Impact of a Decade of Research Into Atopic Dermatitis

Acupoint Autohemotherapy Attenuates DNCB-Induced Atopic Dermatitis and Activates Regulatory T Cells in BALB/c Mice

Purpose

Acupoint autohemotherapy (A-AHT) has been proposed as an alternative and complementary treatment for atopic dermatitis (AD), yet the exact role of its blood component in terms of therapeutic efficacy and mechanism of action is still largely unknown.

Methods

This study aimed to evaluate the therapeutic efficacies and action mechanisms of intramuscular injections of autologous whole blood (AWB) and mouse immunoglobulin G (IgG) (autologous or heterologous) at acupoints on 2,4-dinitrochlorobenzene (DNCB)-induced AD mouse models. Serum levels of total immunoglobulin E (IgE), IgG, interleukin-10 (IL-10), and interferon-gamma (IFN-γ) were measured, as well as mRNA expression levels of Forkhead box P3 (FoxP3), IL-10 and IFN-γ in dorsal skin lesions, and IL-10+, IFN-γ+ and FoxP3+CD4+T cells in murine spleen.

Results

It showed that repeated acupoint injection of AWB, autologous total IgG (purified from autologous blood in AD mice) or heterologous total IgG (purified from healthy blood in normal mice) effectively reduced the severity of AD symptoms and decreased epidermal and dermal thickness as well as mast cells in skin lesions. Additionally, AWB acupoint injection was found to upregulate FoxP3+, IL-10+ and IFN-γ+ CD4+T cells in murine spleen, suppressing the production of IgE antibodies and increasing that of IgG antibodies in the serum. Furthermore, both AWB and autologous total IgG administrations significantly elevated FoxP3 expression, mRNA levels of IL-10 and IFN-γ in dorsal skin lesions. However, acupoint injection of heterologous total IgG had no effect on regulatory T (Treg) and Th1 cells modulation.

Conclusion

These findings suggest that the therapeutic effects of A-AHT on AD are mediated by IgG-induced activation of Treg cells.

Genetic and Immunological Pathogenesis of Atopic Dermatitis

Type 2 immune-mediated diseases give a clear answer to the issue of nature (genetics) versus nurture (environment). Both genetics and environment play vital complementary roles in the development of atopic dermatitis (AD). As a key component of the atopic march, AD demonstrates the interactive nature of genetic and environmental contributions to atopy. From sequence variants in the epithelial barrier gene encoding FLG to the hygiene hypothesis, AD combines a broad array of contributions into a single syndrome. This review will focus on the genetic contribution to AD and where genetics facilitates the elicitation or enhancement of AD pathogenesis.

Epigenetic control of inflammation in Atopic Dermatitis

Atopic dermatitis (AD), also known as atopic eczema, is a common but also complex chronic, itchy skin condition with underlying inflammation of the skin. This skin ailment is prevalent worldwide and affects people of all ages, particularly children below five years of age. The itching and resulting rashes in AD patients are often the result of inflammatory signals, thus necessitating a closer look at the inflammation-regulating mechanisms for putative relief, care and therapy. Several chemical- as well as genetically-induced animal models have established the importance of targeting pro-inflammatory AD microenvironment. Epigenetic mechanisms are gaining attention towards a better understanding of the onset as well as the progression of inflammation. Several physiological processes with implications in pathophysiology of AD, such as, barrier dysfunction either due to reduced filaggrin / human β-defensins or altered microbiome, reprograming of Fc receptors with resulting overexpression of high affinity IgE receptors, elevated eosinophil numbers or the elevated IL-22 production by CD4 + T cells have underlying epigenetic mechanisms that include differential promoter methylation and/or regulation by non-coding RNAs. Reversing these epigenetic changes has been verified to reduce inflammatory burden through altered secretion of cytokines IL-6, IL-4, IL-13, IL-17, IL-22 etc, with benefit against AD progression in experimental models. A thorough understanding of epigenetic remodeling of inflammation in AD has the potential of opening avenues for novel diagnostic, prognostic and therapeutic options.

Development and Evaluation of Tacrolimus Loaded Nano-Transferosomes for Skin Targeting and Dermatitis Treatment

Tacrolimus (TRL) is used for the treatment of atopic dermatitis (AD) due to its T-cell stimulation effect. However, its significantly poor water solubility, low penetration and cytotoxicity have reduced its topical applications. Herein, tacrolimus loaded nano transfersomes (TRL-NTs) were prepared, followed by their incorporation into chitosan gel to prepare tacrolimus loaded nano transfersomal gel (TRL-NTsG). TEM analysis of the TRL-NTs was performed to check their morphology. DSC, XRD and FTIR analysis of the TRL-NTs were executed after lyophilization. Similarly, rheology, spreadability and deformability of the TRL-NTsG were investigated. In vitro release, ex vivo permeation and in vitro interaction of TRL-NTsG with keratinocytes and fibroblasts as well as their co-cultures were investigated along with their in vitro cell viability analysis. Moreover, in vivo skin deposition, ear thickness, histopathology and IgE level were also determined. Besides, 6 months stability study was also performed. Results demonstrated the uniformly distributed negatively charged nanovesicles with a mean particle size distribution of 163 nm and zeta potential of -27 mV. DSC and XRD exhibited the thermal stability and amorphous form of the drug, respectively. The TRL-NTsG showed excellent deformability, spreadability and rheological behavior. In vitro release studies exhibited an 8-fold better release of TRL from the TRL-NTsG. Similarly, 6-fold better permeation and stability of the TRL-NTsG with keratinocytes and fibroblasts as well as their co-cultures was observed. Furthermore, the ear thickness (0.6 mm) of the TRL-NTsG was found significantly reduced when compared with the untreated (1.7 mm) and TRL conventional gel treated mice (1.3 mm). The H&E staining showed no toxicity of the TRL-NTsG with significantly reduced IgE levels (120 ng/mL). The formulation was found stable for at least 6 months. These results suggested the efficacy of TRL in AD-induced animal models most importantly when incorporated in NTsG.

