of human skin is proposed. The method involves two elemental principles of spectral filtering and imaging with polarization control. It is found in the in vivo experiment in the visible and the near-infrared range that the reflectance spectra of skin tissue in the wavelength range shorter than 600 nm are affected largely by water content. The polarization imaging technique is, on the other hand, introduced for emphasizing the subsurface reflection from skin tissue. The superficial reflection can be separated from the deeply penetrated light by controlling the orientations of the polarizer and the analyzing polarizer put in front of the light source and the imaging device, respectively. The combination of spectral bandpass filtering and polarization imaging enables us to acquire the water content distribution of the stratum corneum.

Comparison of the effect of glycerol and triamcinolone acetonide on cumulative skin irritation in a randomized trial

BACKGROUND

So-called anti-irritants are added to cosmetic formulations because of their alleged beneficial effect on irritated skin. Documentation for these claims is often limited. However, glycerol has shown anti-irritant properties in experimentally induced irritation from sodium lauryl sulfate and nonanoic acid (NON). This study was designed to further substantiate that glycerol added to cosmetic formulations has an anti-irritant effect on experimentally induced skin irritation.

OBJECTIVE

We sought to compare glycerol with triamcinolone acetonide as treatments for cutaneous irritation in human volunteers.

METHODS

Irritation was induced by 3 daily arm washes for a week with 10% sodium lauryl sulfate on one arm and 30% NON on the other. To maintain irritation, for the next 12 days volunteers washed their arms twice daily with the irritants. Treatments were applied immediately after washing. The treatments (including vehicle and no treatment) were randomized to sites using a Latin square design. The reactions were evaluated clinically and instrumentally.

LIMITATIONS

Study was designed to only detect potent anti-irritants.

CONCLUSION

Glycerol reduced the irritant effect of both sodium lauryl sulfate and NON, whereas triamcinolone acetonide appeared to have beneficial effect only on the irritation induced by NON. The study provided experimental documentation for the claim that glycerol has anti-irritant effect in a cosmetic formulation.

Estimation of water content distribution in the skin using dualband polarization imaging

BACKGROUND/PURPOSE

A new enhancement imaging technique for visualizing two-dimensional distribution of water content in human tissue is proposed based on optical properties such as reflectance spectra and the scattering from the skin surface.

METHODS

The method consists of two fundamental functions: spectral filtering for estimating skin hydration and polarization control for the appropriate measurement depth. Spectral filtering is simply achieved by utilizing the bandpass filters, whereas the measurement depth control is performed by changing the polarization directions in front of a light source and a detector.

RESULTS

The combined method of spectral filtering and polarization imaging effectively visualized the water content distribution in skin as a shading on a composed black and white image. The result was compared with the measured value of the capacitance method, and the result of the proposed method was validated.

CONCLUSION

Our results suggest that the proposed method enhances the scattering property in the skin according to the water content. Detailed discussions are given.

Skin capacitance imaging of acne lesions

BACKGROUND

Little information is available about specific functional characteristics of skin in acneic patients.

OBJECTIVE

To determine a capacitance mapping of lesional skin in acne in order to predict drug affinity according to the hydrophilic-lipophilic characteristics.

METHOD

Skin capacitance imaging based on silicon image sensor technology was used with the SkinChip device.

RESULTS

The non-optical images obtained by this means clearly identified low capacitance comedones contrasting with a perifollicular rim of high capacitance in inflammatory papules. This method also showed sweating and the follicular pores distributed in a pinpoint pattern.

CONCLUSION

The objective mapping of skin surface capacitance showed large differences between acne lesions and the surrounding skin. The low capacitance of comedones contrasted with the high capacitance of the perifollicular area in inflammatory papules. These electrometric characteristics reflecting the corneocyte hydration may influence drug affinity to acne lesions.

Moisturizing effect of cosmetic formulations containing Aloe vera extract in different concentrations assessed by skin bioengineering techniques

BACKGROUND/PURPOSE

The polysaccharide-rich composition of Aloe vera extracts (Aloe barbadensis Miller), often used in cosmetic formulations, may impart moisturizing properties to the product. The aim of this study was to evaluate the effect of cosmetic formulations containing different concentrations of freeze-dried Aloe vera extract on skin hydration, after a single and a 1- and 2-week period of application, by using skin bioengineering techniques.

