Longitudinal study of respiratory function and symptoms in a non-smoking group of long-term officially-acknowledged victims of pollution-related illness

Acute exposure to seasonal PM2.5 induces toxicological responses in A549 cells cultured at the air-liquid interface mediated by oxidative stress and endoplasmic reticulum stress

Atmospheric fine particulate matter (PM2.5) enters the human body through respiration and poses a threat to human health. This is not only dependent on its mass concentration in the atmosphere, but also related to seasonal variations in its chemical components, which makes it important to study the cytotoxicity of PM2.5 in different seasons. Traditional immersion exposure cannot simulate the living environment of human epithelial cells in the human body, making this method unsuitable for evaluating the inhalation toxicity of PM2.5. In this study, a novel air-liquid interface (ALI) particulate matter exposure device (VITROCELL Cloud 12 system) was used to evaluate the toxic effects and potential mechanisms of human lung epithelial cells (A549) after exposure to seasonal PM2.5. PM2.5 samples from four seasons were collected and analyzed for chemical components. After 6 h of exposure to seasonal PM2.5, winter PM2.5 exhibited the highest cytotoxicity among most toxicity indicators, especially apoptosis rate, reactive oxygen species (ROS), inflammatory responses and DNA damage (γ-H2AX). The effect of autumn PM2.5 on apoptosis rate was significantly higher than that in spring, and there was no significant difference in other toxicity indicators between spring and autumn. The cytotoxicity of summer PM2.5 was the lowest among the four seasons. It should be noted that even exposure to low doses of summer PM2.5 leads to significant DNA damage in A459 cells. Correlation analysis results showed that water-soluble ions, metallic elements, and polycyclic aromatic hydrocarbons (PAHs) were associated with most toxicological endpoints. Inhibitors of oxidative stress and endoplasmic reticulum (ER) stress significantly inhibited cellular damage, indicating that PM2.5-induced cytotoxicity may be related to the generation of ROS and ER stress. In addition, PM2.5 can induce ER stress through oxidative stress, which ultimately leads to apoptosis.

Medium term moderate to low-level air pollution exposure is associated with higher C-reactive protein among healthy Danish blood donors

Air pollution is a significant contributor to the global burden of disease with a plethora of associated health effects such as pulmonary and systemic inflammation. C-reactive protein (CRP) is associated with a wide range of diseases and is associated with several exposures. Studies on the effect of air pollution exposure on CRP levels in low to moderate pollution settings have shown inconsistent results. In this cross-sectional study high sensitivity CRP measurements on 18,463 Danish blood donors were linked to modelled air pollution data for NOx, NO2, O3, CO, SO2, NH3, mineral dust, black carbon, organic carbon, sea salt, secondary inorganic aerosols and its components, primary PM2.5, secondary organic aerosols, total PM2.5, and total PM10 at their residential address over the previous month. Associations were analysed using ordered logistic regression with CRP quartile as individuals outcome and air pollution exposure as scaled deciles. Analyses were adjusted for health related and socioeconomic covariates using health questionnaires and Danish register data. Exposure to different air pollution components was generally associated with higher CRP (odds ratio estimates ranging from 1.11 to 1.67), while exposure to a few air pollution components was associated with lower CRP. For example, exposure to NO2 increased the odds of high CRP 1.32-fold (95%CI 1.16-1.49), while exposure to NH3 decreased the odds of high CRP 0.81-fold (95%CI 0.73-0.89). This large study among healthy individuals found air pollution exposure to be associated with increased levels of CRP even in a setting with low to moderate air pollution levels.

PM2.5 exposure at different concentrations and modes induces reproductive toxicity in male rats mediated by oxidative and endoplasmic reticulum stress

