Animal models for atopic dermatitis: are they relevant to human disease?

Topically Applied Therapies for the Treatment of Skin Disease: Past, Present, and Future

The purpose of this review is to summarize essential biological, pharmaceutical, and clinical aspects in the field of topically applied medicines that may help scientists when trying to develop new topical medicines. After a brief history of topical drug delivery, a review of the structure and function of the skin and routes of drug absorption and their limitations is provided. The most prevalent diseases and current topical treatment approaches are then detailed, the organization of which reflects the key disease categories of autoimmune and inflammatory diseases, microbial infections, skin cancers, and genetic skin diseases. The complexity of topical product development through to large-scale manufacturing along with recommended risk mitigation approaches are then highlighted. As such topical treatments are applied externally, patient preferences along with the challenges they invoke are then described, and finally the future of this field of drug delivery is discussed, with an emphasis on areas that are more likely to yield significant improvements over the topical medicines in current use or would expand the range of medicines and diseases treatable by this route of administration. SIGNIFICANCE STATEMENT: This review of the key aspects of the skin and its associated diseases and current treatments along with the intricacies of topical formulation development should be helpful in making judicious decisions about the development of new or improved topical medicines. These aspects include the choices of the active ingredients, formulations, the target patient population's preferences, limitations, and the future with regard to new skin diseases and topical medicine approaches.

Exogenous drug-induced mouse models of atopic dermatitis

Atopic dermatitis (AD) is an inflammatory skin disease characterized by intense pruritus. AD is harmful to both children and adults, but its pathogenic mechanism has yet to be fully elucidated. The development of mouse models for AD has greatly contributed to its study and treatment. Among these models, the exogenous drug-induced mouse model has shown promising results and significant advantages. Until now, a large amount of AD-related research has utilized exogenous drug-induced mouse models, leading to notable advancements in research. This indicates the crucial significance of applying such models in AD research. These models exhibit diverse characteristics and are highly complex. They involve the use of various strains of mice, diverse types of inducers, and different modeling effects. However, there is currently a lack of comprehensive comparative studies on exogenous drug-induced AD mouse models, which hinders researchers' ability to choose among these models. This paper provides a comprehensive review of the features and mechanisms associated with various exogenous drug-induced mouse models, including the important role of each cytokine in AD development. It aims to assist researchers in quickly understanding models and selecting the most suitable one for further investigation.

Phyllostachys nigra Munro var alleviates inflammatory chemokine expression and DNCB-induced atopic-like dermatitis in BALB/c mice

ETHNOPHARMACOLOGICAL RELEVANCE

Phyllostachys nigra (PN) is an herbal medicine that originates from the inner bark of Phyllostachys nigra Munro var. henosis Stapf or Phyllostachys bambusoides Siebold et Zuccarini. It has long been used to relieve fever and to treat diarrhea and inflammation. PN has been shown to possess inhibitory effects on pneumonia, intestinal inflammation, tumors, and fatigue. However, its potential efficacy in the treatment of atopic dermatitis (AD) has not been extensively studied or reported.

AIM OF THE STUDY

The objective of this research was to investigate the impact of PN on HaCaT and HMC-1 cells, as well as its potential in an experimental model of AD induced by 1-chloro-2,4-dinitrobenzene (DNCB).

METHODS

We analyzed the anti-inflammatory efficacy of PN in HaCaT cells and HMC-1 cells using ELISA and PCR, and investigated invasion of inflammatory cell, change of dermis and epidermis, and the SCORAD index in AD-like mice model. We also measured the MAPK signaling pathway using the dorsal tissue of mice.

RESULTS

Our results show that PN reduced the expressions of TARC, GM-CSF, TNF-α, MCP-1, and IL-6 in vitro. PN also decreased the SCORAD index, thickening of epidermis and dermis, and inhibited the invasions of mast cells and eosinophils as well as CD4+ T and CD8+ T cells. Furthermore, PN suppressed the level of IgE and IL-6, and also inhibited the MAPK phosphorylation in the dorsal skin.

CONCLUSION

These results demonstrate that PN could be an effective alternative medicine for allergic inflammatory disease.

Cymbaria daurica L.: A Mongolian herbal medicine for treating eczema via natural killer cell-mediated cytotoxicity pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Cymbaria daurica L. (C. daurica) is a perennial herb known commonly as "Xinba" (Chinese) and "Kanba-Arong" (Mongolian). In Mongolia, it is used as a traditional medicine to treat eczema and other skin diseases due to its anti-swelling, anti-inflammatory, anti-hemorrhagic, and anti-itching properties. However, the potential mechanism of action for eczema treatment has not been reported.

AIM OF THE STUDY

To investigate the effect of C. daurica on 1-chloro-2,4-dinitrobenzene (DNCB)-induced eczema in rats and the associated action mechanism.

MATERIALS AND METHODS

Qualitative analysis of C. daurica was performed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Based on information obtained from compound identification and relevant literature, the possible targets of C. daurica against eczema were analyzed using network pharmacology and molecular docking methods. The DNCB-induced eczema rat models were treated with different dosages of C. daurica extract (10, 50, and 250 mg/mL per day), and the therapeutic effects subsequently evaluated based on the degree of skin inflammation, spleen index, and hematoxylin and eosin staining (H&E staining). Enzyme-linked immunosorbent assay (ELISA), reverse transcription quantitative polymerase chain reaction (RT-qPCR), and western blotting were used to analyze the relevant target effects. The C. daurica mechanism of action on eczema was verified by animal experiments. High-performance liquid chromatography (HPLC) was carried out to determine the content of active ingredients in C. daurica. In addition, the physicochemical properties of the extract were evaluated.

RESULTS

Our analysis of the 173 targets included in the protein-protein interaction (PPI) network identified tumor necrosis factor (TNF) and interleukin 2 (IL-2) as key targets involved in the treatment of eczema with C. daurica extract. Furthermore, the 173 targets were associated with the natural killer cell-mediated cytotoxicity pathway. Our results showed that C. daurica significantly reduced IL-2 and TNF-α serum levels in eczema rat models (P < 0.0001); thus, playing an important role in the anti-inflammatory response. Furthermore, according to the p-value, RT-qPCR and western blotting showed that the expression of Src homology 2 domain-containing protein tyrosine phosphatase 1 (SHP-1), Vav guanine nucleotide exchange factor (Vav), and growth factor receptor-bound protein 2 (Grb2) changed in the skin of the eczema model rats after treatment with the C. daurica extract.

CONCLUSION

Our study confirms that C. daurica can inhibit SHP-1, Vav, and Grb2 expression; thereby, inhibiting the natural killer cell-mediated cytotoxicity pathway. These results provide insight into the mechanism of C. daurica in treating eczema.

Integrative transcriptome-wide analysis of atopic dermatitis for drug repositioning

Atopic dermatitis (AD) is one of the most common inflammatory skin diseases, which significantly impact the quality of life. Transcriptome-wide association study (TWAS) was conducted to estimate both transcriptomic and genomic features of AD and detected significant associations between 31 expression quantitative loci and 25 genes. Our results replicated well-known genetic markers for AD, as well as 4 novel associated genes. Next, transcriptome meta-analysis was conducted with 5 studies retrieved from public databases and identified 5 additional novel susceptibility genes for AD. Applying the connectivity map to the results from TWAS and meta-analysis, robustly enriched perturbations were identified and their chemical or functional properties were analyzed. Here, we report the first research on integrative approaches for an AD, combining TWAS and transcriptome meta-analysis. Together, our findings could provide a comprehensive understanding of the pathophysiologic mechanisms of AD and suggest potential drug candidates as alternative treatment options.

