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Olanexidine gluconate-containing preoperative antiseptic (OLG-C) is colorless, which makes it difficult to determine its area of application. To overcome this drawback, we realized a stable orange-tinted antiseptic (OLG-T) by adding new additives to OLG-C and investigated its pharmaceutical properties compared with OLG-C and povidone iodine (PVP-I). We evaluated the influence of the additives on the antimicrobial activity and adhesiveness of medical adhesives to OLG-T-applied skin by in vitro time-kill/ex vivo micropig skin assays and a peel test using excised micropig skin, respectively. In the in vitro time-kill assay, the bactericidal/fungicidal activity of OLG-T and OLG-C were equivalent. In the ex vivo micropig skin assay, their fast-acting and persistent bactericidal activities against vancomycin-resistant Enterococcus faecalis were higher than that of PVP-I. In the peel test, the adhesion force of the incise drape and the amount of stripped corneocytes on the peeled drape were comparable between OLG-T- and OLG-C-applied skin, but both were less than those of PVP-I-applied skin. The drapes for OLG-T- and OLG-C-applied skin had moderate adhesion force, and the drape-related injuries were expected to be weak. These results suggest that OLG-T performs no worse than OLG-C in terms of its antimicrobial activity and medical adhesive compatibility. Therefore, we expect OLG-T to lead to more convenient preoperative skin preparation and further contribute to lowering surgical site infection rates.

The barrier function of the skin is mainly assured by its outermost layer, stratum corneum (SC), which consists of dead keratin-filled cells embedded in a lipid matrix. The skin is daily exposed to an environment with changing conditions in terms of hydration and different chemicals. Here we investigate how a molecule that has reasonable solubility in both hydrophobic and hydrophilic environments can be directed to certain regions in SC by changing the skin hydration. We use 1,2,3-trimethoxy propane (TMP) as a model substance and solid-state NMR on natural abundance 13C to obtain atomically resolved information on the molecular dynamics of TMP as well as SC lipid and protein components at varying hydration conditions. Upon dehydration, TMP redistributes from the hydrophilic corneocytes to the hydrophobic SC lipid regions. In this way, TMP can act to prevent the fluid–solid lipid transition in drying conditions and be present in the corneocytes in more humid conditions. Hydration can thereby be used as a switch to control the location and action of TMP or similar compounds in complex materials like SC. The general principles described here can also have impact on other applications including lipid-based formulations in food, drug delivery and cosmetics.

Marek Haftek MD, PhD, Maeve A McAleer MB PhD, Ivone Jakasa PhD, WH Irwin McLean PhD DSc. Sanja Kezic PhD, Alan D. Irvine MD DSc

• Enables low-cost simplified system for HS-AFM imaging. • Sinusoidal scanning motion eliminates unwanted scanner oscillation. • Achieving 5,093 µm/s tip-sample velocity with a constant-height DC mode. • A wide imaging area of 46.3×46.3 µm2 with 512×512 pixel resolution. • Open-source LabView code as a foundation for different applications. • High-speed corneocyte nanotextures imaging for skin barrier function assessments.

Oxidative stress is considered a prime contributor to skin aging. Aged skin can be characterized by increased wrinkles and dry and dull appearance, which are associated with increased collagen degradation and inadequate desquamation, respectively. We investigated the antioxidant and skin anti-aging effects of a Ginkgo biloba leaf extract (GLE), an aqueous ethanol extract of Ginkgo biloba leaves, and the molecular mechanisms involved, using HaCaT keratinocytes. HaCaT cells were pretreated with GLE (0–15 μg/mL) and then treated with H2O2 (0.2 mM), and the cell viability and metalloproteinase 1 (MMP-1) protein level were measured. To investigate the mechanisms underlying the GLE’s effects, the cells were incubated with GLE, and then glutathione content, cell migration rate, and the levels of proteins, i.e., MMPs, Kallikrein-related peptidases (KLKs), nuclear factor erythroid 2-related factor 2 (Nrf2), heme oxygenase 1 (HO-1), and mitogen-activated protein kinases, were measured. GLE pretreatment caused decreases in cytotoxicity and the level of MMP-1, a key enzyme that degrades collagen in dermis, induced by H2O2 in HaCaT cells. GLE (5–15 μg/mL) caused increases in glutathione content and HO-1 level in cells, which appeared to be associated with the increase in Nrf2, a principal transcription factor for the antioxidant response. GLE also increased keratinocyte migration, which might result from the increase in KLK-7, a key enzyme that degrades corneodesmosomes and thus stimulates desquamation of corneocytes in epidermis. GLE increased the phosphorylation of c-Jun N-terminal protein kinase and extracellular signal-regulated kinase, which might contribute to the antioxidant and skin anti-aging effects of GLE demonstrated in our results. Our results suggest that GLE may have skin anti-aging effects by protecting keratinocytes against excessive oxidative stress via stimulation of antioxidant response, reducing wrinkle formation via a decrease in MMP-1 expression, and stimulating desquamation via an increase in KLK-7 expression.

