Asian sand dust aggravates allergic rhinitis in guinea pigs induced by Japanese cedar pollen

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.

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.

A Pathological Study of Acute Pulmonary Toxicity Induced by Inhaled Kanto Loam Powder

The frequency and volume of Asian sand dust (ASD) (Kosa) are increasing in Japan, and it has been reported that ASD may cause adverse respiratory effects. The pulmonary toxicity of ASD has been previously analyzed in mice exposed to ASD particles by intratracheal instillation. To study the pulmonary toxicity induced by inhalation of ASD, ICR mice were exposed by inhalation to 50 or 200 mg/m³ Kanto loam powder, which resembles ASD in elemental composition and particle size, for 6 h a day over 1, 3, 6, 9, or 15 consecutive days. Histological examination revealed that Kanto loam powder induced acute inflammation in the whole lung at all the time points examined. The lesions were characterized by infiltration of neutrophils and macrophages. The intensity of the inflammatory changes in the lung and number of neutrophils in both histological lesions and bronchoalveolar lavage fluid (BALF) appeared to increase over time. Immunohistochemical staining showed interleukin (IL)-6- and tumor necrosis factor (TNF)-α-positive macrophages and a decrease in laminin positivity in the inflammatory lesions of the lung tissues. Electron microscopy revealed vacuolar degeneration in the alveolar epithelial cells close to the Kanto loam particles. The nitric oxide level in the BALF increased over time. These results suggest that inhaled Kanto loam powder may induce diffuse and acute pulmonary inflammation, which is associated with increased expression of inflammatory cytokines and oxidative stress.

Transcriptome analysis of airborne PM2.5-induced detrimental effects on human keratinocytes

Ambient air pollution is becoming more severe worldwide, posing a serious threat to human health. Fine airborne particles of particulate matter (PM_2.5) show higher cytotoxicity than other coarse fractions. Indeed, PM_2.5 induces cardiovascular or respiratory damage; however, few studies have evaluated the detrimental effect of PM_2.5 to normal human skin. We used a next-generation sequencing-based (RNA-Seq) method with transcriptome and Gene Ontology (GO) enrichment analysis to determine the harmful influences of PM_2.5 on human normal epidermal keratinocytes. DAVID analysis showed that the most significantly enriched GO terms were associated with epidermis-related biological processes such as "epidermis development (GO: 0008544)" and "keratinocyte differentiation (GO: 0030216)", suggesting that PM_2.5 has some deleterious effects to the human epidermis. In addition, Ingenuity Pathway Analysis predicted inflammation-related signaling as one of the major PM_2.5-induced signaling pathways, and pro-inflammatory cytokines as upstream regulators with symptoms similar to psoriasis as downstream effects. PM_2.5 caused considerable changes in the expression of pro-inflammatory cytokines and psoriatic skin disease-related genes, might lead to epidermal dysfunctions. Our results might help to understand the mechanism of air pollution-induced skin barrier perturbation and contribute to the development of a new strategy for the prevention or recovery of the consequent damage.

The Association between Ambient Air Pollution and Allergic Rhinitis: Further Epidemiological Evidence from Changchun, Northeastern China

With the continuous rapid urbanization process over the last three decades, outdoors air pollution has become a progressively more serious public health hazard in China. To investigate the possible associations, lag effects and seasonal differences of urban air quality on respiratory health (allergic rhinitis) in Changchun, a city in Northeastern China, we carried out a time-series analysis of the incidents of allergic rhinitis (AR) from 2013 to 2015. Environmental monitoring showed that PM_2.5 and PM₁₀ were the major air pollutants in Changchun, followed by SO₂, NO₂ and O₃. The results also demonstrated that the daily concentrations of air pollutants had obvious seasonal differences. PM₁₀ had higher daily mean concentrations in spring (May, dust storms), autumn (October, straw burning) and winter (November to April, coal burning). The mean daily number of outpatient AR visits in the warm season was higher than in the cold season. The prevalence of allergic rhinitis was significantly associated with PM_2.5, PM₁₀, SO₂ and NO₂, and the increased mobility was 10.2% (95% CI, 5.5%–15.1%), 4.9% (95% CI, 0.8%–9.2%), 8.5% (95% CI, −1.8%–19.8%) and 11.1% (95% CI, 5.8%–16.5%) for exposure to each 1-Standard Deviation (1-SD) increase of pollutant, respectively. Weakly or no significant associations were observed for CO and O₃. As for lag effects, the highest Relative Risks (RRs) of AR from SO₂, NO₂, PM₁₀ and PM_2.5 were on the same day, and the highest RR from CO was on day 4 (L4). The results also indicated that the concentration of air pollutants might contribute to the development of AR. To summarize, this study provides further evidence of the significant association between ambient particulate pollutants (PM_2.5 and PM₁₀, which are usually present in high concentrations) and the prevalence of respiratory effects (allergic rhinitis) in the city of Changchun, located in Northeastern China. Environmental control and public health strategies should be enforced to address this increasingly challenging problem.

