Cigarette smoke exposure exacerbates lung inflammation and compromises immunity to bacterial infection

The impact of smoking on bronchiectasis and its comorbidities

INTRODUCTION

Bronchiectasis, characterized by irreversible bronchial dilatation, is a growing global health concern with significant morbidity. This review delves into the intricate relationship between smoking and bronchiectasis, examining its epidemiology, pathophysiology, clinical manifestations, and therapeutic approaches. Our comprehensive literature search on PubMed utilized MESH terms including 'smoking,' 'smoking cessation,' 'bronchiectasis,' and 'comorbidities' to gather relevant studies.

AREAS COVERED

This review emphasizes the role of smoking in bronchiectasis development and exacerbation by compromising airways and immune function. Interconnected comorbidities, including chronic obstructive pulmonary disease, asthma, and gastroesophageal reflux disease, create a detrimental cycle affecting patient outcomes. Despite limited studies on smoking cessation in bronchiectasis, the review stresses its importance. Advocating for tailored cessation programs, interventions like drainage, bronchodilators, and targeted antibiotics are crucial to disrupting the inflammatory-infection-widening cycle.

EXPERT OPINION

The importance of smoking cessation in bronchiectasis management is paramount due to its extensive negative impact on related conditions. Proactive cessation programs utilizing technology and targeted education for high-risk groups aim to reduce smoking's impact on disease progression and related comorbidities. In conclusion, a personalized approach centered on smoking cessation is deemed vital for bronchiectasis, aiming to improve outcomes and enhance patients' quality of life in the face of this complex respiratory condition.

Challenges in current inhalable tobacco toxicity assessment models: A narrative review

Emerging tobacco products such as electronic nicotine delivery systems (ENDS) and heated tobacco products (HTPs) have a dynamic landscape and are becoming widely popular as they claim to offer a low-risk alternative to conventional smoking. Most pre-clinical laboratories currently exploit in vitro, ex vivo, and in vivo experimental models to assess toxicological outcomes as well as to develop risk-estimation models. While most laboratories have produced a wide range of cell culture and mouse model data utilizing current smoke/aerosol generators and standardized puffing profiles, much variation still exists between research studies, hindering the generation of usable data appropriate for the standardization of these tobacco products. In this review, we discuss current state-of-the-art in vitro and in vivo models and their challenges, as well as insights into risk estimation of novel products and recommendations for toxicological parameters for reporting, allowing comparability of the research studies between laboratories, resulting in usable data for regulation of these products before approval by regulatory authorities.

The activation of the AIM2 inflammasome after cigarette smoke exposure leads to an immunosuppressive lung microenvironment

Cigarette smoke is widely known as contributing to chronic inflammation underlying several airway diseases, such as chronic obstructive pulmonary disease (COPD) and lung cancer. In our previous studies we found that the lung of both COPD and cancer patients were characterized by the presence and activation of the AIM2 inflammasome. Here, we wanted to investigate the upstream step during the establishment of chronic lung inflammation after cigarette smoke exposure. We took advantage of a mouse model of smoking exposure and public scRNAseq data. We found that AIM2 mRNA was expressed in both alveolar type II, B cells, T regulatory (Treg) and macrophages detected in the lung of non-smokers (n = 4) and smokers (n = 3). The activation of AIM2 in smoking mice by using PolydA:dT did not alter cigarette-smoke-induced alveoli enlargement and mucus production, rather it induced higher recruitment of immunosuppressive cells, such as non-active dendritic cells (DCs), Arginase I+ macrophages, myeloid-derived suppressor cells (MDSC) and Tregs. In addition, the inflammatory environment after AIM2 activation in smoking mice was characterized by higher levels of IL-1α, IL-1β, IL-33, TNFα, LDH, IL-10 and TGFβ. This scenario was not altered after the pharmacological inhibition of both caspase-1 and STING pathway. In conclusion, these data suggest that chronic inflammation after cigarette smoke exposure is associated with AIM2 activation, which could lead towards cigarette smoke-associated lung diseases.

Rieske Iron-Sulfur Protein Mediates Pulmonary Hypertension Following Nicotine/Hypoxia Coexposure

The high mortality rate in patients with chronic obstructive pulmonary disease (COPD) may be due to pulmonary hypertension (PH). These diseases are highly associated with cigarette smoke and its key component nicotine. Here, we created a novel animal model of PH using coexposure to nicotine (or cigarette smoke) and hypoxia. This heretofore unreported model showed significant early-onset pulmonary vasoremodeling and PH. Using newly generated mice with complementary smooth muscle-specific Rieske iron-sulfur protein (RISP) gene knockout and overexpression, we demonstrate that RISP is critically involved in promoting pulmonary vasoremodeling and PH, which are implemented by oxidative ataxia telangiectasia-mutated-mediated DNA damage and NF-κB-dependent inflammation in a reciprocal positive mechanism. Together, our findings establish for the first time an animal model of hypoxia-induced early-onset PH in which mitochondrial RISP-dependent DNA damage and NF-κB inflammation play critical roles in vasoremodeling. Specific therapeutic targets for RISP and related oxidative stress-associated signaling pathways may create unique and effective treatments for PH, chronic obstructive pulmonary disease, and their complications.

Oro-Respiratory Dysbiosis and Its Modulatory Effect on Lung Mucosal Toxicity during Exposure or Co-Exposure to Carbon Nanotubes and Cigarette Smoke

The oro-respiratory microbiome is impacted by inhalable exposures such as smoking and has been associated with respiratory health conditions. However, the effect of emerging toxicants, particularly engineered nanoparticles, alone or in co-exposure with smoking, is poorly understood. Here, we investigated the impact of sub-chronic exposure to carbon nanotube (CNT) particles, cigarette smoke extract (CSE), and their combination. The oral, nasal, and lung microbiomes were characterized using 16S rRNA-based metagenomics. The exposures caused the following shifts in lung microbiota: CNT led to a change from Proteobacteria and Bacteroidetes to Firmicutes and Tenericutes; CSE caused a shift from Proteobacteria to Bacteroidetes; and co-exposure (CNT+CSE) had a mixed effect, maintaining higher numbers of Bacteroidetes (due to the CNT effect) and Tenericutes (due to the CSE effect) compared to the control group. Oral microbiome analysis revealed an abundance of the following genera: Acinetobacter (CNT), Staphylococcus, Aggregatibacter, Allobaculum, and Streptococcus (CSE), and Alkalibacterium (CNT+CSE). These proinflammatory microbial shifts correlated with changes in the relative expression of lung mucosal homeostasis/defense proteins, viz., aquaporin 1 (AQP-1), surfactant protein A (SP-A), mucin 5b (MUC5B), and IgA. Microbiota depletion reversed these perturbations, albeit to a varying extent, confirming the modulatory role of oro-respiratory dysbiosis in lung mucosal toxicity. This is the first demonstration of specific oro-respiratory microbiome constituents as potential modifiers of toxicant effects in exposed lungs.

Smoking changes adaptive immunity with persistent effects

Individuals differ widely in their immune responses, with age, sex and genetic factors having major roles in this inherent variability1-6. However, the variables that drive such differences in cytokine secretion-a crucial component of the host response to immune challenges-remain poorly defined. Here we investigated 136 variables and identified smoking, cytomegalovirus latent infection and body mass index as major contributors to variability in cytokine response, with effects of comparable magnitudes with age, sex and genetics. We find that smoking influences both innate and adaptive immune responses. Notably, its effect on innate responses is quickly lost after smoking cessation and is specifically associated with plasma levels of CEACAM6, whereas its effect on adaptive responses persists long after individuals quit smoking and is associated with epigenetic memory. This is supported by the association of the past smoking effect on cytokine responses with DNA methylation at specific signal trans-activators and regulators of metabolism. Our findings identify three novel variables associated with cytokine secretion variability and reveal roles for smoking in the short- and long-term regulation of immune responses. These results have potential clinical implications for the risk of developing infections, cancers or autoimmune diseases.

