Penetration rates into the stratum corneum layer: A novel quantitative indicator for assessing skin barrier function.

BACKGROUND: The stratum corneum (SC), the outermost layer of the skin epidermis, acts as an effective bi-directional barrier, preventing water loss (inside-outside barrier) and entry of foreign substances (outside-inside barrier). Although transepidermal water loss (TEWL) is a widely-used measure of barrier function, it represents only inside-outside protection. Therefore, we aimed to establish a non-invasive method for quantitative evaluation of the outside-inside barrier function and visually present a skin barrier model. MATERIALS AND METHODS: Skin barrier damage was induced by applying a closed patch of 1% sodium dodecyl sulfate to the forearms of eight participants; they were instructed to apply a barrier cream on a designated damaged area twice daily for 5 days. The SC barrier was evaluated by measuring TEWL and fluorescein sodium salt penetration rate before, immediately after, and 5 days after damage. The penetration rate was assessed using tape-stripping (TS) technique and fluorescence microscopy. RESULTS: The rates of fluorescein sodium salt penetration into the lower layers of SC differed significantly based on the degree of skin barrier damage. The correlation between penetration rate and TEWL was weak after two rounds of TS and became stronger after subsequent rounds. Five days after skin barrier damage, the penetration rate of all layers differed significantly between areas with and without the barrier cream application. CONCLUSION: Our findings demonstrated that the penetration rate was dependent on skin barrier conditions. The penetration rate and corresponding fluorescence images are suitable quantitative indicators that can visually represent skin barrier conditions.

A study of anti-wrinkle functions and improvement of cream with Phaseolus angularis.

Chronic exposure to ultraviolet (UV) radiation from sunlight accelerates skin ageing, which is followed by harsh, thick, dry and loose conditions. One of the most demonstrative symptoms is deep wrinkles induced by skin barrier disruption. Our previous research showed that Phaseolus angularis seed extract (PASE) effectively inhibits skin ageing through UVB protection in HaCaT cells by suppressing skin damage. However, its efficacy has not been evaluated in clinical trials so far. PASE cream's effectiveness was initially tested on the artificial skin model, revealing an increase in filaggrin and defence against skin damage. Based on these results, in this single-centred, randomized, double-blind study, we investigated the anti-ageing effect of PASE in human eye wrinkle areas. For these 21 healthy adult women aged 30 to 59, a PASE cream was applied to the right eye wrinkle area and a placebo to the left eye wrinkle area twice a day (morning and evening) for 12 weeks. The change in thick, deep crease wrinkles around the eyes was confirmed by visual evaluation, skin measurements and a questionnaire. As a result, the surface roughness (R1), maximum roughness (R2), average roughness (R3), smoothness depth (R4) and arithmetic mean roughness (R5) values in the group using the PASE cream all decreased. Particularly, R1, R4 and R5 significantly decreased by 18.1%, 18.6% and 25.0%, respectively. Subjects who applied PASE cream also experienced an improvement in skin moisture nearly twice the time compared to the placebo group. In addition, no participants reported side effects. Our study showed that PASE cream led to clinically significant levels of wrinkle improvement. In conclusion, as PASE is a natural, safe food with no side effects, it can be a good resource for natural anti-wrinkle functional cosmetics in the future.

L'exposition chronique aux rayons ultraviolets (UV) du soleil accélère le vieillissement cutané, qui provoque un épaississement et un assèchement de la peau et la rend plus lâche. La présence de rides profondes induites par la rupture de la barrière cutanée en constitue l'un des symptômes les plus manifestes. Lors d'études précédentes, nous nous sommes rendu compte que l'extrait de graines de Phaseolus angularis (PASE) inhibait efficacement le vieillissement de la peau en assurant la protection anti­UVB des cellules HaCaT grâce à la suppression des lésions cutanées. Cependant, son efficacité n'a pas été évaluée lors d'essais cliniques à ce jour. L'efficacité de la crème PASE a d'abord été testée sur le modèle de peau artificielle, sur laquelle elle a fait augmenter les taux de filaggrine et assuré une défense contre les lésions cutanées. Sur la base de ces résultats, dans cette étude unicentrique, randomisée et en double aveugle, nous avons étudié l'effet anti­âge de la PASE chez l'humain au niveau des rides proches de l'œil. Pour ces 21 femmes adultes en bonne santé âgées de 30 à 59 ans, une crème PASE a été appliquée sur la zone de rides de l'œil droit et un placebo sur la zone de rides de l'œil gauche deux fois par jour (matin et soir) pendant 12 semaines. La modification des rides profondes et épaisses autour des yeux a été confirmée par une évaluation visuelle, des mesures cutanées et un questionnaire. Il a été découvert que les valeurs de rugosité de surface (R1), de rugosité maximale (R2), de rugosité moyenne (R3), de profondeur de douceur (R4) et de moyenne arithmétique (R5) dans le groupe à l'aide de la crème PASE avaient toutes diminué. En particulier, R1, R4 et R5 ont significativement diminué de 18,1 %, de 18,6 % et de 25,0 %, respectivement. Les patients qui ont appliqué la crème PASE ont également présenté une amélioration de l'hydratation de la peau presque deux fois supérieure à celle du groupe placebo. En outre, aucun participant n'a signalé d'effets secondaires. Notre étude a montré que la crème PASE entraînait des niveaux cliniquement significatifs d'amélioration des rides. En conclusion, comme le PASE est un aliment naturel, sûr et dépourvu d'effets secondaires, elle peut constituer une bonne ressource pour les cosmétiques fonctionnels naturels antirides à l'avenir.

