Atopic dermatitis as a systemic disease

Korean red ginseng water extract alleviates atopic dermatitis-like inflammatory responses by negative regulation of mitogen-activated protein kinase signaling pathway in vivo

Atopic dermatitis (AD) is a chronic inflammatory skin disease. Korean red ginseng is a Korean traditional medicine. In this study, we estimated the effects of Korean red ginseng water extract (RGE) in the 1-chloro-2,4-dinitrobenzene (DNCB)-induced BALB/c mouse model which develops AD-like lesions. After RGE administration (100, 200, and 400 mg/kg) to DNCB-induced mice there were improvements in the dermatitis score and skin pH, a decrease in trans-epidermal water loss, and improved skin hydration. RGE also significantly inhibited eosinophil infiltration, increased filaggrin protein levels, and decreased serum IgE levels, epidermal thickness, mast cell infiltration, and ceramidase release. Compared with that in DNCB-induced mice, RGE effectively decreased the mRNA expression levels of interleukin-6 (IL-6), thymic stromal lymphopoietin (TSLP), and tumor necrosis factor-α (TNF-α), as well as the protein level of thymus and activation-regulated chemokine (TARC). These inhibitory RGE effects are mediated by inhibiting the phosphorylation of mitogen-activated protein kinases (MAPKs), including extracellular signal-regulated kinase (ERK), c-Jun N-terminal kinase (JNK), and p38 MAPK. Furthermore, we confirmed that RGE suppresses interferon-γ (IFN-γ) and TNF-α-induced expression of macrophage-derived chemokine (MDC) and TARC genes in human keratinocyte (HaCaT) cells. Taken together, these results demonstrate that RGE may exert anti-atopic related to responses by suppression the expression of inflammatory mediators, cytokines, and chemokines via downregulation of MAPK signaling pathways, suggesting that RGE may be an effective therapeutic approach for prevention of AD-like disease.

Filaggrin and atopic march

There is an increasing number of experimental, genetic and clinical evidence of atopic dermatitis expression as a pre-condition for later development of other atopic diseases such as asthma, food allergy and allergic rhinitis. Atopic dermatitis is a heterogeneous, recurrent childhood disease, also present in the adult age. It is increasingly attributed to systemic features and is characterized by immunological and skin barrier integrity and function dysregulation. To maintain the protective function of the skin barrier, in particular the maintenance of pH, hydration and antimicrobial functions, the filaggrin, among others, plays a significant role. Filaggrin is a multifunctional, histidine-rich, insoluble protein. The lack of filaggrin is associated with various cutaneous (e.g. ichthyosis vulgaris, allergic contact dermatitis) and non-cutaneous (e.g. diabetes, inflammatory conditions of the gastrointestinal tract) diseases and may be a result of genetic, immunological factors combined with environmental factors. In this review we summarised (emphasized) recent findings in understanding the role of filaggrin in atopic dermatitis and other diseases, participants in the atopic march.

A clinical model for identifying an inflammatory phenotype in mood disorders

Increasingly, clinical research has found inflammatory correlates of psychiatric disorders, particularly mood symptomatology. Biological measures may provide greater precision in many cases and may capture clinically-relevant inflammatory signposts, such as central obesity risk, inflammation-associated co-morbid medical conditions, or proinflammatory lifestyle choices. In order to expand understanding of the role of inflammation in mood disorders, we propose a more inclusive clinical model for capturing an inflammatory phenotype of depression by identifying clinically-relevant inflammatory phenotypes grounded in biology. Our model includes chronic conditions and lifestyle behaviors associated with clinically elevated inflammation in mood disorders. Elements of this "inflamed depression" model include: obesity, low HDL concentrations, elevated triglyceride concentrations, chronically elevated blood pressure, clinical diagnosis of hypothyroidism, migraines, rheumatoid arthritis, adult onset diabetes, inflammatory bowel diseases, inflammatory skin conditions, and lifestyle factors including smoking cigarettes and chronic stress.

