The skin barrier and use of moisturizers in atopic dermatitis

Emerging nanotechnology backed formulations for the management of atopic dermatitis

Atopic dermatitis is a prevalent chronic skin inflammation affecting 2.1 to 4.1% of adults globally. The complexity of its pathogenesis and the relapsing nature make it challenging to treat. Current treatments follow European Academy of Dermatology and Venerology guidelines, but advanced cases with recurring lesions lack effective therapies. To address this gap, researchers are exploring nanotechnology for targeted drug delivery. Nanoparticles offer benefits such as improved drug retention, stability, controlled release and targeted delivery through the disrupted epidermal barrier. This integrated review evaluates the current state of AD treatment and highlights the potential of novel nano-formulations as a promising approach to address the disease.

The immunological and structural epidermal barrier dysfunction and skin microbiome in atopic dermatitis-an update

Atopic dermatitis (AD) is a common, chronic and relapsing inflammatory skin disease with various clinical presentations and combinations of symptoms. The pathophysiology of AD is complex and multifactorial. There are several factors involved in the etiopathogenesis of AD including structural and immunological epidermal barrier defect, imbalance of the skin microbiome, genetic background and environmental factors. Alterations in structural proteins, lipids, proteases, and their inhibitors, lead to the impairment of the stratum corneum which is associated with the increased skin penetration and transepidermal water loss. The elevated serum immunoglobulin E levels and blood eosinophilia have been shown in the majority of AD patients. Type 2 T-helper cell immune pathway with increased expression of interleukin (IL)-4, IL-5, and IL-13, has an important role in the etiopathogenesis of AD. Both T cells and keratinocytes contribute to epidermal barrier impairment in AD via a dynamic interaction of cytokines and chemokines. The skin microbiome is another factor of relevance in the etiopathogenesis of AD. It has been shown that during AD flares, Staphylococcus aureus (S. aureus) colonization increased, while Staphylococcus epidermidis (S. epidermidis) decreased. On the contrary, S. epidermidis and species of Streptococcus, Corynebacterium and Propionibacterium increased during the remision phases. However, it is not clear whether skin dysbiosis is one of the symptoms or one of the causes of AD. There are several therapeutic options, targeting these pathways which play a critical role in the etiopathogenesis of AD. Although topical steroids are the mainstay of the treatment of AD, new biological therapies including IL-4, IL-13, and IL-31 inhibitors, as well as Janus kinase inhibitors (JAKi), increasingly gain more importance with new advances in the therapy of AD. In this review, we summarize the role of immunological and structural epidermal barrier dysfunction, immune abnormalities, impairment of lipids, filaggrin mutation and skin microbiome in the etiopathogenesis of AD, as well as the therapeutic options for AD and their effects on these abnormalities in AD skin.

A systematic review of natural products for skin applications: Targeting inflammation, wound healing, and photo-aging

BACKGROUND

Every day the skin is constantly exposed to several harmful factors that induce oxidative stress. When the cells are incapable to maintain the balance between antioxidant defenses and reactive oxygen species, the skin no longer can keep its integrity and homeostasis. Chronic inflammation, premature skin aging, tissue damage, and immunosuppression are possible consequences induced by sustained exposure to environmental and endogenous reactive oxygen species. Skin immune and non-immune cells together with the microbiome are essential to efficiently trigger skin immune responses to stress. For this reason, an ever-increasing demand for novel molecules capable of modulating immune functions in the skin has risen the level of their development, particularly in the field of natural product-derived molecules.

PURPOSE

In this review, we explore different classes of molecules that showed evidence in modulate skin immune responses, as well as their target receptors and signaling pathways. Moreover, we describe the role of polyphenols, polysaccharides, fatty acids, peptides, and probiotics as possible treatments for skin conditions, including wound healing, infection, inflammation, allergies, and premature skin aging.

METHODS

Literature was searched, analyzed, and collected using databases, including PubMed, Science Direct, and Google Scholar. The search terms used included "Skin", "wound healing", "natural products", "skin microbiome", "immunomodulation", "anti-inflammatory", "antioxidant", "infection", "UV radiation", "polyphenols", "polysaccharides", "fatty acids", "plant oils", "peptides", "antimicrobial peptides", "probiotics", "atopic dermatitis", "psoriasis", "auto-immunity", "dry skin", "aging", etc., and several combinations of these keywords.

RESULTS

Natural products offer different solutions as possible treatments for several skin conditions. Significant antioxidant and anti-inflammatory activities were reported, followed by the ability to modulate immune functions in the skin. Several membrane-bound immune receptors in the skin recognize diverse types of natural-derived molecules, promoting different immune responses that can improve skin conditions.

CONCLUSION

Despite the increasing progress in drug discovery, several limiting factors need future clarification. Understanding the safety, biological activities, and precise mechanisms of action is a priority as well as the characterization of the active compounds responsible for that. This review provides directions for future studies in the development of new molecules with important pharmaceutical and cosmeceutical value.

English version of guidelines for the management of asteatosis 2021 in Japan

This is the English version of guidelines for the management of asteatosis 2021 in Japan. Asteatosis is a synonym of xerosis found in a wide range of diseases that induce dry skin through impaired functions of either water retention of the stratum corneum or skin covering with acid mantle. Patients with asteatosis may be accompanied by pruritus. Moisturizers are the first-line treatment for asteatosis and their adequate use must be recommended. The main purpose of the present guidelines is to define skin symptoms requiring treatment with moisturizers for medical use in patients with asteatosis. If the deterioration of marked scaling or scratch marks is predicted, therapeutic intervention with moisturizers for medical use should be considered even in the absence of pruritus. Regarding six important points requiring decision-making in clinical practice (clinical questions), we evaluated the balance between the benefits and harm of medical interventions in reference to previous reports of clinical research, and presented the recommendation grades and evidence levels to optimize the patient outcome by medical interventions.

Using emollients to promote safe and effective skin care for patients

The role of emollients in the treatment of dry skin conditions is often underestimated. Emollients promote optimal skin health and prevent skin breakdown, and their use can improve patients' quality of life. However, when advising patients on emollient use, nurses must consider the challenges involved such as the extensive choice of products and the necessity of regular applications. This article explores the development of dry skin conditions and outlines the role of emollients in maintaining the skin barrier function. The author also details optimal nursing practice in areas such as emollient prescribing and application.