Effects of Asian Dust Particles on the Early-Stage Antigen-Induced Immune Response of Asthma in NC/Nga Mice

Asian dust (AD) can aggravate airway inflammation in asthma, but the association between AD and the development of asthma remains unclear. This study aimed to investigate the effects of AD on the early stage of antigen sensitization using a mouse model of asthma, as well as the role of leukotrienes (LTs) in antigen-induced airway inflammation potentiated by AD particles. NC/Nga mice were co-sensitized by intranasal instillation of AD particles and/or Dermatophagoides farinae (Df) for five consecutive days. Df-sensitized mice were stimulated with an intranasal Df challenge at seven days. Mice were treated with the type 1 cysteinyl LT (CysLT₁) receptor antagonist orally 4 h before and 1 h after the allergen challenge. At 24 h post-challenge, the differential leukocyte count, inflammatory cytokines, and LTs in bronchoalveolar lavage fluid were assessed, and airway inflammation was evaluated histopathologically. AD augmented neutrophilic and eosinophilic airway inflammation with increased CysLTs and dihydroxy-LT in a mouse model of asthma. The CysLT₁ receptor antagonist was shown to attenuate both neutrophilic and eosinophilic airway inflammation augmented by AD. Therefore, exposure to AD may be associated with the development of asthma and LTs may play important roles in airway inflammation augmented by AD.

Human bronchial epithelial cell injuries induced by fine particulate matter from sandstorm and non-sandstorm periods: Association with particle constituents

Epidemiological studies have demonstrated the exacerbation of respiratory diseases following sandstorm-derived particulate matter (PM) exposure. The presence of anthropogenic and biological agents on the sandstorm PM and the escalation of PM<2.5μm (PM2.5) pollution in China have led to serious concerns regarding the health effects of PM2.5 during Asian sandstorms. We investigated how changes in PM2.5 composition, as the weather transitioned towards a sandstorm, affected human airway epithelial cells. Six PM2.5 samples covering two sandstorm events and their respective background and transition periods were collected in Baotou, an industrial city near the Gobi Desert in China. PM samples from all three periods had mild cytotoxicity in human bronchial epithelial cell line BEAS-2B, which was positively correlated with the contents of polycyclic aromatic hydrocarbons and several metals. All PM samples potently increased the release of interleukin-6 (IL-6) and interleukin-8 (IL-8). Endotoxin in all samples contributed significantly to the IL-6 response, with only a minor effect on IL-8. Cr was positively correlated with both IL-6 and IL-8 release, while Si was only associated with the increase of IL-6. Our study suggests that local agricultural and industrial surroundings in addition to the sandstorm play important roles in the respiratory effects of sandstorm-derived PM.

Effect of desert dust exposure on allergic symptoms: A natural experiment in Japan

BACKGROUND

Desert dust originating from arid and semiarid areas is transported to widespread regions, including Japan. Desert dust particles exert adjuvant effects in animals.

OBJECTIVE

To examine whether desert dust enhances allergic symptoms in real-life settings and to explore its effect modifiers.

METHODS

We conducted an observational study of 3,327 pregnant women during spring and fall in October 2011 to May 2013 in 3 regions in Japan as an adjunct study of the Japan Environment & Children's Study. We acquired participants' daily symptom scores by sending a questionnaire to their mobile phones on high desert-dust days (>0.07/km) and on some randomly selected other days (control days) for each participant.

