New concept of the pathogenesis of atopic dermatitis: Interplay among the barrier, allergy, and pruritus as a trinity

Diterpenoid DGT alleviates atopic dermatitis-like responses in vitro and in vivo via targeting IL-4Rα

BACKGROUND

Atopic dermatitis is a common chronic inflammatory skin disease characterized by relapsing eczema and intense itch. DGT is a novel synthetic heterocyclic diterpenoid derived from plants. Its therapeutic potential and mechanism(s) of action are poorly understood.

OBJECTIVES

We investigated the potent therapeutic effect of DGT on atopic dermatitis, exploring the underlying mechanisms and determining whether DGT is a safe and well-tolerated topical treatment.

METHODS

We observed anti-inflammatory effects of DGT on tumor necrosis factor-α/interferon-γ-treated human keratinocytes, and anti-allergic effects on immunoglobulin E-sensitized bone marrow-derived mast cells. In vivo, DGT was topically applied to two experimental mouse models of atopic dermatitis: oxazolone-induced sensitization and topically applied calcipotriol. Then the therapeutic effects of DGT were evaluated physiologically and morphologically. Moreover, we performed nonclinical toxicology and safety pharmacology research, including general toxicity, pharmacokinetics, and safety pharmacology on the cardiovascular, respiratory, and central nervous systems.

RESULTS

In keratinocytes, DGT reduced the expression of inflammatory factors, promoting the expression of barrier functional proteins and tight junctions and maintaining the steady state of barrier function. DGT also inhibited the activation and degranulation of mast cells induced by immunoglobulin E. Moreover, we found that interleukin-4 receptor-α was the possible target of DGT. Meanwhile, DGT had therapeutic effects on oxazolone/calcipotriol-treated mice. Notably, our pharmacology results demonstrated that DGT was safe and nontoxic in our studies.

CONCLUSION

DGT's potent anti-inflammatory effects and good safety profile suggest that it is a potential candidate for the treatment of atopic dermatitis.

Integrating multi-omics approaches in deciphering atopic dermatitis pathogenesis and future therapeutic directions

Atopic dermatitis (AD), a complex and heterogeneous chronic inflammatory skin disorder, manifests in a spectrum of clinical subtypes. The application of genomics has elucidated the role of genetic variations in predisposing individuals to AD. Transcriptomics, analyzing gene expression alterations, sheds light on the molecular underpinnings of AD. Proteomics explores the involvement of proteins in AD pathophysiology, while epigenomics examines the impact of environmental factors on gene expression. Lipidomics, which investigates lipid profiles, enhances our understanding of skin barrier functionalities and their perturbations in AD. This review synthesizes insights from these omics approaches, highlighting their collective importance in unraveling the intricate pathogenesis of AD. The review culminates by projecting future trajectories in AD research, particularly the promise of multi-omics in forging personalized medicine and novel therapeutic interventions. Such an integrated multi-omics strategy is poised to transform AD comprehension and management, steering towards more precise and efficacious treatment modalities.

Roles of prostaglandins in immunosuppression

Prostaglandins (PGs) play a crucial and multifaceted role in various physiological processes such as intercellular signaling, inflammation regulation, neurotransmission, vasodilation, vasoconstriction, and reproductive functions. The diversity and biological significance of these effects are contingent upon the specific types or subtypes of PGs, with each PG playing a crucial role in distinct physiological and pathological processes. Particularly within the immune system, PGs are essential in modulating the function of immune cells and the magnitude and orientation of immune responses. Hence, a comprehensive comprehension of the functions PG signaling pathways in immunosuppressive regulation holds substantial clinical relevance for disease prevention and treatment strategies. The manuscript provides a review of recent developments in PG signaling in immunosuppressive regulation. Furthermore, the potential clinical applications of PGs in immunosuppression are also discussed. While research into the immunosuppressive effects of PGs required further exploration, targeted therapies against their immunosuppressive pathways might open new avenues for disease prevention and treatment.

Difamilast, a Topical Phosphodiesterase 4 Inhibitor, Produces Soluble ST2 via the AHR-NRF2 Axis in Human Keratinocytes

Difamilast, a phosphodiesterase 4 (PDE4) inhibitor, has been shown to be effective in the treatment of atopic dermatitis (AD), although the mechanism involved remains unclear. Since IL-33 plays an important role in the pathogenesis of AD, we investigated the effect of difamilast on IL-33 activity. Since an in vitro model of cultured normal human epidermal keratinocytes (NHEKs) has been utilized to evaluate the pharmacological potential of adjunctive treatment of AD, we treated NHEKs with difamilast and analyzed the expression of the suppression of tumorigenicity 2 protein (ST2), an IL-33 receptor with transmembrane (ST2L) and soluble (sST2) isoforms. Difamilast treatment increased mRNA and protein levels of sST2, a decoy receptor suppressing IL-33 signal transduction, without affecting ST2L expression. Furthermore, supernatants from difamilast-treated NHEKs inhibited IL-33-induced upregulation of TNF-α, IL-5, and IL-13 in KU812 cells, a basophil cell line sensitive to IL-33. We also found that difamilast activated the aryl hydrocarbon receptor (AHR)-nuclear factor erythroid 2-related factor 2 (NRF2) axis. Additionally, the knockdown of AHR or NRF2 abolished the difamilast-induced sST2 production. These results indicate that difamilast treatment produces sST2 via the AHR-NRF2 axis, contributing to improving AD symptoms by inhibiting IL-33 activity.

Exploring the Metabolic Effects of a Herbal Remedy of Asarum sieboldii, Platycodon grandiflorum, and Cinnamomum cassia Extracts: Unraveling Its Therapeutic Potential as a Topical Application for Atopic Dermatitis Treatment

Our previous study demonstrated that our novel herbal remedy, a mixture of Asarum sieboldii, Platycodon grandiflorum, and Cinnamomum Cassia extracts, exhibits a therapeutic effect in 1-chloro-2,4-dinitrobenzene (DNCB)-induced mice by inhibiting the Th-2 inflammatory response upon oral administration. It also ameliorated imbalances in lipid metabolism related to the skin barrier function in keratinocytes, indicating its potential as a topical agent. This study aims to further investigate the therapeutic effects and metabolic mechanisms of its topical application. The anti-atopic effect was evaluated using dermatitis scores, histopathological analysis, and immune cell factors in DNCB-induced mice. Metabolomic profiling of serum and lesional skin was conducted to elucidate the metabolic mechanisms. The topical application significantly reduced dermatitis scores, mast cell infiltration, and serum levels of immunoglobulin E (IgE), IFN-γ, interleukin (IL)-4, IL-17, and thymic stromal lymphopoietin (TSLP), demonstrating its effectiveness in treating atopic dermatitis (AD). Serum metabolomics revealed alterations in fatty acid metabolism related to the pro-inflammatory response. In lesional skin, metabolic markers associated with oxidative stress, immune regulation, and AD symptoms were restored. This study demonstrated its potential as a topical agent in suppressing Th-2 inflammatory responses and improving metabolic abnormalities related to AD symptoms, providing crucial insights for developing natural AD treatments.

