COPD in Biomass exposed nonsmokers: a different phenotype

Biomass-related PM2.5 induced inflammatory microenvironment via IL-17F/IL-17RC axis

Biomass exposure is a significant environmental risk factor for COPD, but the underlying mechanisms have not yet been fully elucidated. Inflammatory microenvironment has been shown to drive the development of many chronic diseases. Pollution exposure can cause increased levels of inflammatory factors in the lungs, leading to an inflammatory microenvironment which is prevalent in COPD. Our findings revealed that IL-17F was elevated in COPD, while exposure to biomass led to increased expression of IL-17F in both alveolar epithelial and macrophage cells in mice. Blocking IL-17F could alleviate the lung inflammation induced by seven days of biomass exposure in mice. We employed a transwell co-culture system to simulate the microenvironment and investigate the interactions between MLE-12 and MH-S cells. We demonstrated that anti-IL-17F antibody attenuated the inflammatory responses induced by BRPM2.5 in MLE-12 and MH-S co-cultured with BRPM2.5-MLE-12, which reduced inflammatory changes in microenvironment. We found that IL-17RC, an important receptor for IL-17F, played a key role in the interactions. Knockout of IL-17RC in MH-S resulted in inhibited IL-17F signaling and attenuated inflammatory response after MH-S co-culture with BRPM2.5-MLE-12. Our investigation suggests that BRPM2.5 induces lung epithelial-macrophage interactions via IL-17F/IL-17RC axis regulating the inflammatory response. These results may provide a novel strategy for effective prevention and treatment of biomass-related COPD.

Role of prostanoids, nitric oxide and endothelin pathways in pulmonary hypertension due to COPD

Pulmonary hypertension (PH) due to chronic obstructive pulmonary disease (COPD) is classified as Group 3 PH, with no current proven targeted therapies. Studies suggest that cigarette smoke, the most risk factor for COPD can cause vascular remodelling and eventually PH as a result of dysfunction and proliferation of pulmonary artery smooth muscle cells (PASMCs) and pulmonary artery endothelial cells (PAECs). In addition, hypoxia is a known driver of pulmonary vascular remodelling in COPD, and it is also thought that the presence of hypoxia in patients with COPD may further exaggerate cigarette smoke-induced vascular remodelling; however, the underlying cause is not fully understood. Three main pathways (prostanoids, nitric oxide and endothelin) are currently used as a therapeutic target for the treatment of patients with different groups of PH. However, drugs targeting these three pathways are not approved for patients with COPD-associated PH due to lack of evidence. Thus, this review aims to shed light on the role of impaired prostanoids, nitric oxide and endothelin pathways in cigarette smoke- and hypoxia-induced pulmonary vascular remodelling and also discusses the potential of using these pathways as therapeutic target for patients with PH secondary to COPD.

Association of Exposure to Biomass Fuels with Occurrence of Chronic Obstructive Pulmonary Disease in Rural Western China: A Real-World Nested Case-Control Study

Background

This study investigated the potential contribution of biomass fuels exposure to the occurrence of chronic obstructive pulmonary disease (COPD) in rural areas of western China.

Methods

We analyzed data collected between October 2017 and October 2018 from a nested case-control study of individuals at least 40 years old in the general population in Mianyang City, Sichuan Province, China. Demographic information was collected using a custom-designed questionnaire, and lung function was measured using spirometry. We used multivariate logistic regression to explore the possible relationship between biomass fuels exposure and COPD, as well as between other potential risk factors and COPD. Bayes' theorem was used to estimate weights for different COPD risk factors.

Results

COPD was newly diagnosed in 500 of the 11398 adults surveyed, corresponding to an incidence of 4.39%. Individuals who were exposed to biomass fuels were at a significantly greater risk of developing COPD than those not exposed (OR 2.58, 95% CI 2.23-3.05). In subgroup analysis, exposure to biomass fuels increased the risk of COPD in men by 1.71 times (95% CI 1.09-2.68) and in women by 2.88 times (95% CI 2.01-3.48), in never-smokers by 2.18 times. Bayesian weights for COPD risk factors were highest for poor kitchen ventilation (W=31.13%) and biomass fuels exposure (W=18.08%).

Conclusion

Our data indicate that rural Chinese who are exposed to biomass fuels during cooking or heating are at greater risk of developing COPD. Efforts should be made to strengthen the construction of clean energy infrastructure, so as to reduce the use of biomass fuels and thereby help prevent COPD.

A2M Serves as Promising Biomarker for Chronic Obstructive Pulmonary Disease

Background

Chronic obstructive pulmonary disease (COPD) often associated with cigarette smoking. However, increasing evidence suggests that non-smoking COPD is much higher than previously thought. This study aims to identify a nonsmoking COPD biomarker and examined its value in diagnosis and prediction of acute exacerbation.

