The effects of microbial materials adhered to Asian sand dust on allergic lung inflammation

Dust particulate matter increases pulmonary embolism onset: A nationwide time-stratified case-crossover study in China

BACKGROUND

Particulate matter (PM) has been found to elevate the risk of pulmonary embolism (PE) onset. Among the contributors to PM, dust PM stands as the second natural source, and its emissions are escalating due to climate change. Despite this, information on the effect of dust PM on PE onset is scarce. Hence, this study aims to investigate the impacts of dust PM10, dust PM2.5-10, and dust PM2.5 on PE onset.

METHODS

A nationwide time-stratified case-crossover study was conducted between 2015 and 2020, using data from 18,616 PE onset cases across 1,921 hospitals in China. The analysis employed a conditional logistic regression model to quantify the associations between dust PM10, dust PM2.5-10, and dust PM2.5 and PE onset. Furthermore, the study explored the time-distributed lag pattern of the effect of dust PM on PE development. Stratified analyses were performed based on sex, age, region, and season.

RESULTS

Dust PM10, dust PM2.5-10, and dust PM2.5 exhibited significant health effects on PE onset, particularly concerning exposure on the same day. The peak estimates were observed at lag 01 day, with the odds ratio being 1.011 [95 % confidence interval (CI): 1.003, 1.019], 1.014 (95 % CI: 1.003, 1.026), and 1.039 (95 % CI: 1.011, 1.068), for a 10 μg/m3 increase in the concentration of dust PM10, dust PM2.5-10, and dust PM2.5, respectively. In addition, the study identified a higher risk of PE onset associated with dust PM exposure during the warm season than that in cool season, particularly for dust PM2.5.

CONCLUSIONS

The findings from this study suggest that short-term exposure to dust PM, particularly dust PM2.5, may trigger PE onset, posing a significant health threat. Implementing measures to mitigate dust PM emissions and protect patients with PE from dust PM exposure is imperative.

Mortality risks from a spectrum of causes associated with sand and dust storms in China

Sand and Dust Storms (SDS) pose considerable health risks worldwide. Previous studies only indicated risk of SDS on overall mortality. This nationwide multicenter time-series study aimed to examine SDS-associated mortality risks extensively. We analyzed 1,495,724 deaths and 2024 SDS events from 1 February to 31 May (2013-2018) in 214 Chinese counties. The excess mortality risks associated with SDS were 7.49% (95% CI: 3.12-12.05%), 5.40% (1.25-9.73%), 4.05% (0.41-7.83%), 3.45% (0.34-6.66%), 3.37% (0.28-6.55%), 3.33% (0.07-6.70%), 8.90% (4.96-12.98%), 12.51% (6.31-19.08%), and 11.55% (5.55-17.89%) for ischemic stroke, intracerebral hemorrhagic stroke, hypertensive heart disease, myocardial infarction, acute myocardial infarction, acute ischemic heart disease, respiratory disease, chronic lower respiratory disease, and chronic obstructive pulmonary disease (COPD), respectively. SDS had significantly added effects on ischemic stroke, chronic lower respiratory disease, and COPD mortality. Our results suggest the need to implement public health policy against SDS.

Dasatinib suppresses particulate-induced pyroptosis and acute lung inflammation

Background: Humans are constantly exposed to various industrial, environmental, and endogenous particulates that result in inflammatory diseases. After being engulfed by immune cells, viz. Macrophages, such particulates lead to phagolysosomal dysfunction, eventually inducing pyroptosis, a form of cell death accompanied by the release of inflammatory mediators, including members of the interleukin (IL)-1 family. Phagolysosomal dysfunction results in the activation of the nod-like receptor family pyrin domain containing 3 (NLRP3) inflammasome, an immune complex that induces pyroptosis upon exposure to various external stimuli. However, several particulates induce pyroptosis even if the NLRP3 inflammasome is inhibited; this indicates that such inhibition is not always effective in treating diseases induced by particulates. Therefore, discovery of drugs suppressing particulate-induced NLRP3-independent pyroptosis is warranted. Methods: We screened compounds that inhibit silica particle (SP)-induced cell death and release of IL-1α using RAW264.7 cells, which are incapable of NLRP3 inflammasome formation. The candidates were tested for their ability to suppress particulate-induced pyroptosis and phagolysosomal dysfunction using mouse primary macrophages and alleviate SP-induced NLRP3-independent lung inflammation. Results: Several Src family kinase inhibitors, including dasatinib, effectively suppressed SP-induced cell death and IL-1α release. Furthermore, dasatinib suppressed pyroptosis induced by other particulates but did not suppress that induced by non-particulates, such as adenosine triphosphate. Dasatinib reduced SP-induced phagolysosomal dysfunction without affecting phagocytosis of SPs. Moreover, dasatinib treatment strongly suppressed the increase in IL-1α levels and neutrophil counts in the lungs after intratracheal SP administration. Conclusion: Dasatinib suppresses particulate-induced pyroptosis and can be used to treat relevant inflammatory diseases.

The Interactive Effects between Drought and Air Pollutants on Children's Upper Respiratory Tract Infection: A Time-Series Analysis in Gansu, China

As a destructive and economic disaster in the world, drought shows an increasing trend under the continuous global climate change and adverse health effects have been reported. The interactive effects between drought and air pollutants, which may also be harmful to respiratory systems, remain to be discussed. We built the generalized additive model (GAM) and distributed lag nonlinear model (DLNM) to estimate the effects of drought and air pollutants on daily upper respiratory infections (URTI) outpatient visits among children under 6 in three cities of Gansu province. The Standardized Precipitation Index (SPI) based on monthly precipitation (SPI-1) was used as an indicator of drought. A non-stratified model was established to explore the interaction effect of SPI-1 and air pollutants. We illustrated the number of daily pediatric URTI outpatient visits increased with the decrease in SPI-1. The interactive effects between air pollutants and the number of daily pediatric URTIs were significant. According to the non-stratified model, we revealed highly polluted and drought environments had the most significant impact on URTI in children. The occurrence of drought and air pollutants increased URTI in children and exhibited a significant interactive effect.

Co-exposure of peptidoglycan and heat-inactivated Asian sand dust exacerbates ovalbumin-induced allergic airway inflammation in mice

AIMS

Asian sand dust (ASD) comprises soil particles, microorganisms, and various chemical components. We examined whether peptidoglycan (PGN), a structural cell wall component of Gram-positive bacteria, exacerbates ASD-induced allergic airway inflammation in mice.

METHODS

The ASD (median diameter ∼4 µm) used was a certified reference material from the National Institute for Environmental Studies in Japan, derived from Gobi Desert surface soil collected in 2011. BALB/c mice were intratracheally exposed to PGN, heat-inactivated ASD (H-ASD), and ovalbumin (OVA), individually and in combination. Twenty-four hours after the final intratracheal administration, bronchoalveolar lavage fluid (BALF) and serum samples were collected. Inflammatory cell count, cytokine levels in the BALF, OVA-specific immunoglobulin levels in the serum, and pathological changes in the lungs were analyzed.

RESULTS AND DISCUSSION

After OVA + PGN + H-ASD treatment, the number of eosinophils, neutrophils, and macrophages in the BALF and of eosinophils in the lung tissue was significantly higher than that after OVA + PGN or OVA + H-ASD treatment. Moreover, levels of chemokines and cytokines associated with eosinophil recruitment and activation were significantly higher in the BALF of this group than in that of the OVA + PGN group, and tended to be higher than those in the OVA + H-ASD group. Pathological changes in the lungs were most severe in mice treated with OVA + PGN + H-ASD.

CONCLUSIONS

Our results indicate that PGN is involved in the exacerbation of ASD-induced allergic airway inflammation in mice. Thus, inhalation of ASD containing Gram-positive bacteria may trigger allergic bronchial asthma.

Korean Red Ginseng and Ginsenoside Rg3 Suppress Asian Sand Dust-Induced Epithelial-Mesenchymal Transition in Nasal Epithelial Cells

Chronic rhinosinusitis (CRS) is characterized by chronic inflammation of the sinonasal mucosa with epithelial dedifferentiation toward the mesenchymal phenotype, known as the epithelial–mesenchymal transition (EMT). Asian sand dust (ASD) can induce nasal mucosal inflammation and cause the development of EMT. Korean red ginseng (KRG) and ginsenoside Rg3 have been used as traditional herbal medicines to treat various diseases. The aim of this study was to investigate their effect on ASD-induced EMT in nasal epithelial cells. Primary nasal epithelial cells were incubated with ASD with or without KRG or Rg3, and the production of transforming growth factor-β1 (TGF-β1) and interleukin (IL)-8 was measured. EMT markers were determined by RT-PCR, Western blot analysis, and confocal microscopy, and transcription factor expression by Western blot analysis. The effect on cell migration was evaluated using the wound scratch assay. Results showed ASD-induced TGF-β1 production, downregulation of E-cadherin, and upregulation of fibronectin in nasal epithelial cells. KRG and Rg3 suppressed TGF-β1 production (31.7% to 43.1%), upregulated the expression of E-cadherin (26.4% to 88.3% in mRNA), and downregulated that of fibronectin (14.2% to 46.2% in mRNA and 52.3% to 70.2% in protein). In addition, they suppressed the ASD-induced phosphorylation of ERK, p38, and mTOR, as well as inhibiting the ASD-induced migration of nasal epithelial cells (25.2% to 41.5%). The results of this study demonstrate that KRG and Rg3 inhibit ASD-induced EMT by suppressing the activation of ERK, p38, and mTOR signaling pathways in nasal epithelial cells.