The beak or rhamphotheca in turtles is a horny lamina that replaces the teeth. Its origin, development, structure, and protein composition are here presented. At mid-development stages, the epidermis of the maxilla and mandible gives rise to placodes that enlarge and merge into laminae through an intense cell proliferation. In these expanding laminae, the epidermis gives rise to 5-8 layers of embryonic epidermis where coarse filaments accumulate for the initial keratinization of cells destined to be sloughed before hatching. Underneath the embryonic epidermis of the beak numerous layers of spindle-shaped beta-cells are produced while they are absent in other skin regions. Beta-cells contain hard corneous material and give rise to the corneous layer of the beak whose external layers desquamate due to wearing and mechanical abrasion. Beta-catenin is present in nuclei of proliferating keratinocytes of the germinal layer likely responding to a wnt signal, but also is part of the adhesive junctions located among beak keratinocytes. The thick corneous layer is made of mature corneocytes connected one to another along their irregular perimeter by an unknown cementing material and junctional remnants. Immunolabeling shows that the main components of the horny beak are Corneous Beta Proteins (CBPs) of 10-15 kDa which genes are located in the Epidermal Differentiation Complex (EDC) of the turtle genome. Specific CBPs, in addition to a lower amount of Intermediate Filament Keratins, accumulate in the horny beak. Compaction of the main proteins with other unknown, minor proteins give rise to the hard corneous material of the beak.

The development of dry skin is a complex process, with a wide variety of factors each playing different roles in its evolution. Given this, it is important when designing a formulation to tackle dry skin that these varied aspects of skin behaviour are addressed. Presented here are the results of a 3-week moisturization study carried out on dry legs. A wide range of traditional and more recently developed biophysical measurement methods have been combined with visual assessment of skin condition to enable multiple aspects of skin function to be determined. The observed changes in the skin are discussed in terms of the ingredients used in the moisturizing formulation.A range of novel and traditional skin assessment methods and techniques were used to assess the effects of an oil in water-based moisturizing product compared to an untreated site during a 3-week in vivo study on dry lower leg skin.Statistically significant improvements were observed in a range of skin parameters as a result of product usage. Skin hydration assessed using Corneometer®, Epsilon® and visual dry skin grading all increased after 3 weeks of use. Skin barrier function measured using transepidermal water loss also improved. Levels of cholesterol, free fatty acids and Ceramide NH increased, as well as the average length of the stratum corneum (SC) lipid lamella bilayers, and the ratio of lipid to protein increased (measured using Lipbarvis® and in vivo Confocal Raman Spectroscopy). Increases in the levels of Ceramide EOS and NP were also observed, along with an improvement in corneocyte maturity, although these were not statistically significant.Using a variety of traditional and novel skin assessment techniques, a wide range of factors associated with the evolution of dry skin have been assessed upon treatment with a new topical moisturizer. Product usage resulted in significant improvements to skin hydration and barrier function, the levels and morphology of SC barrier lipids, and overall epidermal differentiation. As a result there was a significant reduction in the characteristics associated with the development of dry skin after use of the test product.OBJECTIF: le développement de la sécheresse cutanée est un processus complexe, une grande variété de facteurs jouant chacun des rôles différents dans son évolution. De ce fait, il est important d’aborder ces différents aspects du comportement de la peau lors de la conception d’une formulation pour lutter contre la sécheresse cutanée. Les résultats d’une étude de 3 semaines sur l’hydratation des jambes sèches sont présentés ci-dessous. Un large éventail de méthodes de mesure biophysiques traditionnelles et plus récemment développées ont été combinées à une évaluation visuelle de l’état de la peau pour permettre de déterminer de multiples aspects de la fonction cutanée. Les changements observés sur la peau sont abordés en termes des ingrédients utilisés dans la formulation hydratante. MÉTHODES: une série de méthodes et de techniques nouvelles et traditionnelles d’évaluation de la peau ont été utilisées pour évaluer les effets d’un produit hydratant à base d’émulsion huile dans eau par comparaison à un site non traité au cours d’une étude in vivo de 3 semaines sur la peau sèche de la partie inférieure des jambes. RÉSULTATS: des améliorations statistiquement significatives ont été observées au niveau d’une gamme de paramètres cutanés suite à l’utilisation du produit. L’hydratation cutanée évaluée à l’aide de Corneometer®, Epsilon® et de la cotation visuelle de la sécheresse cutanée s’est améliorée selon toutes ces méthodes après 3 semaines d’utilisation. La fonction de barrière cutanée mesurée d’après la perte d’eau transépidermique s’est également améliorée. Les taux de cholestérol, d’acides gras libres et de céramides NH ont augmenté, ainsi que la longueur moyenne des bicouches des lamelles lipidiques de la couche cornée (CC), et il en a été de même pour le rapport lipide/protéine (mesuré à l’aide du Lipbarvis® et de la spectroscopie confocale de Raman in vivo). Des augmentations des taux de céramides EOS et NP ont également été observées, ainsi qu’une amélioration de la maturité des cornéocytes, bien qu’elles n’aient pas été statistiquement significatives. CONCLUSION: à l’aide d’une gamme de techniques d’évaluation de la peau traditionnelles et nouvelles, un large éventail de facteurs associés à l’évolution de la sécheresse cutanée a été évalué lors du traitement avec un nouveau produit hydratant topique. L’utilisation du produit a entraîné une amélioration significative de l’hydratation et de la fonction de barrière de la peau, des taux et de la morphologie des lipides de la barrière SC , et de la différenciation épidermique globale. Cela a entraîné une amélioration significative des facteurs associés au développement de la sécheresse cutanée.

