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Skin Hydration (skin + hydration)
Selected AbstractsEffects of lipid nanocarriers on the performance of topical vehicles in vivoJOURNAL OF COSMETIC DERMATOLOGY, Issue 2 2009Mojgan Moddaresi PharmD Summary Background/aims, Nanocarrier systems have been extensively studied for their suitability in personal care formulations. Theoretically, they could enhance skin delivery of active compounds, thereby improving in vivo efficacy of the products. As such the aim of this study was to evaluate the effect of a lipid nanocarrier (LNC) system loaded with tocopheryl acetate (TA) on the hydration, biomechanical properties, and antioxidant capacity of human skin, when used in two different vehicles, and compare it with a non-LNC formulation. Methods, TA-loaded lipid nanocarriers (TA-LNCs) were produced by the phase inversion method, using physiological lipids and purified by ultra-centrifugation. They were incorporated into a hydrophilic gel and foam, and their performance compared with a saturated TA solution in silicon oil. Skin hydration and biomechanical properties were measured by means of a corneometer and a cutometer, respectively, while a high-resolution spectrophotometer was used to assess skin redness after stimulation by methyl nicotinate in a micro-inflammatory test. Both short-term (3 h) and long-term trials (4 weeks) were performed. Results, The results confirmed that the LNCs enhanced skin hydration in both studies, while skin viscoelastic parameters remained practically unchanged during the 4-week study. The antioxidant assessment failed to show significant difference between the test sites. Conclusions, TA-loaded LNCs exhibited the ability to enhance skin hydration, while their effect on skin biomechanical properties and on antioxidant efficacy could not be statistically proved. [source] Skin hydration: a review on its molecular mechanismsJOURNAL OF COSMETIC DERMATOLOGY, Issue 2 2007Sylvie Verdier-Sévrain MD Summary Water is absolutely essential for the normal functioning of the skin and especially its outer layer, the stratum corneum (SC). Loss of water from the skin must be carefully regulated, a function dependent on the complex nature of the SC. The retention of water in the SC is dependent on two major components: (1) the presence of natural hygroscopic agents within the corneocytes (collectively referred to as natural moisturizing factor) and (2) the SC intercellular lipids orderly arranged to form a barrier to transepidermal water loss (TEWL). The water content of the SC is necessary for proper SC maturation and skin desquamation. Increased TEWL impairs enzymatic functions required for normal desquamation resulting in the visible appearance of dry, flaky skin. There have been recent discoveries regarding the complex mechanisms of skin hydration. In particular, it has been discovered that glycerol, a well-known cosmetic ingredient, exists in the SC as a natural endogenous humectant. Hyaluronan, which has been regarded mainly as dermal component, is found in the epidermis and is important for maintaining normal SC structure and epidermal barrier function. More importantly, the discovery of the existence of the water-transporting protein aquaporin-3 in the viable epidermis and the presence of tight junction structures at the junction between the stratum granulosum and SC have brought new insights into the mechanisms of skin water distribution and barrier function. [source] Skin hydration and possible shunt route penetration in controlled estradiol delivery from ultradeformable and standard liposomesJOURNAL OF PHARMACY AND PHARMACOLOGY: AN INTERNATI ONAL JOURNAL OF PHARMACEUTICAL SCIENCE, Issue 10 2001Gamal M. M. El Maghraby Human skin delivery of estradiol from ultradeformable and traditional liposomes was explored, comparing occlusive and open application, with the aim of examining the role of skin hydration. Partially hydrated epidermis was used for open hydration, but fully hydrated membranes were used for occluded studies. In addition, we developed a novel technique to investigate the role of shunt route penetration in skin delivery of liposomal estradiol. This compared delivery through epidermis with that through a stratum corneum (SC)/epidermis sandwich from the same skin with the additional SC forming the top layer of the sandwich. This design was based on the fact that orifices of shunts only occupy 0.1% of skin surface area and thus for SC/epidermis sandwiches there will be a negligible chance for