Asian Sand Dust Particles Enhance the Development of Aspergillus fumigatus Biofilm on Nasal Epithelial Cells

Background: Asian sand dust (ASD) and Aspergillus fumigatus are known risk factors for airway mucosal inflammatory diseases. Bacterial and fungal biofilms commonly coexist in chronic rhinosinusitis and fungus balls. We evaluated the effects of ASD on the development of A. fumigatus biofilm formation on nasal epithelial cells. Methods: Primary nasal epithelial cells were cultured with A. fumigatus conidia with or without ASD for 72 h. The production of interleukin (IL)-6, IL-8, and transforming growth factor (TGF)-β1 from nasal epithelial cells was determined by the enzyme-linked immunosorbent assay. The effects of ASD on A. fumigatus biofilm formation were determined using crystal violet, concanavalin A, safranin staining, and confocal scanning laser microscopy. Results: ASD and A. fumigatus significantly enhanced the production of IL-6 and IL-8 from nasal epithelial cells. By coculturing A. fumigatus with ASD, the dry weight and safranin staining of the fungal biofilms significantly increased in a time-dependent manner. However, the increased level of crystal violet and concanavalin A stain decreased after 72 h of incubation. Conclusions: ASD and A. fumigatus induced the production of inflammatory chemical mediators from nasal epithelial cells. The exposure of A. fumigatus to ASD enhanced the formation of biofilms. The coexistence of ASD and A. fumigatus may increase the development of fungal biofilms and fungal inflammatory diseases in the sinonasal mucosa.

Mechanisms underlying the health effects of desert sand dust

Desertification and climate change indicate a future expansion of the global area of dry land and an increase in the risk of drought. Humans may therefore be at an ever-increasing risk of frequent exposure to, and resultant adverse health effects of desert sand dust. This review appraises a total of 52 experimental studies that have sought to identify mechanisms and intermediate endpoints underlying epidemiological evidence of an impact of desert dust on cardiovascular and respiratory health. Toxicological studies, in main using doses that reflect or at least approach real world exposures during a dust event, have demonstrated that virgin sand dust particles and dust storm particles sampled at remote locations away from the source induce inflammatory lung injury and aggravate allergen-induced nasal and pulmonary eosinophilia. Effects are orchestrated by cytokines, chemokines and antigen-specific immunoglobulin potentially via toll-like receptor/myeloid differentiation factor signaling pathways. Findings suggest that in addition to involvement of adhered chemical and biological pollutants, mineralogical components may also be implicated in the pathogenesis of human respiratory disorders during a dust event. Whilst comparisons with urban particulate matter less than 2.5 μm in diameter (PM2.5) suggest that allergic inflammatory responses are greater for microbial element-rich dust- PM2.5, aerosols generated during dust events appear to have a lower oxidative potential compared to combustion-generated PM2.5 sampled during non-dust periods. In vitro findings suggest that the significant amounts of suspended desert dust during storm periods may provide a platform to intermix with chemicals on its surfaces, thereby increasing the bioreactivity of PM2.5 during dust storm episodes, and that mineral dust surface reactions are an unrecognized source of toxic organic chemicals in the atmosphere, enhancing toxicity of aerosols in urban environments. In summary, the experimental research on desert dust on respiratory endpoints go some way in clarifying the mechanistic effects of atmospheric desert dust on the upper and lower human respiratory system. In doing so, they provide support for biological plausibility of epidemiological associations between this particulate air pollutant and events including exacerbation of asthma, hospitalization for respiratory infections and seasonal allergic rhinitis.

Respiratory and Systemic Toxicity of Inhaled Artificial Asian Sand Dust in Pigs

Air pollution, particularly caused by Asian sand dust (ASD) and particulate matter (PM), has become one of the leading threats to public health. However, the majority of studies have primarily focused on epidemiological assessment, and in vivo toxicities of certain air pollutants have been poorly elucidated in medium/large-size laboratory animals. To investigate the impact of ASD in domestic animals, 16 Landrace pigs were exposed to an artificial ASD sandstorm for 6 h. All animals were divided in four cages, and a commercial yellow soil was used for generating artificial mineralogical particles. Blood samples were collected, and necropsies were performed before exposure and 6, 12, 24, and 72 h after exposure. Complete blood cell count and the levels of serum biochemical enzymes, blood gas, electrolytes, and a variety of inflammatory cytokines were evaluated. In addition, histopathological examination was conducted. Various test results proved acute lower airway disorders with systemic inflammation in pigs. To our knowledge, this study is the first to describe experimental research in domestic animals concerning the damage caused by artificial ASD exposure. The results of this study suggest that ASD has importance in terms of not only public health but also of ultimate economic losses in the pork industry.

Association between sum of volatile organic compounds and occurrence of building-related symptoms in humans: A study in real full-scale laboratory houses

It is well known that the indoor environment, particularly indoor air quality (IAQ), has significant effects on building-related symptoms (BRSs) in humans, such as irritation of mucosal membranes, headaches, and allergies, such as asthma and atopic dermatitis. In 2017, Chiba University launched the "Chemiless Town Project Phase 3" to investigate the relationship between IAQ and human health. Two laboratory houses (LHs) were built on a university campus in which the interiors and exteriors were similar, but the levels of indoor air volatile organic compounds (VOCs) were different. A total of 141 participants evaluated IAQ using their sensory perception. There was a significant relationship between differences in VOC levels and BRSs occurrence (OR: 6.89, 95% CI: 1.40-33.98). It was suggested that people with a medical history of allergies (OR: 5.73, 95% CI: 1.12-29.32) and those with a high sensitivity to chemicals (OR: 8.82, 95% CI: 1.16-67.16) tended to experience BRSs. Thus, when buildings are constructed, people with a history of allergies or with a sensitivity to chemicals may be at high risk to BRSs, and it is important to pay attention to IAQ to prevent BRSs.

Association of short term exposure to Asian dust with increased blood pressure

Air pollution causes hypertension, cardiovascular disease, and mortality. Asian dust (AD) reportedly induces asthma or acute myocardial infarction along with air pollution, but its impact on blood pressure (BP) is unknown. We investigated the association between short-term AD exposure and BP fluctuations in 300,952 individuals whose BP was measured during April 2005–March 2015 and divided them into AD and non-AD groups based on visitation for AD-related events. AD’s occurrence, air pollutants’ concentration (suspended particulate matter, SO₂, NO₂, photochemical oxidants), and meteorological variables (mean ambient temperature, relative humidity) were obtained from a monitoring station; AD events correlated with decreased visibility (< 10 km). We observed 61 AD days, with 3897 participants undergoing medical check-ups. Short-term AD exposure at lag day-0 was significantly associated with higher systolic BP (SBP), diastolic BP (DBP), and pulse rate (PR) risk (β = 1.85, 95% confidence interval (CI) 1.35–2.35 for SBP, β = 2.24, 95% CI 1.88–2.61 for DBP, β = 0.52, 95% CI 0.14–0.91 for PR) using multi-pollutant model. Population-attributable fractions exposed to AD were 11.5% for those with elevated SBP (SBP ≥ 120 mmHg) and 23.7% for those with hypertension (SBP ≥ 140 mmHg or DBP ≥ 90 mmHg). This study showed a strong association between short-term AD exposure and increased SBP and DBP.

Critical role of IL-33, but not IL-25 or TSLP, in silica crystal-mediated exacerbation of allergic airway eosinophilia

Silica crystals (silica), which are a major mineral component of volcanic ash and desert dust, contribute to the pathogenesis of pulmonary disorders such as asthma and fibrosis. Although administration of silica or sand dust to rodents exacerbates development of ovalbumin-induced or house dust mite-induced asthma-like airway inflammation, the detailed mechanisms remain unclear. Here, using murine models, we found that silica can induce IL-33 expression in pulmonary epithelial cells. IL-33, but not IL-25 or TSLP, and type 2 cytokines such as IL-5 and IL-13 were critically involved in silica's exacerbation of OVA-induced airway eosinophilia in mice. Innate lymphoid cells (ILCs), but not T, B or NKT cells, were also involved in the setting. Moreover, a scavenger receptor that recognized silica was important for silica's exacerbating effect. These observations suggest that IL-33 induced in epithelial cells by silica activates ILCs to produce IL-5 and/or IL-13, contributing to silica's exacerbation of OVA-induced airway eosinophilia in mice. Our findings provide new insight into the underlying mechanisms of exacerbation of pulmonary disorders such as asthma following inhalation of silica-containing materials such as volcanic ash and desert dust.

