The role of particulate pollutants in pulmonary inflammation and asthma: evidence for the involvement of organic chemicals and oxidative stress

Doxorubicin Incorporation into Gold Nanoparticles: An In Vivo Study of Its Effects on Cardiac Tissue in Rats

Gold nanoparticles (Au-NPs) have been explored as potential vectors for enhancing the antitumor efficacy of doxorubicin (DOX) while minimizing its cardiotoxic effects. However, the impacts of DOX Au-NPs on cardiac function and oxidative stress remain inadequately understood. This study aimed to explore the effects of DOX Au-NPs in comparison to free DOX, focusing on oxidative stress markers, inflammation, ultrastructural changes, and cardiac function. Male rats were divided into the following four groups: control, citrate Au-NPs, DOX, and DOX Au-NPs. Cardiac function was assessed using echocardiography, and oxidative stress was evaluated through Nrf2, malondialdehyde (MDA) and superoxide dismutase (SOD) levels, and the GSH/GSSG ratio. The ultrastructure of cardiac tissue was assessed by transmission electron microscopy (TEM). Rats treated with DOX Au-NPs exhibited significant cardiac dysfunction, as indicated by a reduction in fractional shortening and ejection fraction. Oxidative stress markers, including elevated MDA levels and a reduced GSH/GSSG ratio, were significantly worse in the DOX Au-NP group. SOD levels decreased, indicating compromised antioxidant defenses. Citrate Au-NPs also caused some alterations in cardiac function and ultrastructure but without other molecular alterations. DOX Au-NPs failed to mitigate cardiotoxicity, instead exacerbating oxidative stress and cardiac dysfunction. DOX Au-NPs possess cardiotoxic effects, necessitating further investigation into alternative nanoparticle formulations or therapeutic combinations to ensure both efficacy and safety in cancer treatment.

Effect of Exposure to Particulate Matter on the Ocular Surface in an Experimental Allergic Eye Disease Mouse Model

In response to the escalating concern over the effect of environmental factors on ocular health, this study aimed to investigate the impact of air pollution-associated particulate matter (PM) on ocular allergy and inflammation. C57BL/6 mice were sensitized with ovalbumin (OVA) topically and aluminum hydroxide via intraperitoneal injection. Two weeks later, the mice were challenged with OVA and exposed to PM. Three groups-naive, OVA, and OVA-sensitized with PM exposure (OVA + PM) groups-were induced to an Allergic Eye disease (AED) model. Parameters including clinical signs, histological changes, inflammatory cell infiltration, serum OVA-specific immunoglobulins E (IgE) levels, mast cells degranulation, cellular apoptosis and T-cell cytokines were studied. The results demonstrate that exposure with PM significantly exacerbates ocular allergy, evidenced by increased eye-lid edema, mast cell degranulation, inflammatory cytokines (IL-4, IL-5 and TNF-α), cell proliferation (Ki67), and serum IgE, polymorphonuclear leukocytes (PMN), and apoptosis and reduced goblet cells. These findings elucidate the detrimental impact of PM exposure on exacerbating the severity of AED. Noticeably, diminished goblet cells highlight disruptions in ocular surface integrity, while increased PMN infiltration with an elevated production of IgE signifies a systemic allergic response with inflammation. In conclusion, this study not only scientifically substantiates the association between air pollution, specifically PM, and ocular health, but also underscores the urgency for further exploration and targeted interventions to mitigate the detrimental effects of environmental pollutants on ocular surfaces.

Effects of the interaction between cold spells and fine particulate matter on mortality risk in Xining: a case-crossover study at high altitude

Background

With global climate change, the health impacts of cold spells and air pollution caused by PM2.5 are increasingly aggravated, especially in high-altitude areas, which are particularly sensitive. Exploring their interactions is crucial for public health.

Methods

We collected time-series data on meteorology, air pollution, and various causes of death in Xining. This study employed a time-stratified case-crossover design and conditional logistic regression models to explore the association between cold spells, PM2.5 exposure, and various causes of death, and to assess their interaction. We quantitatively analyzed the interaction using the relative excess odds due to interaction (REOI), attributable proportion due to interaction (AP), and synergy index (S). Moreover, we conducted stratified analyses by average altitude, sex, age, and educational level to identify potential vulnerable groups.

Results

We found significant associations between cold spells, PM2.5, and various causes of death, with noticeable effects on respiratory disease mortality and COPD mortality. We identified significant synergistic effects (REOI>0, AP > 0, S > 1) between cold spells and PM2.5 on various causes of death, which generally weakened with a stricter definition of cold spells and longer duration. It was estimated that up to 9.56% of non-accidental deaths could be attributed to concurrent exposure to cold spells and high-level PM2.5. High-altitude areas, males, the older adults, and individuals with lower educational levels were more sensitive. The interaction mainly varied among age groups, indicating significant impacts and a synergistic action that increased mortality risk.

Conclusion

Our study found that in high-altitude areas, exposure to cold spells and PM2.5 significantly increased the mortality risk from specific diseases among the older adults, males, and those with lower educational levels, and there was an interaction between cold spells and PM2.5. The results underscore the importance of reducing these exposures to protect public health.

Differential pulmonary toxicity and autoantibody formation in genetically distinct mouse strains following combined exposure to silica and diesel exhaust particles

BACKGROUND

Inhalation of airborne particulate matter, such as silica and diesel exhaust particles, poses serious long-term respiratory and systemic health risks. Silica exposure can lead to silicosis and systemic autoimmune diseases, while DEP exposure is linked to asthma and cancer. Combined exposure to silica and DEP, common in mining, may have more severe effects. This study investigates the separate and combined effects of occupational-level silica and ambient-level DEP on lung injury, inflammation, and autoantibody formation in two genetically distinct mouse strains, thereby aiming at understanding the interplay between genetic susceptibility, particulate exposure, and disease outcomes. Silica and diesel exhaust particles were administered to mice via oropharyngeal aspiration. Assessments of lung injury and host response included in vivo lung micro-computed tomography, lung function tests, bronchoalveolar lavage fluid analysis including inflammatory cytokines and antinuclear antibodies, and histopathology with particle colocalization.

RESULTS

The findings highlight the distinct effects of silica and diesel exhaust particles (DEP) on lung injury, inflammation, and autoantibody formation in C57BL/6J and NOD/ShiLtJ mice. Silica exposure elicited a well-established inflammatory response marked by inflammatory infiltrates, release of cytokines, and chemokines, alongside mild fibrosis, indicated by collagen deposition in the lungs of both C57BL/6J and NOD/ShilLtJ mice. Notably, these strains exhibited divergent responses in terms of respiratory function and lung volumes, as assessed through micro-computed tomography. Additionally, silica exposure induced airway hyperreactivity and elevated antinuclear antibody levels in bronchoalveolar lavage fluid, particularly prominent in NOD/ShiLtJ mice. Moreover, antinuclear antibodies correlated with extent of lung inflammation in NOD/ShiLTJ mice. Lung tissue analysis revealed DEP loaded macrophages and co-localization of silica and DEP particles. However, aside from contributing to airway hyperreactivity specifically in NOD/ShiLtJ mice, the ambient-level DEP did not significantly amplify the effects induced by silica. There was no evidence of synergistic or additive interaction between these specific doses of silica and DEP in inducing lung damage or inflammation in either of the mouse strains.

CONCLUSION

Mouse strain variations exerted a substantial influence on the development of silica induced lung alterations. Furthermore, the additional impact of ambient-level DEP on these silica-induced effects was minimal.

Effects of PM10 Airborne Particles from Different Regions of a Megacity on In Vitro Secretion of Cytokines by a Monocyte Line during Different Seasons

Several epidemiological studies have demonstrated that particulate matter (PM) in air pollution can be involved in the genesis or aggravation of different cardiovascular, respiratory, perinatal, and cancer diseases. This study assessed the in vitro effects of PM10 on the secretion of cytokines by a human monocytic cell line (THP-1). We compared the chemotactic, pro-inflammatory, and anti-inflammatory cytokines induced by PM10 collected for two years during three different seasons in five different Mexico City locations. MIP-1α, IP-10, MCP-1, TNF-α, and VEGF were the main secretion products after stimulation with 80 μg/mL of PM10 for 24 h. The THP-1 cells showed a differential response to PM10 obtained in the different sites of Mexico City. The PM10 from the north and the central city areas induced a higher pro-inflammatory cytokine response than those from the south. Seasonal pro-inflammatory cytokine secretion always exceeded anti-inflammatory secretion. The rainy-season-derived particles caused the lowest pro-inflammatory effects. We concluded that toxicological assessment of airborne particles provides evidence supporting their potential role in the chronic exacerbation of local or systemic inflammatory responses that may worsen the evolution of some chronic diseases.

Protective Potential of a Botanical-Based Supplement Ingredient against the Impact of Environmental Pollution on Cutaneous and Cardiopulmonary Systems: Preclinical Study

Air pollution is a growing threat to human health. Airborne pollution effects on respiratory, cardiovascular and skin health are well-established. The main mechanisms of air-pollution-induced health effects involve oxidative stress and inflammation. The present study evaluates the potential of a polyphenol-enriched food supplement ingredient comprising Lippia citriodora, Olea europaea, Rosmarinus officinalis, and Sophora japonica extracts in mitigating the adverse effects of environmental pollution on skin and cardiopulmonary systems. Both in vitro and ex vivo studies were used to assess the blend's effects against pollution-induced damage. In these studies, the botanical blend was found to reduce lipid peroxidation, inflammation (by reducing IL-1α), and metabolic alterations (by regulating MT-1H, AhR, and Nrf2 expression) in human skin explants exposed to a mixture of pollutants. Similar results were also observed in keratinocytes exposed to urban dust. Moreover, the ingredient significantly reduced pollutant-induced ROS production in human endothelial cells and lung fibroblasts, while downregulating the expression of apoptotic genes (bcl-2 and bax) in lung fibroblasts. Additionally, the blend counteracted the effect of urban dust on the heart rate in zebrafish embryos. These results support the potential use of this supplement as an adjuvant method to reduce the impact of environmental pollution on the skin, lungs, and cardiovascular tissues.

