Particulate matter in COPD pathogenesis: an overview

COPD risk due to extreme temperature exposure: combining epidemiological evidence with pathophysiological mechanisms

Climate change is amplifying the frequency and intensity of extreme temperature events, posing a significant risk for chronic obstructive pulmonary disease (COPD). This review synthesised epidemiological evidence linking extreme temperature to COPD morbidity and mortality, while elucidating synergistic interactions with other environmental exposures. Combining population-level findings with biomedical mechanistic insights, we proposed a framework illustrating how biomarkers bridge the gap between extreme temperature exposure and COPD, highlighting the pathophysiological mechanisms of prodromal symptoms, key pathogenic processes and early molecular events. The mechanisms and biomarkers identified in this study would provide critical information for elucidating the causal pathways through which extreme temperatures increase COPD risk, and thus inform preventive interventions. Future research should incorporate multi-omics techniques to explore the underlying mechanisms in greater depth, while validating the biomarkers through large-scale cohort studies.

A Peptide Encoded by lncRNA HOXB-AS3 Promotes Cigarette Smoke-Induced Inflammation in Bronchial Epithelial Cells via EZH2-Mediated H3K27me3 Modification

Background

Chronic obstructive pulmonary disease (COPD) primarily results from cigarette smoke (CS)-induced chronic inflammation. Although numerous long non-coding ribonucleic acids (lncRNAs) have been extensively studied for their crucial roles in COPD, the peptides encoded by these lncRNAs have garnered limited attention. This study aimed to investigate the role of a peptide encoded by lncRNA HOXB-AS3 in cigarette smoke extract (CSE)-induced inflammation and in 16HBE cells.

Methods

Open reading frames (ORF) Find software was utilized to predict the encoding potential of HOXB-AS3. Quantitative real-time polymerase chain reaction (qRT-PCR) was employed to detect the levels of peptide HOXB-AS3-32aa in peripheral blood mononuclear cells (PBMCs) from both healthy controls and COPD patients and in 16HBE cells exposed to different CSE. To establish an in vitro inflammatory cell model of COPD, 16HBE cells were treated with 2% CSE. Enzyme-Linked Immunosorbent Assay (ELISA) measured inflammatory cytokines, while CCK-8 assay assessed cell viability. Flow cytometry was employed to assess cell apoptosis. Western blot analysis was performed to measure the expression of HOXB-AS3-32aa, EZH2, and H3K27me3 proteins. Co-Immunoprecipitation (Co-IP) was conducted to verify the interaction between EZH2 and HOXB-AS3-32aa.

Results

Our findings revealed elevated expression of HOXB-AS3-32aa in PBMCs of COPD patients compared to controls. CSE treatment dose-dependently increased HOXB-AS3-32aa expression. Overexpression of HOXB-AS3-32aa exacerbated CS-induced inflammation in bronchial epithelial cells, leading to inhibited cell proliferation and increased cell apoptosis. Furthermore, HOXB-AS3-32aa suppressed EZH2 and H3k27me3 protein levels in 16HBE cells. Co-IP results confirmed the interaction between HOXB-AS3-32aa and EZH2 protein.

Conclusion

Our results demonstrate that the novel peptide HOXB-AS3-32aa encoded by lncRNA HOXB-AS3 promotes CS-induced inflammation and apoptosis in 16HBE cells via EZH2-mediated H3K27me3 modification.

Identification and verification of mitochondria-related genes biomarkers associated with immune infiltration for COPD using WGCNA and machine learning algorithms

Mitochondrial dysfunction plays a pivotal role in the pathogenesis of chronic obstructive pulmonary disease (COPD). This study combines bioinformatics analysis with machine learning to elucidate potential key mitochondrial-related genes associated with COPD and its immune microenvironment. We utilized the limma package and Weighted Gene Co-expression Network Analysis (WGCNA) to analyze datasets from the Gene Expression Omnibus (GEO) database (GSE57148), identifying 12 key differentially expressed mitochondrial genes (MitoDEGs). Using 12 distinct machine learning algorithms (comprising 143 predictive models), we identified the optimal diagnostic model, which includes five pivotal MitoDEGs: ERN1, FASTK, HIGD1B, NDUFA7 and NDUFB7. The diagnostic specificity and sensitivity of each gene, as well as the diagnostic model itself, were evaluated using Receiver operating characteristic (ROC) curves. This model demonstrated high specificity in the validation cohorts (GSE76925, GSE151052, GSE239897). Expression analysis revealed upregulation of ERN1 and downregulation of FASTK, HIGD1B, NDUFA7 and NDUFB7 in COPD patients. Spearman's correlation analysis indicated a significant association between MitoDEGs and immune cell infiltration, with ERN1 expression positively correlated with neutrophil infiltration and the other genes negatively correlated. The GABA receptor modulator androstenol was identified as a potential therapeutic candidate. In vivo studies confirmed reduced mRNA expression of HIGD1B and NDUFB7 in COPD mice. These findings elucidate mitochondrial-immune interactions in COPD and highlight novel diagnostic and therapeutic targets.

N‑acetyl‑L‑cysteine protects rat lungs and RLE‑6TN cells from cigarette smoke‑induced oxidative stress

Cigarette smoke (CS) is a key contributor of chronic obstructive pulmonary disease (COPD); however, its role in the pathogenesis of COPD has not been fully elucidated. N‑acetyl‑L‑cysteine (NAC), as an antioxidant, has been used in the treatment of COPD; however, the mechanisms of action of NAC are not fully understood. Alveolar epithelial type 2 (ATII) cells serve an essential role in the maintenance of alveolar integrity. The aim of the present study was to identify the effect of CS on rat lungs and ATII cells. A subacute lung injury model of Wistar rats was established using CS exposure for 4 weeks. Interalveolar septa widening, infiltration of inflammatory cells, edema fluid in airspaces and abnormal enlargement of airspaces were observed through H&E staining. ELISA revealed that NAC could protect against CS‑induced increases in serum levels of malondialdehyde and decreases in serum levels of superoxide dismutase. Additionally, 8‑hydroxy‑deoxyguanosine was detected using immunohistochemical staining, and this was also expressed at increased levels in the lung tissue of the CS‑exposed group. In addition, the expression levels of Bcl‑2, BAX and caspase‑3 p12 in lung tissue were detected by western blotting or immunohistochemical staining. The expression levels of Bcl‑2 decreased and those of caspase3 p12 were increased in response to CS exposure when compared with those in the control group. These effects were prevented by treatment with NAC. In vitro, the effect of CS extract (CSE) on rat lung epithelial‑6‑T‑antigen negative (RLE‑6TN) cells was observed, flow cytometry was used to detect intracellular reactive oxygen species (ROS) levels and the occurrence of apoptosis, and the content of glutathione (GSH) was detected using a colorimetric assay. Additionally, the expression levels of heme oxygenase‑1 (HO‑1), p53 and Bcl‑2 were examined by western blotting, and HO‑1 mRNA expression was also examined using reverse transcription‑quantitative PCR. The results of the present study revealed that CSE induced apoptosis of RLE‑6TN cells, accompanied by increased levels of intracellular ROS and exhaustion of GSH. Significantly increased protein levels of HO‑1 and p53, as well as decreased protein levels of Bcl‑2 were also observed. These effects were prevented by administration of NAC. Overall, these findings suggested that CS could promote apoptosis in rat lung tissues and alveolar epithelial cells by inducing intracellular oxidative injury, and NAC may serve an antioxidant role by replenishing the intracellular GSH content.