Integrative genomic and transcriptomic analyses on publicly available data-sets together with in silico drug repositioning identifies alternative therapeutic options to treat atopic dermatitis.

Management of Atopic Dermatitis Via Oral and Topical Administration of Herbs in Murine Model: A Systematic Review

Over the past few decades, complementary and alternative medicine (CAM) using herbs, or their active constituents have garnered substantial attention in the management of a chronic and relapsing inflammatory skin disorder called atopic dermatitis (AD), particularly in attenuating disease recurrence and maintaining long-term remission. In Eastern Asian countries including China, Korea and Taiwan, herbal medicine available in both topical and oral preparation plays a significant role in treating skin diseases like AD as they possibly confer high anti-inflammatory properties and immunomodulatory functions. Conventional murine models of AD have been employed in drug discovery to provide scientific evidence for conclusive and specific pharmacological effects elicited by the use of traditional herbs and their active constituents. Coupled with the goal to develop safe and effective novel therapeutic agents for AD, this systematic review consists of a summary of 103 articles on both orally and topically administered herbs and their active constituents in the murine model, whereby articles were screened and selected via a specialized framework known as PICO (Population, Intervention, Comparator and Outcome). The objectives of this review paper were to identify the efficacy of oral and topical administered herbs along with their active constituents in alleviating AD and the underlying mechanism of actions, as well as the animal models and choice of inducer agents used in these studies. The main outcome on the efficacy of the majority of the herbs and their active constituents illustrated suppression of Th2 response as well as improvements in the severity of AD lesions, suppression of Immunoglobulin E (IgE) concentration and mast cell infiltration. The majority of these studies used BALB/c mice followed by NC/Nga mice (commonly used gender-male; commonly used age group - 6-8 weeks). The most used agent in inducing AD was 2, 4-Dinitrochlorobenzene (DNCB), and the average induction period for both oral and topical administered herbs and their active constituents in AD experiments lasted between 3 and 4 weeks. In light of these findings, this review paper could potentially assist researchers in exploring the potential candidate herbs and their active constituents using murine model for the amelioration of AD.

Accelerating topical formulation development for inflammatory dermatoses; an ex vivo human skin culture model consistent with clinical therapeutics

Although animal models have been extensively used to evaluate human topical therapeutics, they exhibit marked physiological differences to human skin. Our objective was to develop a human ex vivo skin culture model to explore the pathophysiology of inflammatory dermatoses and for preclinical testing of potential therapeutic treatments. Ex vivo skin barrier integrity and metabolic activity was retained for 5 days and stimulation of T-helper cells (Th1), which produce proinflammatory cytokines, provided inflammatory responses similar to those reported from in vivo biopsy. Tissue responses to established therapies of pimecrolimus (Elidel) and clobetasol propionate (Dermovate) were evaluated using the human ex vivo skin culture, assessing pharmacodynamic changes in gene expression alongside the pharmacokinetics of drug penetration with both products showing time dependent efficacies. The translational utility of the human ex vivo skin culture model of inflammatory dermatoses was demonstrated through comparison with an in vivo clinical study, with similar reductions in inflammatory gene expression recorded for both drug treatments. Thus, this model can reduce, replace or refine animal testing and also mitigate the risk of failure in costly and time-consuming clinical trials associated with novel topical therapeutic development.

Satellite Glial Cells and Neurons in Trigeminal Ganglia Are Altered in an Itch Model in Mice

Itch (pruritus) is a common chronic condition with a lifetime prevalence of over 20%. The mechanisms underlying itch are poorly understood, and its therapy is difficult. There is recent evidence that following nerve injury or inflammation, intercellular communications in sensory ganglia are augmented, which may lead to abnormal neuronal activity, and hence to pain, but there is no information whether such changes take place in an itch model. We studied changes in neurons and satellite glial cells (SGCs) in trigeminal ganglia in an itch model in mice using repeated applications of 2,4,6-trinitro-1-chlorobenzene (TNCB) to the external ear over a period of 11 days. Treated mice showed augmented scratching behavior as compared with controls during the application period and for several days afterwards. Immunostaining for the activation marker glial fibrillary acidic protein in SGCs was greater by about 35% after TNCB application, and gap junction-mediated coupling between neurons increased from about 2% to 13%. The injection of gap junction blockers reduced scratching behavior, suggesting that gap junctions contribute to itch. Calcium imaging studies showed increased responses of SGCs to the pain (and presumed itch) mediator ATP. We conclude that changes in both neurons and SGCs in sensory ganglia may play a role in itch.

1-Iodohexadecane Alleviates 2,4-Dinitrochlorobenzene-Induced Atopic Dermatitis in Mice: Possible Involvements of the Skin Barrier and Mast Cell SNARE Proteins

Atopic dermatitis (AD) is a chronic inflammatory dermal disease with symptoms that include inflammation, itching, and dry skin. 1-Iodohexadecane is known as a component of Chrysanthemum boreale essential oil that has an inhibitory effect on AD-like lesions. However, its effects on AD-related pathological events have not been investigated. Here, we explored the effects of 1-iodohexadecane on AD lesion-related in vitro and in vivo responses and the mechanism involved using human keratinocytes (HaCaT cells), mast cells (RBL-2H3 cells), and a 2,4-dinitrochlorobenzene (DNCB)-induced mouse model (male BALB/c) of AD. Protein analyses were performed by immunoblotting or immunohistochemistry. In RBL-2H3 cells, 1-iodohexadecane inhibited immunoglobulin E-induced releases of histamine and β-hexosaminidase and the expression of VAMP8 protein (vesicle-associated membrane proteins 8; a soluble N-ethylmaleimide-sensitive factor attachment protein receptor [SNARE] protein). In HaCaT cells, 1-iodohexadecane enhanced filaggrin and loricrin expressions; in DNCB-treated mice, it improved AD-like skin lesions, reduced epidermal thickness, mast cell infiltration, and increased filaggrin and loricrin expressions (skin barrier proteins). In addition, 1-iodohexadecane reduced the β-hexosaminidase level in the serum of DNCB-applied mice. These results suggest that 1-iodohexadecane may ameliorate AD lesion severity by disrupting SNARE protein-linked degranulation and/or by enhancing the expressions of skin barrier-related proteins, and that 1-iodohexadecane has therapeutic potential for the treatment of AD.

A new ex vivo skin model for mechanistic understanding of putative anti-inflammatory topical therapeutics

Several in vitro models have been designed as test systems for inflammatory skin conditions, commonly using cell-culture or reconstructed human epidermis approaches. However, these systems poorly recapitulate the physiology and, importantly, the metabolism and biochemical activity of skin in vivo, whereas ex vivo skin culture models can retain these features of the tissue. Our objective was to develop a human ex vivo skin culture model to explore the pathophysiology of inflammatory dermatoses and for preclinical testing of potential therapeutic treatments. Following exogenous stimulation, tissue integrity and ability to induce inflammatory gene expression was retained, and stimulant concentrations and duration was optimised to mimic published data from inflammatory clinical biopsies of dermatitis and psoriasis patients. The validity and utility of the model was demonstrated when challenged with 5 drugs including a corticosteroid and vitamin D3 analogue, where inflammatory biomarkers were regulated in a manner consistent with the drugs' reported in vivo mechanisms of action. This model retains important inflammatory gene signals observed in human inflammatory dermatoses for preclinical evaluation of novel therapeutics.