Disentangling impacts of multiple pollutants on acute cardiovascular events in New York city: A case-crossover analysis

BACKGROUND

Ambient air pollution contributes to an estimated 6.67 million deaths annually, and has been linked to cardiovascular disease (CVD), the leading cause of death. Short-term increases in air pollution have been associated with increased risk of CVD event, though relatively few studies have directly compared effects of multiple pollutants using fine-scale spatio-temporal data, thoroughly adjusting for co-pollutants and temperature, in an exhaustive citywide hospitals dataset, towards identifying key pollution sources within the urban environment to most reduce, and reduce disparities in, the leading cause of death worldwide.

OBJECTIVES

We aimed to examine multiple pollutants against multiple CVD diagnoses, across lag days, in models adjusted for co-pollutants and meteorology, and inherently adjusted by design for non-time-varying individual and aggregate-level covariates, using fine-scale space-time exposure estimates, in an exhaustive dataset of emergency department visits and hospitalizations across an entire city, thereby capturing the full population-at-risk.

METHODS

We used conditional logistic regression in a case-crossover design - inherently controlling for all confounders not varying within case month - to examine associations between spatio-temporal nitrogen dioxide (NO2), fine particulate matter (PM2.5), sulfur dioxide (SO2), and ozone (O3) in New York City, 2005-2011, on individual risk of acute CVD event (n = 837,523), by sub-diagnosis [ischemic heart disease (IHD), heart failure (HF), stroke, ischemic stroke, acute myocardial infarction].

RESULTS

We found significant same-day associations between NO2 and risk of overall CVD, IHD, and HF - and between PM2.5 and overall CVD or HF event risk - robust to all adjustments and multiple comparisons. Results were comparable by sex and race - though median age at CVD was 10 years younger for Black New Yorkers than White New Yorkers. Associations for NO2 were comparable for adults younger or older than 69 years, though PM2.5 associations were stronger among older adults.

DISCUSSION

Our results indicate immediate, robust effects of combustion-related pollution on CVD risk, by sub-diagnosis. Though acute impacts differed minimally by age, sex, or race, the much younger age-at-event for Black New Yorkers calls attention to cumulative social susceptibility.

Impacts of Indoor Dust Exposure on Human Colonic Cell Viability, Cytotoxicity and Apoptosis

INTRODUCTION

Environmental exposure to indoor dust is known to be associated with myriad health conditions, especially among children. Established routes of exposure include inhalation and non-dietary ingestion, which result in the direct exposure of gastrointestinal epithelia to indoor dust. Despite this, little prior research is available on the impacts of indoor dust on the health of human gastrointestinal tissue.

METHODS

Cultured human colonic (CCD841) cells were exposed for 24 h to standard trace metal dust (TMD) and organic contaminant dust (OD) samples at the following concentrations: 0, 10, 25, 50, 75, 100, 250, and 500 µg/mL. Cell viability was assessed using an MTT assay and protease analysis (glycyl-phenylalanyl-aminofluorocoumarin (GF-AFC)); cytotoxicity was assessed with a lactate dehydrogenase release assay, and apoptosis was assessed using a Caspase-Glo 3/7 activation assay.

RESULTS

TMD and OD decreased cellular metabolic and protease activity and increased apoptosis and biomarkers of cell membrane damage (LDH) in CCD841 human colonic epithelial cells. Patterns appeared to be, in general, dose-dependent, with the highest TMD and OD exposures associated with the largest increases in apoptosis and LDH, as well as with the largest decrements in metabolic and protease activities.

CONCLUSIONS

TMD and OD exposure were associated with markers of reduced viability and increased cytotoxicity and apoptosis in human colonic cells. These findings add important information to the understanding of the physiologic effects of indoor dust exposure on human health. The doses used in our study represent a range of potential exposure levels, and the effects observed at the higher doses may not necessarily occur under typical exposure conditions. The effects of long-term, low-dose exposure to indoor dust are still not fully understood and warrant further investigation. Future research should explore these physiological mechanisms to further our understanding and inform public health interventions.

The Road to Malignant Cell Transformation after Particulate Matter Exposure: From Oxidative Stress to Genotoxicity

In cells, oxidative stress is an imbalance between the production/accumulation of oxidants and the ability of the antioxidant system to detoxify these reactive products. Reactive oxygen species (ROS), cause multiple cellular damages through their interaction with biomolecules such as lipids, proteins, and DNA. Genotoxic damage caused by oxidative stress has become relevant since it can lead to mutation and play a central role in malignant transformation. The evidence describes chronic oxidative stress as an important factor implicated in all stages of the multistep carcinogenic process: initiation, promotion, and progression. In recent years, ambient air pollution by particulate matter (PM) has been cataloged as a cancer risk factor, increasing the incidence of different types of tumors. Epidemiological and toxicological evidence shows how PM-induced oxidative stress could mediate multiple events oriented to carcinogenesis, such as proliferative signaling, evasion of growth suppressors, resistance to cell death, induction of angiogenesis, and activation of invasion/metastasis pathways. In this review, we summarize the findings regarding the involvement of oxidative and genotoxic mechanisms generated by PM in malignant cell transformation. We also discuss the importance of new approaches oriented to studying the development of tumors associated with PM with more accuracy, pursuing the goal of weighing the impact of oxidative stress and genotoxicity as one of the main mechanisms associated with its carcinogenic potential.

Associations between airborne crude oil chemicals and symptom-based asthma

RATIONALE

The 2010 Deepwater Horizon (DWH) oil spill response and cleanup (OSRC) workers were exposed to airborne total hydrocarbons (THC), benzene, toluene, ethylbenzene, o-, m-, and p-xylenes and n-hexane (BTEX-H) from crude oil and PM2.5 from burning/flaring oil and natural gas. Little is known about asthma risk among oil spill cleanup workers.

OBJECTIVES

We assessed the relationship between asthma and several oil spill-related exposures including job classes, THC, individual BTEX-H chemicals, the BTEX-H mixture, and PM2.5 using data from the Gulf Long-Term Follow-up (GuLF) Study, a prospective cohort of 24,937 cleanup workers and 7,671 nonworkers following the DWH disaster.

METHODS

Our analysis largely focused on the 19,018 workers without asthma before the spill who had complete exposure, outcome, and covariate information. We defined incident asthma 1-3 years following exposure using both self-reported wheeze and self-reported physician diagnosis of asthma. THC and BTEX-H were assigned to participants based on measurement data and work histories, while PM2.5 used modeled estimates. We used modified Poisson regression to estimate risk ratios (RR) and 95% confidence intervals (CIs) for associations between spill-related exposures and asthma and a quantile-based g-computation approach to explore the joint effect of the BTEX-H mixture on asthma risk.

RESULTS

OSRC workers had greater asthma risk than nonworkers (RR: 1.60, 95% CI: 1.38, 1.85). Higher estimated THC exposure levels were associated with increased risk in an exposure-dependent manner (linear trend test p < 0.0001). Asthma risk also increased with increasing exposure to individual BTEX-H chemicals and the chemical mixture: A simultaneous quartile increase in the BTEX-H mixture was associated with an increased asthma risk of 1.45 (95% CI: 1.35,1.55). With fewer cases, associations were less apparent for physician-diagnosed asthma alone.

CONCLUSIONS

THC and BTEX-H were associated with increased asthma risk defined using wheeze symptoms as well as a physician diagnosis.

pH modifies the oxidative potential and peroxide content of biomass burning HULIS under dark aging

Humic-like substances (HULIS) account for a major redox-active fraction of biomass burning organic aerosols (BBOA). During atmospheric transport, fresh acidic BB-HULIS in droplets and humid aerosols are subject to neutralization and pH-modified aging process. In this study, solutions containing HULIS isolated from wood smoldering emissions were first adjusted with NaOH and NH₃ to pH values in the range of 3.6-9.0 and then aged under oxic dark conditions. Evolution of HULIS oxidative potential (OP) and total peroxide content (equivalent H₂O₂ concentration, H₂O₂eq) were measured together with the changes in solution absorbance and chemical composition. Notable immediate responses such as peroxide generation, HULIS autoxidation, and an increase in OP and light absorption were observed under alkaline conditions. Initial H₂O₂eq, OP, and absorption increased exponentially with pH, regardless of the alkaline species added. Dark aging further oxidized the HULIS and led to pH-dependent toxic and chemical changes, exhibiting an alkaline-facilitated initial increase followed by a decrease of OP and H₂O₂eq. Although highly correlated with HULIS OP, the contributions of H₂O₂eq to OP are minor but increased both with solution pH and dark aging time. Alkalinity-assisted autoxidation of phenolic compounds and quinoids with concomitant formation of H₂O₂ and other alkalinity-favored peroxide oxidation reactions are proposed here for explaining the observed HULIS OP and chemical changes in the dark. Our findings suggest that alkaline neutralization of fresh BB-HULIS represents a previously overlooked peroxide source and pathway for modifying aerosol redox-activity and composition. Additionally, these findings imply that the lung fluid neutral environment can modify the OP and peroxide content of inhaled BB-HULIS. The results also suggest that common separation protocols of HULIS using base extraction methods should be treated with caution when evaluating and comparing their composition, absorption, and relative toxicity.