RESULTS

Pregnant women had an increased risk of allergic symptoms on high desert-dust days (adjusted odds ratio [OR], 1.10; 95% CI, 1.04-1.18). The increased OR was mostly driven by those who showed positive IgE to Japanese cedar pollen when pollen simultaneously dispersed (adjusted OR, 1.25; 95% CI, 1.13-1.38), whereas no clear risk increase was observed in the absence of pollen or for participants with negative IgE to Japanese cedar pollen. The risk elevation was observed from low levels of desert dust in a dose-dependent manner even on control days.

CONCLUSION

Ambient desert dust level was associated with an increased risk of allergic symptoms in pollen-sensitized pregnant women when pollen was present in the air. The risk increase was dose dependent and was observed from low levels of desert dust. These results support a hypothesis that ambient desert dust particles exert adjuvant effects in human in real-life settings.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: UMIN000010826.

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.

The effect of PM10 on allergy symptoms in allergic rhinitis patients during spring season

Background: Asian sand dust (ASD) that originates in the Mongolian Desert in the spring induces serious respiratory health problems throughout East Asia (China, Korea, Japan). PM₁₀ (particulate matter with an aerodynamic diameter <10 μm) is a major air pollutant component in ASD. We studied the effects of PM₁₀ on allergy symptoms in patients with allergic rhinitis during the spring season, when ASD frequently develops. Methods: We investigated the changes in allergic symptoms in 108 allergic patients and 47 healthy subjects by comparing their 120-day symptom scores from February to May 2012. At the same time, the contributions of pollen count and PM₁₀ concentration were also assessed. We also compared symptom scores before and 2 days after the daily PM₁₀ concentration was >100 μg/m³. Results: The PM₁₀ concentration during the 120 days was <150 μg/m³. No significant correlations were observed between changes in the PM₁₀ concentration and allergic symptom scores (p > 0.05). However, allergic symptoms were significantly correlated with outdoor activity time (p < 0.001). Conclusions: These results demonstrate that a PM₁₀ concentration <150 μg/m³ did not influence allergy symptoms in patients with allergic rhinitis during the 2012 ASD season.

Effect of Asian sand dust on Japanese cedar pollinosis

OBJECTIVE

Asian sand dust (ASD), originating in the deserts of Mongolia and China, spreads over large areas and is associated with adverse effects on human health in East Asia, including asthma, heart disease, and some allergic diseases. However, the effect of ASD on patients with seasonal allergic rhinitis caused by Japanese cedar pollen (SAR-JCP), the most common form of allergic rhinitis, remains unclear. The aim of this study was to investigate the effect of ASD on SAR-JCP patients.

METHODS

A total of 41 patients with SAR-JCP recorded nasal and ocular allergic symptom scores in a diary. We assessed the influence of ASD events on patients with SAR-JCP during the JCP season and before and after the JCP season.

RESULTS

ASD events did not influence nasal and ocular allergy symptoms during the JCP season. Scores for sneezing and runny nose were significantly increased by ASD events in the pre-JCP season. Ocular symptom scores were significantly increased by ASD events in the post-JCP season.

CONCLUSION

Our results suggest that ASD may exacerbate allergy symptoms even before mass scattering of JCP, which usually does not cause allergic symptoms in patients with SAR-JCP. ASD also induced conjunctivitis symptoms after the JCP season. However, we did not observe any adverse effects of ASD on allergic symptoms during the JCP season.

Asian dust particles induce macrophage inflammatory responses via mitogen-activated protein kinase activation and reactive oxygen species production

Asian dust is a springtime meteorological phenomenon that originates in the deserts of China and Mongolia. The dust is carried by prevailing winds across East Asia where it causes serious health problems. Most of the information available on the impact of Asian dust on human health is based on epidemiological investigations, so from a biological standpoint little is known of its effects. To clarify the effects of Asian dust on human health, it is essential to assess inflammatory responses to the dust and to evaluate the involvement of these responses in the pathogenesis or aggravation of disease. Here, we investigated the induction of inflammatory responses by Asian dust particles in macrophages. Treatment with Asian dust particles induced greater production of inflammatory cytokines interleukin-6 and tumor necrosis factor-α (TNF-α) compared with treatment with soil dust. Furthermore, a soil dust sample containing only particles ≤10 μm in diameter provoked a greater inflammatory response than soil dust samples containing particles >10 μm. In addition, Asian dust particles-induced TNF-α production was dependent on endocytosis, the production of reactive oxygen species, and the activation of nuclear factor-κB and mitogen-activated protein kinases. Together, these results suggest that Asian dust particles induce inflammatory disease through the activation of macrophages.

