Abnormal epidermal barrier in the pathogenesis of contact dermatitis. Clin Dermatol. 2012;30:335-344. [PMID: 22507049 DOI: 10.1016/j.clindermatol.2011.08.019]

Adipokine-Enriched Adipose Extract Restores Skin Barrier and Ameliorates Inflammatory Dysregulation in Atopic Dermatitis Mice

BACKGROUND

Atopic dermatitis (AD) is a chronic dermatosis with high incidence worldwide characterized by skin barrier abnormalities and immune dysregulation. Conventional therapies are usually limited by side effects and high cost. Given the antiinflammatory and repairing properties, adipokines are increasingly considered as promising therapeutic agents for dermatoses. Adipose collagen fragments (ACF), a novel adipokine-enriched product, may alleviate AD through modulating immune microenvironment and restoring skin barrier.

METHODS

ACF was extracted from adipose tissue by means of high-speed homogenization (10,000 rpm/min for 1 minute) and centrifugation (3000 g for 3 minutes). Ovalbumin-induced AD female BALB/c mice (6-week-old) were intradermally injected with 0.2 mL of ACF or phosphate-buffered saline (negative control), with normal mice being set as normal control ( n = 6). Dermatitis severity, inflammatory metrics (epidermal thickness, infiltrated mast cells, T helper cell [Th]-type cytokine expression), and skin barrier-related metrics (transepidermal water loss, skin barrier-related proteins expression) were evaluated after the AD induction period (day 50). ACF-derived bioactive components were also evaluated using proteomic analysis.

RESULTS

ACF-derived adipokines contained antiinflammatory, skin barrier- and lipid biosynthesis-related components. ACF treatment decreased dermatitis severity (6.2 ± 1.8 [ P < 0.0001]), epidermal thickness (25.7 ± 12.8 μm [ P = 0.0045]), infiltrated mast cells (31.3 ± 12.4 cells/field [ P = 0.0475]), and expression of Th-type cytokines (interferon-γ, tumor necrosis factor-α, interleukin [IL]-4, IL-4R, IL-13, and IL-17A [ P < 0.05]) in AD skins. Transepidermal water loss (29.8 ± 13.8 g/m 2 per hour [ P = 0.0306]) and skin barrier-related protein expression (filaggrin, 14,258 ± 4375 [ P = 0.0162]; loricrin, 6037 ± 1728 [ P = 0.0010]; claudin-1, 20,043 ± 6406 [ P = 0.0420]; and zonula occludens-1, 4494 ± 1114 [ P = 0.0134]) were also improved.

CONCLUSIONS

ACF improved AD in a murine model by ameliorating inflammatory dysregulation and skin barrier defects. Further validation is needed in more advanced animal models.

CLINICAL RELEVANCE STATEMENT

ACF is an injectable, adipose-derived collagen scaffold prepared from autologous harvested fat using fast and simple mechanical methods. ACF may reduce the limitations associated with health care regulatory issues and serve as a promising autologous therapeutic agent for skin disorders in clinics.

Beclomethasone loaded liposomes enriched with mucin: A suitable approach for the control of skin disorders

Inflammatory skin disorders are the fourth leading cause of chronic non-fatal conditions, which have a serious impact on the patient quality of life. Due to their treatment with conventional corticosteroids, which often result in poor therapeutic efficacy, relapses and systemic side effects from prolonged therapy, these diseases represent a global burden that negatively impacts the global economy. To avoid these problems and optimize corticosteroid benefits, beclomethasone was loaded into liposome formulations specifically tailored for skin delivery. These formulations were enhanced with mucin (0.1 and 0.5 % w/v) to further ensure prolonged formulation permanence at the site of application. The addition of 0.5 % w/v mucin resulted in the formation of small unilamellar vesicles and multicompartment vesicles. Liposomes and 1mucin-liposomes were smaller (∼48 and ∼61 nm, respectively) and more monodispersed (PI ∼ 0.14 and ∼ 0.17, respectively) than 5mucin-liposomes, which were larger (∼137 nm), slightly polydispersed (PI ∼ 0.23), and less stable during storage (4 months in the dark at 25 °C). Liposomes were negatively charged (∼ -79 mV) irrespective of their composition, and capable of incorporating high amount of beclomethasone (∼ 80 %). In vitro studies on skin fibroblasts and keratinocytes confirmed the high biocompatibility of all formulations (viability ≥ 95 %). However, the use of mucin-liposomes resulted in higher efficacy against nitric oxide production and free radical damage. Finally, topical applications using 12-O-tetradecanoylphorbol-13-acetate-injured skin in vivo experiments showed that only the mucin-enriched formulations could restore healthy conditions within 4 days, underscoring promise as a treatment for skin disorders.

Ursodeoxycholic acid alleviates atopic dermatitis-associated inflammatory responses in HaCaT and RBL-2H3 cells and DNCB/DFE-treated mice

AIMS

Ursodeoxycholic acid (UDCA) is a hydrophilic dihydroxy bile acid used for cholestatic liver disease and exhibits antioxidant, antitumor, and anti-inflammatory effects. However, its potential effects on atopic dermatitis (AD) have not been elucidated. This study aimed to evaluate the efficacy of UDCA in inhibiting the inflammatory response and alleviating lesions in AD-like mice.

MAIN METHODS

To investigate the efficacy of UDCA in AD-like inflammatory responses, tumor necrosis factor-alpha (TNF-α)- and interferon-gamma (IFN-γ)-stimulated HaCaT cells and anti-dinitrophenyl immunoglobulin E (DNP-IgE)- and human serum albumin (HSA)-stimulated RBL-2H3 cells were used to investigate the levels of inflammatory factors and their mechanisms. AD-like lesions were induced by applying DNCB/DFE to mice. The effect of UDCA administration in AD-like mice was analyzed by assessing organ weight, serum IgE and inflammatory cytokine levels, and histopathological changes using immunohistochemical and immunofluorescent staining.

KEY FINDINGS

In HaCaT cells, UDCA significantly diminished TARC, MDC, MCP-1, and IL-6 expression by inhibiting the phosphorylation of nuclear NF-κB and cytoplasmic IκB, and also increased the levels of skin barrier protein. In RBL-2H3 cells, UDCA reduced β-hexosaminidase and IL-4 levels. In AD-like mice, UDCA suppressed organ hypertrophy, ear edema, SCORAD index, DFE-specific IgE levels, inflammatory cytokine levels, skin hypertrophy, mast cell invasion, skin barrier loss, and thymic stromal lymphopoietin-positive areas.

SIGNIFICANCE

UDCA suppressed the expression of pro-inflammatory cytokines by keratinocytes and mast cells. It also alleviated atopy by suppressing symptoms without organ toxicity in AD-like mice. UDCA may be an effective and safe treatment for AD.

Infectious disease among adults with allergic contact dermatitis: a propensity score-matched case-control study

Although recent studies have hinted at associations between allergic contact dermatitis (ACD) and infectious diseases, extensive cohort analyses on the direct correlations between ACD and increased susceptibility to these infections remain limited. After analysing the ‘All of Us’ database, which includes a diverse cohort of 287 011 participants, the study identified 4854 patients with ACD. Comparisons with matched controls revealed a significant association between ACD and various infectious cutaneous comorbidities. Specifically, individuals with ACD showed a heightened risk of conditions like impetigo, scabies, cutaneous herpes simplex virus, cutaneous candidiasis, cutaneous abscess and verruca vulgaris.