Probing the effectiveness of barrier creams against human skin penetration of nickel powder.

OBJECTIVE: Barrier creams (BCs) are marketed as locally applied medical devices or cosmetic products to protect the skin from exposure to chemicals and irritants. Generally, the mechanism of action of such products is mainly due to the formation of a superficial thin film between the skin and the irritant or sensitizer, thus reducing or totally blocking the cutaneous penetration of such agents. Specifically, studies focusing on the effectiveness of commercial protective creams to prevent nickel cutaneous penetration are extremely scarce. The aim of the current work, therefore, is to evaluate the protective role of a commercially available barrier cream for nickel and compare the results with a simple moisturizing, following exposure to Ni powder. METHODS: Marketed BCs were evaluated and tested. Human skin absorption of Ni was studied in vitro using static Franz diffusion cells. RESULTS: Our results demonstrate that the application of both formulations caused a reduction of Ni inside the skin (8.00 ± 3.35 µg cm-2 for the barrier cream and 22.6 ± 12.6 µg cm-2 for the general moisturizing product), with the specialized barrier cream being statistically (p = 0.015) more efficient on forming a protective barrier, thus evidencing the importance of some ingredients in such formulations on the nickel dermal accumulation. CONCLUSIONS: The composition of the formulations based on film-forming or chelating agents may play an imperative role in reducing the cutaneous penetration of Ni.

OBJECTIF: Les crèmes de barrière (CB) sont commercialisées en tant que dispositifs médicaux ou produits cosmétiques appliqués localement pour protéger la peau contre l'exposition aux produits chimiques et irritants. En général, le mécanisme d'action de ces produits est principalement dû à la formation d'un film mince superficiel entre la peau et l'irritant ou le sensibilisant, réduisant ainsi ou bloquant totalement la pénétration cutanée de ces agents. Plus précisément, les études portant sur l'efficacité des crèmes protectrices commercialisées pour prévenir la pénétration cutanée du nickel sont extrêmement rares. L'objectif du projet en cours est donc d'évaluer le rôle protecteur d'une crème barrière disponible dans le commerce contre le nickel et de comparer les résultats à un simple hydratant après une exposition à la poudre de Ni. MÉTHODES: Des CB commercialisées ont été évaluées et testées. L'absorption cutanée du Ni dans la peau humaine a été étudiée in vitro à l'aide de cellules de diffusion statiques de Franz. RÉSULTATS: Nos résultats démontrent que l'application des deux formulations a entraîné une réduction du taux de Ni à l'intérieur de la peau (8,00 ± 3,35 µg·cm-2 pour la crème barrière et 22,6 ± 12,6 µg·cm-2 pour le produit hydratant ordinaire), la crème barrière spécialisée étant statistiquement (p = 0,015) plus efficace pour former une barrière protectrice, démontrant ainsi l'importance de certains ingrédients dans ces formulations sur l'accumulation dermique du nickel. CONCLUSIONS: La composition des formulations basées sur des agents de formation de film ou de chélation peut jouer un rôle nécessaire pour réduire la pénétration cutanée du Ni.

Skin-Microbiome Assembly in Preterm Infants during the First Three Weeks of Life and Impact of Topical Coconut Oil Application.

