Associations of particulate matter with atopic dermatitis and chronic inflammatory skin diseases in South Korea

Decoding the impact of ageing and environment stressors on skin cell communication

The integumentary system serves as a crucial protective barrier and is subject to complex signaling pathways that regulate its physiological functions. As the body's first line of defense, the skin is continuously exposed to environmental stressors, necessitating a robust network of signaling molecules to maintain homeostasis. Considering the main cellular components to be keratinocytes, melanocytes, fibroblasts, and fibrous components, collagen of various types, this review explores the intricate signaling mechanisms that govern skin integrity, focusing on key pathways involved in impacts of ageing and environment factors on skin health. The role of growth factors, cytokines, hormones and other molecular mediators in these processes is examined. Specially for women, decrease of estrogen is determinant to alter signaling and to compromise skin structure, especially the dermis. Environmental factors, such as ultraviolet rays and pollution alongside the impact of ageing on signaling pathways, especially TGF-β and proteases (metalloproteinases and cathepsins). Furthermore, with advancing age, the skin's capacity to shelter microbiome challenges diminishes, leading to alterations in signal transduction and subsequent functional decline. Understanding these age-related changes is essential for developing targeted therapies aimed at enhancing skin health and resilience, but also offers a promising avenue for the treatment of skin disorders and the promotion of healthy ageing.

Geraniin from the methanol extract of Pilea mongolica suppresses LPS-induced inflammatory responses by inhibiting IRAK4/MAPKs/NF-κB/AP-1 pathway in HaCaT cells

The skin acts as a vital barrier, shielding the body from external threats that can trigger dryness, itching, and inflammation. Pilea mongolica, a traditional Chinese medicinal herb, holds promise for various ailments, yet its anti-inflammatory properties remain understudied. This study aimed to explore the potential anti-inflammatory effects of the methanol extract of P. mongolica (MEPM) and its underlying molecular mechanisms and active compounds in LPS-stimulated human keratinocytes. MEPM treatment, at concentrations without cytotoxicity, significantly decreased NO productions and the iNOS, IL-6, IL-1β, and TNF-α levels in LPS-induced HaCaT cells. Moreover, MEPM suppressed IRAK4 expression and phosphorylation of JNK, ERK, p38, p65, and c-Jun, suggesting that the anti-inflammatory effects of MEPM result from the inhibition of IRAK4/MAPK/NF-κB/AP-1 signaling pathway. Through LC/MS/MS analysis, 30 compounds and 24 compounds were estimated in negative and positive modes, respectively, including various anti-inflammatory compounds, such as corilagin and geraniin. Through HPLC analysis, geraniin was found to be present in MEPM at a concentration of 18.87 mg/g. Similar to MEPM, geraniin reduced iNOS mRNA expression and inhibited NO synthesis. It also decreased mRNA and protein levels of inflammatory cytokines, including IL-6 and TNF-α, and inhibited IRAK4 expression and the phosphorylation of MAPKs, NF-κB, and AP-1 pathways. Therefore, it can be inferred that the anti-inflammatory effects of MEPM are attributable to geraniin. Thus, MEPM and its active compound geraniin are potential candidates for use in natural functional cosmetics.

Particulate Matter and Its Molecular Effects on Skin: Implications for Various Skin Diseases

Particulate matter (PM) is a harmful air pollutant composed of chemicals and metals which affects human health by penetrating both the respiratory system and skin, causing oxidative stress and inflammation. This review investigates the association between PM and skin disease, focusing on the underlying molecular mechanisms and specific disease pathways involved. Studies have shown that PM exposure is positively associated with skin diseases such as atopic dermatitis, psoriasis, acne, and skin aging. PM-induced oxidative stress damages lipids, proteins, and DNA, impairing cellular functions and triggering inflammatory responses through pathways like aryl hydrocarbon receptor (AhR), NF-κB, and MAPK. This leads to increased production of inflammatory cytokines and exacerbates skin conditions. PM exposure exacerbates AD by triggering inflammation and barrier disruption. It disrupts keratinocyte differentiation and increases pro-inflammatory cytokines in psoriasis. In acne, it increases sebum production and inflammatory biomarkers. It accelerates skin aging by degrading ECM proteins and increasing MMP-1 and COX2. In conclusion, PM compromises skin health by penetrating skin barriers, inducing oxidative stress and inflammation through mechanisms like ROS generation and activation of key pathways, leading to cellular damage, apoptosis, and autophagy. This highlights the need for protective measures and targeted treatments to mitigate PM-induced skin damage.

