Increase In Transepidermal Water Loss Research Articles

Inhibitory effect of vitamin C on intrinsic aging in human dermal fibroblasts and hairless mice.

Vitamin C significantly reduced senescence-associated β-galactosidase (SA-β-gal) activity, with both the suppression of cell-cycle inhibitors (p53, p21, p16, and pRb) and stimulation of cell-cycle activators (E2F1 and E2F2). Vitamin C also effectively attenuated the hyperactivation of the phosphatidylinositol 3-kinase (PI3K)/protein kinase-B (AKT) signaling pathway. The expression of the longevity marker, the mammalian target of rapamycin (mTOR), was down-regulated by vitamin C while the expressions of forkhead box O3a (FoxO3a) and sirtuin1 (SIRT1) were up-regulated by vitamin C. In the middle-aged (MA) mice, oral administration of vitamin C significantly inhibited wrinkle formation, skin atrophy, and loss of elasticity through increasing collagen and elastic fiber. The increase in transepidermal water loss and the decrease in skin hydration were recovered by vitamin C treatment in the MA mice. Overall, vitamin C effectively prevents cellular senescence in vitro and in vivo suggesting it has protective potential against natural aging of the skin.

Specific dermatological benefits associated with quantities of lotion transferred to the skin.

A growing number of manufacturers are taking advantage of the ability of absorbent consumer products to deliver lotion to the skin. The lotion is included on these products to help protect the skin from adverse skin effects that can occur, including: (1) irritation, (2) over hydration of the stratum corneum, (3) dryness that can occur from extended exposure to highly absorbent consumer products, and (4) changes in pH. This manuscript presents results of a quantitative lotion transfer study of adult incontinence products. Resulting lotion transfer is compared to the results of several separate experiments in which specific skin benefits have been correlated to lotion concentrations. The behind-the-knee (BTK) lotion transfer protocol was used to quantitate lotion transfer from adult incontinence (AI) test products constructed using 2 lotion formulations and 2 configurations of lotion application. A modified arm patch protocol, in which skin sites of a measured dimension were pre-treated with specific volumes of lotion, was used to evaluate protective effects of lotion against exposure to irritants, and over hydration from wetted absorbent products. After a 6-hours continuous exposure in the BTK the 5-stripe lotion configuration products transferred (adjusted mean±SE) 94±11-104±11μg/cm2 lotion. After 24hours of wear, transfer had increased to 127±22 and 149±24μg/cm2 , respectively. The single-block configuration products transferred 289±10-316±10μg/cm2 (P=.04). Transfer after 24hours of wear was 328±23 and 472±21μg/cm2 , respectively (P<.0001). Several protocols were used to evaluate the concentration of lotion required to provide four specific skin benefits. In studies evaluating protection against irritants, skin site pre-treated with lotion were patched with 0.5% sodium lauryl sulfate (SLS). Protective effects were assessed by visual assessment of erythema and trans-epidermal water loss (TEWL). In the first experiment, lotion pre-treatment concentrations as low as 165μg/cm2 exhibited significantly (P<.05) lower erythema and TEWL compared to the positive irritant control (ie, no lotion pre-treatment and SLS only). In the second experiment, lotion pre-treatment concentrations of 80μg/cm2 (P=.018) exhibited significantly (P=.018) lower TEWL. In two studies on protection from over hydration, lotion pre-treatment sites were subsequently patched with wetted absorbent consumer products. The change in TEWL was used as a measure of over hydration. Lotion concentrations significantly reduced the increase in TEWL at 80μg/cm2 (P=.007) and 70μg/cm2 (P≤.05). A BTK study was used to evaluate the ability of lotion to prevent dryness. After 6hours of wear, test products transferring lotion concentrations of 110 or 133μg/cm2 produced significantly lower scores for dryness compared to products transferring 48 or 69μg/cm2 . Using collagen sheets to mimic the stratum corneum, an in vitro study was conducted to measure the ability of lotion to prevent passage of high pH buffer solution. Results demonstrated that the lowest concentration of lotion that was tested (110μg/cm2 ) interfered with passage of the high pH buffer through the collagen sheet, delaying the rise in pH. We can conclude that pretreatment with 110μg/cm2 lotion acts as a barrier to high pH fluids such as urine. Using the measurement of lotion transfer from the AI products, together with the results of studies conducted to determine the concentration of lotion required to provide specific skin benefits, we conclude that the five-stripe lotion configuration AI test products transferred enough lotion (ie, ≥80μg/cm2 ) to provide skin protection with regard to: (1) irritant effects and (2) excess moisture. The single-block AI test products also transferred enough lotion to provide these skin benefits (ie, ≥165μg/cm2 ), and the additional benefits of skin protection against: (3) dryness, and (4) changes in pH.