Global nature of airborne particle toxicity and health effects: a focus on megacities, wildfires, dust storms and residential biomass burning

Since air pollutants are difficult and expensive to control, a strong scientific underpinning to policies is needed to guide mitigation aimed at reducing the current burden on public health. Much of the evidence concerning hazard identification and risk quantification related to air pollution comes from epidemiological studies. This must be reinforced with mechanistic confirmation to infer causality. In this review we focus on data generated from four contrasting sources of particulate air pollution that result in high population exposures and thus where there remains an unmet need to protect health: urban air pollution in developing megacities, household biomass combustion, wildfires and desert dust storms. Taking each in turn, appropriate measures to protect populations will involve advocating smart cities and addressing economic and behavioural barriers to sustained adoption of clean stoves and fuels. Like all natural hazards, wildfires and dust storms are a feature of the landscape that cannot be removed. However, many efforts from emission containment (land/fire management practices), exposure avoidance and identifying susceptible populations can be taken to prepare for air pollution episodes and ensure people are out of harm's way when conditions are life-threatening. Communities residing in areas affected by unhealthy concentrations of any airborne particles will benefit from optimum communication via public awareness campaigns, designed to empower people to modify behaviour in a way that improves their health as well as the quality of the air they breathe.

Health Effects of Asian Dust: A Systematic Review and Meta-Analysis

BACKGROUND

Potential adverse health effects of Asian dust exposure have been reported, but systematic reviews and quantitative syntheses are lacking.

OBJECTIVE

We reviewed epidemiologic studies that assessed the risk of mortality, hospital admissions, and symptoms/dysfunction associated with exposure to Asian dust.

METHODS

We performed a systematic search of PubMed and Web of Science to identify studies that reported the association between Asian dust exposure and human health outcomes. We conducted separate meta-analyses using a random-effects model for mortality and hospital admissions for a specific health outcome and assessed pooled estimates for each lag when at least three studies were available for a specific lag.

RESULTS

We identified 89 studies that met our inclusion criteria for the systematic review, and 21 studies were included in the meta-analysis. The pooled estimates (percentage changes) of mortality from circulatory and respiratory causes for Asian dust days vs. non-Asian dust days were 2.33% [95% confidence interval (CI): 0.76, 3.93] increase at lag 0 and 3.99% (95% CI: 0.08, 8.06) increase at lag 3, respectively. The increased risk for hospital admissions for respiratory disease, asthma, and pneumonia peaked at lag 3 by 8.85% (95% CI: 0.80, 17.55), 14.55% (95% CI: 6.74, 22.94), and 8.51% (95% CI: 2.89, 14.44), respectively. Seven of 12 studies reported reduced peak expiratory flow, and 16 of 21 studies reported increased respiratory symptoms associated with Asian dust exposure. There were substantial variations between the studies in definitions of Asian dust, study designs, model specifications, and confounder controls.

DISCUSSION

We found evidence of increased mortality and hospital admissions for circulatory and respiratory events. However, the number of studies included in the meta-analysis was not large and further evidences are merited to strengthen our conclusions. Standardized protocols for epidemiological studies would facilitate interstudy comparisons. https://doi.org/10.1289/EHP5312.

Association between Asian dust exposure and respiratory function in children with bronchial asthma in Nagasaki Prefecture, Japan

BACKGROUND

Studies on the adverse effects of Asian dust (AD) on respiratory function in children are scarce. The objective of this study was to examine the association between AD and respiratory function by measuring peak expiratory flow rates (PEFRs) in asthmatic children.

METHODS

The study was carried out from March to May from 2014 through 2016. One hundred ten children with bronchial asthma were recruited from four hospitals in the Goto Islands and south Nagasaki area in Nagasaki prefecture. The parents were asked to record their children's PEFRs every morning/evening and clinical symptoms in an asthma diary. AD was assessed from light detection and ranging data, and a linear mixed-effects model was used to estimate the effects of AD on daily PEFR. Time-stratified case-crossover analyses were performed to examine the association between AD and asthma attacks defined by reduction levels in PEFR.

RESULTS

AD was detected on 11 days in the Goto Islands, and on 23 days in the south Nagasaki area. After adjusting for age, sex, temperature, and daily oxidants, we found a consistent association between AD and a 1.1% to 1.7% decrease in PEFR in the mornings and a 0.7% to 1.3% decrease in the evenings at a lag of 0 to 5 days. AD was not associated with the number of asthma attacks, respiratory symptoms, or other symptoms at any lag days examined.

CONCLUSIONS

Exposure to AD was associated with reduced PEFR, although the effects were not large enough to induce clinically apparent symptoms, in clinically well-controlled asthmatic children.

Association of short-term exposure to air pollution with myocardial infarction with and without obstructive coronary artery disease

Background

Air pollution including particulate matter with an aerodynamic diameter ≤2.5 µm (PM2.5) increases the risk of acute myocardial infarction. However, whether short-term exposure to PM2.5 triggers the onset of myocardial infarction with nonobstructive coronary arteries, compared with myocardial infarction with coronary artery disease, has not been elucidated. This study aimed to estimate the association between short-term exposure to PM2.5 and admission for acute myocardial infarction, myocardial infarction with coronary artery disease, and myocardial infarction with nonobstructive coronary arteries.

Design

This was a time-stratified case-crossover study and multicenter validation study.

Methods

This study used a nationwide administrative database in Japan between April 2012–March 2016. Of 137,678 acute myocardial infarction cases, 123,633 myocardial infarction with coronary artery disease and 14,045 myocardial infarction with nonobstructive coronary arteries were identified by a validated algorithm combined with International Classification of Disease (10th revision), diagnostic, and procedure codes. Air pollutants and meteorological data were obtained from the monitoring station nearest to the admitting hospital.

Results

In spring (March–May), the short-term increase of 10 µg/m3 in PM2.5 2 days before admission was significantly associated with admission for acute myocardial infarction, myocardial infarction with nonobstructive coronary arteries, and myocardial infarction with coronary artery disease after adjustment for meteorological variables (odds ratio 1.060, 95% confidence interval 1.038–1.082; odds ratio 1.151, 1.079–1.227; odds ratio 1.049, 1.026–1.073, respectively), while the association was not significant in other variables. These associations were also observed after adjustment for other co-pollutants. The risk for myocardial infarction with nonobstructive coronary arteries (vs myocardial infarction with coronary artery disease) was associated with an even lower concentration of PM2.5 under the current environmental standards.

Conclusions

This study showed the seasonal difference of acute myocardial infarction risk attributable to PM2.5 and the difference in the threshold of triggering the onset of acute myocardial infarction subtype.

Short-term exposure to desert dust and the risk of acute myocardial infarction in Japan: a time-stratified case-crossover study

Particulate matter from natural sources such as desert dust causes harmful effects for health. Asian dust (AD) increases the risk of acute myocardial infarction (AMI). However, little is known about the risk of myocardial infarction with nonobstructive coronary arteries (MINOCA), compared to myocardial infarction with coronary artery disease (MI-CAD). Using a time-stratified case-crossover design and conditional logistic regression models, the association between short-term exposure to AD whereby decreased visibility (< 10 km) observed at each monitoring station nearest to the hospitals was used for exposure measurements and admission for AMI in the spring was investigated using a nationwide administrative database between April 2012 and March 2016. According to presence of revascularization and coronary atherosclerosis, AMI patients (n = 30,435) were divided into 2 subtypes: MI-CAD (n = 27,202) or MINOCA (n = 3233). The single lag day-2 was used in AD exposure based on the lag effect analysis. The average level of meteorological variables and co-pollutants on the 3 days prior to the case/control days were used as covariates. The occurrence of AD events 2 days before the admission was associated with admission for MINOCA after adjustment for meteorological variables [odds ratio 1.65; 95% confidence interval (CI) 1.18-2.29], while the association was not observed in MI-CAD. The absolute risk difference of MINOCA admission was 1.79 (95% CI 1.21-2.38) per 100,000 person-year. These associations between AD exposure and the admission for MINOCA remained unchanged in two-pollutant models. This study provides evidence that short-term exposure to AD is associated with a higher risk of MINOCA, but not MI-CAD.

Asian Sand Dust Upregulates IL-6 and IL-8 via ROS, JNK, ERK, and CREB Signaling in Human Nasal Fibroblasts

Background

Asian sand dust (ASD) profoundly affects respiratory health by inducing inflammation and causing upper airway inflammatory diseases. Interleukin (IL)-6 and IL-8 are pro-inflammatory mediators that are involved in upper airway inflammatory diseases. However, the effect of ASD on the production of IL-6 and IL-8 in nasal fibroblasts has not been adequately studied. We investigated the effect of ASD on the induction of pro-inflammatory mediators and its underlying mechanisms in nasal fibroblasts.

