Increased 1-Deoxysphingolipids and Skin BarrierDysfunction in the Skin of X-ray or Ultraviolet BIrradiation and Atopic Dermatitis Lesion Could BePrevented by Moisturizer with Physiological LipidMixture

Background@#Skin diseases characterized by epithelial barrierdysfunction show altered sphingolipid metabolism,which results in changes in the stratum corneum intercellularlipid components and structure. Under pathological conditions,1-deoxysphingolipids form as atypical sphingolipidsfrom de novo sphingolipid biosynthesis. @*Objective@#Thisstudy investigated the potential role of 1-deoxysphingolipidsin skin barrier dysfunction secondary to X-ray and ultravioletB (UVB) irradiation in vitro and in vivo. It was also evaluatedchanges in the expression of 1-deoxysphingolipids in lesionalhuman skin of atopic dermatitis. @*Methods@#In thisstudy, the changes in these 1-deoxysphingolipids levels ofskin and serum samples were investigated in skin barrier dysfunctionassociated with X-ray and UVB irradiation in vitroand in vivo. @*Results@#Increased 1-deoxysphingolipids were observed in cultured normal human epidermal keratinocytesafter X-ray irradiation. X-ray or UVB irradiation increased theproduction of 1-deoxysphingosine in a reconstituted 3-dimensional(3D) skin model. Interestingly, treatment with aphysiological lipid mixture (multi-lamellar emulsion containedpseudoceramide), which can strengthen the epidermalpermeability barrier function, resulted in decreased1-deoxysphingosine formation in a reconstituted 3D skinmodel. Further investigation using a hairless mouse modelshowed similar preventive effects of physiological lipid mixtureagainst 1-deoxysphingosine formation after X-ray irradiation.An increased level of 1-dexoysphingosine in the stratumcorneum was also observed in lesional skin of atopic dermatitis. @*Conclusion@#1-deoxysphingosine might be a novelbiomarker of skin barrier dysfunction and a physiological lipidmixture treatment could prevent 1-deoxysphingosine productionand consequent skin barrier dysfunction.

Aquatide Activation of SIRT1 Reduces Cellular Senescence through a SIRT1-FOXO1-Autophagy Axis

Ultraviolet (UV) irradiation is a relevant environment factor to induce cellular senescence and photoaging. Both autophagy- and silent information regulator T1 (SIRT1)-dependent pathways are critical cellular processes of not only maintaining normal cellular functions, but also protecting cellular senescence in skin exposed to UV irradiation. In the present studies, we investigated whether modulation of autophagy induction using a novel synthetic SIRT1 activator, heptasodium hexacarboxymethyl dipeptide-12 (named as Aquatide), suppresses the UVB irradiation-induced skin aging. Treatment with Aquatide directly activates SIRT1 and stimulates autophagy induction in cultured human dermal fibroblasts. Next, we found that Aquatide-mediated activation of SIRT1 increases autophagy induction via deacetylation of forkhead box class O (FOXO) 1. Finally, UVB irradiation-induced cellular senescence measured by SA-β-gal staining was significantly decreased in cells treated with Aquatide in parallel to occurring SIRT1 activation-dependent autophagy. Together, Aquatide modulates autophagy through SIRT1 activation, contributing to suppression of skin aging caused by UV irradiation.

Selective Cannabinoid Receptor-1 Agonists Regulate Mast Cell Activation in an Oxazolone-Induced Atopic Dermatitis Model