Interplay of cytokines in the pathophysiology of atopic dermatitis: insights from Murin models and human

The pathogenesis of atopic dermatitis (AD) is understood to be crucially influenced by three main factors: dysregulation of the immune response, barrier dysfunction, and pruritus. In the lesional skin of AD, various innate immune cells, including Th2 cells, type 2 innate lymphoid cells (ILC2s), and basophils, produce Th2 cytokines [interleukin (IL)-4, IL-5, IL-13, IL-31]. Alarmins such as TSLP, IL-25, and IL-33 are also produced by epidermal keratinocytes, amplifying type 2 inflammation. In the chronic phase, not only Th2 cells but also Th22 and Th17 cells increase in number, leading to suppression of filaggrin expression by IL-4, IL-13, and IL-22, which further deteriorates the epidermal barrier function. Dupilumab, which targets IL-4 and IL-13, has shown efficacy in treating moderate to severe AD. Nemolizumab, targeting IL-31RA, effectively reduces pruritus in AD patients. In addition, clinical trials with fezakinumab, targeting IL-22, have demonstrated promising results, particularly in severe AD cases. Conversely, in murine models of AD, several cytokines, initially regarded as promising therapeutic targets, have not demonstrated sufficient efficacy in clinical trials. IL-33 has been identified as a potent activator of immune cells, exacerbating AD in murine models and correlating with disease severity in human patients. However, treatments targeting IL-33 have not shown sufficient efficacy in clinical trials. Similarly, thymic stromal lymphopoietin (TSLP), integral to type 2 immune responses, induces dermatitis in animal models and is elevated in human AD, yet clinical treatments like tezepelumab exhibit limited efficacy. Therapies targeting IL-1α, IL-5, and IL-17 also failed to achieve sufficient efficacy in clinical trials. It has become clear that for treating AD, IL-4, IL-13, and IL-31 are relevant therapeutic targets during the acute phase, while IL-22 emerges as a target in more severe cases. This delineation underscores the necessity of considering distinct pathophysiological aspects and therapeutic targets in AD between mouse models and humans. Consequently, this review delineates the distinct roles of cytokines in the pathogenesis of AD, juxtaposing their significance in human AD from clinical trials against insights gleaned from AD mouse models. This approach will improve our understanding of interspecies variation and facilitate a deeper insight into the pathogenesis of AD in humans.

Evodiae Fructus extract suppresses inflammatory response in HaCaT cells and improves house dust mite-induced atopic dermatitis in NC/Nga mice

This study was conducted to assess the effect of Evodiae Fructus 70% ethanol extract (EFE) on the pathology of atopic dermatitis using in vitro and in vivo models. The major compounds in EFE were identified by ultra-performance liquid chromatography with tandem mass spectrometry as rutaecarpine, evodiamine, evodol, dehydroevodiamine, limonin, synephrine, evocarpine, dihydroevocarpine, and hydroxyevodiamine. EFE significantly decreased chemokine levels in tumor necrosis factor-α/interferon-γ-stimulated HaCaT cells. In house dust mite-treated NC/Nga mice, topical application of EFE significantly decreased the dermatitis score, epidermal hyperplasia and thickening, mast cell infiltration, and plasma levels of histamine and corticosterone. Thymic stromal lymphopoietin, CD4+ T cells, interleukin-4, and intercellular adhesion molecule-1 expression in the lesioned skin was reduced in the treated mice. The mechanism of EFE was elucidated using transcriptome analysis, followed by experimental validation using Western blotting in HaCaT cells. EFE down-regulated the activation of Janus kinase (JAK)-signal transducers and activators of transcription (STAT) and mitogen-activated protein kinases (MAPK) signaling pathways in HaCaT cells. EFE improves atopic dermatitis-like symptoms by suppressing inflammatory mediators, cytokines, and chemokines by regulating the JAK-STAT and MAPK signaling pathways, suggesting its use as a potential agent for the treatment of atopic dermatitis.

Skin delivery of synthetic benzoyl pterostilbenes suppresses atopic dermatitis-like inflammation through the inhibition of keratinocyte and macrophage activation

Atopic dermatitis (AD) is one of the most common skin autoimmune diseases needing continuous anti-inflammatory management. Pterostilbene is reported to exhibit anti-inflammatory activity with higher bioavailability and stability than its parent compound, resveratrol. In this study, a series of synthetic pterostilbene analogs were designed by the hybridization of pterostilbene with chalcones or benzoyl chloride. Seventeen analogs derived from pterostilbene were synthesized with differences in the positions of hydroxyl, methoxyl, or fluoro moieties. These compounds were screened by the inhibitory effect on the overexpressed Th2-associated cytokines/chemokines in the activated human keratinocytes (HaCaT). The anti-IL-5 and anti-CCL5 activity of these compounds led to the identification of three effective compounds: 3a ((E)- 4-(3,5-dimethoxystyryl)phenyl benzoate), 3d ((E)- 4-(3,5-dimethoxystyryl)phenyl 2-methoxybenzoate), and 3g ((E)- 4-(3,5-dimethoxystyryl)phenyl 2-fluorobenzoate). These benzoyl pterostilbenes also significantly decreased Th1/Th17-associated proinflammatory mediators in the activated macrophages (differentiated THP-1). The result showed that the conditioned medium of benzoyl pterostilbene-treated macrophages reduced the phosphorylated STAT3 in the keratinocytes, indicating the blockade of crosstalk between resident and immune cells. Compounds 3d and 3g generally showed greater skin absorption than 3a. The flux of 3g across barrier-defective skins mimicking the AD skin was 3-fold higher than that of across intact skin. The dinitrochlorobenzene (DNCB)-induced AD mouse model manifested that topical delivery with 3g improved the pathological signs through inhibiting cytokines/chemokines (IL-5, TNF-α, CCL17, and CCL22) and macrophage recruitment. The epidermal thickness was reduced from 76 to 55 µm after topical 3g delivery. The therapeutic activity of 3g was comparable to that of tacrolimus (TAC) used as a positive control. The benzoyl pterostilbenes attenuated the inflammation via the MAPK and c-Jun signaling. Furthermore, this study provided experimental evidence of benzoyl pterostilbene analogs for therapeutic potential on AD.

Intrapatient comparison of atopic dermatitis skin transcriptome shows differences between tape-strips and biopsies

BACKGROUND

Our knowledge of etiopathogenesis of atopic dermatitis (AD) is largely derived from skin biopsies, which are associated with pain, scarring and infection. In contrast, tape-stripping is a minimally invasive, nonscarring technique to collect skin samples.

METHODS

To construct a global AD skin transcriptomic profile comparing tape-strips to whole-skin biopsies, we performed RNA-seq on tape-strips and biopsies taken from the lesional skin of 20 moderate-to-severe AD patients and the skin of 20 controls. Differentially expressed genes (DEGs) were defined by fold-change (FCH) ≥2.0 and false discovery rate <0.05.

RESULTS

We detected 4104 (2513 Up; 1591 Down) and 1273 (546 Up; 727 Down) DEGs in AD versus controls, in tape-strips and biopsies, respectively. Although both techniques captured dysregulation of key immune genes, tape-strips showed higher FCHs for innate immunity (IL-1B, IL-8), dendritic cell (ITGAX/CD11C, FCER1A), Th2 (IL-13, CCL17, TNFRSF4/OX40), and Th17 (CCL20, CXCL1) products, while biopsies showed higher upregulation of Th22 associated genes (IL-22, S100As) and dermal cytokines (IFN-γ, CCL26). Itch-related genes (IL-31, TRPV3) were preferentially captured by tape-strips. Epidermal barrier abnormalities were detected in both techniques, with terminal differentiation defects (FLG2, PSORS1C2) better represented by tape-strips and epidermal hyperplasia changes (KRT16, MKI67) better detected by biopsies.

CONCLUSIONS

Tape-strips and biopsies capture overlapping but distinct features of the AD molecular signature, suggesting their respective utility for monitoring specific AD-related immune, itch, and barrier abnormalities in clinical trials and longitudinal studies.

The role of Janus kinase signaling in the pathology of atopic dermatitis

Atopic dermatitis (AD) is a heterogeneous, chronic, relapsing, inflammatory skin disease associated with considerable physical, psychological, and economic burden. The pathology of AD includes complex interactions involving abnormalities in immune and skin barrier genes, skin barrier disruption, immune dysregulation, microbiome disturbance, and other environmental factors. Many of the cytokines involved in AD pathology, including IL-4, IL-13, IL-22, IL-31, thymic stromal lymphopoietin, and IFN-γ, signal through the Janus kinase (JAK)-signal transducer and activation of transcription (STAT) pathway. The JAK family includes JAK1, JAK2, JAK3, and tyrosine kinase 2; the STAT family includes STAT1, STAT2, STAT3, STAT4, STAT5A/B, and STAT6. Activation of the JAK-STAT pathway has been implicated in the pathology of several immune-mediated inflammatory diseases, including AD. However, the exact mechanisms of JAK-STAT involvement in AD have not been fully characterized. This review aims to discuss current knowledge about the role of the JAK-STAT signaling pathway and, specifically, the role of JAK1 in the pathology and symptomology of AD.