Study on the Molecular Basis of Huanglian Jiedu Decoction Against Atopic Dermatitis Integrating Chemistry, Biochemistry, and Metabolomics Strategies

Atopic dermatitis (AD) is a common chronic relapsing skin inflammation, which severely affect the quality of life of patients. Inhibiting itching and enhancing immunity to mitigate scratching are key elements in the fight against AD. Huanglian Jiedu decoction (HLJDD) has multiple pharmacological effects in the treatment of AD. However, the effective ingredients and underlying molecular mechanisms have not yet been fully explored. Thus, this study integrates chemistry, biochemistry, and metabolomics strategies to evaluate the active substance basis of HLJDD against AD. First, HLJDD was split to five fractions (CPF, 40AEF, 90AEF, PEF and WEF) and 72 chemical components were identified. NSD (Non-similarity degree) among the different fractions showed significant chemical differences (>81%). Interleukin IL-13, IL-17A, IL-3, IL-31, IL-33, IL4, IL-5, TSLP, IgE, and histamine in the serum, and IL-4Rα, JAK1, and HRH4 levels in skin, participating in inhibiting itching and regulating immunity signaling, were found to be restored to varying degrees in AD treating with HLJDD and its fractions, especially 40AEF and CPF. Untargeted metabolomics analysis demonstrated that forty metabolites were differential metabolites in plasma between the HLJDD-treated group and the AD group, involving in histidine metabolism, arginine biosynthesis, pyrimidine metabolism, and so on. Further, targeted metabolomics analysis revealed that eleven differential metabolites, associating with physiological and biochemical indices, were significant improved in the HLJDD and its fractions groups. In conclusion, HLJDD exhibited anti-AD effects by inhibiting itching and enhancing immunity, which in turn regulating the levels of relative metabolites, and CPF and 40AEF were considered the most important components of HLJDD.

A Comprehensive Review of Therapeutic Approaches Available for the Treatment of Dermatitis

BACKGROUND

Dermatitis or eczema is a prevalent skin disorder worldwide and is also very common as a pediatric inflammatory skin disorder. Its succession gets worse with the multiple comorbidities which exhibit mechanisms that are poorly understood. Its management further becomes a challenge due to the limited effective treatment options available. However, the Novel Drug Delivery Systems (NDDS) along with new targeting strategies can easily bypass the issues associated with dermatitis management. If we compare the active constituents against phytoconstituents effective against dermatitis then phytoconstituents can be perceived to be more safe and gentle.

OBJECTIVE

Administration of NDDS of plant extract or actives displays improved absorption behavior, which helps them to permeate through lipid-rich biological membrane leading to increased bioavailability. The newer efficient discoveries related to eczema can face various exploitations. This can be intervened by the subjection of patent rights, which not only safeguard the novel works of individual(s) but also give them the opportunity to share details of their inventions with people globally.

CONCLUSION

The present review focuses on the available research about the use of nanoformulations in the topical delivery. It further elaborates the use of different animal models as the basis to characterize the different features of dermatitis. The review also highlights the recent nanoformulations which have the ability to amplify the delivery of active agents through their incorporation in transfersomes, ethosomes, niosomes or phytosomes, etc.

Effects of chloroform fraction of Fritillariae Thunbergii Bulbus on atopic symptoms in a DNCB-induced atopic dermatitis-like skin lesion model and in vitro models

ETHNOPHARMACOLOGICAL RELEVANCE

Fritillariae thunbergii Bulbus (FT), knowns as "Jeolpaemo ()" in Korean traditional medicine, is a perennial plant belonging to the Liliaceae family and has been used to treat symptoms such as cough, sputum formation, and purulent pneumonia. Owing to its effects of lowering heat, removing sputum, and reducing swelling, the plant has also been used as an external prescription medicine to treat inflammation.

AIM OF THE STUDY

To analyze the anti-inflammatory effects of FT-ethanol extract (FT-Et) and FT-chloroform fraction extract (FT-Cl) on 1-chloro-2,4-dinitrobenzene (DNCB)-induced atopic dermatitis (AD) in vivo and in vitro.

MATERIALS AND METHODS

The effect of FT-Et and FT-Cl on AD was observed using an AD-like skin lesion model induced by DNCB in vivo. HaCaT and RBL2H3 cells were used to determine the effects of FT-Et and FT-Cl in vitro. After inducing AD-like skin lesions in vivo, FT was topically applied to the skin lesion for 35 days. Epidermal thickness, dermal thickness, scratching behavior, infiltration of inflammatory cells, and expression of skin barrier proteins were measured. TARC, MDC, and IL-4 levels were analyzed using ELISA in HaCaT cells. Beta-hexosaminidase and IL-4 levels were measured in RBL2H3 cells. The expression of filaggrin (FLG), loricrin (LOR), involucrin (INV), and aquaporin-3(AQP-3) was measured by PCR. Phosphorylation of MAPKs was analyzed using Western blot technique.

RESULTS

FT-Cl significantly reduced ear swelling, scratching behavior, SCORAD index, epidermal thickness, infiltration of inflammatory cells, and loss of skin barrier proteins. FT-Et inhibited the infiltration of mast cells and CD8⁺ cells and decreased the loss of skin barrier proteins. In TNF-α/IFN-γ-stimulated HaCaT cells, FT-Cl inhibited TRAC, MDC, and IL-4 expression and upregulated the expression of FLG, INV, and AQP-3, whereas FT-Et inhibited the expression of TRAC and MDC and increased the expression of FLG, INV, and AQP-3 at high concentrations. In RBL2H3, FT-Cl downregulated β-hexosaminidase and IL-4 expression. In addition, FT-Cl inhibited the phosphorylation of ERK and p-38 in HaCaT and RBL2H3 cells.

CONCLUSIONS

Collectively, FT-Cl showed better effect than FT-Et in vivo and in vitro. These results suggest that a specific component present in FT-Cl acted against AD. Future research should focus on the analysis of components contained in FT-Cl and the anti-inflammatory effects of the active ingredient.

A TCM formula VYAC ameliorates DNCB-induced atopic dermatitis via blocking mast cell degranulation and suppressing NF-κB pathway

ETHNOPHARMACOLOGICAL RELEVANCE

A Traditional Chinese Medicine (TCM) formula (VYAC) consists of three herbs including Viola yedoensis Makino, herb (Violaceae, Viola), Sophora flavescens Aiton, root (Fabaceae, Sophora) and Dictamnus dasycarpus Turcz, root and rhizome (Rutaceae, Dictamnus), has been traditionally prescribed to treat various skin diseases in clinic.

AIM OF THE STUDY

This study aims to investigate the therapeutic effects of VYAC on the 2,4-dinitrobenzene (DNCB) induced atopic dermatitis (AD)-like mice and to explore the underlying mechanisms.

MATERIALS AND METHODS

VYAC was extracted with 70 % aqueous ethanol and lyophilized powder was used. AD-like mice were challenged by DNCB, VYAC (150 and 300 mg/kg) were oral administration daily from day 7 to day 28. At the end of experiment, the clinical scores were recorded, serum and skin in the dorsal were isolated to evaluate the therapeutic effects of VYAC. RBL-2H3 cells were stimulated with C48/80 for degranulation and plasmids expressing constitutively active form of Syk (Silence or overexpression) were transfected into RBL-2H3 cells to explore the underlying mechanisms in vitro.

RESULTS

VYAC significantly ameliorated the cardinal symptoms in the DNCB-induced AD-like mice by repairing the skin barrier function, inhibiting mast cells infiltration, restraining the serum IgE and histamine release and decreasing TNF-α, IL-4 as well as Syk mRNA level in dorsal skin and alleviating inflammation. Besides, VYAC significantly blocked RBL-2H3 cells degranulation, reduced β-hexosaminidase and histamine release, and suppressed NF-κB pathway. What's more, the degranulation of RBL-2H3 was reduced after Syk silence and increased after Syk overexpression.