Deciphering the links: Fragmented polystyrene as a driver of skin inflammation

Nano- and microplastics (NMPs), ubiquitous in the environment, pose significant health risks. We report for the first time a comprehensive study using in-vitro, in-vivo, and ex-vivo models to investigate the penetration and inflammatory effects of fragmented polystyrene (fPS) on human skin, including the analysis of both penetration depth and fPS amounts that penetrate the skin. Human keratinocyte (HaCaT) and human dermal fibroblast (HDF) cells exposed to fPS exhibited notable internalization and cytotoxicity. In a 3D human skin model, fPS particles penetrated the dermal layer within one hour, with an average maximum penetration of 4.7 μg for particles smaller than 2 µm. Similarly, mouse dorsal skin and human abdominal skin models confirmed fPS penetration. RNA sequencing revealed substantial upregulation of inflammatory genes, including IL-1α, IL-1β, IL-18, IL-6, IL-8, ICAM-1, FOS, and JUN, following fPS exposure. These findings were validated at both the mRNA and protein levels, indicating a robust inflammatory response. Notably, the inflammatory response in both the 3D human skin and mouse models increased in a dose-dependent manner, underscoring the toxicological impact of fPS on skin health. This study provides crucial insights into the mechanisms through which NMPs affect human health and underscores the need for further research to develop effective mitigation strategies.

Association between United States Environmental Contaminants and the Prevalence of Psoriasis Derived from the National Health and Nutrition Examination Survey

(1) Background: Prolonged coexposure to environmental contaminants is reportedly associated with adverse impacts on skin health. However, the collective effects of contaminant mixtures on psoriasis prevalence remain unclear. (2) Methods: A nationally representative cohort study was conducted using data from the National Health and Nutrition Examination Survey 2003-2006 and 2009-2014. The association between contaminant exposures and psoriasis prevalence was analyzed through weighted quantile sum regressions, restricted cubic splines, and multivariable logistic regression. (3) Results: 16,453 participants and 60 contaminants in 8 groups were involved. After adjusting for demographics and comorbidities, exposure to urinary perchlorate, nitrate, and thiocyanate mixtures (OR: 1.10, 95% CI: 1.00-1.21) demonstrated a significant positive linear association with psoriasis prevalence. Ethyl paraben (OR: 1.21, 95% CI: 1.02-1.44) exhibited a significant positive correlation with psoriasis risk as an individual contaminant. The association between blood cadmium, lead, and mercury mixtures (OR: 1.10, 95% CI: 1.00-1.21), urinary perchlorate, nitrate, and thiocyanate mixtures (OR: 1.16, 95% CI: 1.00-1.34), and psoriasis prevalence was more pronounced in the lower healthy lifestyle score subgroup. (4) Conclusions: Exposure to perchlorate, nitrate, and thiocyanate mixtures, and ethyl paraben was associated with an elevated psoriasis prevalence. Furthermore, the association between cadmium and lead and mercury mixtures as well as perchlorate, nitrate and thiocyanate mixtures, and psoriasis prevalence was more pronounced in individuals with less healthy lifestyles.

Predicting the daily number of patients for allergic diseases using PM10 concentration based on spatiotemporal graph convolutional networks

Air pollution causes and exacerbates allergic diseases including asthma, allergic rhinitis, and atopic dermatitis. Precise prediction of the number of patients afflicted with these diseases and analysis of the environmental conditions that contribute to disease outbreaks play crucial roles in the effective management of hospital services. Therefore, this study aims to predict the daily number of patients with these allergic diseases and determine the impact of particulate matter (PM10) on each disease. To analyze the spatiotemporal correlations between allergic diseases (asthma, atopic dermatitis, and allergic rhinitis) and PM10 concentrations, we propose a multi-variable spatiotemporal graph convolutional network (MST-GCN)-based disease prediction model. Data on the number of patients were collected from the National Health Insurance Service from January 2013 to December 2017, and the PM10 data were collected from Airkorea during the same period. As a result, the proposed disease prediction model showed higher performance (R2 0.87) than the other deep-learning baseline methods. The synergic effect of spatial and temporal analyses improved the prediction performance of the number of patients. The prediction accuracies for allergic rhinitis, asthma, and atopic dermatitis achieved R2 scores of 0.96, 0.92, and 0.86, respectively. In the ablation study of environmental factors, PM10 improved the prediction accuracy by 10.13%, based on the R2 score.

Effects and mechanisms of polycyclic aromatic hydrocarbons in inflammatory skin diseases

Polycyclic aromatic hydrocarbons (PAHs) are hydrocarbons characterized by the presence of multiple benzene rings. They are ubiquitously found in the natural environment, especially in environmental pollutants, including atmospheric particulate matter, cigarette smoke, barbecue smoke, among others. PAHs can influence human health through several mechanisms, including the aryl hydrocarbon receptor (AhR) pathway, oxidative stress pathway, and epigenetic pathway. In recent years, the impact of PAHs on inflammatory skin diseases has garnered significant attention, yet many of their underlying mechanisms remain poorly understood. We conducted a comprehensive review of articles focusing on the link between PAHs and several inflammatory skin diseases, including psoriasis, atopic dermatitis, lupus erythematosus, and acne. This review summarizes the effects and mechanisms of PAHs in these diseases and discusses the prospects and potential therapeutic implications of PAHs for inflammatory skin diseases.