Bleach baths enhance skin barrier, reduce itch but do not normalize skin dysbiosis in atopic dermatitis

Studies have demonstrated that bleach baths improve atopic dermatitis (AD) severity; however, the effects on itch, skin barrier, and cutaneous microbial composition are less clear. We examined whether bleach baths reduce itch, normalize skin barrier function, reduce S. aureus absolute abundance, and increase microbial diversity in adults with AD who were colonized with S. aureus on their non-lesional skin. This was an open label, non-randomized, controlled trial performed at a single academic center. Fifteen AD and five non-atopic healthy controls (NA) were instructed to take two bleach baths (0.005% NaClO; 5-10 min duration) per week for a total of 12 weeks as add-on therapy. Adults 18 to 65 years (inclusive) with mild to severe AD were recruited with EASI score > 6.0, S. aureus culture positivity, access to a bathtub, and ability and willingness to maintain current topical or systemic treatments. They were evaluated at baseline (before bleach baths), 6 weeks, and 12 weeks after the intervention of twice-weekly bleach baths. Efficacy measurements included EASI as well as 5-D Pruritus and ItchyQoL™. Transepidermal water loss (TEWL) and stratum corneum (SC) integrity assay were performed to assess the skin barrier. Skin dysbiosis was measured by S. aureus cultivation, S. aureus abundance (qPCR of thermonuclease gene), and V1-V3 16S rRNA gene sequencing on non-lesional and lesional AD skin. After 12 weeks of bleach baths, 8/15 (53.3%) AD subjects achieved an EASI50 and a significant reduction in itch as measured by 5-D pruritus and Itchy QoL. Eighty-seven percent reported improvements in sleep quality. At study entry, AD subjects had higher non-lesional TEWL values than NA subjects, and only AD subjects experienced a reduction with bleach baths (p = 0.006). Similarly, SC integrity improved as early as 6 weeks after bleach baths in AD subjects. Notably, bleach baths had no significant effect on S. aureus culture-positivity, qPCR absolute abundance, or microbial diversity. The addition of twice-weekly bleach baths improves investigator-assessed AD severity, patient-reported pruritus and sleep as well as physiological measures of skin barrier function in adult AD subjects while having no effect on qualitative and quantitative measures of cutaneous S. aureus. Trial Registration: ClinicalTrials.gov Identifier: NCT01996150, Date of registration: November 27th, 2013.

The pivotal role of Bifida Ferment Lysate on reinforcing the skin barrier function and maintaining homeostasis of skin defenses in vitro

BACKGROUND

The semiactive or inactive probiotics or their extracts used in dermatology have interesting properties to ameliorate signs of irritated skin and enhance the skin barrier. Bifidobacterium, as the most common probiotics, which has been found to be effective in reducing acne and improving the skin barrier function of atopic dermatitis. Bifida Ferment Lysate (BFL) can be obtained from Bifidobacterium by fermentation and extraction.

PURPOSE

In this study, we investigated the effect of a topically used BFL on the skin using in vitro evaluation methods.

RESULTS

The results showed that upregulation of skin physical barrier gene (FLG, LOR, IVL, TGM1, and AQP3) and antimicrobial peptide gene (CAMP and hBD-2) in HaCaT cells by BFL might be responsible for skin barrier resistance. In addition, BFL had strong antioxidant properties representing a dose-dependent increasing of the scavenging capacity of DPPH, ABTS, hydroxyl, and superoxide radicals. BFL treatment also fundamentally inhibited the intracellular ROS and MDA production and improved the activities of antioxidant enzymes (CAT and GSH-Px) in H2 O2 -stimulated HaCaT cells. As a good immunomodulatory factor, BFL efficiently decreased the secretion of IL-8 and TNF-α cytokines, and COX-2 mRNA expression in LPS-induced THP-1 macrophages.

CONCLUSION

BFL can strengthen the skin barrier function and stimulate skin barrier resistance, to reinforce the skin against oxidative stress and inflammatory stimuli.

Macrophage autophagy deficiency-induced CEBPB accumulation alleviates atopic dermatitis via impairing M2 polarization

Macroautophagy/autophagy plays a pivotal role in immune regulation. Its significance is evident in modulation of immune cell differentiation and maturation, physiologically and pathologically. Here, we investigate the role of macrophage autophagy on the development of atopic dermatitis (AD). By employing an MC903-induced AD mice model, we observe reduced cutaneous inflammation in macrophage Atg5 cKO mice compared with WT mice. Notably, there is a decreased infiltration of M2 macrophages in lesional skin from Atg5 cKO mice. Furthermore, impaired STAT6 phosphorylation and diminished expression of M2 markers are detected in autophagy-deficient macrophages. Our mechanistic exploration reveals that CEBPB drives the transcription of SOCS1/3 and SQSTM1/p62-mediated autophagy degrades CEBPB normally. Autophagy deficiency leads to CEBPB accumulation, and further promotes the expression of SOCS1/3. This process inhibits JAK1-STAT6 pathway activation and M2 marker expression. Together, our study indicates that autophagy is required for M2 activation and macrophage autophagy may be a promising target for AD intervention.

Emerging nanotechnology backed formulations for the management of atopic dermatitis

Atopic dermatitis is a prevalent chronic skin inflammation affecting 2.1 to 4.1% of adults globally. The complexity of its pathogenesis and the relapsing nature make it challenging to treat. Current treatments follow European Academy of Dermatology and Venerology guidelines, but advanced cases with recurring lesions lack effective therapies. To address this gap, researchers are exploring nanotechnology for targeted drug delivery. Nanoparticles offer benefits such as improved drug retention, stability, controlled release and targeted delivery through the disrupted epidermal barrier. This integrated review evaluates the current state of AD treatment and highlights the potential of novel nano-formulations as a promising approach to address the disease.

3D biofabrication of diseased human skin models in vitro

Human skin is an organ located in the outermost part of the body; thus, it frequently exhibits visible signs of physiological health. Ethical concerns and genetic differences in conventional animal studies have increased the need for alternative in vitro platforms that mimic the structural and functional hallmarks of natural skin. Despite significant advances in in vitro skin modeling over the past few decades, different reproducible biofabrication strategies are required to reproduce the pathological features of diseased human skin compared to those used for healthy-skin models. To explain human skin modeling with pathological hallmarks, we first summarize the structural and functional characteristics of healthy human skin. We then provide an extensive overview of how to recreate diseased human skin models in vitro, including models for wounded, diabetic, skin-cancer, atopic, and other pathological skin types. We conclude with an outlook on diseased-skin modeling and its technical perspective for the further development of skin engineering.

The Impact of Air Pollution on Atopic Dermatitis

PURPOSE OF REVIEW

Atopic dermatitis (AD) remains a dermatological disease that imposes a significant burden on society. Air pollution has previously been linked to both the onset and severity of atopic dermatitis. As air pollution remains a critical environmental factor impacting human health, this review seeks to provide an overview of the relationship between different air pollutants and AD.

RECENT FINDINGS

AD can develop from multiple causes that can be broadly grouped into epidermal barrier dysfunction and immune dysregulation. Air pollution imposes significant health risks and includes a wide variety of pollutant types. AD has been linked to outdoor air pollutants such as particulate matter (PM), volatile organic compounds (VOC), gaseous compounds, and heavy metals. Exposure to indoor pollutants such as tobacco smoke and fungal molds has also been associated with an increased incidence of AD. While different pollutants impact distinct molecular pathways in the cell, they mostly converge on ROS product, DNA damage, and dysregulated T-cell activity and cytokine production. The presented review suggests a strengthening tie between air pollution and AD. It points to opportunities for further studies to clarify, as well as potential therapeutic opportunities that leverage the mechanistic relationships between air pollution and AD.