Skin barrier dysfunction caused by endogenous or exogenous factors can lead to various disorders such as xerosis cutis, ichthyoses, and atopic dermatitis. Filaggrin is a pivotal structural protein of the stratum corneum (SC) and provides natural moisturizing factors that play a role in skin barrier functions. Filaggrin aggregates keratin filaments, resulting in the formation of a keratin network, which binds cornified envelopes and collapse keratinocytes to flattened corneocytes. This complex network contributes to the physical strength of the skin. Filaggrin is degraded by caspase-14, calpain 1, and bleomycin hydrolases into amino acids and amino acid metabolites such as trans-urocanic acid and pyrrolidone carboxylic acid, which are pivotal natural moisturizing factors in the SC. Accordingly, filaggrin is important for the pathophysiology of skin barrier disorders, and its deficiency or dysfunction leads to a variety of skin disorders. Here, the roles and biology of filaggrin, related skin diseases, and a therapeutic strategy targeting filaggrin are reviewed. In addition, several drug candidates of different mode of actions targeting filaggrin, along with their clinical efficacy, are discussed.

Polyols are moisturizers used in cosmetics. Using X-ray diffraction, we studied the moisturizingmechanism of polyol solutions in the stratum corneum (SC). We examined whether glycerol disrupts the ordered hydrocarbon chain packing structure in isolated SC, as previously proposed in an SC lipid model.The SC samples were prepared by treatment with water and aqueous solutions of glycerol, diglycerol and glycerol/diglycerol. To examine the differences in the water-retention efficiency of polyols, using a solution cell, we performed dynamic X-ray diffraction to analyse the structural changes that occurred during water removal from the hydrated samples by a stream of dry nitrogen gas. We focused on two structures, the orthorhombic hydrocarbon chain packing structure in the intercellular lipids and the soft keratin in the corneocytes where most of the water is stored.The spacing formed by the soft keratin in the corneocytes immersed in a solution of water and diglycerol solution decreased rapidly by water removal. In contrast, it decreased gradually in the corneocytes immersed in a solution of glycerol and glycerol/diglycerol, indicating that the glycerol-containing solutions maintained the hydrated state of the corneocytes for longer. Furthermore, the characteristic change of the spacing in the orthorhombic hydrocarbon chain packing structure over time was observed during the drying process. The hydrated state was maintained longer, in water, followed by glycerol, diglycerol and glycerol/diglycerol, in increasing order. This is the first study to report such characteristic properties that could be indicators of the capacity of the SC to regulate water.The dynamic X-ray diffraction experiment on the structure of the soft keratin and the orthorhombic hydrocarbon chain packing structure during the drying of the hydrated SC provides an insight into the moisturizing mechanism of the polyol solutions in the SC. The results show that the glycerol/diglycerol solution functions as an effective SC moisturizer at the molecular level. Further, it was confirmed that the behaviour of glycerol in the isolated SC varies from that proposed in the SC lipid model, wherein glycerol was proposed to prevent the formation of a regular hydrocarbon chain packing structure.OBJECTIF: les polyols sont des hydratants utilisés dans les cosmétiques. À l’aide de la diffractions des rayons X, nous avons étudié le mécanisme d’hydratation des solutions de polyols dans la couche cornée (stratum corneum, SC).Notre étude avait pour but de déterminer si le glycérol perturbe la structure d’empilement de la chaîne d’hydrocarbures ordonnée dans les SC isolés, comme proposé précédemment dans un modèle lipidique de SC. MÉTHODES: les échantillons de SC ont été préparés avec de l’eau et des solutions aqueuses de glycérol, de diglycérol et de glycérol/diglycérol. Pour examiner les différences d’efficacité de rétention d’eau des polyols à l’aide d’une cellule de solution, nous avons effectué une diffraction