Post-Effect of Air Quality Improvement on Biomarkers for Systemic Inflammation and Microparticles in Asthma Patients After the 2008 Beijing Olympic Games: a Pilot Study

Exposure memory and susceptibility to ambient PM2.5: A perspective from hepatic cholesterol and bile acid metabolism

Both epidemiological and experimental studies increasingly show that exposure to ambient fine particulate matter (PM2.5) is related to the occurrence and development of chronic diseases, such as metabolic diseases. However, whether PM2.5 has "exposure memory" and how these memories affect chronic disease development like hepatic metabolic homeostasis are unknown. Therefore, we aimed to explore the effects of exposure transition on liver cholesterol and bile acids (BAs) metabolism in mice. In this study, C57BL/6 mice were exposed to concentrated ambient PM2.5 or filtered air (FA) in a whole-body exposure facility for an initial period of 10 weeks, followed by another 8 weeks of exposure switch (PM2.5 to FA and FA to PM2.5) comparing to non-switch groups (FA to FA and PM2.5 to PM2.5), which were finally divided into four groups (FF of FA to FA, PP of PM2.5 to PM2.5, PF of PM2.5 to FA, and FP of FA to PM2.5). Our results showed no significant difference in food intake, body composition, glucose homeostasis, and lipid metabolism between FA and PM2.5 groups after the initial exposure before the exposure switch. At the end of the exposure switch, the mice switched from FA to PM2.5 exposure exhibited a high sensitivity to late-onset PM2.5 exposure, as indicated by significantly elevated hepatic cholesterol levels and disturbed BAs metabolism. However, the mice switched from PM2.5 to FA exposure retained a certain memorial effects of previous PM2.5 exposure in hepatic cholesterol levels, cholesterol metabolism, and BAs metabolism. Furthermore, 18-week PM2.5 exposure significantly increased hepatic free BAs levels, which were completely reversed by the FA exposure switch. Finally, the changes in small heterodimeric partner (SHP) and nuclear receptor subfamily 5 group A member 2 (LRH1) in response to exposure switch mechanistically explained the above alterations. Therefore, mice switching from PM2.5 exposure to FA showed only a weak memory of prior PM2.5 exposure. In contrast, the early FA caused mice to be more susceptible to subsequent PM2.5 exposure.

Biomarkers of the relationship of particulate matter exposure with the progression of chronic respiratory diseases

A high level of particulate matter (PM) in air is correlated with the onset and development of chronic respiratory diseases. We conducted a systematic literature review, searching the MEDLINE, EMBASE, and Cochrane databases for studies of biomarkers of the effect of PM exposure on chronic respiratory diseases and the progression thereof. Thirty-eight articles on biomarkers of the progression of chronic respiratory diseases after exposure to PM were identified, four of which were eligible for review. Serum, sputum, urine, and exhaled breath condensate biomarkers of the effect of PM exposure on chronic obstructive pulmonary disease (COPD) and asthma had a variety of underlying mechanisms. We summarized the functions of biomarkers linked to COPD and asthma and their biological plausibility. We identified few biomarkers of PM exposure-related progression of chronic respiratory diseases. The included studies were restricted to those on biomarkers of the relationship of PM exposure with the progression of chronic respiratory diseases. The predictive power of biomarkers of the effect of PM exposure on chronic respiratory diseases varies according to the functions of the biomarkers.

Extracellular Vesicles (EVs) as Crucial Mediators of Cell-Cell Interaction in Asthma

Asthma is the most common chronic respiratory disorder worldwide and accounts for a huge health and economic burden. Its incidence is rapidly increasing but, in parallel, novel personalized approaches have emerged. Indeed, the improved knowledge of cells and molecules mediating asthma pathogenesis has led to the development of targeted therapies that significantly increased our ability to treat asthma patients, especially in severe stages of disease. In such complex scenarios, extracellular vesicles (EVs i.e., anucleated particles transporting nucleic acids, cytokines, and lipids) have gained the spotlight, being considered key sensors and mediators of the mechanisms controlling cell-to-cell interplay. We will herein first revise the existing evidence, mainly by mechanistic studies in vitro and in animal models, that EV content and release is strongly influenced by the specific triggers of asthma. Current studies indicate that EVs are released by potentially all cell subtypes in the asthmatic airways, particularly by bronchial epithelial cells (with different cargoes in the apical and basolateral side) and inflammatory cells. Such studies largely suggest a pro-inflammatory and pro-remodelling role of EVs, whereas a minority of reports indicate protective effects, particularly by mesenchymal cells. The co-existence of several confounding factors-including technical pitfalls and host and environmental confounders-is still a major challenge in human studies. Technical standardization in isolating EVs from different body fluids and careful selection of patients will provide the basis for obtaining reliable results and extend their application as effective biomarkers in asthma.