Beneficial Effects of Antioxidant Furfuryl Palmitate in Non-pharmacologic Treatments (Prescription Emollient Devices, PEDs) for Atopic Dermatitis and Related Skin Disorders

Introduction

Atopic dermatitis (AD) is a common chronic inflammatory skin disease; it requires long-term treatments focused on symptomatic relief. Current first-line treatments include moisturizers and topical corticosteroids. Recently, topical antioxidants have been added to moisturizer formulations to alleviate mild-to-moderate AD. The aim of this review was to evaluate the efficacy and tolerability of furfuryl palmitate, a new antioxidant molecule, and furfuryl derivatives.

Methods

A PubMed/Google Scholar search was conducted using the term “furfuryl palmitate” (and its derivatives, including AR-GG27^®) combined with “skin,” “atopic dermatitis,” and “atopic eczema.” Existing trials including adult and pediatric patients with AD and related skin disorders were evaluated. The treatment indication(s), number of subjects, treatment protocols, results, and side effects were recorded.

Results

Effective treatments with furfuryl palmitate and furfuryl derivatives have been reported for the following conditions: atopic, seborrheic, irritative, and allergic contact dermatitis, eczema, xerosis, and cutaneous inflammatory pathologies. All the products tested showed a good tolerability profile.

Conclusion

Studies performed up to now showed that furfuryl derivatives can efficaciously contrast signs and symptoms of mild-to-moderate AD, erythema, and widespread diffuse cutaneous pathologies in both adult and pediatric patients, representing a real alternative to steroids and a valid aid in the treatment of skin disorders, with no side effects and without requiring precautions in use.

Funding

Relife S.r.l. - Menarini Group.

Plain Language Summary

Plain language summary available for this article.

Heparinoid suppresses Der p-induced IL-1β production by inhibiting ERK and p38 MAPK pathways in keratinocytes

Epidermal keratinocytes initiate skin inflammation by activating immune cells. The skin barrier is disrupted in atopic dermatitis (AD) and epidermal keratinocytes can be exposed to environmental stimuli, such as house dust mite (HDM) allergens. We showed previously that HDM allergens activate the NLRP3 inflammasome of keratinocytes, thereby releasing pro-inflammatory cytokines. Heparinoid is an effective moisturizer for atopic dry skin. However, a recent report showed that heparinoid treatment can improve inflammation of lichen planus. Therefore, we hypothesized that it acts on epidermal keratinocytes not only as a moisturizer, but also as a suppressant of the triggers of skin inflammation. We found that HDM allergen-induced interleukin (IL)-1β release from keratinocytes was inhibited significantly by heparinoid pretreatment without affecting cell viability. However, heparinoid did not affect caspase-1 release, suggesting that heparinoid did not affect HDM allergen-induced inflammasome activation. Heparinoid treatment not only decreased intracellular levels of pro-IL-1β, but also suppressed IL-1β messenger RNA (mRNA) expression in keratinocytes. Among the intracellular signalling pathways, the activation of extracellular signal-regulated kinase and p38 pathways, which are required for IL-1β expression in keratinocytes, was inhibited by heparinoid treatment. The inhibitory effect of heparinoid on IL-1β mRNA expression was also confirmed with living skin equivalents. Our results demonstrated that heparinoid suppresses the initiation of keratinocyte-mediated skin inflammation.

Influence of a Novel Dimeric Ceramide Molecule on the Nanostructure and Thermotropic Phase Behavior of a Stratum Corneum Model Mixture

The stratum corneum (SC) is the outermost layer of the skin and is composed of a multilayered assembly of mostly ceramids (Cer), free fatty acids, cholesterol (Chol), and cholesterol sulfate (Chol-S). Because of the tight packing of these lipids, the SC features unique barrier properties defending the skin from environmental influences. Under pathological conditions, where the skin barrier function is compromised, topical application of molecules that rigidify the SC may lead to a restored barrier function. To this end, molecules are required that incorporate into the SC and bring back the original rigidity of the skin barrier. Here, we investigated the influence of a novel dimeric ceramide (dim-Cer) molecule designed to feature a long, rigid hydrocarbon chain ideally suited to forming an orthorhombic lipid phase. The influence of this molecules on the thermotropic phase behavior of a SC mixture consisting of Cer[AP18] (55 wt %), cholesterol (Chol, 25 wt %), steric acid (SA, 15 wt %), and cholesterol sulfate (Chol-S, 5 wt %) was studied using a combination of neutron diffraction and ²H NMR spectroscopy. These methods provide detailed insights into the packing properties of the lipids in the SC model mixture. Dim-Cer remains in an all-trans state of the membrane-spanning lipid chain at all investigated temperatures, but the influence on the phase behavior of the other lipids in the mixture is marginal. Biophysical experiments are complemented by permeability measurements in model membranes and human skin. The latter, however, indicates that dim-Cer only partially provides the desired effect on membrane permeability, necessitating further optimization of its structure for medical applications.

Novel concepts of prevention and treatment of atopic dermatitis through barrier and immune manipulations with implications for the atopic march

Skin barrier abnormalities have been suggested to play an essential role in initiation of early atopic dermatitis (AD). Antigen penetration through a compromised barrier likely leads to increased innate immune responses, antigen-presenting cell stimulation, and priming of overt cutaneous disease. In a T_H2-promoting environment, T-cell/B-cell interactions occurring in regional lymph nodes lead to excessive IgE switch. Concurrent redistribution of memory T cells into the circulation not only leads to exacerbation of AD through T-cell skin infiltration but also spreads beyond the skin to initiate the atopic march, which includes food allergy, asthma, and allergic rhinitis. Possible primary interventions to prevent AD are focusing on improving skin barrier integrity, including supplementing barrier function with moisturizers. As for secondary prophylaxis in children with established AD, this can be stratified into prevention of disease exacerbations by using proactive approaches (with either topical corticosteroids or topical calcineurin inhibitors) in mild AD cases or the prevention of other atopic disorders that will probably mandate systemic immunosuppression in severe AD cases.

