Pathophysiology of atopic dermatitis

The Skin Sebum and Moisture Levels of Children with Allergic Diseases: How Predictive Are They for House Dust Mite Allergy?

The aim was to evaluate the prediction of house dust mite allergy in children diagnosed with allergic disease based on their skin moisture and sebum levels. This is a case-control study including children with asthma, allergic rhinitis (AR), and atopic dermatitis (AD) and a healthy control group. The participants' skin moisture and sebum levels were measured non-invasively using a digital device. A total of 421 patients and 143 healthy children were included. The median value of skin moisture percentage was statistically significantly lower in asthma, AR, and AD patients compared to the control group (p < 0.001 for each). The median value of skin sebum percentage was significantly lower in asthma and AD patients compared to the control group (p = 0.002 and p = 0.003, respectively). ROC analysis was performed to assess the predictive value of skin moisture percentage for house dust mite allergy in respiratory allergic diseases (asthma and AR) and AD separately. Using a cut-off point of 35.5% for skin moisture in asthma and AR patients, the sensitivity and specificity were 81.3% and 56.5%, respectively. Although the specificity is low, the high sensitivity value is promising. The non-invasive measurement of skin sebum and moisture could provide convenience to clinicians in the diagnosis and management of allergic diseases.

Clinical trials of antibody drugs in the treatments of atopic dermatitis

Atopic dermatitis (AD) is one of the most common, relapsing, chronic inflammatory skin disease, being regarded as a global health issue. Recent studies have shown that Th2 cell-mediated type 2 immunity plays a central role in AD. The type 2 inflammatory cytokines such as IL-4, IL-13, IL-22, IL-31, IL-17 and IL-5 mediate the pathogenesis of AD. A variety of antibody drugs targeting these cytokines have been developed to treat AD in clinics. Notably, several antibody drugs have exhibited high efficacy in treating atopic dermatitis in previous studies, demonstrating that they could be therapeutic methods for AD patients. Herein, we reviewed the clinical trials of antibody drugs in the treatment of AD, which provides a useful guideline for clinicians to treat patients with AD in clinics.

Molecular Mechanisms of Luteolin Against Atopic Dermatitis Based on Network Pharmacology and in vivo Experimental Validation

PURPOSE

To undercover the underlying mechanisms of luteolin against atopic dermatitis (AD), clinically characterized by recurrent eczematous lesions and intense itching, based on network pharmacology, molecular docking and in vivo experimental validation.

METHODS

TCMSP, STITCH and SwissTargetPrediction databases were utilized to screen the corresponding targets of luteolin. Targets related to AD were collected from DisGeNET, GeneCards and TTD databases. PPI network of intersection targets was constructed through STRING 11.0 database and Cytoscape 3.9.0 software. GO and KEGG enrichment analysis were performed to investigate the critical pathways of luteolin against AD. Further, the therapeutic effects and candidate targets/signaling pathways predicted from network pharmacology analysis were experimentally validated in a mouse model of AD induced by 2, 4-dinitrofluorobenzene (DNFB).

RESULTS

A total of 31 intersection targets were obtained by matching 151 targets of luteolin with 553 targets of AD. Among all, 20 core targets were identified by PPI network topology analysis, including IL-6, TNF, IL-10, VEGFA, IL-4, etc., and molecular docking indicated that luteolin binds strongly to these core targets. KEGG pathway enrichment analysis suggested that the intersected targets were significantly enriched in IL-17 signaling pathway, Th17 cell differentiation, Th1 and Th2 cell differentiation, JAK/STAT signaling pathway, etc. The in vivo experiment validated that luteolin could alleviate AD-like skin symptoms, as evidenced by the lower SCORAD score, the reduced infiltration of mast cells and the recovery of skin barrier function. Furthermore, luteolin restored immune balance by regulating the production of Th1/Th2/Th17-mediated cytokines, which were both the predicted core targets. Moreover, luteolin inhibited the phosphorylation of JAK2 and STAT3 in the lesional skin.

CONCLUSION

Together, the present study systematically clarifies the ameliorative effects and possible molecular mechanisms of luteolin against AD through the combination of network pharmacology and experimental validation, shedding light on the future development and clinical application of luteolin.