Caspase-8 activation by cigarette smoke induces pro-inflammatory cell death of human macrophages exposed to lipopolysaccharide

Cigarette smoking impairs the lung innate immune response making smokers more susceptible to infections and severe symptoms. Dysregulation of cell death is emerging as a key player in chronic inflammatory conditions. We have recently reported that short exposure of human monocyte-derived macrophages (hMDMs) to cigarette smoke extract (CSE) altered the TLR4-dependent response to lipopolysaccharide (LPS). CSE caused inhibition of the MyD88-dependent inflammatory response and activation of TRIF/caspase-8/caspase-1 pathway leading to Gasdermin D (GSDMD) cleavage and increased cell permeability. Herein, we tested the hypothesis that activation of caspase-8 by CSE increased pro-inflammatory cell death of LPS-stimulated macrophages. To this purpose, we measured apoptotic and pyroptotic markers as well as the expression/release of pro-inflammatory mediators in hMDMs exposed to LPS and CSE, alone or in combination, for 6 and 24 h. We show that LPS/CSE-treated hMDMs, but not cells treated with CSE or LPS alone, underwent lytic cell death (LDH release) and displayed apoptotic features (activation of caspase-8 and -3/7, nuclear condensation, and mitochondrial membrane depolarization). Moreover, the negative regulator of caspase-8, coded by CFLAR gene, was downregulated by CSE. Activation of caspase-3 led to Gasdermin E (GSDME) cleavage. Notably, lytic cell death caused the release of the damage-associated molecular patterns (DAMPs) heat shock protein-60 (HSP60) and S100A8/A9. This was accompanied by an impaired inflammatory response resulting in inhibited and delayed release of IL6 and TNF. Of note, increased cleaved caspase-3, higher levels of GSDME and altered expression of cell death-associated genes were found in alveolar macrophages of smoker subjects compared to non-smoking controls. Overall, our findings show that CSE sensitizes human macrophages to cell death by promoting pyroptotic and apoptotic pathways upon encountering LPS. We propose that while the delayed inflammatory response may result in ineffective defenses against infections, the observed cell death associated with DAMP release may contribute to establish chronic inflammation. CS exposure sensitizes human macrophages to pro-inflammatory cell death. Upon exposure to LPS, CS inhibits the TLR4/MyD88 inflammatory response, downregulating the pro-inflammatory genes TNF and IL6 and the anti-apoptotic gene CFLAR, known to counteract caspase-8 activity. CS enhances caspase-8 activation through TLR4/TRIF, with a partial involvement of RIPK1, resulting on the activation of caspase-1/GSDMD axis leading to increased cell permeability and DAMP release through gasdermin pores [19]. At later timepoints caspase-3 becomes strongly activated by caspase-8 triggering apoptotic events which are associated with mitochondrial membrane depolarization, gasdermin E cleavage and secondary necrosis with consequent massive DAMP release.

Do alternative tobacco products induce less adverse respiratory risk than cigarettes?

RATIONALE

Due to the relatively short existence of alternative tobacco products, gaps exist in our current understanding of their long-term respiratory health effects. We therefore undertook the first-ever side-by-side comparison of the impact of chronic inhalation of aerosols emitted from electronic cigarettes (EC) and heated tobacco products (HTP), and combustible cigarettes (CC) smoke.

OBJECTIVES

To evaluate the potential differential effects of alternative tobacco products on lung inflammatory responses and efficacy of vaccination in comparison to CC.

METHODS

Mice were exposed to emissions from EC, HTP, CC, or air for 8 weeks. BAL and lung tissue were analyzed for markers of inflammation, lung damage, and oxidative stress. Another group was exposed for 12 weeks and vaccinated and challenged with a bacterial respiratory infection. Antibody titers in BAL and sera and pulmonary bacterial clearance were assessed.

MAIN RESULTS

EC- and HTP-aerosols significantly augmented lung immune cell infiltrates equivalent to that achieved following CC-exposure. HTP and CC significantly increased neutrophil numbers compared to EC. All products augmented numbers of B cells, T cells, and pro-inflammatory IL17A+ T cells in the lungs. Decreased lung antioxidant activity and lung epithelial and endothelial damage was induced by all products. EC and HTP differentially augmented inflammatory cytokines/chemokines in the BAL. Generation of immunity following vaccination was impaired by EC and HTP but to a lesser extent than CC, with a CC > HTP > EC hierarchy of suppression of pulmonary bacterial clearance.

CONCLUSIONS

HTP and EC-aerosols induced a proinflammatory pulmonary microenvironment, lung damage, and suppressed efficacy of vaccination.

Not all vaping is the same: differential pulmonary effects of vaping cannabidiol versus nicotine

RATIONALE

Vaping has become a popular method of inhaling various psychoactive substances. While evaluating respiratory effects of vaping have primarily focused on nicotine-containing products, cannabidiol (CBD)-vaping is increasingly becoming popular. It currently remains unknown whether the health effects of vaping nicotine and cannabinoids are similar.

OBJECTIVES

This study compares side by side the pulmonary effects of acute inhalation of vaporised CBD versus nicotine.

METHODS

In vivo inhalation study in mice and in vitro cytotoxicity experiments with human cells were performed to assess the pulmonary damage-inducing effects of CBD or nicotine aerosols emitted from vaping devices.

MEASUREMENTS AND MAIN RESULTS

Pulmonary inflammation in mice was scored by histology, flow cytometry, and quantifying levels of proinflammatory cytokines and chemokines. Lung damage was assessed by histology, measurement of myeloperoxidase activity and neutrophil elastase levels in the bronchoalveolar lavage fluid and lung tissue. Lung epithelial/endothelial integrity was assessed by quantifying BAL protein levels, albumin leak and pulmonary FITC-dextran leak. Oxidative stress was determined by measuring the antioxidant potential in the BAL and lungs. The cytotoxic effects of CBD and nicotine aerosols on human neutrophils and human small airway epithelial cells were evaluated using in vitro air-liquid interface system. Inhalation of CBD aerosol resulted in greater inflammatory changes, more severe lung damage and higher oxidative stress compared with nicotine. CBD aerosol also showed higher toxicity to human cells compared with nicotine.

CONCLUSIONS

Vaping of CBD induces a potent inflammatory response and leads to more pathological changes associated with lung injury than vaping of nicotine.

A Proteomics Investigation of Cigarette Smoke Exposed Wistar Rats Revealed Improved Anti-Inflammatory Effects of the Cysteamine Nanoemulsions Delivered via Inhalation

Cigarette smoking is the major cause of chronic inflammatory diseases such as chronic obstructive pulmonary disease (COPD). It is paramount to develop pharmacological interventions and delivery strategies against the cigarette smoke (CS) associated oxidative stress in COPD. This study in Wistar rats examined cysteamine in nanoemulsions to counteract the CS distressed microenvironment. In vivo, 28 days of CS and 15 days of cysteamine nanoemulsions treatment starting on 29th day consisting of oral and inhalation routes were established in Wistar rats. In addition, we conducted inflammatory and epithelial-to-mesenchymal transition (EMT) studies in vitro in human bronchial epithelial cell lines (BEAS2B) using 5% CS extract. Inflammatory and anti-inflammatory markers, such as tumor necrosis factor-alpha (TNF-α), interleukin (IL)-6, IL-1β, IL-8, IL-10, and IL-13, have been quantified in bronchoalveolar lavage fluid (BALF) to evaluate the effects of the cysteamine nanoemulsions in normalizing the diseased condition. Histopathological analysis of the alveoli and the trachea showed the distorted, lung parenchyma and ciliated epithelial barrier, respectively. To obtain mechanistic insights into the CS COPD rat model, "shotgun" proteomics of the lung tissues have been carried out using high-resolution mass spectrometry wherein genes such as ABI1, PPP3CA, PSMA2, FBLN5, ACTG1, CSNK2A1, and ECM1 exhibited significant differences across all the groups. Pathway analysis showed autophagy, signaling by receptor tyrosine kinase, cytokine signaling in immune system, extracellular matrix organization, and hemostasis, as the major contributing pathways across all the studied groups. This work offers new preclinical findings on how cysteamine taken orally or inhaled can combat CS-induced oxidative stress.

Animal models and mechanisms of tobacco smoke-induced chronic obstructive pulmonary disease (COPD)

Chronic obstructive pulmonary disease (COPD) is the third leading cause of death worldwide, and its global health burden is increasing. COPD is characterized by emphysema, mucus hypersecretion, and persistent lung inflammation, and clinically by chronic airflow obstruction and symptoms of dyspnea, cough, and fatigue in patients. A cluster of pathologies including chronic bronchitis, emphysema, asthma, and cardiovascular disease in the form of hypertension and atherosclerosis variably coexist in COPD patients. Underlying causes for COPD include primarily tobacco use but may also be driven by exposure to air pollutants, biomass burning, and workplace related fumes and chemicals. While no single animal model might mimic all features of human COPD, a wide variety of published models have collectively helped to improve our understanding of disease processes involved in the genesis and persistence of COPD. In this review, the pathogenesis and associated risk factors of COPD are examined in different mammalian models of the disease. Each animal model included in this review is exclusively created by tobacco smoke (TS) exposure. As animal models continue to aid in defining the pathobiological mechanisms of and possible novel therapeutic interventions for COPD, the advantages and disadvantages of each animal model are discussed.

Association between inflammatory potential of diet and periodontitis disease risks: Results from a Korean population-based cohort study

AIM

To examine the association between a pro-inflammatory diet, estimated using the energy-adjusted dietary inflammatory index (E-DII), and the risk of periodontitis.

MATERIALS AND METHODS

Study subjects from the Korean Genome and Epidemiology Study Health Examinee (KoGES_HEXA) cohort were included for cross-sectional analysis (n = 168,378) using multivariate logistic regression and prospective analysis (n = 160,397) using Cox proportional hazard models respectively. DII and E-DII scores were calculated based on the intake reported on a validated semi-quantitative food frequency questionnaire (SQ-FFQ).