Topical Spilanthol Inhibits MAPK Signaling and Ameliorates Allergic Inflammation in DNCB-Induced Atopic Dermatitis in Mice

Atopic dermatitis (AD) is a recurrent allergic skin disease caused by genetic and environmental factors. Patients with AD may experience immune imbalance, increased levels of mast cells, immunoglobulin (Ig) E and pro-inflammatory factors (Cyclooxygenase, COX-2 and inducible NO synthase, iNOS). While spilanthol (SP) has anti-inflammatory and analgesic activities, its effect on AD remains to be explored. To develop a new means of SP, inflammation-related symptoms of AD were alleviated, and 2,4-dinitrochlorobenzene (DNCB) was used to induce AD-like skin lesions in BALB/c mice. Histopathological analysis was used to examine mast cells and eosinophils infiltration in AD-like skin lesions. The levels of IgE, IgG1 and IgG2a were measured by enzyme-linked immunosorbent assay (ELISA) kits. Western blot was used for analysis of the mitogen-activated protein kinase (MAPK) pathways and COX-2 and iNOS protein expression. Topical SP treatment reduced serum IgE and IgG2a levels and suppressed COX-2 and iNOS expression via blocked mitogen-activated protein kinase (MAPK) pathways in DNCB-induced AD-like lesions. Histopathological examination revealed that SP reduced epidermal thickness and collagen accumulation and inhibited mast cells and eosinophils infiltration into the AD-like lesions skin. These results indicate that SP may protect against AD skin lesions through inhibited MAPK signaling pathways and may diminish the infiltration of inflammatory cells to block allergic inflammation.

Anti-Atopic Dermatitis Effect of Seaweed Fulvescens Extract via Inhibiting the STAT1 Pathway

Seaweed fulvescens (SF) is a green alga rich in chlorophyll with unique flavor and taste. It is also called Maesaengi which has antioxidant and other physiological activities. In the present study, we evaluated the therapeutic effects of SF in a mouse model of Dermatophagoides farinae body-induced atopic dermatitis (AD) and in tumor necrosis factor-α and interferon-γ-stimulated HaCaT keratinocytes. SF treatment (200 mg/mouse) inhibited the development of AD symptoms, compared to that in the control group, as evidenced from the improved dorsal skin lesion, reduced thickness and infiltration of inflammatory cells and smaller lymph nodes, and reduced levels of proinflammatory cytokines. In HaCaT keratinocytes, SF (10, 25, and 50 μg/mL) suppressed the production of proinflammatory cytokines in a dose-dependent manner. In addition, SF reduced the phosphorylation of signal transducer and activator of transcription 1, which is one of the major signaling molecules involved in cellular inflammation. These results suggested that SF could be a potential therapeutic alternative for the treatment of AD.

Effect of cinnamamides on atopic dermatitis through regulation of IL-4 in CD4+ cells

This study aimed to evaluate the effects of cinnamamides on atopic dermatitis (AD) and the mechanisms underlying these effects. To this end, the actions of two cinnamamides, (E)-3-(4-hydroxyphenyl)-N-phenylethyl acrylamide (NCT) and N-trans-coumaroyltyramine (NCPA), were determined on AD by orally administering them to mice. Oral administration of the cinnamamides ameliorated the increase in epidermal and dermal thickness as well as mast cell infiltration. Cinnamamides suppressed serum immunoglobulin (Ig) levels and expression of T-helper (Th)1/Th2 cytokines. Moreover, cinnamamides suppressed interleukin (IL)-4, which plays a crucial role in preparing naïve clusters of differentiation (CD)4⁺ T cells, and decreased the cervical lymph node size and weight. Interestingly, in almost all cases, NCPA exhibited higher anti-AD activity compared to NCT. These results strongly indicate that NCPA may have potential as an anti-AD agent, and further mechanistic comparative studies of NCT and NCPA are required to determine the cause of differences in biological activity.