Penetration rates into the stratum corneum layer: A novel quantitative indicator for assessing skin barrier function

BACKGROUND

The stratum corneum (SC), the outermost layer of the skin epidermis, acts as an effective bi-directional barrier, preventing water loss (inside-outside barrier) and entry of foreign substances (outside-inside barrier). Although transepidermal water loss (TEWL) is a widely-used measure of barrier function, it represents only inside-outside protection. Therefore, we aimed to establish a non-invasive method for quantitative evaluation of the outside-inside barrier function and visually present a skin barrier model.

MATERIALS AND METHODS

Skin barrier damage was induced by applying a closed patch of 1% sodium dodecyl sulfate to the forearms of eight participants; they were instructed to apply a barrier cream on a designated damaged area twice daily for 5 days. The SC barrier was evaluated by measuring TEWL and fluorescein sodium salt penetration rate before, immediately after, and 5 days after damage. The penetration rate was assessed using tape-stripping (TS) technique and fluorescence microscopy.

RESULTS

The rates of fluorescein sodium salt penetration into the lower layers of SC differed significantly based on the degree of skin barrier damage. The correlation between penetration rate and TEWL was weak after two rounds of TS and became stronger after subsequent rounds. Five days after skin barrier damage, the penetration rate of all layers differed significantly between areas with and without the barrier cream application.

CONCLUSION

Our findings demonstrated that the penetration rate was dependent on skin barrier conditions. The penetration rate and corresponding fluorescence images are suitable quantitative indicators that can visually represent skin barrier conditions.

Oat (Avena sativa L.) Sprouts Restore Skin Barrier Function by Modulating the Expression of the Epidermal Differentiation Complex in Models of Skin Irritation

Oats (Avena sativa L.) are used as therapeutic plants, particularly in dermatology. Despite numerous studies on their skin moisturization, anti-inflammation, and antioxidation effects, the precise molecular mechanisms of these effects are only partially understood. In this study, the efficacy of oat sprouts in the treatment of allergic contact dermatitis (ACD) was investigated, and their specific phytoconstituents and exact mechanisms of action were identified. In the in vivo ACD model, by stimulating the mitogen-activated protein kinase signaling pathway, oat sprouts increased the expression levels of proteins associated with skin barrier formation, which are produced during the differentiation of keratinocytes. In addition, in a lipopolysaccharide-induced skin irritation model using HaCaT, steroidal saponins (avenacoside B and 26-deglucoavenacoside B) and a flavonoid (isovitexin-2-o-arabinoside) of oat sprouts regulated the genetic expression of the same proteins located on the adjacent locus of human chromosomes known as the epidermal differentiation complex (EDC). Furthermore, oat sprouts showed immunomodulatory functions. These findings suggest the potential for expanding the use of oat sprouts as a treatment option for various diseases characterized by skin barrier disruption.

Macrocystis pyrifera Lipids Reduce Cytokine-Induced Pro-Inflammatory Signalling and Barrier Dysfunction in Human Keratinocyte Models

Atopic dermatitis is a chronic condition where epidermal barrier dysfunction and cytokine production by infiltrating immune cells exacerbate skin inflammation and damage. A total lipid extract from Macrocystis pyrifera, a brown seaweed, was previously reported to suppress inflammatory responses in monocytes. Here, treatment of human HaCaT keratinocytes with M. pyrifera lipids inhibited tumour necrosis factor (TNF)-α induced TNF receptor-associated factor 2 and monocyte chemoattractant protein (MCP)-1 protein production. HaCaT cells stimulated with TNF-α, interleukin (IL)-4, and IL-13 showed loss of claudin-1 tight junctions, but little improvement was observed following lipid pre-treatment. Three-dimensional cultures of HaCaT cells differentiated at the air-liquid interface showed increased MCP-1 production, loss of claudin-1 tight junctions, and trans-epidermal leakage with TNF-α, IL-4, and IL-13 stimulation, with all parameters reduced by lipid pre-treatment. These findings suggest that M. pyrifera lipids have anti-inflammatory and barrier-protective effects on keratinocytes, which may be beneficial for the treatment of atopic dermatitis or other skin conditions.

Discovery of a traditional Chinese herbal combination for the treatment of atopic dermatitis: saposhnikoviae radix, astragali radix and cnidium monnieri

Atopic dermatitis (AD) is a skin disease characterized by pruritus. The present study aimed to discover a herbal combination with anti-allergic and anti-inflammatory activities to treat AD. First, the anti-allergic and anti-inflammatory activities of herbs were evaluated by RBL-2H3 degranulation and HaCaT inflammatory models. Subsequently, the optimal proportion of herbs was determined by uniform design-response surface methodology. The effectiveness and synergistic mechanism was further verified. Cnidium monnieri (CM) suppressed β-hexosaminidase (β-HEX) release, saposhnikoviae radix (SR), astragali radix (AR), and CM inhibited the release of IL-8 and MCP-1. The optimal proportion of herbs was SR∶AR∶CM = 1: 2: 1. The in vivo experiments results indicated that the topical application of combination at high (2 ×) and low (1 ×) doses improved dermatitis score and epidermal thickness, and attenuated mast cell infiltration. Network pharmacology and molecular biology further clarified that the combination resisted AD by regulating the MAPK, JAK signaling pathways, and the downstream cytokines such as IL-6, IL-1β, IL-8, IL-10, and MCP-1. Overall, the herbal combination could inhibit inflammation and allergy, improving AD-like symptoms. The present study discovers a promising herbal combination, worthy of further development as a therapeutic drug for AD.

The link between cutaneous inflammation and cognitive impairment

Cognitive impairment is a symptom of neurological disorders, including dementia and Alzheimer's disease; and mild cognitive impairment can be a precursor of both disorders. Aged humans and animal models with other systemic disorders, such as cardiovascular diseases and diabetes, display a higher incidence of cognitive decline. Epidemiological studies have shown that the incidence of cognitive impairment also is higher in subjects with certain inflammatory skin disorders, including psoriasis and chronic eczematous dermatitis. Chronologically aged individuals exhibit increased cutaneous inflammation and elevated circulating cytokine levels, linked to alterations in epidermal function, which itself can induce cutaneous inflammation. Conversely, strategies that improve epidermal function can lower cytokine levels in both the skin and circulation. Thus, it seems likely that epidermal dysfunction could contribute, at least in part, to the development of chronic low-grade inflammation, also termed 'inflammaging', in the elderly. The evidence of cognitive impairment in patients with inflammatory dermatoses suggests a link between cutaneous inflammation and cognitive impairment. Because of the pathogenic role of epidermal dysfunction in ageing-associated cutaneous inflammation, improvements in epidermal function could be an alternative approach for mitigation of the ageing-associated decline in cognitive function.