CONCLUSION

Our findings clearly suggested that VYAC treat AD through inhibiting the inflammatory mediator productions and blocking mast cell degranulation via suppressing Syk mediated NF-κB pathway.

Vaccinia Virus Expressing Interferon Regulatory Factor 3 Induces Higher Protective Immune Responses against Lethal Poxvirus Challenge in Atopic Organism

Vaccinia virus (VACV) is an enveloped DNA virus from the Orthopoxvirus family, various strains of which were used in the successful eradication campaign against smallpox. Both original and newer VACV-based replicating vaccines reveal a risk of serious complications in atopic individuals. VACV encodes various factors interfering with host immune responses at multiple levels. In atopic skin, the production of type I interferon is compromised, while VACV specifically inhibits the phosphorylation of the Interferon Regulatory Factor 3 (IRF-3) and expression of interferons. To overcome this block, we generated a recombinant VACV-expressing murine IRF-3 (WR-IRF3) and characterized its effects on virus growth, cytokine expression and apoptosis in tissue cultures and in spontaneously atopic Nc/Nga and control Balb/c mice. Further, we explored the induction of protective immune responses against a lethal dose of wild-type WR, the surrogate of smallpox. We demonstrate that the overexpression of IRF-3 by WR-IRF3 increases the expression of type I interferon, modulates the expression of several cytokines and induces superior protective immune responses against a lethal poxvirus challenge in both Nc/Nga and Balb/c mice. Additionally, the results may be informative for design of other virus-based vaccines or for therapy of different viral infections.

Cicadidae Periostracum Attenuates Atopic Dermatitis Symptoms and Pathology via the Regulation of NLRP3 Inflammasome Activation

Atopic dermatitis (AD) is a multifactorial inflammatory skin disease of complex etiology. Despite its increasing prevalence, treatment for AD is still limited. Crude drugs, including herbal extracts or natural resources, are being used to treat AD symptoms, with minimum side effects. Cicadidae Periostracum (CP), derived from the slough of insects belonging to the family Cicadidae, is a commonly used crude drug in traditional Asian medicine to treat/control epilepsy, shock, and edema. However, the effect of CP on AD-like skin lesions is unknown. In this study, we examined the effect of a CP water extract on AD disease development in vivo, using a house dust mite-induced AD mouse model, and in vitro, using HaCaT keratinocytes and a 3D human skin equivalent system. Importantly, CP administration alleviated house dust mite-induced AD-like symptoms, suggested by the quantified dermatitis scores, animal scratching behaviors, skin moisture retention capacity, and skin lesion and ear thickness. Furthermore, histopathological analysis demonstrated that CP decreased intralesional mast cell infiltration. In addition, CP treatments decreased the systemic levels of immunoglobulin E, histamine, and thymic stromal lymphopoietin (TSLP) and the local mRNA expression of TSLP and several Th1/Th2 cytokines. Our data suggest that these effects were mediated by the inhibition of nucleotide-binding oligomerization domain-like receptor protein 3 (NLRP3) inflammasome activation. In vivo and in vitro CP treatments resulted in the downregulation of inflammasome components, such as ASC and cleaved caspase-1, as well as related mediators such as IL-1β and reactive oxygen species. Collectively, our results suggest that CP is a potential therapeutic agent for AD, controlling inflammatory responses through the suppression of NLRP3 inflammasome activation.

Adipose-derived stem cells attenuate atopic dermatitis-like skin lesions in NC/Nga mice

There is an unmet need in novel therapeutics for atopic dermatitis (AD). We examined the effects of autologous adipose-derived stem cells (ADSCs) on AD-like skin lesions induced by the application of 2,4-dinitrochlorobenzene (DNCB) in NC/Nga mice. Autologous ADSCs and ADSC-conditioned medium (ADSC-CM) were injected intralesionally three times. Clinical severity and histopathologic findings were compared in sham naïve control, saline-treated, ADSC-treated, ADSC-CM-treated and 2.5% cortisone lotion-applied animals. The severity index, skin thickness, mast cell number, as well as expression levels of thymic stromal lymphopoietin, CD45, chemoattractant receptor-homologous molecule, chemokine ligand 9 and chemokine ligand 20 were significantly lower in mice treated with ADSC, ADSC-CM, or 2.5% cortisone lotion. Tissue levels of interferon-γ as well as serum levels of interleukin-33 and immunoglobulin E levels were also decreased in those groups. We conclude that autologous ADSCs improved DNCB-induced AD-like skin lesions in NC/Nga mice by reducing inflammation associated with Th2 immune response and interferon-γ.

Pseudoephedrine alleviates atopic dermatitis-like inflammatory responses in vivo and in vitro

AIMS

Atopic dermatitis is a chronic inflammatory disease characterized by eczematous lesions and has become a serious health problem worldwide. Pseudoephedrine (PSE) is a nasal decongestant to treat the common cold. PSE has been reported that is beneficial to allergic diseases. However, whether PSE has the potential in atopic dermatitis remains to be elucidated.

MAIN METHODS

Male BALB/c mice were challenged with 2,4-dinitrochlorobenzene (DNCB) to induce atopic dermatitis-like lesion and orally administrated with PSE for two weeks. The skin hydration and the scratching behavior were detected. The skin lesions and histopathological changes were evaluated and inflammatory factors levels were detected. Human Keratinocytes (HaCaT cells) were stimulated by TNF-α/IFN-γ after PSE-pretreatment. The transcriptions of inflammatory factors were detected.

KEY FINDINGS

PSE decreased skin lesion area and skin thickness in atopic dermatitis mice. PSE improved skin hydration and scratching. Histologically, PSE reduced mast cell and CD4+ cell infiltration. PSE suppressed serum TNF-α and IgE levels, reducing cytokines (IL-1β, IL-4, IL-6, IL-13, IL-33, TSLP, and IL-23) and neutrophil migration factors (CCL2 and MMP-9) in skin tissues. In addition, PSE inhibited TNF-α/IFN-γ-induced release of inflammatory factors (TNF-α, IL-1β, and IL-23) in HaCaT cells. Furthermore, PSE suppressed the activation of MAPKs and NF-κB signaling pathways in vivo and in vitro.

SIGNIFICANCE

These results demonstrate that PSE could inhibit inflammatory responses in atopic dermatitis models. PSE may serve as a viable alternatives drug for the treatment of atopic dermatitis.

Physiology and Pathophysiology of Itch

Itch is a topic to which everyone can relate. The physiological roles of itch are increasingly understood and appreciated. The pathophysiological consequences of itch impact quality of life as much as pain. These dynamics have led to increasingly deep dives into the mechanisms that underlie and contribute to the sensation of itch. When the prior review on the physiology of itching was published in this journal in 1941, itch was a black box of interest to a small number of neuroscientists and dermatologists. Itch is now appreciated as a complex and colorful Rubik's cube. Acute and chronic itch are being carefully scratched apart and reassembled by puzzle solvers across the biomedical spectrum. New mediators are being identified. Mechanisms blur boundaries of the circuitry that blend neuroscience and immunology. Measures involve psychophysics and behavioral psychology. The efforts associated with these approaches are positively impacting the care of itchy patients. There is now the potential to markedly alleviate chronic itch, a condition that does not end life, but often ruins it. We review the itch field and provide a current understanding of the pathophysiology of itch. Itch is a disease, not only a symptom of disease.