Antigen-specific T cell balance reveals Why patients with atopic dermatitis fail to achieve immune tolerance

The number of regulatory T cells (Tregs) and how they behave in the pathogenesis of atopic dermatitis (AD) are still controversial. We identified and quantified Tregs, mite-specific Tregs, and mite-specific effector T cells (Teffs) in patients with AD and healthy controls (HCs). We collected peripheral blood and analyzed the cells using flow cytometry after stimulation with mite antigens. Mite-specific Tregs and mite-specific Teffs were recognized by the expression of CD137 and CD154, respectively. Patients with AD had more Tregs than HCs; however, when focusing on a single antigen, the ratio of mite-specific Tregs/Teffs was lower in patients with AD than in HCs. Furthermore, the mite-specific Teffs in patients with AD were more likely to produce proinflammatory cytokines interleukin (IL)-4 and IL-13. This Teff-dominant imbalance is thought to be the cause of development of atopic status in patients with AD without immune tolerance.

Anti-Atopic Activities of Sargassum horneri Hot Water Extracts in 2,4-Dinitrochlorobezene-Induced Mouse Models

Atopic dermatitis (AD) is a chronic inflammation associated with skin hypersensitivity caused by environmental factors. The objent of this study was to assess the hot water extracts of Sargassum horneri (SHHWE) on AD. AD was induced by spreading 2,4-dinitrochlorobenzene (DNCB) on the BALB/c mice. The efficacy of SHHWE was tested by observing the immunoglobulin E (IgE), cytokine, skin clinical severity score and cytokine secretions in concanavalin A (Con A)-stimulated splenocytes. The levels of interleukine (IL)-4, IL-5 and IgE, the pro-inflammatory cytokines that are closely related, were notably suppressed in a does-dependent manner by SHHWE, whereas the level of interferon γ (IFN-γ), the atopy-related Th1 cytokine inhibiting the production of Th2 cytokines, was increased. Therefore, these results show that SHHWE has a potent anti-inhibitory effect on AD and is highly valuable for cosmetic development.

Increased production of natural moisturizing factors and bleomycin hydrolase activity in elderly human skin

BACKGROUND

Bleomycin hydrolase (BH), which is expressed in the stratum granulosum and lower stratum corneum (SC), is involved in final filaggrin degradation. Furthermore, BH plays an essential role in producing free amino acids, which constitute the majority of natural moisturizing factors (NMF). However, the effects of BH expression and protease activity on human skin aging remain unclear.

OBJECTIVE

This study was designed to evaluate the activity and expression patterns of BH in SC extracts from healthy young and elderly individuals.

METHODS

SC samples were collected by tape stripping. BH activity was assessed by measuring the citrulline aminopeptidase activity. BH expression was determined by Western blotting, and NMF was quantified by liquid chromatography/mass spectrometry. Skin barrier function was determined by measuring SC hydration, transepidermal water loss (TEWL), and skin pH.

RESULTS

The activity and expression of BH were higher in the elderly skin than in young skin, and BH activity was correlated with BH expression levels. Evaluation of the NMF showed that the levels of total amino acids, such as glycine, serine, aspartic acid, citrulline, pyrrolidone carboxylic acid (a metabolite of glutamic acid), and trans-urocanic acid (a metabolite of histidine), were significantly higher in elderly skin than in young skin. Moreover, SC hydration and TEWL were significantly lower in elderly, indicating dry skin, and pH was significantly higher in elderly, indicating greater skin alkalinization.

CONCLUSION

These results suggest that BH activity and expression, as well as NMF amino acids, increase in elderly people as compensatory mechanisms against dry skin.

Hochuekkito exerts the anti-allergic effects via activating regulatory T cells in a murine model of contact hypersensitivity

Hochuekkito (HET) is a Kampo prescription, used for the clinical treatment of skin diseases such as atopic dermatitis (AD), in Japan. Oral administration of HET exerts anti-allergic effects in an experimental dermatitis mice model and in patients with atopic dermatitis; however, the mechanism underlying the anti-allergic effects of HET is still unclear. Therefore, we investigated the immunopharmacological properties of the anti-allergic actions of HET using a 2,4,6-trinitrochlorobenzene (TNCB)-induced murine contact hypersensitivity (CHS) model and adoptive cell transfer experiments. Oral administration of HET (1.4 g/kg) exhibited anti-allergic effects in a TNCB-induced CHS model via activation of Tregs; this activation was observed even without antigen sensitization in donor mice. Activation was dependent on the duration of HET administration and required at least 4 days of dosing. In addition, the anti-allergic effects of HET through the activation of Tregs were not antigen specific. Flow cytometry results indicated that the proportion of CD4+CD25+Foxp3+ cells in the splenic lymphocytes increased after oral administration of HET. Therefore, oral administration of HET induced both inducible regulatory T cells (iTregs) and thymus-derived naturally occurring regulatory T cells (nTregs). Ginseng radix and Bupleuri radix were involved in the anti-allergic actions of HET through the induction and/or activation of Tregs; Bupleuri radix participated in the activation of nTregs. In conclusion, our findings suggest that HET exerts the anti-allergic effects through the induction and/or activation of Tregs. These findings elucidate the usefulness of HET as an immunomodulator.

Myricetin treatment has ameliorative effects in DNFB-induced atopic dermatitis mice under high-fat conditions

Atopic dermatitis (AD) is a chronic, inflammatory cutaneous disorder. Obesity is associated with increased prevalence and severity of AD for reasons that remain poorly understood. Myricetin, a dietary flavonoid found in fruits and vegetables, is known to have anti-inflammatory effects, but its role in AD is unclear. Thus, we investigated the effects of obesity on exacerbation AD lesions and evaluated the effects of myricetin on obese AD. Mice were fed normal diet (ND) or high-fat diet, and then 2,4-dinitrofluorobenzene was used to induce AD-like lesions. We found that obesity exacerbated AD lesions, and myricetin topical administration ameliorated symptoms and skin lesions of obsess AD mice, such as dermatitis scores, scratching behavior, epidermal thickness, and mast cell infiltration. In addition, myricetin reduced the levels of immunoglobulin E and histamine, inhibited the infiltration of CD4+T cells, and modulated the expression of Th1, Th2, Th17, and Th22 cytokines and pro-inflammatory factors (CCL17, CCL22, IL-1β, and TGF-β). Moreover, myricetin restored impaired barrier function by reducing transepidermal water loss, increasing lamellar body secretion, as well as upregulating the mRNA and protein expression of filaggrin. Western blot results showed that significantly increased levels of phosphorylated IκB and NF-κB p65 was observed in the obese AD mice compared with the AD mice fed ND, whereas the myricetin could downregulated the phosphorylations of IκB and NF-κB, and inhibited mRNA expression of iNOS and COX2. Taken together, our results suggest that myricetin treatment exhibits potentially protective effects against the obeseassociated AD by inhibiting inflammatory response and restoring skin barrier function.

Air Pollution and Atopic Dermatitis, from Molecular Mechanisms to Population-Level Evidence: A Review

Atopic dermatitis (AD) has increased in prevalence to become the most common inflammatory skin condition globally, and geographic variation and migration studies suggest an important role for environmental triggers. Air pollution, especially due to industrialization and wildfires, may contribute to the development and exacerbation of AD. We provide a comprehensive, multidisciplinary review of existing molecular and epidemiologic studies on the associations of air pollutants and AD symptoms, prevalence, incidence, severity, and clinic visits. Cell and animal studies demonstrated that air pollutants contribute to AD symptoms and disease by activating the aryl hydrocarbon receptor pathway, promoting oxidative stress, initiating a proinflammatory response, and disrupting the skin barrier function. Epidemiologic studies overall report that air pollution is associated with AD among both children and adults, though the results are not consistent among cross-sectional studies. Studies on healthcare use for AD found positive correlations between medical visits for AD and air pollutants. As the air quality worsens in many areas globally, it is important to recognize how this can increase the risk for AD, to be aware of the increased demand for AD-related medical care, and to understand how to counsel patients regarding their skin health. Further research is needed to develop treatments that prevent or mitigate air pollution-related AD symptoms.