Methods

A total of 35 stable COPD patients, 70 acute exacerbation chronic obstructive pulmonary disease (AECOPD) patients and 35 healthy control subjects were included. Plasma α 2 macroglobulin (A2M) and matrix metalloproteinase-9 (MMP-9) levels were measured using the enzyme-linked immunosorbent assay (ELISA) method on all participants. Their association with clinical characteristics and lung function parameters were determined by regression analysis. Receiver operating characteristic (ROC) curve was used to determine the diagnostic sensitivity and specificity. Correlation coefficients were evaluated using Pearson's correlation.

Results

Plasma A2M concentration was decreased and MMP-9 concentration, MMP-9/A2M ratio were elevated in stable COPD patients compared with control groups. And MMP-9 expression was significantly higher in AECOPD patients. A2M level was increased in AECOPD patients with infection compared with those without. In addition, there was no statistical difference in A2M levels between smokers and nonsmokers COPD or healthy control subjects. Furthermore, A2M, MMP-9 and MMP-9/A2M were correlated with forced expiratory volume in one second (FEV₁)%, FEV₁/ forced vital capacity (FVC), CAT and mMRC score in COPD patients, but had no correlation with fraction of exhaled nitric oxide (FeNO) and concentration of alveolar nitric oxide (CaNO).

Conclusion

A2M is altered in peripheral blood of COPD patients and correlated with severity and infection. Moreover, there was no significant correlation between the change in A2M and smoking, FeNO and CaNO, suggesting A2M may reflect the overall rather than local inflammation in COPD patients and serve as a potential biomarker for nonsmoking COPD patients.

Overview of herbal therapy of acute and chronic pulmonary disease: a conceptual map

Purpose

Acute and chronic obstructive pulmonary disease (COPD) is a common and progressive lung disease that makes breathing difficult over time and can even lead to death. Despite this, there is no definitive treatment for it yet. This study aims to evaluate the studies on single and combined herbal interventions affecting COPD.

Design/methodology/approach

In this study, all articles published in English up to 2020 were extracted from the Web of Science (WoS) database and collected using Boolean tools based on keywords, titles and abstracts. Finally, the data required for bibliographic analysis, such as the author(s), publication year, academic journal, institution, country of origin, institution, financial institution and keywords were extracted from the database.

Findings

A total of 573 articles were analyzed. The number of papers in the lung disease field showed an upward trend from 1984 to 2021, and there was a surge in paper publications in 2013. China, Korea and Brazil published the highest number of studies on COPD, and Chinese medical universities published the most papers. Three journals that received the highest scores in this study were the Journal of Ethnopharmacology, International Immunopharmacology and Plos One. In the cloud map, expression, activation and expression were the most frequently researched subjects. In the plus and author keywords, acute lung injury was the most commonly used word. Inflammation, expression of various genes, nitric oxide-dependent pathways, NFkappa B, TNFalpha and lipopolysaccharide-dependent pathways were the mechanisms underlying COPD. Scientometric analysis of COPD provides a vision for future research and policymaking.

Originality/value

This study aimed to evaluate the studies on single and combined herbal interventions affecting COPD.

Small airway dysfunction in pneumoconiosis: a cross-sectional study

Background

Although several histological studies have documented airway inflammation and remodelling in the small airways of dust-exposed workers, little is known regarding the prevalence and risk factors of small airway dysfunction (SAD) in pneumoconiosis. The present study investigated the prevalence and characteristics of spirometry-defined SAD in pneumoconiosis and assessed the risk factors for associated with SAD.

Methods

A total of 1255 patients with pneumoconiosis were invited to participate, of whom 1115 patients were eligible for final analysis. Spirometry was performed to assess SAD using the following three indicators: maximal mid-expiratory flow and forced expiratory flow 50% and 75%. SAD was defined as at least two of these three indicators being less than 65% of predicted value. Logistic regression analyses were used to analyse the relationships between clinical variables and SAD.

Results

Overall, 66.3% of patients with pneumoconiosis had SAD, among never-smokers the prevalence of SAD was 66.7%. The proportion of SAD did not differ among the subtypes of pneumoconiosis. In addition, SAD was present across the patients with all stages of pneumoconiosis. Even among those with forced expiratory volume in 1 s (FEV₁) ≥ 80% and FEV₁/forced vital capacity ratio ≥ 70%, 40.8% of patients had SAD. Patients with SAD were older than patients without SAD, more likely to be women and heavy smokers. Importantly, patients with SAD had more severe airflow obstruction, air trapping, and diffusion dysfunction. All patients with both pneumoconiosis and chronic obstructive pulmonary disease had SAD. Based on multivariate analysis, overall, aged 40 years and older, female sex, heavy smoking, body mass index ≥ 25.0 kg/m² and pneumoconiosis stage III were significantly associated with increased risk of SAD. Among the never smokers, risk factors for SAD included female sex, BMI ≥ 25.0 kg/m², pneumoconiosis stage II and stage III

Conclusion

Spirometry-defined SAD is one of the common functional abnormalities caused by occupational dust exposure and should be taken into account when monitoring respiratory health of workers to guide the early precautions and management in pneumoconiosis.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12890-022-01929-9.