METHODS

Stable formulations containing 5% (w/w) of a trilaureth-4 phosphate-based blend were supplemented with 0.10%, 0.25% or 0.50% (w/w) of freeze-dried Aloe vera extract and applied to the volar forearm of 20 female subjects. Skin conditions in terms of the water content of the stratum corneum and of transepidermal water loss (TEWL) (Corneometer CM 825 and Tewameter TM 210) were analysed before and after a single and 1- and 2-week period of daily application.

RESULTS

After a single application, only formulations supplemented with 0.25% and 0.50% (w/w) of Aloe vera extract increased the water content of the stratum corneum, while after the 2-week period application, all formulations containing the extract (0.10%, 0.25% and 0.50%) had the same effect, in both cases as compared with the vehicle. TEWL was not modified after a single and after 1- and 2-week period of application, when compared with the vehicle.

CONCLUSION

Our results show that freeze-dried Aloe vera extract is a natural effective ingredient for improving skin hydration, possibly through a humectant mechanism. Consequently, it may be used in moisturizing cosmetic formulations and also as a complement in the treatment of dry skin.

Instrumental assessment of atopic eczema: Validation of transepidermal water loss, stratum corneum hydration, erythema, scaling, and edema

BACKGROUND

Quantification of skin diseases can be carried out in many ways. Clinical scores are widely used in atopic eczema (AE), and noninvasive instruments are a relevant supplement.

OBJECTIVE

Our purpose was to validate 5 noninvasive instruments in quantification of AE severity.

METHODS

In all, 101 patients with AE and 30 control subjects were assessed twice in a clinical cross-sectional examination. Assessment of transepidermal water loss, stratum corneum hydration, erythema, scaling, and subepidermal edema was assessed on 3 predetermined skin sites.

RESULTS

The methods discriminated among various severity degrees and correlated significantly with objective assessment of disease severity. High correlations were found among instruments assessing acute symptoms of AE. Threshold values for transepidermal water loss and capacitance were found.

LIMITATIONS

No gold standard exists for severity assessment of atopic eczema. Therefore, the methods used cannot be validated in relation to such a standard. Furthermore, atopic eczema is a generalized disease and the methods used assess target lesions. By assessing target lesions, information about the disease is reduced.

CONCLUSION

Noninvasive instruments are valuable in quantification of disease severity in a mixed group of patients with active AE. Assessment with ultrasound has contributed new information about the pathophysiology in AE.

Skin capacitance mapping of psoriasis

BACKGROUND

The pathobiological dynamics of psoriatic lesions are complex and difficult to perceive by clinical inspection alone. Non-invasive bioengineering methods may prove to be useful in this field.

OBJECTIVE

To identify some subtle capacitance variations in the stratum corneum of chronic psoriasis lesions.

METHOD

The newly developed method of skin capacitance imaging was used to provide non-optical images of the hydration of the superficial layers of the stratum corneum.

RESULTS

Compared to the uninvolved skin, psoriatic lesions usually showed an overall lowered capacitance, admixed with foci of moderately higher capacitance. Still other sharply circumscribed blotches with higher capacitance were present. The latter aspect corresponded to inflammatory areas. Sweating appeared markedly impaired inside the lesions. The fingerprint of some patients was altered, thus potentially interfering with the current biometric security procedures using the same method.

CONCLUSION

Skin capacitance imaging is a non-invasive, non-optical method that distinguishes three contrasting levels of stratum corneum hydration in psoriatic lesions. The lowest capacitance level probably corresponded to xerotic orthokeratosis. The medium capacitance level presumably identified foci of parakeratosis and clumps of neutrophils. The highest capacitance level suggested exsudation at the site of prominent vessel dilation and dermal inflammation. Impaired sweating in the psoriatic lesions may potentially interfere with body thermoregulation.