The structure and function of infant skin is not fully developed until 34 weeks of gestation, and this immaturity is associated with risk of late-onset sepsis (LOS). Topical coconut oil improves preterm-infant skin integrity and may reduce LOS. However, data on early-life skin-microbiome succession and potential effects of emollient skin care in preterm infants are scarce. We therefore collected skin-microbiome samples from the ear, axilla, and groin on days 1, 7, 14, and 21 from preterm infants born <30 weeks of gestation as part of a randomized clinical trial of standard skin care vs. topical coconut oil. We found that within-sample microbiome diversity was highest on day 1 after birth, with a subsequent decline and emergence of Staphylococcus genus dominance from day 7. Moreover, microbiome assembly was less diverse in infants receiving coconut oil vs. standard skin care. Our study provides novel data on preterm-infant skin-microbiome composition and highlights the modifying potential of emollient skin care.

Effects of a lotion containing probiotic ferment lysate as the main functional ingredient on enhancing skin barrier: a randomized, self-control study.

There is an emergent need to develop functional cosmetic ingredients for the topical management of skin barrier function. This study aimed to investigate the efficacy of a lotion containing fermented lysates VHProbi® Mix R for enhancing the skin barrier. In vitro studies demonstrated that fermented cultures of both Lacticaseibacillus rhamnosus VHProbi® E06 (E06) and L. paracasei VHProbi® E12 (E12) had antioxidant capacity, showing promising scavenging capability for 2,2-diphenyl-1-picryl-hydrazyl. The antioxidant capacity of these strains was also demonstrated in the model of Caenorhabditis elegans. In addition, the fermented lysates of both E06 and E12 enhanced the proliferation of HaCaT cells and ameliorated the toxicity induced by Staphylococcus aureus ATCC 25923, hydrogen peroxide, and ultraviolet B radiation in the HaCaT cell models, which simulated the irritants that facial sensitive skin is exposed to. Subsequently, the ingredient VHProbi® Mix R was formulated using four kinds of fermented lysates: E06, E12, Lactiplantibacillus plantarum VHProbi® E15, and Lactobacillus helveticus VHProbi® Y21. A clinical study was conducted to investigate whether a lotion containing VHProbi® Mix R would be beneficial for people to enhance skin barrier. The participants were asked to use the investigational product for 30 days. Several indicators, including transepidermal water loss (TEWL), skin moisturization, and redness were measured at day 0 and day 30 using VISIA®-CR and CK®-MPA systems. Meanwhile, the burden of sensitive skin (BoSS) and self-assessment questionnaires were performed at baseline and endpoint of this study. The study data showed that at day 30, there was a significant decrease in TEWL (P < 0.01), redness measured by CK®-MPA (P < 0.01), and redness profile measured by VISIA®-CR compared with the baseline measurements. Skin moisturization had significantly increased after treatment with the lotion for 30 days. BoSS and self-assessment questionnaires also substantiated that the participants felt a markedly positive change in their sensitive skin. Hence, we hypothesize that applying the topical functional VHProbi® Mix R could confer effective benefits for people with sensitive skin and this represents a promising intervention for enhancing skin barrier.

Topical Cream Derived From Hylocereus polyrhizus (Red Dragon Fruit) Extract Accelerates Wound Healing Through Increased Hydroxyproline and Fibroblast Growth Factor 2 Levels: A Pilot Study.

The red dragon fruit (Hylocereus polyrhizus) extract (RDFE) is frequently used for a variety of therapeutic purposes (e.g., boosting the immune system, promoting a healthy gastrointestinal system, improving wound healing). We investigated the effects of a topical cream containing 7.5% RDFE on hydroxyproline and fibroblast growth factor 2 (FGF-2) levels and wound healing. On Day 0, we divided a total of 36 albino male Wistar rats into two equal groups. Using an 8-mm punch biopsy, we created a circular excision to fascial depth on the back of each rat. On Day 1, we treated the control group (n = 18) with 20 mg of base cream and the RDFE group (n = 18) with 20 mg of 7.5% RDFE cream. We measured hydroxyproline and FGF-2 levels in the wound tissue using an ELISA method on Days 3, 7, and 14. We found that on Day 3, hydroxyproline levels were significantly lower in the treatment group than in the control group (p = .031). We also found a significant correlation between FGF-2 levels in the treatment group and wound diameter (p = .02). On the basis of the results of this study, we concluded that using a topical cream containing 7.5% RDFE has the potential to accelerate wound healing by increasing levels of hydroxyproline and FGF-2 in the wound.

Ceramide AD™ Restores Skin Integrity and Function following Exposure to House Dust Mite.