A Natural Compound Mixture Containing Arctigenin, Hederagenin, and Baicalein Alleviates Atopic Dermatitis in Mice by Regulating HPA Axis and Immune Activity

Forsythiae Fructus, Lonicerae Flos, and Scutellariae Radix are medicinal herbs that possess anti-inflammatory and anti-atopic effects. Hence, we investigated the effects of a mixture (ADM), containing arctigenin, hederagenin, and baicalein, which are the main compound from these herbs on atopic dermatitis (AD) skin lesions and the underlying molecular mechanisms. ADM was topically applied to dorsal skin lesions of 2,4-dinitrochlorobenzene- (DNCB-) induced ICR mice, and the expressions of proinflammatory mediators and HPA axis hormones were investigated. The topical application of 0.5% ADM significantly reduced the DNCB-induced symptoms of AD in ICR mice. Histological analysis showed that ADM exerted antiatopic effects by reducing the epidermal thickness and mast cell infiltration into skin lesions. 0.5% ADM attenuated the levels of TNF-α, IFN-γ, IL-4, and VEGF in skin lesions and serum IgE. The production of Th1-/Th2-related cytokines in splenic tissues, including TNF-α, IFN-γ, IL-12, and IL-4, were also decreased by ADM treatment. ADM diminished corticotropin-releasing hormone (CRH), adrenocorticotropic hormone (ACTH), and corticosteroid (CORT) production in DNCB-induced mice. In vitro, ADM reduced the productions of TARC/CCL17, MDC/CCL22, IL-6, and ICAM-1 in TNF-α/IFN-γ- (TI-) stimulated HaCaT cells by suppressing the ERK and JNK signaling pathways. In addition, ADM inhibited corticotropin-releasing hormone/substance P- (CRH/SP-) induced VEGF production in HMC-1 cells. These results suggest that ADM may have therapeutic potential in AD by reducing inflammation and attenuating HPA axis activation.

Preventive effects of a novel herbal mixture on atopic dermatitis-like skin lesions in BALB/C mice

BACKGROUND

A combination of parts of Cornus officinalis, Rosa multiflora, Lespedeza bicolor, Platycladus orientalis, and Castanea crenata is commonly used for alleviating inflammatory skin disorders. Therefore, this study was carried out to evaluate the in vitro and in vivo preventive effects of a novel herbal formula made from the five plants (C2RLP) against atopic dermatitis in BALB/C mice.

METHODS

Mice were allocated into five groups (n = 8) including, control (Normal, petrolatum, and betamethasone treated) and treatment groups (treated with 2.5 and 5% C2RLP ointment). Atopic lesion was induced by applying 1-Chloro-2, 4-dinitrobenzene to the dorsal thoracic area of mice. Macroscopical and histological evaluations were performed to determine the effects of treatment on the progress of the skin lesions. The effects of treatment on the production and release of interleukins, interferon -ϒ, nitrite, prostaglandin E2, thymus and activation-receptor chemokine, and β-hexosaminidase were evaluated and comparisons were made between groups. In addition, the chemical compounds present in C2RLP were identified by Liquid Chromatography-Mass Spectrometry.

RESULTS

Topical application of C2RLP reduced the dermatitis score and suppressed histopathological changes in mice. Treatment significantly reduced (P < 0.05) plasma IL-4 level, the production of nitrite, prostaglandin E2, and thymus and activation-receptor chemokine production. The lipopolysaccharide-induced iNOS-mRNA expression in RAW 264.7 cells was also suppressed by high concentrations of C2RLP. In addition, C2RLP showed an inhibitory effect against DPPH free radical (IC50 = 147.5 μg/ml) and β-hexosaminidase release (IC50 = 179.5 μg/ml). Liquid Chromatography-Mass Spectrometry analysis revealed the presence of various compounds, including loganin, ellagic acid, and kaempferol 3-glucoside.

CONCLUSION

Down-regulation of T- helper 2 cellular responses and suppression of inflammatory mediators contributed to the protective effects of C2RLP from atopic dermatitis in BALB/C mice.

Topical administration of EGF suppresses immune response and protects skin barrier in DNCB-induced atopic dermatitis in NC/Nga mice

Atopic dermatitis (AD) is a common inflammatory skin disease characterized by a complex, heterogeneous pathogenesis including skin barrier dysfunction, immunology, and pruritus. Although epidermal growth factor (EGF) is essential for epithelial homeostasis and wound healing, the effect of EGF on AD remains to be explored. To develop a new therapy for AD, the anti-AD potential of EGF was investigated by inducing AD-like skin lesions in NC/Nga mice using 2,4-dinitrochlorobenzene (DNCB). EGF was administrated to NC/Nga mice to evaluate its therapeutic effect on DNCB-induced AD. EGF treatment improved dermatitis score, ear thickness, epidermal hyperplasia, serum total immunoglobulin E level, and transepidermal water loss in NC/Nga mice with DNCB-induced AD. In addition, levels of skin barrier-related proteins such as filaggrin, involucrin, loricrin, occludin, and zonula occludens-1 (ZO-1) were increased by EGF treatment. These beneficial effects of EGF on AD may be mediated by EGF regulation of Th1/Th2-mediated cytokines, mast cell hyperplasia, and protease activated receptor-2 (PAR-2) and thymic stromal lymphopoietin (TSLP), which are triggers of AD. Taken together, our findings suggest that EGF may potentially protect against AD lesional skin via regulation of skin barrier function and immune response.

Non-invasive bioluminescence imaging as a standardized assessment measure in mouse models of dermal inflammation

BACKGROUND

Myeloperoxidase is used as a marker and diagnostic tool for inflammatory processes. Hypochlorous acid produced by myeloperoxidase oxidizes luminol to produce light. By injecting luminol into experimental animals, inflammatory processes can be tracked in real-time by bioluminescence imaging (BLI).

OBJECTIVE

We aimed to establish BLI as a standardized assessment measure in three mouse models of dermal inflammation.

METHODS

Oxazolone-induced delayed-type-hypersensitivity (DTH) (acute), a model for dermatitis, imiquimod (IMQ) (sub-chronic) model for psoriasis and the (chronic) bleomycin model for scleroderma were used. In the first two models, dexamethasone and clobetasol, respectively, were used as reference compounds. In all cases, classical readouts such as dermal swelling, severity scores and histological analyses were compared with in- vivo bioluminescence.

RESULTS

In DTH, bioluminescence peaked earlier than ear swelling, reflecting early cell infiltration. Dexamethasone blocked both ear swelling and bioluminescence. In the IMQ model, bioluminescence closely reflected the psoriasis scores and histology and revealed a relapse-remitting course of the disease. Clobetasol partially decreased the disease severity. After stopping IMQ and clobetasol treatment, BLI adopted a rhythmic pattern during resolution. Bleomycin induced an increase in bioluminescence and in collagen thickness. BLI revealed a time-course of the effects of bleomycin that was not reflected by histology alone.

CONCLUSION

For drug discovery and translational purposes, it is important that disease processes be tracked in vivo and possibly over a long period. We conclude that BLI is a valuable and reliable method for in-vivo measurement of dermal inflammation and potentially for inflammation resolution.

