scholarly journals Skin Barrier Abnormalities and Immune Dysfunction in Atopic Dermatitis

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.

2021 ◽  
Vol 17 (1) ◽  
Author(s):  
Alyssa Sweeney ◽  
Vanitha Sampath ◽  
Kari C. Nadeau

Abstract Background Atopic diseases, such as atopic dermatitis (AD) and food allergy (FA), have increased in prevalence in industrialized countries during the past few decades and pose a significant health burden. They appear to have a common underlying mechanism and a natural disease progression. AD is generally the first atopic disease to manifest followed by other atopic diseases, such as FA, allergic rhinitis, or allergic asthma suggesting that they are likely different manifestations of the same disease. Body Evidence suggests that allergic sensitization occurs through an impaired skin barrier, while consumption of these foods at an early age may actually result in tolerance. This has been termed the Dual-Allergen-Exposure hypothesis. Loss of barrier integrity has been hypothesized to enable penetration of allergens, pollutants, and microbes and initiation of an inflammatory immune cascade of events leading to sensitization. The immune dysfunction is thought to further exacerbate the impaired skin barrier to form a vicious cycle. There is much interest in preventing or protecting the skin barrier from developing a proinflammatory atopic state, which may potentially lead to the development of AD and subsequently, FA. Conclusion Research on preventing or treating skin barrier dysfunction is ongoing. A number of studies have evaluated the efficacy of emollients in preventing AD and FA with mixed results. Studies have differed in the study design, population characteristics, emollients type, and frequency, duration, and area of application. Emollient type has varied widely from oils, creams, petrolatum-based lotions, and trilipid creams. Current research is directed towards the use of trilipid emollients that are similar to the skin’s natural lipid composition with a 3:1:1 ratio of ceramides, cholesterol and free fatty acids and a pH that is similar to that of skin to determine their effectiveness for skin barrier repair and prevention of AD and FA.


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 24 (3) ◽  
pp. 267-272
Author(s):  
Airiss R. Chan ◽  
Vijay K. Sandhu ◽  
Aaron M. Drucker ◽  
Patrick Fleming ◽  
Charles W. Lynde

Atopic dermatitis (AD) is a chronic skin disease characterized by barrier dysfunction and immune dysregulation that affects approximately 20% of children and 2-5% of adults worldwide. Traditionally, AD has been considered a disease of childhood with many cases resolving before adulthood. However, in recent years, the prevalence of adult AD is increasingly recognized to be substantial, but it is uncertain whether this increase is due to increased childhood-persistent or relapsed AD, or new adult-onset AD. This highlights a need for further investigation into the adult AD population and evaluation of phenotypes in the adult-onset cohort. In this literature review, we examine five studies focused on adult-onset AD phenotype, conducted between 2013 and 2017. The most commonly reported body regions affected in adult-onset AD were the hands, eyelids, neck, and flexural surfaces of the upper limbs. These vary from childhood-onset AD findings, which are less specific to body regions other than flexural areas. These findings have implications for diagnostic accuracy and treatment of AD, including considerations for therapeutic choices and inclusion and exclusion criteria in clinical trials.


2021 ◽  
Author(s):  
Liu Tang ◽  
Jiefang Gao ◽  
Xiaoqin Cao ◽  
Lu Chen ◽  
Huiling Wang ◽  
...  

2021 ◽  
Vol 12 ◽  
Author(s):  
Yotaro Nishikawa ◽  
Tomohiro Fukaya ◽  
Takehito Fukui ◽  
Tomofumi Uto ◽  
Hideaki Takagi ◽  
...  

Atopic dermatitis (AD) is a common pruritic inflammatory skin disease characterized by impaired epidermal barrier function and dysregulation of Thelper-2 (TH2)-biased immune responses. While the lineage of conventional dendritic cells (cDCs) are implicated to play decisive roles in T-cell immune responses, their requirement for the development of AD remains elusive. Here, we describe the impact of the constitutive loss of cDCs on the progression of AD-like inflammation by using binary transgenic (Tg) mice that constitutively lacked CD11chi cDCs. Unexpectedly, the congenital deficiency of cDCs not only exacerbates the pathogenesis of AD-like inflammation but also elicits immune abnormalities with the increased composition and function of granulocytes and group 2 innate lymphoid cells (ILC2) as well as B cells possibly mediated through the breakdown of the Fms-related tyrosine kinase 3 ligand (Flt3L)-mediated homeostatic feedback loop. Furthermore, the constitutive loss of cDCs accelerates skin colonization of Staphylococcus aureus (S. aureus), that associated with disease flare. Thus, cDCs maintains immune homeostasis to prevent the occurrence of immune abnormalities to maintain the functional skin barrier for mitigating AD flare.


2020 ◽  
Vol 4 (2) ◽  
pp. 9
Author(s):  
Akihiro Aioi

Peroxisome proliferator-activated receptors (PPARs) are fatty acid activated transcription factors that belong to the nuclear hormone receptor family. They are initially known as transcriptional regulators of lipid and glucose metabolism, although further evidence has also been accumulated for other functions. Due to the nature of all PPAR isotypes which are expressed and exert effects by regulating the functions of cell types residing and infiltrating in the skin, PPARs represent a major research target for the understanding and treatment of many skin diseases. Atopic dermatitis (AD) is a chronic and relapsing disease characterized by skin barrier dysfunction and immune dysregulation. Skin barrier disturbance is one of the exacerbation factors of AD, due to facile penetration of molecules such as antigens. From the aspect of immune dysregulation, innate and acquired immunity including cell proliferation, cell differentiation, and cytokine network are involved in the pathogenesis. In this review, the role of PPAR in AD and the possibility of its agonist for the treatment of AD are discussed.


2019 ◽  
Vol 3 (1) ◽  
Author(s):  
Akihiro Aioi ◽  
Takuhiro Yamada

Perturbation of cutaneous homeostasis including immune dysregulation and skin barrier dysfunction evokes skin disorders. In this study, we examined the effect of Eucalyptus citriodora (Euc-c) extract on cytokine production, cell proliferation and cell differentiation in HaCaT cells to elucidate its influence on cutaneous homeostasis. Euc-c suppressed significantly LPS-induced IL-6 and TNF-a-induced IL-8 production from HaCaT cells. Conversely IL-1ra production was significantly enhanced by Euc-c. The expressions of IVL, CERS3 and CERS4, keratinocyte differentiation markers, were upregulated to 3.1, 2.8 and 2.7-fold respectively by Euc-c treatment, compared to the control, while the proliferation was downregulated. The lipid contents in Euc-c-treated cells tended to increase, compared with non-treated cells. To explore the underlying mechanism of these effect, we next performed siRNA experiments against PPAR-b/d. Euc-c enhanced PPAR-b/d mRNA expression to 3.25-fold, while PPAR-b/d mRNA expression in transfected cells was suppressed. The expressions of IVL, CERS3 and CERS4 in transfected cells were suppressed to 1.48, 0.82 and 0.72-fold respectively, concomitant with suppression of PPAR-b/d mRNA expression. These results indicated that Euc-c exerts anti-inflammatory effects and regulates keratinocyte differentiation via the modulation of PPAR-b/d pathway. Therefore, the application of Euc-c is expected to exert beneficial effect on skin disorders evoked by perturbation of skin homeostasis.Key words: Eucalyptus citriodora, PPAR-b/d, inflammation, barrier function, cutaneous homeostasis


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