Traffic-related particulate matter aggravates ocular allergic inflammation by mediating dendritic cell maturation

The aim of this study was to determine the effects of traffic-related particulate matter (PM) on allergic inflammation of ocular surfaces. BALB/c mice were sensitized with ovalbumin (OVA) and aluminum hydroxide via intraperitoneal injection. Two weeks later, mice were challenged with eye drops containing OVA concomitant with either traffic-related PM_2.5 or vehicle eye drops. Topical OVA challenges were administered following unilateral subconjunctival injection of magnetic-bead-sorted CD11c+ dendritic cells (DC). The following were assessed: (1) clinical signs, (2) infiltration of inflammatory cells into conjunctiva, (3) serum levels of OVA-specific IgE production, and (4) T-cell cytokine secretion with topical application of PM_2.5, compared to saline vehicle. PM_2.5 was found to increase production of OVA-specific IgE in serum and Th2 immune response-related cytokines including interleukin (IL)-4, IL-17A, and IL-13 compared to vehicle control. It is of interest that PM_2.5 treatment also elevated the population of mature DCs in draining lymph nodes (LNs). Exposure with PM_2.5 was associated with a significant rise in conjunctival expression of IL-1β, IL-6, IL-17, and TNF. After subconjunctival injection of CD11c+DCs from PM_2.5-treated allergic conjunctivitis (AC) mice into naïve mice, T cell responses and OVA-specific IgE were also enhanced. Data suggest that traffic-related PM_2.5 exacerbated allergic conjunctivitis as evidenced by increased infiltration of inflammatory cells into the conjunctiva and Th2 responses in the draining LNs associated with enhanced maturation of DCs. Our findings provide new insight into the hazardous potential of traffic-related PM_2.5 on allergic diseases, such as asthma or atopic dermatitis.

Airway hyperresponsiveness development and the toxicity of PM2.5

Airway hyperresponsiveness (AHR) is characterized by excessive bronchoconstriction in response to nonspecific stimuli, thereby leading to airway stenosis and increased airway resistance. AHR is recognized as a key characteristic of asthma and is associated with significant morbidity. At present, many studies on the molecular mechanisms of AHR have mainly focused on the imbalance in Th1/Th2 cell function and the abnormal contraction of airway smooth muscle cells. However, the specific mechanisms of AHR remain unclear and need to be systematically elaborated. In addition, the effect of air pollution on the respiratory system has become a worldwide concern. To date, numerous studies have indicated that certain concentrations of fine particulate matter (PM2.5) can increase airway responsiveness and induce acute exacerbation of asthma. Of note, the concentration of PM2.5 does correlate with the degree of AHR. Numerous studies exploring the toxicity of PM2.5 have mainly focused on the inflammatory response, oxidative stress, genotoxicity, apoptosis, autophagy, and so on. However, there have been few reviews systematically elaborating the molecular mechanisms by which PM2.5 induces AHR. The present review separately sheds light on the underlying molecular mechanisms of AHR and PM2.5-induced AHR.

Polycyclic aromatic hydrocarbon metabolites and mortality risk in an adult population

Occupational polycyclic aromatic hydrocarbons (PAHs) exposure has been shown to increase the risk of various cancers and may be associated with carcinogenic mortality. However, no study has explored the relationship between environmental PAH exposure and mortality in general population. The aim of our study was to explore the association between PAH exposure and all-cause, cardiovascular, and cancer mortality in a general US adult population. We analyzed data from the National Health and Nutrition Examination Survey (NHANES 2001-2006) based on the information in this dataset on 692 males and 717 females. PAH exposure was detected using biomarkers from urine samples. Follow-up data on mortality were derived from initial examination of the subjects until death or 31 December 2006 in the NHANES database. We calculated hazard ratios (HRs) of PAH metabolites among all-cause, cardiovascular, and cancer mortality using the multivariate Cox proportional hazards regression model after adjusting for covariates. Among males, 3-phenanthrene was positively associated with increased risk of all-cause mortality (HR 1.043, 95%CI 1.019-1.066). Female participants with higher 2-napthol (HR 1.043, 95%CI 1.014-1.072), 3-fluorene (HR 2.159, 95%CI 1.233-3.779), and 1-phenanthrene (HR = 1.259, 95%CI 1.070-1.481) levels had increased all-cause mortality. In addition, high 3-phenanthrene (HR 1.333, 95%CI 1.008-1.763) and 1-phenanthrene (HR 1.463, 95%CI 1.126-1.900) levels increased the risk of cardiovascular mortality. However, there were no significant findings for cancer mortality in both genders. Environmental PAH exposure among the adult population is associated with non-carcinogenic but not cancer mortality. Future studies are warranted to determine the underlying mechanisms related to these findings.

Exposure to fine particulate matter induces self-recovery and susceptibility of oxidative stress and inflammation in rat lungs

PM_2.5 induces pulmonary inflammation via oxidative stress, and this role in the lungs is widely accepted, but studies on whether oxidative stress and inflammation can self-recover and be fully restored are limited. In this study, the oxidative stress and inflammation in the lungs of rats, which were first exposed to different PM_2.5 dosages (0, 0.5, 3.0, and 15.0 mg/kg body weight) and different recovery days (0, 15, and 30 days) and then were exposed to the same PM_2.5 dosages (30 mg/kg b.w.) after 30 days of recovery, were investigated. Results showed that the activity of superoxide dismutase (SOD) was significantly inhibited, and the levels of malondialdehyde (MDA), inducible nitric oxide synthase (iNOS), tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), and interleukin-1β (IL-1β) significantly increased. These changes were accompanied with damage to the pathological structure of the rat lungs. After stopping PM_2.5 exposure, the difference between the PM_2.5 group and the control group gradually decreased with the extension of recovery time. However, when the rats were again exposed to the same dose of PM_2.5, the levels of IL-6, IL-1β, TNF-α, MDA, and iNOS were significantly increased, and the activities of SOD and GSH-Px were significantly inhibited in the high-dose group. And the high-dose group was accompanied by more severe lung pathological structural damage. Results showed that PM_2.5 could induce oxidative stress and inflammatory damage in the lungs of rats, and these damages gradually recovered as exposure ceased, but increased lung susceptibility in rats.

Assessment of pulmonary functions among traffic police personnel in Chennai city - A comparative cross-sectional study

Background:

Air pollution due to road traffic is a solemn health hazard and vehicular emissions due to huge population in the cities are the main reason for the air quality crisis. The study was conducted to assess the degree of impairment in lung function in traffic police personnel exposed to traffic pollution compared to less-exposed healthy subjects.

Materials and Methods:

This comparative cross-sectional study was conducted among 250 traffic police personnel, aged 20–55 years, working in Chennai city, as compared to a matched control group, consisting of 250 less-exposed subjects. Measurement of pulmonary function testing was done with an RMS Helio 401. Statistical analysis was carried out with R statistical software.

Results:

The traffic police personnel had significantly (P < 0.05) declined FEV1 and FEV1/FVC ratio and FEF 25–75% (L/s) as compared to controls. Traffic personnel with longer duration of exposure showed significantly (P < 0.05) reduced lung functions than those with shorter duration. We have found a significant negative correlation with all pulmonary function parameters such as FVC, FEV1, FEV1/FVC, PEFR, and FVC 25%–75% among the traffic police personnel.

Conclusion:

The impairment of pulmonary function among the traffic police personnel might be due to the effect of pollution by vehicular exhausts and they should be offered personal protective or preventive measures.

Occupational Exposure to Fine Particulate Matter (PM4 and PM2.5) during Hand-Made Cookware Operation: Personal, Indoor and Outdoor Levels

(1) Exposure of informal artisanal cookware makers to fine particles has not yet been characterized. The aim of this study was to characterize occupational exposure to fine particulate matter (PM4 and PM2.5) levels and fine particulate matter (PM2.5) elemental components; (2) Artisanal cookware makers were recruited from five cookware making sites. Exposure to fine particulate matter was measured for 17 male participants. SidePak personal aerosol monitors (AM520) were used to measure personal exposure to PM4, while a DustTrak monitor and an E-sampler were used to assess indoor and outdoor PM2.5 levels, respectively. A questionnaire was administered to capture information on demographic characteristics. The chemical characterization of indoor and outdoor PM2.5 filter mass was conducted using Wavelength Dispersive X-ray Fluorescence. Time series record of 15-min averages for indoor and outdoor PM2.5 levels were assessed; (3) The median (range) was 124 µg/m3 (23-100,000), 64 µg/m3 (1-6097) and 12 µg/m3 (4-1178), respectively, for personal PM4, indoor and outdoor PM2.5. The highest levels for many of the elemental components of PM2.5 were found in the outdoor PM2.5 filter mass and (4). The information generated during this study may assist in extending occupational health and safety strategies to artisanal cookware makers and developing targeted prevention initiatives.

Indoor, outdoor, and personal exposure to PM2.5 and their bioreactivity among healthy residents of Hong Kong

Direct evidence about associations between fine particles (PM_2.5) components and the corresponding PM_2.5 bioreactivity at the individual level is limited. We conducted a panel study with repeated personal measurements involving 56 healthy residents in Hong Kong. Fractional exhaled nitric oxide (FeNO) levels were measured from these subjects. Out of 56 subjects, 27 (48.2%) participated in concurrent outdoor, indoor, and personal PM_2.5 monitoring. Organic carbon (OC), elemental carbon (EC), particle bound-polycyclic aromatic hydrocarbons (PAHs), and phthalates were analyzed. Alteration in cell viability, lactic dehydrogenase (LDH), interleukin-6 (IL-6), and 8-isoprostane by 50 μg/mL PM_2.5 extracts was determined in A549 cells in vitro. Moderate heterogeneities were shown in PM_2.5 exposures and the corresponding PM_2.5 bioreactivity across different sample types. Associations between the analyzed components and PM_2.5 bioreactivity were assessed using the multiple regression models. Toxicological results revealed that indoor and personal exposure to OC as well as PAH compounds and their derivatives (e.g., Alkyl-PAHs, Oxy-PAHs) induced cell viability reduction and increase in levels of LDH, IL-6, and 8-isoprostane. Overall, OC in personal exposure played a dominant role in PM_2.5-induced bioreactivity. Subsequently, we examined the associations of FeNO with IL-6 and 8-isoprostane levels using mixed-effects models. The results showed that per interquartile change in IL-6 and 8-isoprostane were associated with a 6.4% (p < 0.01) and 11.1% (p < 0.01) increase in FeNO levels, respectively. Our study explored the toxicological properties of chemical components in PM_2.5 exposure, which suggested that residential indoors and personal OC and PAHs should be of great concern for human health. These findings indicated that further studies in inflammation and oxidative stress-related illnesses due to particle exposure would benefit from the assessment of in vitro PM_2.5 bioreactivity.