Methods

Real-time cytotoxicity assays were used to determine the effect of ASD on the viability of fibroblasts. Enzyme-linked immunosorbent assays and real-time polymerase chain reactions were performed to determine whether ASD induced the expression of IL-6 and IL-8. Reactive oxygen species (ROS) were quantified using 2, 7-dichlorofluorescein-diacetate and MitoSOX Red. Induction of IL-6 and IL-8 signal transduction pathways by ASD was confirmed by Western blotting. Ex vivo culture of the inferior turbinate tissue was performed to confirm the effects of ASD.

Results

ASD upregulated ROS levels, and this in turn promoted IL-6 and IL-8 expression through the MAPK (JNK and ERK) and CREB signaling pathways in nasal fibroblasts. However, ASD did not induce phosphorylation of p38. Specific inhibitors of each pathway (ROS, JNK, ERK, and CREB inhibitors) suppressed ASD-induced IL-6 and IL-8 upregulation.

Conclusions

ASD induces pro-inflammatory mediators, and the increased levels of IL-6 and IL-8 might be associated with the pathogenesis of chronic rhinosinusitis.

Exposure to Asian dust within a few days of delivery is associated with placental abruption in Japan: a case-crossover study

OBJECTIVE

Asian dust is a natural phenomenon in which dust particles are transported from desert areas in China and Mongolia to East Asia. Short-term exposure to Asian dust has been associated with cardiovascular disease through mechanisms such as systemic inflammation. Because inflammation is a potential trigger of placental abruption, exposure may also lead to abruption. We examined whether exposure to Asian dust was associated with abruption.

DESIGN

A bi-directional, time-stratified case-crossover design.

SETTING AND POPULATION

From the Japan Perinatal Registry Network database, we identified 3014 patients who delivered singleton births in hospitals in nine Japanese prefectures from 2009 to 2014 with a diagnosis of placental abruption.

METHODS

Asian dust levels were measured at Light Detection and Ranging monitoring stations, and these measurements were used to define the Asian dust days. As there was no information on the onset day of abruption, we assumed this day was the day before delivery (lag1).

MAIN OUTCOME MEASURES

Placental abruption.

RESULTS

During the study period, the Asian dust days ranged from 15 to 71 days, depending on the prefecture. The adjusted odds ratio of placental abruption associated with exposure to Asian dust was 1.4 (95% confidence interval = 1.0, 2.0) for cumulative lags of 1-2 days. Even after adjustment for co-pollutant exposures, this association did not change substantially.

CONCLUSIONS

In this Japanese multi-area study, exposure to Asian dust was associated with an increased risk of placental abruption.

TWEETABLE ABSTRACT

Exposure to environmental factors such as Asian dust may be a trigger of placental abruption.

Effect of exposure to Asian sand dust-Particulate matter on liver Tenascin-C expression in human cancer cell and mouse hepatic tissue

Asian Sand Dust-Particulate Matter (ASD-PM) aerosol brings large amounts of wind-eroded soil particles containing high concentrations of metallic components caused by industrialization and vehicles. Proinflammatory and cytotoxic cytokines trigger local inflammatory responses and cause a systematically high incidence of cardiovascular and other diseases. Tenascin C (Tn-C) is known to be expressed in damaged tissue or in a developmental stage of tissue. In this study, we examined the expression of Tn-C and Fibronectin in human cancer-cell lines and in liver tissue of mice treated with ASD-PM to investigate the inflammatory and cell-damage effects of ASD-PM. In our in vivo study, mice were intratracheally instilled with saline suspensions of ASD-PM particles. Instillation of these particles was repeated twice a week for 12 weeks and the liver tissues were stained with hematoxylin, eosin, and Masson's trichrome, and we carried out an IF. Tn-C expression in liver tissues was detected by RT-PCR and western blot analysis. In the results, the expression of Tn-C increased in a dose-dependent manner in both RNA and Immunofluorescence assay (IF). In our in vitro study, A549 and Hep3B cell lines were incubated in culture media with Transforming Growth Factor-Beta1(TGF-β1) and ASD-PM. Immunofluorescence microscopy images showed a two times stronger expression of fluorescence in the ASD-treated group than in that treated with TGF-β1. They also showed a stronger expression of Tn-C in proportion to the concentration of ASD-PM. We confirmed that ASD-PM when inhaled formally migrated to other organs and induced Tn-C expression. ASD-PM containing metals causes expression of Tn-C in liver tissue in proportion to the concentration of ASD-PM.

Dithiothreitol-Measured Oxidative Potential of Size-Segregated Particulate Matter in Fukuoka, Japan: Effects of Asian Dust Events

Oxidative potential is an important property of particulate matter (PM) that has been regarded as a more health-relevant metric than PM mass. We investigated the oxidative potential of size-segregated PM and effects of Asian dust events in Fukuoka, western Japan. Aerosol particles with diameters smaller and larger than 2.5 μm (fine and coarse particles, respectively) were collected continually from 16 March through 26 May 2016. The oxidative potential was analyzed using dithiothreitol (DTT) assay; chemical components of PM were also found. Air-volume normalized oxidative potential quantified by DTT assay (DTT_v) was significantly higher during Asian dust events than during nondust-event days. The mean DTT_v of fine and coarse particles during Asian dust events were, respectively, 1.5 and 2.7 times higher than that during nonevent days. DTT_v of fine particles was highly correlated with elements dominated by anthropogenic combustion sources and with the elements emitted from multiple sources including mineral dust and combustion sources. DTT_v of coarse particles strongly correlated with the mineral dust derived elements, suggesting concentration of mineral dust particles as an important controlling factor especially for the oxidative potential of the coarse particles. We estimated the contributions of water-soluble transition metals to the oxidative potential of PM. Water-soluble transition metals (mainly Cu and Mn) can explain only approximately 37% and 60% of the measured oxidative potential of fine and coarse particles, respectively, suggesting substantial contributions of aerosol components other than water-soluble transition metals such as quinones and insoluble minerals.

Effects of co-exposure of lipopolysaccharide and β-glucan (Zymosan A) in exacerbating murine allergic asthma associated with Asian sand dust

During the 2000s, Asian sand dust (ASD) was implicated in the increasing prevalence of respiratory disorders, including asthma. We previously demonstrated that a fungus from ASD aerosol exacerbated ovalbumin (OVA)-induced airways inflammation. Exposure to heat-inactivated ASD (H-ASD) and either Zymosan A (ZymA, containing β-glucan) or lipopolysaccharide (LPS) exacerbated allergic airways inflammation in a mouse model, but the effects of co-exposure of LPS and β-glucan are unclear. We investigated the effects of co-exposure of LPS and ZymA in OVA-induced allergic airways inflammation with ASD using BALB/c mice. Exposure to OVA + LPS enhanced the recruitment of inflammatory cells to the lungs, particularly neutrophils; exposure to OVA + LPS + H-ASD potentiated this effect. Exposure to OVA + ZymA + H-ASD stimulated the recruitment of inflammatory cells to the lungs, particularly eosinophils, and serum levels of OVA-specific IgE and IgG1 antibodies, whereas exposure to OVA + ZymA did not affect most indicators of lung inflammation. Although exposure to OVA + LPS + ZymA + H-ASD affected a few allergic parameters additively or synergistically, most allergic parameters in this group indicated the same level of exposure to OVA + LPS + H-ASD or OVA + ZymA + H-ASD. These results suggest that LPS and ZymA play different roles in allergic airways inflammation with ASD; LPS mainly enhances neutrophil recruitment through H-ASD, and ZymA enhances eosinophil recruitment through H-ASD.

The position paper of the Polish Society of Allergology on climate changes, natural disasters and allergy and asthma

The observed global climate change is an indisputable cause of the increased frequency of extreme weather events and related natural disasters. This phenomenon is observed all over the world including Poland. Moreover, Polish citizens as tourists are also exposed to climate phenomena that do not occur in our climate zone. Extreme weather events and related disasters can have a significant impact on people with allergic diseases, including asthma. These effects may be associated with the exposure to air pollution, allergens, and specific microclimate conditions. Under the auspices of the Polish Society of Allergology, experts in the field of environmental allergy prepared a statement on climate changes, natural disasters and allergy and asthma to reduce the risk of adverse health events provoked by climate and weather factors. The guidelines contain the description of the factors related to climate changes and natural disasters affecting the course of allergic diseases, the specific microclimate conditions and the recommendations of the Polish Society of Allergology for vulnerable population, patients suffering from asthma and allergy diseases, allergologists and authorities in the event of climate and weather hazards.

Asian dust exposure triggers acute myocardial infarction

Aims

To elucidate whether Asian dust is associated with the incidence of acute myocardial infarction (AMI) and to clarify whether patients who are highly sensitive to Asian dust will develop AMI.