Assessment of air pollutant O3 pulmonary exposure using a bronchus-on-chip model coupling with atmospheric simulation chamber

Heavy air pollution is now a serious public health issue. Many studies have shown strong connections between ozone (O3) with the occurrence and development of various respiratory diseases. However, the exact mechanism is still a matter of debate. In this work, we developed a human bronchial epithelial cells (HBECs) chip that differentiates different functional cell groups of ciliated, goblet, and club cells to model the pulmonary bronchial barrier function. Concurrently, we designed an Atmospheric-Biochemical-Chip reactor (ABC-reactor), a system that could simulate different levels of O3 and particle matter. Coupling the HBECs-on-chip model with ABC-reactor, we investigated the effects of O3 at 400 ppbv and 200 ppbv on the pulmonary bronchial barrier. Our results showed that O3 at 400 ppbv severely disrupted the bronchial barrier and upregulated the expression of pro-inflammatory cytokines. However, 200 ppbv of O3 did not cause severe barrier impairment but induced cellular dysfunction, apoptosis, and reduced immune response. These suggest that bronchial trauma does exist at 200 ppbv of O3 but is not easily detected by the body due to the reduced inflammatory response. However, more research is needed to understand if the trauma induced by 200 ppbv of O3 is reversible and the interaction mechanism between O3 and PM2.5.

Relationship between systemic immune response index (SIRI) and COPD: a cross-sectional study based on NHANES 2007-2012

Although the link between inflammation and chronic obstructive pulmonary disease (COPD) is increasingly recognized, the correlation between systemic immune response index (SIRI), a novel marker of inflammation, and COPD is unknown. This cross-sectional study used data from patients with complete lung function in NHANES 2007-2012 to explore the relationship between SIRI and COPD. We performed a series of statistical analyses on a total of 5056 participants, including multiple linear regression, smoothed curve fitting, ROC curve analysis, and subgroup analysis. In the fully corrected model, the logistic multiple regression showed that SIRI was associated with a high risk of COPD (OR1.350, 95% CI:1.220,1.493). The ROC curve showed that SIRI (AUC = 0.596) was significantly more efficient than other inflammatory factors in predicting COPD. Smoothed curve fit effect and threshold effect analyses showed a linear correlation between SIRI COPD prevalence, and subgroup analyses showed that the effect of SIRI on COPD was more pronounced in still smokers (OR 1.58, 95% CI: 1.34, 1.86) versus men (OR 1.62, 95% CI: 1.44, 1.83). The results of the interaction test provide evidence supporting SIRI as an independent risk factor for COPD.

Prognostic value of composite inflammatory markers in patients with chronic obstructive pulmonary disease: A retrospective cohort study based on the MIMIC-IV database

Chronic obstructive pulmonary disease (COPD) is a chronic inflammatory lung disease, and inflammation plays a key role in the pathogenesis of COPD. The aim of this study is to investigate the association between systemic immune inflammation index (SII), systemic inflammatory response index (SIRI),pan-immune inflammation value (PIV), neutrophil-to-lymphocyte ratio (NLR), and platelet-to-lymphocyte ratio (PLR) and all-cause mortality in patients with chronic obstructive pulmonary disease (COPD), and to evaluate the effect of composite inflammatory markers on the prognosis of COPD patients. We obtained data on COPD patients from the Medical Information Mart for Intensive Care (MIMIC) -IV database and divided patients into four groups based on quartiles of baseline levels of inflammatory markers, The primary outcomes were in-hospital and ICU mortality. We comprehensively explored the association between composite inflammatory markers and mortality in patients with COPD using restricted cubic splints (RCS), COX proportional hazards regression models, Kaplan-Meier curves, receiver operating characteristic (ROC), and subgroup analyses. A total of 1234 COPD patients were included in this study. RCS results showed that SII, SIRI, PLR, PIV and NLR were positively and non-linearly correlated with the increased risk of in-hospital mortality in COPD patients. Multivariate COX regression analysis showed that compound inflammatory markers were independent risk factors for in-hospital mortality in COPD patients. The KM curve results showed that COPD patients with higher SII, SIRI, PLR and PIV had a significantly lower survival probability. 5 kinds of compound between inflammatory markers and mortality in patients with COPD is related to nonlinear correlation, can increase the risk of mortality in patients with COPD is a risk factor for the prognosis of patients with COPD, and may serve as potential biomarkers for clinical COPD risk stratification and treatment management in critical patients.

SLC27A3 downregulation restores Th17/Treg balance and alleviates COPD via JAK2/STAT3 pathway inhibition

The main goal of this investigation is to find out how solute carrier family 27 member 3 (SLC27A3) is expressed in the lung tissue of mice with chronic obstructive pulmonary disease (COPD), and how it relates to lung function. A model of COPD was established by exposing organisms to cigarette smoke, followed by investigating the role of SLC27A3 in COPD through experiments conducted both in living organisms and in laboratory settings. Knockout mice lacking SLC27A3 were produced through siRNA transfection to investigate lung function and inflammatory response, using methods such as hematoxylin-eosin staining and enzyme-linked immunosorbent assay. Western blotting was carried out to analyze the expression of SLC27A3. Naïve CD4+ T-cells were stimulated with anti-CD3, anti-CD28, transforming growth factor (TGF)-β, and/or interleukin (IL)-6, and their differentiation into Th17 or Treg cells was promoted, as assessed by flow cytometry. The pathway expression of JAK2/STAT3 was detected using Western blotting. Mice with COPD that had higher expression levels of SLC27A3 in their lung tissue display abnormalities in lung architecture and function, as well as an imbalance between Th17 and Tregs and an elevated inflammatory response. In COPD mice with SLC27A3 knockdown, the JAK2/STAT3 pathway was repressed, lung inflammation was decreased, Th17/Treg balance was improved, and lung functioning was improved. In conclusion, the findings of this study suggest that downregulating SLC27A3 has the potential to attenuate the inflammatory response, mitigate COPD progression, and rebalance the Th17/Treg ratio by inhibiting the JAK2/STAT3 signaling pathway. These results lay a foundation for utilizing SLC27A3 as a potential therapeutic target to modulate the JAK2/STAT3 pathway for the treatment of COPD, with the aim of enhancing lung function, reducing inflammation, and restoring Th17/Treg equilibrium in a clinical context.