Histone deacetylase 3 inhibition alleviates 2,4-dinitrochlorobenzene-induced atopic dermatitis via epigenetically upregulating Nrf2/HO-1 signaling pathway

Atopic dermatitis (AD) is a frequent skin disorder that is associated with immune dysfunction and skin inflammation. Histone deacetylase 3 (HDAC3) possesses strong immune and inflammatory modulatory properties in multiple diseases. However, the role and mechanism of HDAC3 in AD remain unknown. Here, we reported that HDAC3 expression was aberrantly upregulated in 2,4-dinitrochlorobenzene (DNCB)-induced lesional AD skin in mice. Inhibition of HDAC3 by RGFP966 protected against DNCB-induced AD, indicated by improved histological damages, relieved inflammatory and immune dysfunction. Nuclear factor erythroid 2-related factor 2 (Nrf2)/heme oxygenase 1 (HO-1) signaling pathway activity in lesional AD skin was significantly decreased and RGFP966 attenuated the decrease. Inhibition of Nrf2/HO-1 signaling pathway via Nrf2 inhibitor ML385 blunted anti-AD effect of RGFP966 in DNCB-treated mice. Mechanistically, RGFP966 promoted Nrf2 expression and upregulated H3K27ac deposition on the promoter region of Nrf2. Collectively, HDAC3 inhibition protects against AD via epigenetically activating Nrf2 transcription to upregulate Nrf2/HO-1 signaling pathway activity. HDAC3 may act as a promising therapeutic target for the treatment of AD.

Atopic Dermatitis and the Risk of Infection in End-Stage Renal Disease

Background and Objectives: Atopic dermatitis (AD), also known as eczema, is a common chronic inflammatory skin condition affecting 16.5 million adults in the United States. AD is characterized by an impaired epidermal barrier that can predispose individuals to infection. End-stage renal disease (ESRD) is also commonly complicated by infections due to chronic vascular access and immune-system dysfunction, possibly related to uremia. Multiple studies have reported that renal disease is a common comorbidity in adults with atopic dermatitis. The aim of this study was to determine whether AD is a risk factor for certain infections in patients with ESRD. Materials and Methods: Using the United States Renal Data System, a retrospective cohort analysis was conducted on adult ESRD patients initiating dialysis between 2004 and 2019 to investigate associations between infections and AD in this population. Results: Of 1,526,266 patients, 2290 were identified with AD (0.2%). Infectious outcomes of interest were bacteremia, septicemia, cellulitis, herpes zoster, and conjunctivitis. In all infectious outcomes except for conjunctivitis, patients with the infectious outcomes were more likely to carry a diagnosis of AD. After controlling for demographic and clinical covariates, AD was associated with an increased risk of cellulitis (adjusted relative risk (aRR) = 1.39, 95% confidence interval (CI) = 1.31-1.47) and herpes zoster (aRR = 1.67, CI = 1.44-1.94), but not with bacteremia (aRR = 0.96, CI = 0.89-1.05), septicemia (aRR = 1.02, CI = 0.98-1.08), or conjunctivitis (aRR = 0.97, CI = 0.740-1.34). Conclusions: Overall, after controlling for demographic and clinical covariates and adjusting for person-years-at-risk, AD was associated with an increased risk for some, but not all, infections within the population of patients with ESRD.

A practical approach to caring for atopic dermatitis in children

PURPOSE OF REVIEW

Atopic dermatitis is a chronic, systemic disease with primary cutaneous clinical manifestations and is commonly attributed to an exaggerated Th2 inflammatory response. Recent research regarding risk factors, prevention, clinical features, and management of atopic dermatitis will be reviewed.

RECENT FINDINGS

In the last decade, advances have been made in identifying the factors that either confer increased risk for or protection from atopic dermatitis and associated atopy. Progress has also been made in the clinical management of this disease. Promising biomarkers and therapeutically informative characteristics of this disease have been identified in young children with and without the presence of eczema, but much has yet to be elucidated. Progress has also been made in clarifying the advantages and disadvantages of respective medical managements, including but not limited to topical corticosteroids, topical calcineurin inhibitors, phototherapy, systemic immunosuppressants, and targeted immunotherapy. Given that medical management may show variable efficacy in a child, an optimized skin care regimen is of utmost importance as well.

