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

2021 ◽  
Author(s):  
Liu Tang ◽  
Jiefang Gao ◽  
Xiaoqin Cao ◽  
Lu Chen ◽  
Huiling Wang ◽  
...  
2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Johny Bajgai ◽  
Jing Xingyu ◽  
Ailyn Fadriquela ◽  
Rahima Begum ◽  
Dong Heui Kim ◽  
...  

Abstract Background Atopic dermatitis (AD) is a chronic allergic inflammatory skin disease characterized by complex pathogenesis including skin barrier dysfunction, immune-redox disturbances, and pruritus. Prolonged topical treatment with medications such as corticosteroids, calcineurin inhibitors, and T-cell inhibitors may have some potential side-effects. To this end, many researchers have explored numerous alternative therapies using natural products and mineral compounds with antioxidant or immunomodulatory effects to minimize toxicity and adverse-effects. In the current study, we investigated the effects of mineral complex material (MCM) treatment on 2, 4-dinitrochlorobenzene (DNCB)-induced AD-like skin lesions in SKH-1 hairless mice. Methods Animals were divided into four groups; normal control (NC), negative control treated with DNCB only (DNCB only), positive control treated with DNCB and tacrolimus ointment (PC) and experimental group treated with DNCB and MCM patch (MCM). Skin inflammation and lesion severity were investigated through analyses of skin parameters (barrier score and strength, moisture and trans-epidermal water loss level), histopathology, immunoglobulin E, and cytokines. In addition, reactive oxygen species (ROS), nitric oxide (NO), glutathione peroxidase (GPx), and catalase (CAT) levels were measured in both serum and skin lysate. Results Our results demonstrates that MCM patch improved the progression of AD-like skin lesions by significantly increasing skin barrier strength and decreasing trans-epidermal water loss. Additionally, dermal administration of MCM patch significantly reduced epidermal thickness, ROS, and NO levels in skin lysate. Furthermore, we found that MCM suppressed the levels of AD-involved (Th1 and Th2) cytokines such as IL-2, IFN-γ, and IL-4 in blood. In addition, the levels of other Th1, and Th2 and inflammatory cytokines such as IL-1β, TNF-α, IL-6, IL-12(p70) and IL-10 were found lowest in the MCM group than in the DNCB only and PC groups. Moreover, we found total serum IgE level significantly increased after DNCB treatment, but decreased in the PC and MCM groups. Conclusion Taken together, our findings suggest that MCM application may have beneficial effects either systemic or regional on DNCB-induced AD lesional skin via regulation of the skin barrier function and immune-redox response.


2019 ◽  
Vol 32 (9) ◽  
pp. 606 ◽  
Author(s):  
Tiago Torres ◽  
Eduarda Osório Ferreira ◽  
Margarida Gonçalo ◽  
Pedro Mendes-Bastos ◽  
Manuela Selores ◽  
...  

With an increasing prevalence during the past decades, atopic dermatitis has become a global health issue. A literature search following a targeted approach was undertaken to perform this non-systematic review, which intends to provide an overview of the epidemiology, pathophysiology, clinical features, comorbidities, and current therapies for the treatment of atopic dermatitis. In sum, this is a heterogeneous skin disorder associated with variable morphology, distribution, and disease course. Although not completely understood, its pathogenesis is complex and seems to result from a combination of genetic and environmental factors that induce skin barrier dysfunction, cutaneous and systemic immune dysregulation, skin microbiota dysbiosis, and a strong genetic influence. Diagnosis is based on specific criteria that consider patient and family history and clinical manifestations. Overall disease severity must be determined by evaluating both objective signs and subjective symptoms. Therapeutic goals require a multistep approach, focusing on reducing pruritus and establishing disease control. Patients should be advised on basic skin care and avoidance of triggers. Topical anti-inflammatory agents should be considered in disease flares or chronic/recurrent lesions. In case of inadequate response, phototherapy, systemic immunosuppressants and, more recently, dupilumab, should be added. Nevertheless, the treatment of moderate-to-severe atopic dermatitis remains challenging and novel, efficacious, safe and targeted treatments are urgently needed. In conclusion, although the last few years have seen important improvement in the understanding of the disease, future research in atopic dermatitis will continue exploring gene-environment interactions and how it affects pathophysiology, disease severity, and treatment outcomes.