dynamique des rayons X pour analyser les changements structurels qui se sont produits pendant l’élimination de l’eau des échantillons hydratés par un flux d’azote sec. Nous avons mis l’accent sur deux structures, la structure d’empilement des chaînes d’hydrocarbures orthorhombiques dans les lipides intercellulaires et la kératine molle dans les cornéocytes où la majeure partie de l’eau est stockée. RÉSULTATS: l’espacement causé par la kératine molle dans les cornéocytes immergés dans une solution d’eau et de diglycérol a diminué rapidement en raison de l’élimination de l’eau. En revanche, il a diminué progressivement dans les cornéocytes immergés dans une solution de glycérol et de glycérol/diglycérol, ce qui indique que les solutions contenant du glycérol ont maintenu l’état hydraté des cornéocytes plus longtemps. De plus, la modification caractéristique de l’espacement dans la structure d’empilement de la chaîne d’hydrocarbures orthorhombique au fil du temps a été observée au cours du processus de séchage. L’état hydraté a été maintenu plus longtemps, dans l’eau, suivi par le glycérol, le diglycérol et le glycérol/diglycérol, dans un ordre croissant. C’est la première étude à faire état de telles propriétés caractéristiques qui pourraient être des indicateurs de la capacité du SC à réguler l’eau. CONCLUSION: l’expérience de diffraction dynamique des rayons X sur la structure de la kératine molle et la structure d’empilement de la chaîne d’hydrocarbures orthorhombique pendant le séchage du SC hydraté donne un aperçu du mécanisme hydratant des solutions de polyols dans le SC. Les résultats montrent que la solution de glycérol/diglycérol agit comme un hydratant de SC efficace au niveau moléculaire. De plus, il a été confirmé que le comportement du glycérol dans le SC isolé varie par rapport à celui proposé dans le modèle lipidique SC, où le glycérol a été proposé pour prévenir.

Age-related differences in maturation parameters of corneocyte envelopes (size, hydrophobicity and rigidity) were examined at several facial test sites in young and old female Caucasians. In addition, the effect of topically applied niacinamide on these parameters was evaluated in a 4-week placebo-controlled study.

Aim The purpose of this study was to investigate the degradation of desmocollin-1 (DSC1), a member of the desmosomal cadherin family in patients with diabetes, as well as the factors associated with the suppression of DSC1 degradation. Methods This cross-sectional study included 60 cases of foot callus involving 30 patients with diabetes (DM) and 30 matched volunteers without diabetes (non-DM). DSC1 degradation in samples from debrided calluses was analysed using western blotting. Skin hydration, a factor reported to suppress DSC1 degradation, was measured using a mobile moisture device. Results Full-length DSC1 (approximately 100 kDa) was detected in six participants only in the DM group, and no relationship was found between the suppression of DSC1 degradation and decreased skin hydration in the DM group. There was no significant difference in skin hydration values between the DM and non-DM groups. Conclusion DSC1 degradation was suppressed in the DM group. There was no relationship between the suppression of DSC1 degradation and decreased skin hydration in the DM group. Current external force callus care would not be sufficient. This study highlights the need to develop novel callus care to enhance the degradation of DSC1.

Irritant contact dermatitis is a wide spread occupational skin condition. In addition to generalized protection and teaching schemes, a knowledge about individual risk might add to an improved awareness for hazards. Here, we report on a novel candidate biomarker, which might stage individual susceptibility to irritant skin damage. Subclinical sensitivity was proven in recent studies. As a nano-anatomical measure, it works non-invasively on corneocytes from tape strips. Here, we report on a 7-day course after exposure to sodium lauryl sulphate and compare the novel cell texture index with the classical markers water loss (transepidermal water loss) and natural moisturizing factor. All parameters show a high degree of correlation.