Alterations in epidermal function in type 2 diabetes: Implications for the management of this disease

Epidermal function is regulated by numerous exogenous and endogenous factors, including age, psychological stress, certain skin disorders, ultraviolet irradiation and pollution, and epidermal function itself can regulate cutaneous and extracutaneous functions. The biophysical properties of the stratum corneum reflect the status of both epidermal function and systemic conditions. Type 2 diabetes in both murine models and humans displays alterations in epidermal functions, including reduced levels of stratum corneum hydration and increased epidermal permeability as well as delayed permeability barrier recovery, which can all provoke and exacerbate cutaneous inflammation. Because inflammation plays a pathogenic role in type 2 diabetes, a therapy that improves epidermal functions could be an alternative approach to mitigating type 2 diabetes and its associated cutaneous disorders.

Aquaporins Are One of the Critical Factors in the Disruption of the Skin Barrier in Inflammatory Skin Diseases

The skin is the largest organ of the human body, serving as an effective mechanical barrier between the internal milieu and the external environment. The skin is widely considered the first-line defence of the body, with an essential function in rejecting pathogens and preventing mechanical, chemical, and physical damages. Keratinocytes are the predominant cells of the outer skin layer, the epidermis, which acts as a mechanical and water-permeability barrier. The epidermis is a permanently renewed tissue where undifferentiated keratinocytes located at the basal layer proliferate and migrate to the overlying layers. During this migration process, keratinocytes undertake a differentiation program known as keratinization process. Dysregulation of this differentiation process can result in a series of skin disorders. In this context, aquaporins (AQPs), a family of membrane channel proteins allowing the movement of water and small neutral solutes, are emerging as important players in skin physiology and skin diseases. Here, we review the role of AQPs in skin keratinization, hydration, keratinocytes proliferation, water retention, barrier repair, wound healing, and immune response activation. We also discuss the dysregulated involvement of AQPs in some common inflammatory dermatological diseases characterised by skin barrier disruption.

The Suppressive Effect of Mamiran Cream on Atopic Dermatitis-Like Skin Lesions In Vivo

BACKGROUND

The Chinese herbal formula Mamiran cream (MMC) has been known for its ameliorative effects on diverse skin diseases, such as eczema. Atopic dermatitis (AD; eczema) is a chronic recurrent skin disease dominated by T-helper type 2-driven inflammation (Th2).

OBJECTIVE

In this study, the inhibitory effect of MMC on AD was investigated in vivo.

METHODS

An animal model was established by sensitization with 2,4-dinitrochlorobenzene (DNCB) on the skin of SD rats. Cutaneous administration of MMC was applied, and its mechanism of action was investigated via RT-PCR and IHC assay.

RESULT

Our data showed that topical application of MMC reduced the skin severity scores and alleviated the histological changes. Furthermore, immunohistochemical analysis demonstrated that MMC significantly decreased the levels of Th2 cytokine IL-5 and IL-4Ra in the skin lesion. In addition, it was demonstrated that MMC downregulated the mRNA expression of TNF-α, IL-1β, IL-6, IL-10, and TLR4. Moreover, MMC inhibited the activation of NF-κB, JNK1, and STAT6 pathways in skin lesions.

CONCLUSIONS

Our findings suggest that MMC exhibits the inhibitory effect on AD, suggesting that MMC may be a potential therapeutic agent for this atopic disorder.

Risk factors for periorbital dermatitis in patients using dorzolamide/timolol eye drops

This study assessed the clinical risk factors for periorbital dermatitis (PD) after using dorzolamide/timolol eye drops in a total of 1282 glaucoma patients. Both the PD(+) group and the PD(−) group were evaluated using clinical data such as age, sex, dosing duration, presence of benzalkonium chloride (BAK) in the formulation, ocular surgery history (e.g. cataract or glaucoma operations), height, weight, personal history of systemic hypertension, smoking, alcohol consumption, intraocular pressure, best-corrected visual acuity (BCVA), central corneal thickness, axial length, and visual field index (VFI). Univariate analyses showed that shorter dosing duration, higher rate of BAK-included cases, worse BCVA, worse VFI, more systemic hypertension history, and more ocular surgery history were more associated with the PD(+) group than the PD(−) group. The BAK(−) group showed a lower PD rate than the BAK-included group, which was supported by the Kaplan–Meier analysis (log-rank test, p = 0.0014). Multivariate analyses revealed that the probability of PD increased by 8 times if they had a history of ocular surgery and increased by 2.3% when the VFI decreased by 1% (Cox’s hazard regression test, p < 0.001). Therefore, a preservative-free dorzolamide/timolol can benefit the subjects for those who had ocular surgery or who have worse VFI.

Molecular perspective of efficiency and safety problems of chemical enhancers: bottlenecks and recent advances

Chemical penetration enhancer (CPE) is a preferred approach to improve drug permeability through the skin, due to its unique advantages of simple use and high compatibility. However, CPEs efficiency and safety problems frequently arise, which greatly restrains the further application in transdermal drug delivery systems (TDDS). To get access to the root of problems, the efficiency and safety of CPEs are reviewed especially from molecular perspectives, which include (1) the possible factors of CPEs low efficiency; (2) the possible contribution of CPEs in the evolution of safety problems such as skin irritation and allergic reaction; (3) the interactive relationship between CPEs efficiency and safety, as well as the bottlenecks of achieving their balance. More importantly, based on these, recent advances are summarized in improving efficiency or safety of CPEs, which offers a guidance of rationally selecting CPEs in future research.

Epidemics of Dermatitis

Allergic contact dermatitis (ACD) remains a globally prevalent disease for both children and adults. The silent ACD epidemic continues to be fueled by the introduction of novel allergens in industrial and household products and the continued presence of known allergens. In 1997, Allan Dillarstone noted a sinusoidal pattern to epidemics when allergenic preservatives were replaced by alternative chemicals within the market, which then similarly increased in allergenicity. A call for public health vigilance and prevention initiatives is needed to intervene in the ACD epidemic.

Strategies to Develop a Suitable Formulation for Inflammatory Skin Disease Treatment

Skin barrier functions, environmental insults, and genetic backgrounds are intricately linked and form the basis of common inflammatory skin disorders, such as atopic dermatitis, psoriasis, and seborrheic dermatitis, which may seriously affect one’s quality of life. Topical therapy is usually the first line of management. It is believed that successful topical treatment requires pharmaceutical formulation from a sufficient dosage to exert therapeutic effects by penetrating the stratum corneum and then diffusing to the target area. However, many factors can affect this process including the physicochemical properties of the active compound, the composition of the formulation base, and the limitations and conditions of the skin barrier, especially in inflammatory skin. This article briefly reviews the available data on these issues and provides opinions on strategies to develop a suitable formulation for inflammatory skin disease treatment.

Hand Dermatitis in the Time of COVID-19: A Review of Occupational Irritant Contact Dermatitis

Occupational contact dermatitis accounts for 95% of all cases of occupational skin disease with irritant contact dermatitis (ICD) constituting 80% to 90% of these cases. Health care workers, hairdressers, and food service workers are typically most affected by occupational ICD of the hands as these occupations require frequent hand hygiene and/or prolonged exposure to water, also known as "wet work." In the context of the current COVID-19 pandemic, frequent hand hygiene has become a global recommendation for all individuals, and new workplace guidelines for hand sanitization and surface sterilization are affecting occupations not previously considered at risk of excessive wet work including grocery or retail workers, postal workers, sanitization workers, and others. In this review, we discuss the etiology and pathogenesis of occupational ICD with additional focus on treatment and interventions that can be made at an institutional and even national level for education and prevention of ICD resulting from frequent hand hygiene.