BACKGROUND: Many inflammatory mediators, including various cytokines (e.g. interleukins and tumor necrosis factor [TNF]), inflammatory proteases, and histamine are released following mast cell activation. However, the endogenous modulators for mast cell activation and the underlying mechanism have yet to be elucidated. Endogenous cannabinoids such as palmitoylethanolamide (PEA) and N-arachidonoylethanolamine (anandamide or AEA), were found in peripheral tissues and have been proposed to possess autacoid activity, implying that cannabinoids may downregulate mast cell activation and local inflammation. OBJECTIVE: In order to investigate the effect of cannabinoid receptor-1 (CB1R) agonists on mast cell activation, AEA-derived compounds were newly synthesized and evaluated for their effect on mast cell activation. METHODS: The effects of selected compounds on FcepsilonRI-induced histamine and beta-hexosaminidase release were evaluated in a rat basophilic leukemia cell line (RBL-2H3). To further investigate the inhibitory effects of CB1R agonist in vivo, an oxazolone-induced atopic dermatitis mouse model was exploited. RESULTS: We found that CB1R inhibited the release of inflammatory mediators without causing cytotoxicity in RBL-2H3 cells and that CB1R agonists markedly and dose-dependently suppressed mast cell proliferation indicating that CB1R plays an important role in modulating antigen-dependent immunoglobulin E (IgE)-mediated mast cell activation. We also found that topical application of CB1R agonists suppressed the recruitment of mast cells into the skin and reduced the level of blood histamine. CONCLUSION: Our results indicate that CB1R agonists down-regulate mast cell activation and may be used for relieving inflammatory symptoms mediated by mast cell activation, such as atopic dermatitis, psoriasis, and contact dermatitis.

Antibody to FcεRIα Suppresses Immunoglobulin E Binding to High-Affinity Receptor I in Allergic Inflammation

PURPOSE: High-affinity receptor I (FcεRI) on mast cells and basophils plays a key role in the immunoglobulin E (IgE)-mediated type I hypersensitivity mediated by allergen cross-linking of the specific IgE-FcεRI complex. Thus, prevention of IgE binding to FcεRI on these cells is an effective therapy for allergic disease. We have developed a strategy to disrupt IgE binding to FcεRI using an antibody targeting FcεRIα. MATERIALS AND METHODS: Fab fragment antibodies, which lack the Fc domain, with high affinity and specificity for FcεRIα and effective inhibitory activity against IgE-FcεRI binding were screened. IgE-induced histamine, β-hexosaminidase and Ca2+ release in basophils were determined by ELISA. A B6.Cg-Fcer1a(tm1Knt) Tg(FCER1A)1Bhk/J mouse model of passive cutaneous anaphylaxis (PCA) was used to examine the inhibitory effect of NPB311 on allergic skin inflammation. RESULTS: NPB311 exhibited high affinity to human FcεRIα (KD=4 nM) and inhibited histamine, β-hexosaminidase and Ca2+ release in a concentration-dependent manner in hFcεRI-expressing cells. In hFcεRIα-expressing mice, dye leakage was higher in the PCA group than in controls, but decreased after NPB311 treatment. NPB311 could form a complex with FcεRIα and inhibit the release of inflammation mediators. CONCLUSION: Our approach for producing anti-FcεRIα Fab fragment antibody NPB311 may enable clinical application to a therapeutic pathway in IgE/FcεRI-mediated diseases.

Antibody to FcεRIα Suppresses Immunoglobulin E Binding to High-Affinity Receptor I in Allergic Inflammation

PURPOSE: High-affinity receptor I (FcεRI) on mast cells and basophils plays a key role in the immunoglobulin E (IgE)-mediated type I hypersensitivity mediated by allergen cross-linking of the specific IgE-FcεRI complex. Thus, prevention of IgE binding to FcεRI on these cells is an effective therapy for allergic disease. We have developed a strategy to disrupt IgE binding to FcεRI using an antibody targeting FcεRIα. MATERIALS AND METHODS: Fab fragment antibodies, which lack the Fc domain, with high affinity and specificity for FcεRIα and effective inhibitory activity against IgE-FcεRI binding were screened. IgE-induced histamine, β-hexosaminidase and Ca2+ release in basophils were determined by ELISA. A B6.Cg-Fcer1a(tm1Knt) Tg(FCER1A)1Bhk/J mouse model of passive cutaneous anaphylaxis (PCA) was used to examine the inhibitory effect of NPB311 on allergic skin inflammation. RESULTS: NPB311 exhibited high affinity to human FcεRIα (KD=4 nM) and inhibited histamine, β-hexosaminidase and Ca2+ release in a concentration-dependent manner in hFcεRI-expressing cells. In hFcεRIα-expressing mice, dye leakage was higher in the PCA group than in controls, but decreased after NPB311 treatment. NPB311 could form a complex with FcεRIα and inhibit the release of inflammation mediators. CONCLUSION: Our approach for producing anti-FcεRIα Fab fragment antibody NPB311 may enable clinical application to a therapeutic pathway in IgE/FcεRI-mediated diseases.