Methods and results

Twenty-one participating institutions located throughout Kumamoto Prefecture and capable of performing coronary intervention were included in the study. Data for ground-level observations of Asian dust events were measured at the Kumamoto Local Meteorological Observatory. Data collected between 1 April 2010 and 31 March 2015 were analysed, and 3713 consecutive AMI patients were included. A time-stratified case-crossover design was applied to examine the association between Asian dust exposure and AMI. The occurrence of Asian dust events at 1 day before the onset of AMI was associated with the incidence of AMI [odds ratio (OR), 1.46; 95% confidence interval (CI), 1.09-1.95] and especially, non-ST-segment elevation myocardial infarction was significant (OR 2.03; 95% CI, 1.30-3.15). A significant association between AMI and Asian dust was observed in patients with age ≥75 years, male sex, hypertension, diabetes mellitus, never-smoking status, and chronic kidney disease (CKD). However, Asian dust events had a great impact on AMI onset in patients with CKD (P < 0.01). A scoring system accounting for several AMI risk factors was developed. The occurrence of Asian dust events was found to be significantly associated with AMI incidence among patients with a risk score of 5-6 (OR 2.45; 95% CI: 1.14-5.27).

Conclusion

Asian dust events may lead to AMI and have a great impact on its onset in patients with CKD.

Development of electrochemical biosensor for detection of pathogenic microorganism in Asian dust events

We developed a single-walled carbon nanotubes (SWCNTs)-based electrochemical biosensor for the detection of Bacillus subtilis, one of the microorganisms observed in Asian dust events, which causes respiratory diseases such as asthma and pneumonia. SWCNTs plays the role of a transducer in biological antigen/antibody reaction for the electrical signal while 1-pyrenebutanoic acid succinimidyl ester (1-PBSE) and ant-B. subtilis were performed as a chemical linker and an acceptor, respectively, for the adhesion of target microorganism in the developed biosensor. The detection range (10²-10¹⁰ CFU/mL) and the detection limit (10² CFU/mL) of the developed biosensor were identified while the response time was 10 min. The amount of target B. subtilis was the highest in the specificity test of the developed biosensor, compared with the other tested microorganisms (Staphylococcus aureus, Flavobacterium psychrolimnae, and Aquabacterium commune). In addition, target B. subtilis detected by the developed biosensor was observed by scanning electron microscope (SEM) analysis.

Dust particles-induced intracellular Ca2+ signaling and reactive oxygen species in lung fibroblast cell line MRC5

Epidemiologic interest in particulate matter (PM) is growing particularly because of its impact of respiratory health. It has been elucidated that PM evoked inflammatory signal in pulmonary epithelia. However, it has not been established Ca²⁺ signaling mechanisms involved in acute PM-derived signaling in pulmonary fibroblasts. In the present study, we explored dust particles PM modulated intracellular Ca²⁺ signaling and sought to provide a therapeutic strategy by antagonizing PM-induced intracellular Ca²⁺ signaling in human lung fibroblasts MRC5 cells. We demonstrated that PM10, less than 10 µm, induced intracellular Ca²⁺ signaling, which was mediated by extracellular Ca²⁺. The PM10-mediated intracellular Ca²⁺ signaling was attenuated by antioxidants, phospholipase blockers, polyADPR polymerase 1 inhibitor, and transient receptor potential melastatin 2 (TRPM2) inhibitors. In addition, PM-mediated increases in reactive oxygen species were attenuated by TRPM2 blockers, clotrimazole (CLZ) and N-(p-amylcinnamoyl) anthranilic acid (ACA). Our results showed that PM10 enhanced reactive oxygen species signal by measuring DCF fluorescence and the DCF signal attenuated by both TRPM2 blockers CLZ and ACA. Here, we suggest functional inhibition of TRPM2 channels as a potential therapeutic strategy for modulation of dust particle-mediated signaling and oxidative stress accompanying lung diseases.

Co-exposure to zymosan A and heat-inactivated Asian sand dust exacerbates ovalbumin-induced murine lung eosinophilia

Background

Epidemiological studies have implicated Asian sand dust (ASD) in the increased prevalence of respiratory disorders, including asthma. It has been observed that fungal elements such as β-glucan can be adsorbed onto ASD. In the present study, the exacerbating effect of the combined exposure to zymosan A (ZymA) containing yeast β-glucan and heat-inactivated ASD on ovalbumin (OVA)-induced murine lung eosinophilia was investigated.

Methods

BALB/c mice were repeatedly instilled intratracheally with one of eight immunogenic formulations consisting of various combinations of (1) ZymA, (2) ASD that was briefly heated to remove organic substances (H-ASD), and (3) OVA in normal saline, or each of the above alone. Pathologic changes, cytological alterations in bronchoalveolar lavage fluid (BALF), changes in inflammatory cytokines and chemokines in BALF, and OVA-specific IgE and IgG₁ antibodies in serum were investigated.

Results

Exposure to ZymA with or without OVA had no effect on most indicators of lung inflammation. Exposure to H-ASD with OVA increased the recruitment of inflammatory cells to the lungs and the serum levels of OVA-specific IgE and IgG₁. The combination OVA + ZymA + H-ASD induced a marked recruitment of eosinophils and upregulation of T helper 2 (Th2) cytokines (interleukin [IL]-4 and IL-13), IL-6, eotaxin/CCL11, and monocyte chemotactic protein (MCP)-3/CCL7 in BALF and OVA-specific IgE in serum. This treatment also induced the most severe pathological changes in the lungs of mice. ZymA was found to boost the effects of H-ASD, thereby exacerbating the OVA-induced allergic inflammation, even though ZymA alone did not have such effect.

Conclusions

The results suggest that fungal elements such as β-1,3-glucan aggravate the allergic inflammation caused by ASD. Our findings may facilitate prophylaxis of some allergic diseases in Asia.

Immunity-Related Protein Expression and Pathological Lung Damage in Mice Poststimulation with Ambient Particulate Matter from Live Bird Markets

The objective of this study was to obtain insight into the adverse health effects of airborne particulate matter (PM) collected from live bird markets and to determine whether biological material in PM accounts for immune-related inflammatory response. Mice were exposed to a single or repeated dose of PM, after which the expression of toll-like receptors (TLRs), cytokines, and chemokines in the lungs of infected mice were examined by enzyme-linked immunosorbent assay and histopathological analysis. Results after single and repeated PM stimulation with PM2.5+,PM2.5−,PM10+, and PM10− indicated that TLR2 and TLR4 played a dominant role in the inflammatory responses of the lung. Further analysis demonstrated that the expression levels of IL-1β, TNF-α, IFN-γ, IL-8, IP-10, and MCP-1 increased significantly, which could eventually contribute to lung injury. Moreover, biological components in PM were critical in mediating immune-related inflammatory responses and should therefore not be overlooked.

The Effect of Seasonal Variations in Airborne Particulate Matter on Asthma-Related Airway Inflammation in Mice

This study aimed to investigate the effects of winter and spring particulate matter (PM) on airway inflammation and allergies in a mouse asthma model. PM was collected during 7–28 February 2013 (winter) and during 7–28 April 2013 (spring) in Yonago, Japan. NC/Nga mice were co-sensitized using intranasal instillation of the PMs and Dermatophagoides farinae (Df) for 5 consecutive days, and were subsequently challenged using intranasal Df at 7 days after the last sensitization. At 24 h after the challenge, serum immunoglobulin levels, differential leukocyte counts, and inflammatory cytokines levels were measured in the mice’s bronchoalveolar lavage fluid (BALF). Compared to co-sensitization using spring PM and Df, winter PM and Df induced greater increases in the BALF neutrophil and eosinophil counts and total serum IgE and IgG2a levels. Furthermore, winter PM-sensitized mice exhibited higher BALF levels of interleukin-5, interleukin-13, interleukin-6, and keratinocyte-derived chemokine. Therefore, we observed seasonal variations in the effects of PM on asthma-related airway inflammation. These findings suggest that the compositions of PM vary according to season, and that it is important to evaluate PM compositions in order to understand the associations between asthma and PM.

Asian Dust and Pediatric Emergency Department Visits Due to Bronchial Asthma and Respiratory Diseases in Nagasaki, Japan

Background

The adverse health effects of Asian dust (AD) on the respiratory system of children are unclear. We hypothesized that AD events may lead to increased visits by children to emergency medical centers due to bronchial asthma and respiratory diseases, including bronchial asthma.

Methods

We used anonymized data on children receiving primary emergency treatment at Nagasaki Municipal Primary Emergency Medical Center, Japan between March 2010 and September 2013. We used Light Detection and Ranging (LIDAR) data to assess AD exposure and performed time-stratified case-crossover analyses to examine the association between AD exposure and emergency department visits. The main analysis was done with data collected from March through May each year.

Results

The total number of emergency department visits during the study period was 756 for bronchial asthma and 5421 for respiratory diseases, and the number of “AD days” was 47. In school children, AD events at lag day 3 and lag day 4 were associated with increased emergency department visits due to bronchial asthma, with odds ratios of 1.837 (95% confidence interval [CI], 1.212–2.786) and 1.829 (95% CI, 1.179–2.806), respectively. AD events were significantly associated with respiratory diseases among preschool children at lag day 0, lag day 1, and lag day 2, with odds ratios of 1.244 (95% CI, 1.128–1.373), 1.314 (95% CI, 1.189–1.452), and 1.273 (95% CI, 1.152–1.408), respectively. These associations were also significant when the results were adjusted for meteorological variables and other air pollutants.