RESULTS

Cox proportional hazard models revealed a significantly increased risk of incident periodontitis in individuals consuming high E-DII (more pro-inflammatory) diets in the total population (HRquartile4vs1  = 1.29; 95% CI: 1.13-1.48; ptrend <.001) and in both men (HRquartile4vs1  = 1.36; 95% CI: 1.07-1.73; ptrend  = 0.02) and women (HRquartile4vs1  = 1.27; 95% CI: 1.08-1.50; ptrend  = .002). The association remained significant even after excluding cases diagnosed early in the follow-up. In the cross-sectional analysis, a significant association was observed between the E-DII score and the prevalence of periodontitis among all study subjects (ORquartile4vs1  = 1.17; 95% CI: 1.03-1.34; ptrend  = 0.01) and men (ORquartile4vs1  = 1.28; 95%CI: 1.01-1.63; ptrend <.001); however, the association did not reach statistical significance in women (ORquartile4vs1  = 1.13; 95% CI: 0.96-1.33; ptrend <.001).

CONCLUSIONS

Findings from the current study support the hypothesis that diets with high pro-inflammatory potential increase the risk of periodontitis.

Cigarette Smoke-Induced Respiratory Response: Insights into Cellular Processes and Biomarkers

Cigarette smoke (CS) poses a significant risk factor for respiratory, vascular, and organ diseases owing to its high content of harmful chemicals and reactive oxygen species (ROS). These substances are known to induce oxidative stress, inflammation, apoptosis, and senescence due to their exposure to environmental pollutants and the presence of oxidative enzymes. The lung is particularly susceptible to oxidative stress. Persistent oxidative stress caused by chronic exposure to CS can lead to respiratory diseases such as chronic obstructive pulmonary disease (COPD), pulmonary fibrosis (PF), and lung cancer. Avoiding exposure to environmental pollutants, like cigarette smoke and air pollution, can help mitigate oxidative stress. A comprehensive understanding of oxidative stress and its impact on the lungs requires future research. This includes identifying strategies for preventing and treating lung diseases as well as investigating the underlying mechanisms behind oxidative stress. Thus, this review aims to investigate the cellular processes induced by CS, specifically inflammation, apoptosis, senescence, and their associated biomarkers. Furthermore, this review will delve into the alveolar response provoked by CS, emphasizing the roles of potential therapeutic target markers and strategies in inflammation and oxidative stress.

The Contrasting Seasonality Patterns of Some Cancer-Types and Herpes Zoster Can Be Explained by a Binary Classification of Immunological Reactions

A binary classification of the pathogenic immune reactions as anti-inflammatory high-Treg reactions or pro-inflammatory low-Treg reactions explains both the relatively low incidence rate of several types of cancer, and the relatively high incidence rate of herpes zoster cases diagnosed in the summer compared to cases diagnosed in the winter (in regions with temperate climate). This binary model also elucidates the longer survival of cancer patients diagnosed during the summer compared to these diagnosed in the winter. The three key elements of this explanation are: (a) the effect of sunlight on Treg production; (b) the evolvement of cancer from a low-Treg condition at early stage, to a high-Treg condition at advanced stage, and (c) the evolvement of herpes zoster from a high-Treg condition at pre-exudative stage to a low-Treg condition at acute exudative stage. A significant proportion of indolent tumors at the time of diagnosis (>20%) is a prerequisite for a beneficial effect of sunlight on cancer incidence rate and prognosis. This prerequisite restricts the beneficial effect of diagnosis during summer to certain types of cancer. Clinical implication: the prognosis of early stage tumors may be improved by a course of corticosteroid (or other immunosuppressant) treatment.

NLRP3 inflammasome activation in cigarette smoke priming for Pseudomonas aeruginosa-induced acute lung injury

It is increasingly recognized that cigarette smoke (CS) exposure increases the incidence and severity of acute respiratory distress syndrome (ARDS) in critical ill humans and animals. However, the mechanism(s) is not well understood. This study aims to investigate mechanism underlying the priming effect of CS on Pseudomonas aeruginosa-triggered acute lung injury, by using pre-clinic animal models and genetically modified mice. We demonstrated that CS impaired P. aeruginosa-induced mitophagy flux, promoted p62 accumulation, and exacerbated P. aeruginosa-triggered mitochondrial damage and NLRP3 inflammasome activation in alveolar macrophages; an effect associated with increased acute lung injury and mortality. Pharmacological inhibition of caspase-1, a component of inflammasome, attenuated CS primed P. aeruginosa-triggered acute lung injury and improved animal survival. Global or myeloid-specific knockout of IL-1β, a downstream component of inflammasome activation, also attenuated CS primed P. aeruginosa-triggered acute lung injury. Our results suggest that NLRP3 inflammasome activation is an important mechanism for CS primed P. aeruginosa-triggered acute lung injury. (total words: 155).

Dung biomass smoke exposure impairs resolution of inflammatory responses to influenza infection

Epidemiological studies associate biomass smoke with an increased risk for respiratory infections in children and adults in the developing world, with 500,000 premature deaths each year attributed to biomass smoke-related acute respiratory infections including infections caused by respiratory viruses. Animal dung is a biomass fuel of particular concern because it generates more toxic compounds per amount burned than wood, and is a fuel of last resort for the poorest households. Currently, there is little biological evidence on the effects of dung biomass smoke exposure on immune responses to respiratory viral infections. Here, we investigated the impact of dung biomass exposure on respiratory infection using a mouse model of dung biomass smoke and cultured primary human small airway epithelial cells (SAECs). Mice infected with influenza A virus (IAV) after dung biomass smoke exposure had increased mortality, lung inflammation and virus mRNA levels, and suppressed expression of innate anti-viral mediators compared to air exposed mice. Importantly, there was still significant tissue inflammation 14 days after infection in dung biomass smoke-exposed mice even after inflammation had resolved in air-exposed mice. Dung biomass smoke exposure also suppressed the production of anti-viral cytokines and interferons in cultured SAECs treated with poly(I:C) or IAV. This study shows that dung biomass smoke exposure impairs the immune response to respiratory viruses and contributes to biomass smoke-related susceptibility to respiratory viral infections, likely due to a failure to resolve the inflammatory effects of biomass smoke exposure.

Crosstalk between gut microbiota and lung inflammation in murine toxicity models of respiratory exposure or co-exposure to carbon nanotube particles and cigarette smoke extract

Carbon nanotubes (CNTs) are emerging environmental and occupational toxicants known to induce lung immunotoxicity. While the underlying mechanisms are evolving, it is yet unknown whether inhaled CNTs would cause abnormalities in gut microbiota (dysbiosis), and if such microbiota alteration plays a role in the modulation of CNT-induced lung immunotoxicity. It is also unknown whether co-exposure to tobacco smoke will modulate CNT effects. We compared the effects of lung exposure to multi-wall CNT, cigarette smoke extract (CSE), and their combination (CNT + CSE) in a 4-week chronic toxicity mouse model. The exposures induced differential perturbations in gut microbiome as evidenced by altered microbial α- and β- diversity, indicating a lung-to-gut communication. The gut dysbiosis due to CNTs, unlike CSE, was characterized by an increase in Firmicutes/Bacteroidetes ratio typically associated with proinflammatory condition. Notably, while all three exposures reduced Proteobacteria, the CNT exposure and co-exposure induced appearance of Tenericutes and Cyanobacteria, respectively, implicating them as potential biomarkers of exposure. CNTs differentially induced certain lung proinflammatory mediators (TNF-α, IL-1β, CCL2, CXCL5) whereas CNTs and CSE commonly induced other mediators (CXCL1 and TGF-β). The co-exposure showed either a component-dominant effect or a summative effect for both dysbiosis and lung inflammation. Depletion of gut microbiota attenuated both the differentially-induced and commonly-induced (TGF-β) lung inflammatory mediators as well as granulomas implying gut-to-lung communication and a modulatory role of gut dysbiosis. Taken together, the results demonstrated gut dysbiosis as a systemic effect of inhaled CNTs and provided the first evidence of a bidirectional gut-lung crosstalk modulating CNT lung immunotoxicity.

Predicting the pulmonary effects of long-term e-cigarette use: are the clouds clearing?

Commercially available since 2007, e-cigarettes are a popular electronic delivery device of ever-growing complexity. Given their increasing use by ex-smokers, smokers and never-smokers, it is important to evaluate evidence of their potential pulmonary effects and predict effects of long-term use, since there has been insufficient time to study a chronic user cohort. It is crucial to evaluate indicators of harm seen in cigarette use, and those potentially unique to e-cigarette exposure. Evaluation must also account for the vast variation in e-cigarette devices (now including at least five generations of devices) and exposure methods used in vivo and in vitroThus far, short-term use cohort studies, combined with in vivo and in vitro models, have been used to probe for the effects of e-cigarette exposure. The effects and mechanisms identified, including dysregulated inflammation and decreased pathogen resistance, show concerning overlaps with the established effects of cigarette smoke exposure. Additionally, research has identified a signature of dysregulated lipid processing, which is unique to e-cigarette exposure.This review will evaluate the evidence of pulmonary effects of, and driving mechanisms behind, e-cigarette exposure, which have been highlighted in emerging literature, and highlight the gaps in current knowledge. Such a summary allows understanding of the ongoing debate into e-cigarette regulation, as well as prediction and potential mitigation of future problems surrounding e-cigarette use.