The penetration mechanism of choline chloride‐glycerol deep eutectic solvent (DES) through the stratum corneum (SC) as a potential solvent for a novel enhancer of protein penetration into the skin was investigated in a wide and small angle X‐ray diffraction study. We found that DES penetrated through intercellular lipids but not the corneocytes. DES seemed to extract a portion of lipids of the short lamellae in the SC. Hydrated DES with a DES to water weight ratio of 9 to 1 (9DES‐1H2O) showed the strongest interaction with the lipids in the SC compared with water, DES, and hydrated DESs with another weight ratio of DES to water (DES : water=8 : 2). In a skin penetration test with a fluorescently labelled lysozyme, 9DES‐1H2O increased the amount of penetration through the SC by two‐fold compared with HEPES buffer., Drug delivery: The penetration mechanism of choline chloride‐glycerol deep eutectic solvent (DES) through the stratum corneum (SC) as a potential solvent for a novel enhancer of protein penetration into the skin was investigated in an X‐ray diffraction study. We found that hydrated DES increased the penetration of lysozyme through the SC due to the disruption of the short lipid lamellar structures through partial extraction of lipids in the SC.

Background Inflammatory skin disorders, including atopic dermatitis (AD), associated pruritus and sensitive skin, have a complex multifactorial pathogenesis including neurogenic inflammation involving the release in blood and skin of neurotransmitters such as substance P (SP). Aims and methods In vitro models evaluated the effect of the original biological extract of Aquaphilus dolomiae extract-G3 (ADE-G3) on cutaneous neurogenic inflammation. Results ADE-G3 significantly inhibited SP-stimulated release of IL-1β and TNF-α from normal human epidermal keratinocytes; significantly and dose-dependently inhibited SP-stimulated activation of human mast cells; significantly inhibited veratridine-stimulated release of SP from human sensory neurons; modulated expression of genes involved in lipid synthesis, innate immunity, corneocyte scaffolding and epidermal differentiation in a histamine-sensitized reconstructed human epidermis model; and, when applied topically to ex vivo human explants, inhibited IL-8 and histamine release. Conclusions Topically applied ADE-G3, once formulated, may improve neuro-inflammation in patients with inflammatory skin disorders.

Background Recently, light-emitting diode (LED) devices are among those mostly preferred for esthetic application because they improve the appearance of photoaged skin characterized by wrinkles, sagginess, pigmented lesions, and others. In addition, the use of hyaluronic acid (HA) for skin rejuvenation is already well proven. Aims This study aims to evaluate the synergistic effects of using home-use LED mask device with HA ampoule. Methods The total number of recruited subjects was 48:24 in Group A treated with both home-use LED mask device and HA ampoule and 24 in Group B treated with HA ampoule only, for 4 weeks. To assess the efficacy of the treatment, the following were used: Antera 3D CS, EOS 800D with Image-Pro Plus, DUB-USB, VisioFace Quick, and Visioscan VC98. Results After treatment, the volume measurement (mm3 ) for prejowl sulci and nasolabial fold flattening as well as the area measurement (pixel) for lower chin firmness improvement was significantly reduced, and the number of pores (ea) for enlarged pores as well as the desquamation index (%) for the amount of corneocytes significantly decreased in both Group A and Group B. Moreover, the percentage of skin density significantly improved. Furthermore, Group A showed a significantly faster and higher rate of improvement than Group B. Conclusion The use of 660- and 850-nm home-use LED mask device can generate synergistic effects on home-use topical applications like HA on photoaged face, and such device can be safely and efficiently used daily in personal environments.

The development of the beak in turtles is poorly known. Beak development has been analyzed by immunofluorescent methods for studying cell proliferation and localization of specific proteins. The flat two-layered epidermis covering the turtle embryo at mid stage of development becomes columnar in the oral region and is associated with an increase of mesenchymal density as in placodes. Using 5BrdU, an intense cell proliferation is observed in the oral and epidermal cells covering the maxilla and mandibular bones, probably stimulated by the underlying mesenchyme in continuation with maxillary and mandibular bones. Expansion and fusion of these placodes give rise to the corneous beak. Beta catenin, mainly junctional but also sparsely detected in nuclei of the germinal layer of the beak epithelium, maintains united the differentiating keratinocytes that form a stratified corneous epithelium. This is initially composed of some layers of large cells that accumulate intermediate filament keratins (IFKs) and give rise to a keratinized embryonic epidermis destined to slough around hatching. The following corneocytes accumulate IFKs but mainly type I/II corneous beta proteins (CBPs) and form a corneous beak. These CBPs appear present with lower intensity in the beak than in the shell, but the higher intensity obtained with a general antibody against CBPs indicates that other CBPs contribute to the composition and stiffness of beak corneous material. The egg-tooth in continuation with the stratum corneum of the maxillary beak develops from a localized proliferation and comprises a thick embryonic epidermis accumulating IFKs under which large beta-cells connected by adhesion proteins accumulate CBPs contributing to hardening of this temporary organ.