Spatial modeling connecting childhood atopic dermatitis prevalence with household exposure to pollutants

BACKGROUND

Atopic dermatitis (AD) is a chronic, inflammatory disease characterized by dry, pruritic skin. In the U.S., the prevalence of AD has increased over three-fold since the 1970s. We previously reported a geographic association between isocyanate-containing air pollution and AD as well as mechanistic data demonstrating that isocyanates induce skin dysbiosis and activate the host itch receptor TRPA1. However, non-spatial models are susceptible to spatial confounding and may overlook other meaningful associations.

METHODS

We added spatial analysis to our prior model, contrasting pollution data with clinical visits. In addition, we conducted a retrospective case-control survey of childhood exposure to BTEX-related products. Finally, we assessed implicated compounds, in pure form and as part of synthetic fabric, for their effect on the growth and metabolism of skin commensal bacteria.

RESULTS

Spatial analysis implicate benzene, toluene, ethylbenzene, and, most significantly, xylene (BTEX) compounds. Survey odds ratios for AD were significant for xylene-derived polyester bed sheets (OR = 9.5; CI 2.2-40.1) and diisocyanate-containing wallpaper adhesive (OR = 6.5; CI 1.5-27.8). Staphylococcus aureus lives longer on synthetic textiles compared to natural textiles. Meanwhile, synthetic fabric exposure shifts the lipid metabolism of health-associated commensals (Roseomonas mucosa and S. epidermidis) away from therapeutic pathways.

CONCLUSIONS

We propose that BTEX chemicals in their raw forms and in synthetic products represent a unifying hypothesis for environmentally induced AD flares through their ability to create dysbiosis in the skin microbiota and directly activate TRPA1. Unequal distribution of these pollutants may also influence racial disparities in AD rates.

Particulate matter stimulates the NADPH oxidase system via AhR-mediated epigenetic modifications

Stimulation of human keratinocytes with particulate matter 2.5 (PM2.5) elicits complex signaling events, including a rise in the generation of reactive oxygen species (ROS). However, the mechanisms underlying PM2.5-induced ROS production remain unknown. Here, we show that PM2.5-induced ROS production in human keratinocytes is mediated via the NADPH oxidase (NOXs) system and the Ca2+ signaling pathway. PM2.5 treatment increased the expression of NOX1, NOX4, and a calcium-sensitive NOX, dual oxidase 1 (DUOX1), in human epidermal keratinocyte cell line. PM2.5 bound to aryl hydrocarbon receptor (AhR), and this complex bound to promoter regions of NOX1 and DUOX1, suggesting that AhR acted as a transcription factor of NOX1 and DUOX1. PM2.5 increased the transcription of DUOX1 via epigenetic modification. Moreover, a link between DNA demethylase and histone methyltransferase with the promoter regions of DUOX1 led to an elevation in the expression of DUOX1 mRNA. Interestingly, PM2.5 increased NOX4 expression and promoted the interaction of NOX4 and Ca2+ channels within the cytoplasmic membrane or endoplasmic reticulum, leading to Ca2+ release. The increase in intracellular Ca2+ concentration activated DUOX1, responsible for ROS production. Our findings provide evidence for a PM2.5-mediated ROS-generating system network, in which increased NOX1, NOX4, and DUOX1 expression serves as a ROS signal through AhR and Ca2+ activation.

Air pollutants contribute to epithelial barrier dysfunction and allergic diseases

Air pollution is a global problem associated with various health conditions, causing elevated rates of morbidity and mortality. Major sources of air pollutants include industrial emissions, traffic-related pollutants, and household biomass combustion, in addition to indoor pollutants from chemicals and tobacco. Various types of air pollutants originate from both human activities and natural sources. These include particulate matter, pollen, greenhouse gases, and other harmful gases. Air pollution is linked to allergic diseases, including atopic dermatitis, allergic rhinitis, allergic conjunctivitis, food allergy, and bronchial asthma. These pollutants lead to epithelial barrier dysfunction, dysbiosis, and immune dysregulation. In addition, climate change and global warming may contribute to the exacerbation and the development of allergic diseases related to air pollutants. Epigenetic changes associated with air pollutants have also been connected to the onset of allergic diseases. Furthermore, these changes can be passed down through subsequent generations, causing a higher prevalence of allergic diseases in offspring. Modulation of the aryl hydrocarbon receptor could be a valuable strategy for alleviating air pollutant-induced epidermal barrier dysfunction and atopic dermatitis. A more effective approach to preventing allergic diseases triggered by air pollutants is to reduce exposure to them. Implementing public policies aimed at safeguarding individuals from air pollutant exposure may prove to be the most efficient solution. A pressing need exists for global policy initiatives that prioritize efforts to reduce the production of air pollutants.