Conclusions

The study findings suggested that AD exposure increases emergency department visits by children.

Desert dust induces TLR signaling to trigger Th2-dominant lung allergic inflammation via a MyD88-dependent signaling pathway

Asian sand dust (ASD) is known to exacerbate asthma, although its mechanism is not yet well understood. In this study, when the effects on inflammatory response by LPS present in ASD was investigated by measuring the gene expression of cytokines and chemokines in RAW264.7 cells treated with ASD and/or polymyxin B (PMB), the ASD effects were attenuated by PMB, but not completely. When an in vitro study was performed using bone marrow-derived macrophages (BMDMs) from WT, TLR2(-/-), TLR4(-/-), and MyD88(-/-) BALB/c mice and BMDMs from WT, TLR2(-/-), TLR4(-/-), TLR2/4(-/-), TLR7/9(-/-), and MyD88(-/-) C57BL/6J mice, cytokine (IL-6, IL-12) production in BMDMs was higher in ASD-stimulated TLR2(-/-) cells than in TLR4(-/-) cells, whereas it was lower or undetectable in TLR2/4(-/-) and MyD88(-/-) cells. These results suggest that ASD causes cytokine production predominantly in a TLR4/MyD88-dependent pathway. When WT and TLRs 2(-/-), 4(-/-), and MyD88(-/-) BALB/c mice were intratracheally challenged with OVA and/or ASD, ASD caused exacerbation of lung eosinophilia along with Th2 cytokine and eosinophil-relevant chemokine production. Serum OVA-specific IgE and IgG1 similar to WT was observed in TLRs 2(-/-), 4(-/-) mice, but not in MyD88(-/-) mice. The Th2 responses in TLR2(-/-) mice were attenuated remarkably by PMB. These results indicate that ASD exacerbates lung eosinophilia in a MyD88-dependent pathway. TLRs 2 and 4 signaling may be important in the increase in lung eosinophilia. Also, the TLR4 ligand LPS and TLR2 ligand like β-glucan may be strong candidates for exacerbation of lung eosinophilia.

Silica-carrying particulate matter enhances Bjerkandera adusta-induced murine lung eosinophilia

Bjerkandera adusta (B. adusta) causes fungus-associated chronic cough. However, the inflammatory response is not yet fully understood. Recently, B. adusta was identified in Asian sand dust (ASD) aerosol. This study investigated the enhancing effects of ASD on B. adusta-induced lung inflammation. B. adusta was inactivated by formalin. ASD was heated to remove toxic organic substances. ICR mice were intratracheally instilled with saline, B. adusta 0.2 µg, or B. adusta 0.8 µg with or without heated ASD 0.1 mg (H-ASD), four times at 2-week intervals. Two in vitro experiments were conducted to investigate any enhancing effects using bone marrow-derived macrophages (BMDM) from Toll-like receptor (TLR) knockout mice and ICR mice. Co-exposure to H-ASD and B. adusta, especially at high doses, caused eosinophil infiltration, proliferation of goblet cells in the airway, and fibrous thickening of the subepithelial layer, and remarkable increases in expression of Th2 cytokines and eosinophil-related cytokine and chemokine expression in bronchoalveolar lavage fluid. In the in vitro study using BMDM from wild-type, TLR2-/-, and TLR4-/- mice, the TLR-signaling pathway for cytokine production caused by B. adusta was predominantly TLR2 rather than TLR4. H-ASD increased the expression of NF-κB and cytokine production by B. adusta in BMDM from ICR mice. The results suggest that co-exposure to H-ASD and B. adusta caused aggravated lung eosinophilia via remarkable increases of pro-inflammatory mediators. The aggravation of inflammation may be related, at least in part, to the activation of the TLR2-NF-κB signaling pathway in antigen presenting cells by H-ASD.

The Role of Toll-Like Receptors and Myeloid Differentiation Factor 88 in Bjerkandera adusta-Induced Lung Inflammation

BACKGROUND

Recently, a cluster of patients with an intractable allergic fungal cough who were characterized by sensitization to Bjerkandera adusta was reported. In the present study, the role of Toll-like receptors and myeloid differentiation factor 88 (MyD88) in B. adusta-induced lung inflammation was investigated.

METHODS

Wild-type (WT), TLR2-/-,TLR4-/-, and MyD88-/- BALB/c mice were intratracheally challenged with B. adusta 4 times at 2-week intervals. Lung pathology, bronchoalveolar lavage fluid (BALF) cytological profiles, and inflammatory mediators in BALF were investigated. Bone marrow-derived macrophages (BMDM) from TLR2-/-,TLR4-/-, TLR2/4-/-, TLR7/9-/-,MyD88-/-, and WT C57BL/6J mice were stimulated with B. adusta for 12 h, and inflammatory mediators in the culture medium were measured.

RESULTS

B. adusta caused lung inflammation along with Th2 cytokine [interleukin (IL)-5 and IL-13] and eosinophil-related chemokine [eotaxin and monocyte chemotactic protein (MCP-3)] production, an increase in eosinophils in BALF, and eosinophil infiltration in the airways in WT and TLR4-/- mice. However, Th2 and eosinophil-related responses in TLR2-/- and MyD88-/- mice were low or undetectable. The induction of neutrophils and IL-6, IL-12, IL-17A, and MCP-1 in the BALF of MyD88-/- mice was attenuated compared to that in WT mice. The induction of IL-6, TNF-α, MCP-1, and macrophage inflammatory protein-1α was reduced or undetectable in B. adusta-stimulated BMDM from TLR7/9-/- and MyD88-/- mice compared to WT mice.

CONCLUSIONS

These results suggest that TLR2 and the adapter protein MyD88 may play an important role in the induction of eosinophils by B. adusta. However, TLR7/9-MyD88 might be important in the induction of neutrophils and the relevant inflammatory mediators, especially IL-17A.

The Effect of Therapeutic Blockades of Dust Particles-Induced Ca²⁺ Signaling and Proinflammatory Cytokine IL-8 in Human Bronchial Epithelial Cells

Bronchial epithelial cells are the first barrier of defense against respiratory pathogens. Dust particles as extracellular stimuli are associated with inflammatory reactions after inhalation. It has been reported that dust particles induce intracellular Ca(2+) signal, which subsequently increases cytokines production such as interleukin- (IL-) 8. However, the study of therapeutic blockades of Ca(2+) signaling induced by dust particles in human bronchial epithelial cells is poorly understood. We investigated how to modulate dust particles-induced Ca(2+) signaling and proinflammatory cytokine IL-8 expression. Bronchial epithelial BEAS-2B cells were exposed to PM10 dust particles and subsequent mediated intracellular Ca(2+) signaling and reactive oxygen species signal. Our results show that exposure to several inhibitors of Ca(2+) pathway attenuated the PM10-induced Ca(2+) response and subsequent IL-8 mRNA expression. PM10-mediated Ca(2+) signal and IL-8 expression were attenuated by several pharmacological blockades such as antioxidants, IP3-PLC blockers, and TRPM2 inhibitors. Our results show that blockades of PLC or TRPM2 reduced both of PM10-mediated Ca(2+) signal and IL-8 expression, suggesting that treatment with these blockades should be considered for potential therapeutic trials in pulmonary epithelium for inflammation caused by environmental events such as seasonal dust storm.

Meteorological conditions, climate change, new emerging factors, and asthma and related allergic disorders. A statement of the World Allergy Organization

The prevalence of allergic airway diseases such as asthma and rhinitis has increased dramatically to epidemic proportions worldwide. Besides air pollution from industry derived emissions and motor vehicles, the rising trend can only be explained by gross changes in the environments where we live. The world economy has been transformed over the last 25 years with developing countries being at the core of these changes. Around the planet, in both developed and developing countries, environments are undergoing profound changes. Many of these changes are considered to have negative effects on respiratory health and to enhance the frequency and severity of respiratory diseases such as asthma in the general population.

Increased concentrations of greenhouse gases, and especially carbon dioxide (CO₂), in the atmosphere have already warmed the planet substantially, causing more severe and prolonged heat waves, variability in temperature, increased air pollution, forest fires, droughts, and floods – all of which can put the respiratory health of the public at risk. These changes in climate and air quality have a measurable impact not only on the morbidity but also the mortality of patients with asthma and other respiratory diseases. The massive increase in emissions of air pollutants due to economic and industrial growth in the last century has made air quality an environmental problem of the first order in a large number of regions of the world. A body of evidence suggests that major changes to our world are occurring and involve the atmosphere and its associated climate. These changes, including global warming induced by human activity, have an impact on the biosphere, biodiversity, and the human environment. Mitigating this huge health impact and reversing the effects of these changes are major challenges.