Prevalence of Skin Reactions and Self-Reported Allergies in 5 Countries with Their Social Impact Measured through Quality of Life Impairment

Background: The prevalence of allergies increases worldwide. Allergies may increase the risk of skin reactions. Objective: To evaluate the prevalence of allergies and skin reactions in the adult population, the strength of their relationship, and their impact on the quality of life. Methods: An online survey was conducted in a representative population of 11,067 adults from China, USA, Brazil, Russia, and France. Results: Overall, 35.6% of respondents reported having allergies, they were predominantly fair-skinned women, and younger than responders reporting no allergy. Among patients reporting allergies, 68.6% declared that their allergy makes their skin reacts. A strong association between allergy and major skin reactions was observed, which were associated with skin discomforts such as itching, burning, and pain. Skin discomforts were associated with an increased risk of quality of life alteration. Conclusions: Quantifying the prevalence and the association of allergies with skin reactions and discomfort sensations is critical to evaluating the impact on quality of life. Since skin barrier alteration is hypothesized as a risk factor and a route of sensitization for allergy development, the daily use of topical treatments, such as moisturizers, could help prevent allergic skin reactions, discomfort and impaired quality of life in individuals with an altered skin barrier.

Topical Applications of a Novel Emollient Inhibit Inflammation in Murine Models of Acute Contact Dermatitis

The benefits of emollients for eczematous dermatitis and psoriasis have been thought to be due to the improvements in epidermal function, including epidermal permeability barrier, stratum corneum hydration, and stratum corneum pH. We determined here whether emollient can direct inhibit cutaneous inflammation. Ear inflammation was induced by topical application of either 12-O-tetradecanoylphorbol-13-acetate (TPA) or 1-fluoro-2,4-dinitrofluorobenzene (DNFB). Either 1% hydrocortisone cream or the novel emollient was applied to the right ear of the mice 45 min and 2 hours after TPA or DNFB application. The untreated left ear served as untreated controls. Both ear weight and ear thickness were measured 24 hours after TPA and DNFB application. Topical applications of either hydrocortisone cream or emollient significantly decreased both ear thickness and ear weight in comparison to untreated controls. In DNFB model, hydrocortisone significantly lowered expression levels of mRNA for IL-1α, IL-1β, and TNFα, while the emollient markedly decreased expression levels of IL-1α and TNFα mRNA. In TPA model, both hydrocortisone and emollient significantly decreased expression levels of IL-1α, IL-1β, IL-6, and TNFα mRNA. In parallel, inflammatory infiltration was also reduced by topical applications of either hydrocortisone or emollient. These results demonstrate that this novel emollient can directly inhibit cutaneous inflammation in murine models of both acute irritant contact dermatitis and acute allergic contact dermatitis. However, whether this emollient could also alleviate eczematous dermatitis in humans remains to be explored.

Topical Applications of a Heparinoid-Containing Product Attenuate Glucocorticoid-Induced Alterations in Epidermal Permeability Barrier in Mice

INTRODUCTION

Either systemic or topical glucocorticoids (GCs) can cause significant adverse effects on cutaneous structure and function. Although some products and ingredients can improve GC-induced abnormalities in epidermal permeability barrier, the efficacy is moderate. Prior studies in normal mice showed that topical applications of a heparinoid-containing product, Hirudoid® cream, improve epidermal barrier function by upregulation of epidermal proliferation, expression of mRNA for epidermal differentiation, and lipid production.

OBJECTIVE

The objective of this study was to assess whether topical applications of this product could prevent GC-induced changes in epidermal function in murine skin.

MATERIALS AND METHODS

One group of C57BL/6J mice was treated topically with 0.05% clobetasol propionate twice daily for 6 days, while another group was treated topically with Hirudoid® cream 30 min after each application of clobetasol propionate. Untreated mice served as normal controls. Transepidermal water loss (TEWL) rates, stratum corneum hydration, and skin surface pH were measured using respective probes connected to an MPA5 physiology monitor. qPCR was used to measure the expression levels of mRNA for keratinocyte differentiation-related proteins and lipid synthetic enzymes.

RESULTS

Co-applications of Hirudoid® cream with GC minimally, but significantly, increased skin thickness in comparison to GC treatment alone (p < 0.05), in parallel with increased expression levels of mRNA for PCNA in both the dermis and the epidermis. Moreover, Hirudoid® cream largely prevented GC-induced elevation in basal TEWL (p < 0.001) and delay in barrier recovery (p < 0.05), accompanied by upregulation in the expression levels of mRNA for epidermal involucrin, HMGCoA, and SPT1. However, both stratum corneum hydration and skin surface pH were comparable in the skin treated with GC alone versus GC + Hirudoid® cream.

CONCLUSION

Topical heparinoid-containing product can partially prevent GC-induced alterations in some epidermal functions.

Evaluation of hand hygiene and onset of hand eczema after the outbreak of SARS-CoV-2 in Munich

BACKGROUND

Since the outbreak of SARS-CoV-2, authorities have preached the importance of personal hygiene, including hand washing and disinfection.

OBJECTIVE

To evaluate changes in the frequency of hand washing and hand care, the onset of hand eczema (HE) and risk factors associated with HE since the outbreak of SARS-CoV-2 in Munich in January 2020.

MATERIALS & METHODS

All dermatologic outpatients at the university hospital between April 6 and April 19 were asked to complete a structured questionnaire.

RESULTS

Data of 512 patients with a median age of 49 years (243 females, 267 males) were analysed. The frequency of hand washing and hand disinfection increased after the outbreak of SARS-CoV-2 (p < 0.001, respectively). While symptoms associated with HE were reported by 29.9% (149/499) of patients, the actual diagnosis of HE was reported less frequently by 11.2% (53/473) with a median duration of 120 days. Frequent hand disinfection (p = 0.039), atopic dermatitis (p = 0.006) and young age (p = 0.0499) were identified as risk factors for symptoms of HE. Hand care was performed more frequently during the pandemic than before (p < 0.001). A high frequency of hand care during the pandemic was not significantly associated with symptoms of HE (p = 0.172), but was associated with self-recognition of HE symptoms (p = 0.002).

CONCLUSION

After the outbreak of SARS-CoV-2, the frequency of hand hygiene measures increased. A considerably high prevalence of HE symptoms was associated with frequent hand disinfection, atopic dermatitis and young age. Awareness of HE should be raised in order for preventive measures to be taken earlier.

Assessment of the different skin sensitization potentials of irritants and allergens as single substances and in combination using the KeratinoSens assay

BACKGROUND

People are exposed to mixtures containing allergens and irritants often causing contact dermatitis. Therefore, regulatory authorities require systematic information on the effects of mixtures on the sensitization threshold. In this study a moderate (cinnamal) and a weak (ethylene glycol dimethacrylate) allergen were combined with irritants covering different mechanisms of action (sodium dodecyl sulfate, salicylic acid, and α-pinene). For a systematic approach, the single substances were initially tested using the KeratinoSens assay. Thereafter, each allergen was combined with noncytotoxic concentrations of the irritants.