shunts to superimpose. The top SC thus blocks most shunts available on the bottom membrane. If shunts play a major role then the delivery through sandwiches should be much reduced compared with that through epidermis, taking into consideration the expected reduction owing to increased membrane thickness. After open application, both ultradeformable and traditional liposomes improved estradiol skin delivery, with the ultradeformable liposomes being superior. Occlusion reduced the delivering efficiency of both vesicle types, supporting the theory that a hydration gradient provides the driving force. Shunt route penetration was found to play only a very minor role in liposomal delivery. In conclusion, full hydration of skin reduces estradiol delivery from liposomes and the shunt route is not the main pathway for this delivery. [source] Skin hydration and transepidermal water loss in patients with a history of sulfur mustard contact: a case,control studyJOURNAL OF THE EUROPEAN ACADEMY OF DERMATOLOGY & VENEREOLOGY, Issue 8 2009Seyyed Masoud Davoudi Abstract Background,, Skin lesions are among the most common complications of contact with sulfur mustard. Objective,, This study was aimed to measure skin water content and transepidermal water loss (TEWL) in patients with a history of sulfur mustard contact. Methods,, Three hundred ten male participants were included in this study: 87 (28.1%) sulfur mustard,exposed patients with current skin lesions (group 1), 71 (22.9%) sulfur mustard,exposed patients without skin lesions (group 2), 78 (25.2%) patients with dermatitis (group 3) and 74 (23.8%) normal controls (group 4) The water content and TEWL of skin was measured at four different locations of the body: forehead, suprasternal, palm and dorsum of hand. Nonparametric statistical tests (Kruskal,Wallis) were used to compare the four groups, and P < 0.05 was considered statistically significant. Results,, The mean age of participants were 44.0 ± 6.7, 41.9 ± 5.9, 43.8 ± 9.3 and 44.8 ± 8.9 years in groups 1 to 4, respectively (P = 0.146). Xerosis, post-lesional hyperpigmentation and lichenification were significantly more common in either sulfur mustard,exposed participants or non-exposed participants with dermatitis (P < 0.05). Skin hydration was higher in subjects with sulfur mustard contact than in non-injured participants (P < 0.05) in the dorsum and palm of hands and forehead. TEWL was significantly higher in participants only in suprasternal area and dorsum of hand. Conclusion,, Contact with sulfur mustard agent can alter biophysical properties of the skin-especially the function of stratum corneum as a barrier to water loss-several years after exposure. Conflicts of interest None declared. [source] Cleansing without compromise: the impact of cleansers on the skin barrier and the technology of mild cleansingDERMATOLOGIC THERAPY, Issue 2004K. P. Ananthapadmanabhan ABSTRACT:, Cleanser technology has come a long way from merely cleansing to providing mildness and moisturizing benefits as well. It is known that harsh surfactants in cleansers can cause damage to skin proteins and lipids, leading to after-wash tightness, dryness, barrier damage, irritation, and even itch. In order for cleansers to provide skin-care benefits, they first must minimize surfactant damage to skin proteins and lipids. Secondly, they must deposit and deliver beneficial agents such as occlusives, skin lipids, and humectants under wash conditions to improve skin hydration, as well as mechanical and visual properties. While all surfactants tend to interact to some degree with lipids, their interaction with proteins can vary significantly, depending upon the nature of their functional head group. In vitro, ex vivo, and in vivo studies have shown that surfactants that cause significant skin irritation interact strongly with skin proteins. Based on this understanding, several surfactants and surfactant mixtures have been identified as "less irritating" mild surfactants because of their diminished interactions with skin proteins. Surfactants that interact minimally with both skin lipids and proteins are especially mild. Another factor that can aggravate surfactant-induced dryness and irritation is the pH of the cleanser. The present authors' recent studies demonstrate that high pH (pH 10) solutions, even in the absence of surfactants, can increase stratum corneum (SC) swelling and alter lipid rigidity, thereby suggesting that cleansers with neutral or acidic pH, close to SC-normal pH 5.5, may be potentially less