The molecular mechanisms of PM_2.5 exposure in the male reproductive system, have scarcely been studied. Here, we demonstrate the possible relationship and molecular mechanisms between endoplasmic reticulum stress (ERS), oxidative stress, and reproductive toxicity caused by PM_2.5. A "PM_2.5 real-time online concentrated animal whole-body exposure system" was employed to expose male Wistar rats to PM_2.5 for 12 weeks, which could induce sperm quality decline, apoptosis, inflammation, oxidative stress, ERS, and histopathological damage in the testis. In vitro study on cultured primary testicular spermatogonia and Leydig cells confirmed that treatment with PM_2.5 (0-320 μg/mL) for 24 h decreased cell survival rate, increased reactive oxygen species, lactate dehydrogenase and 8-hydroxydeoxyguanosine levels, induced DNA damage, ERS and apoptosis, and inhibit the secretion and synthesis of testosterone in Leydig cells. These results clarified that ERS pathways triggered by oxidative stress could significantly induce CHOP and caspase-12 activation, which are significantly associated with cell apoptosis. However, oxidative stress and ERS inhibitors significantly inhibited the occurrence of these injuries. In conclusion, PM_2.5 triggers the ERS pathway and induces DNA damage in rat testicular cells through oxidative stress, ultimately leading to cellular apoptosis. Furthermore, high-concentration intermittent inhalation was more harmful than low-concentration continuous inhalation when the total mass of PM_2.5 exposure was the same.

Particulate matter in COPD pathogenesis: an overview

Chronic obstructive pulmonary disease (COPD) is a progressive lung disorder with substantial patient burden and leading cause of death globally. Cigarette smoke remains to be the most recognised causative factor behind COPD pathogenesis. Given the alarming increase in prevalence of COPD amongst non-smokers in recent past, a potential role of air pollution particularly particulate matter (PM) in COPD development has gained much attention of the scientists. Indeed, several epidemiological studies indicate strong correlation between airborne PM and COPD incidence/exacerbations. PM-induced oxidative stress seems to be the major player in orchestrating COPD inflammatory cycle but the exact molecular mechanism(s) behind such a process are still poorly understood. This may be due to the complexity of multiple molecular pathways involved. Oxidative stress-linked mitochondrial dysfunction and autophagy have also gained importance and have been the focus of recent studies regarding COPD pathogenesis. Accordingly, the present review is aimed at understanding the key molecular players behind PM-mediated COPD pathogenesis through analysis of various experimental studies supported by epidemiological data to identify relevant preventive/therapeutic targets in the area.

Overweight improves long-term survival in Japanese patients with asthma

BACKGROUND

Obesity is a risk factor for severe and difficult-to-treat asthma. However, the impact of different physiques on long-term outcomes is poorly understood. We aimed to investigate the correlation between obesity and asthma-associated long-term mortality in Japanese adults.

METHODS

From the data on 3146 individuals with air pollution-related respiratory diseases in the Omuta City Air Pollution-Related Health Damage Cohort Program, 697 adult patients with asthma were analyzed. Hazard ratios for long-term all-cause and respiratory disease -related mortality were compared in patients with different physiques using the Cox proportional hazard models. The classification of physiques was based on the WHO obesity criteria.

RESULTS

Of the 697 patients, 439 died during the median observation period of 26.3 years. The number (% of total) of underweight, normal-weight, pre-obese, and obese class I-III individuals were 75 (10.8%), 459 (65.9%), 140 (20.1%), and 23 (3.3%), respectively. The Cox proportional hazard model (adjusted hazard ratio [95% confidence interval], P value) showed that pre-obese group had a significantly reduced risk for all-cause (0.65 [0.51 to 0.83], P < 0.05) and respiratory disease (0.55 [0.37 to 0.81], P < 0.05)-related mortality related to normal-weight group.

CONCLUSIONS

Our cohort program demonstrated that being slightly overweight may reduce the risk of long-term mortality in patients with asthma. However, the influence of obesity on long-term outcomes remains unclear in asthma, because of the small number of obese patients included in our study. Our findings suggest that interventions, including nutrition and exercises, should be provided to Japanese patients with asthma.

Impact of airflow obstruction on long-term mortality in patients with asthma in Japan

BACKGROUND

The long-term prognosis of asthma with airflow obstruction is poorly understood in Japan. The aim of this retrospective 26-year study was to investigate the long-term mortality risk of airflow obstruction in asthmatics.

METHODS

Using data from the Omuta City Air Pollution-related Health Damage Cohort Program, mortality risk ratios of airflow obstruction in Japanese Individuals were analyzed by Cox proportional hazards models. Airflow obstruction was considered to be present when the forced expiratory volume in 1 sec (FEV₁)/forced vital capacity ratio was <0.7 and FEV₁ predicted was <80% based on spirometry.