Langerhans Cells-Revising Their Role in Skin Pathologies

Langerhans cells (LCs) constitute a cellular immune network across the epidermis. Because they are located at the skin barrier, they are considered immune sentinels of the skin. These antigen-presenting cells are capable of migrating to skin draining lymph nodes to prime adaptive immune cells, namely T- and B-lymphocytes, which will ultimately lead to a broad range of immune responses. Moreover, LCs have been shown to possess important roles in the anti-cancer immune responses. Indeed, the literature nicely highlights the role of LCs in melanoma. In line with this, LCs have been found in melanoma tissues where they contribute to the local immune response. Moreover, the immunogenic properties of LCs render them attractive targets for designing vaccines to treat melanoma and autoimmune diseases. Overall, future studies will help to enlarge the portfolio of immune properties of LCs, and aid the prognosis and development of novel therapeutic approaches to treating skin pathologies, including cancers.

An evaluation of abrocitinib for moderate-to-severe atopic dermatitis

INTRODUCTION

Atopic dermatitis (AD) is a common itchy inflammatory skin condition that affects many individuals. For many years, the landscape of AD treatment remained unchanged; however, there has been developing therapies that directly target the underlying immunological mechanism of AD. Janus kinase (JAK) inhibitors are small molecules that have shown anti-inflammatory and anti-itch effects in AD. Recently, abrocitinib, an oral JAK 1 inhibitor, was approved by the Food and Drug Administration for atopic dermatitis.

AREAS COVERED

By downregulating the immune cascade, abrocitinib has demonstrated the ability to curb symptoms of AD, including rapidly reducing pruritus in 2-3 days, and is safe and well-tolerated overall despite a low increased risk in infection. The data discussed was obtained from a comprehensive literature review utilizing PubMed.

EXPERT OPINION

Abrocitinib has strong efficacy, likely due to its broader mechanism of action provided by the inhibition of key regulatory molecule, JAK. Results have demonstrated that it is more efficacious at curbing symptoms of AD than dupilumab, the current treatment of choice for refractory, moderate-to-severe AD. While abrocitinib provides a great alternative treatment, particularly for non-responders and AD subtypes, it also demonstrates a stronger side effect profile that must be considered.

Real-World Evidence of an Emollient Device for Atopic and Contact Dermatitis in Pediatric to Adult Patients - Data from a Post-Marketing Surveillance

Purpose

Atopic and contact dermatitis have been attributed to skin barrier abnormalities, immune system dysfunction and inflammation leading to pruritus. As these factors may involve oxidative stress, emollient devices containing antioxidants furfuryl palmitate and tocopherol may help reduce itching and inflammation. In this study, a post-marketing questionnaire was carried out of 40 users of a novel emollient device containing furfuryl palmitate and tocopherol (Relizema™ cream), who purchased it from a pharmacy or health-care professional to ascertain the emollient device's action on itching, flushing and moisturizing.

Patients and Methods

The post-marketing questionnaire, administered by trained pharmacy and health-care staff, collected data on age; diagnosis; number of times per day and for how many days the emollient device was applied; whether the product helped alleviate itching and flushing, and in what time frame if so; and how their skin felt after using the emollient.

Results

Most patients had atopic dermatitis (n = 25) or irritant contact dermatitis (n = 10); most were aged ≥19 years (n = 20) or between 3 and 12 years (n = 12). Most used the emollient device twice a day (n = 26) or more (n = 11) with 27 using it for ≤30 days. Patients predominantly reported that the emollient device "significantly improved" itching (n = 34) and flushing (n = 31) with a response being noted within 1 day (n = 17) or 1 week (n = 22). All users felt the product "protected and moisturized" their skin, the product texture was "pleasant" to "excellent" and the "non-fragrance" smell was "acceptable" to "excellent".

Conclusion

Use of a novel emollient device containing ingredients aimed at managing atopic or contact dermatitis, including furfuryl palmitate and tocopherol, led to rapid improvements in itching and flushing. The emollient device was acceptable to the users.

Impact of itch and skin pain on quality of life in adult patients with atopic dermatitis in Japan: results from a real-world, point-in-time, survey of physicians and patients

OBJECTIVE

Itch is a common symptom of atopic dermatitis (AD), however, there is limited evidence of the frequency and association of skin pain alongside itch. This study assessed the incremental dual burden and impact of itch and skin pain on satisfaction, quality of life and work productivity in patients with AD in Japan.

METHODS

Data were drawn from the 2020 Adelphi AD Disease Specific Programme, a point-in-time survey of dermatologists (n = 56) and their patients with history of moderate/severe AD (n = 265). Patients were grouped accordingly: no itch/skin pain (No I/SP, reference group, n = 89), itch/no skin pain (I-only, n = 71), and itch and skin pain (I + SP, n = 26). Descriptive analyses were performed alongside a range of regression models, dependent on outcome variables.

RESULTS

I + SP patients had a 4.97-point worse POEM score (p = .005) and 14.5% more overall work impairment (p = .034) versus the reference group. I-only and I + SP patients were 8.92 and 23.5 times more likely, respectively, to experience sleep disruption on a day-to-day basis (both p < .001). I + SP patients were 4.6 times more likely to be bothered by their symptoms (p = .034), had a mean EASI score 6.7 points higher (p = .008) and had 1.39 more areas affected (p = .001). I + SP patients were 7.26 times more likely to express dissatisfaction with lack of improvement in their condition and 8 times more likely to be dissatisfied with convenience of treatment (both p < .05).

CONCLUSION

This dissatisfaction, alongside variations in reported symptomatic burdens, suggests that physicians could consider alternative and/or novel therapeutic approaches for the management of both itch and skin pain.

The Role of KEAP1-NRF2 System in Atopic Dermatitis and Psoriasis

The Kelch-like erythroid cell-derived protein with cap‘n’collar homology-associated protein 1 (KEAP1)-nuclear factor erythroid-2-related factor 2 (NRF2) system, a thiol-based sensor-effector apparatus, exerts antioxidative and anti-inflammatory effects and maintains skin homeostasis. Thus, NRF2 activation appears to be a promising treatment option for various skin diseases. However, NRF2-mediated defense responses may deteriorate skin inflammation in a context-dependent manner. Atopic dermatitis (AD) and psoriasis are two common chronic inflammatory skin diseases caused by a defective skin barrier, dysregulated immune responses, genetic predispositions, and environmental factors. This review focuses on the role of the KEAP1-NRF2 system in the pathophysiology of AD and psoriasis and the therapeutic approaches that utilize this system.

Immunological Changes of Basophil Hyperreactivity to Sweat in Patients With Well-Controlled Atopic Dermatitis

Background

Sweat aggravates atopic dermatitis (AD). In patients with AD, type-I hypersensitivity to sweat may be shown by histamine release from patients’ basophils in response to the semi-purified sweat antigen (QR), and the presence of specific immunoglobulin E (IgE) binding to MGL_1304, the component of QR. However, there has been no information on the immunological changes of type-I hypersensitivity to the sweat antigen in patients with well-controlled AD using topical corticosteroids (TCSs) and/or biologics as treatments.

Method

Histamine-releasing tests using patients’ basophils and QR and the detection of serum IgE against MGL_1304 and mite allergen Der f 1 were performed in patients with AD who were well controlled by topical TCS with/without dupilumab for 53–96 weeks.

Results

In total, 14 patients were enrolled. Seven patients received TCS therapy alone (TCS group), and seven patients received TCS with dupilumab therapy (dupilumab group). In all participants, the level of specific IgE against MGL_1304 decreased after treatments, but histamine release from basophils in response to QR did not show a statistically significant reduction; rather, it increased. In the dupilumab group, all changes in histamine release induced by QR (increase), the IgE level against MGL_1304 (decrease), and that against Der f 1 (decrease) were statistically significant, whereas the TCS group showed no significant change in any of them.

Conclusion

The well-controlled condition for 53–96 weeks resulted in no reduction of the hyperreactivity of basophils against in patients with AD, even with the treatment with dupilumab. This study suggests persistent basophil hyperreactivity to sweat antigen over a year or longer.