Among the components of the barrier structure of the stratum corneum in human skin, the corneocyte lipid envelope (CLE) is extremely important for the skin barrier. The importance of the CLE and esterified ω-hydroxy sphingosine (CerEOS), its main precursor, has been suggested from the fact that mutations in a number of genes involved in CerEOS synthesis and CLE formation have been identified as genetic causes of congenital ichthyoses, which are severe genetic skin disorders. However, the molecule/mechanism involved in the covalent binding of CerEOS to proteins on the outer surface of the cornified cell envelope had been a missing part. Very recently, we proposed new potential modes of protein binding by covalent reactions of CerEOS-epoxy-enone. We revealed the biochemical function of short-chain dehydrogenase/reductase family 9C member 7 (SDR9C7), encoded by SDR9C7, as catalyzing the dehydrogenation of the lipoxygenase products that are esterified in CerEOS. Epoxy-enone produced by SDR9C7 covalently binds to proteins on the outer extracellular surface of the cornified cell envelope. Importantly, our recent striking findings were derived from the detailed lipid analysis of only one ARCI patient with SDR9C7 mutation. The combination of detailed analyses of precious samples from a rare patient and the establishment of corresponding animal models is an effective and powerful tool for analyzing rare inherited diseases. This review summarizes this newly revealed mechanism in skin barrier formation, describes the characteristic features of patients with SDR9C7 mutations, and introduces the clinical value of non-invasive analyses for patients with very rare intractable skin diseases.

The corneocyte lipid envelope, composed of covalently bound ceramides and fatty acids, is important to the integrity of the permeability barrier in the stratum corneum, and its absence is a prime structural defect in various skin diseases associated with defective skin barrier function. SDR9C7 encodes a short-chain dehydrogenase/reductase family 9C member 7 (SDR9C7) recently found mutated in ichthyosis. In a patient with SDR9C7 mutation and a mouse Sdr9c7-KO model, we show loss of covalent binding of epidermal ceramides to protein, a structural fault in the barrier. For reasons unresolved, protein binding requires lipoxygenase-catalyzed transformations of linoleic acid (18:2) esterified in ω-O-acylceramides. In Sdr9c7(–/–) epidermis, quantitative liquid chromatography–mass spectometry (LC-MS) assays revealed almost complete loss of a species of ω-O-acylceramide esterified with linoleate-9,10-trans-epoxy-11E-13-ketone; other acylceramides related to the lipoxygenase pathway were in higher abundance. Recombinant SDR9C7 catalyzed NAD(+)-dependent dehydrogenation of linoleate 9,10-trans-epoxy-11E-13-alcohol to the corresponding 13-ketone, while ichthyosis mutants were inactive. We propose, therefore, that the critical requirement for lipoxygenases and SDR9C7 is in producing acylceramide containing the 9,10-epoxy-11E-13-ketone, a reactive moiety known for its nonenzymatic coupling to protein. This suggests a mechanism for coupling of ceramide to protein and provides important insights into skin barrier formation and pathogenesis.

The skin is the largest organ in the human body; beyond its regulatory and sensory roles, it is meant to protect and act like a barrier against foreign matter. Products intended to restore the skin health should reintegrate the structure of the stratum corneum in which the corneocytes are surrounded by the intercellular lipid lamellae that maintain both corneum integrity and skin permeability barrier. Capilen is a specific liposomal formulation based on a technology through which highly concentrated fresh plant extracts are conveyed into a jelly-like liposomal vehicle and combined with plant-derived omega-3, -6, -7, and -9 fatty acids, phospholipids, and precursors of ceramides. Its components have been widely investigated and produced clinical benefits in atopic dermatitis, bedsores, scars, inflammatory lesions of the skin, and generally whenever signs of xerosis cutis were present. Liposomes contribute to restore the surface lipid layer of the skin and to deliver substances in the activity site. This liposomal cream was proven to limit and delay the occurrence of radiodermatitis in breast cancer patients, and as an add-on provided complete healing of bedsore lesions in geriatric subjects.