An observational study of the role of indoor air pollution in pets with naturally acquired bronchial/lung disease

BACKGROUND

Indoor air pollution (IAP) is an emerging issue for both human and veterinary patients under the concept of 'One Health'. The association between IAP and respiratory disease in companion animals has been reported.

OBJECTIVES

The present study investigated the relationship between quantifiable indoor air quality and clinical characteristics of naturally acquired bronchial/lung disease in pet dogs and cats.

METHODS

A total of 36 clinical cases (20 dogs and 16 cats) with naturally acquired bronchial/lung disease were prospectively recruited. Lower airway samples were collected and analysed, and clinical signs and the information from pulmonary function testing were examined. Indoor air quality was estimated by the average concentration of particles measuring ≤2.5 μm (PM2.5, μg/m3 ) and volatile organic compounds (VOC, ppm) in the animals' domestic microenvironments.

RESULTS

Exposure to IAP was not found to be correlated with the severity of clinical signs, pulmonary function changes or bronchoalveolar lavage fluid cytology in cats with bronchial/lung disease. However, a hypercellular response in canine lower airways was found to be associated with poor indoor air quality, including unacceptable indoor PM2.5 levels (>35 μg/m3 ) or increases in VOC concentration (>1 ppm) in places most commonly frequented by the dogs in the home.

CONCLUSIONS

Poor indoor air quality may exacerbate airway disease in pets and should not be ignored in modern society.

Preterm Birth among Infants Exposed to in Utero Ultrafine Particles from Aircraft Emissions

INTRODUCTION

Ambient air pollution is a known risk factor for adverse birth outcomes, but the role of ultrafine particles (UFPs) is not well understood. Aircraft-origin UFPs adversely affect air quality over large residential areas downwind of airports, but their reproductive health burden remains uninvestigated.

OBJECTIVES

This analysis evaluated whether UFPs from jet aircraft emissions are associated with increased rates of preterm birth (PTB) among pregnant mothers living downwind of Los Angeles International Airport (LAX).

METHODS

This population-based study used birth records, provided by the California Department of Public Health, to ascertain birth outcomes and a novel, validated geospatial UFP dispersion model approach to estimate in utero exposures. All mothers who gave birth from 2008 to 2016 while living within 15km of LAX were included in this analysis (N=174,186; including 15,134 PTBs).

RESULTS

In utero exposure to aircraft-origin UFPs was positively associated with PTB. The odds ratio (OR) per interquartile range (IQR) increase [9,200 particles per cubic centimeter (cc)] relative UFP exposure was 1.04 [95% confidence interval (CI): 1.02, 1.06]. When comparing the fourth quartile of UFP exposure to the first quartile, the OR for PTB was 1.14 (95% CI: 1.08, 1.20), adjusting for maternal demographic characteristics, exposure to traffic-related air pollution, and airport-related noise.

CONCLUSION

Our results suggest that emissions from aircraft play an etiologic role in PTBs, independent of noise and traffic-related air pollution exposures. These findings are of public health concern because UFP exposures downwind of airfields are common and may affect large, densely populated residential areas. https://doi.org/10.1289/EHP5732.

Current situation of polycyclic aromatic hydrocarbons (PAH) in PM2.5 in a receptor site in Mexico City and estimation of carcinogenic PAH by combining non-real-time and real-time measurement techniques

Air pollution is a public health concern. Polycyclic aromatic hydrocarbons (PAH) are ubiquitous atmospheric pollutants contained in the atmospheric aerosol. PAH in particulate matter with diameters ≤2.5 µm (PM_2.5) represent a human health risk due to their toxic properties. In this study, PAH in PM_2.5 at a receptor site of Mexico City during the dry cold season were determined. The most abundant PAH (median, 10-90th percentile, pg m^-3) were benzo[ghi]perylene (467, 291-697), followed by pyrene (427, 218-642). A decrease around 40% in the carcinogenic PAH onto PM_2.5 was calculated with respect to the same PAH measured a decade ago, at the same receptor site, despite of increase in vehicle fleet. The PAH decrease trend agrees with the decrease trend of CO, NO and NO₂, released into the air by similar emission sources than PAH. Control emissions strategies implemented by local and federal authorities are discussed. PAH analyses were carried out by non-real-time and real-time methods. The PAH non-real-time method involved PM_2.5 sampling, sample treatment and gas chromatography-mass spectrometry analysis. The PAH real-time method involved the use of a photoelectric aerosol sensor (PAS). The PAH determination by non-real time method was selective and efficient, with recoveries between 75 ± 14% and 98 ± 26%. By combining non-real-time and real-time methodologies, multivariate regression models were obtained based on PAS response, NO₂ and wind speed to estimate PAH in PM_2.5 at low-cost (r² = 0.59 to r² = 0.89). Fossil fuel combustion from vehicles was the major source around the sampling site. Diagnostic ratios (DR) based on retene, chrysene, and triphenylene, suggested biomass burning emission sources. Photo-oxidation in sunny months was observed based on benzo[a]pyrene, benzo[ghi]perylene, benz[a]anthracene, indeno[1,2,3-cd]pyrene and black carbon. The correlation analyses suggested transport of PM_2.5, O₃, BC and SO₂ to the sampling site, and local emissions of PAH, NO and CO.

Levels and ecological and health risk assessment of PM2.5-bound heavy metals in the northern part of the Persian Gulf

Bushehr, a port along the northern part of the Persian Gulf, has repeatedly encountered dust storms in recent years but there is not been a comprehensive study on the PM_2.5 contents in this region. The present study reports the characteristics and health risks of atmospheric PM_2.5-bound heavy metals (HMs) in Bushehr from December 2016 to September 2017. A total of 46 samples were analyzed, and a high volume air sampler equipped with quartz fiber filters was used for sampling. Inductively coupled plasma optical emission spectroscopy (ICP-OES) was also used for HMs analyses. Risk assessment and hazard index (HI) of these metals were computed by using USEPA's exposure parameters. The results showed that the average 24-h mass concentration of PM_2.5 ranged from 22.09 to 292.45 μg/m³. The results also indicated that 95.65 and 82.61% of the samples were higher than WHO and EPA guidelines for 24-h PM_2.5. Also there was no statistically significant relationship between wind direction and PM_2.5.The average concentration levels of seven measured metals (Cd, Co, Cr, Fe, Ni, Pb, and V) in the PM_2.5 samples were in the range of 6.03 ng/m³ to 1335.94 ng/m³, and the order of their concentration was Fe > Ni > Pb > Cr > Cd > V > Co. Principal component analysis (PCA) showed that PM_2.5-bound heavy metals were categorized in three groups. The ecological risk level of calculated metals was very significant, and the major contribution of the ecological risk was related to Cd. The highest HQ in children and adults was related to Cr, and overall HI in children was higher than adults. Also the RI values of Cr in both groups of children and adults were indicated high risk of developing cancer in human.

1,25-Dihydroxy Vitamin D3 Attenuates the Oxidative Stress-Mediated Inflammation Induced by PM2.5via the p38/NF-κB/NLRP3 Pathway

Vitamin D₃ is reported to be involved in the regulation of inflammatory processes. In this study, biomarkers related to oxidative stress and inflammation were investigated to clarify the protective effects and possible mechanism of 1,25-dihydroxy vitamin D₃ (1,25-(OH)₂D₃) on PM_2.5-induced inflammatory response. In the in vitro study using human bronchial epithelial (HBE) cells, aqueous extracts of PM_2.5 could induce oxidative damage which is characterized by significant increases in production of reactive oxygen species, malonaldehyde concentration, and protein expression of HSPA1A and HO-1. Meanwhile, PM_2.5 caused secretion of inflammatory factors (IL-6, IL-8) in the culture medium as well as phosphorylation of p38, nuclear factor-kappa B (NF-κB) inhibitor alpha (IκBα), and NF-κB p65 proteins. Increases in NLRP3 expression was also observed in HBE cells after PM_2.5 exposure. However, all these biomarkers were remarkably attenuated by a 24-h pretreatment of 1 nM 1,25-(OH)₂D₃. Furthermore, 1,25-(OH)₂D₃ also reduced transcriptional activation of NF-κB induced by PM_2.5 as indicated by a significant decrease in luciferase activity in HBE cells stably transfected with the NF-κB response element (RE)-driven luciferase reporter. Taken together, our findings provided novel experimental evidences supporting that vitamin D₃ could reduce the predominantly oxidative stress-mediated inflammation induced by PM_2.5via the p38/NF-κB/NLRP3 signaling pathway.

Toxicological evaluation of airborne particulate matter. Are cell culture technologies ready to replace animal testing?

Exposure to atmospheric particulate matter (PM) can affect human health, causing asthma, atherosclerosis, renal disease and cancer. In the last few years, outdoor air pollution has increased globally, leading to a public health emergency. Epidemiological studies have reported a correlation between the development of severe respiratory and systemic diseases and exposure to PM. To evaluate the toxic effect of PM of different origins, conventional experimental toxicological investigations have been conducted in animals; however, animal experimentation poses major ethical issues and usually differs from human conditions. As an alternative, human cell cultures are increasingly being used to investigate cellular and molecular mechanisms of PM toxicity. Although 2D cell cultures have been proven helpful, they are far from being a valid alternative to animal tests. Recently, 3D cell culture and organ-on-chip technology have provided systems that are more complex and that can be more informative for toxicity studies. In this review, the results of the 2D systems that are most frequently used for PM toxicity evaluations are summarized with a special focus on their limitations. We also examined to which extent 3D cell culture and particularly the organ-on-chip technology may overcome these limitations and represent effective tools to improve airborne PM toxicity evaluations.