damaging to the skin. Mildness enhancers and moisturizing agents such as lipids, occlusives, and humectants minimize damaging interactions between surfactants, and skin proteins and lipids, and thereby, reduce skin damage. In addition, these agents play an ameliorative role, replenishing the skin lipids lost during the wash period. The present review discusses the benefits of such agents and their respective roles in improving the overall health of the skin barrier. [source] Abstracts: The effects of licorice leaf extract on ceramide and hyaluronan synthesisINTERNATIONAL JOURNAL OF COSMETIC SCIENCE, Issue 5 2010Akinori Kiso pp.267,273 Both water-holding and permeability barrier function in the stratum corneum (SC) are essential for keeping skin moisture. Intercellular lipids in SC, which are composed mainly of cholesterol, fatty acids, and ceramides, play a crucial role for maintaining the function in SC. The object of our study is to find active ingredients from plant extracts for enhancing the abilities of skin hydration and barrier repair by focusing on the synthesis of ceramides. As a result, we found that licorice leaf extract is a promising ingredient showing not only an increase of mRNA expression levels of serine palmytoyltransferase (SPT) and sphingomyelinase related to ceramide biosynthesis in keratinocytes but also syntheses of ceramides in a 3D skin model and in human skin. Furthermore, licorice leaf extract showed an increase of mRNA expression levels of HMG-CoA reductase (HMGCR) related to cholesterol biosynthesis and an increase of hyaluronan (HA) production in in vitro tests. One of the principles isolated from licorice leaf extract, 6-prenyl-naringenin, was thought to be one of the active components. These results suggested that licorice leaf extract may be a useful ingredient for skin care due to the synthesis of intercellular lipids and HA [source] N-Palmitoyl-4-Hydroxy- L -Proline Palmityl Ester: A Pseudoceramide that Provides Efficient Skin Barrier Repair and ProtectionINTERNATIONAL JOURNAL OF COSMETIC SCIENCE, Issue 1 2006G. Vielhaber Ceramides are the main constituents of the epidermal permeability barrier, and it has been demonstrated that the application of ceramide enriched creams promotes epidermal barrier repair. However, nature-identical ceramides are extremely expensive and difficult to formulate. We therefore developed a new pseudoceramide, N-palmitoyl-4-hydroxy- l -proline palmityl ester (BIO391). Due to its low melting point of £60°C the pseudoceramide BIO391 can easily be incorporated into cosmetic formulations. In addition, it is very safe for use in cosmetics. The efficacy of the pseudoceramide BIO391 was investigated in vivo in a model for detergent-induced barrier disruption. Trans-epidermal water loss, redness, and skin hydration were recorded before and after barrier disruption as well as during the subsequent 9-day treatment with the test products. Barrier repair of skin treated with the pseudoceramide BIO391 was accomplished earlier than that of untreated and vehicle treated skin. Optimum barrier repair was achieved with 1.0% pseudoceramide BIO391 and optimum erythema reduction with 0.5% pseudoceramide BIO391. The optimum dosage could be reduced to 0.1% pseudo-ceramide by synergistic combination with 0.1% (-)-a-bisabolol. In addition, the pseudoceramide BIO391 proved to be as effective as nature-identical ceramides 2 and 3. In summary, N-palmitoyl-4-hydroxy- l -proline palmityl ester is a highly efficient barrier repair agent with efficacy equivalent to that of nature-identical ceramides, and it has excellent formulation properties. [source] Clinical and instrumental evaluation of a food supplement in improving skin hydrationINTERNATIONAL JOURNAL OF COSMETIC SCIENCE, Issue 4 2005G Primavera Synopsis Topically applied cosmetic products can be helpful in improving skin hydration. The study shows how oral supplementation could be helpful in improving and preventing the skin dehydration. A total of 32 healthy female volunteers entered the study. Of which, 16 were treated with a food supplement based on vegetable ceramides, amino acids, fish cartilage, antioxidants and essential fatty acids for 40 days and 16 with placebo. The results of the clinical and instrumental evaluations carried out in this study, have highlighted how the active treatment is effective in improving skin hydration and in reducing the cutaneous smoothness and roughness and the depth of furrows, in comparison to the placebo. In fact, concerning several important