Inflammatory and degranulation effect of yellow sand on RBL-2H3 cells in relation to chemical and biological constituents

Recent studie pointed out that allergic diseases have increased during the Asian dust storm event (ADSE) in Japan. Daily observations and the atmospheric concentrations of yellow sand (YS) aerosol have been increasing. In this study, YS samples collected from three sites of Japan during ADSE in 2009-2010 were used. The particles were analyzed by X-ray photoelectron spectroscopy (XPS) and X-ray fluorescence-energy dispersive spectrometer (XRF-EDS). We investigate ability of YS extract on enhancing the chemical mediator release and cytokine production from rat basophilic leukemia (RBL-2H3) cells. The dust particles at Fukuoka and Tsukuba were abundant in aluminum (Al), iron (Fe), potassium (K) and titan (Ti) than those at Naha. Concentration of the trace endotoxin and Cryptomeria japonica pollen allergen (Cry j 1) were measured in YS extract. After exposure of RBL-2H3 cells to YS extract, the β-hexosaminidase (β-hex) release, tumor necrosis factor-alpha (TNF-α) production were enhanced in RBL-2H3 cells. This process depends on endotoxin, Cry j 1 and other allergen present in the YS extract. YS water extract also show a strong cytotoxic effect on the cells. This data suggest that low levels of endotoxin and Cry j 1 in YS may cause allergy during the ADSE.

[Possibility of exacerbation of allergy by lunar regolith]

Japan, U.S.A. and other foreign space agencies have plans for the construction of a lunar base and long-term stay of astronauts on the moon. The surface of the moon is covered by a thick layer of soil that includes fine particles called "lunar regolith", which is formed by meteorite impact and space weathering. Risk assessment of particulate matter on the moon is important for astronauts working in microgravity on the moon. However, there are few investigations about the biological influences of lunar regolith. Especially, there is no investigation about allergic activity to lunar regolith. The main chemical components of lunar regolith are SiO2, Al2O3, CaO, FeO, etc. Of particular interest, approximately 50% of lunar regolith consists of SiO2. There is a report that the astronauts felt hay fever-like symptoms from the inhalation of the lunar regolith. Yellow sand, whose chemical components are similar to lunar regolith, enhances allergenic reactions, suggesting the possibility that lunar regolith has an adjuvant-like activity. Although intraperitoneal administration of lunar regolith with ovalbumin to mouse did not show enhancement of allergenic reactions, further evaluation of lunar regolith's potential to exacerbate the effects of allergies is essential for development of the moon.

Early interventional treatment with intranasal mometasone furoate in Japanese cedar/cypress pollinosis: a randomized placebo-controlled trial

BACKGROUND

Little is known about the safety and effectiveness of early interventional treatment (EIT) with intranasal corticosteroids for seasonal allergic rhinitis. We designed a double-blinded, randomized, placebo-controlled 12-week trial of EIT with mometasone furoate nasal spray (MFNS) for Japanese cedar/cypress pollinosis (JCCP).

METHODS

A total of 50 JCCP patients received MFNS (200μg once daily: n = 25) or placebo (n = 25) starting on February 1, 2010. Treatments continued until the end of April. The primary endpoint was the comparison of the total nasal symptom score (TNSS) between the MFNS and placebo groups. The secondary endpoints included comparisons of QOL, daytime sleepiness, nasal ECP levels, and safety.

RESULTS

Continuous dispersion of Japanese cedar pollen began on February 22. Although the placebo group showed a significant worsening of symptoms after the start of the continuous dispersion, no worsening occurred in the MFNS group. A significant difference in the TNSS between the two groups was seen starting at 4 weeks after the treatment. Similar results were seen for QOL and sleepiness. Nasal ECP levels in March were significantly lower in the MFNS group. A total of 56% of the MFNS group progressed to a persistent allergic rhinitis state in accordance with the ARIA classification, as opposed to 84% of the placebo group. MFNS was well tolerated, and the plasma cortisol concentrations were similar between the two groups.