RESULTS

Among the 3146 victims with chronic respiratory diseases, 697 with adult asthma were selected. Median follow-up period was 26.3 (range 0.9-40.9) years. The airflow obstruction group (n = 193) showed significantly higher rates of mortality related to respiratory problems (risk ratio [95% confidence interval] 1.51 [1.86-1.93], P = 0.0017) and asthma attacks (1.86 [1.30-2.66], P = 0.0011) than the without airflow obstruction group (n = 504). Airflow obstruction was an independent risk factor for both respiratory-related (1.84 [1.36-2.49], P = 0.0001) and all-cause (1.44 [1.17-1.76], P = 0.0008) mortality after adjustment for age, sex, body mass index, and smoking status. More severe airflow obstruction was significantly associated with poorer prognosis.

CONCLUSIONS

This long-term cohort program revealed the impacts of asthma with airflow obstruction as an independent mortality risk. Findings suggest that intervention and prevention of airflow obstruction can reduce long-term mortality in patients with asthma.

Use of S1QELs and S3QELs to link mitochondrial sites of superoxide and hydrogen peroxide generation to physiological and pathological outcomes

Changes in mitochondrial superoxide and hydrogen peroxide production may contribute to various pathologies, and even aging, given that over time and in certain conditions, they damage macromolecules and disrupt normal redox signalling. Mitochondria-targeted antioxidants such as mitoQ, mitoVitE, and mitoTEMPO have opened up the study of the importance of altered mitochondrial matrix superoxide/hydrogen peroxide in disease. However, the use of such tools has caveats and they are unable to distinguish precise sites of production within the reactions of substrate oxidation and the electron transport chain. S1QELs are specific small-molecule Suppressors of site IQElectron Leak and S3QELs are specific small-molecule Suppressors of site IIIQoElectron Leak; they prevent superoxide/hydrogen production at specific sites without affecting electron transport or oxidative phosphorylation. We discuss the benefits of using S1QELs and S3QELs as opposed to mitochondria-targeted antioxidants, mitochondrial poisons, and genetic manipulation. We summarise pathologies in which site IQ in mitochondrial complex I and site IIIQo in mitochondrial complex III have been implicated using S1QELs and S3QELs.

Inflammatory health effects of indoor and outdoor particulate matter

Inflammation is a common and essential event in the pathogenesis of diverse diseases. Decades of research has converged on an understanding that all combustion-derived particulate matter (PM) is inflammatory to some extent in the lungs and also systemically, substantially explaining a significant portion of the massive cardiopulmonary disease burden associated with these exposures. In general, this means that efforts to do the following can all be beneficial: reduce particulates at the source, decrease the inflammatory potential of PM output, and, where PM inhalation is unavoidable, administer anti-inflammatory treatment. A range of research, including basic illumination of inflammatory pathways, assessment of disease burden in large cohorts, tailored treatment trials, and epidemiologic, animal, and in vitro studies, is highlighted in this review. However, meaningful translation of this research to decrease the burden of disease and deliver a clear and cohesive message to guide daily clinical practice remains rudimentary. Ongoing efforts to better understand substantial differences in the concentration and type of PM to which the global community is exposed and then distill how that influences inflammation promises to have real-world benefit. This review addresses this complex topic in 3 sections, including ambient PM (typically associated with ground-level transportation), wildfire-induced PM, and PM from indoor biomass burning. Recognizing the overlap between these domains, we also describe differences and suggest future directions to better inform clinical practice and public health.

Effectiveness of diagnostic screening tests in mass screening for COPD using a cooperative regional system in a region with heavy air pollution: a cross-sectional study

OBJECTIVES

This study aimed to evaluate the effectiveness of a cooperative healthcare model for early detection and diagnosis of chronic obstructive pulmonary disease (COPD).

METHODS

This was a cross-sectional observational study. We performed diagnosis of COPD at 4 public health centres in Ōmuta, Japan from March 2015 to March 2016, by adding screening for COPD at the time of routine medical evaluations. All patients aged over 40 years were eligible to participate. Among 397 eligible patients, 293 agreed to participate in the study.

RESULTS

The estimated prevalence of COPD in Ōmuta was 10% among patients aged over 40 years and was 17% among smokers. Among those who were screened, over half of them had questionnaire scores over the cut-off of 17 points and decreased FEV1/FVC%, indicating COPD (p>0.05). 30 patients with suspected COPD were referred for further investigation at a local central hospital, but only 6 underwent further medical examinations.