A practical algorithm for topical treatment of atopic dermatitis in the Middle East emphasizing the importance of sensitive skin areas

Background There is a need for safe, effective treatment for atopic dermatitis (AD) in the Middle East. Objective To propose a practical algorithm for the treatment of AD throughout the Middle East. Methods An international panel of six experts from the Middle East and one from Europe developed the algorithm. The practical treatment guide was based on a review of published guidelines on AD, an evaluation of relevant literature published up to August 2016 and local treatment practices. Results Patients with an acute mild-to-moderate disease flare on sensitive body areas should apply the topical calcineurin inhibitor (TCI), pimecrolimus 1% cream twice daily until clearance. For other body locations, a TCI, either pimecrolimus 1% cream, tacrolimus 0.03% ointment in children or 0.1% ointment in adults, should be applied twice daily until clearance. Emollients should be used as needed. Patients experiencing acute severe disease flares should apply a topical corticosteroid (TCS) according to their label for a few days to reduce inflammation. After clinical improvement, pimecrolimus for sensitive skin areas or TCIs for other body locations should be used until there is a complete resolution of lesions. Conclusions These recommendations are expected to optimize AD management in patients across the Middle East.

Ameliorative effects of Juniperus rigida fruit on oxazolone- and 2,4-dinitrochlorobenzene-induced atopic dermatitis in mice

ETHNOPHARMACOLOGICAL RELEVANCE

The fruits of Juniperus rigida have been used in Korean traditional medicine for the treatment of inflammatory diseases in humans such as rheumatoid arthritis.

AIM OF THE STUDY

This study aimed to investigate the anti-atopic properties of J. rigida fruit in in vivo murine atopic dermatitis (AD) models.

METHODS AND RESULTS

BALB/c mouse ears ad SKH-1 hairless mice stimulated with oxazolone (4 weeks) and DNCB (3 weeks), respectively, were treated with the 1% Juniperus rigida fruit EtOH extract (JFE). The JFE improved AD symptoms in both oxazolone- and DNCB-induced AD mice by accelerating skin barrier recovery function and suppressing the overproduction of serum immunoglobulin E (IgE) and interleukin 4 (IL-4). The JFE was found to contain isoscutellarein-7-O-β-xylopyranoside, cupressuflavone, podocarpusflavone A, and hinokiflavone as major components based on phytochemical analysis. Eight flavonoids were isolated from JFE, and of those, cupressuflavone and isoscutellarein-7-O-β-xylopyranoside strongly down-regulated IL-4 expression and β-hexosaminidase release in RBL-2H3 cells.

CONCLUSION

Therapeutic attempts with J. rigida fruit and its active components might be useful in treating AD and related skin inflammatory diseases.

Mast cells and sphingosine-1-phosphate underlie prelesional remodeling in a mouse model of eczema

BACKGROUND

Atopic dermatitis (AD) is a chronic skin inflammation that affects children and adults worldwide, but its pathogenesis remains ill-understood.

METHODS

We show that a single application of OVA to mouse skin initiates remodeling and cellular infiltration of the hypodermis measured by a newly developed computer-aided method.

RESULTS

Importantly, we demonstrate that skin mast cell (MC) activation and local sphingosine-1-phosphate (S1P) are significantly augmented after OVA treatment in mice. Deficiency in sphingosine kinase (SphK)1, the S1P-producing enzyme, or in MC, remarkably mitigates all signs of OVA-mediated remodeling and MC activation. Furthermore, skin S1P levels remain unchanged in MC-deficient mice exposed to OVA. LPS-free OVA does not recapitulate any of the precursor signs of AD, supporting a triggering contribution of LPS in AD that, per se, suffice to activate local MC and elevate skin S1P.

CONCLUSION

We describe MC and S1P as novel pathogenic effectors that initiate remodeling in AD prior to any skin lesions and reveal the significance of LPS in OVA used in most studies, thus mimicking natural antigen (Ag) exposure.

Dioscorea quinqueloba Ameliorates Oxazolone- and 2,4-Dinitrochlorobenzene-induced Atopic Dermatitis Symptoms in Murine Models

Dioscorea quinqueloba has been used for food substances, as well as in herbal medicines for allergic diseases such as asthma. This study aimed to investigate the anti-atopic dermatitis (AD) effects of the total extract of D. quinqueloba rhizomes and active fractionson murine oxazolone- and 2,4-dinitrochlorobenzene-induced models of AD. Specific AD symptoms, such as erythema, ear swelling, and epidermis thickening, were significantly reduced in the oxazolone-mediated AD BALB/c mice upon topical application of D. quinqueloba rhizomes 95% EtOH extract (DQ). DQEA (D. quinqueloba rhizomes EtOAc fraction) was beneficial for protecting the skin barrier against AD in DNCB-sensitized SKH-1 hairless mice. Decreased total serum IgE and IL-4 levels could be observed in atopic dorsal skin samples of the DQEA-treated group. On the basis of the phytochemical analysis, DQEA was found to contain dioscin and gracillin as its main compounds. Therapeutic applications with D. quinqueloba might be useful in the treatment of AD and related inflammatory skin diseases.