Aberrant serine protease activities in atopic dermatitis

Atopic dermatitis (AD) is a chronic inflammatory skin disease; the three major factors responsible for AD, i.e., epidermal barrier dysfunction, allergic inflammation, and itching, interact with each other to form a pathological condition. Excessive protease activities are characteristic abnormalities that affect the epidermal barrier in patients with AD. In normal skin, epidermal serine protease activities are controlled by kallikrein-related peptidases (KLKs) and their inhibitors, including lympho-epithelial Kazal-type-related inhibitor (LEKTI). In AD lesions, KLKs are excessively expressed, which results in the enhancement of epidermal serine protease activities and facilitates the invasion by allergens and microorganisms. In addition, some KLKs can activate protease-activated receptor 2 (PAR2) in epidermal keratinocytes and peripheral nerves, resulting in the induction of inflammation and itching. Furthermore, in AD patients with single nucleotide polymorphism (SNP) such as E420K and D386N of SPINK5 which encodes LEKTI, LEKTI function is attenuated, resulting in the activation of KLKs and easy invasion by allergens and microorganisms. Further analysis is needed to elucidate the detailed mechanism underlying the control of serine protease activities, which may lead to the development of new therapeutic and prophylactic agents for AD.

Role of Basophils in a Broad Spectrum of Disorders

Basophils are the rarest granulocytes and have long been overlooked in immunological research due to their rarity and similarities with tissue-resident mast cells. In the last two decades, non-redundant functions of basophils have been clarified or implicated in a broad spectrum of immune responses, particularly by virtue of the development of novel analytical tools for basophils. Basophils infiltrate inflamed tissues of patients with various disorders, even though they circulate in the bloodstream under homeostatic conditions. Depletion of basophils results in the amelioration or exaggeration of inflammation, depending on models of disease, indicating basophils can play either beneficial or deleterious roles in a context-dependent manner. In this review, we summarize the recent findings of basophil pathophysiology under various conditions in mice and humans, including allergy, autoimmunity, tumors, tissue repair, fibrosis, and COVID-19. Further mechanistic studies on basophil biology could lead to the identification of novel biomarkers or therapeutic targets in a broad range of diseases.

Peripheral itch sensitization in atopic dermatitis

Atopic dermatitis is a skin disorder caused by skin dryness and barrier dysfunction, resulting in skin inflammation and chronic itch (or pruritus). The pathogenesis of atopic dermatitis is thought to be initiated by a lowering of the itch threshold due to dry skin. This lowering of the itch threshold is at least partially due to the increase in intraepidermal nerve fibers and sensitization of sensory nerves by interleukin (IL)-33 produced and secreted by keratinocytes. Such skin is easily prone to itch due to mechanical stimuli, such as rubbing of clothing and chemical stimuli from itch mediators. In patients with atopic dermatitis, once itch occurs, further itch is induced by scratching, and the associated scratching breaks down the skin barrier. Disruption of the skin barrier allows entry into the epidermis of external foreign substances, such as allergens derived from house dust mites, leading to an increased induction of type 2 inflammatory responses. As a result, type 2 cytokines IL-4, IL-13, and IL-31 are mainly secreted by Th2 cells, and their action on sensory nerve fibers causes further itch sensitization. These sequences of events are thought to occur simultaneously in patients with atopic dermatitis, leading to a vicious itch-scratch cycle. This vicious cycle becomes a negative spiral that leads to disease burden. Therefore, controlling itch is essential for the treatment of atopic dermatitis. In this review, we summarize and discuss advances in the mechanisms of peripheral itch sensitization in atopic dermatitis, focusing on skin barrier-neuro-immune triadic connectivity.

Polymorphisms of the filaggrin gene are associated with atopic dermatitis in the Caucasian population of Central Russia

Association of the filaggrin (FLG) gene with atopic dermatitis (AD) in Caucasians from Central Russia was studied in the sample of 700 patients and 612 controls. In total ten SNPs of the gene (rs61816761, rs12130219, rs77199844, rs558269137, rs4363385, rs12144049, rs471144, rs6661961, rs10888499, rs3126085), their haplotypes and interlocus interactions were analyzed using logistic regression. The functional effects of the AD risk candidate loci and their proxies (136 SNPs) were evaluated by in silico analysis. All analyzed SNPs were associated with AD: two SNPs (rs3126085 and rs12144049) manifested the independent association, nine SNPs were associated within 30 haplotypes, and seven SNPs showed interlocus interaction effects within ten most significant epistatic models. Alleles A rs3126085 and C rs12144049 were associated with a higher risk of AD according to the allelic (ORs being 1.75, p_perm = 0.002 and 1.45, p_perm = 0.011 respectively), additive (ORs being 1.69, p_perm = 0.004 and 1.47, p_perm = 0.011 respectively) and dominant (ORs being 1.79, p_perm = 0.004 and 1.63, p_perm = 0.005 respectively) genetic models. Three haplotypes, GT[rs3126085-rs12144049] (OR = 0.60), GGT[rs61816761-rs3126085-rs12144049] (OR = 0.59), and AWGGT[rs12130219-rs558269137-rs61816761-rs3126085-rs12144049] (OR = 0.63) demonstrated the protective effect (p_perm = 0.001). The in silico analysis suggested that the AD risk variants and their proxies apparently produce various effects on 38 genes in various tissue/organs (including 20 genes in the skin). The biological process enrichment analyses suggest that the target AD candidate genes influence the formation of the cornified envelope, keratinization and cornification, and more than twenty other pathways related to skin development, programmed cell death, and regulation of water loss via skin.

Role of ERK Pathway in the Pathogenesis of Atopic Dermatitis and Its Potential as a Therapeutic Target

Atopic dermatitis (AD) is an eczematous skin disorder characterized by type 2 inflammation, barrier disruption, and intense itch. In addition to type 2 cytokines, many other cytokines, such as interferon gamma (IFN-γ), interleukin 17 (IL-17), and interleukin 22 (IL-22), play roles in the pathogenesis of AD. It has been reported that the extracellular signal-regulated kinase (ERK) is downstream of such cytokines. However, the involvement of the ERK pathway in the pathogenesis of AD has not yet been investigated. We examined the expression of p-ERK in mouse and human AD skin. We also investigated the effects of the topical application of an ERK inhibitor on the dermatitis score, transepidermal water loss (TEWL), histological change, and expression of filaggrin, using an AD-like NC/Nga murine model. The effects of an ERK inhibitor on filaggrin expression in normal human epidermal keratinocytes (NHEKs) and on chemokine production from bone marrow-derived dendritic cells (BMDCs) were also evaluated. p-ERK was highly expressed in mouse and human AD skin. Topical application of an ERK inhibitor alleviated the clinical symptoms, histological changes, TEWL, and decrease in expression of filaggrin in the AD-like NC/Nga murine model. The ERK inhibitor also restored the IL-4 induced reduction in the expression of filaggrin in NHEK, and inhibited chemokine production from BMDC induced by IL-4. These results indicate that the ERK pathway is involved in the pathogenesis of AD, and suggest that the ERK pathway has potential as a therapeutic target for AD in the future.

Pruritus: A Sensory Symptom Generated in Cutaneous Immuno-Neuronal Crosstalk

Pruritus or itch generated in the skin is one of the most widespread symptoms associated with various dermatological and systemic (immunological) conditions. Although many details about the molecular mechanisms of the development of both acute and chronic itch were uncovered in the last 2 decades, our understanding is still incomplete and the clinical management of pruritic conditions is one of the biggest challenges in daily dermatological practice. Recent research revealed molecular interactions between pruriceptive sensory neurons and surrounding cutaneous cell types including keratinocytes, as well as resident and transient cells of innate and adaptive immunity. Especially in inflammatory conditions, these cutaneous cells can produce various mediators, which can contribute to the excitation of pruriceptive sensory fibers resulting in itch sensation. There also exists significant communication in the opposite direction: sensory neurons can release mediators that maintain an inflamed, pruritic tissue-environment. In this review, we summarize the current knowledge about the sensory transduction of pruritus detailing the local intercellular interactions that generate itch. We especially emphasize the role of various pruritic mediators in the bidirectional crosstalk between cutaneous non-neuronal cells and sensory fibers. We also list various dermatoses and immunological conditions associated with itch, and discuss the potential immune-neuronal interactions promoting the development of pruritus in the particular diseases. These data may unveil putative new targets for antipruritic pharmacological interventions.