Interactions between polycyclic aromatic hydrocarbons and epoxide hydrolase 1 play roles in asthma

Asthma, as one of the most common chronic diseases in children and adults, is a consequence of complex gene-environment interactions. Polycyclic aromatic hydrocarbons (PAHs), as a group of widespread environmental organic pollutants, are involved in the development, triggering and pathologic changes of asthma. Various previous studies reported the critical roles of PAHs in immune changes, oxidative stress and environment-gene interactions of asthma. EPHX1 (the gene of epoxide hydrolase 1, an enzyme mediating human PAH metabolism) had a possible association with asthma by influencing PAH metabolism. This review summarized that (1) the roles of PAHs in asthma-work as risk factors; (2) the possible mechanisms involved in PAH-related asthma-through immunologic and oxidative stress changes; (3) the interactions between PAHs and EPHX1 involved in asthma-enzymatic activity of epoxide hydrolase 1, which affected by EPHX1 genotypes/SNPs/diplotypes, could influence human PAH metabolism and people's vulnerability to PAH exposure. This review provided a better understanding of the above interactions and underlying mechanisms for asthma which help to raise public's concern on PAH control and develop strategies for individual asthma primary prevention.

Long-term exposure to ambient fine particles associated with asthma: A cross-sectional study among older adults in six low- and middle-income countries

BACKGROUND

Ambient PM_2.5 is considered harmful to the respiratory system. However, little has been shown about the long-term association between ambient PM_2.5 and asthma.

METHODS

A survey from 2007 to 2010 was conducted among adults over 50 years of age in six low- and middle- income countries (including China, India, Ghana, Mexico, Russia, and South Africa), which belonged to one part of a prospective cohort study - the Study on global AGEing and adult health. The yearly mean PM_2.5 concentrations of the residential communities of participants were estimated from remote sensing data. A mixed effects model was applied to investigate the association between ambient PM_2.5 and asthma.

RESULTS

A total of 4553 asthma patients were identified among the 29,249 participants in this study, producing a prevalence of 15.57%. For each 10 μg/m³ increase in PM_2.5, the adjusted prevalence ratio of asthma was 1.05 (95% Confidence Interval: 1.01, 1.08) after controlling for the effects of sex, age, BMI, education attainment, smoking status, alcohol consumption, and occupational exposure. Further analyses showed that males and smokers might be particularly vulnerable populations. Additionally, it was estimated that about 5.12% of the asthma cases in the study population (95% Confidence Interval: 1.44%, 9.23%) could be attributed to long-term PM_2.5 exposure.

CONCLUSION

Long-term exposure to PM_2.5 might be an important risk factor of asthma. Effective air pollution reduction measures should be taken to reduce PM_2.5 concentrations in order to reduce the associated asthma cases and disease burden.

Use of high-resolution metabolomics for the identification of metabolic signals associated with traffic-related air pollution

BACKGROUND

High-resolution metabolomics (HRM) is emerging as a sensitive tool for measuring environmental exposures and biological responses. The aim of this analysis is to assess the ability of high-resolution metabolomics (HRM) to reflect internal exposures to complex traffic-related air pollution mixtures.

METHODS

We used untargeted HRM profiling to characterize plasma and saliva collected from participants in the Dorm Room Inhalation to Vehicle Emission (DRIVE) study to identify metabolic pathways associated with traffic emission exposures. We measured a suite of traffic-related pollutants at multiple ambient and indoor sites at varying distances from a major highway artery for 12 weeks in 2014. In parallel, 54 students living in dormitories near (20 m) or far (1.4 km) from the highway contributed plasma and saliva samples. Untargeted HRM profiling was completed for both plasma and saliva samples; metabolite and metabolic pathway alternations were evaluated using a metabolome-wide association study (MWAS) framework with pathway analyses.

RESULTS

Weekly levels of traffic pollutants were significantly higher at the near dorm when compared to the far dorm (p < 0.05 for all pollutants). In total, 20,766 metabolic features were extracted from plasma samples and 29,013 from saliva samples. 45% of features were detected and shared in both plasma and saliva samples. 1291 unique metabolic features were significantly associated with at least one or more traffic indicator, including black carbon, carbon monoxide, nitrogen oxides and fine particulate matter (p < 0.05 for all significant features), after controlling for confounding and false discovery rate. Pathway analysis of metabolic features associated with traffic exposure indicated elicitation of inflammatory and oxidative stress related pathways, including leukotriene and vitamin E metabolism. We confirmed the chemical identities of 10 metabolites associated with traffic pollutants, including arginine, histidine, γ‑linolenic acid, and hypoxanthine.

CONCLUSIONS

Using HRM, we identified and verified biological perturbations associated with primary traffic pollutant in panel-based setting with repeated measurement. Observed response was consistent with endogenous metabolic signaling related to oxidative stress, inflammation, and nucleic acid damage and repair. Collectively, the current findings provide support for the use of untargeted HRM in the development of metabolic biomarkers of traffic pollution exposure and response.

Oxidative stress response to air particle pollution in a rat nutritional growth retardation model

Air pollution consisting of gases and particulate matter-(PM) represents a health problem in cities worldwide. However, air pollution does not impact equally all individuals, as children appear to be more vulnerable subpopulations. Air pollution and malnutrition are two distinct factors that have been associated with oxidative damage. Therefore, the interaction between environmental exposure and nutritional status in populations at risk needs to be explored. The aim of this study was to examine oxidative metabolism in lung, heart and liver in malnourished young rats exposed to residual oil fly ash (ROFA). A Nutritional Growth Retardation (NGR) model was developed in weanling male rats placed on a 20% restricted balanced diet for 4 weeks. Then, NGR and control rats were intranasally instilled with either ROFA (1mg/kg BW) or phosphate buffered saline (PBS). Twenty-four hr post-exposure lung, heart and liver were excised, and serum collected. ROFA induced lung and liver inflammation in control and NGR animals as evidenced by lung polymorphonuclear neutrophil (PMN) recruitment and alveolar space reduction accompanied by liver lymphocyte and binucleated hepatocyte level increase. In lung and liver, antioxidant defense mechanisms reduced lipoperoxidation. In contrast, only in NGR animals did ROFA exposure alter heart oxidative metabolism leading to lipid peroxidation. Although histological and biochemical tissue alterations were detected, no marked changes in serum liver and heart systemic biomarkers were observed. In conclusion, NGR animals responded differently to PM exposure than controls suggesting that nutritional status plays a key role in responsiveness to ambient air contaminants.

Short-term effects of airport-associated ultrafine particle exposure on lung function and inflammation in adults with asthma

BACKGROUND

Exposure to ultrafine particles (UFP, particles with aerodynamic diameter < 100 nm) is associated with reduced lung function and airway inflammation in individuals with asthma. Recently, elevated UFP number concentrations (PN) from aircraft landing and takeoff activity were identified downwind of the Los Angeles International Airport (LAX) but little is known about the health impacts of airport-related UFP exposure.

METHODS

We conducted a randomized crossover study of 22 non-smoking adults with mild to moderate asthma in Nov-Dec 2014 and May-Jul 2015 to investigate short-term effects of exposure to LAX airport-related UFPs. Participants conducted scripted, mild walking activity on two occasions in public parks inside (exposure) and outside (control) of the high UFP zone. Spirometry, multiple flow exhaled nitric oxide, and circulating inflammatory cytokines were measured before and after exposure. Personal UFP PN and lung deposited surface area (LDSA) and stationary UFP PN, black carbon (BC), particle-bound PAHs (PB-PAH), ozone (O3), carbon dioxide (CO2) and particulate matter (PM2.5) mass were measured. Source apportionment analysis was conducted to distinguish aircraft from roadway traffic related UFP sources. Health models investigated within-subject changes in outcomes as a function of pollutants and source factors.

RESULTS

A high two-hour walking period average contrast of ~34,000 particles·cm-3 was achieved with mean (std) PN concentrations of 53,342 (25,529) and 19,557 (11,131) particles·cm-3 and mean (std) particle size of 28.7 (9.5) and 33.2 (11.5) at the exposure and control site, respectively. Principal components analysis differentiated airport UFPs (PN), roadway traffic (BC, PB-PAH), PM mass (PM2.5, PM10), and secondary photochemistry (O3) sources. A standard deviation increase in the 'Airport UFPs' factor was significantly associated with IL-6, a circulating marker of inflammation (single-pollutant model: 0.21, 95% CI = 0.08-0.34; multi-pollutant model: 0.18, 0.04-0.32). The 'Traffic' factor was significantly associated with lower Forced Expiratory Volume in 1 s (FEV1) (single-pollutant model: -1.52, -2.28 to -0.77) and elevated sTNFrII (single-pollutant model: 36.47; 6.03-66.91; multi-pollutant model: 64.38; 6.30-122.46). No consistent associations were observed with exhaled nitric oxide.

CONCLUSIONS

To our knowledge, our study is the first to demonstrate increased acute systemic inflammation following exposure to airport-related UFPs. Health effects associated with roadway traffic exposure were distinct. This study emphasizes the importance of multi-pollutant measurements and modeling techniques to disentangle sources of UFPs contributing to the complex urban air pollution mixture and to evaluate population health risks.

Insights in particulate matter-induced allergic airway inflammation: Focus on the epithelium

Outdoor air pollution is a major environmental health problem throughout the world. In particular, exposure to particulate matter (PM) has been associated with the development and exacerbation of several respiratory diseases, including asthma. Although the adverse health effects of PM have been demonstrated for many years, the underlying mechanisms have not been fully identified. In this review, we focus on the role of the lung epithelium and specifically highlight multiple cytokines in PM-induced respiratory responses. We describe the available literature on the topic including in vitro studies, findings in humans (ie observations in human cohorts, human controlled exposure and ex vivo studies) and in vivo animal studies. In brief, it has been shown that exposure to PM modulates the airway epithelium and promotes the production of several cytokines, including IL-1, IL-6, IL-8, IL-25, IL-33, TNF-α, TSLP and GM-CSF. Further, we propose that PM-induced type 2-promoting cytokines are important mediators in the acute and aggravating effects of PM on airway inflammation. Targeting these cytokines could therefore be a new approach in the treatment of asthma.