The role of β-blockers in dermatological treatment: a review

Many systemic medications have been used off-label in cutaneous diseases. Use of β-adrenergic-blocking agents has risen in popularity among dermatologists since the discovery of their efficacy in treating infantile haemangioma. There has also been an increase in the interest of the applications of β-blockers in other skin disorders. Overall, β-blockers are effective in treating diseases of vascular origin and promote wound healing. They are relatively safe and inexpensive medications that could be included in the armamentarium against skin diseases.

Long-term treatment with low-dose medicine in chronic childhood eczema: a double-blind two-stage randomized control trial

BACKGROUND

The efficacy of low-dose medicine (LDM) in childhood mild/moderate eczema is not known. We conducted a double-blind, two-stage, randomized, placebo-controlled clinical trial, lasting 23 months, to address this issue.

METHOD

Eighty children with chronic mild/moderate eczema were randomly allocated to Group A (placebo) or Group B (treatment group; Galium-Heel®, a low-dose multicomponent medicine based upon natural substances; Guna-Interleukin 12 and Guna-Interferon-γ administered twice a day for six non-consecutive months for each stage). LDM is characterized by the use of biological molecules, such as cytokines, neuropeptides, growth factors, hormones at very low concentrations, which correspond to physiological levels within the human body. The dosage of the cytokines used in this trial (IFN-γ and IL-12) is 10 fg/ml. The SCORAD index was evaluated by the same operator: subjects with a SCORAD index below 20 were considered to have mild eczema (61/80; mean: 10.79), whereas a SCORAD index between 20-50 indicated moderate eczema (19/80; mean: 26.84). The data of 66/80 children were analyzed in stage 1 and those of 62/66 children in stage 2. The primary outcome measure was reduction of eczema severity assessed by the SCORAD index. Secondary outcomes were disease-free interval, and treatment safety and tolerability.

RESULTS

The decrease in disease severity was greater in Group B than in Group A already in stage 1 (a decrease 63.9% versus 53.2%), but the difference was not significant (p = 0.16). Moreover, subjective symptoms (itching and sleep disturbances) initially decreased and then worsened in Group A, whereas itching decreased linearly and sleep disturbances decreased significantly (p=0.049) in Group B.

CONCLUSIONS

Preliminary evidence suggests potential benefit, but further work is needed to validate this approach.

TRIAL REGISTRATION

The trial was registered with EudraCT number 2010-018640-13 through the database of the National Clinical Trials Monitoring Centre Database (Osservatorio delle Sperimentazioni Cliniche, OsSC) of the Italian Medicines Agency.

Prevalence of comorbidity and associated risk factors in adults with atopic dermatitis

BACKGROUND

Atopic dermatitis (AD) is a common chronic skin disorder, which may persist into adulthood; however, the prevalence of comorbidities in patients with AD is not well characterized. AD is considered a systemic disorder like psoriasis, which has raised a need for data on the comorbidity profile of patients with AD, to assess the potential risks, benefits, and complications in management of patients with AD. We described the occurrence of medical and psychiatric comorbidities and associated risk factors in adults with AD compared with psoriasis and the general population.

METHODS

All Danish individuals aged ≥18 years with a hospital (inpatient or ambulatory) diagnosis of AD or psoriasis during the study period (January 1, 1995-December 31, 2012) were linked in administrative registers.

RESULTS

Overall, prevalence of smoking and alcohol abuse was higher among patients with AD than the general population, but lower than psoriasis patients. Similarly, patients with AD had more risk factors and higher prevalence of comorbidity than the general population, but lower prevalence and reduced risk compared to psoriasis patients, except for use of anxiolytics, which was higher in severe AD. Prevalence of diabetes was lower in AD than psoriasis patients as well as general population controls.