Low Eosinophil Phenotype Predicts Noninvasive Mechanical Ventilation Use in Patients with Hospitalized Exacerbations of COPD

Rationale

Objective

Methods

Results

Conclusion

The additional value of lung cancer screening program in identifying unrecognized diseases

Background

A systematic examination of low-dose CT (LDCT) scan, beside lung nodules, may disclose the presence of undiagnosed diseases, improving the efficacy and the cost/efficacy of these programs. The study was aimed at evaluating the association between LDCT scan findings and non-oncologic and oncologic diseases.

Methods

The LDCT scan of participants to the “Un Respiro per la vita”^® lung cancer screening program were checked and abnormal findings, beside lung nodules, recorded. First admission to the acute care because of cardiovascular (CD), respiratory (RD) and oncological diseases (OD) in the following three years were retrieved. The association of LDCT scan abnormal findings with CD, RD and OD was assessed through univariable and multivariable logistic regression models.

Results

Mean age of 746 participants was 62 years (SD:5), 62% were male. 11 (1.5%) received a diagnosis of lung cancer. 16.1% participants were admitted to the acute care in the following three years: 8.6% for CD, 4.3% for RD and 5.2% for OD. Valve calcification (OR 2.02, p:0.02) and mucus plugs (OR 3.37, p:0.04) were positively associated with CD, while sub-pleural fibrosis had a protective role (OR 0.47, p:0.01). Lung nodules > 8 mm (OR 5.54, p: < 0.01), tracheal deviation (OR 6.04, p:0.01) and mucus plugs (OR 4.00, p:0.04) were positively associated with OD admissions. Centrilobular emphysema OR for RD admissions was 1.97 (p:0.06).

Conclusions

The observed association between selected LDCT findings and ensuing CD, RD and OD suggests that the information potential of LCDT goes beyond the screening of lung cancer.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12890-022-01826-1.

Effects of Maxingloushi decoction on immune inflammation and programmed death markers in mice with chronic obstructive pulmonary disease

BACKGROUND

To investigate effects of Maxingloushi decoction on lung inflammation and programmed death markers (programmed death-1 [PD-1], programmed death-ligand 1 [PD-L1]) in the lung tissue, peripheral blood, and bronchoalveolar lavage fluid (BLF) in a mouse model of chronic obstructive pulmonary disease (COPD).

METHODS

Thirty-six mature male BALB/C mice were randomly divided into normal group (group A, n=6), COPD model group (group B, n=10), Maxingloushi decoction + COPD group (group C, n=10), and PD-1 inhibitor + COPD group (group D, n=10). The COPD model was established by smoke inhalation combined with lipopolysaccharide (LPS). Levels of PD-1 and PD-L1 in plasma and BLF were measured by enzyme-linked immunosorbent assay (ELISA). Histopathological techniques were used to semi-quantitatively analyze the immuno-fluorescence optical density (IOD) value of the lung tissue.

RESULTS

In plasma and BLF, the expression of PD-1 in the group B was higher than that in the group A, and the expression of PD-L1 was lower than that in the group A. The expression of PD-1 and PD-L1 in the lung tissue was normalized in the group C in comparison with the group B (P<0.05) and the group D (P<0.05), and inflammatory cell infiltration in the lung tissue was also improved.

CONCLUSIONS

These findings reveal that COPD causes an immune imbalance in the peripheral blood and lung tissue, and that both Maxingloushi decoction and PD-1 inhibitor treatment can mitigate lung inflammation in COPD by reducing PD-1 expression and increasing PD-L1 expression. The treatment effect of Maxingloushi decoction may be superior to that of PD-1 inhibitor.

Cumulative Occupational Exposures and Lung-Function Decline in Two Large General-Population Cohorts

Rationale: Few longitudinal studies have assessed the relationship between occupational exposures and lung-function decline in the general population with a sufficiently long follow-up.Objectives: To examine the potential association in two large cohorts: the ECRHS (European Community Respiratory Health Survey) and the SAPALDIA (Swiss Cohort Study on Air Pollution and Lung and Heart Diseases in Adults).Methods: General-population samples of individuals aged 18 to 62 were randomly selected in 1991-1993 and followed up approximately 10 and 20 years later. Spirometry (without bronchodilation) was performed at each visit. Coded complete job histories during follow-up visits were linked to a job-exposure matrix, generating cumulative exposure estimates for 12 occupational exposures. Forced expiratory volume in 1 second (FEV₁) and forced vital capacity (FVC) were jointly modeled in linear mixed-effects models, fitted in a Bayesian framework, taking into account age and smoking.Results: A total of 40,024 lung-function measurements from 17,833 study participants were analyzed. We found accelerated declines in FEV₁ and the FEV₁/FVC ratio for exposure to biological dust, mineral dust, and metals (FEV₁ = -15.1 ml, -14.4 ml, and -18.7 ml, respectively; and FEV₁/FVC ratio = -0.52%, -0.43%, and -0.36%, respectively; per 25 intensity-years of exposure). These declines were comparable in magnitude with those associated with long-term smoking. No effect modification by sex or smoking status was identified. Findings were similar between the ECRHS and the SAPALDIA cohorts.Conclusions: Our results greatly strengthen the evidence base implicating occupation, independent of smoking, as a risk factor for lung-function decline. This highlights the need to prevent or control these exposures in the workplace.

Acute Effects of Heated Tobacco Product (IQOS) Aerosol Inhalation on Lung Tissue Damage and Inflammatory Changes in the Lungs

INTRODUCTION

Emerging heated tobacco products (HTPs) were designed to reduce exposure to toxicants from cigarette smoke (CS) by avoiding burning tobacco and instead heating tobacco. We studied the effects of short-term inhalation of aerosols emitted from HTP called IQOS, on lung damage and immune-cell recruitment to the lungs in mice.

METHODS

Numerous markers of lung damage and inflammation including albumin and lung immune-cell infiltrates, proinflammatory cytokines, and chemokines were quantified in lungs and bronchoalveolar (BAL) fluid from IQOS, CS, or air-exposed (negative control) mice.

RESULTS

Importantly, as a surrogate marker of lung epithelial-cell damage, we detected significantly increased levels of albumin in the BAL fluid of both HTP- and CS-exposed mice compared with negative controls. Total numbers of leukocytes infiltrating the lungs were equivalent following both IQOS aerosols and CS inhalation and significantly increased compared with air-exposed controls. We also observed significantly increased numbers of CD4+IL-17A+ T cells, a marker of a T-cell immune response, in both groups compared with air controls; however, numbers were the highest following CS exposure. Finally, the numbers of CD4+RORγt+ T cells, an inflammatory T-cell subtype expressing the transcription factor that is essential for promoting differentiation into proinflammatory Th17 cells, were significantly augmented in both groups compared with air-exposed controls. Levels of several cytokines in BAL were significantly elevated, reflecting a proinflammatory milieu.

CONCLUSIONS

Our study demonstrates that short-term inhalation of aerosols from IQOS generates damage and proinflammatory changes in the lung that are substantially similar to that elicited by CS exposure.

IMPLICATIONS

Exposure of mice to IQOS, one of the candidate modified-risk tobacco products, induces inflammatory immune-cell accumulation in the lungs and augments the levels of proinflammatory cytokines and chemokines in the BAL fluid. Such an exacerbated pulmonary proinflammatory microenvironment is associated with lung epithelial-cell damage in IQOS-exposed mice, suggesting a potential association with the impairment of lung function.

[Effect of intensity of smoking intoxication on severity parameters of acute exacerbations of chronic obstructive pulmonary disease treated in a hospital milieu]

Introduction

le tabagisme constitue le principal facteur de risque de la broncho-pneumopathie chronique obstructive (BPCO). Le cours évolutif de cette maladie est caractérisé par la survenue des exacerbations aiguës (EA). L'objectif de notre travail est d'évaluer l´impact de l´intensité de l´intoxication tabagique (en paquets-années (PA)) sur les différents paramètres de sévérité des EA des patients BPCO non sevrés hospitalisés.

Méthodes

c´est une étude rétrospective, monocentrique, portant sur 685 patients porteurs de BPCO, tabagiques non sevrés ayant été hospitalisés au moins une fois pour une EA entre 1990 et 2017. Nous avons défini 2 groupes de patients (G1: < 30PA, et G2: ≥ 30PA). Nous avons comparé les différents paramètres de sévérité des EA BPCO entre les deux groupes.