parameters, as stratum corneum hydration and skin roughness, the improvement measured exceeded 25%. We therefore suggest that a combination of treatments (oral and topical) can be more effective in improving skin hydration. Resume L'application topique de produits cosmétiques peut aider à l'hydratation de la peau. L'étude montre comment une supplémentation orale peut améliorer et empêcher la déshydratation de la peau. Trente deux femmes volontaires en bonne santé ont participéà cette étude. Seize ont été traitées pendant quarante jours avec un supplément alimentaire contenant des céramides végétaux, des aminoacides, du cartilage de poisson, des antioxydants et des acides gras essentiels, seize autres ont reçu un placebo. Les résultats des évaluations cliniques et expérimentales menées dans cette étude ont montré comment le traitement actif est efficace pour améliorer, par rapport au placebo, l'hydratation de la peau et réduire la douceur, la rugosité cutanée et la profondeur des rides. En fait, si l'on considère des paramètres importants comme l'hydratation du stratum corneum et la rugosité de la peau, l'amélioration mesurée dépasse 25%. Nous suggérons également qu'une combinaison de traitements (oral et topique) peut être encore plus efficace. [source] Original semiologic standardized evaluation of stratum corneum hydration by Diagnoskin® stripping sampleINTERNATIONAL JOURNAL OF COSMETIC SCIENCE, Issue 3 2004P. Gasser Synopsis In a normal and healthy skin, the regular elimination of the superficial corneocytes, called desquamation, is a fundamental physiologic process intended to protect the barrier function of the skin. This invisible loss of corneocytes, individually or in small groups, is incessantly compensated by the divisions of the proliferative layer and the upward cellular maturation in order to maintain the harmonious renewal of the epidermis and the integrity of the stratum corneum. The harmony of this desquamation process is intimately conditioned by a sufficient hydration of the stratum corneum: (i) an abnormal desquamation leads to a disruption of the water barrier function and consequently to a dehydration tendency of the stratum corneum, and (ii) a cutaneous dryness (whatever the cause) is able to disturb the desquamation process. Protecting the water content of the stratum corneum has always been a major preoccupation of the cosmetic industry scientists. Consequently, the moisturizing properties of a cosmetic product are objectively measured by various explorations directly targeted on the hydration (corneometry) and on the level of the water barrier function (transepidermal water loss (TEWL) measurements), which depends directly on the skin hydration state. This intimate linkage of the desquamation process and the water content of the stratum corneum enable us to suggest an indirect assessment of the hydration from a direct study of the desquamation by examining a skin-stripping sample (D-Squames®) by an optical microscope (linked to a computer). We will describe this already known technique and mainly its new and unpublished semiologic exploitation, named Diagnoskin®, whose advantages are its simplicity and its reproducibility particularly interesting in the case of sequential appraisal of dermatologic or cosmetic treatments. Résumé Sur une peau normale et saine, l'élimination régulière des cornéocytes superficiels, appelée desquamation, est un processus physiologique fondamental destinéà préserver la fonction barrière de la peau. La perte invisible des cornéocytes, individuellement ou par petits paquets cellulaires, est sans cesse compensée par les divisions de la couche germinative et la maturation cellulaire ascensionnelle afin de maintenir le renouvellement harmonieux de l'épiderme et l'intégrité du stratum corneum. L'harmonie de ce processus de desquamation est intimement conditionnée par une hydratation suffisante du stratum corneum: une desquamation anormale aboutit à une perturbation de la fonction barrière et donc à une tendance à la déshydratation du stratum corneum, Une sècheresse cutanée (quelle qu'en soit la cause) va perturber la desquamation. Préserver la teneur en eau du stratum corneum est depuis toujours une préoccupation majeure pour le scientifique de l'industrie cosmétique. L'appréciation objective du caractère hydratant d'une crème cosmétique est d'ailleurs mesuré par diverses explorations directement ciblées sur l'hydratation (cornéométrie) et sur l'état de la fonction barrière (Perte Insensible en Eau ,PIE) qui dépend directement