Ceramides are epidermal lipids important for normal skin barrier function. Reduced Ceramide content is associated with atopic dermatitis (AD). House dust mite (HDM) has been localized in AD skin where it plays an exacerbator role. We set to examine the impact of HDM on skin integrity and the effect of three separate Ceramides (AD™, DS, Y30) on HDM-induced cutaneous damage. The effect was tested in vitro on primary human keratinocytes and ex vivo on skin explants. HDM (100 µg/mL) decreased the expression of adhesion protein E-cadherin, supra-basal (K1, K10) and basal (K5, K14) keratins and increased matrix metallopeptidase (MMP)-9 activity. The presence of Ceramide AD™ in topical cream inhibited HDM-induced E-cadherin and keratin destruction and dampened MMP-9 activity ex vivo which was not seen for the control cream or cream containing DS or Y30 Ceramides. The efficacy of Ceramide AD™ was tested in a clinical setting on moderate to very dry skin (as surrogate for environment-induced skin damage). When applied topically for 21 days, Ceramide AD™ significantly reduced transepidermal water loss (TEWL) in patients with very dry skin compared to their TEWL baseline data. Our study demonstrates Ceramide AD™ cream to be effective in restoring skin homeostasis and barrier function in damaged skin and warrants testing in larger clinical trials for possible treatment of AD and xerosis.

Evaluation of a Novel Skin Emollient Cream on Skin Lipidome and Lipid Organization.

INTRODUCTION: The stratum corneum (SC) matrix is composed of free fatty acids, cholesterol, and ceramides (CERs), which play a key role in the skin barrier function. Changes in the composition and content of skin lipids will affect the function of the skin barrier. The effect of a glycerol/petrolatum-based emollient (G/P-emollient) cream on the lipid profiles of isolated ex vivo human SC and the SC of a reconstructed human epidermis (RHE) model was measured. METHODS: The spatial organization of the cream and the isolated SC intercellular matrix were studied using X-ray diffraction. The inter-bilayer distances in the multi-lamellar lipid structures and lattice type were analyzed using small-angle X-ray scattering and wide-angle X-ray scattering (WAXS), respectively. Lipidomic analysis using shotgun lipidomics was performed on RHE models to quantify CER classes and chain lengths. This technology enables the analysis of thousands of lipids in a single biological sample. RESULTS: The crystallized components of the cream are lipids, which were mainly packed in orthorhombic lattices, as well as hexagonal lattices and were similar to the SC structure. The cream penetrated the SC but did not alter the WAXS profile. It increased the amount of higher carbon number CERs (>42 carbons) and decreased lower carbon number CERs (<42 carbons). All chain length of CERs and acyl-CER classes (CER EOS, EOH, EOP, EOdS) were increased as the total CER classes. A decrease of the CER C34 for hydroxylated and non-hydroxylated CERs was also observed. The cream altered the S and P CER forms (increased the NP/NS and AP/AS ratios), indicating it could reduce the relative feedback mechanism observed in inflammatory pathologies, for example, atopic dermatitis. The cream increased CER NP, which is decreased in dry skin. CONCLUSION: G/P-emollient cream may be beneficial for skin pathologies by modifying SC lipids, balancing CER levels and ratios, and improving the barrier function. Importantly, the cream structure mimics that of the SC and penetrated the lower SC layers without compromising its lamellar structure.

Impact of defensins-containing body cream on skin composition.

BACKGROUND AND AIMS: Defensins are peptides capable of reactivating latent LGR6 stem cells in the basal layer. When applied topically, these peptides can reduce signs of skin aging and increase dermal thickness. This study investigates the effects of a topical defensin formulation on extremity skin composition. METHODS: An open label, single arm clinical trial was conducted on participants with dry, photoaged, or dull skin. A defensin-containing hand and body cream was applied twice daily for 6 weeks to the hands, forearms, elbows, and knees. Photographs and objective measurements of skin hydration, viscoelasticity (VE), retraction time (RT), thickness, density/transepidermal water loss (TEWL), as well as self-evaluation of skin quality and characteristics were obtained pre- and post- intervention. RESULTS: After the study period, RT decreased by 56% across all body sites (p < 0.001) and VE improved at the elbow (125%, p = 0.009) and knee (110%, p < 0.001). Skin density also increased in all 4 body sites (40%, p < 0.001), while skin thickness increased at the elbow (29%, p = 0.03) and knee (17%, p = 0.04). Skin hydration increased at the elbow, knee, and forearm by 99%, 28%, and 16%, respectively (p < 0.05), while TEWL improved at the elbow only (-39%, p = 0.02). Patients' self-evaluations showed improvements in overall skin quality and in the domains of dryness, ashiness, wrinkling, pigmentation, redness, roughness, and discomfort (p < 0.05). CONCLUSIONS: Following 6-week use of a defensin-containing cream, subjects reported significant improvement across many subjective skin domains. Similarly, objective measurements demonstrated significant improvement in skin architecture at select sites.