Résultats

l´âge moyen de nos patients était de 66 ans. Il n'y avait pas de différence significative entre les deux groupes concernant l´importance du syndrome inflammatoire biologique, la durée de l´hospitalisation et celle de l´antibiothérapie. Le G2 était caractérisé par une PaO2 plus basse au cours des EA (G1: 63,5, G2: 59,3, p: 0,007), avec plus d'hospitalisation en réanimation (p < 0,001), plus de recours à la ventilation non invasive (p: < 0.001) et à la ventilation invasive (p: 0,008). Le G2 avait plus d'EA/an (G1: 2,06, G2: 2,72/patient/an, p: 0,001) avec un délai moyen de survenue d'EA sévère plus court (p: 0,038).

Conclusion

l´intensité de l´intoxication tabagique a un impact négatif sur plusieurs paramètres de sévérité des EA sévères de BPCO. D´où l´intérêt de sevrage tabagique pour prévenir la maladie et ses complications.

The Effect of Residential Environment on Respiratory Diseases and Pulmonary Function in Children from a Community in Jilin Province of China

Purpose

Respiratory disease is a major and increasingly global epidemic that has a great impact on humans, especially children. The purpose of this study was to identify environmental risk factors for respiratory diseases and pulmonary function in children.

Patients and Methods

A population-based, cross-sectional survey of respiratory diseases and environmental risk factors was conducted in Jilin Province, China. Complete questionnaire information was available for 2419 children, while adequate pulmonary function data were available for a subgroup of 627 children.

Results

Our study found that environmental risk factors for respiratory health in children were mainly concentrated indoors. After adjusting for demographic factors, insecticide exposure and passive smoking were risk factors for respiratory disease and industrial pollutant sources, insecticide exposure and the use of a fume exhauster may be independent risk factors for recurrent respiratory infections. The main fuel for cooking in the winter and passive smoking were the main influencing factors of pulmonary function indicators.

Conclusion

The primary risk factors differ in different respiratory diseases. Passive smoking remains a critical adverse factor for respiratory illness and pulmonary function in children, and it is important to reduce children’s exposure to passive smoking to increase pulmonary health. Insecticide exposure may be a neglected environmental risk factor, and further investigations are still needed to explore the relationship and mechanisms between insecticide exposure and children’s respiratory health.

Particulate air pollution and respiratory Haemophilus influenzae infection in Mianyang, southwest China

Particulate air pollution is correlated with many respiratory diseases. However, few studies have focused on the relationship between air particulate exposure and respiratory Heamophilus influenzae infection. Therefore, we detected respiratory Heamophilus influenzae infection by bacterial culture of sputum of patients, and we collected particulate air pollution data (including PM2.5 and PM10) from a national real-time urban air quality platform to analyze the relationship between particulate air pollution and respiratory Heamophilus influenzae infection. The mean concentrations of PM2.5 and PM10 were 37.58 μg/m3 and 58.44 μg/m3, respectively, showing particulate air pollution remains a severe issue in Mianyang. A total of 828 strains of Heamophilus influenzae were detected in sputum by bacterial culture. Multiple correspondence analysis suggested the heaviest particulate air pollution and the highest Heamophilus influenzae infection rates were all in winter, while the lowest particulate air pollution and the lowest Heamophilus influenzae infection rates were all in summer. In a single-pollutant model, each elevation of 10 μg/m3 of PM2.5, PM10, and PM2.5/10 (combined exposure level) increased the risk of respiratory Heamophilus influenzae infection by 34%, 23%, and 29%, respectively. Additionally, in the multiple-pollutant model, only PM2.5 was significantly associated with respiratory Heamophilus influenzae infection (B, 0.46; 95% confidence interval, 0.05-0.87), showing PM2.5 is an independent risk factor for respiratory Heamophilus influenzae infection. In summary, this study highlights air particulate exposure could increase the risk of respiratory Heamophilus influenzae infection, implying that stronger measures need to be taken to protect against respiratory infection induced by particulate air pollution.

AT-RvD1 Mitigates Secondhand Smoke-Exacerbated Pulmonary Inflammation and Restores Secondhand Smoke-Suppressed Antibacterial Immunity

Cigarette smoke is a potent proinflammatory trigger contributing to acute lung injury and the development of chronic lung diseases via mechanisms that include the impairment of inflammation resolution. We have previously demonstrated that secondhand smoke (SHS) exposure exacerbates bacterial infection-induced pulmonary inflammation and suppresses immune responses. It is now recognized that resolution of inflammation is a bioactive process mediated by lipid-derived specialized proresolving mediators that counterregulate proinflammatory signaling and promote resolution pathways. We therefore hypothesized that proresolving mediators could reduce the burden of inflammation due to chronic lung infection following SHS exposure and restore normal immune responses to respiratory pathogens. To address this question, we exposed mice to SHS followed by chronic infection with nontypeable Haemophilus influenzae (NTHI). Some groups of mice were treated with aspirin-triggered resolvin D1 (AT-RvD1) during the latter half of the smoke exposure period or during a period of smoking cessation and before infection. Treatment with AT-RvD1 markedly reduced the recruitment of neutrophils, macrophages, and T cells in lung tissue and bronchoalveolar lavage and levels of proinflammatory cytokines in the bronchoalveolar lavage. Additionally, treatment with AT-RvD1 improved Ab titers against the NTHI outer membrane lipoprotein Ag P6 following infection. Furthermore, treatment with AT-RvD1 prior to classically adjuvanted immunization with P6 increased Ag-specific Ab titers, resulting in rapid clearance of NTHI from the lungs after acute challenge. Collectively, we have demonstrated that AT-RvD1 potently reverses the detrimental effects of SHS on pulmonary inflammation and immunity and thus could be beneficial in reducing lung injury associated with smoke exposure and infection.

The Potential for Phospholipids in the Treatment of Airway Inflammation: An Unexplored Solution

Asthma, chronic obstructive pulmonary disease (COPD), and cystic fibrosis (CF) are major inflammatory respiratory diseases. Current mainstay therapy for asthma, and chronic obstructive pulmonary disease are corticosteroids, which have well-established side effect profiles. Phospholipids (PLs) are ubiquitous, diverse compounds with varying functions such as their structural role incell membrane, energy storage, and cell signaling.Recent advances in understanding PLs role as inflammatory mediators in the body as well as their widespread long-standing use as carrier molecules in drug delivery demonstrate the potential application of phospholipids in modulating inflammatory conditions. This review briefly explains the main mechanisms of inflammation in chronic respiratory diseases, currentanti-inflammatory treatments and areas of unmet need. The structural features, roles of endogenous and exogenous phospholipids, including their use as pharmaceutical excipients are reviewed. Current research on the immunomodulatory properties of PLs and their potentialapplication in inflammatory diseasesis the major section of this review. Considering the roles of PLs as inflammatory mediators and their safety profile established in pharmaceutical formulations, these small molecules demonstrate great potential as candidates in respiratory inflammation. Future studies need to focus on the immunomodulatory properties and the underlying mechanisms of phospholipids in respiratory inflammatory diseases.

Inhalation exposure by cigarette smoke: Effects on the progression of bleomycin- and lipopolysaccharide-induced lung injuries in rat models

The toxic substances of cigarette smoke (CS) induce inflammatory responses in the lung by recruiting inflammatory cells. In this study, we investigated the effects of CS on the progression of lung disease in bleomycin (BLM) and lipopolysaccharide (LPS)-induced lung injury rat models. Briefly, rats were exposed to CS via inhalation (nose-only) for 28 consecutive days, for 4 h per day. Using an automatic video instillator, rats were administered a single dose of 2.5 mg/kg BLM (day 1) or 0.5 mg/kg LPS (day 26), prepared in 50 μL phosphate-buffered saline (PBS) solution. Examination of the bronchoalveolar lavage fluid (BALF) revealed that the number of neutrophils increased in a concentration-dependent manner of CS. Exposure to CS also enhanced the expression of cytokines, i.e., CCL2 (MCP-1), CCL3 (MIP-1α), CXCL2 (CINC3), CXCL10 (IP-10), TNF-α, IFN-γ, IL-2, IL-4 in the BALF of the vehicle (VC) and BLM groups in a concentration-dependent manner. In particular, the expressions of CCL2, CXCL10 and TNF-α were remarkably upregulated in the BLM + CS 300 treatment as compared to VC, while there were no differences in these cytokine levels in the serum following CS exposure. Exposure to CS resulted in compacted alveolar spaces and macrophage aggregation in the lung tissues following BLM and LPS treatments. Compared to VC, pulmonary fibrosis and chronic inflammation of bronchioloalveoli were observed in the BLM + CS treatment and inflammatory cell infiltration of bronchioloalveoli was observed in the LPS + CS treatment in a concentration-dependent manner by CS. The expression levels of CCL2 and IFN-γ in the lung tissues were increased similar to the levels obtained in BALF, in a concentration-dependent manner by CS. Taken together, these results indicate that repeated exposure to CS may exacerbate the lung injury initially caused by BLM and LPS.

