Chronic air pollution-induced subclinical airway inflammation and polygenic susceptibility

The impact of air pollution on influenza incidence in high-altitude regions: a time-stratified case-crossover study based on Qinghai Province

BACKGROUND

The unique characteristics of air pollution in high-altitude regions may significantly influence the transmission and incidence of influenza. However, current research on this phenomenon is limited, and further investigation is urgently needed.

METHODS

This study collected influenza outpatient data from Qinghai Province between January 1, 2016, and December 31, 2021. We employed a time-stratified case-crossover design combined with conditional Poisson regression models to quantitatively analyze the relationship between air pollutants (PM2.5, SO2, NO2) and influenza incidence and explored the moderating role of temperature in this relationship. Additionally, stratified analyses were conducted to identify potential vulnerable populations.

RESULTS

The study results indicated that exposure to PM2.5, SO2, and NO2 was positively associated with the risk of influenza incidence. For every 10 µg/m³ increase in the concentration of PM2.5, SO2, and NO2, the percentage change in relative risk (RR) of influenza incidence was 0.35% (95% CI: 0.02%, 0.68%), 2.24% (95% CI: 1.42%, 3.06%), and 1.91% (95% CI: 1.16%, 2.67%), respectively. Under low-temperature conditions, the impact of pollutants other than O3 on influenza incidence was particularly pronounced. Children, the elderly, and individuals living at altitudes of 3000-3500 m were more sensitive to these pollutants.

CONCLUSION

This study revealed a close link between air pollution and influenza in high-altitude regions, with greater health risks under low-temperature conditions. The findings underscore the necessity of strengthening air quality monitoring and raising public awareness of environmental health.

Impact of Short-Term Diesel Exhaust Exposure on Prothrombotic Markers in Chronic Obstructive Pulmonary Disease: A Randomized, Double-Blind, Crossover Study

Rationale: Growing evidence suggests that air pollution exposure is a major risk factor in chronic obstructive pulmonary disease (COPD) that is associated with an increased prothrombotic state and adverse cardiovascular outcomes. However, much of this work is based on observational data or human exposure studies involving younger participants. The biological causality and mechanism of air pollution-induced prothrombotic response in patients with COPD remain to be explored. Objectives: The main aim of this work was to investigate the impact of short-term diesel exhaust (DE) exposure on circulating prothrombotic markers-fibrinogen and plasminogen activator inhibitor-1 (PAI-1)-and urinary eicosanoids in patients with COPD. Methods: Twenty-nine research participants were recruited in this randomized, double-blind, crossover, controlled human exposure study to DE. Participants included former smokers with and without mild or moderate COPD (ex-smokers [ES] and COPD group) and healthy never-smokers without COPD (nonsmoker [NS] group). Each participant was exposed to DE (300 μg/m3 of particulate matter with an aerodynamic diameter ≤2.5 μm) and filtered air for 2 hours on different occasions, in randomized order, separated by a 4-week washout. Blood and urine samples were collected before and 24 hours after each exposure. Plasma fibrinogen and serum PAI-1 concentrations were quantified using enzyme-linked immunosorbent assays. Urinary eicosanoid concentrations were quantified using ultraperformance liquid chromatography coupled to tandem mass spectrometry. Linear mixed-effects models were used for statistical comparisons. Results: Participants with COPD showed an increase in plasma fibrinogen (effect estimate, 1.27 [1.06-1.53]; P = 0.01) after DE relative to filtered air, but no significant DE-associated change in serum PAI-1 (0.95 [0.87-1.04]; P = 0.26). In never-smokers and ex-smokers without COPD, fibrinogen (NS group, 1.10 [0.99-1.23]; P = 0.08; ES group, 0.86 [0.68-1.09]; P = 0.08] and PAI-1 (NS group, 1.12 [0.96-1.32]; P = 0.15; ES group, 0.90 [0.79-1.03]; P = 0.13) were not changed after DE exposure. Participants with COPD showed a DE-attributable increase in urinary thromboxane B2 (TXB2) metabolite concentrations as follows: 11-dehydro-TXB2 (1.45 [1.02-2.08]; P = 0.04) and 2,3-dinor-TXB2 (1.45 [1.05-2.00]; P = 0.03). Conclusions: Participants with COPD had increased plasma fibrinogen and urinary TXB2 metabolites after short-term DE exposure, suggesting they may be more susceptible to a pollution-attributable prothrombotic response than healthy control subjects or ex-smokers without COPD. Clinical trial registered with www.clinicaltrials.gov (NCT02236039).

