Immunologic, microbial, and epithelial interactions in atopic dermatitis

Atopic dermatitis yardstick: Practical recommendations for an evolving therapeutic landscape

The implementation of treatment guidelines for atopic dermatitis is challenging, in part because of different guidance documents being used by different groups of specialists and in part because the language of guidelines often reflects the evidence base rather than the practical "how to." The Atopic Dermatitis Yardstick is part of a series developed in response to the need to proactively address the loss of disease control for atopic illnesses at all levels of severity. It presents a comprehensive update on how to conduct a sustained step-up in therapy for the patient with inadequately controlled or poorly controlled atopic dermatitis. Patient profiles, based on current guidelines and the authors' combined clinical experience, provide a practical and clinically meaningful guide to aid physicians in helping their patients achieve the goal of clear to almost clear. The intent is not to replace guidelines but to complement their recommendations incorporating the latest research and therapies.

Report from the National Institute of Allergy and Infectious Diseases workshop on "Atopic dermatitis and the atopic march: Mechanisms and interventions"

Atopic dermatitis (AD) affects up to 20% of children worldwide and is an increasing public health problem, particularly in developed countries. Although AD in infants and young children can resolve, there is a well-recognized increased risk of sequential progression from AD to other atopic diseases, including food allergy (FA), allergic rhinitis, allergic asthma, and allergic rhinoconjunctivitis, a process referred to as the atopic march. The mechanisms underlying the development of AD and subsequent progression to other atopic comorbidities, particularly FA, are incompletely understood and the subject of intense investigation. Other major research objectives are the development of effective strategies to prevent AD and FA, as well as therapeutic interventions to inhibit the atopic march. In 2017, the Division of Allergy, Immunology, and Transplantation of the National Institute of Allergy and Infectious Diseases sponsored a workshop to discuss current understanding and important advances in these research areas and to identify gaps in knowledge and future research directions. International and national experts in the field were joined by representatives from several National Institutes of Health institutes. Summaries of workshop presentations, key conclusions, and recommendations are presented herein.

Approach to the Assessment and Management of Adult Patients With Atopic Dermatitis: A Consensus Document. Section I: Pathophysiology of Atopic Dermatitis and Implications for Systemic Therapy

Atopic dermatitis (AD) is a chronic, relapsing, and remitting inflammatory skin disease whose onset typically occurs early in life. AD pathophysiology includes genetic, immune, and environmental factors contributing to chronic inflammation. A rapidly evolving understanding of the pathogenesis of AD has led to the development of several treatment options for AD in adults, including topicals, phototherapy, and systemic therapies. Here, we provide a concise summary of AD pathophysiology with a focus on implications for systemic therapy.

Estrogen reinforces barrier formation and protects against tumor necrosis factor alpha-induced barrier dysfunction in oral epithelial cells

Purpose

Epithelial barrier dysfunction is involved in the pathophysiology of periodontitis and oral lichen planus. Estrogens have been shown to enhance the physical barrier function of intestinal and esophageal epithelia, and we aimed to investigate the effect of estradiol (E2) on the regulation of physical barrier and tight junction (TJ) proteins in human oral epithelial cell monolayers.

Methods

HOK-16B cell monolayers cultured on transwells were treated with E2, an estrogen receptor (ER) antagonist (ICI 182,780), tumor necrosis factor alpha (TNFα), or dexamethasone (Dexa), and the transepithelial electrical resistance (TER) was then measured. Cell proliferation was measured by the cell counting kit (CCK)-8 assay. The levels of TJ proteins and nuclear translocation of nuclear factor (NF)-κB were examined by confocal microscopy.

Results

E2 treatment increased the TER and the levels of junctional adhesion molecule (JAM)-A and zonula occludens (ZO)-1 in a dose-dependent manner, without affecting cell proliferation during barrier formation. Treatment of the tight-junctioned cell monolayers with TNFα induced decreases in the TER and the levels of ZO-1 and nuclear translocation of NF-κB. These TNFα-induced changes were inhibited by E2, and this effect was completely reversed by co-treatment with ICI 182,780. Furthermore, E2 and Dexa presented an additive effect on the epithelial barrier function.

Conclusions

E2 reinforces the physical barrier of oral epithelial cells through the nuclear ER-dependent upregulation of TJ proteins. The protective effect of E2 on the TNFα-induced impairment of the epithelial barrier and its additive effect with Dexa suggest its potential use to treat oral inflammatory diseases involving epithelial barrier dysfunction.

Moisturizers versus Current and Next-Generation Barrier Repair Therapy for the Management of Atopic Dermatitis

We compare here the principal characteristics of over-the-counter moisturizers with physiologic lipid-based barrier repair therapy. Moisturizers are standard ancillary therapy for anti-inflammatory skin disorders, like atopic dermatitis (AD), and can attenuate the emergence of AD, the initial step in the "atopic march." But not all moisturizers are beneficial; some can make skin function worse, and can even induce inflammation, possibly accounting for the frequent occurrence of "sensitive skin" in women. In contrast, physiologic lipid-based barrier repair therapy, if comprised of the 3 key stratum corneum lipids, in sufficient quantities and at an appropriate molar ratio, can correct the barrier abnormality and reduce inflammation in AD, and perhaps in other inflammatory dermatoses.