Heterogeneity of Paucigranulocytic Asthma: A Prospective Cohort Study with Hierarchical Cluster Analysis

BACKGROUND

Asthma, a heterogeneous disease, can be divided into 4 inflammatory phenotypes using induced sputum cell counts-eosinophilic asthma (EA), neutrophilic asthma (NA), mixed granulocytic asthma, and paucigranulocytic asthma (PGA). Although research has focused on EA and NA, there is little known about PGA.

OBJECTIVE

To study the heterogeneity of PGA and identify possible PGA clusters to guide clinical treatment.

METHODS

Patients with PGA were grouped by hierarchical cluster analysis and enrolled into a prospective cohort study to validate the clusters, relative to future risk of asthma exacerbations in a real-world setting. Clusters were validated by tree analysis in a separate population. Finally, we explored PGA stability.

RESULTS

Cluster analysis of 145 patients with PGA identified 3 clusters: cluster 1 (n = 110, 75.9%) was "mild PGA," cluster 2 (n = 20, 13.8%) was "PGA with psychological dysfunction and rhinoconjunctivitis and other allergic diseases," and cluster 3 (n = 15, 10.3%) was "smoking-associated PGA." Cluster 3 had significantly increased risk of severe exacerbation (relative risk [RR] = 6.43, P = .01), emergency visit (RR = 8.61, P = .03), and hospitalization (RR = 12.94, P < .01). Results of the cluster analysis were successfully validated in an independent PGA population classified using decision tree analysis. Although PGA can transform into or develop from other phenotypes, 70% were stable over time.

CONCLUSIONS

Among 3 identified PGA clusters, cluster 3 had a higher risk of severe exacerbation. PGA heterogeneity indicates the requirement of novel targeted interventions.

Th17 cells are involved in mouse chronic obstructive pulmonary disease complicated with invasive pulmonary aspergillosis

BACKGROUND

The incidence of chronic obstructive pulmonary disease (COPD) complicated with invasive pulmonary aspergillosis (IPA) has increased in the last two decades. The mechanism underpinning susceptibility to and high mortality of COPD complicated with IPA is unclear, and the role of T helper cells 17 (Th17 cells) in the compound disease remains unknown. Therefore, this study aimed to assess the function of Th17 cells in COPD combined with IPA.

METHODS

COPD, IPA, and COPD+IPA mouse models were established in male wild type C57/BL6 mice. The amounts of Th17 cells and retinoic acid-related orphan receptors γt (RORγt) were tested by flow cytometry. Then, serum interleukin (IL)-17 and IL-23 levels were detected by enzyme-linked immunosorbent assay (ELISA) in the control, COPD, IPA and COPD+IPA groups. In addition, COPD+IPA was induced in IL-17 knockout (KO) mice, for determining the role of Th17 cells in COPD+IPA.

RESULTS

Compared with the COPD group, the COPD+IPA group showed higher amounts of blood RORγt ([35.09 ± 16.12]% vs. [17.92 ± 4.91]%, P = 0.02) and serum IL-17 (17.96 ± 9.59 pg/mL vs. 8.05 ± 4.44 pg/mL, P = 0.02), but blood ([5.18 ± 1.09]% vs. [4.15 ± 0.87]%, P = 0.28) and lung levels of Th17 cells ([1.98 ± 0.83]% vs. [2.03 ± 0.98]%, P = 0.91), lung levels of RORγt ([9.58 ± 6.93]% vs. [9.63 ± 5.98]%, P = 0.49) and serum IL-23 (51.55 ± 27.82 pg/mL vs. 68.70 ± 15.20 pg/mL, P = 0.15) showed no significant differences. Compared with the IPA group, the COPD+IPA group displayed lower amounts of blood ([5.18 ± 1.09]% vs. [9.21 ± 3.56]%, P = 0.01) and lung Th17 cells ([1.98 ± 0.83]% vs. [6.29 ± 1.11]%, P = 0.01) and serum IL-23 (51.55 ± 27.82 pg/mL vs. 154.90 ± 64.60 pg/mL, P = 0.01) and IL-17 (17.96 ± 9.59 pg/mL vs. 39.81 ± 22.37 pg/mL, P = 0.02), while comparable blood ([35.09 ± 16.12]% vs. [29.86 ± 15.42]%, P = 0.25) and lung levels of RORγt ([9.58 ± 6.93]% vs. [15.10 ± 2.95]%, P = 0.18) were found in these two groups. Finally, Aspergillus load in IL-17 KO COPD+IPA mice was almost 2 times that of COPD+IPA mice (1,851,687.69 ± 944,480.43 vs. 892,958.10 ± 686,808.80, t = 2.32, P = 0.02).

CONCLUSION

These findings indicate that Th17 cells might be involved in the pathogenesis of COPD combined with IPA, with IL-17 likely playing an antifungal role.

Proteomics analysis of lung reveals inflammation and cell death induced by atmospheric H2S exposure in pig

Hydrogen sulfide (H₂S) is a popular toxic environmental gas and industrial pollutant, which can be harmful to multiple organ systems of both human and livestock, especially to the respiratory system. However, the injury mechanism of H₂S exposure to lung remains poorly understood. In this study, pig lung was selected as a H₂S exposure model for the first time. We first examined the histological damage and the mRNA expression of pro-inflammatory genes of lung in pigs exposed to H₂S. Histopathology change and increased mRNA level of pro-inflammatory cytokines demonstrated that H₂S exposure indeed induced inflammatory injury in the porcine lung. We then performed TMT-based quantitative proteomics analysis to probe the injury molecular mechanism. The proteomics results showed that 526 proteins have significant changes in abundance between control and H₂S treated swine. Further validation analysis of some H₂S responsive proteins using both Real-time quantitative PCR and western blotting demonstrated that proteomics data are reliable. KEGG pathway analysis revealed that these proteins were involved in antigen processing and presentation, complement and coagulation cascade, IL-17 signaling pathway, ferroptosis and necroptosis. Our data suggest that H₂S exposure induced immune suppression, inflammatory response and cell death. These findings provide a new insight into the complexity mechanisms of H₂S induced lung injury, and offer therapeutic potential as drug targets with a view towards curing the intoxication caused by H₂S.

Specialized Proresolving Mediators Overcome Immune Suppression Induced by Exposure to Secondhand Smoke

Tobacco smoke exposure is associated with multiple diseases including, respiratory diseases like asthma and chronic obstructive pulmonary disease. Tobacco smoke is a potent inflammatory trigger and is immunosuppressive, contributing to increased susceptibility to pulmonary infections in smokers, ex-smokers, and vulnerable populations exposed to secondhand smoke. Tobacco smoke exposure also reduces vaccine efficacy. Therefore, mitigating the immunosuppressive effects of chronic smoke exposure and improving the efficacy of vaccinations in individuals exposed to tobacco smoke, is a critical unmet clinical problem. We hypothesized that specialized proresolving mediators (SPMs), a class of immune regulators promoting resolution of inflammation, without being immunosuppressive, and enhancing B cell Ab responses, could reverse the immunosuppressive effects resulting from tobacco smoke exposure. We exposed mice to secondhand smoke for 8 wk, followed by a period of smoke exposure cessation, and the mice were immunized with the P6 lipoprotein from nontypeable Haemophilus influenzae, using 17-HDHA and aspirin-triggered-resolvin D1 (AT-RvD1) as adjuvants. 17-HDHA and AT-RvD1 used as adjuvants resulted in elevated serum and bronchoalveolar lavage levels of anti-P6-specific IgG and IgA that were protective, with immunized mice exhibiting more rapid bacterial clearance upon challenge, reduced pulmonary immune cell infiltrates, reduced production of proinflammatory cytokines, and less lung-epithelial cell damage. Furthermore, the treatment of mice with AT-RvD1 during a period of smoke-cessation further enhanced the efficacy of SPM-adjuvanted P6 vaccination. Overall, SPMs show promise as novel vaccine adjuvants with the ability to overcome the tobacco smoke-induced immunosuppressive effects.

Disruption of Physiological Rhythms Persist Following Cessation of Cigarette Smoke Exposure in Mice

Background

Physiological rhythms in mammals are essential for maintaining health, whereas disruptions may cause or exacerbate disease pathogenesis. As such, our objective was to characterize how cigarette smoke exposure affects physiological rhythms of otherwise healthy mice using telemetry and cosinor analysis.

Methods

Female BALB/c mice were implanted with telemetry devices to measure body temperature, heart rate, systolic blood pressure (SBP), and activity. Following baseline measurements, mice were exposed to cigarette smoke for approximately 50 min twice daily during weekdays over 24 weeks. Physiological parameters were recorded after 1, 4, 8, and 24 weeks of exposure or after 4 weeks cessation following 4 weeks of cigarette smoke exposure.