Effect of water and sanitation, PM pollution and climate change of COPD and LRIs under different sociodemographic transitions

OBJECTIVES

To estimate the burden of chronic obstructive pulmonary disease (COPD) and lower respiratory tract infections (LRIs) stratified by geographic location, and social-demographic status for 21 regions across the world from 1990 to 2019.

STUDY DESIGN

The analysis utilized data from the Global Burden of Disease (GBD) Study, focusing on mortality and disability-adjusted life years (DALYs) as measures of COPD and LRI burden. Trend analyses using the Joinpoint model were conducted across five socio-demographic index (SDI) quintiles.

METHODS

We investigated the burden of COPD and LRIs employing restricted cubic splines to flexibly identify relationships between DALY rates and SDI. This method allowed for detailed examination of trends over time across different regions and socio-demographic contexts.

RESULTS

From 1990 to 2019, the ASMR of COPD attributed to PM for global and five SDI quintiles decreased 61.80 %, 53.41 %, 63.04 %, 63.00 %, 40.98 %, 12.14 % respectively. In terms of PM Pollution, there was an inverted U-shaped association between the DALY and SDI for COPD, the DALY rate associated with LRIs due to PM pollution exhibited a progressive decline as SDI increased.

CONCLUSION

Even though the trend in mortality and DALY of COPD and LRIs decreased globally, the COPD and LRI burden attributed to PM pollution remains high, particularly in lower SDI quintiles.

The impact of airborne particulate matter-based pollution on the cellular and molecular mechanisms in chronic obstructive pulmonary disease (COPD)

Inhalation of particulate matter (PM), one of the many components of air pollution, is associated with the development and exacerbation of chronic respiratory diseases, such as chronic obstructive pulmonary disease (COPD). COPD is one of the leading causes of global mortality and morbidity, with a paucity of therapeutic options and a significant contributor to global health expenditure. This review aims to provide a mechanistic understanding of the cellular and molecular pathways that lead to the development of COPD following chronic PM exposure. Our review describes how the inhalation of PM can lead to lung parenchymal destruction and cellular senescence due to chronic pulmonary inflammation and oxidative stress. Following inhalation of PM, significant increases in a range of pro-inflammatory cytokines, mediated by the nuclear factor kappa B pathway are reported. This review also highlights how the inhalation of PM can lead to deleterious chronic oxidative stress persisting in the lung post-exposure. Furthermore, our work summarises how PM inhalation can lead to airway remodelling, with increases in pro-fibrotic cytokines and collagen deposition, typical of COPD. This paper also accentuates the interconnection and possible synergism between the pathophysiological mechanisms leading to COPD. Our work emphasises the serious health consequences of PM exposure on respiratory health. Elucidation of the cellular and molecular mechanisms can provide insight into possible therapeutic options. Finally, this review should serve as a stark reminder of the need for genuine action on air pollution to decrease the associated health burden on our growing global population.

Regulatory role of microRNAs in virus-mediated inflammation

Viral infections in humans often cause excessive inflammation. In some viral infections, inflammation can be serious and even fatal, while in other infections it can promote viral clearance. Viruses can escape from the host immune system via regulating inflammatory pathways, thus worsening the illness. MicroRNAs (miRNAs) are tiny non-coding RNA molecules expressed within diverse tissues as well as cells and are engaged in different normal pathological and physiological pathways. Emerging proof suggests that miRNAs can impact innate and adaptive immunity, inflammatory responses, cell invasion, and the progression of viral infections. We discuss some intriguing new findings in the current work, focusing on the impacts of different miRNAs on host inflammatory responses and virus-mediated inflammation. A better understanding of dysregulated miRNAs in viral infections could improve the identification, prevention, and treatment of several serious diseases.

Transcriptome and RNA sequencing analysis of H9C2 cells exposed to diesel particulate matter

Although air pollution has been classified as a risk factor for heart disease, the underlying mechanisms remain nebulous. Therefore, this study investigated the effect of diesel particulate matter (DPM) exposure on cardiomyocytes and identified differentially expressed genes (DEGs) induced by DPM. DPM treatment decreased H9C2 cell viability and increased cytotoxicity. Ten genes showed statistically significant differential expression following treatment with DPM at 25 and 100 μg/ml for 3 h. A total of 273 genes showed statistically significant differential expression following treatment with DPM at 25 and 100 μg/ml for 24 h. Signaling pathway analysis revealed that the DEGs were related to the 'reactive oxygens species,' 'IL-17,' and 'fluid shear stress and atherosclerosis' signaling pathways. Hmox1, Fos, and Fosb genes were significantly upregulated among the selected DEGs. This study identified DPM-induced DEGs and verified the selected genes using qRT-PCR and western blotting. The findings provide insights into the molecular events in cardiomyocytes following exposure to DPM.

Cordyceps militaris Grown on Germinated Rhynchosia nulubilis (GRC) Encapsulated in Chitosan Nanoparticle (GCN) Suppresses Particulate Matter (PM)-Induced Lung Inflammation in Mice

Cordyceps militaris grown on germinated Rhynchosia nulubilis (GRC) exerts various biological effects, including anti-allergic, anti-inflammatory, and immune-regulatory effects. In this study, we investigated the anti-inflammatory effects of GRC encapsulated in chitosan nanoparticles (CN) against particulate matter (PM)-induced lung inflammation. Optimal CN (CN6) (CHI: TPP w/w ratio of 4:1; TPP pH 2) exhibited a zeta potential of +22.77 mV, suitable for GRC encapsulation. At different GRC concentrations, higher levels (60 and 120 mg/mL) led to increased negative zeta potential, enhancing stability. The optimal GRC concentration for maximum entrapment (31.4 ± 1.35%) and loading efficiency (7.6 ± 0.33%) of GRC encapsulated in CN (GCN) was 8 mg/mL with a diameter of 146.1 ± 54 nm and zeta potential of +30.68. In vivo studies revealed that administering 300 mg/kg of GCN significantly decreased the infiltration of macrophages and T cells in the lung tissues of PM-treated mice, as shown by immunohistochemical analysis of CD4 and F4/80 markers. Additionally, GCN ameliorated PM-induced lung tissue damage, inflammatory cell infiltration, and alveolar septal hypertrophy. GCN also decreased total cells and neutrophils, showing notable anti-inflammatory effects in the bronchoalveolar lavage fluid (BALF) from PM-exposed mice, compared to GRC. Next the anti-inflammatory properties of GCN were further explored in PM- and LPS-exposed RAW264.7 cells; it significantly reduced PM- and LPS-induced cell death, NO production, and levels of inflammatory cytokine mRNAs (IL-1β, IL-6, and COX-2). GCN also suppressed NF-κB/MAPK signaling pathways by reducing levels of p-NF-κB, p-ERK, and p-c-Jun proteins, indicating its potential in managing PM-related inflammatory lung disease. Furthermore, GCN significantly reduced PM- and LPS-induced ROS production. The enhanced bioavailability of GRC components was demonstrated by an increase in fluorescence intensity in the intestinal absorption study using FITC-GCN. Our data indicated that GCN exhibited enhanced bioavailability and potent anti-inflammatory and antioxidant effects in cells and in vivo, making it a promising candidate for mitigating PM-induced lung inflammation and oxidative stress.