An open-label forearm-controlled pilot study to assess the effect of a proprietary emollient formulation on objective parameters of skin function of eczema-prone individuals over 14 days

Background

This study examines the efficacy of a new plant-based emollient and assesses product acceptability.

Methods

Primary efficacy endpoints were improvement in transepidermal water loss, hydration, skin elasticity and firmness, erythema, and skin roughness and smoothness as measured using the versions of Tewameter, Corneometer, Cutometer, Mexameter, and Visioscan VC98, respectively. The cream was applied twice daily by 32 participants to an area of one forearm unaffected by eczema, while the same area of the other forearm was used as a control. Measurements were taken at day 0 and day 14. Secondary endpoints assessed the acceptability of the product.

Results

At the end of 2 weeks, transepidermal water loss, hydration, skin elasticity and firmness, erythema, and skin roughness and smoothness improved. All changes were statistically significant (p<0.01). The rate of satisfaction with the emollient properties was 82%, and the rate of absorption into the skin was 88%. Results show that the emollient hydrates and repairs eczema-prone skin with high levels of acceptability.

Potential Applications of Phyto-Derived Ceramides in Improving Epidermal Barrier Function

The outer most layer of the skin, the stratum corneum, consists of corneocytes which are coated by a cornified envelope and embedded in a lipid matrix of ordered lamellar structure. It is responsible for the skin barrier function. Ceramides (CERs) are the backbone of the intercellular lipid membranes. Skin diseases such as atopic dermatitis and psoriasis and aged skin are characterized by dysfunctional skin barrier and dryness which are associated with reduced levels of CERs. Previously, the effectiveness of supplementation of synthetic and animal-based CERs in replenishing the depleted natural skin CERs and restoring the skin barrier function have been investigated. Recently, however, the barrier function improving effect of plant-derived CERs has attracted much attention. Phyto-derived CERs (phytoCERs) are preferable due to their assumed higher safety as they are mostly isolated from dietary sources. The beneficial effects of phytoCER-based oral dietary supplements for skin hydration and skin barrier reinforcement have been indicated in several studies involving animal models as well as human subjects. Ingestible dietary supplements containing phytoCERs are also widely available on the market. Nonetheless, little effort has been made to investigate the potential cosmetic applications of topically administered phytoCERs. Therefore, summarizing the foregoing investigations and identifying the gap in the scientific data on plant-derived CERs intended for skin-health benefits are of paramount importance. In this review, an attempt is made to synthesize the information available in the literature regarding the effects of phytoCER-based oral dietary supplements on skin hydration and barrier function with the underlying mechanisms.

Controlled Penetration of a Novel Dimeric Ceramide into and across the Stratum Corneum Using Microemulsions and Various Types of Semisolid Formulations

Ceramides (CERs) are integral parts of the intercellular lipid lamellae of the stratum corneum (SC), which is responsible for the barrier function of the skin. Many skin diseases such as atopic dermatitis and psoriasis are associated with the depletion or disturbance of the level of CERs in the SC. Administration of an exogenous novel dimeric ceramide (dCER) deep into the SC may help to stabilize the SC barrier substantially and to treat some skin disease conditions. Consequently, with the help of the existing technology, it might be possible to formulate various pharmaceutical dosage forms that can facilitate penetration of dCER into the SC. Therefore, the penetration of dCER was studied using a high-performance liquid chromatography/atmospheric-pressure ionization/mass spectrometry method for the detection and quantification of exogenous dCER in the SC as well as other skin layers. Penetration studies were carried out in the Franz diffusion cell using excised human skin ex vivo. Penetration of dCER was studied with 3 model formulations: a colloidal formulation (microemulsion), a cream formulation with ethoxydiglycol as penetration enhancer and a nanoformulation. The highest concentrations of dCER in the different skin layers were found after application of the cream with penetration enhancer. Surprisingly, the lowest concentrations of dCER in the different skin layers were found after application of the microemulsion.

MALDI MSI analysis of lipid changes in living skin equivalents in response to emollient creams containing palmitoylethanolamide

Mass spectrometry imaging (MSI) is a powerful tool for the study of intact tissue sections. The use of matrix-assisted laser desorption/ionisation (MALDI) MSI for the study of the distribution and effect of emollient treatment on sections of reconstructed living skin equivalents during their development and maturation is described. Living skin equivalent (LSE) samples were obtained at 14days development, re-suspended in maintenance medium and incubated for 24h after delivery. The medium was changed, the LSE treated with either Physiogel A.I.® or Oilatum Junior® emollients and then re-incubated and samples taken at 4, 6 and 24h time points. Mass spectra and mass spectral images were recorded from 12μm sections of the LSE taken at each time point for comparison using MALDI mass spectrometry (MS). It was possible to detect ions characteristic of each emollient in the LSE. In addition a number of lipid species previously reported as being significant in the maturation of the LSE were observable. At the 24h time point, the images revealed what appeared to be differences in the organisation of the skin cells observed across the Physiogel A.I.® treatment group tissue sections when directly compared to the untreated tissue group.

Microspectroscopic Confocal Raman and Macroscopic Biophysical Measurements in the in vivo Assessment of the Skin Barrier: Perspective for Dermatology and Cosmetic Sciences

Skin barrier function, confined to the stratum corneum, is traditionally evaluated using established, noninvasive biophysical methods like transepidermal water loss, capacitance and conductance. However, these methods neither measure skin molecular composition nor its structure, hindering the actual causes of skin barrier change or impairment. At the same time, confocal Raman microspectroscopy (CRS) can directly measure skin molecular composition and structure and has proven itself to be a powerful technique for biomolecular analysis. The aims of this literature review were to evaluate noninvasive biophysical methods in view of CRS and to outline a direction towards more specific and informative skin measurement methods. We address this by investigating, for the first time, the relation between in vivo assessment of the skin barrier using indirect biophysical methods and the actual skin composition and structure as given by CRS, and emphasize the high potential of CRS for dermatology and cosmetic sciences. CRS acceptance in these fields will require close collaboration between dermatologists, skin scientists and spectroscopy experts towards simplifying the technology and creating robust, rapid, easy-to-use and less expensive CRS applications.