2-kDa hyaluronan ameliorates human facial wrinkles through increased dermal collagen density related to promotion of collagen remodeling.

BACKGROUND/AIMS: Hyaluronan (HA) oligosaccharides are involved in several biological processes, primarily collagen remodeling and wound healing. Collagen remodeling is retarded in aging skin and causes wrinkles. The aim of this study was to evaluate the effect of 2-kDa HA oligosaccharides (HA2k) on wrinkles by permeation through the stratum corneum and promotion of collagen remodeling. METHODS: A 3D skin model and excised human skin were used to evaluate the permeation of fluorescein-labeled HA2k. The effect of HA2k on collagen metabolism was evaluated by measuring the protein level of type 1 pro-collagen (COL1A1) and matrix metalloproteinase-1 (MMP-1) in the 3D skin model. 0.1% HA2k solution and vehicle control was applied to the human forearm for 8 weeks to evaluate dermal collagen density. To evaluate the effect of HA2k on depth of facial wrinkles, a randomized controlled trial was conducted with 0.1% HA2k lotion and vehicle lotion for 8 weeks. RESULTS: HA2k was confirmed to permeate through the stratum corneum by fluorescent microscopy. Both COL1A1 and MMP-1 were upregulated by HA2k application in a 3D skin model culture. The collagen density was higher for the HA2k-treated forearm than for the vehicle control-treated forearm after 4 weeks. The maximum wrinkle depths in the nasolabial fold and crow's feet area were significantly shallower in the HA2k lotion group than in the control group. CONCLUSION: HA2k permeated the stratum corneum, activated collagen synthesis and degradation simultaneously, and ameliorated wrinkles.

The Moisturizing Efficacy of a Proprietary Dermo-Cosmetic Product( CLS02021) Versus Placebo in a 4-week Application Period.

Background: Studies suggest that applying probiotic skincare products may have beneficial effects on the skin due to bacteria competitiveness and specific metabolites produced by probiotics. The cream CLS02021 is a postbiotic blend of metabolites, including organic acids, enzymes, and peptides that are a result of the co-fermentation of three proprietary probiotic strains and is specific for its high concentration of the enzyme Sphingomyelinase which plays a significant role in cell signaling pathways and ceramide production. Objective: The aim of this study is to evaluate the cosmetic effects of probiotic-derived Ingredient CLS02021 and its safety in healthy volunteers. Methods: Fifty healthy volunteers between 18 and 69 years old were recruited to participate in this multicentric, randomized, intra-individual, double-blind group study. Following a face-split design, volunteers applied both face cream containing CLS02021 on one side of their face and a placebo cream on the other side of their face for a total duration of four weeks, two times a day. Evaluation of the cosmetic effects included instrument measurements of moisturizing, elasticity, wrinkle depth, sebum production, pore size, melanin production, sensitivity, and side effects. Results: A significant difference of CLS02021 over the placebo group was observed for moisture and elasticity increase (both p<0.001), pore size (p<0.01), and a wrinkle depth decrease (p<0.05). No significant differences were noted in sebum production, melanin level, skin cleanliness, and sensitivity between groups. Conclusion: CLS02021, as a probiotic-derived ingredient, showed strong beneficial effects on skin moisture and elasticity increase, wrinkle depth, and pore size reduction. Face cream containing CLS02021 is well tolerated and could be an organic choice for cosmetic hydrating and antiaging skincare treatment.

From decoding the perception of tightness to a clinical proof of soothing effects derived from natural ingredients in a moisturizer.