Is pulmonary tuberculosis a true risk-factor for chronic obstructive pulmonary disease?

This viewpoint discusses the possible relationship of tuberculosis with chronic obstructive pulmonary disease. Pulmonary tuberculosis as a risk factor and/or complication of COPD is reported in several reports from African and Asian countries. History of TB seems to have an important role in the natural history of COPD. It is difficult to conclude whether this is a true causal relationship or merely an incidental observation due to the concurrent presence of the two commonly prevalent diseases and their risk factors. Many of these disease and treatment-related factors can promote and/or aggravate disease condition.

Strategies for the prevention, diagnosis and treatment of COPD in low- and middle- income countries: the importance of primary care

INTRODUCTION

Low- and middle-income countries (LMICs) bear a high proportion of the global morbidity and mortality caused by COPD. Increased exposure to risk factors throughout life (e.g. malnutrition, indoor and outdoor air pollution, and smoking) is associated with higher COPD prevalence in LMICs and the lack of treatment availability increases avoidable harm.

AREAS COVERED

This review covers the epidemiology and burden of COPD in LMICs, and challenges and recommendations related to health-care systems, prevention, diagnosis, and treatment. Main challenges are related to under-resourced health-care systems (such as limited availability of spirometry, rehabilitation, and medicines). Lack of policy and practical local guidelines on COPD diagnosis and management further contribute to the low diagnostic and treatment rates. In the absence of, or limited number of respiratory specialists, primary care practitioners (general practitioners, nurses, pharmacists, physiotherapists, and community health workers) play an even more pivotal role in COPD management in LMICs.

EXPERT OPINION

Raising awareness on COPD, educating health-care workers, patients, and communities on cost-effective preventive measures as well as improving availability, affordability and proper use of diagnostic and pharmacological and non-pharmacologic treatment in primary care are the key interventions needed to improve COPD prevention, diagnosis, and care in LMICs.

The "Slow Horse Racing Effect" on Lung Function in Adult Life in Chronic Obstructive Pulmonary Disease Associated to Biomass Exposure

Although different trajectories in lung function decline have been identified in patients with COPD associated to tobacco exposure (TE-COPD), genetic, environmental, and infectious factors affecting lung function throughout life have not been fully elucidated in patients with COPD associated to biomass (BE-COPD). In this review, we present current epidemiological findings and notable advances in the natural history of lung decline in BE-COPD, as well as conditions modeling the FEV₁ trajectory, such as health insults, during the first years of childhood. Evidence shows that women exposed to biomass smoke reach adult life with a lower FEV₁ than expected. However, in contrast to the “horse racing effect” predicting an excessive lung-function decline in forthcoming years, as observed in smokers, this decline is slower in non-smokers, and no rapid decliners are observed. Accordingly, BE-COPD might be considered another phenotype of COPD based on assessments of lung function decline. Likewise, other functional and clinical aspects described in this review suggest that this condition might be similar to TE-COPD. More research is needed to fully characterize this subgroup of variants of COPD.

Exposure to biomass smoke induces pulmonary Th17 cell differentiation by activating TLR2 on dendritic cells in a COPD rat model

Almost three billion people in developing countries are exposed to biomass smoke (BS), which predisposes them to developing chronic obstructive pulmonary disease (COPD). COPD is associated with abnormal innate and adaptive immune responses in the lungs and systemic circulation, but the mechanisms underlying BS-COPD development are uncertain. We investigated the role of dendritic cells (DCs) and interleukin (IL)-17A in BS-COPD. We investigated T helper cell responses in the BS-exposed COPD rat model by flow cytometry, quantitative PCR, and enzyme-linked immunosorbent assays. We conducted ex vivo experiments to determine which antigen-presenting cells induce Th17 cell responses. We evaluated the in vitro effects of BS-related particulate matter (BRPM) (2.5 μm) on the function of bone marrow-derived dendritic cells (BMDCs). We found that BS exposure enhanced Th17 responses in the lungs of the COPD-modelled rats, and the stimulated DCs (but not the macrophages) were sufficient to induce naïve CD4 + T cells to produce IL-17A in ex vivo experiments. BRPM significantly enhanced the maturation and activation of DCs through Toll-like receptor 2 (TLR2), but not TLR4, and induced Th17 responses. Therefore, BS activated lung DCs through TLR2, which led to Th17 responses and emphysema in the rats. This process is possibly therapeutically targetable.