The Relationship between Solubility and Transdermal Absorption of Tadalafil

PURPOSE

The aim of this study was to find a relationship between drug solubility and its transdermal permeation and find the best vehicle composition to improve transdermal permeation of Tadalafil.

METHODS

Pure or binary mixtures of commonly used solvents in pharmaceutical sciences including ethanol, glycerin, N-methyl pyrrolidone (NMP), polyethylene glycol (PEG) 400 and propylene glycol (PG) were evaluated for drug solubility and transdermal delivery through the exercised rat skin employing Franz diffusion cells.

RESULTS

Tadalafil showed higher solubility in NMP compared to the other solvents. The amount of Tadalafil permeation from the pure vehicles was ranked as follow: Ethanol >glycerin >NMP>PEG 400 >PG. Furthermore, the solubility and transdermal delivery from binary mixtures of NMP and PG were higher than that obtained from pure PG, and accordingly, both increased with increasing NMP concentration in the binary solvent mixtures. The Flux values were determined as following order for Ethanol>NMP>glycerin>PG>PEG 400.

CONCLUSION

Generally, increase in Tadalafil solubility resulted in a decrease in its skin penetration rate and amount. However, NMP exhibited substantial drug skin penetration rate and amount accompanying with appropriate drug solvency. In conclusion, the results of this study introduced NMP as a solvent suitable for application in the formulation of topically applied drug delivery systems.

Skin diseases associated with the depletion of stratum corneum lipids and stratum corneum lipid substitution therapy

The skin is the largest organ of the body, whose main function is to protect the body against the loss of physiologically important components as well as harmful environmental insults. From the inside to the outside, the skin comprises three major structural layers: the hypodermis, the dermis and the epidermis. The epidermis contains four different sublayers, the stratum corneum (SC), stratum granulosum, stratum spinosum and stratum basale, where the barrier function of the skin mainly lies in the outermost layer of the epidermis, the SC. The SC contains corneocytes that are embedded in a lipid matrix existing in the form of lipid bilayers. The lipid bilayers are formed mainly from ceramides, free fatty acids and cholesterol, constitute the only continuous pathway across the SC and are responsible for the barrier function of the skin. However, the depletion or disturbance of SC lipids in the SC leads to a perturbation of the barrier function of the skin, and, conversely, several skin diseases such as psoriasis and atopic dermatitis are associated with the depletion of these SC lipids. Therefore, it is of paramount importance to understand the interrelationship between the depletion of SC lipids and skin diseases as well as factors that affect the composition and organization of SC lipids in order to assess the potential benefit of a direct replacement of the missing SC lipids as a means of treating affected, aged or diseased skin.

Controlled penetration of ceramides into and across the stratum corneum using various types of microemulsions and formulation associated toxicity studies

Several skin diseases such as psoriasis and atopic dermatitis are associated with the depletion or disturbance of stratum corneum (SC) lipids such as ceramides (CERs), free fatty acids and cholesterol. Studies suggested that replenishment of these lipids might help to treat diseased, affected or aged skin. With this premises in mind, there are some formulations in the market that contain SC lipids and currently, to facilitate permeation of the lipids deep into the SC, various CERs, and other SC lipid microemulsions (MEs) were developed and characterised using lecithin or TEGO® CARE PL 4 (TCPL4) as base surfactants. However, to date, there are no reports that involve the permeability of SC lipids into and across the SC, and therefore, the penetration of CER [NP] as a model ceramide from various formulations was investigated ex vivo using Franz diffusion cell. Besides, the toxicity of the MEs was assessed using hen's egg test chorioallantoic membrane (HET-CAM). The results of the study showed that CER [NP] could not permeate into deeper layers of the SC from a conventional hydrophilic cream. Unlike the cream, CER [NP] permeated into the deeper layers of the SC from both type of MEs, where permeation of the CER was more and into deeper layers from droplet type and lecithin-based MEs than bicontinuous (BC) type and TCPL4 based MEs, respectively. The CER also permeated into deeper layers from ME gels which was, however, shallow and to a lesser extent when compared with the MEs. The results of HET-CAM showed that both MEs are safe to be used topically, with lecithin-based MEs exhibiting better safety profiles than TCPL4 based MEs. Concluding, the study showed that the MEs are safe to be used on the skin for the controlled penetration of CER [NP] deep into the SC.

Lecithin-based microemulsions for targeted delivery of ceramide AP into the stratum corneum: formulation, characterizations, and in vitro release and penetration studies

PURPOSE

To improve the solubility and penetration of Ceramide AP (CER [AP]) into the stratum corneum that potentially restores the barrier function of aged and affected skin.

METHODS

CER [AP] microemulsions (MEs) were formulated using lecithin, Miglyol® 812 (miglyol) and water-1,2 pentandiol (PeG) mixture as amphiphilic, oily and hydrophilic components, respectively. The nanostructure of the MEs was revealed using electrical conductivity, differential scanning calorimeter (DSC) and electron paramagnetic resonance (EPR) techniques. Photon correlation spectroscopy (PCS) was used to measure the sizes and shape of ME droplets. The release and penetration of the CER into the stratum corneum was investigated in vitro using a multi-layer membrane model.

RESULTS

The MEs exhibited excellent thermodynamic stability (>2 years) and loading capacity (0.5% CER [AP]). The pseudo-ternary phase diagrams of the MEs were obtained and PCS results showed that the droplets are spherical in shape and bigger in size. In vitro investigations showed that the MEs exhibited excellent rate and extent of release and penetration.

CONCLUSIONS

Stable lecithin-based CER [AP] MEs that significantly enhance the solubility and penetration of CER [AP] into the stratum corneum were developed. The MEs also have better properties than the previously reported polyglycerol fatty acid surfactant-based CER [AP] MEs.

Objective and subjective in vivo comparison of two emollient products

Background

Few studies have directly compared the effectiveness of different emollients in vivo, and the important matter of patient preference is generally overlooked.