OBJECTIVE: To decode the feeling of skin tightness after application of a cosmetic product and how to soothe this discomfort. To pursue this aim, we considered the ingredient's effect on stratum corneum (SC) biomechanics to differentiate between consumers prone to tightness from those that are not and correlate these effects with mechanoreceptor activation. METHODS: In vivo clinical trials were used to assess the tightness perception dichotomy between groups of Caucasian women; in vitro experiments were used to measure the mechanical stresses induced in the SC after cleanser and moisturizer application; and in silico simulations were used to illustrate how the measured mechanical stresses in the SC result in the development of strains at the depth of cutaneous mechanoreceptors, triggering tightness perceptual responses. RESULTS: Before any cream application, women prone to tightness tend to have a more rigid SC than their less sensitive counterparts, however cleanser application increases SC stiffness in all women. Surprisingly, no correlation was found between tightness perception and hydration measurements by the Corneometer or barrier function, as evaluated by transepidermal water loss. Self-declared tightness and dryness scores were strongly associated with a self-described sensitive skin. After application of the optimized moisturizing formula, Osmoskin® containing natural waxes with good filming properties, consumers report a strong decrease in tightness and dryness perception. These results match with laboratory experiments where the cleanser was shown to increase SC drying stresses by 34%, while subsequent application of Osmoskin® decreased stresses by 48%. Finite element modelling, using experimental results as input, elucidates the differences in perception between the two groups of women. It makes clear that Osmoskin® changes the mechanical status of the SC, producing strains in underlying epidermis that activates multiple cutaneous mechano-receptors at a level correlated with the self-perceived comfort. CONCLUSION: Integration of the in vivo, in vitro and in silico approaches provides a novel framework for fully understanding how skin tightness sensations form and propagate, and how these sensations can be alleviated through the design of an optimized moisturizer.

OBJECTIF: Décoder l'impression de tiraillement de la peau après l'application d'un produit cosmétique et la manière d'apaiser cette sensation désagréable. Pour poursuivre cet objectif, nous avons pris en compte l'effet de l'ingrédient sur la biomécanique de la couche cornée afin de différencier les consommatrices sujettes à un tiraillement de celles qui ne le sont pas et de corréler ces effets avec l'activation des mécanorécepteurs. MÉTHODES: Des essais cliniques in vivo ont été utilisés pour évaluer la dichotomie de perception de tiraillement entre des groupes de femmes de race caucasienne; des expériences in vitro ont été utilisées pour mesurer les contraintes mécaniques induites dans la couche cornée après application d'un produit nettoyant et d'un produit hydratant; et des simulations in silico ont servi à illustrer comment les contraintes mécaniques mesurées dans la couche cornée entraînent le développement de souches à la profondeur des mécanorécepteurs cutanés, qui déclenchent les réponses perceptives de tiraillement. RÉSULTATS: Avant toute application de crème, les femmes sujettes au tiraillement tendent à avoir une couche cornée plus rigide que leurs homologues moins sensibles, mais l'application d'un produit nettoyant augmente la raideur de la couche cornée chez toutes les femmes. Étonnamment, aucune corrélation n'a été observée entre la perception de tiraillement et les mesures d'hydratation réalisées par le cornéomètre ou la fonction barrière, évaluée par la perte d'eau transépidermique. Les scores de tiraillement et de sécheresse auto-déclarés étaient fortement corrélés à une peau décrite par les sujets elles-mêmes comme sensible. Après application de la formule hydratante optimisée, Osmoskin®, qui contient des cires naturelles ayant de bonnes propriétés de dépôt de film, les consommateurs rapportent une forte diminution de la sensation de tiraillement et de sécheresse. Ces résultats concordent avec les expériences en laboratoire où le produit nettoyant s'est avéré augmenter les contraintes de séchage de la couche cornée de 34 %, tandis que l'application ultérieure d'Osmoskin® a réduit les contraintes de 48 %. La modélisation à éléments finis, en utilisant les résultats expérimentaux comme données, élucide les différences de perception entre les deux groupes de femmes. Il est clair qu'Osmoskin® modifie l'état mécanique de la couche cornée, et produit des souches dans l'épiderme sous-jacent qui activent plusieurs mécano-récepteurs cutanés à un niveau corrélé au confort perçu par la patiente. CONCLUSION: La combinaison des approches in vivo, in vitro et in silico fournit un nouveau cadre pour comprendre pleinement comment les sensations de tiraillement de la peau se forment et se propagent, et comment elles peuvent être soulagées en mettant au point une crème hydratante optimisée.

The Effect of Sun Tan Lotion on Skin by Using Skin TEWL and Skin Water Content Measurements.