Blood-Based Biomarkers for Eosinophilic Esophagitis and Concomitant Atopic Diseases: A Look into the Potential of Extracellular Vesicles

Eosinophilic esophagitis (EoE) is a chronic, Th2-inflammatory disease of the esophagus that can severely affect food intake. Currently, diagnosis and assessing response to treatment of EoE is highly invasive and requires endoscopy with esophageal biopsies. Finding non-invasive and accurate biomarkers is important for improving patient well-being. Unfortunately, EoE is usually accompanied by other atopies, which make it difficult to identify specific biomarkers. Providing an update of circulating EoE biomarkers and concomitant atopies is therefore timely. This review summarizes the current knowledge in EoE blood biomarkers and two of its most common comorbidities, bronchial asthma (BA) and atopic dermatitis (AD), focusing on dysregulated proteins, metabolites, and RNAs. It also revises the current knowledge on extracellular vesicles (EVs) as non-invasive biomarkers for BA and AD, and concludes with the potential use of EVs as biomarkers in EoE.

The impact of environmental contaminants on extracellular vesicles and their key molecular regulators: A literature and database-driven review

Exposure to environmental chemicals is now well recognized as a significant factor contributing to the global burden of disease; however, there remain critical gaps in understanding the types of biological mechanisms that link environmental chemicals to adverse health outcomes. One type of mechanism that remains understudied involves extracellular vesicles (EVs), representing small cell-derived particles capable of carrying molecular signals such as RNAs, miRNAs, proteins, lipids, and chemicals through biological fluids and imparting beneficial, neutral, or negative effects on target cells. In fact, evidence is just now starting to grow that supports the role of EVs in various disease etiologies. This review aims to (1) Provide a landscape of the current understanding of the functional relationship between EVs and environmental chemicals; (2) Summarize current knowledge of EV regulatory processes including production, packaging, and release; and (3) Conduct a database-driven analysis of known chemical-gene interactions to predict and prioritize environmentally relevant chemicals that may impact EV regulatory genes and thus EV regulatory processes. This approach to predicting environmentally relevant chemicals that may alter EVs provides a novel method for evidence-based hypothesis generation for future studies evaluating the link between environmental exposures and EVs.

Exosomes in chronic respiratory diseases

Exosomes are nano-sized vesicles released by almost all cell types, with a central role as mediators of intercellular communication. In addition to physiological conditions, these extracellular vesicles seem to play a pivotal role in inflammatory processes. This assumption offers the opportunity to study exosomes as promising biomarkers and therapeutic tools for chronic respiratory disorders. Indeed, although it is well-known that at the basis of conditions like asthma, chronic obstructive pulmonary disease, alpha-1 antitrypsin deficiency and idiopathic pulmonary fibrosis there is a dysregulated inflammatory process, an unequivocal correlation between different phenotypes and their pathophysiological mechanisms has not been established yet. In this review, we report and discuss some of the most significant studies on exosomes from body fluids of subjects affected by airway diseases. Furthermore, the most widespread techniques for exosome isolation and characterization are described. Further studies are needed to answer the unresolved questions about the functional link between exosomes and chronic respiratory diseases.

The benefits of a systematic assessment of respiratory health in illness-susceptible athletes

Respiratory tract illness is a leading cause of training and in-competition time loss in elite athletes. Asthma is known to be prevalent in athletes, but the coexistence of other respiratory problems in those deemed to be susceptible to respiratory tract illness is unknown. The aim of this study was to apply a comprehensive prospective approach to identify respiratory problems and explore relationships in athletes with heightened respiratory illness susceptibility.UK World Class Performance Programme athletes prospectively completed a systematic review of respiratory health with validated questionnaires and respiratory-focused investigations, including studies of nasal flow, exhaled nitric oxide, spirometry, bronchoprovocation testing and allergy testing.Systematic respiratory health assessment was completed by 122 athletes (55 females, mean±sd age 24±4 years). At least one respiratory health issue, requiring intervention, was identified in 97 (80%) athletes and at least two abnormalities were found in 73 (60%). Sinonasal problems were the most commonly identified problem (49%) and 22% of athletes had a positive indirect bronchoprovocation test. Analysis revealed two respiratory health clusters: 1) asthma, sinus problems and allergy; and 2) laryngeal and breathing pattern dysfunction. Respiratory illness susceptible athletes had 3.6±2.5 episodes in the year prior to assessment and were more likely to have allergy (OR 2.6, 95% CI 1.0-6.5), sinonasal problems (2.6, 1.1-6.0) and symptoms of laryngeal (5.4, 1.8-16.8) and breathing pattern dysfunction (3.9, 1.1-14.0) than nonsusceptible athletes (all p<0.05).A systematic approach to respiratory assessment identifies a high prevalence and coexistence of multiple respiratory problems in illness-susceptible athletes.

