Mechanistic insights into topical tacrolimus for the treatment of atopic dermatitis

Molecular and cellular mechanisms of itch sensation and the anti-itch drug targets

Itch is an uncomfortable feeling that evokes a desire to scratch. This protective reflex can effectively eliminate parasites that invade the skin. When itchy skin becomes severe or lasts for more than six weeks, it has deleterious effects on both quality of life and productivity. Despite decades of research, the complete molecular and cellular coding of chronic itch remains elusive. This persistent condition often defies treatment, including with antihistamines, and poses a significant societal challenge. Obtaining pathophysiological insights into the generation of chronic itch is essential for understanding its mechanisms and the development of innovative anti-itch medications. In this review we provide a systematic overview of the recent advancement in itch research, alongside the progress made in drug discovery within this field. We have examined the diversity and complexity of the classification and mechanisms underlying the complex sensation of itch. We have also delved into recent advancements in the field of itch mechanism research and how these findings hold potential for the development of new itch treatment medications. But the treatment of clinical itch symptoms still faces significant challenges. Future research needs to continue to delve deeper, not only to discover more itch-related pathways but also to explore how to improve treatment efficacy through multitarget or combination therapy.

Atopic dermatitis treatment: A comprehensive review of conventional and novel bioengineered approaches

Atopic dermatitis (AD) remains a challenging condition, with conventional treatments often leading to adverse effects and limited efficacy. This review explores the diverse landscape of AD treatments, encompassing conventional methods, novel topical and systemic therapies, and emerging bioengineered strategies. While conventional drug administration often requires high dosages or frequent administration, leading to adverse effects, targeted biologics have shown promise. Phototherapy and wet wrap therapy, while helpful, have limitations. Given these factors, the need for modern and effective therapeutic strategies for AD is pressing. Complementary or alternative therapies have garnered significant attention in recent years as a compelling treatment for AD. Among these, functionalized biomaterials and textiles with physicochemical, nanotechnology-based characteristics, or bioengineered features are some of the most common typical adjuvant therapies. The multifunctional-engineered biomaterials, as a new generation of biomedical materials, and stem cells, seem to hold tremendous promise for the treatment of dermatological diseases like AD. Biomaterials have seen great success, especially in various medical fields, due to their unique and adaptable characteristics. These materials, including collagen, PCL, and PLGA, offer unique advantages, such as biocompatibility, biodegradability, controlled drug release, and enhanced drug retention.

Atopic dermatitis: pathogenesis and therapeutic intervention

The skin serves as the first protective barrier for nonspecific immunity and encompasses a vast network of skin-associated immune cells. Atopic dermatitis (AD) is a prevalent inflammatory skin disease that affects individuals of all ages and races, with a complex pathogenesis intricately linked to genetic, environmental factors, skin barrier dysfunction as well as immune dysfunction. Individuals diagnosed with AD frequently exhibit genetic predispositions, characterized by mutations that impact the structural integrity of the skin barrier. This barrier dysfunction leads to the release of alarmins, activating the type 2 immune pathway and recruiting various immune cells to the skin, where they coordinate cutaneous immune responses. In this review, we summarize experimental models of AD and provide an overview of its pathogenesis and the therapeutic interventions. We focus on elucidating the intricate interplay between the immune system of the skin and the complex regulatory mechanisms, as well as commonly used treatments for AD, aiming to systematically understand the cellular and molecular crosstalk in AD-affected skin. Our overarching objective is to provide novel insights and inform potential clinical interventions to reduce the incidence and impact of AD.

Computational simulation on the study of Tacrolimus and its improved dermal retention using Poly(Ԑ-caprolactone) nanocapsules