Occupational exposure to asphalt mixture during road paving is related to increased mitochondria DNA copy number: a cross-sectional study

BACKGROUND

Asphalt workers are exposed to polyaromatic hydrocarbons (PAHs) from hot mix asphalt via both inhalation and dermal absorption. The use of crumb rubber modified (CRM) asphalt may result in higher exposure to PAHs and more adverse effects. Our aim is to assess occupational exposure to PAHs from conventional and CRM asphalt paving by measuring PAH metabolites in urine, and to investigate the effects on mitochondrial DNA copy number (mtDNAcn) and telomere length.

METHODS

We recruited 116 workers paving conventional asphalt, 51 workers paving CRM asphalt and 100 controls in Sweden, all males. A repeated-measures analysis included 31 workers paving both types of asphalt. Urine and blood samples were collected pre-working on Monday morning and post-working on Thursday afternoon after 4 days working. PAH metabolites: 1-hydroxypyrene (1-OH-PYR) and 2-hydroxyphenanthrene (2-OH-PH) were measured in urine by LC-MS/MS. Relative mtDNAcn and telomere length were measured by quantitative PCR.

RESULTS

Conventional and CRM asphalt workers showed higher 1-OH-PYR and 2-OH-PH than controls (p < 0.001 for all). Relative mtDNAcn were 0.21 units (p < 0.001) higher in conventional asphalt workers and 0.13 units (p = 0.010) higher in CRM asphalt workers compared to controls. Relative telomere length did not differ across occupational groups, but it was positively associated with increment of 2-OH-PH (β = 0.075, p = 0.037) in asphalt workers. The repeated-measures analysis showed no difference in either increment of 1-OH-PYP, or changes in effect biomarkers (mtDNAcn or telomere length) between paving with conventional and CRM asphalt. Increment of 2-OH-PH was smaller after paving with CRM asphalt.

CONCLUSIONS

Road asphalt paving in open areas resulted in PAHs exposure, as shown by elevation of PAH metabolites in urine. Asphalt workers may experience oxidative stress, evidenced by alternation in mtDNAcn; however the effects could not be fully explained by exposure to PAHs from the asphalt mixture.

Acacia hydaspica R. Parker ameliorates cisplatin induced oxidative stress, DNA damage and morphological alterations in rat pulmonary tissue

Background

Cisplatin (CP) drug is platinum compounds used for the treatment of various human malignancies. However, adverse outcomes related to CP restrict its usage. Acacia hydaspica is a natural shrub with various pharmacological properties. The current investigation aimed to assess the protective potential of A. hydaspica polyphenol rich ethyl acetate extract (AHE) against cisplatin (CP) induced pulmonary toxicity.

Methods

Rats were divided into six groups. Group 1 served as control (saline); Group 2 (drug control) recieved single dose of CP (7.5 mg/kg i.p.) on 1st day; Group 3 (extract control) (400 mg/kg bw, p.o.) received AHE for one week; Group 4 (Post-treated) and Group 5 (pretreated) received AHE (400 mg/kg bw/day, p.o) for 7 days after and before CP (7.5 mg/kg b.w., i.p.) respectively; Group 6 (Standard control) received silymarin (100 mg/kg b.w/7 days) before CP. At the end of dosing rats were sacrificed and pulmonary tissue samples were processed for the evaluation of antioxidant enzymes, oxidative stress markers, genotoxicity and histopathological alterations.

Results

CP caused body weights loss and increase pulmonary tissue weight. The CP significantly increases oxidative stress markers and decreases tissue antioxidant enzyme levels. Furthermore, CP induced deleterious changes in the microanatomy of pulmonary tissue by rupturing the alveolar septa, thickening of alveolar walls, and injuring the cells with subsequent collapse of blood vessels. AHE pretreatment returned MDA, NO, H₂O₂ production and improved tissue antioxidant enzyme levels to near normalcy. The histological observations evidenced that AHE effectively rescues the lungs from CP-mediated oxidative damage. CP induction in rats also caused DNA fragmentation which was restored by AHE treatment. Our results suggest that pretreatment more significantly improve CP induced deleterious effects compared with post treatment indicating protective effect. Potency of AHE pretreatment is similar to silymarin.

Conclusion

These findings demonstrated that A. hydaspica AHE extract might serve as potential adjuvant that prevents CP persuaded pulmonary toxicity due to its intrinsic antioxidant potential and polyphenolic constituents.

Ultrafine particulate matter exposure impairs vasorelaxant response in superoxide dismutase 2-deficient murine aortic rings

Studies have linked exposure to ultrafine particulate matter (PM) and adverse cardiovascular events. PM-induced oxidative stress is believed to be a key mechanism underlying observed adverse vascular effects. Advanced age is one factor known to decrease antioxidant defenses and confer susceptibility to the detrimental vascular effects seen following PM exposure. The present study was designed to investigate the vasomotor responses following ultrafine PM exposure in wild type (WT) and superoxide dismutase 2-deficient (SOD2+/-) mice that possess decreased antioxidant defense. Thoracic aortic rings isolated from young and aged WT and SOD2+/- mice were exposed to ultrafine PM in a tissue bath system. Aortic rings were then constricted with increasing concentrations of phenylephrine, followed by relaxation with rising amounts of nitroglycerin (NTG). Data demonstrated that ultrafine PM decreased the relaxation response in both young WT and young SOD2+/- mouse aortas, and relaxation was significantly reduced in young SOD2+/- compared to WT mice. Ultrafine PM significantly diminished the NTG-induced relaxation response in aged compared to young mouse aortas. After ultrafine PM exposure, the relaxation response did not differ markedly between aged WT and aged SOD2+/- mice. Data demonstrated that the greater vascular effect in aortic rings in aged mice ex vivo after ultrafine PM exposure may be attributed to ultrafine PM-induced oxidative stress and loss of antioxidant defenses in aged vascular tissue. Consistent with this conclusion is the attenuation of NTG-induced relaxation response in young SOD2+/- mice.

ABBREVIATIONS

H2O2: hydrogen peroxide; NTG: nitroglycerin; PAH: polycyclic aromatic hydrocarbons; PE: l-phenylephrine; PM: particulate matter; ROS: reactive oxygen species; SOD2: superoxide dismutase 2 deficient; WT: wild type.

Altered vulnerability to asthma at various levels of ambient Benzo[a]Pyrene by CTLA4, STAT4 and CYP2E1 polymorphisms

BACKGROUND

Within fossil- and solid-fuel dependent geographic locations, mechanisms of air pollution-induced asthma remains unknown. In particular, sources of greater genetic susceptibility to airborne carcinogen, namely, benzo[a]pyrene (B[a]P) has never been investigated beyond that of a few well known genes.

OBJECTIVES

To deepen our understanding on how the genotypic variations within the candidate genes contribute to the variability in the children's susceptibility to ambient B[a]P on doctor-diagnosed asthma.

METHODS

Clinically confirmed asthmatic versus healthy control children (aged, 7-15) were enrolled from historically polluted and rural background regions in Czech Republic. Contemporaneous ambient B[a]P concentration was obtained from the routine monitoring network. The sputum DNA was genotyped for 95 genes. B[a]P interaction with SNPs was studied by two-stage, semi-agnostic screening of 621 SNPs.

RESULTS

The median B[a]P within the highly polluted urban center was 8-times higher than that in the background region (7.8 vs. 1.1 ng/m³) during the period of investigation. Within the baseline model, which considered B[a]P exposure-only, the second tertile range was associated with a significantly reduced odds (aOR = 0.28) of asthma (95% CI, 0.16 to 0.50) compared to those at the lowest range. However, the highest range of B[a]P was associated with 3.18-times greater odds of the outcome (95% CI, 1.77 to 5.71). Within the gene-environment interaction models, joint occurrence of a high B[a]P exposure range and having a high-risk genotype at CTLA4 gene (rs11571316) was associated with 9-times greater odds (95% CI, 4.56-18.36) of the asthma diagnosis. Similarly, rs11571319 at CTLA4 and a high B[a]P exposure range was associated with a 8-times greater odds (95% CI, 3.95-14.27) of asthma diagnosis. Furthermore, having TG + GG genotypes on rs1031509 near STAT4 was associated with 5-times (95% CI, 3.03-8.55) greater odds of asthma diagnosis at the highest B[a]P range, compared to the odds at the reference range. Also CYP2E1 AT + TT genotypes (rs2070673) was associated with 5-times (95% CI, 3.1-8.8) greater odds of asthma diagnosis at the highest B[a]P exposure.

CONCLUSIONS

The children, who jointly experience a high B[a]P exposure (6.3-8.5 ng/m3) as well as susceptible genotypes in CTLA4 (rs11571316 and rs11571319), STAT4 (rs1031509), and CYP2E1 (rs2070673), respectively, are associated with a significantly greater odds of having doctor-diagnosed asthma, compared to those with neither risk factors.

Chemical composition of submicron and fine particulate matter collected in Krakow, Poland. Consequences for the APARIC project

Submicron particulate matter containing particles with an aerodynamic diameter ≤1 μm (PM1) are not monitored continuously by Environmental Protection Agencies around the World and are seldom studied. Numerous studies have indicated that people exposed to ultrafine (≤100 nm), submicron and fine particulate matter containing particles with an aerodynamic diameter ≤2.5 μm (PM2.5), can suffer from respiratory track diseases, cardiovascular, immunological or heart diseases and others. Inorganic pollutants containing redox active transition metals and small gaseous molecules, are involved in the generation of reactive oxygen and reactive nitrogen species. Inhalation of this kind of particles can affect immune-toxicity. Environmental pollution may aggravate the course of autoimmune diseases, in particular influence the mechanisms of the autoimmune system. Important factors that influence the toxicity of particulate matter, are particle size distribution, composition and concentration. This report deals with the composition of PM1 and PM2.5 fractions collected in Krakow, Poland. In spring 2015, the mean concentrations of PM1 and PM2.5 were 19 ± 14 and 27 ± 19 μg/m³, respectively. The PM2.5 fraction contained approximately 70 ± 17% of submicron particulate matter. In spring 2016, the mean concentrations of PM1 and PM2.5 were 12 ± 5 and 22 ± 12 μg/m³, respectively. The PM2.5 fraction contained approximately 60 ± 15% of submicron particulate matter. The concentrations of the elements Cl, K, Ca, Ti, Cr, Mn, Fe, Ni, Cu, Zn, Br, Rb, Sr and Pb in both fractions were determined by X-ray fluorescence spectrometry. Most of the analyzed metals had higher concentrations in the fine fraction than in the submicron one. Concentrations of V and As were below the detection limit in both fractions, whereas concentrations of Mn and Ca were below the detection limits in the PM1 fraction. The results are discussed in terms of the consequences they may have on the APARIC project presently underway in Krakow.