CONCLUSIONS

Despite an increased risk of various medical and psychiatric comorbidities compared to general population controls, adult patients with AD had markedly lower prevalence of cardiovascular disease than psoriasis patients. However, prevalence of psychiatric comorbidity and tobacco smoking was alarmingly high in severe patients with AD, which might be target for intervention in patient management.

Topical treatments of Saussurea costus root and Thuja orientalis L. synergistically alleviate atopic dermatitis-like skin lesions by inhibiting protease-activated receptor-2 and NF-κB signaling in HaCaT cells and Nc/Nga mice

ETHNOPHARMACOLOGICAL RELEVANCE

The root of Saussurea costus (Aucklandia lappa Decne, Aucklandiae Radix, SC) and Thuja orientalis L. (TOL) have been traditionally used as anti-inflammatory agents in Korea. However, they have not been studied for the efficacy of atopic dermatitis (AD) treatment, a chronic inflammatory skin disease. We investigated the efficacy of topical applications with 1,3-butyleneglycol extracts of SC and TOL to alleviate the symptoms of AD.

MATERIALS AND METHODS

HaCaT cells and the dorsal skin of Nc/Nga mice had a local exposure of house mite extracts and 2,4-dinitrochlorobenzene (DNCB), respectively. After lesions developed, we topically applied 1,3-butylen glycol (vehicle; control), SC (30%), TOL (30%), or SC (15%)+TOL (15%) to the skin lesions for 5 weeks. The normal-control was not exposed to DNCB. The skin thickness, mast cell infiltration, serum immunoglobulin E (IgE) and IgG1 and gene expressions of interleukin (IL)-4, IL-13, and IFN-γ in the dorsal skin and HaCaT cells were measured.

RESULTS

Chlorogenic acid (129.6±10.2μg/g) for SC and catechin and apigenin (93.4±13.2 and 16.9±1.3μg/g, respectively) for TOL were used as indicator compounds for the strength of the extracts. SC+TOL decreased the expression of protease-activated receptor-2 and ICAM-1 and the release of TNF-α and IL-6 in HaCaT cells activated by 3μg/mL house mite extracts in comparison to either of SC or TOL alone. In Nc/Nga mice challenged with DNCB, SC+TOL synergistically attenuated clinical symptoms of AD such as erythema, hemorrhage, edema, excoriation and dryness in the dorsal skin better than either SC or TOL alone. Histological analysis of the dorsal skin also showed that SC+TOL treatment significantly and additively decreased the inflammatory cellular infiltrate, including mast cells and eosinophils in comparison to either of SC or TOL. SC+TOL also decreased serum IgE and IgG1 levels and the expression of IFN-γ, IL-4, and IL-13 mRNA in dorsal skin in DNCB-treated Nc/Nga mice.

CONCLUSION

SC+TOL relieved the symptoms of AD by reducing pro-inflammatory activity and over-activated immune responses. These data suggest that SC+TOL may be an effective alternative intervention for the management of AD.

Disentangling genetic and environmental risk factors for individual diseases from multiplex comorbidity networks

Most disorders are caused by a combination of multiple genetic and/or environmental factors. If two diseases are caused by the same molecular mechanism, they tend to co-occur in patients. Here we provide a quantitative method to disentangle how much genetic or environmental risk factors contribute to the pathogenesis of 358 individual diseases, respectively. We pool data on genetic, pathway-based, and toxicogenomic disease-causing mechanisms with disease co-occurrence data obtained from almost two million patients. From this data we construct a multiplex network where nodes represent disorders that are connected by links that either represent phenotypic comorbidity of the patients or the involvement of a certain molecular mechanism. From the similarity of phenotypic and mechanism-based networks for each disorder we derive measure that allows us to quantify the relative importance of various molecular mechanisms for a given disease. We find that most diseases are dominated by genetic risk factors, while environmental influences prevail for disorders such as depressions, cancers, or dermatitis. Almost never we find that more than one type of mechanisms is involved in the pathogenesis of diseases.