Tacrolimus (TAC) is a drug from natural origin that can be used for topical application to control autoimmune skin diseases such as atopic dermatitis, psoriasis, and vitiligo. Computational simulation based on quantum mechanics theory by solving Schrödinger Equation for n-body problem may allow the theoretical calculation of drug geometry, charge distribution and dipole moment, electronic levels and molecular orbitals, electronic transitions, and vibrational transitions. Additionally, the development of novel nanotechnology-based delivery systems containing TAC can be an approach for reducing the dose applied topically, increasing dermal retention, and reducing the reported side effects due to the controlled release pattern. Firstly, this paper was devoted to obtaining the molecular, electronic, and vibrational data for TAC by using five semi-empirical (SE) methods and one Density Functional Theory (DFT) method in order to expand the knowledge about the drug properties by computational simulation. Then, this study was carried out to prepare TAC-loaded poly(ԑ-caprolactone) nanocapsules by interfacial polymer deposition following solvent displacement and investigate the in vitro drug permeation using the Franz diffusion cell and the photoacoustic spectroscopy. Computational simulations were compared in the three schemes SE/SE, SE/DFT, and DFT/DFT, where the first method represented the procedure used for geometry optimization and the second one was performed to extract electronic and vibrational properties. Computational data showed correspondence with TAC geometry description and electronic properties, with few differences in HOMO - LUMO gap (Δ) and dipole values. The SE/DFT and DFT/DFT methods presented a better drug description for the UV-Vis, Infrared, and Raman spectra with low deviation from experimental values. Franz cell model demonstrated that TAC was more delivered across the Strat-M® membrane from the solution than the drug-loaded poly(ԑ-caprolactone) nanocapsules. Photoacoustic spectroscopy assay revealed that these nanocapsules remained more retained into the Strat-M® membranes, which is desirable for the topical application.

Dual effect of tacrolimus on mast cell-mediated allergy and inflammation through Mas-related G protein-coupled receptor X2

BACKGROUND

Topical tacrolimus, although widely used in the treatment of dermatoses, presents with an immediate irritation on initial application resembling a pseudo-allergic reaction. Mas-related G protein-coupled receptor X2 (MRGPRX2) in mast cells (MCs) mediates drug-induced pseudo-allergic reaction and immunoglobulin E (IgE)-independent pruritis in chronic skin diseases. However, the immunosuppression mechanism of tacrolimus on MCs via MRGPRX2 has not been reported.

OBJECTIVE

To investigate the role of MRGPRX2 and the mechanism of action of tacrolimus on its short-term and long-term applications.

METHODS

Wild-type mice, KitW-sh/W-sh mice, and MrgprB2-deficient (MUT) mice were used to study the effect of tacrolimus on in vivo anaphylaxis model. LAD2 cells and MRGPRX2-knockdown LAD2 cells were specifically used to derive the associated mechanism of the tacrolimus effect.

RESULTS

Short-term application of tacrolimus triggers IgE-independent activation of MCs via MRGPRX2/B2 in both in vivo and in vitro experiments. Tacrolimus binds to MRGPRX2, which was verified by fluorescently labeled tacrolimus in cells. On long-term treatment with tacrolimus, the initial allergic reaction fades away corresponding with the downregulation of MRGPRX2, which leads to decreased release of inflammatory cytokines (P < 0.05 to P < 0.001).

CONCLUSION

Short-term treatment with tacrolimus induces pseudo-allergic reaction via MRGPRX2/B2 in MCs, whereas long-term treatment downregulates expression of MRGPRX2/B2, which may contribute to its potent immunosuppressive effect in the treatment of various skin diseases.

Protein kinases: drug targets for immunological disorders

Protein kinases play a major role in cellular activation processes, including signal transduction by diverse immunoreceptors. Given their roles in cell growth and death and in the production of inflammatory mediators, targeting kinases has proven to be an effective treatment strategy, initially as anticancer therapies, but shortly thereafter in immune-mediated diseases. Herein, we provide an overview of the status of small molecule inhibitors specifically generated to target protein kinases relevant to immune cell function, with an emphasis on those approved for the treatment of immune-mediated diseases. The development of inhibitors of Janus kinases that target cytokine receptor signalling has been a particularly active area, with Janus kinase inhibitors being approved for the treatment of multiple autoimmune and allergic diseases as well as COVID-19. In addition, TEC family kinase inhibitors (including Bruton's tyrosine kinase inhibitors) targeting antigen receptor signalling have been approved for haematological malignancies and graft versus host disease. This experience provides multiple important lessons regarding the importance (or not) of selectivity and the limits to which genetic information informs efficacy and safety. Many new agents are being generated, along with new approaches for targeting kinases.