This statement of the World Allergy Organization (WAO) raises the importance of this health hazard and highlights the facts on climate-related health impacts, including: deaths and acute morbidity due to heat waves and extreme meteorological events; increased frequency of acute cardio-respiratory events due to higher concentrations of ground level ozone; changes in the frequency of respiratory diseases due to trans-boundary particle pollution; altered spatial and temporal distribution of allergens (pollens, molds, and mites); and some infectious disease vectors. According to this report, these impacts will not only affect those with current asthma but also increase the incidence and prevalence of allergic respiratory conditions and of asthma. The effects of climate change on respiratory allergy are still not well defined, and more studies addressing this topic are needed. Global warming is expected to affect the start, duration, and intensity of the pollen season on the one hand, and the rate of asthma exacerbations due to air pollution, respiratory infections, and/or cold air inhalation, and other conditions on the other hand.

[Evaluation of Cellular Effects Caused by Lunar Regolith Simulant Including Fine Particles]

The National Aeronautics and Space Administration has announced a plan to establish a manned colony on the surface of the moon, and our country, Japan, has declared its participation. The surface of the moon is covered with soil called lunar regolith, which includes fine particles. It is possible that humans will inhale lunar regolith if it is brought into the spaceship. Therefore, an evaluation of the pulmonary effects caused by lunar regolith is important for exploration of the moon. In the present study, we examine the cellular effects of lunar regolith simulant, whose components are similar to those of lunar regolith. We focused on the chemical component and particle size in particular. The regolith simulant was fractionated to < 10 μm, < 25 μm and 10-25 μm by gravitational sedimentation in suspensions. We also examined the cellular effects of fine regolith simulant whose primary particle size is 5.10 μm. These regolith simulants were applied to human lung carcinoma A549 cells at concentrations of 0.1 and 1.0 mg/ml. Cytotoxicity, oxidative stress and immune response were examined after 24 h exposure. Cell membrane damage, mitochondrial dysfunction and induction of Interleukin-8 (IL-8) were observed at the concentration of 1.0 mg/ml. The cellular effects of the regolith simulant at the concentration of 0.1 mg/ml were small, as compared with crystalline silica as a positive control. Secretion of IL-1β and tumor necrosis factor-α (TNF-α) was observed at the concentration of 1.0 mg/ml, but induction of gene expression was not observed at 24 h after exposure. Induction of cellular oxidative stress was small. Although the cellular effects tended to be stronger in the < 10 μm particles, there was no remarkable difference. These results suggest that the chemical components and particle size have little relationship to the cellular effects of lunar regolith simulant such as cell membrane damage, induction of oxidative stress and proinflammatory effect.

PM2.5-rich dust collected from the air in Fukuoka, Kyushu, Japan, can exacerbate murine lung eosinophilia

PM2.5 can exacerbate asthma. Organic substances adsorbed on PM2.5-rich dust (PM2.5rd) were inactivated by heating at 360 °C. To characterize the role of organic substances, the effects of PM2.5rd and heated PM2.5-rich dust (H-PM2.5 rd) on allergic lung inflammation were investigated. BALB/c mice were intratracheally administered PM2.5rd or H-PM2.5rd with or without ovalbumin (OVA) four times at 2-week intervals. PM2.5rd, but not H-PM2.5rd, caused neutrophilic alveolitis and bronchitis. In the presence of OVA, PM2.5rd caused severe eosinophil infiltration and goblet cells proliferation in airways, along with a marked induction of the Th2 cytokines interleukin (IL)-4 and IL-13, and the eosinophil-related cytokine IL-5 in bronchoalveolar lavage fluid (BALF). OVA + H-PM2.5rd caused a weaker response. PM2.5rd showed adjuvant effects on OVA-specific immunoglobulin E (IgE) and IgG1 production, but H-PM2.5rd showed minimal effects. These findings suggested that PM2.5rd-bound substances might aggravate lung eosinophilia. To clarify the roles of TLR2, TLR4, and MyD88 on cytokine production in PM2.5rd, murine bone marrow-derived macrophages (BMDMs) from wild-type (WT), TLR2(-/-), TLR4(-/-), and MyD88(-/-) BALB/c mice were stimulated with dust. Cytokine production was low or undetectable in TLR4(-/-) cells, but occurred from TLR2(-/-) cells, and production by MyD88(-/-) cells was higher than by TLR4(-/-) cells. These results suggest that TLR4 and TLR2 ligands (LPS and β-glucan, respectively) mainly contributed to cytokines production induced by PM2.5rd. In addition to chemical substances, PM2.5-bound microbial substances might act in inflammatory and allergic lung diseases.

Asian sand dust increases MUC8 and MUC5B expressions via TLR4-dependent ERK2 and p38 MAPK in human airway epithelial cells

BACKGROUND

Asian sand dust (ASD) is a natural phenomenon and originates from the deserts of China and is known to contain various chemical and biomolecular components that enhance airway inflammation. The overproduction of airway mucins is an important pathologic finding in inflammatory airway diseases. However, the mechanism of ASD on mucin production of airway epithelial cells has not been elucidated.

OBJECTIVE

To investigate the effect and signaling pathway of ASD on mucin expressions in human airway epithelial cells.

METHODS

In the NCI-H292 cells and the primary cultures of human nasal epithelial cells, the effect and signaling pathway of ASD on MUC8 and MUC5B expressions were investigated using reverse transcriptase-polymerase chain reaction (RT-PCR), real-time PCR, enzyme immunoassay, and immunoblot analysis with several specific inhibitors and small interfering RNA (siRNA).

RESULTS

ASD increased MUC8 and MUC5B expressions and activated the phosphorylations of extracellular signal-regulated kinase 1/2 (ERK1/2) and p38 mitogen-activated protein kinase (MAPK). U0126 (ERK1/2 MAPK inhibitor) and SB203580 (p38 MAPK inhibitor) inhibited ASD-induced MUC8 and MUC5B expressions. In addition, knockdowns of ERK2 and p38 MAPK by siRNA blocked ASD-induced MUC8 and MUC5B mRNA expressions. Toll-like receptor 4 (TLR4) mRNA expression was increased after treatment with ASD. Knockdown of TLR4 by siRNA blocked ASD-induced MUC8 and MUC5B mRNA expressions. Furthermore, the phosphorylations of ERK1/2 and p38 MAPK were blocked by knockdown of TLR4.

CONCLUSIONS

These results show that ASD induces MUC8 and MUC5B expressions via TLR4-dependent ERK2 and p38 MAPK signaling pathway in human airway epithelial cells.

Asian sand dust causes subacute peripheral immune modification with NF-κB activation

Asian sand dust (ASD), a type of particulate matter found in Asia, migrates to East Asia. The increased airborne spread of ASD has led to concerns regarding possible adverse health effects. Our group previously reported that ASD induces lung inflammation in mice, but it is still unclear whether ASD affects lymphoid organs. In this study, we investigated the effect of ASD on splenocytes in a mouse model of ASD exposure. ICR mice were intratracheally administered a single dose of normal saline (control) or ASD and were subsequently sacrificed 1 or 3 days later. TNF-α production in bronchoalveolar lavage fluids was higher at day 1, but not at day 3, after ASD administration. The enzyme-linked immunosorbent assay results showed that ASD administration increased mitogen-induced IL-2, TNF-α, and IL-6 production in splenocytes. Additionally, cell viability assay showed enhanced splenocyte proliferation at day 3, but not at day 1, after ASD administration. The electrophoretic mobility shift assay results demonstrated that nuclear factor κB (NF-κB) was activated in splenocytes on day 3, but not on day 1. In particular, NF-κB activation was detected in CD4(+) and CD11b(+) cells on day 3. These results suggest that ASD induces subacute inflammatory responses with NF-κB activation in the spleen, in contrast to acute inflammation in the lungs.

Decreased pulmonary function in school children in Western Japan after exposures to Asian desert dusts and its association with interleukin-8

The objective of the study was to investigate the influence of Asian dust storms (ADS) on pulmonary function of school children and the relationship of this effect with interleukin-8. Morning peak expiratory flow (PEF) was measured daily in 399 children from April to May 2012 and in 384 of these children from March to May 2013. The data were analyzed for an association between ADS events and PEF by linear mixed models. Interleukin-8 transcriptional activity was assessed in THP-G8 cells stimulated by airborne particles collected on ADS days. Seven ADS days were identified: April 23 and 24, 2012; March 8 to 10, 2013; and March 19 and 20, 2013. Changes in PEF after ADS exposure were -8.17 L/min (95% confidence interval, -11.40 to -4.93) in 2012 and -1.17 L/min (-4.07 to 1.74) in 2013, and there was a significant difference between 2012 and 2013. Interleukin-8 transcriptional activity was significantly higher in 2012 at 10.6 ± 2.9-fold compared to 3.7 ± 0.4 in March 8 to 10, 2013, and 2.3 ± 0.2 in March 19 and 20, 2013. The influence of ADS events on pulmonary function of children differs with each ADS event and may be related to interleukin-8 production.