METHOD

The KeratinoSens assay was applied for the single substances according to OECD (Organisation for Economic Co-operation and Development) Test Guideline 442D. Based on these results, three noncytotoxic concentrations of the irritants were selected and applied simultaneously with 12 concentrations of the allergens to the KeratinoSens cells. Sensitization threshold and cytotoxicity were measured and compared with the individual testing.

RESULTS

The combinations of allergens and irritants differed from the effects of the single substances and lowered the sensitization threshold. The quantitative approach allowed a clear description of the changes which varied by factors between 1.1 and 10.3.

CONCLUSIONS

Overall, the allergen was the prominent compound in the mixture and its nature appeared to determine the degree of the response.

Multiomics Integration in Skin Diseases with Alterations in Notch Signaling Pathway: PlatOMICs Phase 1 Deployment

The high volume of information produced in the age of omics was and still is an important step to understanding several pathological processes, providing the enlightenment of complex molecular networks and the identification of molecular targets associated with many diseases. Despite these remarkable scientific advances, the majority of the results are disconnected and divergent, making their use limited. Skin diseases with alterations in the Notch signaling pathway were extensively studied during the omics era. In the GWAS Catalog, considering only studies on genomics association (GWAS), several works were deposited, some of which with divergent results. In addition, there are thousands of scientific articles available about these skin diseases. In our study, we focused our attention on skin diseases characterized by the impairment of Notch signaling, this pathway being of pivotal importance in the context of epithelial disorders. We considered the pathologies of five human skin diseases, Hidradenitis Suppurativa, Dowling Degos Disease, Adams-Oliver Syndrome, Psoriasis, and Atopic Dermatitis, in which the molecular alterations in the Notch signaling pathway have been reported. To this end, we started developing a new multiomics platform, PlatOMICs, to integrate and re-analyze omics information, searching for the molecular interactions involved in the pathogenesis of skin diseases with alterations in the Notch signaling pathway.

Skin bioengineering in the diagnosis of occupational protein contact dermatitis

Protein contact dermatitis (PCD) often presents as chronic hand eczema (CHE) with an immediate hypersensitivity to protein proved by a positive skin prick test or by the presence of specific immunoglobulin E. This is frequently induced by occupational exposure to proteins in food workers, farmers, animal breeders, veterinarians and healthcare professionals. While skin barrier impairment is crucial in the pathogenesis of PCD, methods to assess skin barrier function such as trans-epidermal water loss and stratum corneum hydration are not widely used in clinical settings. We describe the diagnostic workup of occupational PCD due to Argentinean shrimps and discuss how the use of skin bioengineering methods including assessment of corneocytes morphology by Scanning Electron Microscopy provides with insightful information on skin barrier function. Diagnosis of PCD is time-consuming and a multidisciplinary team contributes to early diagnosis and proper occupational rehabilitation.

Morphology-dependent titanium dioxide nanoparticle-induced keratinocyte toxicity and exacerbation of allergic contact dermatitis

Titanium dioxide (TiO₂) nanoparticles are commonly found in consumer products, such as sunscreens, and human dermal exposures are relatively high. Research suggests potential differences in the toxicity of anatase and rutile crystalline forms of TiO₂. Additionally, transition metal dopants are frequently used to enhance physicochemical properties of TiO₂, and the toxicity of these nanoparticles are not extensively studied. Therefore, this work examined the keratinocyte toxicity and in vivo skin allergy responses after treatment with 30 nm anatase, 30 nm rutile, or <100 nm Mn-doped TiO₂ nanoparticles. After a 24-hour exposure, there were no differences in keratinocyte cytotoxicity; however, Mn-doped TiO₂ nanoparticles induced significant in vitro ROS generation and in vivo skin swelling responses in a model of allergic contact dermatitis.

Modulators of the endocannabinoid system influence skin barrier repair, epidermal proliferation, differentiation and inflammation in a mouse model

Endocannabinoids (ECs) are important regulators of cell signalling. Cannabinoid receptors are involved in keratinocyte proliferation/differentiation. Elevation of the endogenous cannabinoid tone leads to strong anti-inflammatory effects. Here, we explored the influence of endocannabinoid system (ECS) modulators on skin permeability barrier repair, epidermal proliferation, differentiation and inflammation in hairless mice. We used WOBE440, a selective fatty acid amide hydrolase (FAAH) inhibitor, WOL067-531, an inhibitor of endocannabinoid reuptake with no relevant FAAH activity, which both signal via cannabinoid receptor-1 and cannabinoid receptor-2 (CB-1R and CB-2R) and compared them to WOBE15 which signals via CB-2R. Barrier disruption and skin irritation were induced by tape stripping or by sodium dodecyl sulphate (SDS) patch testing. Immediately after barrier disruption, 30 μL of 0.5% WOBE440, WOL067-531 and WOBE15 solutions or the vehicle was applied topically. Barrier repair was monitored by transepidermal water loss at 1.5, 3, 5 and 7 hours. We found that barrier repair was significantly delayed by WOL067-531. A tendency for a delay was noticed for WOBE440, whereas for WOBE15, no effect was observed. Immunohistology showed that the tape-stripping-induced increase in epidermal proliferation and filaggrin expression was significantly reduced by topical applications of WOL067-531 and WOBE440, but not by WOBE15. Also, the SDS-induced inflammation, as determined by the number of inflammatory cells, was reduced by WOL067-531 and WOBE440. In summary, we showed that WOL067-531 exhibits a significant effect on skin barrier repair, epidermal proliferation/differentiation and inflammation.

Role of Antimicrobial Peptides in Skin Barrier Repair in Individuals with Atopic Dermatitis

Atopic dermatitis (AD) is a common chronic inflammatory skin disease that exhibits a complex interplay of skin barrier disruption and immune dysregulation. Patients with AD are susceptible to cutaneous infections that may progress to complications, including staphylococcal septicemia. Although most studies have focused on filaggrin mutations, the physical barrier and antimicrobial barrier also play critical roles in the pathogenesis of AD. Within the physical barrier, the stratum corneum and tight junctions play the most important roles. The tight junction barrier is involved in the pathogenesis of AD, as structural and functional defects in tight junctions not only disrupt the physical barrier but also contribute to immunological impairments. Furthermore, antimicrobial peptides, such as LL-37, human b-defensins, and S100A7, improve tight junction barrier function. Recent studies elucidating the pathogenesis of AD have led to the development of barrier repair therapy for skin barrier defects in patients with this disease. This review analyzes the association between skin barrier disruption in patients with AD and antimicrobial peptides to determine the effect of these peptides on skin barrier repair and to consider employing antimicrobial peptides in barrier repair strategies as an additional approach for AD management.

Dead Sea minerals: New findings on skin and the biology beyond

BACKGROUND

Therapeutic effects of Dead Sea (DS) minerals are well established, and their unique combination is analysed and reported. DS water (DSW) is a key source for DS minerals, and various studies report the capability of DSW to alleviate symptoms of different skin disorders and to contribute to skin maintenance. However, the biological mechanisms beyond reported effects are not fully understood yet.