Anti-inflammatory and biologic drugs for atopic dermatitis: a therapeutic approach in children and adolescents

Atopic dermatitis (AD) is a chronic inflammatory disease with a heterogeneous pathogenesis correlated with dysregulation of the immune system and a prevalence of the T2-mediated immune pathway. Recent understanding of the pathogenesis of AD has allowed the development of new drugs targeting different mechanisms and cytokines that have changed the treatment approach. The aim of this review is to update knowledge on the standard of care and recent advancements in the control of skin inflammation. In light of recent guidelines, we report on the clinical efficacy of novel treatments, with special attention to situations where biologics and small molecules are involved.

Eosinophilic gastroenteritis: Pathogenesis, diagnosis, and treatment

ABSTRACT

Eosinophilic gastroenteritis (EGE) is a gastrointestinal disorder of unclear etiology that is characterized by eosinophilic infiltration of the stomach and small intestine, and consists of mucosal, muscular, and serosal subtypes. Eosinophilic infiltration of the gastrointestinal tract is a fundamental histopathological characteristic of EGE and is driven by several T-helper type 2 (Th2)-dependent cytokines and induced by food allergy. Due to the lack of a diagnostic gold standard, EGE has a high rate of delayed diagnosis or misdiagnosis. However, several new diagnostic strategies have been developed, such as novel genetic biomarkers and imaging tests. Although dietary therapy and corticosteroids remain the common choices for EGE treatment, recent decades have seen the emergence of novel treatment alternatives, such as biologics that target particular molecules involved in the pathogenic process. Preliminary investigations and clinical trials have demonstrated the efficacy of biologics and provided additional insights for the era of refractory or corticosteroid-dependent EGE biologics.

IL-33-induced keratoconjunctivitis is mediated by group 2 innate lymphoid cells in mice

BACKGROUND

Interleukin-33 (IL-33) is involved in type 2 innate immunity by inducing type 2 cytokines, such as IL-5 and IL-13, through the activation of group 2 innate lymphoid cells (ILC2s) or T helper 2 (Th2) cells. We previously reported that mice overexpressing IL-33 (IL-33Tg) in the cornea and conjunctiva spontaneously develop atopic keratoconjunctivitis-like inflammation. Despite previous studies, it is not fully understood what types of immune cells contribute to the disease process of IL-33-induced keratoconjunctivitis.

METHODS

To defect Th2 cells, IL-33Tg mice were crossed with Rag2KO mice. To defect ILC2s, IL-33Tg mice received bone marrow transplantations from B6.C3(Cg)-Rorasg/J mice that lacked ILC2. Immunostaining techniques were used to determine where ILC2 is distributed in the cornea and conjunctiva. We analyzed the transcriptomes of ILC2 from the conjunctiva by using single-cell RNA-seq analysis. To investigate whether tacrolimus reduces type 2 cytokine production by ILC2, ILC2 was cultured with tacrolimus, and the percentage of cytokine-producing ILC2 was examined. To investigate whether tacrolimus can inhibit IL-33-induced keratoconjunctivitis in vivo, IL-33Tg mice were treated with tacrolimus eye drops.

RESULTS

ILC2 infiltrated the conjunctival epithelium and subepithelial tissue. Keratoconjunctivitis developed spontaneously in Rag2KO/IL-33Tg mice, but keratoconjunctivitis was abolished in IL-33Tg mice lacking ILC2. ILC2 was not a uniform cluster but a heterogeneous cluster. Tacrolimus inhibited cytokine production from ILC2s in vitro, and tacrolimus eye drops inhibited keratoconjunctivitis in IL-33Tg mice in vivo.

CONCLUSIONS

ILC2 plays a pivotal role in IL-33-induced keratoconjunctivitis in mice.

Narrative review on the management of moderate-severe atopic dermatitis in pediatric age of the Italian Society of Pediatric Allergology and Immunology (SIAIP), of the Italian Society of Pediatric Dermatology (SIDerP) and of the Italian Society of Pediatrics (SIP)

Currently, there are a few detailed guidelines on the overall management of children and adolescents with moderate-severe atopic dermatitis. AD ​​is a complex disease presenting with different clinical phenotypes, which require an individualized and multidisciplinary approach. Therefore, appropriate interaction between primary care pediatricians, pediatric allergists, and pediatric dermatologists is crucial to finding the best management strategy. In this manuscript, members of the Italian Society of Pediatric Allergology and Immunology (SIAIP), the Italian Society of Pediatric Dermatology (SIDerP), and the Italian Society of Pediatrics (SIP) with expertise in the management of moderate-severe atopic dermatitis have reviewed the latest scientific evidence in the field. This narrative review aims to define a pathway to appropriately managing children and adolescents with moderate-severe atopic dermatitis.