Fractionated aliphatic alcohols as synthetic precursors of ultra long-chain monoacylglycerols for cosmetic applications.

Xerosis is an abnormally dry and flaky skin condition that is associated with a change in the packing behaviour of the lipid matrix in the stratum corneum (SC), the outermost layer of the skin. This skin condition can lead to an increase in transepidermal water loss (TEWL). As ultralong-chain fatty acids have a positive effect on maintaining the packing behaviour of the SC lipid matrix, a moisturizer which contains glycerides of ultralong-chain fatty acids could act as a semi-occlusive layer on the surface of the skin. This will lower the rate of water evaporation through the epidermis and consequently help prevent or improve skin xerosis. To identify a novel source of ultralong-chain lipids and develop monoacylglycerols with mixed fatty acyl chain lengths that have occlusive properties superior to petrolatum. Initially, Performacol 425, a mixture of very long-chain fatty alcohols, was fractionated using short path distillation to yield a fraction enriched with C22:0-C26:0 fatty alcohols. The fatty alcohol fraction was then oxidized using Jones reagent, and the resulting fatty acids were esterified with glycerol to yield the corresponding monoglycerides using Novozym 435. These were then evaluated using Fourier transform infrared spectroscopy, differential scanning calorimetry and water vapour transmission rate measurements. The monoacylglycerols enriched with C22:0-C26:0 displayed a melting point of 80°C and orthorhombic packing; packing behaviour mainly present in healthy SC. In addition, a phospholipid-structured emulsion containing 3% of the monoglycerides displayed occlusive properties superior to the vehicle containing 3% petrolatum jelly. Performacol 425 can be a potential source of fatty alcohols to synthesize monoacylglycerols that can improve the occlusive behaviour of phospholipid-structured emulsions.

473 The stratum corneum paradox: Improving bioavailability of active molecules while reinforcing the skin barrier

Stratum corneum (SC) has to be impermeable to protect our body from external aggression and also excessive water loss. Nevertheless, to be efficient, cosmetic active ingredients must cross the SC barrier to achieve the viable cells of epidermis. A vast range of penetration enhancers has been developed following two different mechanisms: Modifying the skin polarity; Interruption of the intercellular lipid packing by delipidation leading to an increase of trans-epidermal water loss and dehydration. Knowing that consumers are increasingly seeking cosmetic products providing better results and rapid efficacy, the challenge of cosmetics industry is to improve the bioavailability of active molecules without destroying the barrier function of the SC and decreasing its hydration. In this way, we developed a phospholipid lamellar system (hydrogenated phospholipids and fatty acids) based on SC chemical and structural biomimicry using polarity modification mechanism. When applied on the skin, hydrogenated phospholipids first fuse with the skin surface forming a non-permeable and occlusive gel linked to the phospholipid organization into lamellar rigid one-dimensional network (Structural biomimicry). Furthermore, fatty acids interact with the intercorneocytar lipid cement of the SC and modify its structure leading to the creation of a water vacuoles facilitating the permeation of hydrophilic molecules through the membrane (chemical biomimicry). Different studies were performed to understand the impact of the phospholipid lamellar system on the integrity of the SC (TEWL, corneometry, electron microscopy, D-squam) and on the active ingredients permeation (bioavailability study). To conclude, the obtained results confirmed that our optimized lipid mixture meet the challenge of improving the bioavailability of active ingredients, by increasing the hydration of the SC and reinforcing its integrity.

Preventive effect of dietary astaxanthin on UVA-induced skin photoaging in hairless mice.