A novel mouse model of atopic dermatitis that is T helper 2 (Th2)-polarized by an epicutaneous allergen

The pathogenesis of atopic dermatitis (AD) involves T helper 2 (Th2) cells, and effective therapies remain elusive due to the paucity of animal models. We aimed to develop a mouse model of an immune system aberration caused by allergen. Experiments were conducted in two phases. In experiment 1, BALB/c mice were sensitized with one of four chemical allergens - toluene diisocyanate (TDI), hexamethylene diisocyanate (HDI), trimellitic anhydride (TMA), or 2,4-dinitrochlorobenzene (DNCB) - for 3 weeks. Based on results of experiment 1, immunological features were compared between TMA-sensitized BALB/c mice and NC/Nga mice, after exposure to mite extracts, harmful chemicals and detergents in experiment 2. Sensitization by allergen caused a large number of pathological changes in the skin, and an increase in mast cell number. TMA-sensitized BALB/c mice models showed higher sensitivity to an environmental allergen than NC/Nga mice did. Overall, the initial sensitization with TMA leads to disturbances in Th2-mediated immunity.

Alternatives to animal testing in basic and preclinical research of atopic dermatitis

Atopic dermatitis (AD) is a chronic inflammatory skin disease of increasing prevalence, especially in industrialized countries. Roughly 25% of the children and 1%-3% of adults are affected. Although significant progress has been made in the understanding of the pathogenesis of AD, many aspects remain poorly understood. Moreover, there is a pressing need for improved therapeutic options. Studies to elucidate the pathophysiological pathways of AD and to identify novel therapeutic targets over the last few decades have been conducted almost exclusively in animal models. However, in vitro approaches such as 3D skin disease models have recently emerged due to an increasing awareness of distinct interspecies-related differences that hamper the effective translation of results from animal models to humans. In addition, there is growing political and social pressure to develop alternatives to animal models according to the 3Rs principle (reduction, refinement and replacement of animal models).

Protective Effect of Botulinum Toxin Type A Against Atopic Dermatitis-Like Skin Lesions in NC/Nga Mice

BACKGROUND

Botulinum neurotoxin (BTX) A possesses various biological activities, including anti-inflammatory and antipruritic actions. Human and animal studies have shown that BTX is effective in treating histamine-induced itch, lichen simplex chronicus, psoriasis, rosacea, allergic rhinitis, and scar prevention. However, its effect on atopic dermatitis (AD) has not been studied yet.

OBJECTIVE

To examine the effect of BTX on AD using a mouse model. The primary outcome was skin thickness and transepidermal water loss (TEWL), and the secondary outcome was the alteration in skin severity scores, histological, and laboratory test results.

METHODS

Forty-two NC/Nga mice (a mouse model for AD) were allocated into 6 groups (the untreated, 2-Chloro-1,3,5-trinitrobenzene [TNCB] alone, TNCB + BTX 30 U/kg, TNCB + BTX 60 U/kg, TNCB + vehicle [0.9% saline], TNCB + 0.03% tacrolimus). Those of the BTX group received intradermal injections of BTX on the rostral back once on the day of TNCB sensitization. The effect of BTX in TNCB-treated NC/Nga mice was assessed by measuring skin thickness, TEWL (primary outcome), the skin severity scores, histological changes of test skin including mast cell count, interleukin (IL)-4 mRNA and protein expression, and total serum IgE (secondary outcome).

RESULTS

A single intradermal injection of BTX significantly suppressed skin thickness and TEWL in the TNCB-applied skin. The clinical severity scores, acanthosis and mast cell infiltration, were less in the BTX groups. BTX injection also inhibited TNCB-induced increase in IL-4 mRNA and protein expression in mice, but its effect on serum IgE level was not significant.

CONCLUSION

The preliminary results suggest that BTX may be a novel approach to the prevention and supplemental treatment of acute AD lesions.

Pseudolaric acid B attenuates atopic dermatitis-like skin lesions by inhibiting interleukin-17-induced inflammation

Pseudolaric acid B (PB), isolated from the extract of the root bark of Pseudolarix kaempferi Gordon, has been used as a traditional remedy for the treatment of skin diseases. However, the information of PB on atopic dermatitis (AD) remains largely unknown. In the present study, oral administration with PB improved the severity scores of AD-like skin lesions dose-dependently in NC/Nga mice through reducing serum IgE, pro-inflammatory cytokines, and the infiltration of inflammatory cells. In addition, PB significantly attenuated the levels of IL-17 and IL-22, and the proportion of Th17 cells in NC/Nga mice, as well as decreased IL-17-induced inflammation in RAW264.7 cells. Moreover, PB inhibited the phosphorylation of IκBα and miR-155 expression both in NC/Nga mice and in IL-17-stimulated RAW264.7 cells, which could be reversed by GW9662, a specific antagonist for PPARγ. The incorporation of GW9662 reversed the inhibitory effect of PB on the RORγ-mediated activation of the Il17 promoter. Transfection with PPARγ luciferase reporter gene further demonstrated the enhancement of PB on PPARγ transactivation. These findings indicate that PB could ameliorate AD-like skin lesions by inhibiting IL-17-induced inflammation in a PPARγ-dependent manner, which would provide experimental evidence of PB for the therapeutic potential on AD and other inflammatory skin diseases.

The role of toll-like receptor 3 in chronic contact hypersensitivity induced by repeated elicitation

BACKGROUND

Accumulating evidence suggests that Toll-like receptor (TLR)-3 signaling is involved in non-infectious immune and inflammatory reactions as well as in viral infections. The skin of patients with atopic dermatitis (AD) is often infected with virus and bacteria, leading to the aggravation of atopic symptoms. These findings suggest TLR3 signaling may be involved in the pathogenesis of AD, but the exact role of TLR3 in AD remains to be defined.

OBJECTIVE

The purpose of this study was to investigate the role of TLR3 in chronic contact hypersensitivity reactions induced by repeated elicitation, resembling the features of AD.

METHODS

Wild-type (WT) and Toll-like receptor 3 knockout (Tlr3 KO) mice were sensitized, and chronic contact hypersensitivity reactions were elicited in their ear skin via repeated application of a hapten, 2,4,6-trinitro-1-chlorobenzene (TNCB) or oxazolone.

RESULTS

The Tlr3 KO mice exhibited less ear swelling, less leukocyte infiltration into the skin, and lower serum total IgE levels than WT mice after hapten challenge. The Tlr3 KO mice also displayed lower expression levels of inflammatory cytokines (interleukin (IL)-33, IL-4, IL-10, and interferon-ɤ in their TNCB-treated ear skin than WT mice.

CONCLUSION

These results showed that TLR3 deficiency suppressed the development of chronic contact hypersensitivity reactions, suggesting that TLR3 signaling may participate in the pathogenesis of AD.

Therapeutic application of human leukocyte antigen-G1 improves atopic dermatitis-like skin lesions in mice

Human leukocyte antigen (HLA)-G is an immune checkpoint molecule that plays critical roles in immune response and in triggering inhibitory signaling to immune cells such as T cells, natural killer cells, and antigen-presenting cells. Thus, the application of HLA-G can be considered for treating immune response-related inflammatory disorders. We have previously reported that treatment with HLA-G1 and HLA-G2 ameliorates the joint swelling associated with collagen-induced arthritis of DBA/1 mice, an animal model for rheumatoid arthritis. In this study, we further investigated the effects of HLA-G1 on atopic dermatitis (AD), the most common inflammatory skin disorder. AD-like lesions were induced with the extract of the house dust mite Dermatophagoides farinae in NC/Nga mice. Continuous administration of HLA-G1 ameliorated the AD-like skin lesions in the mice. Furthermore, production of immunoglobulin E, interleukin (IL)-13, and IL-17A was significantly reduced in HLA-G1-treated mice, suggesting a Th2/Th17-mediated immune-inhibitory function of HLA-G1 in vivo. Our studies shed light on novel therapeutic strategies with recombinant HLA-G proteins for immune reaction-mediated chronic inflammatory disorders.