A simple air-liquid interface exposure system for exposing cultured human 3D epidermis and cornea to PM2.5 collected through cyclonic separation

Particulate matter (PM) is among the major air pollutants suspended in the atmosphere. PM2.5 has a particle size of 2.5 µm; it is known to cause inflammation, especially in the respiratory tract and skin. Since the skin acts a primary barrier against harmful environmental substances that may enter the body, it is highly exposed to PM2.5 present in the environment. However, the adverse health effects of PM2.5 exposure on human skin have not been accurately examined due to the lack of a system that exposes human epidermal tissue to the actual environmental concentration of PM2.5. In this study, we developed an air-liquid interface exposure system for exposing cultured human 3D epidermis and cornea to PM2.5 collected through cyclonic separation. PM2.5 suspension was nebulized in an acrylic chamber, and the resulting mist was pumped through a diffusion dryer into a glass exposure chamber. A particle counter was connected to the exposure chamber to continuously measure the spatial mass concentration of PM. Human 3D epidermis was cultured in the exposure chamber. Exposure of the human 3D epidermis to PM aerosol increased interleukin-8 release into the media around 50 µg/m3. Mass concentrations above 100 µg/m3 caused cell death. Furthermore, a human corneal model showed similar responses against PM2.5 exposure as 3D epidermis. The air-liquid interface exposure system developed in this study is considered useful for evaluating the health effects induced by environmental PM2.5 and can be used as an alternative to experiments involving actual human or animals.

Particulate matter and inflammatory skin diseases: From epidemiological and mechanistic studies

Epidemiological and toxicological studies have confirmed that exposure to atmospheric particulate matter (PM) could affect our cardiovascular and respiratory systems. Recent studies have shown that PM can penetrate the skin and cause skin inflammation, but the evidence is limited and contradictory. As the largest outermost surface of the human body, the skin is constantly exposed to the environment. The aim of this study was to assess the relationship between PM and inflammatory skin diseases. Most epidemiological studies have provided positive evidence for outdoor, indoor, and wildfire PM and inflammatory skin diseases. The effects of PM exposure during pregnancy and inflammatory skin diseases in offspring are heterogeneous. Skin barrier dysfunction, Oxidative stress, and inflammation may play a critical role in the underlying mechanisms. Finally, we summarize some interventions to alleviate PM-induced inflammatory skin diseases, which may contribute to public health welfare. Overall, PM is related to inflammatory skin diseases via skin barrier dysfunction, oxidative stress, and inflammation. Appropriate government interventions are beneficial.

Physical influences on the skin barrier and pathogenesis of allergy

PURPOSE OF REVIEW

As the incidence of allergic conditions has increased in recent decades, the effects of climate change have been implicated. There is also increased knowledge on the effects of other physical influences, such as scratching and Staphylococcus aureus . The skin barrier is the first line of defense to the external environment, so understanding the ways that these factors influence skin barrier dysfunction is important.

RECENT FINDINGS

Although the impact on environmental exposures has been well studied in asthma and other allergic disorders, there is now more literature on the effects of temperature, air pollution, and detergents on the skin barrier. Factors that cause skin barrier dysfunction include extreme temperatures, air pollution (including greenhouse gases and particulate matter), wildfire smoke, pollen, scratching, S. aureus, and detergents.

SUMMARY

Understanding the ways that external insults affect the skin barrier is important to further understand the mechanisms in order to inform the medical community on treatment and prevention measures for atopic conditions.

Indoor particulate matter induces epigenetic changes in companion atopic dogs

The prevalence of atopic dermatitis (AD) is increasing and environmental factors are receiving attention as contributing causes. Indoor air pollutants (IAPs), especially particulate matter (PM) can alter epigenetic markers, DNA methylation (DNAm). Although DNAm-mediated epigenetic changes have been reported to modulate the pathogenesis of AD, their role at high risk of exposure to PM is still unclear. The study investigated the effects of exposure to IAPs in the development of AD and epigenetic changes through DNAm in companion atopic dogs that share indoor environment with their owners. Dogs were divided into two groups: AD (n = 47) and controls (n = 21). The IAPs concentration in each household was measured for 48 h, and a questionnaire on the residential environment was completed in all dogs. Eighteen dogs with AD and 12 healthy dogs were selected for DNAm analysis. In addition, clinical and immunological evaluations were conducted. The concentrations of PM2.5, PM10, and volatile organic compounds (VOCs) were significantly higher in the AD group. Moreover, there were more significant methylation differences in the LDLRAD4, KHSRP, and CTDSP2 genes in connection with PM10 in AD group compared to the controls. The degree of methylation of the LDLRAD4 and CTDSP2 genes was also correlated with related protein productions. The present study revealed that exposure to high indoor PM can cause epigenetic development of AD by methylation of the LDLRAD4, KHSRP, and CTDSP2 genes in dogs. Under the concept of "One Health," improving indoor environments should be considered to prevent the development of AD.