Astaxanthin, a carotenoid found mainly in seafood, has potential clinical applications due to its antioxidant activity. In this study, we evaluated the effect of dietary astaxanthin derived from Haematococcus pluvialis on skin photoaging in UVA-irradiated hairless mice by assessing various parameters of photoaging. After chronic ultraviolet A (UVA) exposure, a significant increase in transepidermal water loss (TEWL) and wrinkle formation in the dorsal skin caused by UVA was observed, and dietary astaxanthin significantly suppressed these photoaging features. We found that the mRNA expression of lympho-epithelial Kazal-type-related inhibitor, steroid sulfatase, and aquaporin 3 in the epidermis was significantly increased by UVA irradiation for 70 days, and dietary astaxanthin significantly suppressed these increases in mRNA expression to be comparable to control levels. In the dermis, the mRNA expression of matrix metalloprotease 13 was increased by UVA irradiation and significantly suppressed by dietary astaxanthin. In addition, HPLC-PDA analysis confirmed that dietary astaxanthin reached not only the dermis but also the epidermis. Our results indicate that dietary astaxanthin accumulates in the skin and appears to prevent the effects of UVA irradiation on filaggrin metabolism and desquamation in the epidermis and the extracellular matrix in the dermis.

Correction: IL-31-Driven Skin Remodeling Involves Epidermal Cell Proliferation and Thickening That Lead to Impaired Skin-Barrier Function.

[This corrects the article DOI: 10.1371/journal.pone.0161877.].

Influence of Repeated Senna Laxative Use on Skin Barrier Function in Mice.

BackgroundSenna, one of the major stimulant laxatives, is widely used for treating constipation. Chronic senna use has been reported to be associated with colonic disorders such as melanosis coli and/or epithelial hyperplasia. However, there is no obvious information on the influence of chronic senna use on organs except for the intestine.ObjectiveTo clarify the influence of senna laxative use on skin barrier function by repeated senna administration.MethodsEight-week-old male hairless mice received senna (10 mg/kg/day) for 21 days. After administration, we evaluated transepidermal water loss (TEWL), and investigated the biomarkers in plasma and skin using protein analysis methods.ResultsFecal water content on day seven was significantly increased; however, on day 21, it was significantly decreased after repeated senna administration. In the senna-administered group, TEWL was significantly higher compared to the control on days seven and 21. Plasma acetylcholine concentration and NO2 −/NO3 − were increased on days seven and 21, respectively. In skin, tryptase-positive mast cells and inducible nitric oxide synthase (iNOS)-positive cells were increased on days seven and 21, respectively. The increase of TEWL on days seven and 21 was suppressed by the administration of atropine and N(G)-nitro-L-arginine methyl ester, respectively.ConclusionIt was suggested that diarrhea or constipation induced by repeated senna administration caused the impairment of skin barrier function. There is a possibility that this impaired skin barrier function occurred due to degranulation of mast cells via cholinergic signals or oxidative stress derived from iNOS.

Atopic Dermatitis: Pathophysiology.

The pathophysiology of atopic dermatitis is complex and multifactorial, involving elements of barrier dysfunction, alterations in cell mediated immune responses, IgE mediated hypersensitivity, and environmental factors. Loss of function mutations in filaggrin have been implicated in severe atopic dermatitis due to a potential increase in trans-epidermal water loss, pH alterations, and dehydration. Other genetic changes have also been identified which may alter the skin's barrier function, resulting in an atopic dermatitis phenotype. The imbalance of Th2 to Th1 cytokines observed in atopic dermatitis can create alterations in the cell mediated immune responses and can promote IgE mediated hypersensitivity, both of which appear to play a role in the development of atopic dermatitis. One must additionally take into consideration the role of the environment on the causation of atopic dermatitis and the impact of chemicals such as airborne formaldehyde, harsh detergents, fragrances, and preservatives. Use of harsh alkaline detergents in skin care products may also unfavorably alter the skin's pH causing downstream changes in enzyme activity and triggering inflammation. Environmental pollutants can trigger responses from both the innate and adaptive immune pathways. This chapter will discuss the multifaceted etiology of atopic dermatitis which will help us to elucidate potential therapeutic targets. We will also review existing treatment options and their interaction with the complex inflammatory and molecular triggers of atopic dermatitis.