de l'état d'hydratation de la peau. Cette liaison intime du niveau d'hydratation du stratum corneum et du phénomène de desquamation nous a fait proposer une évaluation indirecte de l'hydratation à l'aide d'une étude directe de la desquamation par observation au microscope (reliéà un ordinateur) des prélèvements par stripping des cornéocytes superficiels (D-Squames®). Nous décrirons cette technique déjà connue et surtout son exploitation sémiologique nouvelle et inédite, appelée Diagnoskin® dont les avantages sont sa simplicité et son caractère reproductible particulièrement intéressants pour l'évaluation séquentielle de traitements dermatologiques ou cosmétiques. [source] Effects of lipid nanocarriers on the performance of topical vehicles in vivoJOURNAL OF COSMETIC DERMATOLOGY, Issue 2 2009Mojgan Moddaresi PharmD Summary Background/aims, Nanocarrier systems have been extensively studied for their suitability in personal care formulations. Theoretically, they could enhance skin delivery of active compounds, thereby improving in vivo efficacy of the products. As such the aim of this study was to evaluate the effect of a lipid nanocarrier (LNC) system loaded with tocopheryl acetate (TA) on the hydration, biomechanical properties, and antioxidant capacity of human skin, when used in two different vehicles, and compare it with a non-LNC formulation. Methods, TA-loaded lipid nanocarriers (TA-LNCs) were produced by the phase inversion method, using physiological lipids and purified by ultra-centrifugation. They were incorporated into a hydrophilic gel and foam, and their performance compared with a saturated TA solution in silicon oil. Skin hydration and biomechanical properties were measured by means of a corneometer and a cutometer, respectively, while a high-resolution spectrophotometer was used to assess skin redness after stimulation by methyl nicotinate in a micro-inflammatory test. Both short-term (3 h) and long-term trials (4 weeks) were performed. Results, The results confirmed that the LNCs enhanced skin hydration in both studies, while skin viscoelastic parameters remained practically unchanged during the 4-week study. The antioxidant assessment failed to show significant difference between the test sites. Conclusions, TA-loaded LNCs exhibited the ability to enhance skin hydration, while their effect on skin biomechanical properties and on antioxidant efficacy could not be statistically proved. [source] Skin hydration: a review on its molecular mechanismsJOURNAL OF COSMETIC DERMATOLOGY, Issue 2 2007Sylvie Verdier-Sévrain MD Summary Water is absolutely essential for the normal functioning of the skin and especially its outer layer, the stratum corneum (SC). Loss of water from the skin must be carefully regulated, a function dependent on the complex nature of the SC. The retention of water in the SC is dependent on two major components: (1) the presence of natural hygroscopic agents within the corneocytes (collectively referred to as natural moisturizing factor) and (2) the SC intercellular lipids orderly arranged to form a barrier to transepidermal water loss (TEWL). The water content of the SC is necessary for proper SC maturation and skin desquamation. Increased TEWL impairs enzymatic functions required for normal desquamation resulting in the visible appearance of dry, flaky skin. There have been recent discoveries regarding the complex mechanisms of skin hydration. In particular, it has been discovered that glycerol, a well-known cosmetic ingredient, exists in the SC as a natural endogenous humectant. Hyaluronan, which has been regarded mainly as dermal component, is found in the epidermis and is important for maintaining normal SC structure and epidermal barrier function. More importantly, the discovery of the existence of the water-transporting protein aquaporin-3 in the viable epidermis and the presence of tight junction structures at the junction between the stratum granulosum and SC have brought new insights into the mechanisms of skin water distribution and barrier function. [source] Prediction of steady-state skin permeabilities of polar and nonpolar permeants across excised pig skin based on measurements of transient diffusion: Characterization of hydration effects on the skin porous pathwayJOURNAL OF PHARMACEUTICAL SCIENCES, Issue 8 2002Hua Tang Abstract The applicability of a two-parameter Fickian diffusion model for predicting the skin steady-state permeability based on measurements of the transient transport of permeants across the skin was