Glycomacropeptide Attenuates Inflammation, Pruritus, and Th2 Response Associated with Atopic Dermatitis Induced by 2,4-Dinitrochlorobenzene in Rat

Atopic dermatitis (AD) is one of the most common skin diseases, whose incidence is increasing in industrialized countries. The epicutaneous application of a hapten, such as 2,4-dinitrochlorobenzene (DNCB), evokes an experimental murine AD-like reaction. Glycomacropeptide (GMP) is a dairy bioactive peptide derived from hydrolysis of κ-casein by chymosin action. It has anti-inflammatory, prebiotic, and immunomodulatory effects. The present study was aimed to investigate the effect of GMP administration on DNCB-induced AD in rats. The severity of inflammatory process, pruritus, production of cytokines, and total immunoglobulin E (IgE) content were measured, and the histopathological features were analyzed. GMP reduced the intensity of inflammatory process and edema of DNCB-induced dermatitis, with a significant decrease in eosinophils recruitment and mast cells hyperplasia. In addition GMP suppressed the serum levels of total IgE and IL-4, IL-5, and IL-13 expression in AD-lesions. Besides, the levels of IL-10 were significantly increased. Remarkably, GMP administration before AD-induction abolished pruritus in dermatitis-like reactions in the rats. Taken together, these results indicate that GMP has an inhibitory effect on AD by downregulating Th2 dominant immune response, suggesting GMP as a potential effective alternative therapy for the prevention and management of AD.

Effects of Hovenia dulcis Thunb. extract and methyl vanillate on atopic dermatitis-like skin lesions and TNF-α/IFN-γ-induced chemokines production in HaCaT cells

OBJECTIVES

Here, we hypothesized that Hovenia dulcis branch extract (HDB) and its active constituents ameliorates 2,4-dinitrochlorobenzene-induced atopic dermatitis (AD)-like skin lesions by modulating the T helper Th1/Th2 balance in NC/Nga mice and TNF-α- and IFN-γ-induced production of thymus and activation-regulated chemokine (TARC) and macrophage-derived chemokine (MDC) in HaCaT cells.

METHODS

HaCaT cells were stimulated by TNF-α/IFN-γ in the presence of HDB and its constituents. TARC and MDC were measured by ELISA and RT-PCR. For the in-vivo study, oral feeding of HDB was performed for 5 weeks with 2,4-dinitrochlorobenzene (DNCB) treatment every other day. The efficacy of HDB on parameters of DNCB-induced AD was evaluated morphologically, physiologically and immunologically.

KEY FINDINGS

In-vitro studies showed that HDB and its constituents suppressed TNF-α/IFN-γ-induced production of TARC and MDC in HaCaT cells by inhibiting MAPK signalling. In-vivo studies showed that HDB regulated immunoglobulin (Ig) E and immunoglobulin G2a (IgG2a) levels in serum and the expression of mRNA for Th1- and Th2-related mediators in skin lesions. Histopathological analyses revealed reduced epidermal thickness and reduced infiltration of skin lesions by inflammatory cells.

CONCLUSION

These results suggest that HDB inhibits AD-like skin diseases by regulating Th1 and Th2 responses in NC/Nga mice and in HaCaT cells.

Forsythia suspensa fruit extracts and the constituent matairesinol confer anti-allergic effects in an allergic dermatitis mouse model

ETHNOPHARMACOLOGICAL RELEVANCE

Forsythia suspensa is used in traditional medicine to treat inflammation. To clarify the anti-inflammatory and anti-allergic effects of F. suspensa fruits, we determined the therapeutic effects of crude extract, fractions, and a constituent from F. suspensa fruits on a murine atopic dermatitis (AD) model.

MATERIALS AND METHODS

We investigated the inhibitory effects of F. suspensa extract (FSE), extract fractions, and the constituent matairesinol on histamine release from MC/9 mast cells activated by compound 48/80 and the development of AD-like skin lesions and symptoms in NC/Nga mice exposed to Dermatophagoides farinae (mite) extract. High performance liquid chromatography (HPLC) analysis of FSE and its fractions were evaluated using matairesinol standard.

RESULTS

FSE, FSE methylene chloride fraction (FSE-MC), and FSE water fraction (FSE-water) inhibited compound 48/80-induced histamine release from MC/9 mast cells. Topical application of FSE or FSE-MC to NC/Nga mice exposed to Dermatophagoides farinae suppressed the development of AD-like skin lesions. Quantitative HPLC analysis of FSE and FSE-MC identified the presence of matairesinol. Topical application of matairesinol to NC/Nga mice effectively reduced AD symptoms, inhibited inflammatory cell infiltration, and lowered immunoglobulin E levels in serum. Further study demonstrated that DfE-induced changes in IL-4 and IFN-γ mRNA expression in the ears of NC/Nga mice were reversed by matairesinol application.

CONCLUSIONS

These results indicate that the F. suspensa and its constituent matairesinol might be a therapeutic candidate for treating allergic inflammatory disorders such as AD.

Chitin nanofibrils suppress skin inflammation in atopic dermatitis-like skin lesions in NC/Nga mice

We evaluated the effect of chitin nanofibril (CNF) application via skin swabs on an experimental atopic dermatitis (AD) model. AD scores were lower, and hypertrophy and hyperkeratosis of the epidermis were suppressed after CNF treatment. Furthermore, inflammatory cell infiltration in both the epidermis and dermis was inhibited. CNFs also attenuated histological scores. The suppressive effects of CNFs were equal to those of corticosteroid application; however, chitin did not show these effects. CNF application might have anti-infllammatory effects via suppression of the activation of nuclear factor-kappa B, cyclooxygenase-2, and inducible nitric oxide synthase. In an early-stage model of experimental AD, CNFs suppressed AD progression to the same extent as corticosteroids. They also suppressed skin inflammation and IgE serum levels. Our findings indicate that CNF application could aid in the prevention or treatment of AD skin lesions.

A Herbal Formula, Atofreellage, Ameliorates Atopic Dermatitis-Like Skin Lesions in an NC/Nga Mouse Model

We evaluated the anti-atopic dermatitis (AD) effect of Atofreellage (AF), a herbal formula composed of 10 medicinal plants. AD was induced on the dorsal skin areas of NC/Nga mice (male, seven weeks old) by daily application of 2,4-dinitrochlorobenzene (DNCB) for five weeks. After three weeks of DNCB application, 200 μL of AF (0, 25, 50 or 100 mg/mL) was applied to the skin lesions. Histological findings, blood cell populations, serum levels of immunoglobulin E (IgE), histamine, pro-inflammatory cytokines, and inflammatory signaling in the skin tissue, and T-helper cell type 2 (Th₂)-related cytokines in splenocytes were analyzed. Histopathological findings showed AF treatment notably attenuated the thickness of dorsal skin, and eosinophil infiltration. AF treatment (especially 100 mg/mL) also demonstrably ameliorated the blood cell population abnormalities, as the notable elevation of serum concentrations of IgE, histamine, TNF-α, IL-6 and IL-1β were remarkably normalized by AF treatment. Western blot analysis evidenced the apparent normalization of inflammatory signals (ERK, p38 MAP kinase, JNK, and NF-κB) in the skin tissue. Additionally, AF treatment notably attenuated the activation of Th₂-dominant cytokines (IL-13, IL-4, and IL-5) in Con A-treated splenocytes in an ex vivo assay. In conclusion, this study provides experimental evidence for the clinical relevance of Atofreellage.