CONCLUSIONS

The combination of a COPD questionnaire and medical examination is effective as a COPD screening tool. Future research should investigate behavioural interventions for smoking cessation that can be offered in a cooperative model, as well as for improving participation in COPD screening and for encouraging early presentation for treatment in those suspected of having COPD.

Factors associated with the annual change in forced expiratory volume in 1 second of officially acknowledged victims of pollution-related illness in improved environments: a longitudinal study

[Purpose] We examined factors affecting annual change in pulmonary function in residents previously exposed to air pollution in an area where pollution has been reduced and a long time period has elapsed. [Subjects and Methods] Data of 730 officially acknowledged victims of pollution-related illness from an annual survey during 2000 to 2009 were analyzed. The primary outcome was forced expiratory volume in 1 second (FEV₁), along with factors such as age, body composition, smoking habits, respiratory symptoms, and classification of medical management (an index of the need for treatment). Multiple regression analyses were used to identify factors associated with the annual change in FEV₁. [Results] Three significant factors were identified: smoking habit, classification of medical management, and gender. Smoking habits and classification of medical management had stronger effects on the annual change in FEV₁ than gender. [Conclusion] With an improved environment, continuation of smoking accelerates the decline in FEV₁.

Smoking aggravates the impaired pulmonary function of officially acknowledged female victims of air pollution of 40 years ago

Air pollution due to industrial waste and tobacco smoke is detrimental to pulmonary function. However, the combined effects of air pollution and smoking on pulmonary function have not been investigated. We examined the combined effect of air pollution of 40 years ago and concurrent smoking on the pulmonary function of officially acknowledged female victims in Japan, because females are more susceptible to the adverse effects of both irritants than males. The subjects comprised 655 female victims living in one of two areas with air pollution of 40 years ago and 572 females living in an area without air pollution. All victims have been prescribed standard respiratory medications. Pulmonary function was measured in 2000 for air-pollution groups (130 smokers and 525 non-smokers; mean age, 68.4 years) and during the period of 2004 to 2013 for non-air-pollution groups (113 smokers and 459 non-smokers; mean age, 69.0 years). The smokers included both current smokers and ex-smokers. The victims with a history of smoking had significantly lower forced expiratory volume in 1 second (FEV1 % predicted) (mean, 74%) and significantly lower FEV1/forced vital capacity (FVC) (mean, 70%) than the other groups (P<0.001). Thus, smoking aggravates the pulmonary function in officially acknowledged female victims, despite the improved air pollution and the continuous medical care provided by the government. In conclusion, exposure to air pollution of 40 years ago and cigarette smoking are associated with reduced pulmonary function. These results highlight the importance of measures aimed at smoking cessation and limiting air pollution.

Adverse effects of outdoor pollution in the elderly

With fewer newborns and people living longer, older people are making up an increasing fraction of the total population. Epidemiological evidence shows that older-age-related health problems affect a wide and expanding proportion of the world population. One of the major epidemiological trends of this century is the rise of chronic diseases that affect more elderly than younger people. A total of 3.7 million premature deaths worldwide in 2012 are attributable to outdoor air pollution; the susceptibility to adverse effects of air pollution is expected to differ widely between people and within the same person, and also over time. Frailty history, a measure of multi-system decline, modifies cumulative associations between air pollution and lung function. Moreover, pre-existing diseases may determine susceptibility. In the elderly, due to comorbidity, exposure to air pollutants may even be fatal. Rapid and not-well-planned urbanization is associated with high level of ambient air pollution, mainly caused by vehicular exhausts. In general, there is sufficient evidence of the adverse effects related to short-term exposure, while fewer studies have addressed the longer-term health effects. Increased pollution exposures have been associated with increased mortality, hospital admissions/emergency-room visits, mainly due to exacerbations of chronic diseases or to respiratory tract infections (e.g., pneumonia). These effects may also be modulated by ambient temperature and many studies show that the elderly are mostly vulnerable to heat waves. The association between heat and mortality in the elderly is well-documented, while less is known regarding the associations with hospital admissions. Chronic exposure to elevated levels of air pollution has been related to the incidence of chronic obstructive pulmonary disease (COPD), chronic bronchitis (CB), asthma, and emphysema. There is also growing evidence suggesting adverse effects on lung function related to long-term exposure to ambient air pollution. Few studies have assessed long-term mortality in the elderly. It is still unclear what are the pollutants most damaging to the health of the elderly. It seems that elderly subjects are more vulnerable to particulate matter (PM) than to other pollutants, with particular effect on daily cardio-respiratory mortality and acute hospital admissions. Not many studies have targeted elderly people specifically, as well as specific respiratory morbidity. Most data have shown higher risks in the elderly compared to the rest of the population. Future epidemiological cohort studies need to keep investigating the health effects of air pollutants (mainly cardiopulmonary diseases) on the elderly.