OBJECTIVE

To elucidate the effect of topically applied DSW via the expression of different skin biomarkers related to barrier function, homeostasis, inflammation and irritation.

METHODS

In vitro skin equivalents and ex vivo human skin organ culture were used to assess the biological effects of DSW. Epidermal barrier protein expression and DSW ions transdermal penetration were analysed on skin equivalents. β-endorphin secretion was tested on human skin organ culture. The capability of DSW to protect against skin inflammation and irritation was tested on ex vivo human skin organ culture by lipopolysaccharides and sodium dodecyl sulphate addition, respectively.

RESULTS

Topical application of DSW encouraged the expression of the barrier-related proteins: filaggrin, involucrin and transglutaminase, while transdermal penetration of calcium ions was not detected. Additionally, DSW application had increased skin secretion of β-endorphin and attenuated the expression of inflammatory and irritation-related cytokines.

CONCLUSIONS

This study reports new findings of DSW effects on skin. Signalling pathway activation is proposed as a key step that may result in a vast range of proven biological activities following skin exposure to DS minerals, and specifically DSW.

Pleiotropic Role of Notch Signaling in Human Skin Diseases

Notch signaling orchestrates the regulation of cell proliferation, differentiation, migration and apoptosis of epidermal cells by strictly interacting with other cellular pathways. Any disruption of Notch signaling, either due to direct mutations or to an aberrant regulation of genes involved in the signaling route, might lead to both hyper- or hypo-activation of Notch signaling molecules and of target genes, ultimately inducing the onset of skin diseases. The mechanisms through which Notch contributes to the pathogenesis of skin diseases are multiple and still not fully understood. So far, Notch signaling alterations have been reported for five human skin diseases, suggesting the involvement of Notch in their pathogenesis: Hidradenitis Suppurativa, Dowling Degos Disease, Adams-Oliver Syndrome, Psoriasis and Atopic Dermatitis. In this review, we aim at describing the role of Notch signaling in the skin, particularly focusing on the principal consequences associated with its alterations in these five human skin diseases, in order to reorganize the current knowledge and to identify potential cellular mechanisms in common between these pathologies.

The aryl hydrocarbon receptor as a target of environmental stressors - Implications for pollution mediated stress and inflammatory responses

The aryl hydrocarbon receptor (AHR) is a ligand-activated transcription factor regulating the expression of genes, for instance encoding the monooxygenases cytochrome P450 (CYP) 1A1 and CYP1A2, which are important enzymes in metabolism of xenobiotics. The AHR is activated upon binding of polycyclic aromatic hydrocarbons (PAHs), persistent organic pollutants (POPs), and related ubiquitous environmental chemicals, to mediate their biological and toxic effects. In addition, several endogenous and natural compounds can bind to AHR, thereby modulating a variety of physiological processes. In recent years, ambient particulate matter (PM) associated with traffic related air pollution (TRAP) has been found to contain significant amounts of PAHs. PM containing PAHs are of increasing concern as a class of agonists, which can activate the AHR. Several reports show that PM and AHR-mediated induction of CYP1A1 results in excessive generation of reactive oxygen species (ROS), causing oxidative stress. Furthermore, exposure to PM and PAHs induce inflammatory responses and may lead to chronic inflammatory diseases, including asthma, cardiovascular diseases, and increased cancer risk. In this review, we summarize findings showing the critical role that the AHR plays in mediating effects of environmental pollutants and stressors, which pose a risk of impacting the environment and human health.

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PAHs present on ambient air pollution particles are ligands of the cellular AHR.

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AHR-dependent induction of CYP1, AKR, NOX and COX-2 genes can be a source of ROS generation.

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AHR signaling and NRF2 signaling interact to regulate the expression of antioxidant genes.

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Air pollution and ROS can affect inflammation, which is partially triggered by AHR and associated immune responses.

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Skin, lung, and the cardiovascular system are major target sites for air pollution-induced inflammation.

Casearia decandra leaves present anti-inflammatory efficacy in a skin inflammation model in mice

ETHNOPHARMACOLOGICAL RELEVANCE

Casearia decandra (guaçatonga) is popularly used as an anti-inflammatory. We investigated the antioxidant and anti-inflammatory effect of C.decandra leaves (CdE) ethanolic extract and of the rutin standard (present in the CdE).

MATERIALS AND METHODS

Male adult Swiss mice were used (25-30 g; 5-6 animals by a group). CdE phytochemical analysis was performed by HPLC method. The antioxidant potential of CdE and rutin was assessed by different methods. Topical anti-inflammatory effect of CdE (0.001-1mg/ear) and rutin (0.003-0.03mg/ear) was evaluated by ear edema formation and inflammatory cells infiltration (MPO activity and histology) on a skin inflammation model induced by topical application of croton oil (1mg/ear).

RESULTS

Rutin (27.81 ± 1.11 mg/g) was identified in CdE by HPLC analysis. The required amounts of CdE, rutin and ascorbic acid to reduce the initial concentration of radical DPPH by 50% (IC₅₀) were 7.77 (6.31-9.57) μg/mL, 3.62 (3.26-4.01) μg/mL and 3.74 (3.37-4.14) μg/mL with a radical DPPH reduction of 91 ± 1.2%, 91 ± 0.5%, and 96 ± 0.44% (at 30 μg/mL), respectively. Moreover, CdE and rutin presented H₂O₂ scavenging activity with H₂O₂ levels reduction of 41 ± 7% and 46 ± 6%, respectively and SOD-like activity of 60 ± 4% and 51 ± 14%, respectively. On the other hand, just rutin presented nitric oxide scavenging activity of 54 ± 6%. CdE and rutin topically applied inhibited the ear edema with a maximum inhibition of 70 ± 5% (1 mg/ear) and 78 ± 10% (0.03 mg/ear), respectively. Treatments reduced the MPO activity (42 ± 4% to CdE; 1mg/ear and 30 ± 8% to rutin; 0.03 mg/ear). Histologically, the topical treatments also reduced the dermis thickness and the inflammatory cells infiltration.

CONCLUSION

We demonstrated the antioxidant and anti-inflammatory effect of C.decandra leaves and rutin. Its antioxidant potential may contribute to inflammatory process attenuation, supporting the C.decandra leaves used as a promising alternative in the therapy of the inflammatory diseases.

Atopic Dermatitis in Adults

Atopic dermatitis (AD) was once thought to be a benign childhood disease that remitted with increasing age. However, recent studies have transformed the understanding of AD, particularly in adult patients. AD is common in adults and can lead to substantial disability by negatively affecting sleep, mental health, and quality of life. There seem to be different genetic, immunologic, and epidemiologic risk factors for AD in adults than in children. This article examines the pathophysiology, epidemiology, heterogeneous clinical presentation, burden, diagnosis, and treatment of adult AD.

Adult-Onset Atopic Dermatitis: Characteristics and Management

Recent epidemiological studies found the US prevalence of atopic dermatitis in adults to be approximately 7%. In particular, one in four adults with atopic dermatitis report adult onset of their disease. Adult-onset compared to child-onset atopic dermatitis is associated with distinct risk factors, lesional distribution and morphology, associated signs, genetics, and comorbidities. Adult-onset atopic dermatitis is a clinical diagnosis, and must be distinguished from other entities in the differential diagnosis, e.g., allergic contact dermatitis and cutaneous T-cell lymphoma. Further research is necessary to better understand the pathogenesis and optimal treatment approaches in adult-onset/recurrent atopic dermatitis.