Skin targeting of resveratrol utilizing solid lipid nanoparticle-engrossed gel for chemically induced irritant contact dermatitis.

Irritant contact dermatitis (ICD) is a chronic and relapsing skin disease with severe eczematous lesions. Despite its growing prevalence, therapeutic treatments remain limited. Long-term topical corticosteroid treatment can induce skin atrophy, hypopigmentation, and increase in transepidermal water loss. An innovative dermal treatment is essential to reduce the side effects of corticosteroids. Topical resveratrol (RES), although effective for ICD, is a challenging molecule due to low solubility and poor bioavailability. The objective of this work was to build RES-loaded solid lipid nanoparticles (RES-SLNs) with skin targeting. For this purpose, RES-SLNs were prepared using the probe ultrasonication method utilizing Precirol ATO 5 and Tween 20. The RES-SLNs were evaluated for particle size, entrapment efficiency (EE), and transmission electron microscopy (TEM) studies. Further, RES-SLNs were incorporated into Carbopol gel and investigated for ex vivo skin permeation, deposition study on human cadaver skin, and finally skin irritation study on New Zealand White rabbits. It was further assessed for possible beneficial effects on ICD using BALB/c mice. RES-SLN showed mean size below 100nm and 68-89% EE. TEM studies confirmed spherical particles in the nanometer range. An ex vivo study of RES-SLN-loaded gel exhibited controlled drug release up to 24h; similarly, in vitro drug deposition studies showed potential of skin targeting with no skin irritation. RES-SLN gel confirmed competent suppression of ear swelling and reduction in skin water content in the BALB/c mouse model of ICD when compared to marketed gel. Thus, the formulated RES-SLN gel would be a safe and effective alternative to conventional vehicles for treatment of ICD.

Effects of two different fabrics on skin barrier function under real pressure conditions

BackgroundPressure Ulcers (PUs) are a severe form of skin and soft tissue lesions, caused by sustained deformation. PU development is complex and depends on different factors. Skin structure and function change during prolonged loading on PU predilection sites and surfaces being in direct contact with skin are likely to have an impact as well. Little is known about the influence of fabrics on skin function under pressure conditions. ObjectivesTo investigate skin responses to sustained loading in a sitting position and possible differences between two fabrics. MethodsUnder controlled conditions 6 healthy females (median age 65.0 (61.0–67.8) years) followed a standardized immobilization protocol of a sitting position for 45 min on a spacer and on a cotton fabric. Before and after the loading period skin surface temperature, stratum corneum hydration, transepidermal water loss (TEWL), erythema, skin elasticity and ’relative elastic recovery‘ were measured at the gluteal areas. ResultsA 45 min sitting period caused increases of skin surface temperature and erythema independent of the fabric. Loading on spacer fabric showed a two times higher increase of TEWL compared to cotton. Stratum corneum hydration showed slight changes after loading, skin elasticity and ’relative elastic recovery’ remained stable. ConclusionsSitting on a hard surface causes skin barrier changes at the gluteal skin in terms of stratum corneum hydration and TEWL. These changes are influenced by the fabric which is in direct contact to the skin. There seems to be a dynamic interaction between skin and fabric properties especially in terms of temperature and humidity accumulation and transport.

IL-31-Driven Skin Remodeling Involves Epidermal Cell Proliferation and Thickening That Lead to Impaired Skin-Barrier Function.