Resolving the etiology of atopic disorders by using genetic analysis of racial ancestry

Atopic dermatitis (AD), food allergy, allergic rhinitis, and asthma are common atopic disorders of complex etiology. The frequently observed atopic march from early AD to asthma, allergic rhinitis, or both later in life and the extensive comorbidity of atopic disorders suggest common causal mechanisms in addition to distinct ones. Indeed, both disease-specific and shared genomic regions exist for atopic disorders. Their prevalence also varies among races; for example, AD and asthma have a higher prevalence in African Americans when compared with European Americans. Whether this disparity stems from true genetic or race-specific environmental risk factors or both is unknown. Thus far, the majority of the genetic studies on atopic diseases have used populations of European ancestry, limiting their generalizability. Large-cohort initiatives and new analytic methods, such as admixture mapping, are currently being used to address this knowledge gap. Here we discuss the unique and shared genetic risk factors for atopic disorders in the context of ancestry variations and the promise of high-throughput "-omics"-based systems biology approach in providing greater insight to deconstruct their genetic and nongenetic etiologies. Future research will also focus on deep phenotyping and genotyping of diverse racial ancestry, gene-environment, and gene-gene interactions.

[New populations at increased cardiovascular risk: Cardiovascular disease in dermatological diseases]

The increased cardiovascular risk in some dermatological diseases has been demonstrated in recent decades. Diseases such as psoriasis and systemic lupus erythematosus are currently included in the guidelines for prevention of cardiovascular disease. Other diseases such as androgenic alopecia, polycystic ovary syndrome, hidradenitis suppurativa or lichen planus have numerous studies that point to an increased risk, however, they have not been included in these guidelines. In this article we review the evidence supporting this association, in order to alert the clinician to the need for greater control in cardiovascular risk factors in these patients.

Associations among plasma vitamin C, epidermal ceramide and clinical severity of atopic dermatitis

BACKGROUND/OBJECTIVES

Atopic dermatitis (AD), a chronic inflammatory skin disease, is accompanied by disruption of the epidermal lipid barrier, of which ceramide (Cer) is the major component. Recently it was reported that vitamin C is essential for de novo synthesis of Cer in the epidermis and that the level of vitamin C in plasma is decreased in AD. The objective of this study was to determine the associations among clinical severity, vitamin C in either plasma or epidermis, and Cer in the epidermis of patients with AD.

SUBJECTS/METHODS

A total of 17 patients (11 male and 6 female) aged 20-42 years were enrolled. The clinical severity of AD was assessed according to the SCORAD (SCORing Atopic Dermatitis) system. Levels of vitamin C were determined in plasma and biopsies of lesional epidermis. Levels of epidermal lipids, including Cer, were determined from tape-stripped lesional epidermis.

RESULTS

The clinical severity of patients ranged between 0.1 and 45 (mild to severe AD) based on the SCORAD system. As the SCORAD score increased, the level of vitamin C in the plasma, but not in the epidermis, decreased, and levels of total Cer and Cer2, the major Cer species in the epidermis, also decreased. There was also a positive association between level of vitamin C in the plasma and level of total Cer in the epidermis. However, levels of epidermal total lipids including triglyceride, cholesterol, and free fatty acid (FFA) were not associated with either SCORAD score or level of vitamin C in the plasma of all subjects.

CONCLUSIONS

As the clinical severity of AD increased, level of vitamin C in the plasma and level of epidermal Cer decreased, and there was a positive association between these two parameters, implying associations among plasma vitamin C, epidermal Cer, and the clinical severity of AD.

Gene signature-based mapping of immunological systems and diseases

Background

The immune system is multifaceted, structured by diverse components that interconnect using multilayered dynamic cellular processes. Genomic technologies provide a means for investigating, at the molecular level, the adaptations of the immune system in host defense and its dysregulation in pathological conditions. A critical aspect of intersecting and investigating complex datasets is determining how to best integrate genomic data from diverse platforms and heterogeneous sample populations to capture immunological signatures in health and disease.

Result

We focus on gene signatures, representing highly enriched genes of immune cell subsets from both diseased and healthy tissues. From these, we construct a series of biomaps that illustrate the molecular linkages between cell subsets from different lineages, the connectivity between different immunological diseases, and the enrichment of cell subset signatures in diseased tissues. Finally, we overlay the downstream genes of drug targets with disease gene signatures to display the potential therapeutic applications for these approaches.