CONCLUSIONS

EIT with MFNS for JCCP is both safe and effective. This treatment can potentially lessen symptoms and help pollinosis patients remain in the intermittent state.

Asian sand dust enhances allergen-induced th2 allergic inflammatory changes and mucin production in BALB/c mouse lungs

Purpose

Recent studies have reported that Asian sand dust (ASD) has a potential risk of aggravating airway inflammation. The purpose of this study was to investigate the effect of ASD on inflammation and mucin production in the airways of allergic mice.

Methods

Forty BALB/c female mice were divided into four groups: saline (group 1); ASD (group 2); ovalbumin (OVA) alone (group 3); and OVA+ASD (group 4). OVA-specific immunoglobulin E (IgE) in serum and interleukin (IL)-4, IL-5, IL-13, and interferon-gamma (IFN-γ) in bronchoalveolar lavage fluid (BALF) were measured by enzyme-linked immunosorbent assay (ELISA). Hematoxylin & eosin (H&E) and Periodic acid-Schiff (PAS) staining was performed on lung tissues. In addition, immunohistochemical staining for IL-4, IL-5, MUC5AC, and transforming growth factor alpha (TGF-α) was conducted.

Results

Serum IgE levels were significantly higher in group 4 than in group 3 (P<0.05). IL-4 and IL-5 in BALF were significantly higher in group 4 than in group 3 (P<0.05, respectively). Based on H&E staining, inflammatory cell numbers were significantly greater in group 4 than in the other groups (P<0.05). The number of PAS-positive cells was also significantly greater in groups 3 and 4 than in groups 1 and 2 (P<0.05). The numbers of IL-4 and IL-5-positive cells were higher in group 4 than in group 3 (P<0.05). The number of MUC5AC and TGF-α-positive cells were also higher in group 4 than in group 3 (P<0.05).

Conclusions

Our data suggest that ASD increases cytokine expression and mucin production in an allergic murine model. The increased inflammatory reactions were related to cytokine production.

Effect of Asian Sand Dust on Mucin Production in NCI-H292 Cells and Allergic Murine Model

Objective. To investigate the effect of Asian sand dust (ASD) on mucin production in human respiratory epithelial cells in vitro and in allergic murine nasal epithelial cells.

Study Design. Controlled, in vitro.

Setting. Academic research laboratory.

Materials and Methods. Human NCI-H292 cells were treated with ASD and analyzed by immunostaining, reverse transcriptase–polymerase chain reaction for MUC5AC mRNA expression, and Periodic Acid Schiff (PAS) staining. Forty female BALB/c mice were classified into 4 groups. Two groups were sensitized with ovalbumin (OVA), and 1 of these was treated with ASD (ASD+OVA). The 2 nonsensitized groups were treated with ASD or saline. Then the murine nasal mucosal tissues were evaluated by hematoxylin and eosin (H&E) staining, PAS staining, and immunostaining for MUC5AC and transforming growth factor (TGF)-α proteins.

Results. The numbers of MUC5AC-immunopositive NCI-H292 cells and PAS-positive NCI-H292 cells were significantly higher in the ASD-treated cells than in the control cells ( P = .039 and P = .029, respectively). MUC5AC mRNA expression in the cells increased with increasing concentrations of ASD. In the murine nasal epithelial tissues, the numbers of eosinophils and PAS-positive cells were significantly higher in the ASD+OVA group than in the OVA group (H&E staining, P = .037; PAS staining, P = .019). At 2 weeks, the numbers of MUC5AC- and TGF-α–positive cells in the nasal epithelial tissue were significantly higher in the ASD+OVA group than in the OVA group ( P = .031 and P = .033, respectively).

Conclusion. ASD can induce mucin production in respiratory epithelial cells.