Interleukin-31 (IL-31) is a type 2 helper T-cell-derived cytokine that has recently been shown to cause severe inflammation and tissue remodeling in multiple chronic diseases of the skin and lungs. IL-31 is upregulated in allergic and inflammatory diseases, including atopic dermatitis, asthma, cutaneous T-cell lymphomas, and allergic rhinitis, as well as autoimmune diseases such as systemic erythematosus. Overexpression of IL-31 in T cells causes severe inflammation, with histological features similar to skin lesions of patients with atopic dermatitis. However, the molecular mechanisms involved in IL31-driven pathological remodeling in skin diseases remain largely unknown. Here, we studied the role of IL-31 in skin damage as a result of intradermal administration of recombinant IL-31 into mice. Notably, IL-31 was sufficient to increase epidermal basal-cell proliferation and thickening of the epidermal skin layer. Our findings demonstrate a progressive increase in transepidermal water loss with chronic administration of IL-31 into the skin. Further, analysis of the skin transcriptome indicates a significant increase in the transcripts involved in epidermal-cell proliferation, epidermal thickening, and mechanical integrity. In summary, our findings demonstrate an important role for IL-31 signaling in epidermal cell proliferation and thickening that together may lead to impaired skin-barrier function in pathological remodeling of the skin.

353 Mouse model of cutaneous adverse effects: Validation with human topical therapies

The discovery of novel topical drugs would benefit from an in vivo screening model to predict unwanted cutaneous effects. With this aim, we established a subacute mouse model and validated it with five approved topical formulations which show cutaneous side effects. Formulations tested were Clovate®-clobetasol cream, Dermosa hidrocortisona®-hydrocortisone cream, Zorac®-tazarotene, Efudix®-5-fluorouracil and Picato®-ingenol mebutate. Mice received a topical application of the test product on dorsal skin once daily for 4 days except for Efudix® (10 applications) and Picato® (single dose). On day 5, skin punch biopsies were taken, weighted and analysed histologically. Additional parameters were also recorded such as macroscopic images, transepidermal water loss (TEWL), body weight and blood cell count. Corticosteroid formulations induced skin atrophy in mice manifested as an increase in TEWL, a punch weight decrease, and epidermis and follicular atrophy. These effects were more severe with Clovate® than with Dermosa hidrocortisona®, in agreement with the distinct corticosteroid potencies. In contrast, Zorac®-treated skin showed signs of irritation accompanied by skin weight increase, epidermal hyperplasia and a dermal neutrophilic infiltrate. Mice treated with Efudix® showed mainly inflammatory epidermal lesions and necrosis and follicular atrophy whereas a single dose of Picato® induced an intense dermal inflammatory neutrophilic infiltrate and epidermal necrosis. Systemic alterations were also observed in treated mice. This mouse model reveals the skin alterations observed in humans for five approved topical therapies. These include the adverse effects reported for corticosteroids and tazarotene, as well as those driving the therapeutic responses in actinic keratosis treatments. As the model is aimed at revealing exclusively cutaneous effects, dose adjustments may be required to minimise systemic involvement. This model may provide a rapid screening assay to detect major local adverse effects induced by new chemical entities.

Toluene downregulates filaggrin expression via the extracellular signal-regulated kinase and signal transducer and activator of transcription–dependent pathways

Toluene downregulates filaggrin expression via the extracellular signal-regulated kinase and signal transducer and activator of transcription–dependent pathways

Effect of microplasma irradiation on skin barrier function

In this paper, we introduce the feasibility of atmospheric-pressure argon microplasma irradiation (AAMI) to promote percutaneous absorption. A hairless Yucatan micropig skin was used for this ex vivo study. After AAMI, the disturbance in the stratum corneum (SC) lipids was observed using attenuated total reflectance-Fourier transform infrared spectroscopy. Also, an increase in transepidermal water loss and no physical damage on pig skins were confirmed by microscopic observation. These results of AAMI were compared with those of a plasma jet irradiation (PJI) and a tape stripping test (TST) leading to the conclusion that AAMI reduces the barrier function of the skin and could also enhance the transdermal absorption of drugs.

Potential for tyndalized Lactobacillus acidophilus as an effective component in moisturizing skin and anti-wrinkle products.