Conclusion

An in silico approach has been developed to characterize immune cell subsets and diseases based on the gene signatures that most differentiate them from other biological states. This modular ‘biomap’ reveals the linkages between different diseases and immune subtypes, and provides evidence for the presence of specific immunocyte subsets in mixed tissues. The over-represented genes in disease signatures of interest can be further investigated for their functions in both host defense and disease.

Electronic supplementary material

The online version of this article (doi:10.1186/s12859-016-1012-y) contains supplementary material, which is available to authorized users.

Comorbidity of Atopic Disorders with Autism Spectrum Disorder and Attention Deficit/Hyperactivity Disorder

OBJECTIVE

To assess the relationship between allergic manifestations in early life and the occurrence of newly diagnosed autism spectrum disorder (ASD) and attention deficit/hyperactivity disorder (ADHD) throughout childhood.

STUDY DESIGN

We collected a population-based longitudinal cohort comprising children enrolled in Taiwan's National Health Insurance Program during 2000-2010. We first identified 387,262 children who had a diagnosis of atopic dermatitis (AD) before age 2 years, with 1:1 individualized matching to children without AD. Cox regression analyses were performed to estimate the early-onset and cumulative effects of allergic manifestations on ASD and ADHD.

RESULTS

An estimated 0.5% of AD-exposed children received a diagnosis of ASD, and 3.7% were diagnosed with ADHD, significantly higher than the respective rates of 0.4% and 2.9% found in their nonexposed peers. Having AD before age 2 years was associated with an increased hazard ratio (HR) for ASD by 10% and that for ADHD by 16%; such increases were particularly prominent among those with earlier-onset or more severe AD. HRs were especially higher for children with persistent AD and emerging atopic respiratory diseases in childhood (eg, for ASD, adjusted HR, 1.75 and 2.13, respectively; P < .001).

CONCLUSION

The observed increased risks of ASD and ADHD associated with AD in infancy suggest that a disordered immunologic response may exert effects on neurodevelopment and have implications for research into etiology and treatment strategies.

Oral Administration of p-Hydroxycinnamic Acid Attenuates Atopic Dermatitis by Downregulating Th1 and Th2 Cytokine Production and Keratinocyte Activation

Atopic dermatitis (AD) is a complex disease that is caused by various factors, including environmental change, genetic defects, and immune imbalance. We previously showed that p-hydroxycinnamic acid (HCA) isolated from the roots of Curcuma longa inhibits T-cell activation without inducing cell death. Here, we demonstrated that oral administration of HCA in a mouse model of ear AD attenuates the following local and systemic AD manifestations: ear thickening, immune-cell infiltration, production of AD-promoting immunoregulatory cytokines in ear tissues, increased spleen and draining lymph node size and weight, increased pro-inflammatory cytokine production by draining lymph nodes, and elevated serum immunoglobulin production. HCA treatment of CD4+ T cells in vitro suppressed their proliferation and differentiation into Th1 or Th2 and their Th1 and Th2 cytokine production. HCA treatment of keratinocytes lowered their production of the pro-inflammatory cytokines that drive either Th1 or Th2 responses in AD. Thus, HCA may be of therapeutic potential for AD as it acts by suppressing keratinocyte activation and downregulating T-cell differentiation and cytokine production.

Multiple Transcriptome Data Analysis Reveals Biologically Relevant Atopic Dermatitis Signature Genes and Pathways

Several studies have identified genes that are differentially expressed in atopic dermatitis (AD) compared to normal skin. However, there is also considerable variation in the list of differentially expressed genes (DEGs) reported by different groups and the exact cause of AD is still not fully understood. Using a rank-based approach, we analyzed gene expression data from five different microarray studies, comprising a total of 127 samples and more than 250,000 transcripts. A total of 89 AD gene expression signatures '89ADGES', including FLG gene, were identified to show dysregulation consistently across these studies. Using a Support Vector Machine, we showed that the '89ADGES' discriminates AD from normal skin with 98% predictive accuracy. Functional annotation of these genes implicated their roles in immune responses (e.g., betadefensin, microseminoprotein), keratinocyte differentiation/epidermal development (e.g., FLG, CORIN, AQP, LOR, KRT16), inflammation (e.g., IL37, IL27RA, CCL18) and lipid metabolism (e.g., AKR1B10, FAD7, FAR2). Subsequently, we validated a subset of signature genes using quantitative PCR in a mouse model. Using a bioinformatic approach, we identified keratinocyte pathway over-represented (P = <0.0006) among the 89 signature genes. Keratinocytes are known to play a major role in barrier function due to their location in the epidermis. Our result suggests that besides immune- mediated pathway, skin barrier pathways such as the keratinocyte differentiation pathway play a key role in AD pathogenesis. A better understanding of the role of keratinocytes in AD will be important for developing novel "barrier therapy" for this disease.