Methods

We report the results of an assessor-blinded, bilateral, concurrent comparison of two emollient pharmaceutical presentations, ie, Doublebase gel (DB) and Aqueous cream BP (AC), applied by 20 participants three times daily for 7 consecutive days. The primary efficacy endpoint was cumulative improvement in skin hydration measured by corneometry on days 1, 3, and 5 immediately before the first application and approximately 2 hours after the third application of the day. Secondary endpoints were investigator assessment of skin condition at these time points and participant assessment of product acceptability at the end of the study.

Results

Both products increased skin hydration, but the effect of AC was relatively modest, with morning values readily returning to pretreatment levels. Hydration levels were higher for DB gel, maintained at all time points, and showed stepwise, cumulative increases over the 7 days of use. Overall patient satisfaction scores were higher for DB gel, and especially for “consistency,” “ease of use,” and “ease of absorption into the skin.” Eighty-five percent of participants expressed a desire to use DB gel again as compared with 40% for AC.

Barrier-restoring therapies in atopic dermatitis: current approaches and future perspectives

Atopic dermatitis is a multifactorial, chronic relapsing, inflammatory disease, characterized by xerosis, eczematous lesions, and pruritus. The latter usually leads to an “itch-scratch” cycle that may compromise the epidermal barrier. Skin barrier abnormalities in atopic dermatitis may result from mutations in the gene encoding for filaggrin, which plays an important role in the formation of cornified cytosol. Barrier abnormalities render the skin more permeable to irritants, allergens, and microorganisms. Treatment of atopic dermatitis must be directed to control the itching, suppress the inflammation, and restore the skin barrier. Emollients, both creams and ointments, improve the barrier function of stratum corneum by providing it with water and lipids. Studies on atopic dermatitis and barrier repair treatment show that adequate lipid replacement therapy reduces the inflammation and restores epidermal function. Efforts directed to develop immunomodulators that interfere with cytokine-induced skin barrier dysfunction, provide a promising strategy for treatment of atopic dermatitis. Moreover, an impressive proliferation of more than 80 clinical studies focusing on topical treatments in atopic dermatitis led to growing expectations for better therapies.

Polyglycerol fatty acid ester surfactant-based microemulsions for targeted delivery of ceramide AP into the stratum corneum: formulation, characterisation, in vitro release and penetration investigation

Ceramide AP (CER [AP]) is an integral component of the stratum corneum (SC) lipid matrix and is capable of forming tough and super stable lamellae. It may help to restore the barrier function in aged and affected skin. However, its effectiveness from conventional dosage forms is limited due to its poor solubility and penetration into the SC. Therefore, stable polyglycerol fatty acid ester surfactant (SAA)-based CER [AP] microemulsions (MEs) were formulated and characterised to enhance its solubilisation and penetration into the SC. TEGO® CARE PL 4 (TCPL4: polyglycerol-4-laurate), isopropyl palmitate (IPP) and water-1, 2 pentandiol (PeG) were used as amphiphilic, oily and hydrophilic components, respectively. The effects of HYDRIOL® PGMO.4 (HPGMO4: polyglyceryl-4-oleate) as a co-surfactant (co-SAA) and linoleic acid (Lin A) as part of the oil component on the stability and characteristics of the MEs were investigated. EPR results were used for the first time to reveal MEs nanostructures. The release and penetration behaviour of the MEs was assessed in vitro by using a multi-layer membrane model. The results obtained showed that HPGMO4 and Lin A increased stability and expanded the ME region considerably. The formulations were stable for 10 to >24 months. Dynamic light scattering (DLS) results showed that the droplets were bigger and asymmetric, which might be helpful to localise the CER into the upper layers of the epidermis. Release and penetration from the MEs was superior as compared to the hydrophilic cream (DAB). The rate and extent of CER [AP] released and penetrated from O/W MEs was better than W/O MEs.

Chitosan: antimicrobial action upon staphylococci after impregnation onto cotton fabric

BACKGROUND

High levels of viable Staphylococcus aureus, which are often found on inflamed skin surfaces, are usually associated with atopic dermatitis. Textiles, owing to their high specific surface area and intrinsic hydrophilicity, retain moisture while also providing excellent environmental conditions for microbial growth and proliferation. Recently, a number of chemicals have been added to textiles, so as to confer antimicrobial activity.

AIMS

To evaluate the antimicrobial action of chitosan upon selected skin staphylococci.

METHODS AND RESULTS

We isolated staphylococci from normal skin of 24 volunteers and studied their survival upon contact with chitosan-impregnated cotton fabric. Low and high molecular weight chitosans were used at two concentrations; all four did effectively reduce the growth of some staphylococci (namely Staph. aureus), by up to 5 log cycles, thus unfolding a potential towards control and even prevention of related skin disorders.

CONCLUSION

Our data suggest an effective, but selective antibacterial action of chitosans towards skin bacteria.

SIGNIFICANCE AND IMPACT OF THE STUDY

The possibility to use a natural biopolymer incorporated in a textile to alleviate and even treat some of the symptoms associated with this skin condition may raise an alternative to existing medical treatments. The selectivity observed prevents full elimination of bacteria from the skin surface, which is an advantage.

Topical fluticasone propionate: intervention and maintenance treatment options of atopic dermatitis based on a high therapeutic index

Fluticasone propionate (FP), a medium potent glucocorticoid (class III) of carbothioate nature with a favourable benefit/risk ratio, has emerged as a standard medication for the topical treatment of inflammatory skin disorders, in particular atopic dermatitis (AD). FP is available as a 0.05% cream and a 0.005% ointment formulation. The glucocorticoid is characterized by high lipophilicity, high affinity binding to the glucocorticoid receptor and a rapid hepatic biotransformation. Though skin blanching following topical application of FP surpasses that given with glucocorticoids of medium strength, clinical trials show a low potential of FP for local and systemic adverse effects. Even in paediatric patients with AD as well as in difficult-to-treat areas like face, eyelids and intertriginous areas, FP proved to be both effective and safe. Thus, the therapeutic effects of FP clearly outweigh the unwanted effects. Correspondingly, a therapeutic index of 2.0 can be attributed to this glucocorticoid. In this respect, topical FP does not differ from other topical glucocorticoids with increased benefit-to-risk ratio, e.g. prednicarbate, methylprednisolone aceponate and mometasone furoate. However, randomized controlled trials do not only support conventional intervention but also innovative maintenance treatment.