Periodontal disease: A systemic condition

For decades, periodontitis has been considered to be a local inflammatory disease of the periodontal tissues in the oral cavity. Initially, associations of periodontitis with a multitude of noncommunicable diseases were each studied separately, and relationships were shown. The associations of periodontitis with morbidities, such as cardiovascular diseases, rheumatoid arthritis, diabetes mellitus, respiratory diseases, have been demonstrated. As most such studies were cross-sectional in nature, questions about causality cannot be univocally answered. And periodontitis as an independent risk factor for one systemic disease, becomes even more difficult to assess since recently periodontitis has also been associated with multimorbidity. Periodontitis and many systemic diseases share environmental, lifestyle and genetic risk factors, and share immunopathology. Moreover, suffering from one common noncommunicable disease may increase the susceptibility for another such chronic disease; the systemic effects of one condition may be one of various risk factors for another such disease. The overarching effect of any systemic disease is it causing a pro-inflammatory state in the individual; this has also been shown for periodontitis. Moreover, in periodontitis a prothrombotic state and elevated immunological activity have been shown. As such, when we consider periodontal disease as another systemic disease, it can affect the susceptibility and progression of other systemic diseases, and importantly, vice versa. And with this, it is not surprising that periodontitis is associated with a variety of other noncommunicable diseases. The medical definition of a systemic disease includes diseases that affect different organs and systems. Thus, the aim of this opinion paper is to propose that periodontitis should be considered a systemic disease in its own right and that it affects the individual's systemic condition and wellbeing. The dental and medical profession and researchers alike, should adapt this paradigm shift, advancing periodontal disease out of its isolated anatomical location into the total of chronic noncommunicable diseases, being for some conditions a comorbid disease and, vice versa, comorbidities can affect initiation and progression of periodontal disease.

The impact of PM2.5 on lung function and chronic respiratory diseases: insights from genetic evidence

BACKGROUND

PM2.5 has been associated with various adverse health effects, particularly affecting lung function and chronic respiratory diseases. However, the genetic causality relationship between PM2.5 exposure and lung function as well as chronic respiratory diseases remains poorly understood.

METHOD

We conducted a two-sample Mendelian randomization analysis to investigate the causal impact of PM2.5 on lung function and chronic respiratory diseases. Instrumental variables were carefully selected, with significance thresholds (P < 5 × 10- 8), and linkage disequilibrium with an r2 value below 0.001. Additionally, SNPs with an F-statistic exceeding 10 were included to mitigate potential bias stemming from weak instrumental variables. The primary analytical approach employed the Inverse Variance Weighted method, supplemented by the Weighted Median, MR-Egger, Simple Model, and Weighted Model. Furthermore, pleiotropy and heterogeneity were evaluated through the MR-Egger intercept test and Cochrane's Q test, with a sensitivity analysis conducted using the leave-one-out method.

RESULTS

Eight SNPs significantly associated with PM2.5 exposure were identified as Instrumental variables. Mendelian randomization analysis revealed a significant causal association between PM2.5 exposure and lung function (FEV), with an OR of 0.7284 (95% CI: 0.5799-0.9150). Similarly, PM2.5 exposure demonstrated a substantial causal effect on asthma, with an OR of 1.5280 (95% CI: 1.0470-2.2299). However, no causal association was observed between PM2.5 exposure and chronic obstructive pulmonary disease, with an OR of 1.5176 (95% CI: 0.8294-2.7768).

CONCLUSION

These findings emphasize the necessity for continued research efforts in environmental health to develop effective strategies for the prevention and management of chronic respiratory diseases.

Inflammatory and Immune Mechanisms in COPD: Current Status and Therapeutic Prospects

Background

Chronic obstructive pulmonary disease (COPD) currently ranks among the top three causes of mortality worldwide, presenting as a prevalent and complex respiratory ailment. Ongoing research has underscored the pivotal role of immune function in the onset and progression of COPD. The immune response in COPD patients exhibits abnormalities, characterized by diminished anti-infection capacity due to immune senescence, heightened activation of neutrophils and macrophages, T cell infiltration, and aberrant B cell activity, collectively contributing to airway inflammation and lung injury in COPD.

Objective

This review aimed to explore the pivotal role of the immune system in COPD and its therapeutic potential.

Methods

We conducted a review of immunity and COPD published within the past decade in the Web of Science and PubMed databases, sorting through and summarizing relevant literature.

Results

This article examines the pivotal roles of the immune system in COPD. Understanding the specific functions and interactions of these immune cells could facilitate the development of novel therapeutic strategies and interventions aimed at controlling inflammation, enhancing immune function, and mitigating the impact of respiratory infections in COPD patients.

What every clinician should know about inflammation in COPD

Inflammation drives COPD pathogenesis and exacerbations. Although the conceptual framework and major players in the inflammatory milieu of COPD have been long established, the nuances of cellular interactions and the etiological differences that create heterogeneity in inflammatory profiles and treatment response continue to be revealed. This wealth of data and understanding is not only a boon to the researcher but also provides guidance to the clinician, moving the field closer to precision medicine. It is through this lens that this review seeks to describe the inflammatory processes at play in COPD, relating inflammation to pathological and functional changes, identifying patient-specific and disease-related factors that may influence clinical observations, and providing current insights on existing and emerging anti-inflammatory treatments and treatment targets, including biological therapies and phosphodiesterase (PDE) inhibitors.

Down-regulation of RTEL1 Improves M1/M2 Macrophage Polarization by Promoting SFRP2 in Fibroblasts-derived Exosomes to Alleviate COPD

Chronic obstructive pulmonary disease (COPD) is a common chronic respiratory disease worldwide. Macrophage polarization plays a substantial role in the pathogenesis of COPD. This study is aimed to explore the regulatory mechanism of regulator of telomere elongation 1 (RTEL1) in COPD. COPD model mouse was conducted by cigarette smoke (CS). The pathological features of lung in mice were observed by histological staining. After extracting exosomes, macrophages were co-cultured with fibroblasts-derived exosomes. Then, the effects of RTEL1 and exosomal secreted frizzled-related protein 2 (SFRP2) on macrophage proliferation, inflammation, apoptosis, and M1, M2 macrophage polarization (iNOS and CD206) were evaluated by cell counting kit-8, EdU assay, enzyme-linked immuno sorbent assay, and western blotting, respectively. CS-induced COPD model mouse was successfully constructed. Through in vitro experiments, knockdown of RTEL1 inhibited macrophage proliferation, inflammation (MMP9, IL-1β and TNF-α), and promoted apoptosis (Bax, cleaved-caspase3, Bcl-2) in CS extract-induced lung fibroblasts. Meanwhile, RTEL1 knockdown promoted M1 and suppressed M2 macrophage polarization in COPD. Additionally, silencing SFRP2 in fibroblasts-derived exosomes reversed the effects of RTEL1 knockdown on proliferation, inflammation, apoptosis, and M1, M2 macrophage polarization. Collectively, down-regulation of RTEL1 improved M1/M2 macrophage polarization by promoting SFRP2 in fibroblasts-derived exosomes to alleviate CS-induced COPD.