tested. Using five model permeants possessing different physicochemical properties and pig skin as the model membrane, the skin permeabilities predicted by the two-parameter Fickian diffusion model were compared with the measured skin permeabilities. Results show that the transient skin permeation profiles of the hydrophobic permeants, estradiol, testosterone, and dolichol, across split-thickness pig skin can be modeled adequately by the two-parameter Fickian diffusion model (with constant parameter values), and therefore, that this model can be utilized to shorten the experimental time required to determine the skin permeabilities of these compounds. However, the skin permeabilities of the highly hydrophilic permeants, mannitol and sucrose, predicted by the two-parameter Fickian diffusion model (with constant parameter values) were significantly lower than the experimentally determined values, indicating that the dominant skin pathway of polar permeants within the excised pig skin undergoes significant structural changes during the in vitro diffusion cell studies. Although the skin permeability values determined experimentally using the traditional steady-state method normally correspond to a highly hydrated skin sample, the two-parameter Fickian diffusion model enables an estimation of the skin permeability of the skin membrane at its less-hydrated state (a condition more representative of in vivo and clinical situations). Using the two-parameter Fickian diffusion model and a recently developed skin porous-pathway theory, the effects of skin hydration on the skin porous pathway within the excised pig skin were characterized. Specifically, we found that hydration leads to induction of new pores/reduction of the tortuosity of existing pores within the excised pig skin during the 48 h diffusion cell studies conducted, while the skin average pore radii remain relatively constant (,26 Å) for up to 48 h. © 2002 Wiley-Liss Inc. and the American Pharmaceutical Association J Pharm Sci 91:1891,1907, 2002 [source] Skin hydration and possible shunt route penetration in controlled estradiol delivery from ultradeformable and standard liposomesJOURNAL OF PHARMACY AND PHARMACOLOGY: AN INTERNATI ONAL JOURNAL OF PHARMACEUTICAL SCIENCE, Issue 10 2001Gamal M. M. El Maghraby Human skin delivery of estradiol from ultradeformable and traditional liposomes was explored, comparing occlusive and open application, with the aim of examining the role of skin hydration. Partially hydrated epidermis was used for open hydration, but fully hydrated membranes were used for occluded studies. In addition, we developed a novel technique to investigate the role of shunt route penetration in skin delivery of liposomal estradiol. This compared delivery through epidermis with that through a stratum corneum (SC)/epidermis sandwich from the same skin with the additional SC forming the top layer of the sandwich. This design was based on the fact that orifices of shunts only occupy 0.1% of skin surface area and thus for SC/epidermis sandwiches there will be a negligible chance for shunts to superimpose. The top SC thus blocks most shunts available on the bottom membrane. If shunts play a major role then the delivery through sandwiches should be much reduced compared with that through epidermis, taking into consideration the expected reduction owing to increased membrane thickness. After open application, both ultradeformable and traditional liposomes improved estradiol skin delivery, with the ultradeformable liposomes being superior. Occlusion reduced the delivering efficiency of both vesicle types, supporting the theory that a hydration gradient provides the driving force. Shunt route penetration was found to play only a very minor role in liposomal delivery. In conclusion, full hydration of skin reduces estradiol delivery from liposomes and the shunt route is not the main pathway for this delivery. [source] Surfactants, skin cleansing protagonistsJOURNAL OF THE EUROPEAN ACADEMY OF DERMATOLOGY & VENEREOLOGY, Issue 1 2010M Corazza Abstract The correct choice of cosmetic products and cleansers is very important to improve skin hydration, to provide moisturizing benefits and to minimize cutaneous damage caused by surfactants. In fact, surfactants may damage protein structures and solubilize lipids. Soaps, defined as the alkali salts of fatty acids, are the oldest surfactants and are quite aggressive. Syndets (synthetic detergents) vary in composition and surfactant types (anionic, cationic, amphotheric, non-ionic). These