Formation and stability of oil-in-water nanoemulsions containing rice bran oil: in vitro and in vivo assessments

BACKGROUND

Nanoemulsions have practical application in a multitude of commercial areas, such as the chemical, pharmaceutical and cosmetic industries. Cosmetic industries use rice bran oil in sunscreen formulations, anti ageing products and in treatments for skin diseases. The aim of this study was to create rice bran oil nanoemulsions using low energy emulsification methods and to evaluate their physical stability, irritation potential and moisturising activity on volunteers with normal and diseased skin types.

RESULTS

The nanoemulsion developed by this phase diagram method was composed of 10% rice bran oil, 10% surfactants sorbitan oleate/PEG-30 castor oil, 0.05% antioxidant and 0.50% preservatives formulated in distilled water. The nanoemulsion was stable over the time course of this study. In vitro assays showed that this formulation has a low irritation potential, and when applied to human skin during in vivo studies, the nanoemulsion improved the skin's moisture and maintained normal skin pH values.

CONCLUSION

The results of irritation potential studies and in vivo assessments indicate that this nanoemulsion has potential to be a useful tool to treat skin diseases, such as atopic dermatitis and psoriasis.

Do early skin care practices alter the risk of atopic dermatitis? A case-control study

The rise in atopic dermatitis prevalence observed in industrialized countries is unexplained. We hypothesized that certain skin care practices early in life may increase the risk for developing atopic dermatitis. Our case-control study could not identify any one practice that increased the odds of developing atopic dermatitis, but it revealed that regular lotion use was very common in infants who later develop atopic dermatitis.

A new moisturizer containing physiologic lipid granules alleviates atopic dermatitis

BACKGROUND

Patients with atopic dermatitis show a defective barrier function. In atopic skin, ceramide is significantly decreased and the secretion of lamellar bodies is also impaired. To mimic lamellar bodies, we prepared lipid granules composed of ceramide, fatty acids and cholesterol. Because these lipid granules contain multiple lamellar structures, it is expected that they will have superior affinity to skin; hence, they should have a good moisturizing effect. This study was performed to evaluate the effects of moisturizer containing lipid granules on atopic dermatitis.

METHODS

Patients with mild atopic dermatitis (n = 30, aged 5-19 years) were recruited and instructed to apply a moisturizer containing physiologic lipid granules for 4 weeks. The SCORing Atopic Dermatitis (SCORAD) score and general symptoms were evaluated. In addition, transepidermal water loss (TEWL) and stratum corneum (SC) hydration were also measured.

RESULTS

Twenty-nine patients completed the study. The SCORAD value decreased dramatically after 4 weeks of moisturizer application (p = 0.000). The general symptoms of atopic dermatitis were also greatly improved. At baseline, most patients reported their symptoms as mild and moderate, but after 4 weeks 20 of the patients (69%) had no symptoms. The TEWL was not changed, but the SC hydration increased significantly (p = 0.000). No significant adverse effects were observed.

CONCLUSIONS

Moisturizer containing lipid granules effectively controlled atopic dermatitis.

A pilot study of emollient therapy for the primary prevention of atopic dermatitis

BACKGROUND

Prevention strategies in atopic dermatitis (AD) using allergen avoidance have not been consistently effective. New research reveals the importance of the skin barrier in the development of AD and possibly food allergy and asthma. Correcting skin barrier defects from birth may prevent AD onset or moderate disease severity.

OBJECTIVE

We sought to determine the feasibility of skin barrier protection as a novel AD prevention strategy.

METHODS

We enrolled 22 neonates at high risk for developing AD in a feasibility pilot study using emollient therapy from birth.

RESULTS

No intervention-related adverse events occurred in our cohort followed up for a mean time of 547 days. Of the 20 subjects who remained in the study, 3 (15.0%) developed AD, suggesting a protective effect when compared with historical controls. Skin barrier measurements remained within ranges seen in normal-appearing skin.

LIMITATIONS

No conclusions regarding efficacy can be made without a control group.

CONCLUSIONS

Skin barrier repair from birth represents a novel and feasible approach to AD prevention. Further studies are warranted to determine the efficacy of this approach.

Atopic dermatitis: a review of topical treatment options

BACKGROUND

Atopic dermatitis (AD) is a chronic, pruritic, inflammatory skin disease with a wide range of severity, and is usually the first manifestation of atopic disease. It is one of the most common skin disorders in developed countries, affecting approximately 20% of children and 1-3% of adults. Symptoms such as eczematous papules, plaques, and itch, and their associated consequences, such as sleep disturbance, can significantly impact the quality of life of the patient and family.

SCOPE

This is a broad-based review focusing on clinical practice for primary care physicians treating patients with AD. The PubMed database was searched (to 1 November 2008) for English-language articles containing the keywords atopic dermatitis, atopic eczema, topical calcineurin inhibitor, tacrolimus, pimecrolimus, or corticosteroid. Articles focusing on clinical practice for patients with AD were chosen for further review. A limitation is that this is not a systematic review of the literature.

FINDINGS

Emollients have long been used to maintain the skin barrier function in patients with AD. Topical corticosteroids have been the pillar of medicated therapy for AD since their introduction nearly 50 years ago. The introduction of topical calcineurin inhibitors more than 8 years ago represented the first new class of medication approved for the treatment of AD since topical corticosteroids. Topical calcineurin inhibitors provide targeted anti-inflammatory activity without the local or systemic side-effects seen with topical corticosteroids. More recently, three new, nonsteroidal, barrier creams (Atopiclair * , Mimyx dagger , and Epiceram double dagger ) have entered the marketplace for AD treatment. A multi-therapeutic approach that incorporates short-term management of flares and longer-term strategies to prolong the time between flares is needed for the treatment of AD.

CONCLUSION

Multiple topical therapies have been successfully used to treat patients with AD. An understanding of the available treatment options will help primary care providers striving to achieve best practice in the management of AD.