Characterization strategies for the functional assessment of the cutaneous lesion

Assessment of wound healing is a complex task, especially when the lesion is associated to significant (full thickness) loss of the skin. The clinical observation, essentially subjective and highly dependent on the observer's experience, creates difficulties in the comparison of results. Scoring scales were introduced in the clinical practice to create comparable semi-quantitative data and promote better management of resources, but its usefulness in a clinical perspective is still limited. New non-invasive biometric methodologies, although infrequently used, have opened new possibilities. While complementing the clinical observation and contributing to therapeutic decisions and prognosis, they may also help to look further into the pathophysiological mechanisms of scarring drugs rehabilitation. Following previous work in this arena, the authors review, the state-of-the-art of cutaneous wound healing clinical and biometric follow up, proposing a diagnosis correlation for the most relevant descriptors found in both strategies in order to fully characterise the different stages of the healing process.

Anti-irritants I: dose–response in acute irritation

The term 'anti-irritant' (AI) was coined in 1965 by Goldemberg to describe a diverse group of topical product ingredients, which were able to reduce the irritation potential of other more irritating ingredients in the same product. 'AIs' are being added to cosmetic formulations in order, allegedly, to benefit tolerability of the products and allow claims such as 'soothing' and 'healing' ingredients. Limited documentation in favour of the efficacy of AIs is published. We studied the dose-related effect of 4 alleged AIs (nifedipine, (-)-alpha-bisabolol, canola oil and glycerol) on experimentally induced acute irritation in healthy volunteers. Each AI was used in 3 concentrations. Acute irritation was induced by occlusive tests with 1% sodium lauryl sulfate and 20% nonanoic acid in N-propanol. The irritant reactions were treated twice daily with AI-containing formulations from the time of removal of the patches. Evaluation of skin irritation and efficacy of treatments were performed daily for 4 days using clinical scoring, evaporimetry (transepidermal water loss), hydration measurement and colourimetry. Only glycerol showed dose-response and effects potentially better than no treatment. There was no significant effect and no difference between the three other AIs.

Anti-irritants II: efficacy against cumulative irritation

So-called anti-irritants (AI) are widely used in cosmetic formulations, with the aim of reducing irritation from substances in the formulation. It may also be claimed that they are 'soothing' and 'healing' ingredients. However, the proof for these claims is circumstantial. The dose-response effect of 4 alleged AI (nifedipine, (-)-alpha-bisabolol, canola oil and glycerol) was studied on experimentally induced acute irritation in healthy volunteers, and only glycerol showed dose-related response and effects potentially better than no treatment. The acute irritation model only allowed a small window of opportunity in which to demonstrate efficacy. Therefore, the effect of AI was studied in a cumulative irritation model by inducing irritant dermatitis with 10 min daily exposures for 5+4 days (no irritation on weekend) to 1% sodium lauryl sulfate on the right and 20% nonanoic acid on the left volar forearm. AI ointments were applied twice daily. Clinical scoring was performed daily, evaporimetry (Trans Epidermal Water Loss), hydration and colourimetry were measured at baseline (D0), in the middle and at the end of treatment. The glycerol ointment was the only treatment statistically better than both 'no treatment' and vehicle.

The hairless guinea-pig as a model for treatment of acute irritation in humans

BACKGROUND

The effect of six skin care formulations on experimentally induced acute irritation was studied in hairless guinea-pigs (HLGP) and in human volunteers (HV). The formulations were a basic cream, a carbomer cream and four modifications of the carbomer cream, containing either 10% isopropyl palmitate (IPP cream), 10% glycerol (glycerol cream), 19.5% canola oil (canola oil cream) or 0.5% (-)-alpha-bisabolol (bisabolol cream).

METHODS

Acute irritation was induced by occlusive tests with 1% sodium lauryl sulfate aq. in both HLGP and HV, and in HV also by using nonanoic acid in n-propanol (NON) 20%. The irritant reactions were treated twice daily with the formulations from the time of removal of the patches. Evaluation of skin irritation and efficacy of treatments was performed daily for 4 days using clinical scoring, evaporimetry (transepidermal water loss), hydration measurement and colorimetry.

RESULTS

The glycerol cream was the only product showing effects potentially better than no treatment in HV.

CONCLUSION

The HLGP was too sensitive an animal model as a predictor for effect in humans. There was no difference in efficacy of the formulations against the two different irritants in HV.