Extracellular Vesicles and Asthma-More Than Just a Co-Existence

Extracellular vesicles (EVs) are membranous structures, which are secreted by almost every cell type analyzed so far. In addition to their importance for cell-cell communication under physiological conditions, EVs are also released during pathogenesis and mechanistically contribute to this process. Here we summarize their functional relevance in asthma, one of the most common chronic non-communicable diseases. Asthma is a complex persistent inflammatory disorder of the airways characterized by reversible airflow obstruction and, from a long-term perspective, airway remodeling. Overall, mechanistic studies summarized here indicate the importance of different subtypes of EVs and their variable cargoes in the functioning of the pathways underlying asthma, and show some interesting potential for the development of future therapeutic interventions. Association studies in turn demonstrate a good diagnostic potential of EVs in asthma.

Maternal immune response and air pollution exposure during pregnancy: insights from the Early Markers for Autism (EMA) study

BACKGROUND

Perinatal exposure to air pollution and immune system dysregulation are two factors consistently associated with autism spectrum disorders (ASD) and other neurodevelopmental outcomes. However, little is known about how air pollution may influence maternal immune function during pregnancy.

OBJECTIVES

To assess the relationship between mid-gestational circulating levels of maternal cytokines/chemokines and previous month air pollution exposure across neurodevelopmental groups, and to assess whether cytokines/chemokines mediate the relationship between air pollution exposures and risk of ASD and/or intellectual disability (ID) in the Early Markers for Autism (EMA) study.

METHODS

EMA is a population-based, nested case-control study which linked archived maternal serum samples collected during weeks 15-19 of gestation for routine prenatal screening, birth records, and Department of Developmental Services (DDS) records. Children receiving DDS services for ASD without intellectual disability (ASD without ID; n = 199), ASD with ID (ASD with ID; n = 180), ID without ASD (ID; n = 164), and children from the general population (GP; n = 414) with no DDS services were included in this analysis. Serum samples were quantified for 22 cytokines/chemokines using Luminex multiplex analysis technology. Air pollution exposure for the month prior to maternal serum collection was assigned based on the Environmental Protection Agency's Air Quality System data using the maternal residential address reported during the prenatal screening visit.

RESULTS

Previous month air pollution exposure and mid-gestational maternal cytokine and chemokine levels were significantly correlated, though weak in magnitude (ranging from - 0.16 to 0.13). Ten pairs of mid-pregnancy immune markers and previous month air pollutants were significantly associated within one of the child neurodevelopmental groups, adjusted for covariates (p < 0.001). Mid-pregnancy air pollution was not associated with any neurodevelopmental outcome. IL-6 remained associated with ASD with ID even after adjusting for air pollution exposure.

CONCLUSION

This study suggests that maternal immune activation is associated with risk for neurodevelopmental disorders. Furthermore, that prenatal air pollution exposure is associated with small, but perhaps biologically relevant, effects on maternal immune system function during pregnancy. Additional studies are needed to better evaluate how prenatal exposure to air pollution affects the trajectory of maternal immune activation during pregnancy, if windows of heightened susceptibility can be identified, and how these factors influence neurodevelopment of the offspring.

The association between long-term fine particulate air pollution and life expectancy in China, 2013 to 2017

BACKGROUND

China is experiencing one of the worst air quality problems in the world. China implemented the Air Pollution Prevention and Control Action Plan (APPCAP) and the air quality has recently achieved remarkable improvement.

OBJECTIVE

To evaluate the associations of variations in annual fine particulate matter (PM_2.5) levels and changes in life expectancy in Chinese urban populations from 2013 to 2017.

METHOD

We collected annual-average concentrations of PM_2.5 and average life expectancy of urban residents in 214 cities from 2013 to 2017. We conducted a longitudinal panel analysis applying linear mixed-effect models to evaluate the association between PM_2.5 reduction and life expectancy increase with and without adjustment for socioeconomic and medical-care confounders.