Results

Acute cigarette smoke exposure resulted in anapyrexia, and bradycardia, with divergent effects on SBP. Long term, cigarette smoke exposure disrupted physiological rhythms after just 1 week, which persisted across 24 weeks of exposure (as shown by mixed effects on mesor, amplitude, acrophase, and goodness-of-fit using cosinor analysis). Four weeks of cessation was insufficient to allow full recovery of rhythms.

Conclusion

Our characterization of the pathophysiology of cigarette smoke exposure on physiological rhythms of mice suggests that rhythm disruption may precede and contribute to disease pathogenesis. These findings provide a clear rationale and guide for the future use of chronotherapeutics.

Changes in children's asthma prevalence over two decades in Lanzhou: effects of socioeconomic, parental and household factors

Background

The prevalence of childhood asthma may have changed with rapid economic development. This study aims to ascertain potential changes in asthma prevalence in relation to changes in socioeconomic, parental and household factors, based on a comparison between two periods spanning over 20 years in Lanzhou, a large northwestern city of China.

Methods

Cross-sectional studies using the same protocols were performed in Lanzhou, China in 1994–1995 (Period I) and in 2017 (Period II). Children of 6–12 years old from elementary schools were selected by a multistage sampling method. Information on the presence of asthma and asthma-related symptoms of children, socioeconomic status, feeding methods, parental illness and behavior patterns, as well as household characteristics, were collected through a questionnaire survey. Logistic regression models were used to estimate odds ratios of asthma prevalence with regard to socioeconomic, parental and household factors, respectively.

Results

Significant prevalence reductions were observed for paternal smoking, household coal use, and parental asthma, while the prevalence increased significantly for children sleeping in their own rooms or own beds, ventilation use during cooking, and parental occupation and education level after 22 years. In children, the prevalence of ever-diagnosed asthma decreased from 3.2% in period I to 1.5% in Period II (P<0.001); the prevalence of wheeze also decreased from 15.4% to 9.3% (P<0.001). Passive smoking (OR =1.531, 95% CI: 1.032–2.270) and poor household ventilation (OR =1.709, 95% CI: 1.208–2.416) were significantly associated with an increased prevalence of wheeze in Period I, whereas household mold (OR =2.112, 95% CI: 1.203–3.811) was significantly associated with prevalence of wheeze. Parental asthma history was associated with increased prevalence of asthma and asthma-related symptoms. Breastfeeding was significantly associated with reduced risk of asthma in period II children.

Conclusions

The prevalence of asthma and that of asthma-related symptoms were lower in 2017 than in 1994–1995 in school children living in Lanzhou. In 2017 with increased urbanization and industrialization, breastfeeding became a significant protective factor and household mold was a significant risk factor for asthma diagnosis and asthma-related symptoms. Promoting breastfeeding and household mold control is recommended to reduce the risk of childhood asthma in contemporary Lanzhou.

Evaluation of waterpipe smoke toxicity in C57BL/6 mice model

Waterpipe smoking is a popular pastime worldwide with statistics pointing to an alarming increase in consumption. In the current paper, the evaluation of sub-chronic waterpipe smoke exposure was undertaken using C57BL/6 female mice using a dynamic exposure setting to emulate smoke exposure. Mice were daily subjected to either one (single exposure, SE) or two sessions (double exposure, DE) of waterpipe-generated smoke (two-apple flavor) for a period of two months. Although lungs histopathological examination pointed to a minor inflammation in smoke-exposed mice compared to control air-exposed (CON) group, the lung weights of the waterpipe-exposed mice were significantly higher (+72% in SE and +39% in DE) (p < 0.01) when compared to CON group. Moreover, changes in the protein expression of several proteins such as iNOS and JNK were noted in the lungs of smoke-exposed mice. However, no changes in p38 and EGFR protein levels were noted between the three groups of mice. Our results mainly showed a significant increase in urea serum levels (+28%) in SE mice along with renal pathological damage in both SE and DE mice compared to CON. Additionally, severe significant DNA damages (p < 0.05) were reported in the lungs, kidneys, bone marrow and liver of waterpipe-exposed animals, using MTS and COMET assays. These findings highlighted the significant risks posed by sub-chronic waterpipe smoke exposure in the selected animal model and the pressing need for future better management of waterpipe indoor consumption.

"High Treg" Inflammations Promote (Most) Non-Hematologic Cancers While "Low Treg" Inflammations Promote Lymphoid Cancers

In an earlier publication, a binary classification of chronic diseases has been proposed. Chronic diseases were classified as “high Treg” or “low Treg” diseases depending on whether the pro-inflammatory or the anti-inflammatory arms of the immune response are deficient. The present work uses this model to analyze the interplay between cancer and the immune system, based on published literature. The work leans upon the etiology of alcohol and tobacco-related malignancies. The main conclusions are: triggers of specific “high Treg” immune reaction promote most non-hematologic cancers, whereas triggers of “low Treg” immune reaction promote lymphomas. The opposite is also true: triggers of specific “high Treg” immune reaction suppress lymphoma, whereas triggers of “low Treg” immune reaction suppress non-hematologic cancers. Both lymphoma and autoimmune diseases are “low Treg” conditions. For this reason, both are promoted by the same panel of “low Treg” bacteria and parasites and are inhibited by “high Treg” triggers. For example, alcohol consumption, a “high Treg” trigger, protects against lymphoma and autoimmune hypothyroidism. In addition, the same immune-modulatory drugs are effective in the treatment of both lymphoma and autoimmune diseases. Like other cancers, lymphoma transforms from a “low Treg” type at early stage of the disease into a “high Treg” type at advanced stages. However, lymphoma is distinguished from most other cancers by the length of time it dwells at an indolent “low Treg” state (many years) before lymphoma cells sensitivity to transforming growth factor-beta is impaired. This impairment stimulates the switch from “low Treg” into “high Treg” response and results in immune escape. The application of this analysis to the pharmacological activity of checkpoint inhibitors forecasts that checkpoint inhibitors would not be effective in low-grade, indolent lymphomas. As of now, checkpoint inhibitors are approved for the treatment of advanced lymphoma only.

Studying Effects of Cigarette Smoke on Pseudomonas Infection in Lung Epithelial Cells

Cigarette smoking is the major etiological cause for lung emphysema and chronic obstructive pulmonary disease (COPD). Cigarette smoking also promotes susceptibility to bacterial infections in the respiratory system. However, the effects of cigarette smoking on bacterial infections in human lung epithelial cells have yet to be thoroughly studied. Described here is a detailed protocol for the preparation of cigarette smoking extracts (CSE), treatment of human lung epithelial cells with CSE, and bacterial infection and infection determination. CSE was prepared with a conventional method. Lung epithelial cells were treated with 4% CSE for 3 h. CSE-treated cells were, then, infected with Pseudomonas at a multiplicity of infection (MOI) of 10. Bacterial loads of the cells were determined by three different methods. The results showed that CSE increased Pseudomonas load in lung epithelial cells. This protocol, therefore, provides a simple and reproducible approach to study the effect of cigarette smoke on bacterial infections in lung epithelial cells.

Trichostatin A alleviated ovarian tissue damage caused by cigarette smoke exposure

Cigarette smoke (CS) has a negative impact on women's health and fertility. Studies have shown that histone deacetylases 1 and 2 (HDAC1/2) were involved in oocyte development. However, the roles of HDAC1/2 in ovarian toxicity caused by CS exposure and the therapeutic potential of trichostatin A (TSA, a HDAC inhibitor) for ovarian tissue damage have not been investigated. In this study, Female C57BL/6 mice were exposed to CS from six cigarettes mixed with indoor air for 120 min (one cigarette for 20 min) using a whole-body mainstream smoke exposure system twice daily for 30 days. TSA (0.6 mg/kg body weight) was injected intraperitoneally into mice in the Control + TSA group and CS + TSA group every two days for 30 days. We found that exposure to CS resulted in ovarian tissue damage and HDAC1/2 over-expression. TSA alleviated the structural changes of ovarian tissue induced by smoking and prevented the activation of HDAC1/2. Exposure to CS caused autophagy inhibition and pyroptosis activation. TSA treatment restored the expression of autophagy-associated proteins and decreased the levels of pyroptosis-related proteins induced by CS exposure. The TSA effect may be mediated by inhibition of HDAC1/2 involved in autophagy and pyroptosis process.