Impact of Air Pollution on Atopic Dermatitis: A Comprehensive Review

Air pollution is associated with multiple health problems worldwide, contributing to increased morbidity and mortality. Atopic dermatitis (AD) is a common allergic disease, and increasing evidence has revealed a role of air pollution in the development of atopic dermatitis. Air pollutants are derived from several sources, including harmful gases such as nitrogen dioxide (NO2), sulfur dioxide (SO2), and carbon monoxide (CO), as well as particulate matter (PM) of various sizes, and bioaerosols. Possible mechanisms linking air pollution to atopic dermatitis include damage to the skin barrier through oxidative stress, increased water loss, physicochemical injury, and an effect on skin microflora. Furthermore, oxidative stress triggers immune dysregulation, leading to enhanced sensitization to allergens. There have been multiple studies focusing on the association between various types of air pollutants and atopic dermatitis. Since there are many confounders in the current research, such as climate, synergistic effects of mixed pollutants, and diversity of study population, it is not surprising that inconsistencies exist between different studies regarding AD and air pollution. Still, it is generally accepted that air pollution is a risk factor for AD. Future studies should focus on how air pollution leads to AD as well as effective intervention measures.

Air pollution and global healthcare use for atopic dermatitis: A systematic review

Increasing air pollution is common around the world, but the impacts of outdoor air pollution exposure on atopic dermatitis (AD) are unclear. We synthesized the current global epidemiologic evidence for air pollution exposure and associated medical visits for AD among adults and children. This review followed PRISMA guidelines, and searches were conducted on PubMed, MEDLINE, Web of Science and EMBASE databases. The searches yielded 390 studies, and after screening, 18 studies around the world assessing at least 5,197,643 medical visits for AD in total were included for the final analysis. We found that exposure to particulate matter ≤2.5 μm in diameter (PM2.5 ) [(10/11) of studies], particulate matter ≤10 μm in diameter (PM10 ) (11/13), nitrogen dioxide (NO2 ) (12/14) and sulfur dioxide (SO2 ) (10/13) was positively associated with AD visits. Results were equivocal for ozone [(4/8) of studies reported positive association] and limited for carbon monoxide [(1/4) of studies reported positive association]. When stratifying results by patient age, patient sex and season, we found that the associations with particulate matter, NO2 and O3 may be affected by temperature. Exposure to selected air pollutants is associated with AD visits, and increasingly poor worldwide air quality may increase global healthcare use for AD.

An atopic dermatitis-like murine model by skin-brushed cockroach Per a 2 and oral tolerance induction by Lactococcus lactis-derived Per a 2

Atopic dermatitis (AD) is a complex, chronic inflammatory skin disease. An estimated 57.5% of asthmatic patients and 50.7% of rhinitis patients are allergic to cockroaches in Taiwan. However, the role of cockroaches in the pathogenesis of AD is undetermined. Oral tolerance might be another strategy for protecting against AD and allergic inflammation by regulating T helper 2 (Th2) immune responses. Aim to examine the underlying immunologic mechanism, we developed an AD-like murine model by skin-brushing with cockroach Per a 2. We also investigated whether the systemic inflammation of AD in this murine model could be improved by specific tolerance to Lactococcus lactis-expressing Per a 2, which was administered orally. Repeated painting of Per a 2 without adjuvant to the skin of mice resulted in increased total IgE, Per a 2-specific IgE, and IgG1, but not IgG2a. In addition, epidermal thickening was significantly increased, there were more scratch episodes, and there were increases in total white blood cells (eosinophil, neutrophil, and lymphocyte) and Th2 cytokines (Interleukin (IL)-4, IL-5, IL-9, and IL-13) in a dose-dependent manner. The results revealed that oral administration of L. lactis-Per a 2 ameliorated Per a 2-induced scratch behavior and decreased the production of total IgE, Per a 2-specific IgE, and IgG1. Furthermore, L. lactis-Per a 2 treatment also suppressed inflammatory infiltration, expressions of thymic stromal lymphopoietin (TSLP) and IL-31 in skin lesions, and downregulated splenic IL-4 and IL-13 in Per a 2-induced AD mice. This study provides evidence supporting that repeated brushing of aeroallergens to the skin leads to atopic dermatitis phenotypes and oral allergen-specific immune tolerance can ameliorate AD-like symptoms and systemic inflammation and prevent progression of atopic march.

The Impact of Air Pollution on Atopic Dermatitis

PURPOSE OF REVIEW

Atopic dermatitis (AD) remains a dermatological disease that imposes a significant burden on society. Air pollution has previously been linked to both the onset and severity of atopic dermatitis. As air pollution remains a critical environmental factor impacting human health, this review seeks to provide an overview of the relationship between different air pollutants and AD.