RESULT

The nationwide-average annual PM_2.5 concentrations decreased from 67.78 μg/m³ in 2013 to 45.25 μg/m³ in 2017; meanwhile, the average life expectancy of urban residents increased from 78.53 to 79.86 years. A decrease of 10 μg/m³ in PM_2.5 was associated with an increment of 0.18 (95% confidence interval: 0.06, 0.30) year in life expectancy. After simultaneously adjusting for GDP per capita, smoking prevalence, urbanization rate and maternal mortality, the association turned to be insignificant at the national level, but remained significant in the eastern region with life expectancy gained 0.16 (95% CI: 0.04, 0.27) year per 10 μg/m³ reduction of PM_2.5.

CONCLUSION

Lower PM_2.5 air pollution might be associated with extended life expectancy in east of China. The implementation of APPCAP during 2013 to 2017 might have resulted in benefits on life expectancy, especially in east of China.

Environmental Effective Assessment of Control Measures Implemented by Clean Air Action Plan (2013–2017) in Beijing, China

The Beijing government initiated the Clean Air Action Plan (CAAP) in 2013. Through a series of actions to control air pollution, the emissions of major atmospheric pollutants are reduced to improve urban air quality. In order to evaluate the effectiveness of control measures taken to mitigate atmospheric pollution, we investigated and analyzed the implementation of the CAAP in Beijing from 2013 to 2017, estimating the corresponding reduction in emissions of major air pollutants. The contribution of different control measures to the improvement of air quality was quantified and the experiences of managing air pollution were summarized, which provided references for the continuous improvement of air quality in Beijing and the surrounding areas. The results showed that the emission of SO2, NOX, PM10, PM2.5, and VOCs from air pollution source have been decreased by 119,924, 116,091, 116,810, 46,652, and 97,267 tons after the implementation of the CAAP. The sum of these five air pollutants emissions have been reduced by 39% in 2017 compared with 2013, the largest decrease in SO2 emissions was 87%, which was related to the vigorous control on coal-fired combustion. The control measure with the greatest contribution to decreasing the ambient PM2.5 concentration was the clean energy transformation of coal-fired power plants, which contributed 27% of the total reduced concentration and 6.1 μg/m3 of the average PM2.5 concentration reduction in Beijing. Clean Residential coal use also significantly decreased the PM2.5 concentration by 5.4 μg/m3, which was 23% of the total reduction. In addition, the industrial restructuring and the management of automotive vehicle use and dust could also contribute to efficiently reducing the PM2.5 concentration by 4.0, 3.2, and 2.3 μg/m3, or 17%, 14%, and 10% of the total reduction, respectively. Due to the implementation of control measures of Clean Air Action Plan, the energy and industrial structure of Beijing have been adjusted and optimized, leading to the reduction of pollutant emissions, which is the secret of urban long-term air quality improvement.

Extracellular vesicles and asthma: A review of the literature

Asthma is a chronic, recurrent and incurable allergy-related respiratory disease characterized by inflammation, bronchial hyperresponsiveness and narrowing of the airways. Extracellular vesicles (EVs) are a universal feature of cellular function and can be detected in different bodily fluids. Recent evidence has shown the possibility of using EVs in understanding the pathogenesis of asthma, including their potential as diagnostic and therapeutic tools. Studies have reported that EVs released from key cells involved in asthma can induce priming and activation of other asthma-associated cells. A literature review was conducted on all current research regarding the role and function of EVs in the pathogenesis of asthma via the PRISMA statement method. An electronic search was performed using EMBASE and PubMed through to November 2018. The EMBASE search returned 76 papers, while the PubMed search returned 211 papers. Following duplicate removal, titles and abstracts were screened for eligibility with a total of 34 studies included in the final qualitative analysis. The review found evidence of association between the presence of EVs and physiological changes characteristic of asthma, suggesting that EVs are involved in the pathogenesis, with the weight of evidence presently favouring deleterious effects of EVs in asthma. Numerous studies highlighted differences in exosomal contents between EVs of healthy and asthmatic individuals, which could be employed as potential diagnostic markers. In some circumstances, EVs were also found to be suppressive to disease, but more often promote inflammation and airway remodelling. In conclusion, EVs hold immense potential in understanding the pathophysiology of asthma, and as diagnostic and therapeutic markers. While more research is needed for definitive conclusions and their application in medical practice, the literature presented in this review should encourage further research and discovery within the field of EVs and asthma.