2020 ◽  
Vol 21 (8) ◽  
pp. 2867 ◽  
Author(s):  
Gabsik Yang ◽  
Jin Kyung Seok ◽  
Han Chang Kang ◽  
Yong-Yeon Cho ◽  
Hye Suk Lee ◽  
...  

Atopic dermatitis (AD) is a common and relapsing skin disease that is characterized by skin barrier dysfunction, inflammation, and chronic pruritus. While AD was previously thought to occur primarily in children, increasing evidence suggests that AD is more common in adults than previously assumed. Accumulating evidence from experimental, genetic, and clinical studies indicates that AD expression is a precondition for the later development of other atopic diseases, such as asthma, food allergies, and allergic rhinitis. Although the exact mechanisms of the disease pathogenesis remain unclear, it is evident that both cutaneous barrier dysfunction and immune dysregulation are critical etiologies of AD pathology. This review explores recent findings on AD and the possible underlying mechanisms involved in its pathogenesis, which is characterized by dysregulation of immunological and skin barrier integrity and function, supporting the idea that AD is a systemic disease. These findings provide further insights for therapeutic developments aiming to repair the skin barrier and decrease inflammation.


2012 ◽  
Vol 2012 ◽  
pp. 1-6 ◽  
Author(s):  
Y. Valdman-Grinshpoun ◽  
D. Ben-Amitai ◽  
A. Zvulunov

Atopic dermatitis is a multifactorial, chronic relapsing, inflammatory disease, characterized by xerosis, eczematous lesions, and pruritus. The latter usually leads to an “itch-scratch” cycle that may compromise the epidermal barrier. Skin barrier abnormalities in atopic dermatitis may result from mutations in the gene encoding for filaggrin, which plays an important role in the formation of cornified cytosol. Barrier abnormalities render the skin more permeable to irritants, allergens, and microorganisms. Treatment of atopic dermatitis must be directed to control the itching, suppress the inflammation, and restore the skin barrier. Emollients, both creams and ointments, improve the barrier function of stratum corneum by providing it with water and lipids. Studies on atopic dermatitis and barrier repair treatment show that adequate lipid replacement therapy reduces the inflammation and restores epidermal function. Efforts directed to develop immunomodulators that interfere with cytokine-induced skin barrier dysfunction, provide a promising strategy for treatment of atopic dermatitis. Moreover, an impressive proliferation of more than 80 clinical studies focusing on topical treatments in atopic dermatitis led to growing expectations for better therapies.


2021 ◽  
Vol 79 (3) ◽  
pp. 207-216
Author(s):  
Tiago Fernandes Gomes ◽  
Rebeca Calado ◽  
Margarida Gonçalo

Impaired skin barrier is one of the hallmarks of atopic dermatitis (AD), with abnormalities in the cornified envelope, lipid lamellae, tight junctions and cutaneous microbiome. These findings are also present in nonlesional skin of AD individuals, suggesting that epidermal barrier defects may be the initial step towards the development of AD and eventually other atopic diseases (atopic march). It is currently known that pathophysiology of AD involves an interplay between this dysfunctional skin barrier and a predominantly type 2 skewed innate and adaptive immune responses, which further disrupt the skin barrier through type 2 cytokines. In this setting, there is enhanced penetration of environmental and food allergens through a deficient barrier, leading to an increased susceptibility to sensitization. During the sensitization process, thymic stromal lymphopoietin (TSLP) polarizes skin dendritic cells to a T-helper 2 response, and TSLP seems to be a key cytokine in the sensitization of food allergy, allergic asthma and rhinitis. In this review, the authors describe the current knowledge of the pathophysiology of the epidermal barrier, its disruption in AD and how it may be involved in the development of atopic comorbidities and the role of barrier repair therapy on the prevention of the atopic march progression.  