It is widely accepted that ultraviolet (UV) irradiation induces skin damage. In the present study, a UVB-induced hairless mouse model of skin photoaging was developed to determine whether tyndalized Lactobacillus acidophilus was able to significantly enhance the repair of photodamaged skin. To evaluate the effects of tyndalized L. acidophilus on UVB-induced skin-wrinkle formation in vivo, HR-1 hairless male mice were exposed to UVB radiation and orally administered tyndalized L. acidophilus. Compared with the control group, the UVB irradiation mice displayed a significant increase in transepidermal water loss and a reduction in skin hydration. In mice with UVB-induced photodamage, the effacement of the fine wrinkles by tyndalized L. acidophilus was correlated with dermal collagen synthesis, accompanied by histological changes. Furthermore, western blotting was performed to investigate the protein expression levels of matrix metalloproteinases (MMPs) and mitogen-activated protein kinase. Notably, orally administered tyndalized L. acidophilus reduced the expression levels of MMP-1 and MMP-9. Based upon the aforementioned results, it was determined that tyndalized L. acidophilus effectively inhibited the wrinkle formation induced by UVB irradiation, and that this may be attributed to the downregulation of MMPs. Therefore, tyndalized L. acidophilus may be considered a potential agent for preventing skin photoaging and wrinkle formation.

Drug permeation and barrier damage in Leishmania-infected mouse skin.

Pathological disorder can disrupt the barrier integrity of the skin, thereby altering the drug delivery from topical formulations to the target site. Cutaneous leishmaniasis (CL) is an infection of the dermal layers of the skin and manifests as a variety of skin lesions from defined nodular forms to plaques and chronic ulcers. The aim of this work was to characterize the physiology and barrier integrity of the Leishmania-infected BALB/c mouse skin and how they impacted delivery of drugs into the skin. A histological evaluation of the structural differences between uninfected and infected skin was performed using haematoxylin/eosin, elastic Van Gieson and Iba-1 stains. As a CL nodule developed and progressed, the skin pH, hydration and trans-epidermal water loss (TEWL) were recorded. Finally, Franz diffusion cells were used to evaluate the influence of the infection on drug delivery through the skin. We found: (i) structural changes in both the epidermal and dermal layers due to the ingress of inflammatory cells, as shown by immunohistochemistry; (ii) a significant increase in TEWL; and (iii) significantly higher permeation of the model permeants caffeine and ibuprofen and the antileishmanial drugs buparvaquone and paromomycin, for Leishmania-infected skin compared with uninfected skin. The infection had no measurable influence on skin pH and hydration. We report profound changes in the skin barrier physiology, function and permeability to drugs of Leishmania-infected skin.

Changes of the skin barrier and bacterial colonization after hair removal by clipper and by razor

Background: Inappropriate hair removal increases the risk of surgical site infections which are associated with a higher morbidity and mortality of surgical patients. Here, the effects of a clipping device and a disposable razor on the skin barrier, microbial burden and surface structure were compared. Methods: Changes in bacterial colonization, transepidermal water loss, antioxidant status and the skin surface structure were investigated on the calves of 12 healthy volunteers. Measurement time points were at baseline (t base ) and 24 hours after hair removal (t 24 ). Results: Both, the disposable razor and the clipper showed a decrease in log colony-forming units count from t base (mean(t base ) ± standard deviation = 2.6 ± 1.27, median ± standard error = 2.6 ± 0.37) to t 24 at p razo r = 0.05 and p clipper = 0.06 respectively. At t 24 clipping resulted in a higher reduction of log colony-forming units (mean(t 24 ) = 1.76 ± 0.8, median = 1.69 ± 0.23) compared to the use of the disposable razor (mean(t 24 ) = 1.84 ± 0.85, median = 1.91 ± 0.24). Furthermore, the razor-treated group showed an increase in colony-forming units from t 0 to t 24 , whereas clipping lead to a continuous decrease in colony-forming units from t 0 to t 24 . An enhanced appearance of microlesions and a significant increase of transepidermal water loss after shaving using the disposable razor (p = 0.005) were found indicating skin barrier disruptions. Clipping showed no significant effect on transepidermal water loss. Conclusion: Hair removal using the clipping device results in less disruption of the skin barrier compared to the razor, avoiding the development of microlesions. This could be favorable for the prevention of surgical side infections and postoperative wound management.