High altitude air pollution and respiratory disease: Evaluating compounded exposure events and interactions

Today, air pollution remains a significant issue, particularly in high-altitude areas where its impact on respiratory disease remains incompletely explored. This study aims to investigate the association between various air pollutants and outpatient visits for respiratory disease in such regions, specifically focussing on Xining from 2016 to 2021. By analysing over 570,000 outpatient visits using a time-stratified case-crossover design and conditional logistic regression, we assessed the independent effects of pollutants like PM2.5, PM10, SO2, NO2, and CO, as well as their interactions. The evaluation of interactions employed measures such as relative excess odds due to interaction (REOI), attributable proportion due to interaction (AP), and synergy index (S). We also conducted a stratified analysis to identify potentially vulnerable populations. Our findings indicated that exposure to PM2.5, PM10, SO2, NO2, and CO significantly increased outpatient visits for respiratory disease, with odds ratios (ORs) of 2.40 % (95 % CI: 2.05 %, 2.74 %), 1.07 % (0.98 %, 1.16 %), 3.86 % (3.23 %, 4.49 %), 4.45 % (4.14 %, 4.77 %), and 6.37 % (5.70 %, 7.04 %), respectively. However, exposure to O3 did not show a significant association. We found significant interactions among PM2.5, SO2, NO2, and CO, where combined exposure further exacerbated the risk of respiratory diseases. For example, in the combination of PM2.5 and SO2, the REOI, AP, and S were 0.07 (95 % CI: 0.06, 0.09), 0.07 (0.06, 0.07), and 1.07 (1.05, 1.09), respectively. Additionally, elderly individuals and females were more sensitive to these pollutants, but no statistically significant interaction effects were observed between different age and gender groups. In conclusion, our study highlights the strong link between air pollution and respiratory disease in high-altitude areas, with combined pollutant exposure posing an even greater risk. It underscores the need for enhanced air quality monitoring and public awareness campaigns, particularly to protect vulnerable populations like the elderly and females.

The relationship between air pollutants and preterm birth and blood routine changes in typical river valley city

OBJECTIVE

To collect maternal maternity information on preterm births in two tertiary hospitals in the urban area of Baota District, Yan'an City, from January 2018 to December 2020, to explore the long-term and short-term effects of air pollutants (PM2.5, PM10, SO2, NO2, CO and O3) and preterm births, and to explore changes in blood cell counts due to air pollutants.

METHODS

Daily average mass concentration data of six air pollutants in the urban area of Yan'an City from January 1, 2017 to December 31, 2020 were collected from the monitoring station in Baota District, Yan'an City. Meteorological information was obtained from the Meteorological Bureau of Yan'an City, including temperature,relative humidity and wind speed for the time period. The mass concentration of air pollutants in each exposure window of pregnant women was assessed by the nearest monitoring station method, and conditional logistic regression was used to analyze the relationship between air pollutants and preterm births, as well as the lagged and cumulative effects of air pollutants. Multiple linear regression was used to explore the relationship between air pollutants and blood tests after stepwise linear regression was used to determine confounders for each blood test.