RECENT FINDINGS

AD can develop from multiple causes that can be broadly grouped into epidermal barrier dysfunction and immune dysregulation. Air pollution imposes significant health risks and includes a wide variety of pollutant types. AD has been linked to outdoor air pollutants such as particulate matter (PM), volatile organic compounds (VOC), gaseous compounds, and heavy metals. Exposure to indoor pollutants such as tobacco smoke and fungal molds has also been associated with an increased incidence of AD. While different pollutants impact distinct molecular pathways in the cell, they mostly converge on ROS product, DNA damage, and dysregulated T-cell activity and cytokine production. The presented review suggests a strengthening tie between air pollution and AD. It points to opportunities for further studies to clarify, as well as potential therapeutic opportunities that leverage the mechanistic relationships between air pollution and AD.

Environmental Exposures may Hold the Key; Impact of Air Pollution, Greenness, and Rural/Farm Lifestyle on Allergic Outcomes

PURPOSE OF REVIEW

There has been an increased prevalence of allergy. Due to this relatively rapid rise, changes in environmental exposures are likely the main contributor. In this review, we highlight literature from the last 3 years pertaining to the role of air pollution, greenness, and the rural/farm lifestyle and their association with the development of allergic sensitization, atopic dermatitis, food allergy, and allergic rhinitis in infancy and childhood. Because asthma has a more complex pathophysiology, it was excluded from this review.

RECENT FINDINGS

Recent studies support a role for air pollution, greenness, and rural/farming lifestyle influencing atopic outcomes that continue to be defined. While many studies have examined singular environmental exposures, the interconnectedness of these exposures and others points to a need for future work to consider an individual's whole exposure. Environmental exposures' influence on atopic disease development remains an ongoing and important area of study.

Chemokine expression in human 3-dimensional cultured epidermis exposed to PM2.5 collected by cyclonic separation

Fine particulate matter (PM2.5) exposure has a risk of inducing several health problems, especially in the respiratory tract. The skin is the largest organ of the human body and is therefore the primary target of PM2.5. In this study, we examined the effects of PM2.5 on the skin using a human 3-dimensional cultured epidermis model. PM2.5 was collected by cyclonic separation in Yokohama, Japan. Global analysis of 34 proteins released from the epidermis revealed that the chemokines, chemokine C-X-C motif ligand 1 (CXCL1) and interleukin 8 (IL-8), were significantly increased in response to PM2.5 exposure. These chemokines stimulated neutrophil chemotaxis in a C-X-C motif chemokine receptor 2-dependent manner. The oxidative stress and signal transducer and activator of transcription 3 pathways may be involved in the increased expression of CXCL1 and IL-8 in the human epidermis model. Interestingly, in the HaCaT human keratinocyte cell line, PM2.5 did not affect chemokine expression but did induce IL-6 expression, suggesting a different effect of PM2.5 between the epidermis model and HaCaT cells. Overall, PM2.5 could induce the epidermis to release chemokines, followed by neutrophil activation, which might cause an unregulated inflammatory reaction in the skin.

Short-term effects of air pollutants on outpatients with psoriasis in a Chinese city with a subtropical monsoon climate

Introduction

Psoriasis is a common skin disease that seriously affects patients' quality of life. The association of air pollutants with psoriasis, and the extent of their effects remains unclear.

Methods

Based on a distributed lag non-linear model, this study explored the short-term effects of air pollutants on outpatients with psoriasis in Hefei, China, between 2015 and 2019 by analyzing the exposure-lag-response relationship, after controlling for confounding influences such as meteorological factors, long-term trends, day of the week, and holidays. Stratified analyses were performed for patients of different ages and genders.

Results

The maximum relative risks of psoriasis outpatients' exposure to SO₂, NO₂, and O₃ were 1.023 (95% confidence intervals (CI): 1.004-1.043), 1.170 (95% CI: 1.046-1.307), and 1.059 (95% CI: 1.030-1.090), respectively. An increase of 10 μg/m ³ of NO₂ was associated with a 2.1% (95% CI: 0.7-3.5%) increase in outpatients with psoriasis, and a decrease of 10 μg/m ³ of O₃ was associated with an 0.8% (95% CI: 0.4-1.2%) increase in outpatients with psoriasis. Stratified analyses showed that male subjects were more sensitive to a change in meteorological factors, while female subjects and outpatients with psoriasis aged 0-17 years old were more sensitive to a change in air pollutants.

Discussion

Short-term air pollutant exposures were associated with outpatients having psoriasis, suggesting that patients and high-risk people with psoriasis should reduce their time spent outside and improve their skin protection gear when air quality is poor.

Short-term exposure to ambient fine particulate matter and psoriasis: A time-series analysis in Beijing, China

Background

Ambient fine particulate matter (PM_2.5) adversely affects human health and has been linked to a variety of skin disorders. However, little is known about the effects of PM_2.5 on psoriasis.