Decoding LncRNA in COPD: Unveiling Prognostic and Diagnostic Power and Their Driving Role in Lung Cancer Progression

Chronic obstructive pulmonary disease (COPD) and lung cancer represent formidable challenges in global health, characterized by intricate pathophysiological mechanisms and multifaceted disease progression. This comprehensive review integrates insights from diverse perspectives to elucidate the intricate roles of long non-coding RNAs (lncRNAs) in the pathogenesis of COPD and lung cancer, focusing on their diagnostic, prognostic, and therapeutic implications. In the context of COPD, dysregulated lncRNAs, such as NEAT1, TUG1, MALAT1, HOTAIR, and GAS5, emerge as pivotal regulators of genes involved in the disease pathogenesis and progression. Their identification, profiling, and correlation with the disease severity present promising avenues for prognostic and diagnostic applications, thereby shaping personalized disease interventions. These lncRNAs are also implicated in lung cancer, underscoring their multifaceted roles and therapeutic potential across both diseases. In the domain of lung cancer, lncRNAs play intricate modulatory roles in disease progression, offering avenues for innovative therapeutic approaches and prognostic indicators. LncRNA-mediated immune responses have been shown to drive lung cancer progression by modulating the tumor microenvironment, influencing immune cell infiltration, and altering cytokine production. Their dysregulation significantly contributes to tumor growth, metastasis, and chemo-resistance, thereby emphasizing their significance as therapeutic targets and prognostic markers. This review summarizes the transformative potential of lncRNA-based diagnostics and therapeutics for COPD and lung cancer, offering valuable insights into future research directions for clinical translation and therapeutic development.

Oxidative potential of particulate matter and its association to respiratory health endpoints in high-altitude cities in Bolivia

Exposure to particulate matter (PM) pollution is a significant health risk, driving the search for innovative metrics that more accurately reflect the potential harm to human health. Among these, oxidative potential (OP) has emerged as a promising health-based metric, yet its application and relevance across different environments remain to be further explored. This study, set in two high-altitude Bolivian cities, aims to identify the most significant sources of PM-induced oxidation in the lungs and assess the utility of OP in assessing PM health impacts. Utilizing two distinct assays, OPDTT and OPDCFH, we measured the OP of PM samples, while also examining the associations between PM mass, OP, and black carbon (BC) concentrations with hospital visits for acute respiratory infections (ARI) and pneumonia over a range of exposure lags (0-2 weeks) using a Poisson regression model adjusted for meteorological conditions. The analysis also leveraged Positive Matrix Factorization (PMF) to link these health outcomes to specific PM sources, building on a prior source apportionment study utilizing the same dataset. Our findings highlight anthropogenic combustion, particularly from traffic and biomass burning, as the primary contributors to OP in these urban sites. Significant correlations were observed between both OPDTT and PM2.5 concentration exposure and ARI hospital visits, alongside a notable association with pneumonia cases and OPDTT levels. Furthermore, PMF analysis demonstrated a clear link between traffic-related pollution and increased hospital admissions for respiratory issues, affirming the health impact of these sources. These results underscore the potential of OPDTT as a valuable metric for assessing the health risks associated with acute PM exposure, showcasing its broader application in environmental health studies.

New markers in chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD), a global healthcare and socioeconomic burden, is a multifaceted respiratory disorder that results in substantial decline in health status and life quality. Acute exacerbations of the disease contribute significantly to increased morbidity and mortality. Consequently, the identification of reliable and effective biomarkers for rapid diagnosis, prediction, and prognosis of exacerbations is imperative. In addition, biomarkers play a crucial role in monitoring responses to therapeutic interventions and exploring innovative treatment strategies. Although established markers such as CRP, fibrinogen and neutrophil count are routinely used, a universal marker is lacking. Fortunately, an increasing number of studies based on next generation analytics have explored potential biomarkers in COPD. Here we review those advances and the need for standardized validation studies in the appropriate clinical setting.

Guggulsterone protects against cigarette smoke-induced COPD linked lung inflammation

Recently, we have shown that guggulsterone is the principal constituent responsible for protective effects of Commiphora wightii against elastase-induced chronic obstructive pulmonary disease (COPD)-linked inflammation/emphysema. Given that cigarette smoke (CS) exposure is a primary risk factor for COPD and beneficial effects of guggulsterone have not been investigated in CS-induced COPD-linked lung inflammation. The present work was designed to validate the potential of guggulsterone in amelioration of COPD-linked lung inflammation by using a CS-based mouse model of the condition. Male BALB/c mice were exposed to 9 cigarettes/day with 1 h interval for 4 days daily. Guggulsterone was administered daily at a dose of 10 mg/kg orally for 4 consecutive days, 1 h before initiation of CS exposure. Mice were subjected to measurement of lung function followed by procurement of bronchoalveolar lavage fluid (BALF)/lung tissue. BALF was analyzed for inflammatory cells and pro-inflammatory cytokines. Lung tissue was subjected to RT-PCR for gene expression analysis. Data showed that CS exposure resulted in a significant increase in total BALF cells, predominantly neutrophils, and macrophages. Interestingly, guggulsterone administration significantly blunted CS-induced inflammation as reflected by reduced neutrophil and macrophage count. Further, the compound inhibited CS-induced gene expression of pro-inflammatory mediators TNF-α/ IL-1β/ G-CSF/and KC in lungs along with the production of pro-inflammatory mediators TNF-α/ IL-1β/ IL-6/ G-CSF/ KC/and MCP-1 in BALF. Further, guggulsterone improved the lung function parameters upon CS exposure. Analysis of mRNA expression of matrix metalloproteinase (MMP)-9 and tissue inhibitor of matrix metalloproteinase (TIMP)-1 suggests that guggulsterone may restore the fine balance between matrix-degrading proteases and its inhibitor in lung tissue upon CS exposure, which may contribute in the development of emphysema at later stages. Overall, our data show that guggulsterone protects against CS-induced COPD-linked lung inflammation by modulating relevant molecular players. Based on the potential effects of guggulsterone in the amelioration of CS-induced lung inflammation, we speculate that guggulsterone might alter chronic CS-induced emphysema.