Protective effect of diet supplemented with rice prolamin extract against DNCB-induced atopic dermatitis in BALB/c mice

BackgroundRice prolamin has been reported to possess antioxidative, anti-inflammatory and immune-promoting properties. This study is aimed to examine the protective effects of dietary rice prolamin extract (RPE) against dinitrochlorobenzene (DNCB)-induced atopic dermatitis (AD)-like skin lesions in mice.MethodsBALB/c mice were fed diet supplemented with 0–0.1 % RPE for 6 weeks. For the last 2 weeks, 1 % or 0.2 % DNCB was applied repeatedly to the back skin of mice to induce AD-like lesions. Following AD induction, the severity of skin lesions was examined macroscopically and histologically. In addition, the serum levels of IgE, IgG1 and IgG2a were determined by ELISA, and the mRNA expression of IL-4 and IFN-γ in the skin was determined by real-time PCR.ResultsDietary RPE suppressed the clinical symptoms of DNCB-induced dermatitis as well as its associated histopathological changes such as epidermal hyperplasia and infiltration of mast cells and eosinophils in the dermis. RPE treatment also suppressed the DNCB-induced increase in transepidermal water loss. Dietary RPE inhibited the DNCB-induced enhancement of serum IgE and IgG1 levels, whereas it increased the serum IgG2a level in DNCB-treated mice. In addition, dietary RPE upregulated the IFN-γ mRNA expression and downregulated the IL-4 mRNA expression in the skin of DNCB-treated mice.ConclusionsThe above results suggest that dietary RPE exerts a protective effect against DNCB-induced AD in mice via upregulation of Th1 immunity and that RPE may be useful for the treatment of AD.

Barrier function and natural moisturizing factor levels after cumulative exposure to a fruit-derived organic acid and a detergent: different outcomes in atopic and healthy skin and relevance for occupational contact dermatitis in the food industry.

Fruit-derived organic compounds and detergents are relevant exposure factors for occupational contact dermatitis in the food industry. Although individuals with atopic dermatitis (AD) are at risk for development of occupational contact dermatitis, there have been no controlled studies on the effects of repeated exposure to multiple irritants, relevant for the food industry, in atopic skin. The aim of the study was to investigate the outcomes of repeated exposure to a fruit-derived organic acid and a detergent in AD compared to healthy volunteers. The volunteers were exposed to 2.0% acetic acid (AcA) and/or 0.5% sodium lauryl sulfate (SLS) in controlled tandem repeated irritation test. The outcomes were assessed by measurements of erythema, transepidermal water loss (TEWL) and natural moisturizing factor (NMF) levels. In the AD volunteers, repeated AcA exposure led to barrier disruption and significant TEWL increase; no significant differences after the same exposure in the healthy controls were found. Repeated exposure to SLS and the irritant tandems enhanced the reactions and resulted in a significantly higher increase in TEWL in the AD compared to the control group. Cumulative irritant exposure reduced the NMF levels in both groups. Differences in the severity of irritant-induced barrier impairment in atopic individuals contribute to the risk for occupational contact dermatitis in result of multiple exposures to food-derived irritants and detergents.

Dietary Milk Sphingomyelin Prevents Disruption of Skin Barrier Function in Hairless Mice after UV-B Irradiation.

Exposure to ultraviolet-B (UV-B) irradiation causes skin barrier defects. Based on earlier findings that milk phospholipids containing high amounts of sphingomyelin (SM) improved the water content of the stratum corneum (SC) in normal mice, here we investigated the effects of dietary milk SM on skin barrier defects induced by a single dose of UV-B irradiation in hairless mice. Nine week old hairless mice were orally administrated SM (146 mg/kg BW/day) for a total of ten days. After seven days of SM administration, the dorsal skin was exposed to a single dose of UV-B (20 mJ/cm2). Administration of SM significantly suppressed an increase in transepidermal water loss and a decrease in SC water content induced by UV-B irradiation. SM supplementation significantly maintained covalently-bound ω-hydroxy ceramide levels and down-regulated mRNA levels of acute inflammation-associated genes, including thymic stromal lymphopoietin, interleukin-1 beta, and interleukin-6. Furthermore, significantly higher levels of loricrin and transglutaminase-3 mRNA were observed in the SM group. Our study shows for the first time that dietary SM modulates epidermal structures, and can help prevent disruption of skin barrier function after UV-B irradiation.