new skin cleansing products also contain preservatives, fragrances, and sometimes emollients, humectants and skin nutrients. We present a revision of the literature and discuss recent findings regarding skin cleansers. [source] Changes in Diapered and Nondiapered Infant Skin Over the First Month of LifePEDIATRIC DERMATOLOGY, Issue 1 2000Marty O. Visscher Ph.D. Diapered and nondiapered skin sites were contrasted to the volar forearm of adults (mothers). Thirty-one term infants were evaluated in the hospital on postnatal day 1 and at home on days 4, 7, 14, 21, and 28 for a total of six visits. Measurements included baseline skin hydration, continuous capacitive reactance, peak water sorption, rate of water desorption, skin pH, skin temperature, and environmental conditions. Changes in epidermal barrier properties over the first 4 weeks of life included an increase in surface hydration, a decrease in transepidermal water movement under occlusion, a decrease in surface water desorption rate, and a decrease in surface pH. Diapered and nondiapered regions were indistinguishable at birth but exhibited differential behavior over the first 14 days, with the diapered region showing a higher pH and increased hydration. Maternal measurements remained constant throughout the period. We conclude that healthy newborn skin undergoes progressive changes in epidermal barrier properties over the first 28 days. Adult skin testing does not replicate newborn skin during the first month of life. [source] A full-UV spectrum absorbing daily use cream protects human skin against biological changes occurring in photoagingPHOTODERMATOLOGY, PHOTOIMMUNOLOGY & PHOTOMEDICINE, Issue 4 2000S. Seité Background: There is overwhelming evidence that exposure of human skin to ultraviolet radiations (UVR) leads to the development of cutaneous photoaging and eventually to neoplasia. This study was designed to evaluate in humans the protection afforded by a daily use cream containing a photostable combination of UVB and UVA absorbers (Uvinul® N539, Parsol® 1789 and Mexoryl® SX) providing a continuous absorption through the entire UV spectrum, against damages induced by repeated daily exposure to solar simulated radiation (SSR). Methods: Buttock skin of 12 healthy volunteers was exposed 5 days per week for 6 weeks to one minimal erythema dose of solar simulated radiation per exposure. The following parameters in treated and untreated skin were evaluated: erythema, pigmentation, skin hydration, skin microtopography, histology and immunochemistry, and collagen and metalloproteinase (MMP) mRNA levels. Results: In SSR exposed unprotected skin sites, we observed melanization and changes in the skin hydration and microtopography. The epidermis revealed a significant increase in stratum corneum and stratum granulosum thickness. In the dermis, an enhanced expression of tenascin and a reduced expression of type I pro-collagen were evidenced just below the dermal epidermal junction. Although we were unable to visualize any change in elastic fibers in exposed buttock skin, a slightly increased deposition of lysozyme and alpha 1 antitrypsin on these fibers was observed using immunofluorescence techniques. Furthermore, types I and III collagen mRNA were slightly increased and a significant enhancement (up to 2.8-fold) of MMP-2 mRNA level was observed. The daily use cream was shown to prevent all these biological changes. Conclusion: Our results show in vivo that an appropriate full-UV spectrum product significantly reduces the solar-UV-induced skin damage, demonstrating the benefit of daily photoprotection. [source] Aquaporin-3 gene and protein expression in sun-protected human skin decreases with skin ageingAUSTRALASIAN JOURNAL OF DERMATOLOGY, Issue 2 2010Ji Li ABSTRACT Backgroud/Objectives:, Aquaporin 3 (AQP3) is a protein implicated in skin hydration. AQP3 null mice have relatively dry skin, reduced skin elasticity, and delayed recovery of barrier function after removal of the stratum corneum which is also present in skin of old people. A feature of skin aging is the change in both water content and barrier function of the skin. We investigated the expression of aquaporin 3 in non sun-exposed human skin, normal human keratinocytes and fibroblasts from different age groups to further understand the relationship between AQP3 and intrinsic skin aging. Methods:, We investigated the expression of aquaporin3 (AQP3) in normal human skin, normal human epidermal keratinocytes (NHEK) and skin fibroblast of different ages by