Paeoniflorin attenuates particulate matter-induced acute lung injury by inhibiting oxidative stress and NLRP3 inflammasome-mediated pyroptosis through activation of the Nrf2 signaling pathway

Particulate matter (PM), the main component of air pollutants, emerges as a research hotspot, especially in the area of respiratory diseases. Paeoniflorin (PAE), known as anti-inflammatory and immunomodulatory effects, has been reported to alleviate acute lung injury (ALI). However, the effect of PAE on PM-induced ALI and the underlying mechanisms are still unclear yet. In this study, we established the PM-induced ALI model using C57BL/6J mice and BEAS-2B cells to explore the function of PAE. In vivo, mice were intraperitoneally injected with PAE (100 mg/kg) or saline 1 h before instilled with 4 mg/kg PM intratracheally and were euthanized on the third day. For lung tissues, HE staining and TUNEL staining were used to evaluate the degree of lung injury, ELISA assay was used to assess inflammatory mediators and oxidative stress level, Immunofluorescence staining and western blotting were applied to explore the role of pyroptosis and Nrf2 signaling pathway. In vitro, BEAS-2B cells were pretreated with 100 μM PAE before exposure to 200 μg/ml PM and were collected after 24h for the subsequent experiments. TUNEL staining, ROS staining, and western blotting were conducted to explore the underlying mechanisms of PAE on PM-induced ALI. According to the results, PAE can attenuate the degree of PM-induced ALI in mice and reduce PM-induced cytotoxicity in BEAS-2B cells. PAE can relieve PM-induced excessive oxidative stress and NLRP3 inflammasome-mediated pyroptosis. Additionally, PAE can also activate Nrf2 signaling pathway and inhibition of Nrf2 signaling pathway can impair the protective effect of PAE by aggravating oxidative stress and pyroptosis. Our findings demonstrate that PAE can attenuate PM-induced ALI by inhibiting oxidative stress and NLRP3 inflammasome-mediated pyroptosis, which is mediated by Nrf2 signaling pathway.

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.

Lixisenatide ameliorated lipopolysaccharide (LPS)-induced expression of mucin and inflammation in bronchial epithelial cells

Chronic obstructive pulmonary disease (COPD) induces serious social and economic burdens due to its high disability and mortality, the pathogenesis of which is highly involved with inflammation, oxidative stress (OS), and mechanism of mucin 5AC (MUC5AC) secretion. Lixisenatide is a selective glucagon-like peptide 1 receptor agonist recently reported to have anti-inflammatory properties. Our study will focus on the potential impact of lixisenatide on lipopolysaccharide (LPS)-induced mucin secretion and inflammation in 16 human bronchial epithelial (16HBE) cells to check its potential function in COPD. 16HBE cells were treated with LPS, with or without lixisenatide (10 and 20 nM) for 1 day. Remarkably declined cell viability, enhanced lactate dehydrogenase release, activated OS, and elevated release of inflammatory cytokines were observed in LPS-treated 16HBE cells, accompanied by the activation of nuclear factor-κB signaling, all of which were signally reversed by lixisenatide. Moreover, elevated expression and release of MUC5AC were observed in LPS-treated 16HBE cells but were markedly repressed by lixisenatide. Furthermore, the repressed nuclear factor erythroid 2-related factor 2 (Nrf2) level in LPS-treated 16HBE cells was notably rescued by lixisenatide. Lastly, following the knockdown of Nrf2, the protective function of lixisenatide on LPS-triggered MUC5AC release in 16HBE cells was significantly abrogated. Collectively, lixisenatide ameliorated LPS-induced expression of mucin and inflammation in bronchial epithelial cells by regulating Nrf2.

Multiomics was used to clarify the mechanism by which air pollutants affect chronic obstructive pulmonary disease: A human cohort study

Exposure to air pollutants has been associated with various adverse health outcomes, including chronic obstructive pulmonary disease (COPD). However, the precise underlying mechanism by which air pollution impacts COPD through remains insufficiently understood. To elucidated the molecular mechanism by which air pollutant exposure contributes to alterations in the gut microbiome and metabolism in AECOPD patients, we employed metagenomics and untargeted metabolomics to analyse the gut microbial, faecal, and serum metabolites. The correlations among air pollutants, gut microbes, serum metabolites, and blood biochemical markers were assessed using generalised additive mixed models and Spearman correlation analysis. The findings revealed that for every 10 μg/m3 increase in PM2.5 concentration, the α-diversity of the gut flora decreased by 2.16% (95% CI: 1.80%-2.53%). We found seven microorganisms that were significantly associated with air pollutants, of which Enterococcus faecium, Bacteroides fragilis, Ruthenibacterium lactatiformans, and Subdoligranulum sp.4_3_54A2FAA were primarily associated with glycolysis. We identified 13 serum metabolites and 17 faecal metabolites significantly linked to air pollutants. Seven of these metabolites, which were strongly associated with air pollutants and blood biochemical indices, were found in both serum and faecal samples. Some of these metabolites, such as 2,5-furandicarboxylic acid, C-8C1P and melatonin, were closely associated with disturbances in lipid and fatty acid metabolism in AECOPD patients. These findings underscore the impact of air pollutants on overall metabolism based on influencing gut microbes and metabolites in AECOPD patients. Moreover, these altered biomarkers establish the biologic connection between air pollutant exposure and AECOPD outcomes.The identification of pertinent biomarkers provides valuable insights for the development of precision COPD prevention strategies.

Endothelial progenitor cells systemic administration alleviates multi-organ senescence by down-regulating USP7/p300 pathway in chronic obstructive pulmonary disease

BACKGROUND

Chronic obstructive pulmonary disease (COPD) has impacted approximately 390 million people worldwide and the morbidity is increasing every year. However, due to the poor treatment efficacy of COPD, exploring novel treatment has become the hotpot of study on COPD. Endothelial progenitor cells (EPCs) aging is a possible molecular way for COPD development. We aimed to explore the effector whether intravenous administration of EPCs has therapeutic effects in COPD mice.

METHODS

COPD mice model was induced by cigarette smoke exposure and EPCs were injected intravenously to investigate their effects on COPD mice. At day 127, heart, liver, spleen, lung and kidney tissues of mice were harvested. The histological effects of EPCs intervention on multiple organs of COPD mice were detected by morphology assay. Quantitative real-time PCR and Western blotting were used to detect the effect of EPCs intervention on the expression of multi-organ senescence-related indicators. And we explored the effect of EPCs systematically intervening on senescence-related USP7/p300 pathway.

RESULTS

Compared with COPD group, senescence-associated β-galactosidase activity was decreased, protein and mRNA expression of p16 was down-regulated, while protein and mRNA expression of cyclin D1 and TERT were up-regulated of multiple organs, including lung, heart, liver, spleen and kidney in COPD mice after EPCs system intervention. But the morphological alterations of the tissues described above in COPD mice failed to be reversed. Mechanistically, EPCs systemic administration inhibited the expression of mRNA and protein of USP7 and p300 in multiple organs of COPD mice, exerting therapeutic effects.