Effectiveness of Cimetidine as Adjuvant Therapy in the Treatment of Acute-Extrinsic Atopic Dermatitis: A Double-Blind Randomized Controlled Trial

Introduction

Acute extrinsic atopic dermatitis (AD) requires long-term treatment. Cimetidine could be used as an adjuvant therapy for acute-extrinsic AD due to immunomodulatory effects. This study aims to assess the effectiveness of cimetidine as an adjuvant to standard treatment in acute extrinsic AD.

Methods

This is a double-blind randomized controlled trial involving 26 AD patients aged 12–60 years from 2017 to 2020. Effectiveness of cimetidine was assessed by comparing SCORing Atopic Dermatitis (SCORAD) and objective SCORAD changes in both groups at week 2, 4, 6, and 8. Serum levels of immunoglobulin E (IgE), interferon (IFN)-γ, interleukin (IL)-12, and IL-4 were also documented.

Results

Significant differences were observed in SCORAD changes at week 2, 4, 6, and 8 (p = 0.004; p = 0.001; p < 0.001; and p < 0.001 respectively), objective SCORAD changes at week 2, 4, 6, and 8 (p = 0.004, p = 0.001, p < 0.001, and p < 0.001 respectively), and IgE level changes at week 8 (p = 0.002) between the two groups. However, there were no significant changes in IFN-γ, IL-12, and IL-4 levels between the two groups.

Conclusion

Cimetidine is a safe and effective adjuvant therapy for acute-extrinsic AD.

Trial Registration

NCT04018131.

The role of sodium hypochlorite in atopic dermatitis therapy: a narrative review

Atopic dermatitis (AD) is a common skin disorder, especially in the pediatric population. Genetic and immunological factors, epidermal barrier defect, as well as skin microbiota imbalance with increased colonization by Staphylococcus aureus (SA) are involved in the pathogenesis of the disease. One of the AD topical treatments is sodium hypochlorite (NaOCl) as a 0.005% water bath solution. This substance has been used for years as an antiseptic preparation. Studies show that NaOCl has an antimicrobial effect but probably at higher concentrations than those used in AD treatment. Nevertheless, many research studies confirm the anti-inflammatory and anti-itching effects of NaOCl, which contributes to clinical improvement in AD patients as well as reducing the need for local steroids and antibiotics. Bleach baths seem to be a well tolerated, cheap, and easily available therapy. However, research still should be continued to evaluate its antibacterial efficacy, anti-inflammatory effects, and safety.

Atopic dermatitis in psychodermatology: a concise review for dermatologists

Atopic Dermatitis (AD) is a chronic disease of the skin with significant pruritus and phases of exacerbation and remission. The hallmarks of AD are changes in the epithelial barrier and chronic inflammation. This condition is associated with an increased risk of developing mental disorders such as depression, anxiety, and suicidal ideation. It has been proposed that psychological stress may impact on immunological factors with an up-regulation of mediating neuropeptides at the level of central nervous system and secondary involvement of endocrine glands, peripheral nervous system, and immune resident skin cells. This article provides a concise review for dermatologists on the psychodermatology of AD, in order to highlight the putative common pathways between the dermatologic and mental health issues in this illness.

Possible Role of Leptin in Atopic Dermatitis: A Literature Review

Atopic dermatitis (AD) is the most frequent chronic inflammatory skin disease, and its incidence has been rapidly increasing in developed countries in the last years. AD presents a high degree of heterogeneity due to biases and confounding factors such as age range, sex, or ethnicity. For those reasons, the search for new biomarkers is crucial. At the same time, obesity, which is a global health problem, has also increased over the years. It has been associated with many pathophysiological states, including skin diseases such as AD, mostly in childhood. Obesity promotes a low grade inflammation driven by many different cytokines and adipokines, including leptin, which has a key role in many other diseases due to its pleiotropic effects. Leptin also has a role in both skin and allergic diseases very related to AD. Thus, this adipokine could have an important role in the pathogenesis of AD, especially in its chronicity. Despite the limited literature available, there is some evidence that leads us to consider leptin as an important adipokine in this skin disease. For this reason, here we have reviewed the role of leptin in the pathophysiology of AD.

Advances in Atopic Dermatitis in 2019-2020: Endotypes from skin barrier, ethnicity, properties of antigen, cytokine profiles, microbiome, and engagement of immune cells

Key research advances in atopic dermatitis (AD) suggest the complexity of its endotypes. A comprehensive serum biomarker panel revealed at least four types of AD. Some represent classic TH2-dominant AD with filaggrin mutations commonly reported in Europeans, a simultaneously activated multipolar axes of cytokines often reported in Asians, and an intrinsic type characterized by TH2-inferiority. Innate lymphoid cells, including NK cells, NKT cells, and fibroblasts, play a role in AD development and heterogeneity. Here, we discuss the endotypes of AD from the perspective of antigen types (hapten vs. protein antigens), barrier function, and a novel set of immune cells. Endotypic stratification of AD may lead to the development of customized therapeutic strategies in the future.

Autophagy in skin barrier and immune-related skin diseases

Autophagy is a process which is highly conserved in eukaryotes to degrade or recycle cytoplasmic components through lysosomes to maintain cellular homeostasis. Recent studies have shown that autophagy also plays critical roles in cell apoptosis, inflammation, pathogen clearance, and so on under stressed conditions and thereby has been linked to a variety of human disorders. The skin is the largest organ of the body and serves as the first line of defense against environmental insult. Skin as a nutrient-poor environment requires recycling of limited resources via the autophagy machinery to maintain homeostasis. Therefore, dysregulation of autophagy has been linked to skin diseases. In this review, we describe the molecular machinery and regulation of autophagy, discuss its role in keratinocytes and skin barrier, skin immune cells, and immune-related skin diseases including autoimmune skin disorders, allergic skin diseases, infectious skin disorders, and antitumor immunity against skin tumor. Finally, we highlight the potential of autophagy as a therapeutic target for immune-related skin diseases, and delivery of autophagy-related molecules (such as inducers, inhibitors, or nucleic acid molecules) by virtue of physical materials (such as nanoparticles) or biological materials (such as peptides) to skin topically may obtain clinical benefits in immune-related skin diseases. Moreover, developing autophagy-related gene product-based biomarkers may be promising to diagnose immune-related skin diseases.

TRPV1 mediates itch-associated scratching and skin barrier dysfunction in DNFB-induced atopic dermatitis mice

In chronic pruritic diseases such as atopic dermatitis (AD), pruritus and skin lesions are exacerbated by scratching in clinical and experimental settings. TRPV1 is known to mediate itch and neurogenic inflammation, but the role of TRPV1 in itch-associated scratching in AD is poorly understood. In this study, we examined the efficacy of cutting off nails and TRPV1 antagonist, ruthenium red (RR) in a murine model of AD induced by DNFB and further investigated the underlying mechanism. Nail clipping or RR could markedly ameliorate the general AD-like symptoms as manifested by the reduced clinical severity of dermatitis, IgE and Th2-related cytokine levels, and mast cell degranulation. Moreover, scratching behaviour, the levels of pruritogenic mediators, including HIS, TSLP, IL-31 and SP, and skin pH and TEWL were all significantly decreased in nail clipping or RR-treated mice, suggesting a reduction in itch-associated scratching and skin barrier defects. Immunofluorescence staining and Western blot results revealed that antipruritic effect of nail clipping or RR in AD may be explained, at least in part, by the suppression of TRPV1 activation. In summary, these data show that TRPV1 mediates itch-associated scratching and subsequent skin barrier defects, suggesting its potential as a therapeutic target in AD.

Asivatrep, a TRPV1 antagonist, for the topical treatment of atopic dermatitis: Phase 3, randomized, vehicle-controlled study (CAPTAIN-AD)

BACKGROUND

Asivatrep is a potent and selective antagonist of transient receptor potential vanilloid subfamily V member 1 (TRPV1), which plays an important role in itch and inflammation in atopic dermatitis (AD).

OBJECTIVE

This current study aimed to evaluate the efficacy and safety of asivatrep cream in patients with AD.