Stratum corneum (SC) is the outermost skin layer. SC hydration is important for its cosmetic properties and barrier function. SC trans-epidermal water loss (TEWL) measurements and skin water content measurements are two key indexes used for SC characterisation. The instrument stability and accuracy are vitally important when measuring small changes. In this paper, we present our latest study on the effect of sun tan lotion on skin by using skin TEWL and skin water content measurements. We developed techniques to improve the measurement stability and to visualise small changes, as well as developed machine learning algorithms for processing the skin capacitive images. The overall results show that TEWL and skin water content measurements are capable of measuring the subtle changes of skin conditions due to the application of sun tan lotions. The results show that the TEWL values decreased after the sun tan lotion application. The sun tan lotion with SPF 20 had the lowest decrease, whilst the sun tan lotion with SPF 50+ had the highest decrease. The results also show that the skin water content increased after the sun tan lotion application, with SPF 20 having the highest increase, whilst SPF 50+ had the lowest increase.

Efficacy of a fine fiber film applied with a water-based lotion to improve dry skin.

BACKGROUND: Dry skin can trigger eczema that affects >10% of the US population. Dressing films have been developed to improve diseased skin, but there is limited knowledge about their effects, especially for dry skin-related symptoms. We developed an electrospinning method that creates a coating film, called a fine fiber (FF) film, characterized by the production of a transparent, thin, flexible, and adherent membrane on the skin surface. OBJECTIVE: The aim of this pilot study was to examine the effects of the FF film on dry skin. METHODS: Three treatments (lotion only, lotion with the FF film, and lotion with an alternative film) were designed to treat subjects with rough skin on their lower legs. Twenty-four females were enrolled and used either a water-based lotion U or a petrolatum-based lotion P and the FF film for 2 weeks followed by a regression phase for 1 week. Skin hydration and roughness scores were assessed as were the subjects' perceptions of the effects. RESULTS: When the FF film was applied with lotion U, skin hydration was significantly improved even after 1 week, accompanied by a significant improvement of skin roughness and an increase in skin hydration by the end of the regression phase. An evaluation of moisture permeability suggested that the FF film, especially with lotion U, performed as a semipermeable membrane with optimal moisture healing effects on dry skin. CONCLUSION: The FF film together with a water-based lotion is a promising treatment to quickly improve dry skin conditions.

Specific protection of sensitive skin against environmental stress by maintenance and improvement of barrier function.

BACKGROUND: Sensitive skin is a common condition that can severely impact quality of life. Several mechanisms are thought to be involved, including those affecting the skin barrier function, hydration and skin innervation. OBJECTIVES: To investigate the benefit of cream and balm formulations dedicated to sensitive skin and containing Aquaphilus dolomiae extract-G3 (ADE-G3) on skin barrier functions (lipid composition, pH, TEWL), as well as protective responses to dry and pollution stresses. METHODS: In vitro sensitized (using histamine) reconstructed human epidermis (RHE) were subjected to dehydration and pollution stress in the absence and presence of the formulations. Endpoint measurements included transepithelial electric resistance (TEER), stratum corneum protein expression and lipid contents. Clinical measurements included transepithelial water loss (TEWL), skin pH and the lipid index. RESULTS: When applied in cream and balm formulations, ADE-G3, increased the TEER in sensitized RHEs. In non-sensitized dehydrated RHEs, both formulations increased recovery of skin barrier integrity after dehydration, evident as a return of the ratios of filaggrin/profilaggrin and caspase-14/procaspase-14 to values measured in control non-stressed RHEs, as well as reducing the 'natural moisturizing factor' to control levels. In clinical studies performed on dry human skin, the formulations helped to maintain and improve the skin barrier function. This was evident as an intense and sustained moisturization (total lipids and lipid esters were increased), an increase in pH and a decrease in the TEWL by both formulations. When exposed to pollution stress by treating the models with benzo[a]pyrene and airborne particulate matter (PM10), application of both formulations prior to exposure attenuated the induction of CYP1A1, CYP1B1 and UGT1A7 expression, indicating a protective effect. CONCLUSIONS: ADE-G3 cream and balm formulations increased the hydration of the skin but also protected and improved the skin barrier integrity of sensitive skin exposed to dry and cold and airborne pollutant-induced stress environments.

Skin occlusive performance: Sustainable alternatives for petrolatum in skincare formulations.