Mapping of the dog skin based on biophysical measurements

Trans epidermal water loss (TEWL), skin hydration status and pH were determined in 14 skin regions of five healthy male Beagle dogs (2-4 years) both before and after anaesthesia. Trans epidermal water loss was highest for the footpad and head and lowest for the inguinal region. Skin hydration status was higher in the ear but did not vary significantly in other regions. Skin pH was usually alkaline with the highest values on the lower back and tail. Following anaesthesia, TEWL and skin hydration were significantly lower on the head, upper back and footpad, and upper back and elbow respectively, while skin pH was unaffected by this procedure. While measurement of pH would seem to be valid anywhere on the body in anaesthetized dogs, regional factors should be considered when interpreting TEWL and skin hydration values and when treating regional skin diseases in veterinary practice.

Topical delivery of interleukin-13 antisense oligonucleotides with cationic elastic liposome for the treatment of atopic dermatitis

BACKGROUND

Interleukin (IL)-13, overproduced in the skin of atopic dermatitis (AD), has been shown to play an essential role in the pathogenesis of the disease. Thus, inhibition of IL-13 production should provide a key step to alleviate disease conditions of the atopic skin. In the present study, IL-13 antisense oligonucleotide (ASO) was designed and formulated with cationic elastic liposome (cEL) to improve transdermal delivery.

METHODS

ASOs were generated against murine IL-13 mRNA (+4 to + 23) and complexed with cEL. Physicochemical properties of IL-13 ASO/cEL complex were examined by DNA retardation and DNase I protection assay. An in vitro inhibition study was performed in T-helper 2 (Th2) cells and cytotoxicity was tested by the XTT assay. The in vivo effect of IL-13 ASO/cEL complex was tested in a murine model of AD.

RESULTS

In vitro, the IL-13 ASO/cEL complex showed dose- and ratio-dependent inhibition of IL-13 secretion in Th2 cells. At the IL-13 ASO/cEL ratio of 6, maximum inhibition of IL-13 secretion was observed. When applied to the ovalbumin-sensitized murine model of AD, topically administered IL-13 ASO/cEL complex dramatically suppressed IL-13 production (by up to 70% of the control) in the affected skin region. In addition, the levels of IL-4 and IL-5 were also significantly reduced. Moreover, IL-13 ASO/cEL-treated AD mice showed reduced infiltration of inflammatory cells into the epidermal and dermal areas, with concomitant reduction of skin thickness.

CONCLUSIONS

These data suggests that IL-13 ASO/cEL complex can provide a potential therapeutic tool for the treatment of AD and also be applied to other immune diseases associated with the production of Il-13.

The multifunctional role of ectoine as a natural cell protectant

The protective properties of ectoine, formerly described for only extremophilic microorganisms, can be transferred to human skin. Our present data show that the compatible solute ectoine protects the cellular membrane from damage caused by surfactants. Transepidermal water loss measurements in vivo suggest that the barrier function of the skin is strengthened after the topical application of an oil in water emulsion containing ectoine. Ectoine functions as a superior moisturizer with long-term efficacy. These findings indicating that ectoine is a strong water structure-forming solute are explained in silico by means of molecular dynamic simulations. Spherical clusters containing (1) water, (2) water with ectoine, and (3) water with glycerol are created as model systems. The stronger the water-binding activity of the solute, the greater the quantity of water molecules remaining in the cluster at high temperatures. Water clusters around ectoine molecules remain stable for a long period of time, whereas mixtures of water and glycerol break down and water molecules diffuse out of the spheres. On the basis of these findings, we suggest that the hydrogen bond properties of solutes are not solely responsible for maintaining the water structure form. Moreover, the particular electrostatic potential of ectoine as an amphoteric molecule with zwitterionic character is the major cause for its strong affinity to water. Because of its outstanding water-binding activity, ectoine might be especially useful in preventing water loss in dry atopic skin and in recovering skin viability and preventing skin aging.

Emollient, humectant, and fluorescent alpha,beta-unsaturated thiol esters for long-acting skin applications

We describe compounds in which an emollient or a humectant bears an alpha,beta-unsaturated thiol ester capable of reacting with nucleophilic amino acids in stratum corneum proteins. These compounds should serve as long-lasting moisturizers for skin. The emollient derivatized was octadecyl propanoate, and the humectant was poly(ethylene glycol). These hydrophobic and hydrophilic compounds, as well as a fluorescent, dansyl-containing thiol ester, were found to react within minutes with the thiol N-acetylcysteamine upon addition of a catalytic amount of an organic base in chloroform. The structures of the products resulting from conjugate addition to the unsaturated thiol esters were determined by NMR spectroscopy. In the case of the alpha,beta,gamma,delta-unsaturated (sorboyl) thiol ester, both the 1,4-addition product and the beta,gamma-unsaturated-1,6-addition product formed, followed by diadduct. An in vivo test of the fluorescent alpha,beta-unsaturated thiol ester showed that this compound persisted on skin for 3 weeks vs. 6 days for the non-bonding control compound.

The Steroid-Sparing Effect of an Emollient Therapy in Infants with Atopic Dermatitis: A Randomized Controlled Study

BACKGROUND

No study has clearly demonstrated the steroid-sparing effect of emollients in the treatment of atopic dermatitis (AD).

AIM

Evaluating the effect of an emollient containing oat extracts on the amount of topical corticosteroids used in infants with moderate to severe AD.

STUDY DESIGN

During 6 weeks, 173 infants under 12 months old treated for inflammatory lesions by moderate- and/or high-potency topical corticosteroids randomly received the emollient or not (control group).

METHODS

Evaluation of corticosteroid consumption by weighing the tubes, disease severity by the Scoring Atopic Dermatitis Index (SCORAD), and infants' and parents' quality of life by Infant's Dermatitis Quality of Life Index and Dermatitis Family Impact scores at D0, D21 and D42.

RESULTS

Compared to the control group, the amount of moderate- and high-potency corticosteroids used in 6 weeks decreased by 7.5% (not significant) and 42% (p < 0.05), respectively, in the emollient group. The SCORAD index, and infants' and parents' quality of life significantly improved (p < 0.0001) in both groups.