RESULTS

The long-term effects of pollutants showed that PM2.5, PM10, SO2, NO2and CO were risk factors for preterm birth. In the two-pollutant model, PM2.5, PM10, SO2 and NO2 mixed with other pollutants were associated with preterm birth. The lagged effect showed that PM2.5, PM10, SO2, NO, and CO were associated with preterm birth; the cumulative effect showed that other air pollutants except O3 were associated with preterm birth. The correlation study between air pollutants and blood indicators showed that air pollutants were correlated with leukocytes, monocytes, basophils, erythrocytes, hs-CRPand not with CRP.

CONCLUSION

Exposure to air pollutants is a risk factor for preterm birth. Exposure to air pollutants was associated with changes in leukocytes, monocytes, basophils and erythrocytes and hs-CRP.

Determining the toxicological effects of indoor air pollution on both a healthy and an inflammatory-comprised model of the alveolar epithelial barrier in vitro

Exposure to indoor air pollutants (IAP) has increased recently, with people spending more time indoors (i.e. homes, offices, schools and transportation). Increased exposures of IAP on a healthy population are poorly understood, and those with allergic respiratory conditions even less so. The objective of this study, therefore, was to implement a well-characterised in vitro model of the human alveolar epithelial barrier (A549 + PMA differentiated THP-1 incubated with and without IL-13, IL-5 and IL-4) to determine the effects of a standardised indoor particulate (NIST 2583) on both a healthy lung model and one modelling a type-II (stimulated with IL-13, IL-5 and IL-4) inflammatory response (such as asthma).Using concentrations from the literature, and an environmentally appropriate exposure we investigated 232, 464 and 608ng/cm2 of NIST 2583 respectively. Membrane integrity (blue dextran), viability (trypan blue), genotoxicity (micronucleus (Mn) assay) and (pro-)/(anti-)inflammatory effects (IL-6, IL-8, IL-33, IL-10) were then assessed 24 h post exposure to both models. Models were exposed using a physiologically relevant aerosolisation method (VitroCell Cloud 12 exposure system).No changes in Mn frequency or membrane integrity in either model were noted when exposed to any of the tested concentrations of NIST 2583. A significant decrease (p < 0.05) in cell viability at the highest concentration was observed in the healthy model. Whilst cell viability in the "inflamed" model was decreased at the lower concentrations (significantly (p < 0.05) after 464ng/cm2). A significant reduction (p < 0.05) in IL-10 and a significant increase in IL-33 was seen after 24 h exposure to NIST 2583 (464, 608ng/cm2) in the "inflamed" model.Collectively, the results indicate the potential for IAP to cause the onset of a type II response as well as exacerbating pre-existing allergic conditions. Furthermore, the data imposes the importance of considering unhealthy individuals when investigating the potential health effects of IAP. It also highlights that even in a healthy population these particles have the potential to induce this type II response and initiate an immune response following exposure to IAP.

Acute exposure to realistic simulated urban atmospheres exacerbates pulmonary phenotype in cystic fibrosis-like mice

Cystic Fibrosis (CF) is a lethal genetic disorder caused by pathogenic mutations of the CFTR gene. CF patients show a high phenotypic variability of unknown origin. In this context, the present study was therefore dedicated to investigating the effects of acute exposure to air pollution on the pulmonary morbidity of a CF-like mice model. To achieve our aim, we developed a multidisciplinary approach and designed an innovative protocol using a simulation chamber reproducing multiphasic chemical processes at the laboratory. A particular attention was paid to modulate the composition of these simulated atmospheres, in terms of concentrations of gaseous and particulate pollutants. Exposure to simulated urban atmospheres induced mucus secretion and increased inflammatory biomarkers levels, oxidative stress as well as expression of lung remodeling actors in both WT and CF-like mice. The latter were more susceptible to develop such a response. Though we could not establish direct mechanistic link between biological responses and specific components, the type of immune response induced depended on the chemical composition of the atmospheres. Overall, we demonstrated that air pollution is an important determinant of CF-like lung phenotypic variability and emphasized the added value of considering air pollution with a multi-pollutant approach.