Genetic Variants in Epidermal Differentiation Complex Genes as Predictive Biomarkers for Atopic Eczema, Allergic Sensitization, and Eczema-Associated Asthma in a 6-Year Follow-Up Case-Control Study in Children

Atopic eczema is the most common chronic inflammatory skin disease of early childhood and is often the first manifestation of atopic march. Therefore, one challenge is to identify the risk factors associated with atopic eczema that may also be predictors of atopic disease progression. The aim of this study was to investigate the association of SNPs in hornerin (HRNR) and filaggrin-2 (FLG2) genes with childhood atopic eczema, as well as other atopic phenotypes. Genotyping for HRNR and FLG2 was performed in 188 children younger than 2 years of age, previously screened for the FLG null mutations, and followed at yearly intervals until the age of 6. We demonstrated that risk variants of HRNR rs877776[C] and FLG2 rs12568784[T] were associated with atopic eczema, allergic sensitization, and susceptibility to the complex phenotype—asthma plus eczema. These effects seem to be supplementary to the well-known associations for FLG mutations and may be modulated by gene–gene interactions. Additionally, in children with eczema, these genetic variants may also be considered, along with FLG mutations, as predictive biomarkers for eczema-associated asthma. In conclusion, our results indicate that genetic variants in the epidermal differentiation complex gene could contribute to the pathogenesis of atopic eczema and progression to subsequent allergic disease.

Current and Emerging Strategies to Inhibit Type 2 Inflammation in Atopic Dermatitis

Type 2 immunity evolved to combat helminth infections by orchestrating a combined protective response of innate and adaptive immune cells and promotion of parasitic worm destruction or expulsion, wound repair, and barrier function. Aberrant type 2 immune responses are associated with allergic conditions characterized by chronic tissue inflammation, including atopic dermatitis (AD) and asthma. Signature cytokines of type 2 immunity include interleukin (IL)-4, IL-5, IL-9, IL-13, and IL-31, mainly secreted from immune cells, as well as IL-25, IL-33, and thymic stromal lymphopoietin, mainly secreted from tissue cells, particularly epithelial cells. IL-4 and IL-13 are key players mediating the prototypical type 2 response; IL-4 initiates and promotes differentiation and proliferation of naïve T-helper (Th) cells toward a Th2 cell phenotype, whereas IL-13 has a pleiotropic effect on type 2 inflammation, including, together with IL-4, decreased barrier function. Both cytokines are implicated in B-cell isotype class switching to generate immunoglobulin E, tissue fibrosis, and pruritus. IL-5, a key regulator of eosinophils, is responsible for eosinophil growth, differentiation, survival, and mobilization. In AD, IL-4, IL-13, and IL-31 are associated with sensory nerve sensitization and itch, leading to scratching that further exacerbates inflammation and barrier dysfunction. Various strategies have emerged to suppress type 2 inflammation, including biologics targeting cytokines or their receptors, and Janus kinase inhibitors that block intracellular cytokine signaling pathways. Here we review type 2 inflammation, its role in inflammatory diseases, and current and future therapies targeting type 2 pathways, with a focus on AD. INFOGRAPHIC.

Bee Venom Within Liposomes Synergistically Inhibit Atopic Dermatitis in Mice

Background: This study was performed to determine the effects of liposome-encapsulated bee venom (BV) treatment of inflammatory factors in atopic dermatitis (AD) compared with BV treatment.Methods: AD was induced by phthalic anhydride in mice and the effects of BV liposomes were measured. Using Leica Application Suite, thickened epidermis and dermis were measured after BV liposome treatment (0.05 and 0.1 μg/mL). The number of stained mast cells and the concentration of immunoglobulin (Ig)E were measured. Serum IgE concentration was analyzed using an enzyme-linked immunosorbent assay. The serum concentrations of interleukin (IL)-1, IL-4, and IL-6 inflammatory cytokines were measured. The levels of messenger ribonucleic acid expression of proinflammatory cytokines and chemokines were measured using reverse transcription polymerase chain reaction. Inhibition of mitogen-activated protein kinase activation, was analyzed on western blot. To measure the transcriptional activity (NF-κB inhibition by BV liposomes), western blots (p65, p-IκB, p50, and IκB) were also performed.Results: The weight of lymph nodes, serum IgE concentrations, morphological changes in the skins from the backs of the mice, and mast cell numbers in inflamed tissues were noticeably lower in the BV liposome treatment group compared with the BV treatment group. The concentrations of pro-inflammatory cytokines (IL-1, IL-4, IL-6) and chemokines (TSLP, CCL22) were also reduced. Activation of mitogen-activated protein kinase (p-ERK and p-p38), and transcriptional activity (p65, p-IκB, p50, and IκB) was strongly suppressed in the BV liposome group.Conclusion: BV liposomes may have a better therapeutic effect than BV for the treatment of AD.