Comprehensive Phytochemical Profiling of Polyherbal Divya-Kayakalp-Vati and Divya-Kayakalp-Oil and Their Combined Efficacy in Mouse Model of Atopic Dermatitis-Like Inflammation Through Regulation of Cytokines

PURPOSE

Atopic dermatitis (AD) is a chronic inflammatory disease that varies in signs and symptoms in different individuals. General symptoms include dryness of the skin, itching, and development of red to brownish-gray patches. Divya-Kayakalp-Vati (DKV) and -Oil (DKO) are Indian polyherbal compositions prescribed for treating inflammatory skin diseases. In the present study, we evaluated the anti-inflammatory efficacy of DKV and DKO co-treatment (DKV-O) in ameliorating Oxazolone (OXA)-stimulated AD-like inflammation and pro-inflammatory cytokine release in a Swiss albino mouse model.

METHODS

Phytochemical profiling of the DKV and DKO were done using Liquid Chromatography-Mass Spectroscopy (LC-MS) QToF. Swiss albino mice were sensitized for 7 days and treated with OXA in their ear region. Stimulated and control animals were orally treated with DKV and topically with DKO. Anti-inflammatory efficacy of DKV-O was determined in OXA-treated animals through physiological, histopathological, and biochemical parameter analysis.

RESULTS

DKV and DKO formulations individually contained 39 and 59 phytochemicals, respectively. Many of the phytochemicals have been reported to have anti-inflammatory activities. In the OXA-sensitized Swiss albino mice, combined treatment with DKV-O, and separately with Dexamethasone (positive control) significantly reduced the OXA-stimulated ear edema, biopsy weight, and epidermal thickness. DKV-O further reduced OXA-stimulated induction of inflammatory lesions, neutrophil influx, and release of Interleukin (IL)-1β, IL-6, tumor necrosis factor-α, and myeloperoxidase.

CONCLUSION

Finally, DKV-O co-treatment showed good pharmacological effects in ameliorating AD-like inflammation through the modulation of inflammatory cell influx and release of soluble mediators. Therefore, DKV-O treatment can be used as a suitable polyherbal therapeutic against AD-like inflammatory diseases.

Stratification of atopic dermatitis patients by patterns of response to proactive therapy with topical tacrolimus: low serum IgE levels and inadequately controlled disease activity at the start of treatment predict its failure

PURPOSE

Topical calcineurin inhibitors (TCIs) are an important anti-inflammatory drug for treating atopic dermatitis (AD). However, those treatment responses are variable. In this study, we stratified AD patients by patterns of response to remission maintenance therapy (proactive therapy) with topical tacrolimus, a typical TCI. Thereafter, we explored patient features that predict the success or failure of proactive therapy using TCI (TCI proactive therapy).

METHODS

A single-arm open-label clinical study aimed to evaluate the efficacy of TCI proactive therapy was conducted in 31 patients with AD. Patients were treated with TCS to induce remission (remission-induction period) followed by daily TCI ointment (0.1% tacrolimus) application for 4 weeks (maintenance therapy period), and twice-weekly application for 12 weeks (proactive therapy period). Based on its results, treatment outcomes were correlated with the patients' clinical and laboratory findings.

RESULTS

Of the 31 patients enrolled in the study, 21 successfully completed maintenance therapy (TCI responders). Among them, 13 completed (proactive-completed group) and 8 failed proactive therapy (proactive-dropout group). At the beginning of maintenance therapy, the serum IgE level was significantly higher in the TCI responders than in those who failed maintenance therapy (p = 0.049). At the beginning of proactive therapy, the mean-SCORing Atopic Dermatitis (SCORAD) score was significantly different between the proactive-completed (11.7 ± 4.6) and proactive-dropout (16.6 ± 4.2) groups (p = 0.025). In proactive-dropout group patients, worsened disease activity correlated well with the elevation of serum lactate dehydrogenase (LDH) and Thymus and activation-regulated chemokine (TARC) levels and peripheral eosinophil count.