A Novel Synthetic Mycolic Acid Inhibits Bronchial Hyperresponsiveness and Allergic Inflammation in a Mouse Model of Asthma

PURPOSE: Recognition of microbes is important to trigger the innate immune system. Mycolic acid (MA) is a component of the cell walls of mycobacteria such as Mycobacterium bovis Bacillus Calmette-Guerin. MA has immunogenic properties, which may modulate the innate and adaptive immune response. This study aimed to investigate whether a novel synthetic MA (sMA) inhibits allergic inflammatory responses in a mouse model of asthma. METHODS: BALB/c mice were injected intraperitoneally with sMA followed by sensitization and challenge with ovalbumin (OVA). Mice were examined for bronchial hyperresponsiveness (BHR), the influx of inflammatory cells into the lung tissues, histopathological changes in the lungs and CD4+CD25+Foxp3+ T cells in the spleen, and examined the response after the depleting regulatory T cells (Tregs) with an anti-CD25mAb. RESULTS: Treatment of mice with sMA suppressed the asthmatic response, including BHR, bronchoalveolar inflammation, and pulmonary eosinophilic inflammation. Anti-CD25mAb treatment abrogated the suppressive effects of sMA in this mouse model of asthma and totally depleted CD4+CD25+Foxp3+ T cells in the spleen. CONCLUSIONS: sMA attenuated allergic inflammation in a mouse model of asthma, which might be related with CD4+CD25+Foxp3+ T cell.

Preventive Effects of Multi-Lamellar Emulsion on Low Potency Topical Steroid Induced Local Adverse Effect

BACKGROUND: Topical steroid treatment induces diverse local Wand systemic adverse effects. Several approaches have been tried to reduce the steroid-induced adverse effects. Simultaneous application of physiological lipid mixture is also suggested. OBJECTIVE: Novel vehicles for topical glucocorticoids formulation were evaluated for the efficacy of reducing side-effects and the drug delivery properties of desonide, a low potency topical steroid. METHODS: Transcutaneous permeation and skin residual amount of desonide were measured using Franz diffusion cells. The in vivo anti-inflammatory activity was evaluated using murine model. RESULTS: Topical steroids formulation containing desonide, in either cream or lotion form, were prepared using multi-lamellar emulsion (MLE), and conventional desonide formulations were employed for comparison. MLE formulations did not affect the anti-inflammatory activity of the desonide in phobol ester-induced skin inflammation model, compared with conventional formulations. While the penetrated amounts of desonide were similar for all the tested formulations at 24 hours after application, the increased lag time was observed for the MLE formulations. Interestingly, residual amount of desonide in epidermis was significantly higher in lotion type MLE formulation. Steroid-induced adverse effects, including permeability barrier function impairment, were partially prevented by MLE formulation. CONCLUSION: Topical desonide formulation using MLE as a vehicle showed a better drug delivery with increased epidermal retention. MLE also partially prevented the steroid-induced side effects, such as skin barrier impairment.

Pseudoceramide-Containing Physiological Lipid Mixture Reduces Adverse Effects of Topical Steroids