Physical Function Traits of Long-term Officially Acknowledged Victims of Pollution-related Illnesses Compared with Elderly Patients with Chronic Obstructive Pulmonary Disease

[Purpose] To examine the long-term effects of air pollution on the physical functioning of a group of officially acknowledged victims of pollution-related illnesses (Victims group) who were exposed to air pollution more than 50 years ago, we compared them with age-matched patients with chronic obstructive pulmonary disease (COPD group). [Subjects and Methods] The Victims group comprised 34 subjects and the COPD group 24, all of whom were aged over 65 years. Respiratory function, muscle strength, exercise capacity and physical activity were measured and compared between the groups. [Results] The Victims group had significantly higher forced expiratory volume in the first second (FEV1), proportion of predicted FEV1, proportion of predicted vital capacity (VC), and ratio of FEV1 to forced VC than the COPD group. Surprisingly, the muscle strength of the Victims group was significantly weaker, their incremental shuttle walking test distance was significantly shorter, and their physical activity was significantly less than those of the COPD group. [Conclusion] Although the pulmonary function of Victims was better than that of the COPD group, their physical functioning was worse. Exposure to air pollution 50 years ago appears to continue to adversely affect their physical function. It is particularly important to offer Victims rehabilitation to improve their exercise performance and physical activity.

Tobacco use among designated air pollution victims and its association with lung function and respiratory symptoms: a retrospective cross-sectional study

OBJECTIVES

We sought to elucidate the long-term association of tobacco use and respiratory health in designated pollution victims with and without obstructive pulmonary defects.

DESIGN

A retrospective cross-sectional study.

SETTING

The register of pollution victims in Kurashiki, Japan.

PARTICIPANTS

730 individuals over 65 years of age previously diagnosed with pollution-related respiratory disease. Patients were classified into four groups according to their smoking status and whether they had obstructive pulmonary disease. We then compared the prevalence of respiratory symptoms and lung function over time between groups.

PRIMARY OUTCOME MEASURES

Spirometry was performed and a respiratory health questionnaire completed in the same season each year for up to 30 years.

RESULTS

Rates of smoking and respiratory disease were high in our sample. Although respiratory function in non-smoking patients did not completely recover, the annual rate of change in lung function was within the normal range (p<0.01). However, smokers had worse lung function and were more likely to report more severe pulmonary symptoms (p<0.01).

CONCLUSIONS

Patients' respiratory function did not fully recover despite improved air quality. Our results suggest that, in the context of exposure to air pollution, tobacco use causes additional loss of lung function and exacerbates respiratory symptoms.

Prevalence of chronic sputum and associated factors in Korean adults

Chronic sputum is a troublesome symptom in many respiratory diseases. The prevalence of chronic sputum varies from 1.2% to 13% according to the country. The purpose of this study was to estimate the prevalence of chronic sputum and to find its associated factors in a general Korean population. We analyzed the data of the Korea National Health and Nutrition Examination Survey 2010 and 2011. A total number of 6,783 subjects aged 40 yr or more were enrolled in this study with 3,002 men and 3,781 women. As a result, the prevalence of chronic sputum was 6.3% (n=430). Significant risk factors for chronic sputum by multivariate analysis were: age (≥ 70 yr) (odds ratio [OR], 1.954; 95% confidence interval [CI], 1.308-2.917), current smoking (OR, 4.496; 95% CI, 3.001-6.734), chronic obstructive pulmonary disease (COPD) (OR, 1.483; 95% CI, 1.090-2.018), and tuberculosis (OR, 1.959; 95% CI, 1.307-2.938). In conclusion, the prevalence of chronic sputum in Korea was in the intermediate range compared with other countries. Smoking is a preventable risk factor identified in this study, and major respiratory diseases, such as COPD and tuberculosis, should be considered in subjects with chronic sputum.