METHODS

For this phase 3 double-blind, vehicle-controlled study, patients aged ≥12 years with mild to moderate AD were enrolled and randomly assigned 2:1 to the 1.0% asivatrep or vehicle group for 8 weeks of twice-daily application (n = 240). The primary end point was the proportion of patients with an Investigator's Global Assessment score (IGA) of 0 or 1 at week 8. Standard safety assessments were conducted.

RESULTS

At week 8, significantly more patients in the asivatrep group (36.0%) than in the vehicle group (12.8%) had IGA scores of 0 or 1 (P < .001); significantly more had ≥2 points of improvement on the IGA from baseline score (20.3% vs 7.7%; P = .01). The mean percentage reduction in the Eczema Area and Severity Index (EASI) score was 44.3% for the asivatrep group and 21.4% for the vehicle group at week 8 (P < .001). Significantly more asivatrep-treated patients experienced an improvement of at least 50%, 75%, and 90% on the EASI than the vehicle group. The mean ± SD change in the pruritus visual analog scale score at week 8 was -2.3 ± 2.4 for the asivatrep group and -1.5 ± 2.4 for the vehicle group (P = .02). No significant safety issues were reported.

CONCLUSION

Asivatrep improved clinical signs and symptoms of AD and was well tolerated.

A Novel In Vitro Assay Using Human iPSC-Derived Sensory Neurons to Evaluate the Effects of External Chemicals on Neuronal Morphology: Possible Implications in the Prediction of Abnormal Skin Sensation

Neuronal morphological changes in the epidermis are considered to be one of causes of abnormal skin sensations in dry skin-based skin diseases. The present study aimed to develop an in vitro model optimised for human skin to test the external factors that lead to its exacerbation. Human-induced pluripotent stem cell-derived sensory neurons (hiPSC-SNs) were used as a model of human sensory neurons. The effects of chemical substances on these neurons were evaluated by observing the elongation of nerve fibers, incidence of blebs (bead-like swellings), and the expression of nicotinamide mononucleotide adenylyl transferase 2 (NMNAT2). The nerve fiber length increased upon exposure to two common cosmetic preservatives-methylparaben and phenoxyethanol-but not to benzo[a]pyrene, an air pollutant at the estimated concentrations in the epidermis. Furthermore, the incidence of blebs increased upon exposure to benzo[a]pyrene. However, there was a decrease in the expression of NMNAT2 in nerve fibers, suggesting degenerative changes. No such degeneration was found after methylparaben or phenoxyethanol at the estimated concentrations in the epidermis. These findings suggest that methylparaben and phenoxyethanol promote nerve elongation in hiPSC-SNs, whereas benzo[a]pyrene induces nerve degeneration. Such alterations may be at least partly involved in the onset and progression of sensitive skin.

Orengedokuto exerts anti-allergic effects via inhibition of effector T cell activation in a murine model of contact hypersensitivity

Orengedokuto (OGT) is a Kampo prescription that has been used for the treatment of inflammation, hypertension, gastrointestinal disorders, and liver and cerebrovascular diseases. It is also used for the treatment of skin diseases such as urticaria and atopic dermatitis. We previously studied its anti-allergic effects of OGT on the murine model of 2,4,6-trinitrochlorobenzene (TNCB)-induced contact hypersensitivity (CHS) and demonstrated that it significantly suppresses ear swelling in a dose-dependent manner. However, the mechanism underlying this activity remained unknown. Here, we sought to identify the mechanism involved. Using a murine model of TNCB-induced CHS, together with adoptive cell transfer experiments, we found that the anti-allergic effects of OGT may be due to the inhibition of effector T cell activation and not the induction and/or activation of regulatory T cells. Flow cytometry analysis revealed that oral administration of OGT suppressed the increase in CD8⁺CD44^highCD62L⁺ cell number in draining lymph nodes (dLNs) of mice sensitized with 5% TNCB. Additionally, ex vivo experiments confirmed the suppressive effect of OGT on the activation of effector T cells, as interferon-γ (IFN-γ) production by cultured lymphocytes obtained from 5% TNCB-sensitized mice and stimulated with anti-CD3ε and anti-CD28 monoclonal antibodies was reduced by OGT administration. In conclusion, our finding suggests that OGT exerts anti-allergic effects by regulating the activation of effector T cells involved in inflammatory skin diseases such as atopic dermatitis.

Artemisia anomala Herba Alleviates 2,4-Dinitrochlorobenzene-Induced Atopic Dermatitis-Like Skin Lesions in Mice and the Production of Pro-Inflammatory Mediators in Tumor Necrosis Factor Alpha-/Interferon Gamma-Induced HaCaT Cells

Artemisia anomala S. Moore is a perennial herbaceous plant classified as Asteraceae of the genus Artemisia. Many species of Artemisia have been used as medicinal materials. Artemisia anomala S. Moore has been widely used in China to treat inflammatory diseases. However, the mechanism of its action on the keratinocyte inflammatory response is poorly understood. Here, we investigated the anti-inflammatory reaction of Artemisia anomala S. Moore ethanol extract (EAA) using human keratinocyte (HaCaT) cells, which involved investigating the nuclear factor kappa B (NF-κB), signal transducer, and activator of transcription-1 (STAT-1), as well as mitogen-activated protein kinase (MAPK) signaling pathways and atopic dermatitis-like skin lesions in mice. We elucidated the anti-inflammatory effects of EAA on tumor necrosis factor-α/interferon-γ (TNF-α/IFN-γ)-treated human keratinocyte cells and 2,4-dinitrochlorobenzene (DNCB)-induced atopic dermatitis (AD)-like mice. The levels of chemokines and cytokines (IL-8, IL-6, TARC, and RANTES) were determined by an enzyme-linked immunosorbent assay. The NF-κB, STAT-1, and MAPK signaling pathways in HaCaT cells were analyzed by western blotting. Thickening of the mice dorsal and ear skin was measured and inflammatory cell infiltration was observed by hematoxylin and eosin staining. Results showed that EAA suppressed IL-8, IL-6, TARC, and RANTES production. EAA inhibited nuclear translocation of NFκB and STAT-1, as well as reduced the levels of phosphorylated ERK MAPKs. EAA improved AD-like skin lesions in DNCB-treated mice. These findings suggest that EAA possesses stronger anti-inflammatory properties and can be useful as a functional food or candidate agent for AD.

Prospective, comparative clinical pilot study of cold atmospheric plasma device in the treatment of atopic dermatitis

Cold atmospheric plasma generates free radicals through the ionization of air at room temperature. Its effect and safety profile as a treatment modality for atopic dermatitis lesions have not been evaluated prospectively enough. We aimed to investigate the effect and safety of cold atmospheric plasma in patients with atopic dermatitis with a prospective pilot study. Cold atmospheric plasma treatment or sham control treatment were applied respectively in randomly assigned and symmetric skin lesions. Three treatment sessions were performed at weeks 0, 1, and 2. Clinical severity indices were assessed at weeks 0, 1, 2, and 4 after treatment. Additionally, the microbial characteristics of the lesions before and after treatments were analyzed. We included 22 patients with mild to moderate atopic dermatitis presented with symmetric lesions. We found that cold atmospheric plasma can alleviate the clinical severity of atopic dermatitis. Modified atopic dermatitis antecubital severity and eczema area and severity index score were significantly decreased in the treated group. Furthermore, scoring of atopic dermatitis score and pruritic visual analog scales significantly improved. Microbiome analysis revealed significantly reduced proportion of Staphylococcus aureus in the treated group. Cold atmospheric plasma can significantly improve mild and moderate atopic dermatitis without safety issues.

The Implications of Pruritogens in the Pathogenesis of Atopic Dermatitis

Atopic dermatitis (AD) is a prototypic inflammatory disease that presents with intense itching. The pathophysiology of AD is multifactorial, involving environmental factors, genetic susceptibility, skin barrier function, and immune responses. A recent understanding of pruritus transmission provides more information about the role of pruritogens in the pathogenesis of AD. There is evidence that pruritogens are not only responsible for eliciting pruritus, but also interact with immune cells and act as inflammatory mediators, which exacerbate the severity of AD. In this review, we discuss the interaction between pruritogens and inflammatory molecules and summarize the targeted therapies for AD.