PURPOSE: Various therapeutic approaches have been suggested for preventing or reducing the adverse effects of topical glucocorticoids, including skin barrier impairment. Previously, we have shown that impairment of skin barrier function by the highest potency topical glucocorticoid, clobetasol 17-propinate (CP), can be partially prevented by co-application of a physiological lipid mixture containing pseudoceramide, free fatty acids, and cholesterol (multi-lamellar emulsion [MLE]). Skin atrophic effects of CP were also partially reduced by MLE. In this study, the preventive effects of MLE on the lowest potency topical glucocorticoid, hydrocortisone (HC), were investigated using animal models. METHODS: Anti-inflammatory activity of topical HC was evaluated using a 12-O-tetradecanoylphobol-13-acetate-induced skin edema model. Topical steroid induced adverse effects were evaluated using hairless mouse. RESULTS: The results showed that the anti-inflammatory activity was not altered by co-application of either MLE or hydrobase. However, co-application of MLE and 1.0% HC showed less impairment in the epidermal permeability barrier function, skin hydration, and skin surface pH compared with hydrobase. Stratum corneum integrity, evaluated by measuring trans-epidermal water loss after repeated tape stripping, showed less damage with MLE co-application. Long-term application of topical HC induced skin atrophy, measured by a reduction in skinfold and epidermal thickness and in the number of epidermal proliferating cell nucleus antigen (PCNA)-positive keratinocytes. Co-application of MLE did not affect the skinfold or epidermal thickness, but the number of PCNA-positive keratinocytes was less decreased with MLE use. CONCLUSIONS: These results suggest that co-application of MLE is effective in reducing the local adverse effects of low-potency topical glucocorticoids and supports the therapeutic efficacy of physiological lipid mixtures on skin barrier function.

Effectiveness of Topical Chia Seed Oil on Pruritus of End-stage Renal Disease (ESRD) Patients and Healthy Volunteers

BACKGROUND: Several studies have been performed to evaluate the efficacy of dietary n-3 fatty acid for patients with renal dysfunction. While about 40% to 80% of patients with end-stage renal disease (ESRD) complain about pruritus and xerosis, there are few reports on the effects of topical n-3 fatty acid on these symptoms. OBJECTIVE: In order to investigate the possible beneficial effects of topical n-3 fatty acid, oils extracted from chia (Salvia hispanica) seed were formulated into topical products, the effects of which were measured. METHODS: Five healthy volunteers having xerotic pruritus symptoms and 5 patients with pruritus caused by either ESRD or diabetes were involved in this study. A topical formulation containing 4% chia seed oils were applied for an 8-week duration. Subjective itching symptoms were assessed on a 6-point scale, as were other skin functions, namely transepidermal water loss and skin capacitance. RESULTS: After the 8 weeks of application, significant improvements in skin hydration, lichen simplex chronicus, and prurigo nodularis were observed in all patients. A similar improvement was also observed among healthy volunteers with xerotic pruritus. Improvement of epidermal permeability barrier function and skin hydration, represented by trans-epidermal water loss and skin capacitance, respectively, were also observed. No adverse effects were observed in all the tested patients and volunteers. CONCLUSION: Chia seed oil can be used as an adjuvant moisturizing agent for pruritic skin, including that of ESRD patients.

Protease and Protease-Activated Receptor-2 Signaling in the Pathogenesis of Atopic Dermatitis

Proteases in the skin are essential to epidermal permeability barrier homeostasis. In addition to their direct proteolytic effects, certain proteases signal to cells by activating protease-activated receptors (PARs), the G-protein-coupled receptors. The expression of functional PAR-2 on human skin and its role in inflammation, pruritus, and skin barrier homeostasis have been demonstrated. Atopic dermatitis (AD) is a multifactorial inflammatory skin disease characterized by genetic barrier defects and allergic inflammation, which is sustained by gene-environmental interactions. Recent studies have revealed aberrant expression and activation of serine proteases and PAR-2 in the lesional skin of AD patients. The imbalance between proteases and protease inhibitors associated with genetic defects in the protease/protease inhibitor encoding genes, increase in skin surface pH, and exposure to proteolytically active allergens contribute to this aberrant protease/PAR-2 signaling in AD. The increased protease activity in AD leads to abnormal desquamation, degradation of lipid-processing enzymes and antimicrobial peptides, and activation of primary cytokines, thereby leading to permeability barrier dysfunction, inflammation, and defects in the antimicrobial barrier. Moreover, up-regulated proteases stimulate PAR-2 in lesional skin of AD and lead to the production of cytokines and chemokines involved in inflammation and immune responses, itching sensation, and sustained epidermal barrier perturbation with easier allergen penetration. In addition, PAR-2 is an important sensor for exogenous danger molecules, such as exogenous proteases from various allergens, and plays an important role in AD pathogenesis. Together, these findings suggest that protease activity or PAR-2 may be a future target for therapeutic intervention for the treatment of AD.