Comparison of inflammatory cytokine release from nasal epithelial cells of non-atopic non-rhinitic, allergic rhinitic and polyp subjects and effects of diesel exhaust particles in vitro

BACKGROUND

Although studies have reported an association between air pollutants and increased allergic airway diseases, such as allergic rhinitis and nasal polyposis, the underlying mechanisms are not fully understood. A limited number of studies have suggested that diesel exhaust particles (DEP) play a role in atopy and the pathogenesis of allergic upper airway diseases. The aim of this study was to investigate the effect of DEP on inflammatory cytokine release, and mRNA expression of transcription factors such as JNK and NF-β in primary nasal epithelial cells (NECs), in vitro.

METHODS

NECs from non-atopic, non-rhinitic subjects (controls) and patients with allergic rhinitis and nasal polyps were cultured and incubated with 0-100μg/ml DEP for 24h. ELISA and RT-PCR were used to assess the release of IL-8, GM-CSF, and RANTES, and mRNA expression for JNK and NF-κB, respectively.

RESULTS

Compared to control cells, NECs from subjects with atopic polyps released significantly greater amounts of IL-8 (median=887 vs. 176.6pg/μg cellular protein; p<0.0001) and RANTES (median=0.191 vs. 0.02pg/μg cellular protein; p<0.001). While 50μg/ml DEP induced release of RANTES in NECs from patients with allergic rhinitis, 100μg/ml DEP decreased IL-8 levels in NECs from both control and allergic rhinitic subjects. DEP did not affect mRNA expression for JNK and NF-κB from NECs of subjects with polyps.

CONCLUSIONS

NECs from subjects with various pathologies may respond differently to DEP.

Assessment of temporal variation for the risk of particulate matters on asthma hospitalization

Increased ambient concentration of particulate matters are considered as one of major causes for increased prevalence or exacerbation of asthma or asthma like symptoms. Recently, possible temporal variation in risks of PM on mortality has been suggested. We investigated short-term effect of both PM₁₀ and PM_2.5 on asthma hospitalization, and assessed temporal variation of PM risks in Seoul, Korea, 2003-2011. Generalized additive model was used to estimate PM risks on asthma hospitalization with consideration by long-term trend, influenza epidemic, day of week, meteorological factors. To assess temporal variation of PM risks, year-round PM risks were estimated. Stratified analysis by season and age-group were also conducted. Estimated RRs of PM on asthma hospitalization by an increase of 10㎍/㎥were 1.0084 (95% CI: 1.0041-1.0127) and 1.0156 (95% CI: 1.0055-1.0259) respectively with 7-days lag periods (lag06). PM_2.5 had stronger effect than PM₁₀ for all age group. Elderly group was most affected by PM. For the analysis of temporal variation of PM risks, we found increasing trend in total population and the elderly group. In the season-specific analysis, we also found increasing trend in winter for PM₁₀, and in spring for PM_2.5. PM₁₀ and PM_2.5 has adverse effect on asthma hospitalization with evidence suggesting temporal variation in PM risks. Further research will be needed to confirm the temporal variation of PM risk on asthma hospitalization, and to identify casual factors affecting this temporal variation. This study results could be evidentiary materials for establishing valid public health policies to reduce health burden or economic burden of asthma.

Comparison of normal and dusty day impacts on fractional exhaled nitric oxide and lung function in healthy children in Ahvaz, Iran

Children are the vulnerable group at risk of adverse health effects related to air pollution due to dust storm in Ahvaz. The purpose of this study was to compare the values of fractional exhaled nitric oxide (FENO) and lung functions as parameters of adverse health effects of particulate matter (PM) in dusty and normal (non-dusty) days in elementary schoolchildren. The study was conducted among elementary school students in Ahvaz. The healthy elementary schoolchildren (N = 105) were selected from different districts for FENO and lung function sampling during the dusty and normal days. The values of PM₁₀ and PM_2.5 during dusty days were higher than during normal days. Mean values of FENO during the normal and dusty days were 14.23 and 20.3 ppb, respectively, and the difference between these values was statistically significant (p < 0.05). Lung function results showed a statistically significant difference between the mean values of forced vital capacity during the dusty and normal days (p < 0.05). The results revealed a significant difference both in the values of inflammatory biomarker and in the lung function tests in dusty and normal days. Based on our results, fractional exhaled nitric oxide could be a useful short-term biomarker of particulate pollution effect coupled with spirometry.

Sex-Specific Associations between Particulate Matter Exposure and Gene Expression in Independent Discovery and Validation Cohorts of Middle-Aged Men and Women

BACKGROUND

Particulate matter (PM) exposure leads to premature death, mainly due to respiratory and cardiovascular diseases.

OBJECTIVES

Identification of transcriptomic biomarkers of air pollution exposure and effect in a healthy adult population.

METHODS

Microarray analyses were performed in 98 healthy volunteers (48 men, 50 women). The expression of eight sex-specific candidate biomarker genes (significantly associated with PM₁₀ in the discovery cohort and with a reported link to air pollution-related disease) was measured with qPCR in an independent validation cohort (75 men, 94 women). Pathway analysis was performed using Gene Set Enrichment Analysis. Average daily PM_2.5 and PM₁₀ exposures over 2-years were estimated for each participant's residential address using spatiotemporal interpolation in combination with a dispersion model.

RESULTS

Average long-term PM₁₀ was 25.9 (± 5.4) and 23.7 (± 2.3) μg/m³ in the discovery and validation cohorts, respectively. In discovery analysis, associations between PM₁₀ and the expression of individual genes differed by sex. In the validation cohort, long-term PM₁₀ was associated with the expression of DNAJB5 and EAPP in men and ARHGAP4 (p = 0.053) in women. AKAP6 and LIMK1 were significantly associated with PM₁₀ in women, although associations differed in direction between the discovery and validation cohorts. Expression of the eight candidate genes in the discovery cohort differentiated between validation cohort participants with high versus low PM₁₀ exposure (area under the receiver operating curve = 0.92; 95% CI: 0.85, 1.00; p = 0.0002 in men, 0.86; 95% CI: 0.76, 0.96; p = 0.004 in women).

CONCLUSIONS

Expression of the sex-specific candidate genes identified in the discovery population predicted PM₁₀ exposure in an independent cohort of adults from the same area. Confirmation in other populations may further support this as a new approach for exposure assessment, and may contribute to the discovery of molecular mechanisms for PM-induced health effects.

Outdoor PM2.5, Ambient Air Temperature, and Asthma Symptoms in the Past 14 Days among Adults with Active Asthma

BACKGROUND

Relationships between air quality and health are well-described, but little information is available about the joint associations between particulate air pollution, ambient temperature, and respiratory morbidity.

OBJECTIVES

We evaluated associations between concentrations of particulate matter ≤ 2.5 μm in diameter (PM2.5) and exacerbation of existing asthma and modification of the associations by ambient air temperature.

METHODS

Data from 50,356 adult respondents to the Asthma Call-back Survey from 2006-2010 were linked by interview date and county of residence to estimates of daily averages of PM2.5 and maximum air temperature. Associations between 14-day average PM2.5 and the presence of any asthma symptoms during the 14 days leading up to and including the interview date were evaluated using binomial regression. We explored variation by air temperature using similar models, stratified into quintiles of the 14-day average maximum temperature.

RESULTS

Among adults with active asthma, 57.1% reported asthma symptoms within the past 14 days, and 14-day average PM2.5 ≥ 7.07 μg/m3 was associated with an estimated 4-5% higher asthma symptom prevalence. In the range of 4.00-7.06 μg/m3 of PM2.5, each 1-μg/m3 increase was associated with a 3.4% [95% confidence interval (CI): 1.1, 5.7] increase in symptom prevalence; across categories of temperature from 1.1 to 80.5°F, each 1-μg/m3 increase was associated with increased symptom prevalence (1.1-44.4°F: 7.9%; 44.5-58.6°F: 6.9%; 58.7-70.1°F: 2.9%; 70.2-80.5°F: 7.3%).

CONCLUSIONS

These results suggest that each unit increase in PM2.5 may be associated with an increase in the prevalence of asthma symptoms, even at levels as low as 4.00-7.06 μg/m3. Citation: Mirabelli MC, Vaidyanathan A, Flanders WD, Qin X, Garbe P. 2016. Outdoor PM2.5, ambient air temperature, and asthma symptoms in the past 14 days among adults with active asthma. Environ Health Perspect 124:1882-1890; http://dx.doi.org/10.1289/EHP92.

Household Air Pollution Exposure and Influence of Lifestyle on Respiratory Health and Lung Function in Belizean Adults and Children: A Field Study

Household air pollution (HAP) contributes to the global burden of disease. Our primary purpose was to determine whether HAP exposure was associated with reduced lung function and respiratory and non-respiratory symptoms in Belizean adults and children. Our secondary purpose was to investigate whether lifestyle (physical activity (PA) and fruit and vegetable consumption (FV)) is associated with reported symptoms. Belizean adults (n = 67, 19 Male) and children (n = 23, 6 Male) from San Ignacio Belize and surrounding areas participated in this cross-sectional study. Data collection took place at free walk-in clinics. Investigators performed initial screenings and administered questionnaires on (1) sources of HAP exposure; (2) reported respiratory and non-respiratory symptoms and (3) validated lifestyle questionnaires. Participants then performed pulmonary function tests (PFTs) and exhaled breath carbon monoxide (CO). There were no significant associations between HAP exposure and pulmonary function in adults. Increased exhaled CO was associated with a significantly lower forced expiratory volume in 1-s divided by forced vital capacity (FEV₁/FVC) in children. Exposed adults experienced headaches, burning eyes, wheezing and phlegm production more frequently than unexposed adults. Adults who met PA guidelines were less likely to experience tightness and pressure in the chest compared to those not meeting guidelines. In conclusion, adults exposed to HAP experienced greater respiratory and non-respiratory symptoms, which may be attenuated by lifestyle modifications.