Association Between Atopic Dermatitis and Autism Spectrum Disorders: A Systematic Review

BACKGROUND

Atopic dermatitis (AD) is an allergic disorder caused by both immunological dysregulation and epidermal barrier defect. Several studies have investigated the association between AD and mental health disorders. Autism spectrum disorders (ASD) are a heterogeneous group of neurodevelopmental conditions characterized by impairments in social communication and restricted, stereotyped interests and behaviors. The concurrent increased prevalence of AD and ASD in the last decades has led many scientists to investigate the relationship between the two diseases.

OBJECTIVE

The aim of this systematic review was to examine the association between AD and ASD.

METHODS

A systematic review was performed according to the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. PubMed and ScienceDirect were searched up to March 2015 for all reports examining the association between ASD and AD. Descriptive statistics of the studies are reported.

RESULTS

The review included 18 studies assessing the association between ASD and AD. Of these studies, two focused on ASD in relation to AD alone, 14 discussed ASD in relation to both AD and other atopic disorders, and two evaluated AD in parents of children with ASD. Most of these studies found a positive association between the two disorders, although there were some studies going in the opposite direction. The entity of the association is somewhat inconsistent among the different studies given that the frequencies of AD in ASD compared with a control group ranged from 7 to 64.2%. In addition, odds ratios (ORs) or hazard ratios (HRs) gave different results as three studies found a weak association with an OR below 2 and a nonsignificant p value, and three other studies found a moderate or strong association with an OR ranging from 1.52 to 7.17 and a significant p value. When all atopic disorders were considered when evaluating the risk of ASD, the association was strong with an HR of 3.4 or an OR of 1.24 and p < 0.001.

CONCLUSIONS

Overall, the results of this systematic review seem to reveal an association between ASD and AD, suggesting that subjects with ASD have an increased risk of presenting with AD compared with typically developing controls, and vice versa. This association is supported by clinical/epidemiological aspects, shared genetic background and common immunological and autoimmune processes. However, the variability in study population and design, and the presence of other risk factors acting as confounding factors, sometimes contribute to inconsistent results. Further studies are needed to clarify the underlying pathophysiologic mechanism explaining the association between ASD and AD and to explore the causal association between the two conditions.

Evoked itch perception is associated with changes in functional brain connectivity

Chronic itch, a highly debilitating condition, has received relatively little attention in the neuroimaging literature. Recent studies suggest that brain regions supporting itch in chronic itch patients encompass sensorimotor and salience networks, and corticostriatal circuits involved in motor preparation for scratching. However, how these different brain areas interact with one another in the context of itch is still unknown. We acquired BOLD fMRI scans in 14 atopic dermatitis patients to investigate resting-state functional connectivity before and after allergen-induced itch exacerbated the clinical itch perception in these patients. A seed-based analysis revealed decreased functional connectivity from baseline resting state to the evoked-itch state between several itch-related brain regions, particularly the insular and cingulate cortices and basal ganglia, where decreased connectivity was significantly correlated with increased levels of perceived itch. In contrast, evoked itch increased connectivity between key nodes of the frontoparietal control network (superior parietal lobule and dorsolateral prefrontal cortex), where higher increase in connectivity was correlated with a lesser increase in perceived itch, suggesting that greater interaction between nodes of this executive attention network serves to limit itch sensation via enhanced top-down regulation. Overall, our results provide the first evidence of itch-dependent changes in functional connectivity across multiple brain regions.

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Atopic dermatitis patients were subjected to allergen-induced itch.

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Evoked itch reduced functional connectivity between itch-related brain regions.

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Evoked itch increased functional connectivity within frontoparietal control network.

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The above changes in functional connectivity correlated with perceived itch level.

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Itch sensation may be top-down regulated by frontoparietal control network.