SUMMARY

Atopic dermatitis is a challenging, chronic systemic disease that incurs significant morbidity in affected children. Although management options have been somewhat disappointing in years past, promising results have been observed in recent advances in targeted immunotherapy.

Albumin-binding recombinant human IL-18BP ameliorates macrophage activation syndrome and atopic dermatitis via direct IL-18 inactivation

Given the clinical success of cytokine blockade in managing diverse inflammatory human conditions, this approach could be exploited for numerous refractory or uncontrolled inflammatory conditions by identifying novel targets for functional blockade. Interleukin (IL)-18, a pro-inflammatory cytokine, is relatively underestimated as a therapeutic target, despite accumulated evidence indicating the unique roles of IL-18 in acute and chronic inflammatory conditions, such as macrophage activation syndrome. Herein, we designed a new form of IL-18 blockade, i.e., APB-R3, a long-acting recombinant human IL-18BP linked to human albumin-binding Fab fragment, SL335, for extending half-life. We then explored the pharmacokinetics and pharmacodynamics of APB-R3. In addition to an extended serum half-life, APB-R3 alleviates liver inflammation and splenomegaly in a model of the macrophage activation syndrome induced in IL-18BP knockout mice. Moreover, APB-R3 substantially controlled skin inflammation in a model of atopic dermatitis. Thus, we report APB-R3 as a new potent IL-18 blocking agent that could be applied to treat IL-18-mediated inflammatory diseases.

The role of tralokinumab in the treatment of atopic dermatitis and future perspectives for adolescents

Atopic dermatitis (AD) is an inflammatory skin disease that frequently occurs in adolescents. Although there are many treatment options, the challenge for clinicians is finding an effective long-term drug for AD with a favorable safety profile. The purpose of this review is to describe the role of tralokinumab, an IL-13 inhibitor, in treating adolescent AD. The clinical efficacy and safety of tralokinumab were established in clinical trials for adults with moderate-to-severe AD. Based on the results of these trials and the preliminary results of trials conducted on adolescents with AD, tralokinumab effectively alleviates symptoms with tolerable adverse effects. Extending the use of tralokinumab to adolescents with moderate-to-severe AD seems promising for the future.

Atopic dermatitis and food allergy: To Test or not to test

One of the most challenging clinical scenarios in the field of allergy and immunology is the patient with uncontrolled atopic dermatitis (AD) and potential food allergy. These two diagnoses often coexist, but false-positive testing to foods is also prevalent. Physicians and other health care professionals may be concerned that not testing enough foods could lead to worsened AD severity or future systemic food reactions. However, testing too many foods can cause unnecessary food avoidance with varied subsequent consequences. Adding to this dilemma, patients and families with AD often request food allergy testing or present with test results in need of interpretation. The best path forward for these patients is nuanced, but evidenced-based medicine indicates that "less is more" when it comes to food allergy testing in patients with AD. This review explores when food testing is indicated based on the latest research and guidelines in food allergy and AD.

Single-Strain Probiotic Lactobacilli for the Treatment of Atopic Dermatitis in Children: A Systematic Review and Meta-Analysis

Probiotics are known for their positive effects on the gut microbiota. There is growing evidence that the infant gut and skin colonization have a role in the development of the immune system, which may be helpful in the prevention and treatment of atopic dermatitis. This systematic review focused on evaluating the effect of single-strain probiotic lactobacilli consumption on treating children's atopic dermatitis. Seventeen randomized placebo-controlled trials with the primary outcome of the Scoring Atopic Dermatitis (SCORAD) index were included in the systematic review. Clinical trials using single-strain lactobacilli were included. The search was conducted until October 2022 using PubMed, ScienceDirect, Web of Science, Cochrane library and manual searches. The Joanna Briggs Institute appraisal tool was used to assess the quality of the included studies. Meta-analyses and sub meta-analyses were performed using Cochrane Collaboration methodology. Due to different methods of reporting the SCORAD index, only 14 clinical trials with 1124 children were included in the meta-analysis (574 in the single-strain probiotic lactobacilli group and 550 in the placebo group) and showed that single-strain probiotic lactobacilli statistically significantly reduced the SCORAD index compared to the placebo in children with atopic dermatitis (mean difference [MD]: -4.50; 95% confidence interval [CI]: -7.50 to -1.49; Z = 2.93; p = 0.003; heterogeneity I² = 90%). The subgroup meta-analysis showed that strains of Limosilactobacillus fermentum were significantly more effective than strains of Lactiplantibacillus plantarum, Lacticaseibacillus paracasei or Lacticaseibacillus rhamnosus. A longer treatment time and younger treatment age statistically significantly reduced symptoms of atopic dermatitis. The result of this systematic review and meta-analysis shows that certain single-strain probiotic lactobacilli are more successful than others in reducing atopic dermatitis severity in children. Therefore, careful consideration to strain selection, treatment time and the age of the treated patients are important factors in enhancing the effectiveness of reducing atopic dermatitis in children when choosing probiotic single-strain lactobacilli.