A panel of four lectins was used to investigate the role of carbohydrates in the adherence of Malassezia pachydermatis to canine corneocytes in vitro. Pretreatment of canine corneocytes with concanavalin A (10 μg ml-1 ) inhibited (P < 0.01) the adherence of one out of six M. pachydermatis strains. This effect was abrogated by pre-incubating concanavalin A with its hapten inhibitor (6% methyl α-d-mannopyranoside), suggesting that mannosyl-bearing carbohydrate residues on the epithelial cells serve as ligands for adhesins expressed by this strain. However, treatment of corneocytes with soybean, wheat germ and gorse lectin, and pretreatment of the yeast cells with either of the four lectins had no reproducible effect on the adherence of two strains.

A prospective clinical trial was carried out in a 6-week-old male Jack Russell terrier with congenital ichthyosis to evaluate stratum corneum lipids; transmission electron microscopy of skin specimens; and clinical and dermatopathological response to vitamin A alcohol therapy. Also evaluated were the clinical, dermatopathological, and epidermal cell proliferation kinetics response to a synthetic retinoid in a dog with congenital ichthyosis. Epidermal cell renewal time was markedly decreased compared with normal and seborrhoeic dogs. Skin specimens were characterized by severe and diffuse compact orthokeratosis that extended into the infundi-bulum of the hair follicles. The stratum granulosum was normal. On transmission electron microscopy, the stratum corneum was thickened and intercorneocyte spaces were extremely narrow. The first three corneocyte layers contained tonofilaments that were irregular, coarse and wavy. Tonofilament packing appeared more normal and regular in the fourth and fifth corneocyte layers. Outer layers of stratum corneum were extraordinarily electron-dense compared with normal. There was a decrease in stratum corneum free fatty acid and acyl-ceramide and an increase in ceramide III levels compared with three normal dogs. Three months of oral vitamin A alcohol did not result in clinical improvement, although histologically the orthokeratosis was less compact. After 6 months of oral etretinate therapy, comedones and scales were markedly less evident grossly. Although compact orthokeratosis was still present on histological examination of skin, it was less than that present at 6 weeks of age. Epidermal cell kinetics were not altered after etretinate therapy.

The stratum corneum is the outermost layer of the epidermis and is thus directly exposed to the environment. It consists mainly of corneocytes, which are keratinocytes in the last stage of differentiation, having neither nuclei nor organelles. However, they retain keratin filaments embedded in filaggrin matrix and possess a lipid envelope which protects the body from desiccation. Despite the desiccated, nutrient-poor, and acidic nature of the skin making it a hostile environment for most microorganisms, this organ is colonized by commensal microbes. Among the classic skin commensals are Propionibacterium acnes and coagulase-negative staphylococci (CoNS) with Staphylococcus epidermidis as a leading species. An as-yet-unanswered question is what enables S. epidermis to colonize skin so successfully. In their recent article, P. D. Fey and his colleagues (P. Roy, A. R. Horswill, and P. D. Fey, mBio 12:e02908-20, 2021, https://doi.org/10.1128/mBio.02908-20) have brought us one step closer to answering this question.

Moisturizing compounds are commonly applied topically to human stratum corneum (SC). Many types of molecular species are employed, most commonly including humectants and occlusives. We find new evidence of keratin dispersion caused by the moisturizing compound ectoine (1,4,5,6-tetrahydro-2-methyl-4-pyrimidinecarboxylic acid), and provide the first characterization of its impacts on the hydration kinetics and biomechanics of SC. A second compound, 2-(2-hydroxyethoxy)ethylguanidine succinate (HEG) was investigated for comparison. A suite of biomechanical and biochemical assays including FTIR, drying stress, and cellular cohesion were used. Studies were conducted on normal, lipid-extracted, and lipid plus natural moisturizing factor extracted SC. Ectoine was found to improve the dispersity and hydration of keratin bundles in corneocytes. It also decreased rates of stress development in lipid extracted SC when exposed to a dry environment by ∼30% while improving stress reduction during rehydration by ∼20%. Peak stresses were increased in harsh drying environments of, Highlights • First study demonstrating the biomechanical impact of keratin dispersion on human skin • Ectoine disperses keratin bundles in human stratum corneum • Rates of drying stress development are reduced in keratin-dispersed skin • Rehydration rates are increased in keratin-dispersed skin • Keratin dispersion alters corneocyte cohesion profiles