What is the discrepancy between drug permeation into/across intact and diseased skins? Atopic dermatitis as a model

The discrepancy in drug absorption between healthy and diseased skins is an issue that needs to be elucidated. The present study attempted to explore the percutaneous absorption of drugs via lesional skin by using atopic dermatitis (AD) as a model. Tape-stripping and ovalbumin (OVA) sensitization induced AD-like skin. The lesions were evaluated by physiological parameters, histology, cytokines, and differentiation proteins. The permeants of tacrolimus, 8-methoxypsoralen, methotrexate, and dextran were used to examine in vitro and in vivo cutaneous permeation. Transepidermal water loss (TEWL) increased from 5.2 to 27.4 g/m(2)/h by OVA treatment. AD-like lesions were characterized by hyperplasia, skin redness, desquamation, and infiltration of inflammatory cells. Repeated OVA challenge produced a T-helper 2 (Th2) hypersensitivity accompanied by downregulation of filaggrin, involucrin, and integrin β. Tacrolimus, the most lipophilic permeant, revealed an increase of cutaneous deposition by 2.7-fold in AD-like skin compared to intact skin. The transdermal flux of methotrexate and dextran, the hydrophilic permeants, across AD-like skin increased about 18 times compared to the control skin. Surprisingly, AD-like skin showed less skin deposition of 8-methoxypsoralen than intact skin. This may be because the deficient lipids in the atopic-affected stratum corneum (SC) diminished drug partitioning into the superficial skin layer. The fluorescence and confocal microscopic images demonstrated a broad and deep passage of small-molecular and macromolecular dyes into AD-like skin. The results obtained from this report were advantageous for showing how the lesional skin influenced percutaneous absorption.

Pathogenic Actions of Cell Adhesion Molecule 1 in Pulmonary Emphysema and Atopic Dermatitis

Cell adhesion mediated by adhesion molecules is of central importance in the maintenance of tissue homeostasis. Therefore, altered expression of adhesion molecules leads to the development of various tissue disorders involving cell activation, degeneration, and apoptosis. Nevertheless, it still remains unclear what initiates the altered expression of adhesion molecules and how the subsequent pathological cascades proceed. In this regard, cell adhesion molecule 1 (CADM1) is one of the candidates that is involved in the development of pathological lesions; it is an intercellular adhesion molecule that is expressed in various types of cells such as pulmonary cells, neurons, and mast cells. Recent studies have revealed that alterations in the transcriptional or post-transcriptional expressions of CADM1 correlate with the pathogenesis of pulmonary diseases and allergic diseases. In this review, we specifically focus on how CADM1 is involved in the development of pathological lesions in pulmonary emphysema and atopic dermatitis.

Development of eczema vaccinatum in atopic mouse models and efficacy of MVA vaccination against lethal poxviral infection

Smallpox vaccine based on live, replicating vaccinia virus (VACV) is associated with several potentially serious and deadly complications. Consequently, a new generation of vaccine based on non-replicating Modified vaccinia virus Ankara (MVA) has been under clinical development. MVA seems to induce good immune responses in blood tests, but it is impossible to test its efficacy in vivo in human. One of the serious complications of the replicating vaccine is eczema vaccinatum (EV) occurring in individuals with atopic dermatitis (AD), thus excluding them from all preventive vaccination schemes. In this study, we first characterized and compared development of eczema vaccinatum in different mouse strains. Nc/Nga, Balb/c and C57Bl/6J mice were epicutaneously sensitized with ovalbumin (OVA) or saline control to induce signs of atopic dermatitis and subsequently trans-dermally (t.d.) immunized with VACV strain Western Reserve (WR). Large primary lesions occurred in both mock- and OVA-sensitized Nc/Nga mice, while they remained small in Balb/c and C57Bl/6J mice. Satellite lesions developed in both mock- and OVA-sensitized Nc/Nga and in OVA-sensitized Balb/c mice with the rate 40–50%. Presence of mastocytes and eosinophils was the highest in Nc/Nga mice. Consequently, we have chosen Nc/Nga mice as a model of AD/EV and tested efficacy of MVA and Dryvax vaccinations against a lethal intra-nasal (i.n.) challenge with WR, the surrogate of smallpox. Inoculation of MVA intra-muscularly (i.m.) or t.d. resulted in no lesions, while inoculation of Dryvax t.d. yielded large primary and many satellite lesions similar to WR. Eighty three and 92% of mice vaccinated with a single dose of MVA i.m. or t.d., respectively, survived a lethal i.n. challenge with WR without any serious illness, while all Dryvax-vaccinated animals survived. This is the first formal prove of protective immunity against a lethal poxvirus challenge induced by vaccination with MVA in an atopic organism.

Ribes fasciculatum var. chinense Attenuated Allergic Inflammation In Vivo and In Vitro

Ribes fasciculatum var. chinense MAX. (R. fasciculatum) has traditionally been used in Korea to treat inflammatory diseases. However, the exact mechanism that accounts for the anti-inflammatory effect of R. fasciculatum is not completely understood. We aimed to ascertain the pharmacological effects of R. fasciculatum on both compound 48/80- or histamine-induced scratching behaviors and 2, 4-dinitrochlorobenzene (DNCB)-induced atopic dermatitis (AD) in mice. Additionally, to find a possible explanation for the anti-inflammatory effects of R. fasciculatum, we evaluated the effects of R. fasciculatum on the production of inflammatory mediators in LPS-stimulated macrophage cells. Treatment of R. fasciculatum significantly reduced compound 48/80- or histamine-induced the pruritus in mice. R. fasciculatum attenuated the AD symptoms such as eczematous, erythema and dryness and serum IgE levels in AD model. Additionally, R. fasciculatum inhibited the production of tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6). The maximal rates of TNF-α and IL-6 inhibition by R. fasciculatum (1 mg/ml) were approximately 32.12% and 46.24%, respectively. We also showed that R. fasciculatum inhibited the activation of nuclear factor-kappa B in LPS-stimulated macrophages. Collectively, the findings of this study provide us with novel insights into the pharmacological actions of R. fasciculatum as a potential molecule for use in the treatment of allergic inflammatory diseases.

Time-dependent progression from the acute to chronic phases in atopic dermatitis induced by epicutaneous allergen stimulation in NC/Nga mice

Atopic dermatitis (AD) is a complicated skin condition influenced by genetic background and environmental factors. In this study, we applied Dermatophagoides farinae body extract (DfE) to the barrier-disrupted skin of NC/Nga mice twice a week for 8 weeks to identify the clinical and immunological factors in AD progression. Repeated application of the DfE to the skin of NC/Nga mice showed the similar consequences for the natural course of progression in human AD, histologically and immunologically. We confirmed that the AD-like skin lesions in NC/Nga mice did not last for the whole period of our experiment in spite of repeated topical applications of DfE twice a week. Topical DfE stimulation increased the skin mRNA expressions of Th1-, Th2- and Th17-related cytokines in the acute phase. The expression patterns of IL-4 and IL-13 in splenic T cells and skin lesions were consistent with the time course alterations of clinical features of AD-like skin symptoms. We also showed that there was a remission phase either just before or right after the chronic phase in this experimental model. Interestingly, splenic T-cell-derived IL-5 expression began to increase in the chronic phase, while skin-derived IL-5 mRNA expression increased in the acute phase. In conclusion, our results suggest that we should pay attention to the characteristics of each stage of AD progression and choose a suitable corresponding stage of animal model not only to elucidate the pathogenesis of AD but also to develop and evaluate therapeutic drugs for AD.