Effect of Topically Applied Multi-lamellar Emulsion Containing Linoleic Acid on Experimentally Induced Comedones / 대한피부과학회지

BACKGROUND: Disturbed keratinization of the follicular infundibulum is the earliest change in comedo formation. The relative decrease in linoleic acid in the sebum could be responsible, in part, for this abnormal keratinization. OBJECTIVE: This study was conducted to evaluate the effects of topically applied multi-lamellar emulsion containing linoleic acid (MLE/LA) on experimentally induced comedones. METHODS: To induce comedo formation, 50% oleic acid (OL) in macrogol 400 was applied to the ventral surface of both ears of New Zealand white rabbits. Twenty ears of ten rabbits were randomly divided into four treatment groups (5 ears in each group). Four groups (OL only, OL and MLE/LA, OL and MLE, OL and control vehicle containing LA) were treated twice daily for 2 weeks. The relative increase in areas of the comedo was evaluated by digital image analysis. The morphologic changes around the epithelial lining of the comedo were observed by light microscopy and scanning electron microscopy. RESULTS: After 2 weeks of application, only the OL and MLE/LA combined treated group showed significantly less (by 1.23-fold, p<0.05) increase in comedo size when compared to the OL treated group (by 1.86-fold). Upon light microscopy and scanning electron microscopy examination, the MLE/LA treated ears showed a lesser degree of epidermal hyperplasia and hyperkeratosis in the follicular infundibulum compared with the OL treated ears. CONCLUSION: Topical MLE/LA might have an inhibitory effect on the formation of OL induced comedones.

The Effects of Strontium Ions on Epidermal Permeability Barrier / 대한피부과학회지

BACKGROUND: Several ions, such as calcium or magnesium ions, are reported to have regulatory effects on epidermal permeability barrier homeostasis. Recently, it has been suggested that strontium ion can play a substitutive role for calcium ion in various cellular reactions. OBJECTIVE: This study was conducted to investigate the effects of strontium ion, either alone or in combination with calcium or magnesium ions, on epidermal permeability barrier homeostasis. METHODS: Female hairless mice were used to study the effects of various ions on epidermal permeability barrier recovery. Calcium chloride solution, magnesium chloride solution or strontium chloride solution were topically applied to barrier-disrupted skin, either alone or simultaneously. Change of transepidermal water loss, which represents permeability barrier function, was measured by TEWameter and morphological change was also observed by light and electron microscopy. RESULTS: Topical application of strontium chloride solution accelerated permeability barrier recovery rate, compared with vehicle-applied skin. Magnesium chloride solution also accelerated barrier recovery rate, as reported in previous studies. Interestingly, simultaneous application of strontium and calcium ions significantly accelerated barrier recovery rate, compared to application of strontium or calcium ion alone. Nile red staining confirmed the increased neutral lipid deposition in strontium ion applied skin. Electron microscopic observation also revealed an increased lamellar body secretion in strontium ion applied skin. CONCLUSION: Strontium ion can play a regulatory role in epidermal permeability barrier homeostasis due to, at least in part, its competitive action on calcium ion for the same ion channel.

An Update of the Defensive Barrier Function of Skin

Skin, as the outermost organ in the human body, continuously confronts the external environment and serves as a primary defense system. The protective functions of skin include UV-protection, anti-oxidant and antimicrobial functions. In addition to these protections, skin also acts as a sensory organ and the primary regulator of body temperature. Within these important functions, the epidermal permeability barrier, which controls the transcutaneous movement of water and other electrolytes, is probably the most important. This permeability barrier resides in the stratum corneum, a resilient layer composed of corneocytes and stratum corneum intercellular lipids. Since the first realization of the structural and biochemical diversities involved in the stratum corneum, a tremendous amount of work has been performed to elucidate its roles and functions in the skin, and in humans in general. The perturbation of the epidermal permeability barrier, previously speculated to be just a symptom involved in skin diseases, is currently considered to be a primary pathophysiologic factor for many skin diseases. In addition, much of the evidence provides support for the idea that various protective functions in the skin are closely related or even co-regulated. In this review, the recent achievements of skin researchers focusing on the functions of the epidermal permeability barrier and their importance in skin disease, such as atopic dermatitis and psoriasis, are introduced.