CONCLUSIONS

EPCs administration significantly inhibited the senescence of multiple organs in COPD mice via down-regulating USP7/p300 pathway, which presents a possibility of EPCs therapy for COPD.

RETRO-POPE: A Retrospective, Multicenter, Real-World Study of All-Cause Mortality in COPD

Purpose

The Phenotypes of COPD in Central and Eastern Europe (POPE) study assessed the prevalence and clinical characteristics of four clinical COPD phenotypes, but not mortality. This retrospective analysis of the POPE study (RETRO-POPE) investigated the relationship between all-cause mortality and patient characteristics using two grouping methods: clinical phenotyping (as in POPE) and Burgel clustering, to better identify high-risk patients.

Patients and Methods

The two largest POPE study patient cohorts (Czech Republic and Serbia) were categorized into one of four clinical phenotypes (acute exacerbators [with/without chronic bronchitis], non-exacerbators, asthma-COPD overlap), and one of five Burgel clusters based on comorbidities, lung function, age, body mass index (BMI) and dyspnea (very severe comorbid, very severe respiratory, moderate-to-severe respiratory, moderate-to-severe comorbid/obese, and mild respiratory). Patients were followed-up for approximately 7 years for survival status.

Results

Overall, 801 of 1,003 screened patients had sufficient data for analysis. Of these, 440 patients (54.9%) were alive and 361 (45.1%) had died at the end of follow-up. Analysis of survival by clinical phenotype showed no significant differences between the phenotypes (P=0.211). However, Burgel clustering demonstrated significant differences in survival between clusters (P<0.001), with patients in the "very severe comorbid" and "very severe respiratory" clusters most likely to die. Overall survival was not significantly different between Serbia and the Czech Republic after adjustment for age, BMI, comorbidities and forced expiratory volume in 1 second (hazard ratio [HR] 0.80, 95% confidence interval [CI] 0.65-0.99; P=0.036 [unadjusted]; HR 0.88, 95% CI 0.7-1.1; P=0.257 [adjusted]). The most common causes of death were respiratory-related (36.8%), followed by cardiovascular (25.2%) then neoplasm (15.2%).

Conclusion

Patient clusters based on comorbidities, lung function, age, BMI and dyspnea were more likely to show differences in COPD mortality risk than phenotypes defined by exacerbation history and presence/absence of chronic bronchitis and/or asthmatic features.

Association between systemic immune-inflammation index and chronic obstructive pulmonary disease: a population-based study

BACKGROUND

The Systemic Immune-Inflammation Index (SII) is a quantitative measurement of the systemic immune-inflammatory response in the human body. The SII has been shown to have prognostic value in various clinical settings, including critical illness, sepsis, and cancer. Its role in chronic obstructive pulmonary disease (COPD) remains unclear and requires further investigation.

METHODS

We analyzed demographic data from 16,636 participants in the National Health and Nutrition Examination Survey. Logistic regression analysis was performed to assess the correlation between COPD, lung function, chronic respiratory symptoms and SII. We used Cox proportional hazards (PH) model to analyze the relationship between SII and mortality in COPD patients and healthy individuals. We used propensity score matching (PSM) method to match the COPD population with similar baseline levels with the normal population to further analyze the correlation between SII and COPD.

RESULTS

We recruited 16,636 participants, ages 40 and above, for the study. A multivariable logistic regression analysis revealed that a higher SII level was independently associated with an elevated likelihood of COPD (Odds Ratio (OR) = 1.449; 95% Confidence Interval (CI): 1.252-1.676, P < 0.0001) after controlling for all other factors. Results of subgroup analysis showed a significant positive correlation between SII and COPD in different age groups, gender, Body Mass Index, smoking status, and those with a history of hypertension. The SII index had positive correlation with COPD after PSM (OR = 1.673; 95%CI: 1.443-1.938). After full adjustment, an increase in the SII is associated with a higher all-cause mortality rate. The hazard ratio (HR) with a 95% CI in the general population, COPD patients, and healthy individuals are 1.161 (1.088, 1.239), 1.282 (1.060, 1.550), and 1.129 (1.055, 1.207), respectively.

CONCLUSIONS

Higher SII levels are linked to higher prevalence of COPD. COPD patients with a higher SII levels have a higher risk of all-cause mortality. Additional large-scale, long-term studies are necessary to confirm these results.

COPD Exacerbation: Why It Is Important to Avoid ICU Admission

Chronic obstructive pulmonary disease (COPD) is one of the major causes of morbidity and mortality worldwide. Hospitalization due to acute exacerbations of COPD (AECOPD) is a relevant health problem both for its impact on disease outcomes and on health system resources. Severe AECOPD causing acute respiratory failure (ARF) often requires admission to an intensive care unit (ICU) with endotracheal intubation and invasive mechanical ventilation. AECOPD also acts as comorbidity in critically ill patients; this condition is associated with poorer prognoses. The prevalence reported in the literature on ICU admission rates ranges from 2 to 19% for AECOPD requiring hospitalization, with an in-hospital mortality rate of 20-40% and a re-hospitalization rate for a new severe event being 18% of the AECOPD cases admitted to ICUs. The prevalence of AECOPD in ICUs is not properly known due to an underestimation of COPD diagnoses and COPD misclassifications in administrative data. Non-invasive ventilation in acute and chronic respiratory failure may prevent AECOPD, reducing ICU admissions and disease mortality, especially when associated with a life-threating episode of hypercapnic ARF. In this review, we report on up to date evidence from the literature, showing how improving the knowledge and management of AECOPD is still a current research issue and clinical need.

The Tobacco Smoke Component, Acrolein, as a Major Culprit in Lung Diseases and Respiratory Cancers: Molecular Mechanisms of Acrolein Cytotoxic Activity

Acrolein, a highly reactive unsaturated aldehyde, is a ubiquitous environmental pollutant that seriously threatens human health and life. Due to its high reactivity, cytotoxicity and genotoxicity, acrolein is involved in the development of several diseases, including multiple sclerosis, neurodegenerative diseases such as Alzheimer’s disease, cardiovascular and respiratory diseases, diabetes mellitus and even the development of cancer. Traditional tobacco smokers and e-cigarette users are particularly exposed to the harmful effects of acrolein. High concentrations of acrolein have been found in both mainstream and side-stream tobacco smoke. Acrolein is considered one of cigarette smoke’s most toxic and harmful components. Chronic exposure to acrolein through cigarette smoke has been linked to the development of asthma, acute lung injury, chronic obstructive pulmonary disease (COPD) and even respiratory cancers. This review addresses the current state of knowledge on the pathological molecular mechanisms of acrolein in the induction, course and development of lung diseases and cancers in smokers.