Palmitoyl Acyltransferase Activity of ZDHHC13 Regulates Skin Barrier Development Partly by Controlling PADi3 and TGM1 Protein Stability

Deficiency of the palmitoyl-acyl transferase ZDHHC13 compromises skin barrier permeability and renders mice susceptible to environmental bacterial infection and inflammatory dermatitis. It had been unclear how the lack of ZDHHC13 proteins resulted in cutaneous abnormalities. In this study, we first demonstrate that enzymatic palmitoylation activity, rather than protein scaffolding, by ZDHHC13 is essential for skin barrier integrity, showing that knock-in mice bearing an enzymatically dead DQ-to-AA ZDHHC13 mutation lost their hair after weaning cyclically, recapitulating knockout phenotypes of skin inflammation and dermatitis. To establish the ZDHHC13 substrates responsible for skin barrier development, we employed quantitative proteomic approaches to identify protein molecules whose palmitoylation is tightly controlled by ZDHHC13. We identified over 300 candidate proteins that could be classified into four biological categories: immunological disease, skin development and function, dermatological disease, and lipid metabolism. Palmitoylation of three of these candidates-loricrin, peptidyl arginine deiminase type III, and keratin fiber crosslinker transglutaminase 1-by ZDHHC13 was confirmed by biochemical assay. Palmitoylation was critical for in vivo protein stability of the latter two candidates. Our findings reveal the importance of protein palmitoylation in skin barrier development, partly by promoting envelope protein crosslinking and the filaggrin processing pathway.

The benefit of a ceramide-linoleic acid-containing moisturizer as an adjunctive therapy for a set of xerotic dermatoses

Atopic dermatitis (AD), chronic eczema, and pruritus hiemalis are a set of prevalent chronic xerotic skin disorders that share clinical features such as dryness, scales, and pruritus. A ceramide deficiency and defective epidermal functions are common in these diseases. This study was designed to assess the effect of ceramide-linoleic acid (LA-Cer)-containing moisturizer as an adjunctive therapy in the treatment of AD, chronic eczema, and pruritus hiemalis. In a 2-month study, patients with one of these three diseases were divided into two groups. The control group was treated with mometasone furoate (0.1%) cream (MF), whereas the treatment group received 0.1% MF in combination with an LA-Cer-containing moisturizer. Capacitance and transepidermal water loss were measured in normal and lesional skin, along with Eczema Assessment Severity Index and pruritus scores at Weeks 0, 2, 4, and 8. The results showed that tropical applications of an LA-Cer-containing moisturizer in combination with a topical glucocorticoid accelerated the reestablishment of epidermal permeability barrier and the amelioration of pruritus in patients with AD and pruritus hiemalis. However, it did not provide the same effect for chronic eczema. Thus, the efficacy of this combination therapy for this set of xerotic disorders requires further evaluation.

Novel Human Full-Thickness Three-Dimensional Nonkeratinized Mucous Membrane Model for Pharmacological Studies in Wound Healing

INTRODUCTION

Efforts are increasingly aiming to develop in vitro models that can provide effective alternatives to in vivo experiments. The main aim of this study was the establishment of an in vitro model of the nonkeratinized mucous membrane that can be used as a standardized tool to evaluate biological and therapeutic effects of pharmaceuticals for mucosal wound healing.

METHODS

We established a full-thickness in vitro model of the nonkeratinized mucous membrane. While histological examination was performed to assess morphological characteristics, we utilized gene expression profiling using microarray and qRT-PCR analyses to identify molecular effects of treatment with a dexpanthenol-containing ointment after laser wounding.

RESULTS

Performing histological and immunofluorescence analyses we proved that our model mimics the two distinctive layers of the mucous membrane - the stratified squamous epithelium and the lamina propria. We used this model to investigate molecular effects of a dexpanthenol-containing ointment that is commonly used for the wound treatment of mucous membranes. For that purpose, our model exhibits a unique feature in that dexpanthenol and proliferation-enhancing additives that may interfere with our studies are not required for the maintenance of the model culture. After setting standardized lesions with a nonsequential fractional ultrapulsed CO2 laser, topical treatment with the dexpanthenol-containing ointment enhanced wound closure in the model compared to placebo and untreated controls. Furthermore, microarray analysis revealed that the treatment of the laser-wounded model with the dexpanthenol-containing ointment evoked an upregulated expression of various genes related to accelerated wound healing.

CONCLUSION

Overall, we verified that this novel mucous membrane model can be utilized in future to monitor ex vivo effects of various topical therapies on mucosa morphology, physiology, and gene expression. Our findings confirm the potential of the model as an in vitro tool for the replacement of pharmacological in vivo studies regarding mucosal wound healing.

Transient epidermal barrier deficiency and lowered allergic threshold in filaggrin-hornerin (FlgHrnr-/- ) double-deficient mice

BACKGROUND

Filaggrin (Flg) and hornerin (Hrnr) share similar structural and functional features. Both proteins have been implicated as essential proteins for skin barrier maintenance. Loss-of-function mutations of these genes constitute a risk factor for atopic dermatitis and eczema-related asthma. Furthermore, both FLG and HRNR protein levels are downregulated in patients with atopic dermatitis. Thus, mice deficient for Flg and Hrnr provide a novel model to study skin barrier impairment and the susceptibility for cutaneous inflammation.

METHODS

By using appropriate targeting vectors and breeding strategies, we established a homozygous FlgHrnr double-deficient (FlgHrnr^-/- ) mouse model lacking both genes including the intergenomic sequence.

RESULTS

Neonates appeared normal, but developed a transient scaly phenotype with overall flaky appearance, but no overt skin phenotype in adulthood, thereby reflecting a subclinical barrier defect seen in humans. Structurally, FlgHrnr^-/- mice displayed a markedly reduced granular layer and a condensed cornified layer. Functionally, FlgHrnr^-/- mice showed permeability abnormalities and metabolic aberrations regarding the production of natural moisturizing factors (NMFs) in the stratum corneum. Surprisingly, although the immune system revealed no aberrations under steady-state conditions, FlgHrnr^-/- mice are predisposed to mount an allergic contact dermatitis, especially at hapten threshold levels eliciting allergic reactions.

CONCLUSIONS

Together, our FlgHrnr^-/- mouse model nicely reflects the epicutaneous sensitization susceptibilities and inflammatory reactions to environmental insults in humans with impaired skin barrier functions.

Comorbidities and the impact of atopic dermatitis

OBJECTIVE

Atopic dermatitis (AD) is a chronic pruritic inflammatory skin disease with substantial patient and population burdens. A number of comorbid health problems occur in patients with AD, aside from the cutaneous signs and symptoms. This review summarizes recent developments in the burden and comorbidities of AD.

DATA SOURCES

Literature review.

STUDY SELECTIONS

Nonsystematic.