Effect of Astaxanthin on Anti-Inflammatory and Anti-Oxidative Effects of Astaxanthin Treatment for Atopic Dermatitis-induced Mice

Background: This study sought to determine whether the antioxidant effects of astaxanthin (AST) could have an anti-inflammatory effect to reduce inflammation caused by atopic dermatitis (AD).Methods: Using a mouse model of AD induced by phtalic acid (PA), the levels of inflammation, inflammatory agents, and evidence of antioxidant activity were examined in PA treated mice (n = 3), PA-AST treated mice (n = 3), and a control group of mice (n = 3). This included measurements of ear thickness, levels of mast cells, IgE, inflammatory cytokine, malondialdehyde (MDA), hydrogen peroxide, HO-1, and GPx-1.Results: AST treatment significantly prevented inflammation as measured by ear thickness (<i>p</i> < 0.05), mast cell count (<i>p</i> < 0.001), and IgE concentration in the blood (<i>p</i> < 0.001). Levels of TNF-α (<i>p</i> < 0.001), IL-1β (<i>p</i> < 0.001), IL-6 (<i>p</i> < 0.001), and MDA (<i>p</i> < 0.05) were also significantly lower. In addition, GSH levels increased significantly (<i>p</i> < 0.001), and the level of hydrogen peroxide significantly reduced (<i>p</i> < 0.01). The expression of HO-1, GPx-1 increased.Conclusion: In this small experimental study, AST acted on inflammatory mechanisms that induced AD, through anti-inflammatory and antioxidant mechanisms, and is a candidate of interest in the clinical treatment of AD.

[Treatment of atopic dermatitis with dupilumab : A retrospective cohort analysis from dermatological practice]

Wir präsentieren die Ergebnisse einer retrospektiven Datenauswertung von 44 Patienten einer Praxiskohorte, deren atopische Dermatitis (AD) über bis zu 3 Jahre mit dem IL(Interleukin)-4/13-Rezeptor-Antikörper Dupilumab behandelt wurde. Die Betreuung erfolgte in den letzten 21 Monaten in einer Spezialsprechstunde Immundermatologie, in der die aufwendige Dokumentation realisiert werden konnte. Die Charakteristika der Kohorte hinsichtlich Alters- und Geschlechterverteilung, Schwere und Dauer der Erkrankung sind vergleichbar mit den großen Patientenkollektiven der Zulassungsstudien. Die therapeutische Effizienz unter Praxis-Alltagsbedingungen erwies sich als sehr gut (Anteil Patienten EASI [Eczema Area and Severity Index] 50, 75, 90 nach 16 Wochen: 94, 84, 60 %) und anhaltend (86 % EASI 90 nach 52 Wochen Therapie). Etwa die Hälfte unserer Patienten hatte anamnestisch oder bei Therapiebeginn eine Beteiligung der Gesichtshaut und/oder Augen. Diese Patientengruppe erwies sich als betreuungsintensiver, weil die Gesichts- und periorbitale Dermatitis sowie begleitende Konjunktividen verzögert abheilten, zu Rezidiven neigten und häufig einer zusätzlichen topischen Therapie bedurften. Wir haben keine schweren Nebenwirkungen in den hier ausgewerteten 48 Patientenjahren festgestellt. Dupilumab erwies sich als sichere und effiziente Therapie für die atopische Dermatitis in der dermatologischen Praxis.

New Treatments for Atopic Dermatitis Targeting Skin Barrier Repair via the Regulation of FLG Expression

Atopic dermatitis (AD) is one of the most common chronic, inflammatory skin disorders with a complex etiology and a broad spectrum of clinical phenotypes. Despite its high prevalence and effect on the quality of life, safe and effective systemic therapies approved for long-term management of AD are limited. A better understanding of the pathogenesis of atopic dermatitis in recent years has contributed to the development of new therapeutic approaches that target specific pathophysiological pathways. Skin barrier dysfunction and immunological abnormalities are critical in the pathogenesis of AD. Recently, the importance of the downregulation of epidermal differentiation complex (EDC) molecules caused by external and internal stimuli has been extensively emphasized. The purpose of this review is to discuss the innovations in the therapy of atopic dermatitis, including biologics, small molecule therapies, and other drugs by highlighting regulatory mechanisms of skin barrier-related molecules, such as filaggrin (FLG) as a crucial pathway implicated in AD pathogenesis.

[Treatment of simultaneously occurring urticaria and atopic dermatitis with dupilumab]

Our 21-year-old woman presented with symptoms of chronic spontaneous urticaria with angioedema and of cholinergic urticaria as well as of atopic dermatitis. Treatment with the IgE antibody omalizumab resulted in an improvement of urticaria; however, relapses of the atopic dermatitis occurred. The use of the monoclonal IL-4/13 receptor antibody dupilumab resulted in complete healing of the atopic dermatitis, complete remission of the chronic spontaneous urticaria with angioedema, and the satisfactory control of cholinergic flare ups over a follow-up period of 26 weeks.