immunohistochemistry, immunocytochemistry, the reverse transcription-polymerase chain reaction (RT-PCR) and western blotting. The samples were derived from 60 patients of varying ages: <20 years of age, 30,45 years and >60 years of age. Twenty skin biopsies, 6 for keratinocyte/fibroblast cultures, were taken from each age group. Results:, AQP3 decreased with increasing age in both skin and NHEK samples. We demonstrated significant differences in AQP3 expression between the 3 age groups (P < 0.05). In fibroblasts, AQP3 expression levels were significantly lower in the >60 year olds compared to 30,45 year olds (P < 0.05) and <20 year olds (P < 0.05), there was no significant difference between the two younger groups (P > 0.05). Conlusions:, AQP3 may be involved in the intrinsic aging process of non sun-exposed human skin. [source] Near-IR spectroscopic imaging for skin hydration: The long and the short of itBIOPOLYMERS, Issue 2 2002E. Michael Attas Abstract Near-IR spectroscopic methods have been developed to determine the degree of hydration of human skin in vivo. Noncontact reflectance spectroscopic imaging was used to investigate the distribution of skin moisture as a function of location. A human study in a clinical setting has generated quantitative data showing the effects of a drying agent and a moisturizer on delineated regions of the forearms of eight volunteers. Two digital imaging systems equipped with liquid-crystal tunable filters were used to collect stacks of monochromatic images at 10-nm intervals over the 650,1050 and 960,1700 nm wavelength bands. Synthetic images generated from measurements of water absorption band areas at three different near-IR wavelengths (970, 1200, and 1450 nm) showed obvious differences in the apparent distribution of water in the skin. Changes resulting from the skin treatments were much more evident in the long-wavelength images than in the short-wavelength ones. The variable sensitivity of the method at different wavelengths has been interpreted as being the result of different penetration depths of the IR light used in the reflectance studies. © 2002 John Wiley & Sons, Inc. Biopolymers (Biospectroscopy) 67: 96,106, 2002 [source] Artificial disruption of skin barrier prior to irritant patch testing does not improve test designBRITISH JOURNAL OF DERMATOLOGY, Issue 1 2004K.L. Gebhard Summary Background, Irritant patch testing is often performed as a 24- or 48-h occlusive patch test with low concentrations of sodium lauryl sulphate (SLS). Objectives, The aim of this study was to investigate potential ways to shorten this test procedure and obtain precise test results. Patients and methods, Thirty-six healthy volunteers underwent irritant patch testing with different pretreatments (PT) of the test fields. Occlusive test chambers were applied on the upper back with SLS 0·5%, 1%, 2% and 5% in large Finn Chambers®. The patches were removed after 4 and 24 h, respectively, depending on the concentration used. Test fields were pretreated as follows: PT 0, field without any PT (control); PT 1, prick with lancet; PT 2, prick with test stamp; PT 3, scratch with lancet; PT 4, incision with standardized incision instrument (0·1,0·2 mm depth). Skin reactions were evaluated by transepidermal water loss (TEWL), skin erythema and skin hydration and as well by a visual score (VS) at 4, 24 and 72 h. Results, Our data show an obvious distinction between PT 0,2 and PT 3,4 at all measurement methods. The average TEWL values with PT 3,4 were higher than those with PT 0,2, especially on the 4-h course. This distinction may derive from the shape and size of the skin impairment achieved by PT 3,4, leading to a mechanical barrier disruption. However, SLS may infiltrate directly into deeper skin layers supported by capillarity. Consequently, no or little penetration through the epidermis and interaction with its structures occurs, which is responsible for irritant skin reactions. The SLS dose in the upper skin layers is therefore lower at these PTs. The lower remaining dose of SLS also explains this distinction, especially for the VS. Additionally, there are presumed reactions in deeper layers of the epidermis and dermis at PT 3,4. Conclusions, In summary, all data suggest a different reaction pattern from the classical irritant response. Therefore, application without any PT seems to be best suited for irritancy skin testing, especially for visual assessment. PTs prior to irritant patch testing have been shown to be unjustifiable. [source] | |||||||||||||