Impact of air pollution on allergic diseases

The incidence of allergic diseases in most industrialized countries has increased. Although the exact mechanisms behind this rapid increase in prevalence remain uncertain, a variety of air pollutants have been attracting attention as one causative factor. Epidemiological and toxicological research suggests a causative relationship between air pollution and the increased incidence of asthma, allergic rhinitis, and other allergic disorders. These include ozone, nitrogen dioxide and, especially particulate matter, produced by traffic-related and industrial activities. Strong epidemiological evidence supports a relationship between air pollution and the exacerbation of asthma and other respiratory diseases. Recent studies have suggested that air pollutants play a role in the development of asthma and allergies. Researchers have elucidated the mechanisms whereby these pollutants induce adverse effects; they appear to affect the balance between antioxidant pathways and airway inflammation. Gene polymorphisms involved in antioxidant pathways can modify responses to air pollution exposure. While the characterization and monitoring of pollutant components currently dictates pollution control policies, it will be necessary to identify susceptible subpopulations to target therapy/prevention of pollution-induced respiratory diseases.

Asian dust storm particles induce a broad toxicological transcriptional program in human epidermal keratinocytes

Exposure to airborne dust particles originated from seasonal Asian dust storms in Chinese and Mongolian deserts results in increased incidence of a range of diseases including asthma, contact dermatitis and conjunctivitis. The areas affected by Asian dust particles extend from East China to the west coast of North America. In order to study toxicological mechanisms in human skin, we evaluated the effects of dust particles collected during Asian dust storms (Asian dust particles) on gene expression in human epidermal keratinocytes (HEK). In HEK, exposure to Asian dust particles significantly increased gene expressions of cytochrome P450 1A1 (CYP1A1), CYP1A2, and CYP1B1, which is an indication of aryl hydrocarbon receptor (AHR) activation. In addition, Asian dust particles increased gene transcription of the cytokines IL-6, IL-8, and GM-CSF, which have broad pro-inflammatory and immunomodulatory properties. Asian dust particles significantly up-regulated expression of caspase 14 in HEK, suggesting that Asian dust particles directly affect keratinocyte differentiation. We also demonstrated that protein extract of pollen, a material frequently adsorbed onto Asian dust particles, potentially contributes to the increased transcription of IL-6, CYP1A1, CYP1A2, and CYP1B1. Taken together, these studies suggest that Asian dust particles can exert toxicological effects on human skin through the activation of the cellular detoxification system, the production of pro-inflammatory and immunomodulatory cytokines, and changes in the expression of proteins essential in normal epidermal differentiation.

Urban particulate matter in Beijing, China, enhances allergen-induced murine lung eosinophilia

It has been reported that ambient particulate matter (PM) in some large cities, such as Beijing, China, causes adverse respiratory health effects. However, there is currently no experimental report on the relationship between bronchial asthma and urban PM (UPM) in northeast Asia. In this study, the microbial and chemical substances adsorbed onto UPM collected in Beijing were excluded by heat-treatment at 360 degrees C for 30 min. The effects of UPM or heated UPM (H-UPM) toward allergic lung inflammation were compared in murine lungs to investigate the role of organic substances. ICR mice were administrated intratracheally with the two kinds of UPM and/or ovalbumin (OVA) 4 times at 2-week intervals. UPM and H-UPM enhanced eosinophil recruitment induced by OVA in the alveoli and in the submucosa of the airway, which has a goblet cell proliferation in the bronchial epithelium. UPM and H-UPM synergistically increased Th-2 cytokines--interleukin (IL)-4 and IL-13, eosinophil-relevant cytokines and chemokines, such as IL-5 and monocyte chemotactic protein-3 (MCP-3), induced by OVA in bronchoalveolar lavage fluid (BALF). The enhancing effects were much greater in UPM than in H-UPM. UPM induced adjuvant effects on specific immunoglobulin E (IgE) and IgG1 production by OVA. In an in vitro study using RAW264.7 cells, UPM increased the expression of Toll-like receptor 2 (TLR2) mRNA, but not TLR4 mRNA. H-UPM caused no expression of both TLR mRNAs. These results suggest that the aggravated lung eosinophilia in UPM was due to activation of a Th2-associated immune response via the activation of TLR2 by microbial materials. Chemical materials of air pollutant origin contained in UPM, and inorganic components (elemental carbon, mineral elements) in H-UPM, could also cause the aggravation.