BACKGROUND: The emollients are important ingredients used in skincare formulations that can act as moisturizing agents through their occlusive potential, preventing skin water loss. Consumer interest in natural and sustainable products has grown considerably in the last few years, requiring efforts from the cosmetic industry to design products with raw materials of natural, organic, and sustainable origin. Thus, it is essential to improve the knowledge about the behavior of cosmetic raw materials that can be used as sustainable alternatives to synthetic ingredients. AIM: This work aimed to evaluate the occlusive performance of different vegetable oils used as emollients in skincare cosmetics, through comparative analysis with petrolatum, a synthetic emollient with a high occlusive skin potential. METHOD: The study included 80 healthy female adult volunteers. TEWL measurements were performed before and after 15 min, 2 and 6 h of emollients application on the forearms of the research participants. All research participants provided written informed consent. RESULTS: The results obtained showed that the vegetable oils were effective in providing an occlusive effect on the skin. When compared to the petrolatum, the vegetable oils did not provide a high immediate skin occlusion effect. However, most of them showed a skin occlusion performance comparable to petrolatum throughout the 6 h time course. CONCLUSION: Vegetable oils can be used as a sustainable alternative to synthetic emollients, and they are promising in replacing petrolatum in skincare formulations with respect to the occlusion effect of the skin. The vegetable oils did not provide a high immediate skin occlusion effect (15 min post-application) as the petrolatum, which is known to have increased occlusion properties. However, most of them showed a skin occlusion performance comparable to petrolatum throughout the 6-hour time course.

Formulation of an antibacterial topical cream containing bioengineered honey that generates reactive oxygen species.

SurgihoneyRO™ (SHRO) is a bioengineered medicinal honey proven to eradicate multi-drug resistant strains of bacteria by delivering a controlled dose of reactive oxygen species (ROS). The urgent need for novel antimicrobial therapies capable of tackling pathogens that have developed resitance to existing antimicrobial medicines, such as antibiotics, makes SHRO a highly desirable biomaterial. However, its application is currently limited in the medical field due to undesirable material properties. This study aims to formulate the honey into a clinically viable topical cream whilst maintaining antimicrobial efficacy. SHRO droplets were emulsified to protect the active until activation in-situ. Xanthan gum (XG) and fumed silica (FS) thickener systems were explored, with both formulations able to inhibit the growth of S. aureus in-vitro. However, FS formulations exhibited significantly higher hydrogen peroxide release over a period of 7 days and resulted in larger zones of inhibition (42%) than XG formulations. Selection of the optimum FS formulation was made based on evaluation of the material characteristics by means of rheology and texture analysis. In place of the sticky and highly viscous initial SHRO product, desirable material characteristics for a topical product were achieved, including thixotropic shear-thinning behaviour and significantly lower cohesiveness (15.3-22.4 N) than standard SHRO formulations (79.9 N). Furthermore, the product exhibited a low contact angle on porcine skin, indicating that these formulations would spread favourably on the skin surface, demonstrate a favourable sensory perception and be retained on the skin, making for a more clinically effective product. This work is the first report of an engineered cream system to controllably deliver ROS to a wound site and demonstrate its ability of eradicating clinically relevant bacteria in vitro.

Depth-dependent hydration dynamics in human skin: Vehicle-controlled efficacy assessment of a functional 10% urea plus NMF moisturizer by near-infrared confocal spectroscopic imaging (KOSIM IR) and capacitance method complemented by volunteer perception.

BACKGROUND: Stratum corneum (SC) hydration is vital for the optimal maintenance and appearance of healthy skin. In this context, we evaluated the efficacy of an NMF-enriched moisturizer containing 10% urea on different aspects of SC hydration of dry skin. MATERIAL AND METHODS: In two clinical studies, the hydration efficacy of the moisturizer in comparison to its vehicle was investigated. In the first study, 42 subjects applied the moisturizer and the vehicle to one lower leg each. Thirty minutes and 24 h after this single treatment, SC hydration was measured by corneometry. Volunteers also rated skin moisturization and evaluated product properties. In the second study, 27 subjects each treated one forearm twice daily for 2 weeks with the moisturizer and the vehicle. Then, depth-resolved water-absorption spectra were measured by near-infrared confocal spectroscopic imaging (KOSIM IR). RESULTS: The moisturizer exerted a superior hydrating effect compared to the vehicle. KOSIM IR measurements show that, compared to the vehicle, the moisturizer significantly improved the water gradient in the SC from the surface to a depth of 15 µm. Moreover, the moisturizer received high acceptance ratings from the volunteers and was preferred to the vehicle. CONCLUSION: The humectants applied in the investigated moisturizer improved SC water content in total and as a function of depth. The combination of depth-resolved data (KOSIM IR) with classical corneometry provides an integrated concept in the measurement of skin hydration, rendering both methods complementary. These findings were in line with the volunteers` self-assessments of the moisturizer properties that are relevant to treatment adherence.