The Emerging Role of Autophagy as a Target of Environmental Pollutants: An Update on Mechanisms

Autophagy is an evolutionarily conserved cellular system crucial for cellular homeostasis that protects cells from a broad range of internal and extracellular stresses. Autophagy decreases metabolic load and toxicity by removing damaged cellular components. Environmental contaminants, particularly industrial substances, can influence autophagic flux by enhancing it as a protective response, preventing it, or converting its protective function into a pro-cell death mechanism. Environmental toxic materials are also notorious for their tendency to bioaccumulate and induce pathophysiological vulnerability. Many environmental pollutants have been found to influence stress which increases autophagy. Increasing autophagy was recently shown to improve stress resistance and reduce genetic damage. Moreover, suppressing autophagy or depleting its resources either increases or decreases toxicity, depending on the circumstances. The essential process of selective autophagy is utilized by mammalian cells in order to eliminate particulate matter, nanoparticles, toxic metals, and smoke exposure without inflicting damage on cytosolic components. Moreover, cigarette smoke and aging are the chief causes of chronic obstructive pulmonary disease (COPD)-emphysema; however, the disease's molecular mechanism is poorly known. Therefore, understanding the impacts of environmental exposure via autophagy offers new approaches for risk assessment, protection, and preventative actions which will counter the harmful effects of environmental contaminants on human and animal health.

The Effects and Pathogenesis of PM2.5 and Its Components on Chronic Obstructive Pulmonary Disease

Chronic obstructive pulmonary disease (COPD), a heterogeneous disease, is the leading cause of death worldwide. In recent years, air pollution, especially particulate matter (PM), has been widely studied as a contributing factor to COPD. As an essential component of PM, PM2.5 is associated with COPD prevalence, morbidity, and acute exacerbations. However, the specific pathogenic mechanisms were still unclear and deserve further research. The diversity and complexity of PM2.5 components make it challenging to get its accurate effects and mechanisms for COPD. It has been determined that the most toxic PM2.5 components are metals, polycyclic aromatic hydrocarbons (PAHs), carbonaceous particles (CPs), and other organic compounds. PM2.5-induced cytokine release and oxidative stress are the main mechanisms reported leading to COPD. Nonnegligibly, the microorganism in PM 2.5 may directly cause mononuclear inflammation or break the microorganism balance contributing to the development and exacerbation of COPD. This review focuses on the pathophysiology and consequences of PM2.5 and its components on COPD.

Dental Pulp Stem Cells Ameliorate Elastase-Induced Pulmonary Emphysema by Regulating Inflammation and Oxidative Stress

Background

Dental pulp stem cells (DPSCs) are considered excellent candidates for stem cell-based tissue regeneration. In this study, we aimed to evaluate the therapeutic effect of DPSCs in a mouse chronic obstructive pulmonary disease (COPD) model and to explore whether DPSCs reduce lung inflammation and oxidative stress by regulating the nuclear factor erythroid-2 related factor-2 (Nrf2) signaling pathway.

Methods

DPSCs were isolated from dental pulp tissue by the tissue block method. Emphysema of C57BL/6 mice was induced by endotracheal administration of porcine pancreatic elastase (PPE). Then, the DPSCs were injected into the lungs through the trachea, and after 3 weeks of stem cell treatment, various efficacy tests were performed. The AniRes2005 animal lung function analytic system was used to detect lung function. Hematoxylin-eosin staining (H&E) and Victoria blue staining was used to assess emphysema severity. The animal tissues were detected by Western blot, RT‒qPCR, ELISA and oxidative stress related detection.

Results

In experimental COPD models, DPSCs transplantation improved lung function, body weight, and emphysema-like changes better than bone marrow mesenchyml stem cells (BM-MSCs). Compared with the COPD group, the levels of IL-1β, TNF-α and IL-6 in lung tissue and bronchoalveolar lavage fluid (BALF) were decreased after transplantation of DPSCs. DPSCs may be associated with lower malondialdehyde (MDA) levels, and higher catalase (CAT) and glutathione (GSH) levels. Western blot results showed that the expression of Nrf2 and its downstream factors increased after transplantation of DPSCs.

Conclusion

The current study showed that DPSCs had good performance in the treatment of a mouse COPD model and could be a promising option for stem cell therapy. DPSCs may play antioxidant and anti-inflammatory roles in COPD by activating the Nrf2 signaling pathway.

Hydrogen Sulfide: A Gaseous Mediator and Its Key Role in Programmed Cell Death, Oxidative Stress, Inflammation and Pulmonary Disease

Hydrogen sulfide (H2S) has been acknowledged as a novel gaseous mediator. The metabolism of H2S in mammals is tightly controlled and is mainly achieved by many physiological reactions catalyzed by a suite of enzymes. Although the precise actions of H2S in regulating programmed cell death, oxidative stress and inflammation are yet to be fully understood, it is becoming increasingly clear that H2S is extensively involved in these crucial processes. Since programmed cell death, oxidative stress and inflammation have been demonstrated as three important mechanisms participating in the pathogenesis of various pulmonary diseases, it can be inferred that aberrant H2S metabolism also functions as a critical contributor to pulmonary diseases, which has also been extensively investigated. In the meantime, substantial attention has been paid to developing therapeutic approaches targeting H2S for pulmonary diseases. In this review, we summarize the cutting-edge knowledge on the metabolism of H2S and the relevance of H2S to programmed cell death, oxidative stress and inflammation. We also provide an update on the crucial roles played by H2S in the pathogenesis of several pulmonary diseases. Finally, we discuss the perspective on targeting H2S metabolism in the treatment of pulmonary diseases.

Short-Term Associations between Size-Fractioned Particles and Cardiopulmonary Function in COPD Patients: A Panel Study in Shanghai, China, during 2014-2021

It remains unknown which size fractions dominate the adverse cardiopulmonary effects of particulate matter (PM). Therefore, this study aimed to explore the differential associations between size-fractioned particle number concentrations (PNCs) and cardiopulmonary function measures, including the forced expiratory volume in one second (FEV₁), the forced vital capacity (FVC), and the left ventricular ejection fraction (LVEF). We conducted a panel study among 211 patients with chronic obstructive pulmonary disease (COPD) in Shanghai, China, between January 2014 and December 2021. We applied linear mixed-effect models to determine the associations between cardiopulmonary function measures and PNCs ranging from 0.01 to 10 μm in diameter. Generally, only particles <1 μm showed significant associations, i.e., ultrafine particles (UFPs, <0.1 μm) for FVC and particles ranging from 0.1 to 1 µm for FEV₁ and LVEF. An interquartile range (IQR) increment in UFP was associated with decreases of 78.4 mL in FVC. PNC_0.1-0.3 and PNC_0.3-1 corresponded to the strongest effects on FEV₁ (119.5 mL) and LVEF (1.5%) per IQR increment. Particles <1 µm might dominate the cardiopulmonary toxicity of PM, but UFPs might not always have the strongest effect. Tailored regulations towards particles <1 µm should be intensified to reduce PM pollution and protect vulnerable populations.