CONCLUSION

AD patients were stratified into three different response patterns to TCI proactive therapy. Patients with less involvement of IgE in the pathogenesis and inadequate remission induction by TCS may not be expected to respond well to TCI proactive therapy.Key messagesAD patients can be stratified into three types according to their pattern of responsiveness to TCI proactive therapy.The efficacy of TCI proactive therapy is lower in AD patients with lower serum IgE levels.TCI proactive therapy should be done after the achievement of adequate remission induction by TCS.

Baricitinib for the treatment of atopic dermatitis

Atopic dermatitis is a common, chronic and recurrent inflammatory skin disease, which often appears in childhood but can last into adulthood. It negatively impacts patients, their families and society in general. There is a therapeutic unmet need, with patients requiring new drugs that are safe and effective. The increasing knowledge of the pathophysiology of AD and the role of the Janus kinase (JAK) and signal transducer and activator of transcription (STAT) pathway in the development and maintenance of AD, has led to the development of agents blocking this intracellular signaling pathway, the JAK inhibitors. Baricitinib shows high selectivity for JAK1 and JAK2, making it appealing for the treatment of this condition. Phase II and phase III trials evaluated the efficacy and safety of baricitinib in the treatment of AD, and the results have been encouraging, showing a good efficacy and a favorable safety and tolerability profile. At the end of 2020, EMA approved baricitinib for the treatment of adult patients with moderate-to-severe atopic dermatitis who are candidates for systemic therapy, increasing the therapeutic option for this debilitating disease.

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.

Novel Targeted Biological Agents for the Treatment of Atopic Dermatitis

Atopic dermatitis (AD) is a common inflammatory dermatologic disease clinically characterized by intense itch, recurrent eczematous lesions, and a chronic or relapsing disease course. Mild-to-moderate AD can be controlled by using moisturizers and topical immunomodulators such as topical corticosteroids and calcineurin inhibitors. If topical therapies fail, phototherapy and systemic immunosuppressant therapies, such as ciclosporin, methotrexate, and azathioprine, can be considered. However, relapse and side effects could still occur. The pathogenesis of AD involves epidermal barrier dysfunction, skin microbiome abnormalities, and cutaneous inflammation. Inflammatory mediators, such as interleukin (IL)-4, IL-13, IL-31, IL-33, IL-17, IL-23, and thymic stromal lymphopoietin, are involved in AD development. Therefore, a series of biological agents targeting these cytokines are promising approaches for treating AD. Dupilumab is the first biological agent approved for the treatment of AD in patients aged 6 years and older in the United States. Tralokinumab, lebrikizumab, and nemolizumab have also been confirmed to have significant efficacy against AD in phase III or IIb clinical trials. Also, fezakinumab was effective in severe AD patients in a phase IIa trial. However, phase II trials of ustekinumab, tezepelumab, etokimab, secukinumab, and omalizumab have failed to meet their primary endpoints. Phase II trials of GBR 830 and KHK 4083 are ongoing. In general, further studies are needed to explore new therapeutic targets and improve the efficacy of biological agents.

Tacrolimus (FK506) treatment protects allergen-, IL-5- and IL-13-induced mucosal eosinophilia