Staphylococcus epidermidis and other coagulase-negative staphylococci (CoNS) that colonize skin are known to promote skin immunity and inhibit colonization of pathogens that cause skin and soft tissue infections, including Staphylococcus aureus. However, S. epidermidis adherence to corneocytes, the cells that constitute the uppermost layer of the skin epidermis, remains poorly understood. Our study documents that S. epidermidis corneocyte adherence is dependent upon the accumulation-associated protein (Aap). Aap is composed of two distinct A and B domains. The A domain is comprised of a repeat region and a conserved L-type lectin domain, whereas the fibrillar B domain, which is comprised of G5 and E repeats, is linked to the cell wall in a sortase-dependent manner. Our studies revealed that adherence to corneocytes is dependent upon the lectin subdomain within the A domain. However, significant adherence was only observed when the lectin domain was expressed with both the A repeat and the B domain, suggesting further interactions between these three domains. Our data also suggest that the A repeat domain is important for stability or expression of Aap. Deglycosylation treatment suggested that glycans expressed in the host stratum corneum serve as potential binding partners for Aap-mediated corneocyte adherence. Last, bioinformatic analyses of the predominant commensal species of CoNS identified open reading frames (ORFs) homologous to aap, thus suggesting that Aap orthologues containing lectin-like domains may provide the basis for staphylococcal colonization of skin. Corroborating these observations, adherence to corneocytes in an S. aureus mgrA mutant was dependent upon SasG, the Aap orthologue in S. aureus. IMPORTANCE Staphylococcus aureus is the most significant cause of skin and soft tissue infections yet it rarely colonizes the skin of healthy individuals. This is believed to be due, in part, to inhibition of colonization via toxic substances produced by normal skin flora, including by S. epidermidis. Furthermore, we surmise that S. aureus colonization inhibition may also be due to competition for binding sites on host corneocytes. To understand these potential interactions between S. aureus and S. epidermidis and, potentially, other coagulase-negative staphylococci, we must first understand how staphylococci adhere to corneocytes. This work documents that S. epidermidis adherence to corneocytes is dependent upon the fibrillar cell wall-associated protein Aap. Our work further documents that Aap binds to glycans exposed on the corneocyte surface, which are commonly exploited by bacteria to facilitate adherence to host cells. Furthermore, we find that Aap orthologues may be responsible for corneocyte adherence in other staphylococci, including in S. aureus.

Studies on the effectiveness of substances such as drugs and cosmetics that act on the skin require structural evidence at the molecular level in the stratum corneum to clarify their interaction with intercellular lipid and soft keratin. For this purpose, when applying the substances to the stratum corneum X-ray diffraction experiment is one of the powerful tools. To detect minute structural changes in a stratum corneum sample, using a "solution cell", dynamic synchrotron X-ray diffraction measurements were performed when applying aqueous solution of the substances to the stratum corneum: (1) It was found that a surfactant, sodium dodecyl sulfate, significantly disrupted the long-period lamellar structure. (2) To study the effects of water, structural modifications of the short-period lamellar structure and the soft keratin in corneocytes were measured as a function of time. At the initial water content of 15 wt%, the spacings of the short-period lamellar structure and the soft keratin increased toward those at the water content of 25 wt%, that is a key water content in the stratum corneum. (3) Nanoparticles composed of assembly of amphiphilic molecules are one of the leading pharmaceutical formulations. When the nanoparticles were applied, a new assembly of amphiphilic molecules originated from the nanoparticle appeared. This phenomenon suggests that the formation of the new assembly at the surface of skin is concerned with the release of the drug from the nanoparticles. (4) When ethanol was applied to the stratum corneum, only the liquid state in the intercellular lipid matrix was dissolved. After the removal of ethanol from this stratum corneum, the ordered hydrocarbon-chain packing structures appeared. From this fact we would propose that the liquid state region is the main pathway for hydrophobic drugs with a small molecular weight in connection with the so-called 500 Da rule. Here, not only the technique but also the background to these studies and the characteristic results obtained from these studies are explained.

Liposomes are nano size artificial vesicles of spherical shape that can be produced from natural phospholipids and cholesterol. Liposomes are defined as spherical Micro- or Nano-sized particles that contain an internal water pool surrounded by a bilaminar membrane. The building blocks of the membrane are phospholipid molecules or a combination of phospholipids with sterols, such as cholesterol, or with other surface -active ingredients. Liposomes are nano-scale spheroid vesicles composed of one or multiple lipid bilayer (s) enclosing an aqueous core. Liposomes can be manufactured using several methods, including thin-film hydration, reverse phase evaporation, and microfluidic mixing. Liposomal preparation reduce the roughness because of its interaction with corneocytes, the intracellular lipid resulting in skin softening and smoothing. Various liposome based products for facial and body care, make-up, mascara & foundation, haircare, sunscreen products & perfumes are in market.