Analysis of the Association of Polymorphisms rs5743708 in TLR2 and rs4986790 in TLR4 with Atopic Dermatitis Risk

BACKGROUND

We carried out a meta-analysis to assess whether Toll-like receptor 2 (TLR2) rs5743708 and Toll-like receptor 4 (TLR4) rs4986790 polymorphisms are associated with the risk of atopic dermatitis.

METHODS

A systematic search of PubMed, Embase, and Web of Science was performed to identify eligible case-control studies on the association of rs5743708 and rs4986790 with the risk of atopic dermatitis. Statistical analyses of the odds ratio (OR), 95% confidence interval (CI), and p value were performed using STATA software.

RESULTS

Our meta-analysis included a total of nine case-control studies, all involving Caucasian populations. With respect to the TLR2 rs5743708 G/A polymorphism, there was a statistically significant difference in the overall risk of atopic dermatitis between the case and control groups [OR = 2.07, p value of association test, p_{(association)} = 0.001 in allele (A vs. G) model; OR = 1.93, p_{(association)} = 0.004 in carrier (A vs. G) model; OR = 2.07, p_{(association)} = 0.001 in heterozygote (GA vs. GG) model; OR = 1.99, p_{(association)} = 0.001 in dominant (GA+ AA vs. GG) model]. Similar positive results were observed in the subgroup analysis of "population-based control." For the TLR4 rs4986790 A/G polymorphism, an increased atopic dermatitis risk was detected in the case group under the allele [OR = 1.78, p_{(association)} = 0.013], carrier [OR = 1.69, p_{(association)} = 0.027] and heterozygote [OR = 1.74, p_{(association)} = 0.020] models, but not the dominant [OR = 1.44, p_{(association)} = 0.070] model, in comparison to the population-based control group.

CONCLUSION

Our meta-analysis revealed a novel finding that the heterogeneous "GA" genotype of the TLR2 rs5743708 and "AG" genotype of the TLR4 rs4986790 may be associated with increased susceptibility to atopic dermatitis in Caucasians.

Testing biologics and intracellular signaling inhibitors on pediatric atopic dermatitis: a stairway to modern therapeutic approaches

INTRODUCTION

Atopic dermatitis (AD) is the most common cutaneous inflammatory disease in adults and children. In the last few years, the pathogenesis of AD has been profoundly revised, and this has led to the identification of novel druggable targets and the development of new agents targeting specific molecular pathways. Despite the high prevalence of AD in the pediatric population, the clinical development of new treatments, either topical or systemic, has been focused on the adult population in recent years; only a limited number of these new agents have been tested in pediatric cohorts.

AREAS COVERED

In this review, we describe the pathogenic model of pediatric AD which shows similarities and substantial differences when compared to adult AD. The identification of therapeutic targets is highlighted, and novel targeted therapies, both topical and systemic, are discussed.

EXPERT OPINION

The current therapeutic armamentarium for pediatric AD is very limited, and this represents a critical unmet need. The enhancement of clinical research on pediatric patients is necessary to facilitate an increase in the number of new targeted therapeutic options being available on the market.

Effect of short-term liver X receptor activation on epidermal barrier features in mild to moderate atopic dermatitis: A randomized controlled trial

BACKGROUND

Liver X receptors (LXRs) are involved in maintaining epidermal barrier and suppressing inflammatory responses in model systems. The LXR agonist VTP-38543 showed promising results in improving barrier function and inflammatory responses in model systems.

OBJECTIVE

To assess the safety, tolerability, cellular and molecular changes, and clinical efficacy of the topical VTP-38543 in adults with mild to moderate atopic dermatitis (AD).

METHODS

A total of 104 ambulatory patients with mild to moderate AD were enrolled in this randomized, double-blind, vehicle-controlled trial between December 2015 and September 2016. VTP-38543 cream in 3 concentrations (0.05%, 0.15%, and 1.0%) or placebo was applied twice daily for 28 days. Pretreatment and posttreatment skin biopsy specimens were obtained from a subset of 33 patients. Changes in SCORing of Atopic Dermatitis, Eczema Area and Severity Index, Investigator's Global Assessment, and tissue biomarkers (by real-time polymerase chain reaction and immunostaining) were evaluated.

RESULTS

Topical VTP-38543 was safe and well tolerated. VTP-38543 significantly increased messenger RNA (mRNA) expression of epidermal barrier differentiation (loricrin and filaggrin, P = .02) and lipid (adenosine triphosphate-binding cassette subfamily G member 1 and sterol regulatory element binding protein 1c, P < .01) measures and reduced epidermal hyperplasia markers (thickness, keratin 16 mRNA). VTP-38543 nonsignificantly suppressed cellular infiltrates and down-regulated mRNA expression of several T_H17/T_H22-related (phosphatidylinositol 3, S100 calcium-binding protein A12) and innate immunity (interleukin 6) markers.

CONCLUSION

Topical VTP-38543 is safe and well tolerated. Its application led to improvement in barrier differentiation and lipids. Longer-term studies are needed to clarify whether a barrier-based approach can induce meaningful suppression of immune abnormalities.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT02655679.