2021 ◽  
Author(s):  
◽  
Karmella Naidoo

<p>Atopic dermatitis (AD) is a highly debilitating disease with significant health impacts worldwide. It is a chronic and relapsing inflammatory skin disease which often poses a life-long burden for the affected individuals. AD has been a difficult disease to treat as it manifests with a wide spectrum of clinical phenotypes and the current clinical management strategies are non-specific. Therefore, it is imperative to identify specific immunological pathways that could be targeted to treat this disease. Previous studies have documented that AD disease progression is precipitated by a combination of skin barrier dysfunction, itch and immune dysregulation that are responsible for AD progression. However, the precise role of effector cells and cytokines have not been fully elucidated. To address this, I established a clinically relevant model of AD, using the vitamin D analogue, MC903. This MC903 model closely resembles the AD phenotype in patients, including inflammatory parameters, barrier dysfunction, itch, and histopathological characteristics, providing a novel platform to evaluate targets for the treatment and prevention of AD. Furthermore, this model exposed the cells and cytokines that are critically associated with disease severity, including eosinophils, mast cells, TSLP, IL-4 and IL-9, but not CD4+ T cells. The instrumental role of these effector cells and cytokines was established by their stepwise depletion or blockade. Indeed, functional eosinophil depletion via the use of inducible eosinophil (iPHIL) mice significantly ameliorated AD pathology, most notably itch. Similar results were obtained after blockade of the IL-4/IL-13 axis by genetic deletion of STAT6. The clinically more relevant use of soluble inhibitors targeting IL-9 and CRTh2 (in a prophylactic and therapeutic setting, respectively), both resulted in a substantial reduction in AD phenotype. In summary, this body of work led to the identification of key disease-initiating and effector cells and molecules that represent attractive targets for the treatment of AD.</p>


2021 ◽  
Vol 23 (1) ◽  
pp. 226
Author(s):  
Jin-Su Oh ◽  
Geum-Su Seong ◽  
Yong-Deok Kim ◽  
Se-Young Choung

The prevalence of atopic dermatitis (AD), a disease characterized by severe pruritus, immune imbalance, and skin barrier dysfunction, is rapidly increasing worldwide. Deacetylasperulosidic acid (DAA) has anti-atopic activity in the three main cell types associated with AD: keratinocytes, mast cells, and eosinophils. Our study investigated the anti-atopic activity of DAA in 2,4-dinitrochlorobenzene-induced NC/Nga mice. DAA alleviated the symptoms of AD, including infiltration of inflammatory cells (mast cells and eosinophils), epidermal thickness, ear thickness, and scratching behavior. Furthermore, DAA reduced serum IgE, histamine, and IgG1/IgG2a ratio and modulated the levels of AD-related cytokines and chemokines, namely interleukin (IL)-1β, IL-4, IL-6, IL-9, IL-10, IL-12, tumor necrosis factor-α, interferon-γ, thymic stromal lymphopoietin, thymus and activation-regulated chemokine, macrophage-derived chemokine, and regulated on activation the normal T cell expressed and secreted in the serum. DAA restored immune balance by regulating gene expression and secretion of Th1-, Th2-, Th9-, Th17-, and Th22-mediated inflammatory factors in the dorsal skin and splenocytes and restored skin barrier function by increasing the expression of the pro-filaggrin gene and barrier-related proteins filaggrin, involucrin, and loricrin. These results suggest DAA as a potential therapeutic agent that can alleviate the symptoms of AD by reducing pruritus, modulating immune imbalance, and restoring skin barrier function.


2020 ◽  
Vol 19 (6) ◽  
pp. 432-443
Author(s):  
Nikolay N. Murashkin ◽  
Leyla S. Namazova-Baranova ◽  
Leonid A. Opryatin ◽  
Roman V. Epishev ◽  
Alexander I. Materikin ◽  
...  

Atopic dermatitis (AD) is the disease with chronic inflammation, epidermal barrier dysfunction and microbial dysbiosis. AD is widespread, including pediatric population. The article discusses the disease’s pathogenesis: skin barrier deficiency, immunological causes of chronic inflammation, characteristics of normal skin microbiome and its disorders on both affected and unaffected skin of children with AD. Main principles of systemic treatment for moderate and severe forms of disease are considered. Features of targeted therapy with dupilumab (IL 4/IL 13 inhibitor) in children with moderate and severe forms of AD are discussed. The overview of the research results on the dupilumab efficacy and safety is presented.


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