Methods

The Beijing Medical Claim Data for Employees database recorded 500,266 outpatient visits for psoriasis during 2010-2017. A generalized additive quasi-Poisson model was used to examine the relationship between daily PM_2.5 concentrations and outpatient visits for psoriasis with stratification by sex, age, and season.

Results

Short-term exposure to PM_2.5 was associated with outpatient visits for psoriasis-related health concerns. A same-day increase of 10 μg/m³ in PM_2.5 concentrations was associated with a 0.29% (95% confidence interval: 0.26-0.32%) increase in daily outpatient visits for psoriasis. Female and older patients appeared to be more sensitive to the effects of PM_2.5 (P < 0.05).

Conclusions

Short-term elevations in PM_2.5 concentrations may be associated with exacerbations in psoriasis. Further work is warranted to confirm the findings and elucidate the underlying biological mechanisms.

Allergy from perspective of environmental pollution effects: from an aspect of atopic dermatitis, immune system, and atmospheric hazards-a narrative review of current evidences

Environmental pollution has become more diversified in recent years as technologies for urbanization is increasingly more advanced. Several environmental factors such as air and water pollutants have been linked to allergic symptoms. For instance, because of industrialization for city development in many countries, polluted soil or tiny particles in the air could result in an even more hazardous environment for people to reside. Aside from the aspects of environmental issues, other newly emerging factors such as the electromagnetic field (EMF) also require further investigation. Here, in this narrative review, we focused on allergens from atmospheric and water pollution, hygiene improvement, changes in food trend, and residential environmental pollution. Current evidences regarding the association between various pollutants and the potential clinical diseases could be induced. For people with high skin exposure to air pollutants such as PM 2.5, PM 10, or sulfur dioxide, potential onset of dermatological allergic events should be alerted. The mechanisms involved in allergic diseases are being discussed and summarized. Interactions between immunological mechanisms and clinical implications could potentially provide clearer view to the association between allergic status and pollutants. Moreover, understanding the mechanistic role of allergens can raise awareness to global environment and public health.

Preventative Effects of Antioxidants against PM10 on Serum IgE Concentration, Mast Cell Counts, Inflammatory Cytokines, and Keratinocyte Differentiation Markers in DNCB-Induced Atopic Dermatitis Mouse Model

Particulate matter (PM) can cause oxidative stress, inflammation, and skin aging. We investigated the effects of antioxidants such as dieckol, punicalagin, epigallocatechin gallate (EGCG), resveratrol, and Siegesbeckiae Herba extract (SHE) against PM < 10 μm (PM10) on serum IgE concentration, mast cell counts, inflammatory cytokines, and keratinocyte differentiation markers in a 2,4-Dinitrochlorobenzene (DNCB)-induced atopic dermatitis mouse model. Seven-week-old BALB/c mice were sensitized with 2% DNCB. Atopic dermatitis-like lesions were induced on the mice with 0.2% DNCB. Antioxidants and PM10 were applied to the mice for 4 weeks. PM10 increased the serum IgE concentration and spleen weight in mice, and all antioxidants downregulated these parameters. Histological examination showed an increase in epidermal thickness and mast cell counts in response to PM10, and all antioxidants showed a decrease. PM10 upregulates the expression of inflammatory cytokines, including interleukin (IL)-1β, IL-4, IL-6, IL-17α, IL-25, IL-31 and thymic stromal lymphopoietin (TSLP) in mice, and all antioxidants inhibited the upregulation of inflammatory cytokines. ELISA showed the same results as real-time PCR. PM10 downregulates the expression of keratinocyte differentiation markers, including loricrin and filaggrin, in mouse keratinocytes and antioxidants prevented the downregulation of the keratinocyte differentiation markers. Conclusively, PM10 aggravated the DNCB-induced mouse model in serum IgE concentration, mast cell counts, inflammatory cytokine, and keratinocyte differentiation markers. In addition, antioxidants modulated changes in the DNCB-induced mouse model caused by PM10.

Association Between Short-term Exposure to Environmental Air Pollution and Psoriasis Flare

IMPORTANCE

Psoriasis is a chronic inflammatory disease with a relapsing-remitting course. Selected environmental factors such as infections, stressful life events, or drugs may trigger disease flares. Whether air pollution could trigger psoriasis flares is still unknown.

OBJECTIVE

To investigate whether short-term exposure to environmental air pollution is associated with psoriasis flares.

DESIGN, SETTING, AND PARTICIPANTS

This observational study with both case-crossover and cross-sectional design retrospectively analyzed longitudinal data from September 2013 to January 2020 from patients with chronic plaque psoriasis consecutively attending the outpatient dermatologic clinic of the University Hospital of Verona. For the case-crossover analysis, patients were included who had at least 1 disease flare, defined as Psoriasis Area and Severity Index (PASI) increase of 5 or greater between 2 consecutive assessments in a time frame of 3 to 4 months. For the cross-sectional analysis, patients were included who received any systemic treatment for 6 or more months, with grade 2 or higher consecutive PASI assessment.