Molecular characterization of microbial communities in bioaerosols of a coal mine by 454 pyrosequencing and real-time PCR

Microbial diversity and abundance in bioaerosols of a coal mine were analyzed based on 454 pyrosequencing and real-time polymerase chain reaction (PCR). A total of 37,191 high quality sequences were obtained and could be classified into 531, 1730 and 448 operational taxonomic units respectively for archaea, bacteria and fungi at 97% sequence similarity. The Shannon diversity index for archaea, bacteria and fungi was respectively 4.71, 6.29 and 3.86, indicating a high diversity in coal mine bioaerosols. Crenarchaeota, Proteobacteria and Ascomycota were the dominant phyla for archaea, bacteria and fungi, respectively. The concentrations of total archaea, bacteria and fungi were 1.44×10(8), 1.02×10(8) and 9.60×10(4) cells/m3, respectively. Methanotrophs observed in bioaerosols suggested possible methane oxidation in the coal mine. The identified potential pathogens to coal miners, such as Acinetobacter schindleri, Aeromonas cavernicola, Alternaria alternata, Aspergillus penicillioides, Cladosporium cladosporioides, and Penicillium brevicompactum were also observed. This was the first investigation of microbial diversity and abundance in coal mine bioaerosols. The investigation of microbial communities would be favorable in promoting the progress of methane control based on microbial technique and concern on coal miners' health.

The relationship between Asian dust events and out-of-hospital cardiac arrests in Japan

BACKGROUND

Asian dust events are caused by dust storms that originate in the deserts of China and Mongolia and drift across East Asia. We hypothesized that the dust events would increase incidence of out-of-hospital cardiac arrests by triggering acute events or exacerbating chronic diseases.

METHODS

We analyzed the Utstein-Style data collected in 2005 to 2008 from seven prefectures covering almost the entire length of Japan to investigate the effect of Asian dust events on out-of-hospital cardiac arrests. Asian dust events were defined by the measurement of light detection and ranging. A time-stratified case-crossover analysis was performed. The strength of the association between Asian dust events and out-of-hospital cardiac arrests was shown by odds ratios and 95% confidence intervals in two conditional logistic models. A pooled estimate was obtained from area-specific results by random-effect meta-analysis.

RESULTS

The total number of cases of out-of-hospital cardiac arrest was 59 273, of which 35 460 were in men and 23 813 were in women. The total number of event days during the study period was smallest in Miyagi and Niigata and largest in Shimane and Nagasaki. There was no significant relationship between Asian dust events and out-of-hospital cardiac arrests by area in either of the models. In the pooled analysis, the highest odds ratios were observed at lag day 1 in both model 1 (OR 1.07; 95% CI, 0.97-1.19) and model 2 (OR 1.08; 95% CI, 0.97-1.20). However, these results were not statistically significant.

CONCLUSIONS

We found no evidence of an association between Asian dust events and out-of-hospital cardiac arrests.

Asian sand dust aggregate causes atopic dermatitis-like symptoms in Nc/Nga mice

Background

Asian sand dust (ASD) originates from the arid and semiarid areas of China, and epidemiologic studies have shown that ASD exposure is associated with various allergic and respiratory symptoms. However, few studies have been performed to assess the relationship between skin inflammation and ASD exposure.

Methods

Twelve-week-old NC/Nga mice were divided into 6 groups (n = 8 for each group): hydrophilic petrolatum only (control); hydrophilic petrolatum plus ASD (ASD); hydrophilic petrolatum and heat inactivated-ASD (H-ASD); Dermatophagoides farinae extract (Df); Df and ASD (Df + ASD), and; Df and H-ASD (Df + H-ASD). The NC/Nga mice in each group were subjected to treatment twice a week for 4 weeks. We evaluated skin lesions by symptoms, pathologic changes, and serum IgE levels.

Results

ASD alone did not induce atopic dermatitis (AD)-like skin symptoms. However, Df alone, Df + H-ASD and Df + ASD all induced AD-like symptoms, and dermatitis scores in the group of Df + ASD group were significantly greater than that of the Df group (P = 0.0011 at day 21; and P = 0.017 at day 28). Mean serum IgE was markedly increased in the Df and Df + ASD groups, compared to the ASD and control groups (P < 0.0001), and serum IgE levels in the Df + ASD group were significantly higher compared to the Df group (P = 0.003).

Conclusions

ASD alone did not cause AD-like symptoms in NC/Nga mice. However, AD-like symptoms induced by Df, a major allergen, were enhanced by adding ASD. Although no epidemiological studies have been conducted for the association between ASD and symptoms of dermatitis, our data suggest that it is likely that ASD may contribute to the exacerbation of not only respiratory symptoms, but also skin diseases, in susceptible individuals.

Influence of Asian dust particles on immune adjuvant effects and airway inflammation in asthma model mice

OBJECTIVE

An Asian dust storm (ADS) contains airborne particles that affect conditions such as asthma, but the mechanism of exacerbation is unclear. The objective of this study was to compare immune adjuvant effects and airway inflammation induced by airborne particles collected on ADS days and the original ADS soil (CJ-1 soil) in asthma model mice.

METHODS

Airborne particles were collected on ADS days in western Japan. NC/Nga mice were co-sensitized by intranasal instillation with ADS airborne particles and/or Dermatophagoides farinae (Df), and with CJ-1 soil and/or Df for 5 consecutive days. Df-sensitized mice were stimulated with Df challenge intranasally at 7 days after the last Df sensitization. At 24 hours after challenge, serum allergen specific antibody, differential leukocyte count and inflammatory cytokines in bronchoalveolar lavage fluid (BALF) were measured, and airway inflammation was examined histopathologically.

RESULTS

Co-sensitization with ADS airborne particles and Df increased the neutrophil and eosinophil counts in BALF. Augmentation of airway inflammation was also observed in peribronchiolar and perivascular lung areas. Df-specific serum IgE was significantly elevated by ADS airborne particles, but not by CJ-1 soil. Levels of interleukin (IL)-5, IL-13, IL-6, and macrophage inflammatory protein-2 were higher in BALF in mice treated with ADS airborne particles.

CONCLUSION

These results suggest that substances attached to ADS airborne particles that are not in the original ADS soil may play important roles in immune adjuvant effects and airway inflammation.

Silica and double-stranded RNA synergistically induce bronchial epithelial apoptosis and airway inflammation

Silica crystals (silica), which are the main mineral component of volcanic ash and desert dust, can activate the caspase-1-activating inflammasome in phagocytic cells to secrete IL-1β. Although inhalation of silica-containing dust is known to exacerbate chronic respiratory diseases, probably through inflammasome activation, its direct effects on bronchial epithelial cells remain unclear. Here, we show that silica and double-stranded RNA (dsRNA) synergistically induces caspase-9-dependent apoptosis, but not inflammasome activation, of bronchial epithelial cells. Intranasal administration of silica and dsRNA to mice synergistically enhanced neutrophil infiltration in the airway without IL-1β release in the bronchoalveolar lavage fluid. Histopathological analysis revealed that silica or dsRNA alone induced slight airway inflammation, whereas combined administration significantly enhanced airway inflammation and epithelial damage. These novel findings suggest that inhalation of silica-containing dust may cause inflammasome-independent airway inflammation, possibly by damaging the epithelial barrier, especially at the time of viral infection. These responses may also be involved in acute lung injury caused by inhaled silica-containing dust.

Aggravation of ovalbumin-induced murine asthma by co-exposure to desert-dust and organic chemicals: an animal model study

BACKGROUND

The organic chemicals present in Asian sand dust (ASD) might contribute to the aggravation of lung eosinophila. Therefore, the aggravating effects of the Tar fraction from ASD on ovalbumin (OVA)-induced lung eosinophilia were investigated.

METHODS

The Tar fraction was extracted from ASD collected from the atmosphere in Fukuoka, Japan. ASD collected from the Gobi desert was heated at 360°C to inactivate toxic organic substances (H-ASD). ICR mice were instilled intratracheally with 12 different test samples prepared with Tar (1 μg and 5 μg), H-ASD, and OVA in a normal saline solution containing 0.02% Tween 80. The lung pathology, cytological profiles in the bronchoalveolar lavage fluid (BALF), inflammatory cytokines/chemokines in BALF and OVA-specific immunoglobulin in serum were investigated.

RESULTS

Several kinds of polycyclic aromatic hydrocarbons (PAHs) were detected in the Tar sample. H-ASD + Tar 5 μg induced slight neutrophilic lung inflammation. In the presence of OVA, Tar 5 μg increased the level of eosinophils slightly and induced trace levels of Th2 cytokines IL-5 and IL-13 in BALF. Also mild to moderate goblet cell proliferation and mild infiltration of eosinophils in the submucosa of airway were observed. These pathological changes caused by H-ASD + OVA were relatively small. However, in the presence of OVA and H-ASD, Tar, at as low a level as 1 μg, induced severe eosinophil infiltration and proliferation of goblet cells in the airways and significantly increased Th2 cytokines IL-5 and IL-13 in BALF. The mixture showed an adjuvant effect on OVA-specific IgG1 production.

CONCLUSIONS

These results indicate that H-ASD with even low levels of Tar exacerbates OVA-induced lung eosinophilia via increases of Th2-mediated cytokines. These results suggest that ASD-bound PAHs might contribute to the aggravation of lung eosinophila.