An Update of the Defensive Barrier Function of Skin

Skin, as the outermost organ in the human body, continuously confronts the external environment and serves as a primary defense system. The protective functions of skin include UV-protection, anti-oxidant and antimicrobial functions. In addition to these protections, skin also acts as a sensory organ and the primary regulator of body temperature. Within these important functions, the epidermal permeability barrier, which controls the transcutaneous movement of water and other electrolytes, is probably the most important. This permeability barrier resides in the stratum corneum, a resilient layer composed of corneocytes and stratum corneum intercellular lipids. Since the first realization of the structural and biochemical diversities involved in the stratum corneum, a tremendous amount of work has been performed to elucidate its roles and functions in the skin, and in humans in general. The perturbation of the epidermal permeability barrier, previously speculated to be just a symptom involved in skin diseases, is currently considered to be a primary pathophysiologic factor for many skin diseases. In addition, much of the evidence provides support for the idea that various protective functions in the skin are closely related or even co-regulated. In this review, the recent achievements of skin researchers focusing on the functions of the epidermal permeability barrier and their importance in skin disease, such as atopic dermatitis and psoriasis, are introduced.

The Effects of Topical Glycolic Acid on the Expression of Epidermal Cytokines and Epidermal Calcium Gradient of Hairless Mice / 대한피부과학회지

BACKGROUND: Although the topical application of glycolic acid (GA) could possibly exert some effects on the normal epidermal permeability function, the exact effects and its mechanism of action have not been well documented. OBJECTIVE: This study was conducted to investigate the effects of GA on the expression of epidermal cytokines and to clarify its chelation effect on the epidermal calcium ions, which are known to control the secretion of lamellar bodies. METHODS: After topical application of 70% GA aqueous solution on the flank of hairless mice, the expression of epidermal IL-1alpha and TNF-alpha was assessed and the change of epidermal calcium ions was evaluated. RESULTS: The results could be summarized as the following: (1) real time reverse transcriptase polymerase chain reaction and immunohistochemical staining studies showed increases in mRNA and protein expression of epidermal IL-1alpha and TNF-alpha; (2) the GA reduced intracellular calcium ion concentrations in vitro and resulted in the loss of epidermal calcium gradient in vivo. CONCLUSION: These results suggest that, like iontophoresis or sonophoresis, GA could influence the skin's barrier homeostasis, possibly by lowering the epidermal calcium ions.

Comparison of the Effect of Various Chemical Peeling Agents on the Skin Barrier / 대한피부과학회지

BACKGROUND: Among the various methods for chemical peeling, it is possible to select a wide range of peeling agents for particular patients. OBJECTIVES: The objective of present study was to investigate the effects of various chemical peeling agents on the epidermal permeability barrier of hairless mice skin and to clarify the histologic alteration in epidermal structure, thus to apply in the clinical practices. METHODS: We have applied 35% and 70% glycolic acid (GA) aqueous solutions, 30% of salicylic acid (SA) solution of PEG400, Jessner's solution and 15%, 30% and 50% of trichloroacetic acid (TCA) aqueous solution to the flank of hairless mice. TEWL (trans-epidermal water loss) values were measured before and immediately after the application and 3, 6, 12 and 24 hours following treatment. Biopsy specimens were evaluated with light and electron microscopy for epidermal structural changes. RESULTS: There were no significant changes in TEWL for the GA and SA solution treated skin, regardless of their concentration. For the TCA and Jessner's solution, TEWL increased immediately after treatment and recovered the basal levels about 90% after 24 hours for Jessner's solution and low concentrated TCA solution, but did not recovered for high concentrated TCA solution. On light and electron microscopic examination, exfoliating effect was seen in every case and as for SA and Jessner's solution treated skin, keratolysis at hair follicles was also seen. Slight epidermal necrosis was seen in every case, except in GA treated skin. CONCLUSION: The present results suggest that using topical agents such as glycolic acid can induce the change in the architecture of the epidermis without disrupting the skin barrier.