CONCLUSION

The emollient treatment significantly reduced the high-potency topical corticosteroid consumption in infants with AD.

Increased expression of aquaporin 3 in atopic eczema

BACKGROUND

Dry skin in atopic eczema depends on increased water loss. The mechanisms behind this are poorly understood. The aim of this work was to identify genes that may contribute to water loss in eczema.

METHODS

Affymetrix DNA microarrays U133A were used to analyse gene expression in skin biopsies from 10 patients with atopic eczema and 10 healthy controls.

RESULTS

DNA microarray analysis showed up-regulation of 262 genes and down-regulation of 129 genes in atopic eczema. The known functions of these genes were analysed using Gene Ontology to identify genes that could contribute to increased water loss. This led to identification of aquaporin 3 (AQP3), which has a key role in hydrating healthy epidermis. Increased expression of AQP3 was found in eczema compared with healthy skin. This was confirmed with real-time polymerase chain reaction (P<0.001). In healthy skin, epidermal AQP3 immunoreactivity was weak and mainly found in the stratum basale. A gradient was formed with decreasing AQP3 staining in the lower layers of the stratum spinosum. By contrast, in acute and chronic atopic eczema strong AQP3 staining was found in both the stratum basale and the stratum spinosum.

CONCLUSIONS

Aquaporin 3 is the predominant aquaporin in human skin. Increased expression and altered cellular distribution of AQP3 is found in eczema and this may contribute to water loss.

Tacrolimus ointment 0.03% is safe and effective for the treatment of mild to moderate atopic dermatitis in pediatric patients: results from a randomized, double-blind, vehicle-controlled study

OBJECTIVE

This study was designed to compare the safety and efficacy of tacrolimus ointment 0.03% with vehicle ointment for the treatment of mild to moderate atopic dermatitis (AD) in pediatric patients.

METHODS

A total of 317 patients (2-15 years of age) with mild to moderate AD were randomized to receive tacrolimus ointment or vehicle ointment twice daily in a 6-week, multicenter, double-blind study. Efficacy evaluations, including the Investigators' Global Atopic Dermatitis Assessment, eczema area and severity index, percentage of total body surface area affected, and patient assessment of itch occurred at baseline, day 4, and weeks 2, 4, and 6. Cutaneous adverse events were recorded to evaluate safety.

RESULTS

At the end of study, 50.6% (80 of 158) of the patients were treated successfully with tacrolimus ointment based on Investigators' Global Atopic Dermatitis Assessment scores, a significant improvement compared with patients treated with vehicle ointment (25.8% [41 of 159]). The percent improvement from baseline in eczema area and severity index scores was also significantly greater in tacrolimus-treated patients (54.8%) compared with vehicle-treated patients (20.8%). There was also a significant improvement in the percentage of total body surface area affected of tacrolimus-treated patients (50.5% reduction from baseline) compared with vehicle-treated patients (16.4%). Patient itch scores were significantly lower in tacrolimus-treated patients (2.1) versus vehicle-treated patients (3.7). Overall, the incidence of cutaneous adverse events reported was similar for both treatment groups. There was no significant difference in the incidence of burning or stinging between treatment groups. Significantly fewer tacrolimus-treated patients prematurely discontinued from the study because of a cutaneous adverse event in the treatment area or experienced increased itching and erythema at the application site.

CONCLUSION

Monotherapy with tacrolimus ointment 0.03% is a safe and effective treatment alternative for pediatric patients with mild to moderate AD.

Ceramide analogue 14S24 ((S)-2-tetracosanoylamino-3-hydroxypropionic acid tetradecyl ester) is effective in skin barrier repair in vitro

Stratum corneum ceramides are fundamental for maintaining the skin barrier properties. Their content is decreased in some skin diseases, e.g. atopic dermatitis, and ceramide supplementation is one of the therapeutic approaches. In the present study we have designed novel ceramide analogue 14S24 ((S)-2-tetracosanoylamino-3-hydroxypropionic acid tetradecyl ester) as a potential barrier-repairing agent. We report a convenient two-step synthesis of this analogue with high yields. The ability of 14S24 to repair the disturbed skin barrier was evaluated in vitro on the porcine skin. After 2h application of 14S24 on the skin disrupted by lipid extraction, the permeability decreased significantly almost to the values of the native skin. The compound is effective in 0.1% aqueous suspension and its effect is comparable with physiological skin lipids under the same condition. The comparison of 14S24 and skin ceramides was made via computer modelling and the in silico physico-chemical parameters are reported. We suggest that allylic hydroxyl, that is essential for the apoptogenic activity of ceramides, is not a necessary component of the skin barrier-forming ceramides. The main result of this study is to demonstrate that simpler and easier-to-synthesise ceramide analogues could be effective in the skin barrier repair.

Cleansing, moisturizing, and sun-protection regimens for normal skin, self-perceived sensitive skin, and dermatologist-assessed sensitive skin

Acquiring or maintaining healthy skin requires a multifunctional approach: mild cleansing, moisturizing, and sun protection. The clinical benefits of a daily, healthy facial skin-care regimen comprising a mild cleanser and moisturizer were evaluated on normal skin, self-perceived sensitive skin, and dermatologist-assessed sensitive skin for a period of up to 4 weeks. Subjects with normal, healthy skin were photographed with a calibrated, high-resolution digital camera, and the average improvement in overall health was calculated using image morphing and facial averaging techniques, following a 2-week period of product application. In a second study that included subjects with self-assessed sensitive facial skin, changes in skin hydration, skin dryness, and skin sensitivity (determined by means of a lactic acid sting test and subject self-assessment) were monitored during a 3-week regimen of mild cleansing and moisturizing with products designed for sensitive skin. The third study involved dermatologist-assessed highly sensitive skin patients (mostly rosacea with an atopic background in some cases). These patients underwent a 4-week skin-care regimen involving mild cleansing and moisturizing. In all three studies, significant improvements in skin health/quality were observed by means of expert assessments, instrumental evaluations, and subjective self-assessment.