Outdoor Endurance Training with Air Pollutant Exposure Versus Sedentary Lifestyle: A Comparison of Airway Immune Responses

Although regular exercise-training improves immune/inflammatory status, the influence of air pollutants exposure during outdoor endurance training compared to a sedentary lifestyle has not yet been clarified. This study aimed to compare the immune/inflammatory responses in the airways of street runners and sedentary people after acute and chronic particulate matter (PM) exposure. Forty volunteers (street runners (RUN, n = 20); sedentary people (SED, n = 20)) were evaluated 1 (acute) and 10 (chronic) weeks after PM exposure. Cytokines [interferon (IFN)-γ, tumor necrosis factor (TNF)-α, interleukin (IL)-6, IL-10, IL-13, and IL-17A] in nasal lavage fluid, salivary antibacterial peptides (lactoferrin (LTF), cathelicidin (LL-37), defensin-α 1-3), and secretory immunoglobulin A (SIgA), plasma club cell protein (CC16), and fractional exhaled nitric oxide (FeNO) were analyzed. After acute exposure, the RUN group showed lower levels of IL-13, IL-10, and FeNO, but higher defensin-α than the SED group. After chronic exposure, the RUN group showed elevation of IFN-γ, IL-10, IL-17A, and a decrease of FeNO levels, whereas the SED group showed elevation of TNF-α, IL-6, IL-10, and a decrease of IL-13 levels. Comparing these groups, the RUN group showed higher levels of SIgA and LTF, and lower FeNO levels than the SED group. In relation to the Th immune response analysis after acute and chronic PM exposure, the RUN group showed a pattern associated with Th1, while in the SED group, a Th2 pattern was found. Both groups showed also a Th17 immune response pattern. Our results allow us to suggest that the immune/inflammatory status of the respiratory tract after acute and chronic PM exposure was improved by the long-standing regular practice of outdoor endurance exercise compared to a sedentary lifestyle.

Spatio-Temporal Variations of Multiple Primary Air Pollutants Emissions in Beijing of China, 2006–2015

Air pollution in Beijing, China has attracted continuous worldwide public attention along with the rapid urbanization of the city. By implementing a set of air pollution mitigation measures, the air quality of Beijing has been gradually improved in recent years. In this study, the intrinsic factors leading to air quality improvement in Beijing are studied via a quantitative evaluation of the temporal and spatial changes in emissions of primary air pollutants over the past ten years. Based on detailed activity levels of each economic sector and a localized database containing source and pollutant specific emission factors, an integrated emissions inventory of primary air pollutants discharged from various sources between 2006 and 2015 is established. With the implementation of phased air pollution mitigation measures, and the Clean Air Action Plan, the original coal-dominated energy structure in Beijing has undergone tremendous changes, resulting in the substantial reduction of multiple air pollutants. The total of emissions of six major atmospheric pollutants (PM10, PM2.5, SO2, NOX, VOCs and NH3) in Beijing decreased by 35% in 2015 compared to 2006—this noticeable decrease was well consistent with the declining trend of ambient concentration of criterion air pollutants (SO2, PM10, PM2.5 and NO2) and air quality improvement, thus showing a good correlation between the emission of air pollutants and the outcome of air quality. SO2 emission declined the most, at about 71.7%, which was related to the vigorous promotion of combustion source control, such as the shutdown of coal-fired facilities and domestic stoves and transition to clean energy, like natural gas or electricity. Emissions of PM decreased considerably (by 48%) due to energy structure optimization, industrial structure adjustments, and end-of-pipe PM source control. In general, NOX, NH3, and VOCs decreased relatively slightly, by 25%, 14%, and 2%, respectively, and accordingly, they represented the limiting factors for improving air quality and the key points of air pollution mitigation in Beijing for the future.

Quantitative Analysis of Health Risk Perception, Exposure Levels, and Willingness to Pay/Accept of PM2.5 during the 2014 Nanjing Youth Olympic Games

Local governments in China regularly implement short-term emission control measures to improve air quality during important sporting events. As a condition for hosting the 2014 Youth Olympic Games (YOG), the Nanjing government agreed to temporarily and substantially improve air quality. Regression analysis, Spearman correlation analysis, χ² test, and the contingent valuation method were used to explore the effects of robust, short-term air pollution control measures on risk perception, daily exposure to PM_2.5, risk acceptance levels, and willingness to pay/accept (WTP/WTA) for reductions in air pollution for the benefit of reducing health risks. Postimplementation, the respondents' risk perception levels presented the following changes: during the YOG, the respondents perceived the lowest effects of haze pollution while after the YOG, they perceived the highest effects. The changes in risk acceptance levels showed the same tendency. Furthermore, after the YOG, the respondents asked for the most economic compensation, and their willingness to pay for risk reduction also reached the highest level. This study reveals the need to increase the public's understanding of the health risks of air pollution, protect those populations most exposed to high levels of PM_2.5, and take more effective long-term measures to meet local residents' demands for improved air quality.