Eosinophils are a common clinical feature associated with chronic allergic diseases, and elemental diets, systemic steroids, anti-IL-5 and anti-IL-13 treatment have shown some therapeutic promise. Herein, we present evidence that pre- and post-intraperitoneal administration of tacrolimus (FK506) is very effective in reducing CCR3/Siglec-F⁺ eosinophils in Aspergillus-challenged asthma and EoE, CD2-IL-5 induced global eosinophilia, and DOX regulated IL-13-induced asthma. We used flow cytometry and anti-major basic protein (MBP) immunostaining to examine eosinophils in the spleen, bone marrow, BALF, lung, oesophagus and intestine. Additionally, we also performed ELISA and Western blot analyses to show that tacrolimus treatment also reduces the levels of eosinophil-specific cytokines IL-4, IL-5, IL-13 and TGF-β, eosinophil-specific chemokines Eotaxin-1 and Eotaxin-2, and progenitors of target RCAN1 mRNA and protein levels. Additionally, the current investigations also show that the TGF-β-mediated oesophageal and lung fibrosis is also reduced in Aspergillus-challenged, CD2-IL-5 transgenic and DOX-responsive IL-13 mice. Mechanistically, we show that tacrolimus in vitro treatment inhibited bone marrow-derived eosinophil proliferation and viability by promoting eosinophil apoptosis that may be associated with downregulation of RCAN1. Taken together, we provide in vivo and in vitro evidence that tacrolimus ameliorates eosinophil levels and associated pathogenesis in allergen-, IL-5- and IL-13-induced EoE, EG and asthma pathogenesis. Considering tacrolimus side-effects and reactivity to several other drugs, we propose the topical use of tacrolimus for paediatric and low-dose oral for adult patients as a novel therapeutic strategy for the clinical trial to reduce mucosal eosinophilia first in steroid-refractory or elemental diet non-responsive adult EoE, EG and asthma patients.

Current treatments for atopic dermatitis in Japan

The goal of a treatment regimen for atopic dermatitis is to reach and maintain a state where the patient exhibits mild symptoms or an absence of symptoms, and the patient should not experience disturbance during daily activities. The basis of a treatment regimen for atopic dermatitis is topical therapy, and currently there exist topical corticosteroids, tacrolimus and delgocitinib. Using these, proactive therapy is performed as maintenance therapy after remission induction therapy. However, in cases of moderate to severe atopic dermatitis, topical drugs alone cannot induce remission and systemic therapies such as cyclosporin, ultraviolet therapy, and dupilumab should be used in combination. In particular, dupilumab has many advantages such as high efficacy, relatively few adverse reactions, and ease of use in elderly patients with severe atopic dermatitis. In this review, we present a treatment algorithm for atopic dermatitis that emphasizes the importance of maintaining remission after induction of remission, and summarizes the characteristics of current medication therapy for atopic dermatitis in Japan.

3,3'-Diindolylmethane alleviates acute atopic dermatitis by regulating T cell differentiation in a mouse model

Atopic dermatitis is a severe, chronic relapsing inflammatory disease of the skin with family clustering. It is characterized into acute phase, which is dominated by T helper 2-type immune responses, and chronic phase, which is dominated by T helper 1-type immune responses. Studies have shown that 3,3'-diindolylmethane not only has antitumor effects but also can relieve symptoms of inflammatory diseases by inhibiting the nuclear factor-κB signaling pathway and regulating T cell differentiation. To study the effect of 3,3'-diindolylmethane on atopic dermatitis and the underlying mechanism, a mouse model of acute atopic dermatitis was established using 2,4-dinitrofluorobenzene. After intraperitoneal injection of 3,3'-diindolylmethane, skin erythema and edema in mice were significantly alleviated. Furthermore, 3,3'-diindolylmethane reduced immune activation, probably by inhibiting the secretion of thymic stromal lymphopoietin by keratinocytes. 3,3'-Diindolylmethane also promoted the differentiation of regulatory T cells and inhibited the activation of T helper 2 and T helper 17 cells to reduce atopic dermatitis-related immune responses. However, it showed no significant effect on the differentiation of T helper 1 cells. These results indicate that 3,3'-diindolylmethane has a significant inhibitory effect on T helper 2 cells in the acute phase of atopic dermatitis. Our findings may provide not only more insights into the pathological mechanism of AD, but also a new candidate medicine for it.

Regulation of Skin Barrier Function via Competition between AHR Axis versus IL-13/IL-4‒JAK‒STAT6/STAT3 Axis: Pathogenic and Therapeutic Implications in Atopic Dermatitis