Latex Allergy and Sensitization in Cities: A Survey in a Population at Risk

The constant increase in allergic diseases in western countries is correlated with changes in lifestyle and with the deterioration of the air inhaled by the inhabitants because of the growing concentrations of pollutant substances present. Within a population at risk, i.e., the inhabitants of cities, a group of subjects at even higher risk was selected, whose job exposes them to automobile exhaust fumes for many hours a day. All the study subjects underwent allergological screening and spirometry. The results obtained show an overall increase of respiratory allergic diseases but no increased sensitisation to latex. It therefore seems plausible that, besides social and lifestyle changes, the deterioration of the quality of the air could be considered responsible, at least in part, for the growing numbers of allergic subjects. This study offers an opportunity to reconsider the validity of the “hygiene hypothesis” as an explanation for the increase of allergic disease in western countries, although recent reports have indicated that a sedentary lifestyle may also contribute, together with environmental degradation, to the notably increased prevalence of allergic diseases in large cities in industrialized nations.

Climate Change and Air Pollution: Effects on Respiratory Allergy

A body of evidence suggests that major changes involving the atmosphere and the climate, including global warming induced by anthropogenic factors, have impact on the biosphere and human environment. Studies on the effects of climate change on respiratory allergy are still lacking and current knowledge is provided by epidemiological and experimental studies on the relationship between allergic respiratory diseases, asthma and environmental factors, such as meteorological variables, airborne allergens, and air pollution. Urbanization with its high levels of vehicle emissions, and a westernized lifestyle are linked to the rising frequency of respiratory allergic diseases and bronchial asthma observed over recent decades in most industrialized countries. However, it is not easy to evaluate the impact of climate changes and air pollution on the prevalence of asthma in the general population and on the timing of asthma exacerbations, although the global rise in asthma prevalence and severity could also be an effect of air pollution and climate change. Since airborne allergens and air pollutants are frequently increased contemporaneously in the atmosphere, an enhanced IgE-mediated response to aeroallergens and enhanced airway inflammation could account for the increasing frequency of respiratory allergy and asthma in atopic subjects in the last 5 decades. Pollen allergy is frequently used to study the relationship between air pollution and respiratory allergic diseases, such as rhinitis and bronchial asthma. Epidemiologic studies have demonstrated that urbanization, high levels of vehicle emissions, and westernized lifestyle are correlated with an increased frequency of respiratory allergy prevalently in people who live in urban areas in comparison with people living in rural areas. Climatic factors (temperature, wind speed, humidity, thunderstorms, etc.) can affect both components (biological and chemical) of this interaction.

TRP channels and traffic-related environmental pollution-induced pulmonary disease

Environmental pollutant exposures are major risk factors for adverse health outcomes, with increased morbidity and mortality in humans. Diesel exhaust (DE) is one of the major harmful components of traffic-related air pollution. Exposure to DE affects several physiological systems, including the airways, and pulmonary diseases are increased in highly populated urban areas. Hence, there are urgent needs to (1) create newer and lesser polluting fuels, (2) improve exhaust aftertreatments and reduce emissions, and (3) understand mechanisms of actions for toxic effects of both conventional and cleaner diesel fuels on the lungs. These steps could aid the development of diagnostics and interventions to prevent the negative impact of traffic-related air pollution on the pulmonary system. Exhaust from conventional, and to a lesser extent, clean fuels, contains particulate matter (PM) and more than 400 additional chemical constituents. The major toxic constituents are nitrogen oxides (NOx) and polycyclic aromatic hydrocarbons (PAHs). PM and PAHs could potentially act via transient receptor potential (TRP) channels. In this review, we will first discuss the associations between DE from conventional as well as clean fuel technologies and acute and chronic airway inflammation. We will then review possible activation and/or potentiation of TRP vanilloid type 1 (TRPV1) and ankyrin 1 (TRPA1) channels by PM and PAHs. Finally, we will discuss and summarize recent findings on the mechanisms whereby TRPs could control the link between DE and airway inflammation, which is a primary determinant leading to pulmonary disease.

Persistent effects of Libby amphibole and amosite asbestos following subchronic inhalation in rats

Background

Human exposure to Libby amphibole (LA) asbestos increases risk of lung cancer, mesothelioma, and non-malignant respiratory disease. This study evaluated potency and time-course effects of LA and positive control amosite (AM) asbestos fibers in male F344 rats following nose-only inhalation exposure.

Methods

Rats were exposed to air, LA (0.5, 3.5, or 25.0 mg/m³ targets), or AM (3.5 mg/m³ target) for 10 days and assessed for markers of lung inflammation, injury, and cell proliferation. Short-term results guided concentration levels for a stop-exposure study in which rats were exposed to air, LA (1.0, 3.3, or 10.0 mg/m³), or AM (3.3 mg/m³) 6 h/day, 5 days/week for 13 weeks, and assessed 1 day, 1, 3, and 18 months post-exposure. Fibers were relatively short; for 10 mg/m³ LA, mean length of all structures was 3.7 μm and 1 % were longer than 20 μm.

Results

Ten days exposure to 25.0 mg/m³ LA resulted in significantly increased lung inflammation, fibrosis, bronchiolar epithelial cell proliferation and hyperplasia, and inflammatory cytokine gene expression compared to air. Exposure to 3.5 mg/m³ LA resulted in modestly higher markers of acute lung injury and inflammation compared to AM. Following 13 weeks exposure, lung fiber burdens correlated with exposure mass concentrations, declining gradually over 18 months. LA (3.3 and 10.0 mg/m³) and AM produced significantly higher bronchoalveolar lavage markers of inflammation and lung tissue cytokines, Akt, and MAPK/ERK pathway components compared to air control from 1 day to 3 months post-exposure. Histopathology showed alveolar inflammation and interstitial fibrosis in all fiber-exposed groups up to 18 months post-exposure. Positive dose trends for incidence of alveolar epithelial hyperplasia and bronchiolar/alveolar adenoma or carcinoma were observed among LA groups.

Conclusions

Inhalation of relatively short LA fibers produced inflammatory, fibrogenic, and tumorigenic effects in rats which replicate essential attributes of asbestos-related disease in exposed humans. Fiber burden, inflammation, and activation of growth factor pathways may persist and contribute to lung tumorigenesis long after initial LA exposure. Fiber burden data are being used to develop a dosimetry model for LA fibers, which may provide insights on mode of action for hazard assessment.

Electronic supplementary material

The online version of this article (doi:10.1186/s12989-016-0130-z) contains supplementary material, which is available to authorized users.

ROS-generating/ARE-activating capacity of metals in roadway particulate matter deposited in urban environment

In this study we investigated the possible causal role for soluble metal species extracted from roadway traffic emissions in promoting particulate matter (PM)-induced reactive oxygen species (ROS) production and antioxidant response element (ARE) promoter activation. To this end, these responses have been evaluated in alveolar macrophage and epithelial lung cells that have been exposed to 'Unfiltered', 'Filtered' and 'Filtered+Chelexed' water extracts of PM samples collected from the roadway urban environments of Thessaloniki, Milan and London. Except for Thessaloniki, our results demonstrate that filtration resulted in a minor decrease in ROS activity of the fine PM fraction, suggesting that ROS activity is attributed mainly to water-soluble PM species. In contrast to ROS, ARE activity was mediated predominantly by the water-soluble component of PM present in both the fine and coarse extracts. Further removal of metals by Chelex treatment from filtered water extracts showed that soluble metal species are the major factors mediating ROS and ARE activities of the soluble fraction, especially in the London PM extracts. Finally, utilizing step-wise multiple-regression analysis, we show that 87% and 78% of the total variance observed in ROS and ARE assays, respectively, is accounted for by changes in soluble metal concentration. Using a statistical analysis we find that As, Zn and Fe best predict the ROS-generating/ARE-activating capacity of the near roadway particulate matter in the pulmonary cells studied. Collectively, our findings imply that soluble metals present in roadside PM are potential drivers of both pro- and anti-oxidative effects of PM in respiratory tract.

Effects on asthma and respiratory allergy of Climate change and air pollution

The major changes to our world are those involving the atmosphere and the climate, including global warming induced by anthropogenic factors, with impact on the biosphere and human environment. Studies on the effects of climate changes on respiratory allergy are still lacking and current knowledge is provided by epidemiological and experimental studies on the relationship between allergic respiratory diseases, asthma and environmental factors, like meteorological variables, airborne allergens and air pollution. Epidemiologic studies have demonstrated that urbanization, high levels of vehicle emissions and westernized lifestyle are correlated with an increased frequency of respiratory allergy, mainly in people who live in urban areas in comparison with people living in rural areas. However, it is not easy to evaluate the impact of climate changes and air pollution on the prevalence of asthma in general and on the timing of asthma exacerbations, although the global rise in asthma prevalence and severity could be also considered an effect of air pollution and climate changes. Since airborne allergens and air pollutants are frequently increased contemporaneously in the atmosphere, enhanced IgE-mediated response to aeroallergens and enhanced airway inflammation could account for the increasing frequency of respiratory allergy and asthma in atopic subjects in the last five decades. Pollen allergy is frequently used to study the interrelationship between air pollution and respiratory allergic diseases such as rhinitis and bronchial asthma. Climatic factors (temperature, wind speed, humidity, thunderstorms, etc) can affect both components (biological and chemical) of this interaction. Scientific societies should be involved in advocacy activities, such as those realized by the Global Alliance against chronic Respiratory Diseases (GARD).