MAIN OUTCOMES AND MEASURES

We compared the mean and cumulative (area under the curve) concentrations of several air pollutants (carbon monoxide, nitrogen dioxide, other nitrogen oxides, benzene, coarse particulate matter [PM; 2.5-10.0 μm in diameter, PM10] and fine PM [<2.5 μm in diameter, PM2.5]) in the 60 days preceding the psoriasis flare and the control visits.

RESULTS

A total of 957 patients with plaque psoriasis with 4398 follow-up visits were included in the study. Patients had a mean (SD) age of 61 (15) years and 602 (62.9%) were men. More than 15 000 measurements of air pollutant concentration from the official, open-source bulletin of the Italian Institute for Environmental Protection and Research (ISPRA) were retrieved. Among the overall cohort, 369 (38.6%) patients with psoriasis flare were included in the case-crossover study. We found that concentrations of all pollutants were significantly higher in the 60 days before psoriasis flare (median PASI at the flare 12; IQR, 9-18) compared with the control visit (median PASI 1; IQR, 1-3, P < .001). In the cross-sectional analysis, exposure to mean PM10 over 20 μg/m3 and mean PM2.5 over 15 μg/m3 in the 60 days before assessment were associated with a higher risk of PASI 5 or greater point worsening (adjusted odds ratio [aOR], 1.55; 95% CI, 1.21-1.99; and aOR, 1.25; 95% CI, 1.0-1.57, respectively). Sensitivity analyses that stratified for trimester of evaluation, with various lag of exposure and adjusting for type of treatment, yielded similar results.

CONCLUSIONS AND RELEVANCE

The findings of this case-crossover and cross-sectional study suggest that air pollution may be a trigger factor for psoriasis flare.

Short-term exposure of PM2.5 and PM10 increases the number of outpatients with eczema in Guangzhou: A time-series study

Background

The worldwide prevalence of eczema has continued to rise over the past decades. This has led to the emphasis on the association between air pollution and eczema. This study investigated the relationship between daily exposure to air pollution and the number of eczema outpatient visits in Guangzhou with the overarching goal of providing novel insights on the interventions for eczema aggravation and prevention.

Methods

Daily air pollution data, meteorological data, and the number of eczema outpatients were obtained from 18 January 2013 to 31 December 2018 in Guangzhou. A generalized additive model with Poisson distribution was used to assess the association between the number of eczema outpatient visits and short-term exposure to PM_2.5 and PM₁₀. In addition, the association of PM_2.5 and PM₁₀ by age (<65 years, ≥65 years) and gender was evaluated.

Results

A total of 293,343 eczema outpatient visits were recorded. The obtained results indicated that a 10 μg/m³ increase of the same day/lag 1 day/lag 2 days PM_2.5 was associated with increments of 2.33%, 1.81%, and 0.95% in eczema outpatient risk, respectively. On the other hand, a 10 μg/m³ increase of PM₁₀ was associated with eczema outpatients risk increments of 1.97%, 1.65%, and 0.98% respectively. Furthermore, the associations of PM on the increment of eczema were similar in the male and female groups. Results obtained after age stratified analyses indicated that the strongest positive association between PM_2.5 exposure and eczema was observed at lag 0 day with the percent changes being 4.72% and 3.34% in <12 years old, ≥12 and <65 years old, and ≥65 years old groups, respectively.

Conclusion

Short-term exposure to PM_2.5 and PM₁₀ increases the number of eczema outpatients, especially among children and the elderly. The relationship between air quality trends and hospital resource arrangement should be paid attention to by hospital managers which may aid in disease prevention and lower the health burden.

The Protective Effect of Hamamelis virginiana Stem and Leaf Extract on Fine Dust-Induced Damage on Human Keratinocytes

Witch hazel extracts have been used for decades as cosmetic ingredients in skin care products. Our present study aims to evaluate its potential in anti-pollution products using a previously reported in vitro model. Calcium is a universal second messenger, and we used human respiratory and skin cells to detect changes in intracellular Ca2+ concentrations upon particulate matter contact. Both an increase in pro-inflammatory markers and a decrease in tight junction proteins were confirmed, as previously reported. Witch hazel stem and leaf extract showed significant attenuation of Ca2+ response upon the challenge; it displayed systematic regulations of the signal generator, PAR-2; a pro-inflammatory marker, NF-κB; and a tight junction protein, Occludin. We identified hexagalloylglucose from the extract and concluded that it is a major component regulating protection from particulate matter. Based on these results, witch hazel extract containing hexagalloylglucose is an active ingredient in anti-pollution skin care products.