Atopic dermatitis (AD) is characterized by skin inflammation, barrier dysfunction, and chronic pruritus. As the anti-interleukin-4 (IL-4) receptor α antibody dupilumab improves all three cardinal features of AD, the type 2 cytokines IL-4 and especially IL-13 have been indicated to have pathogenic significance in AD. Accumulating evidence has shown that the skin barrier function is regulated via competition between the aryl hydrocarbon receptor (AHR) axis (up-regulation of barrier) and the IL-13/IL-4‒JAK‒STAT6/STAT3 axis (down-regulation of barrier). This latter axis also induces oxidative stress, which exacerbates inflammation. Conventional and recently developed agents for treating AD such as steroid, calcineurin inhibitors, cyclosporine, dupilumab, and JAK inhibitors inhibit the IL-13/IL-4‒JAK‒STAT6/STAT3 axis, while older remedies such as coal tar and glyteer are antioxidative AHR agonists. In this article, I summarize the pathogenic and therapeutic implications of the IL-13/IL-4‒JAK‒STAT6/STAT3 axis and the AHR axis in AD.

Tacrolimus ointment in the treatment of hormone-dependent dermatitis: A protocol of systematic review

BACKGROUND

Long-term use of corticosteroid ointment for external using or skin management products and cosmetics containing corticosteroid will produce a hormone-dependent effect on facial skin and destroy the barrier function of the skin. It is easy to cause repeated attacks of facial skin inflammation after drug withdrawal because corticosteroid hormones can cause the expression of inflammatory factors in the body, which has a serious impact on patients. The general treatment method is to stop using hormone drugs for psychotherapy and inform patients of the basic knowledge of hormone-dependent dermatitis and daily facial care, but the effect is not good. At present, non-steroidal ointment tacrolimus (a calcineurin inhibitor) is widely used in the treatment of hormone-dependent dermatitis. Tacrolimus ointment is effective for corticosteroid-dependent dermatitis, but adverse events can also occur.

METHODS

We plan to searched all randomized controlled trials (RCTs) fortacrolimus ointment therapy of hormone-dependent dermatitis in: MEDLINE, PubMed, EMBASE, the Cochrane Central Register of Controlled Trials (CENTRAL), Springer and Web of Science, China Biomedical Literature Database (CBM), China Science Journal Database (VIP database) and Wanfang Database, China National Knowledge Infrastructure (CNKI), without the limitation of publication status and language until September 1, 2020. The systematic review will also search will also search for identify publications, meeting minutes, and grey literature (including unpublished meeting articles).

DISCUSSION

The systematic review mainly to access the safety and efficacy of tacrolimus ointment for hormone-dependent dermatitis (facial corticosteroid addiction dermatitis and facial steroid dermatitis). The results of our research will facilitate evidence-based management of patients with facial corticosteroid-dependent dermatitis and provide clinical advice on their treatment options.

REGISTRATION

PROSPERO CRD42020171813.

Topical tacrolimus with different frequency for exfoliative cheilitis: a pilot study

Background: Tacrolimus is a new type immunosuppressant. The aim of this study was to evaluate the effectiveness of topical tacrolimus 0.1% ointment at 2 different frequencies in treating patients with exfoliative cheilitis.Methods: A total of 40 patients with exfoliative cheilitis were randomly divided into the QD group receiving topical tacrolimus 0.1% ointment once a day or the QOD group receiving topical tacrolimus 0.1% ointment once-two-day. Patients were also applied wet dressing of saline twice a day. The effectiveness of treatment was defined as the percentage of improvement in signs or symptoms.Results: 37 patients completed the 2-week treatment. And, a full set was analyzed. The effectiveness of topical tacrolimus 0.1% ointment for relief in objective sign and subjective symptom was 50% and 67.5%% in the QD group, respectively. For the QOD group, the effectiveness of sign and symptom relief was 50% and 73.5%. There was no significant difference of effectiveness between application topical tacrolimus once a day and once 2 days.Conclusion: Our data suggested that application of topical tacrolimus 0.1% ointment once a day and once 2 days had similar clinical effectiveness for sign and symptom relief in patients with exfoliative cheilitis.