RESULTS

Different aspects of AD, such as chronic pruritus, psychosocial distress, and inflammation, can lead to anxiety, depression, or suicidality. Atopic dermatitis is associated with and may predispose to higher risk of other atopic disorders, including asthma, hay fever, food allergy, and eosinophilic esophagitis. Persons with AD appear to be at higher risk for infectious and cardiovascular risk.

CONCLUSION

Atopic dermatitis is associated with substantial burden and comorbidities. Identifying AD comorbidities is essential for proper disease management and improving overall patient outcomes.

Prevalence of Atopic Dermatitis Criteria among Textile Workers with Occupational Allergic Contact Dermatitis and Effects of Having Atopic Dermatitis on Contact Antigenic Diversity

Objectives:

Contact dermatitis (CD) is a common skin disease. Occupational contact dermatitis (OCD) is the most frequently seen occupational skin disease and includes both occupational allergic CD (OACD) and occupational irritant CD (OICD). One of the most common sources of OACD is textile products. Individuals with atopic dermatitis (AD) have an increased risk for development of allergic contact dermatitis (ACD). However, the role of AD in the etiopathogenesis of the development of OACD among textile industry workers is not well known. The aim of the present study was to determine the prevalence of AD among textile workers with OACD and to analyze contact antigenic diversity between the workers with and without AD.

Methods:

A prospective, cross-sectional study was conducted with 352 textile workers who had previously been diagnosed with OACD. The patients were questioned and examined with respect to AD criteria, demographic features, disease duration, duration of employment until first symptoms, phototype, workplace (subsectors), and location of lesions at control visits. Immediate skin test reactivity was evaluated with a commercial skin prick test panel. The data obtained and the patients’ previously recorded patch test results were compared in OACD groups with and without a diagnosis of AD. The results were statistically evaluated with a significance level of p value <0.05.

Results:

The study population consisted of 124 males and 227 females. The mean age was 35.69±13.65 years. The most commonly seen employment duration, phototype, subsector, and location were 4 to 8 months (26.14%), 9 to 12 months (34.66%), Fitzpatrick type-III (37.50%), dyeing (33.52%), and exclusively the hands (60.51%), respectively. In all, 193 patients (54.83%) met the criteria for the diagnosis of AD. In the OACD group with AD, there was a significant number with 4 major and 16 minor criteria, as well as positivity for 14 contact allergens.

Conclusion:

Most AD criteria, or a diagnosis of AD, are highly detectable among workers with textile-related OACD. The results for patch test allergens may be significantly higher than those of individuals without AD. Textile workers with AD should be warned about the possibility of the early development of OACD.

The Role and Diagnosis of Allergic Contact Dermatitis in Patients with Atopic Dermatitis

Patients with atopic dermatitis (AD) have increased penetration of allergens, immune dysregulation (including shared cytokine pathways), and frequent use of emollients and topical medications, all of which may predispose toward developing allergic contact dermatitis (ACD). Recent systematic reviews have suggested that ACD is a significant clinical problem in both children and adults with AD. While this remains controversial, ACD remains an important comorbidity and potential exacerbant of AD in clinical practice. Common relevant allergens, include lanolin, neomycin, formaldehyde, sesquiterpene lactone mix, compositae mix, and fragrances that are commonly found in AD patients' personal care products. We herein review the clinical scenarios where patch testing is indicated in AD. In addition, we review the contraindications, preferred patch-testing series, pitfalls, and challenges determining the relevance of positive patch-test reactions in AD patients.

Protease-mediated Inflammation: An In Vitro Human Keratinocyte-based Screening Tool for Anti-inflammatory Drug Nanocarrier Systems

Background:

Refined encapsulation approaches in dermatotherapy gain increased interest. There is need of reproducible in vitro systems representing disease features to screen drug delivery systems for preclinical assessment. Inflammatory human skin diseases are commonly accompanied by abnormal epidermal differentiation and barrier impairment. Serine proteases (SPs) and their inhibitors play a critical role in such dysfunctional differentiation. SPs also initiate cellular pathways via activation of protease-activated receptors, which contribute to inflammation. Thus, function and activity of SPs should be considered for the design of new therapies of such disorders.

Objectives:

Herein, we established a novel simplified cell culture model, based on SP-mediated inflammation suitable to assess nanocarriers loaded with anti-inflammatory drugs.

Methods:

SP-mediated inflammation and the regulatory effect of free or encapsulated dexamethasone were determined by measuring interleukin-6 and interleukin-8 in culture medium of HaCaT (human adult low calcium temperature)-keratinocytes. Additionally, radical formation was analyzed by electron paramagnetic resonance spectroscopy. Cellular uptake of core-multishell nanocarriers was investigated by fluorescence microscopy. Cytotoxicity of all additives was determined by a viability assay.

Results:

SP-Stimulation of keratinocytes resulted in increased radical production and release of inflammatory cytokines without affecting cell viability. Induced inflammation was successfully downregulated by addition of free or encapsulated dexamethasone.

Conclusion:

SP-addition can be used as inflammatory stimulus in cell culture to mimic effects of aberrant enzymatic activities found in skin of atopic dermatitis patients. The set-up is appropriate as a preliminary test to examine the effectiveness of new molecules or delivery-systems to counteract serine protease-mediated inflammatory processes prior to skin studies.

Pinus densiflora bark extract ameliorates 2,4-dinitrochlorobenzene-induced atopic dermatitis in NC/Nga mice by regulating Th1/Th2 balance and skin barrier function

Korean red pine (Pinus densiflora) bark has been traditionally used in Korea and other parts of East Asia to relieve inflammatory diseases. Although many studies using P. densiflora bark have been reported, its effect on atopic dermatitis (AD) has not been elucidated. Thus, we investigated whether the P. densiflora bark extract (PBE) has potential to attenuate AD symptoms and elucidated the molecular mechanism. Oral administration of PBE to mice with 2,4-dinitrochlorobenzene (DNCB)-induced AD lessened dermatitis scores and scratching behavior and significantly reduced measures of epidermal thickness, infiltration of mast cells and eosinophils, levels of immunoglobulin E (IgE), and IgG₁ /IgG_2a ratio in serum. PBE not only inhibited IL-4, IL-5, and IL-13 but also increased IFN-γ in splenic production. Furthermore, PBE significantly suppressed mRNA expression of thymic stromal lymphopoietin and further downregulated the mRNA expression of Th2 and Th17 cytokines such as IL-4, IL-13, IL-17, IL-31, and TNF-α. In addition, the protein expressions of filaggrin, involucrin, and loricrin in lesional skin were recovered by PBE. These results suggest that PBE attenuates DNCB-induced AD via regulating Th1/Th2 balance and skin barrier function.

Microfluidic platforms for modeling biological barriers in the circulatory system

Microfluidic platforms have recently become popular as in vitro models because of their superiority in recapitulating microenvironments compared with conventional in vitro models. By providing various biochemical and biomechanical cues, healthy and diseased models at the organ level can be applied to disease progression and treatment studies. Microfluidic technologies are especially suitable for modeling biological barriers because the flow in the microchannels mimics the blood flow and body fluids at the interfaces of crucial organs, such as lung, intestine, liver, kidney, brain, and skin. These barriers have similar structures and can be studied with similar approaches for the testing of pharmaceutical compounds. Here, we review recent developments in microfluidic platforms for modeling biological barriers in the circulatory system.