PMMA Safety for Facial Filling: Review of Rates of Granuloma Occurrence and Treatment Methods

PMMA is composed of microspheres suspended in bovine collagen. Once injected in a dermal area, the carrier is absorbed, giving place to collagen that gives volume and maintains the spheres in the place. This process may give origin to exacerbate foreign body reaction and granuloma. The frequency of such complication is not clear. The primary objective was to review and compare the frequencies of granuloma between the published studies. The secondary aim was to compare the therapies and efficacies. The series of cases in which PMMA was used as facial filler were reviewed, and the rate of granulomas was compared; the case report studies describing those complications were also reviewed, and the therapies and outcomes were quantified. The data showed general frequency of PMMA-related complications of 4.9% and granulomas 1.9%; the incidence of granuloma was 1/2075 patients-year, and the time to development ranged from 6 to 180 months. The most used therapies were steroid, surgery or both, with satisfactory results. In conclusion, considering the actual risks and benefits of PMMA, we may affirm that it is a safe filler; doctors and patients must be conscious of potential risks when deciding for its use. LEVEL OF EVIDENCE IV: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266.

Immunomodulatory effects of tacrolimus (FK506) for the treatment of allergic diseases

Tacrolimus has been used to prevent allograft rejection and also used in kidney, liver and heart transplantations. Various preclinical and clinical studies demonstrated that Tacrolimus possess immunomodulatory and anti-inflammatory properties. The mechanism of action of Tacrolimus in allergic diseases involves calcineurin inhibition, and downregulation of T-cell reactivity, IgE degranulation, and its actions on mast cells, dendritic cells, basophils, eosinophils and inhibition of transcription of proinflammatory cytokines. Herein we reviewed the Pharmacotherapeutic mechanism of action of Tacrolimus in the prevention of asthma, atopic dermatitis, and allergic conjunctivitis.

Atopic dermatitis

Atopic dermatitis (AD) is the most common chronic inflammatory skin disease, with a lifetime prevalence of up to 20% and substantial effects on quality of life. AD is characterized by intense itch, recurrent eczematous lesions and a fluctuating course. AD has a strong heritability component and is closely related to and commonly co-occurs with other atopic diseases (such as asthma and allergic rhinitis). Several pathophysiological mechanisms contribute to AD aetiology and clinical manifestations. Impairment of epidermal barrier function, for example, owing to deficiency in the structural protein filaggrin, can promote inflammation and T cell infiltration. The immune response in AD is skewed towards T helper 2 cell-mediated pathways and can in turn favour epidermal barrier disruption. Other contributing factors to AD onset include dysbiosis of the skin microbiota (in particular overgrowth of Staphylococcus aureus), systemic immune responses (including immunoglobulin E (IgE)-mediated sensitization) and neuroinflammation, which is involved in itch. Current treatments for AD include topical moisturizers and anti-inflammatory agents (such as corticosteroids, calcineurin inhibitors and cAMP-specific 3',5'-cyclic phosphodiesterase 4 (PDE4) inhibitors), phototherapy and systemic immunosuppressants. Translational research has fostered the development of targeted small molecules and biologic therapies, especially for moderate-to-severe disease.

Glyteer, Soybean Tar, Impairs IL-4/Stat6 Signaling in Murine Bone Marrow-Derived Dendritic Cells: The Basis of Its Therapeutic Effect on Atopic Dermatitis

Atopic dermatitis (AD) is a common inflammatory skin disease. Recent studies have revealed the involvement of T helper (Th)2 cytokines including Interleukin 4 (IL-4) in the pathogenesis of AD. Since epidermal Langerhans cells (LCs) and dermal myeloid dendritic cells (DCs) produce CCL17 and CCL22 that chemoattract Th2 cells, interfering with CCL17 and CCL22 production from LCs and dermal myeloid DCs may be beneficial in the treatment of AD. To investigate this, we stimulated murine bone marrow-derived DCs (BMDCs) with IL-4. IL-4 stimulation produced Ccl17 and Ccl22, which was attenuated by soybean tar Glyteer, a known aryl hydrocarbon receptor (Ahr) activator. Notably, Glyteer treatment blocked the nuclear translocation of Stat6 induced by IL-4 stimulation, suggesting that this treatment impairs the IL-4/Stat6 signaling pathway in BMDCs. Unexpectedly, Glyteer treatment did not potently upregulate the expression of Cyp1a1, a specific Ahr-responsive gene, suggesting that its inhibitory machinery for Ccl17 and Ccl22 expression is likely to operate in an Ahr-independent manner. These findings indicate that Glyteer may exhibit therapeutic potential for AD by downregulating the CCL17 and CCL22 production from DCs in a Th2-deviated microenvironment.