The Role of Interleukin 1β in the Pathogenesis of Lung Cancer

Introduction

Chronic inflammation is associated with an increased risk of several diseases, including cancer. A complex tumor microenvironment created and maintained by a range of cell types promotes tumor growth, angiogenesis, and metastasis. Inflammasomes, multicomplex cytosolic proteins, generate much of this inflammation, including the activation of the cytokine interleukin (IL)-1β. Inflammation generated by IL-1β is present in several disease states, including atherosclerosis, diabetes, and arthritis. IL-1β is activated when a specific inflammasome, nucleotide-binding domain–like receptor protein 3, induces cleavage of pro–IL-1β into its active form. Nucleotide-binding domain–like receptor protein 3 is up-regulated in lung cancer; IL-1β binds to its receptor and activates signaling pathways, including the MAPK, cyclooxygenase, and nuclear factor–κB pathways, leading to macrophage activation, intratumoral accumulation of immunosuppressive myeloid cells, and tumor growth, invasiveness, metastasis, and angiogenesis. Evidence suggests a role for IL-1β and some of its downstream effectors (e.g., IL-6, IL-8, C-reactive protein, cyclooxygenase-2) as prognostic markers in many malignancies, including lung cancer.

Methods

A phase III cardiovascular study of canakinumab, a human immunoglobulin Gk monoclonal antibody with high affinity and specificity for IL-1β, was conducted in patients who had a myocardial infarction.

Results

A subanalysis of this study found that treatment with canakinumab substantially reduced incident lung cancer and lung cancer mortality in a dose-dependent manner.

Conclusions

A phase III trial is currently recruiting participants to evaluate canakinumab as adjuvant treatment versus placebo in patients with lung cancer. Other studies are investigating combinations of established antineoplastic agents and canakinumab in both early- and advanced-stage NSCLC.

Hydroquinone exposure alters the morphology of lymphoid organs in vaccinated C57Bl/6 mice

The influenza is a common viral infection that can be fatal, especially in high-risk groups such as children, pregnant women, elderly, and immune-deficient individuals. Vaccination is the most efficient approach to prevent the spreading of viral infection and promote individual and public health. In contrast, exposure to environmental pollutants such as cigarette smoke reduces the efficacy of vaccination. We investigated whether chronic exposure to hydroquinone (HQ), the most abundant compound of the tobacco particulate phase, could impair the adaptive immune responses elicited by influenza vaccination. For this, adult male C57BL/6 mice were daily exposed to either nebulized HQ or PBS for 1 h for a total of eight weeks. At weeks 6 and 8, the mice were primed and boosted with the trivalent influenza vaccine via IM respectively. Although the HQ exposure did not alter the body weight of the mice and the biochemical and hematological parameters, the pollutant increased the oxidative stress in splenocytes of immunized animals, modified the morphology of spleen follicles, and augmented the size of their lymph nodes. The lymphoid organs of HQ-exposed mice presented a similar number of vaccine-specific IgG-secreting cells, titers of vaccine-specific total IgG, and respective subclasses. Transcriptome studies with HQ, benzene, or cigarette smoke exposure were also analyzed. The genes up-regulated upon pollutant exposure were associated with neutrophil migration and were shown to be co-expressed with antibody-secreting cell genes. Therefore, these findings suggest that HQ exposure may trigger an immune-compensatory mechanism that enhances the humoral responses induced by influenza vaccination.

Cigarette smoke extract modulates Pseudomonas aeruginosa bacterial load via USP25/HDAC11 axis in lung epithelial cells

Cigarette smoking increases susceptibility for microbial infection in respiratory system. However, the underlying molecular mechanism(s) is not fully elucidated. Here we report that cigarette smoking extract (CSE) increases bacterial load in lung epithelial cells via downregulation of the ubiquitin-specific protease 25 (USP25)/histone deacetylase 11 (HDAC11) axis. CSE treatment decreases HDAC11 at protein level in lung epithelial cells without significant changes of its transcription. Concomitantly, CSE treatment accelerates a ubiquitin-specific protease USP25 ubiquitination and degradation. Coimmunoprecipitation studies showed that USP25 associated with HDAC11. USP25 catalyzes deubiquitination of HDAC11, which regulates HDAC11 protein stability. CSE-mediated degradation of USP25 thereafter reduces HDAC11 at the protein level. Interestingly, CSE-downregulated USP25/HDAC11 axis increases the bacterial load of Pseudomonas aeruginosa in lung epithelial cells. These findings suggest that CSE-downregulated USP25 and HDAC11 may contribute to high susceptibility of bacterial infection in the cigarette smoking population.

Dietary Inflammatory Index and Non-Communicable Disease Risk: A Narrative Review

There are over 1,000,000 publications on diet and health and over 480,000 references on inflammation in the National Library of Medicine database. In addition, there have now been over 30,000 peer-reviewed articles published on the relationship between diet, inflammation, and health outcomes. Based on this voluminous literature, it is now recognized that low-grade, chronic systemic inflammation is associated with most non-communicable diseases (NCDs), including diabetes, obesity, cardiovascular disease, cancers, respiratory and musculoskeletal disorders, as well as impaired neurodevelopment and adverse mental health outcomes. Dietary components modulate inflammatory status. In recent years, the Dietary Inflammatory Index (DII®), a literature-derived dietary index, was developed to characterize the inflammatory potential of habitual diet. Subsequently, a large and rapidly growing body of research investigating associations between dietary inflammatory potential, determined by the DII, and risk of a wide range of NCDs has emerged. In this narrative review, we examine the current state of the science regarding relationships between the DII and cancer, cardiometabolic, respiratory and musculoskeletal diseases, neurodevelopment, and adverse mental health outcomes. We synthesize the findings from recent studies, discuss potential underlying mechanisms, and look to the future regarding novel applications of the adult and children's DII (C-DII) scores and new avenues of investigation in this field of nutritional research.

Soluble Wood Smoke Extract Promotes Barrier Dysfunction in Alveolar Epithelial Cells through a MAPK Signaling Pathway

Wildfire smoke induces acute pulmonary distress and is of particular concern to risk groups such as the sick and elderly. Wood smoke (WS) contains many of the same toxic compounds as those found in cigarette smoke (CS) including polycyclic aromatic hydrocarbons, carbon monoxide, and free radicals. CS is a well-established risk factor for respiratory diseases such as asthma and COPD. Limited studies investigating the biological effects of WS on the airway epithelium have been performed. Using a cell culture-based model, we assessed the effects of a WS-infused solution on alveolar epithelial barrier function, cell migration, and survival. The average geometric mean of particles in the WS was 178 nm. GC/MS analysis of the WS solution identified phenolic and cellulosic compounds. WS exposure resulted in a significant reduction in barrier function, which peaked after 24 hours of continuous exposure. The junctional protein E-cadherin showed a prominent reduction in response to increasing concentrations of WS. Furthermore, WS significantly repressed cell migration following injury to the cell monolayer. There was no difference in cell viability following WS exposure. Mechanistically, WS exposure induced activation of the p44/42, but not p38, MAPK signaling pathway, and inhibition of p44/42 phosphorylation prevented the disruption of barrier function and loss of E-cadherin staining. Thus, WS may contribute to the breakdown of alveolar structure and function through a p44/42 MAPK-dependent pathway and may lead to the development and/or exacerbation of respiratory pathologies with chronic exposure.

Cigarette Smoke Induced Lung Barrier Dysfunction, EMT, and Tissue Remodeling: A Possible Link between COPD and Lung Cancer

Chronic obstructive pulmonary disease (COPD) and lung cancer, closely related to smoking, are major lung diseases affecting millions of individuals worldwide. The generated gas mixture of smoking is proved to contain about 4,500 components such as carbon monoxide, nicotine, oxidants, fine particulate matter, and aldehydes. These components were considered to be the principle factor driving the pathogenesis and progression of pulmonary disease. A large proportion of lung cancer patients showed a history of COPD, which demonstrated that there might be a close relationship between COPD and lung cancer. In the early stages of smoking, lung barrier provoked protective response and DNA repair are likely to suppress these changes to a certain extent. In the presence of long-term smoking exposure, these mechanisms seem to be malfunctioned and lead to disease progression. The infiltration of inflammatory cells to mucosa, submucosa, and glandular tissue caused by inhaled cigarette smoke is responsible for the destruction of matrix, blood supply shortage, and epithelial cell death. Conversely, cancer cells have the capacity to modulate the proliferation of epithelial cells and produce of new vascular networks. Comprehension understanding of mechanisms responsible for both pathologies is necessary for the prevention and treatment of COPD and lung cancer. In this review, we will summarize related articles and give a glance of possible mechanism between cigarette smoking induced COPD and lung cancer.

Repeated Exposure to Streptococcus pneumoniae Exacerbates Chronic Obstructive Pulmonary Disease

Streptococcus pneumoniae is commonly found in patients with chronic obstructive pulmonary disease (COPD) and is linked to acute exacerbation of COPD. However, current clinical therapy neglects asymptomatic insidious S. pneumoniae colonization. We studied the roles of repeated exposure to S. pneumoniae in COPD progression using a mouse model. C57BL/6J mice were intranasally inoculated with S. pneumoniae ST262 every 4 weeks with or without cigarette smoke (CS) exposure up to 20 weeks to maintain persistent S. pneumoniae presence in the lower airways. Streptococcus pneumoniae enhanced CS-induced inflammatory cell infiltration at 12 to 20 weeks of exposure. Streptococcus pneumoniae also increased CS-induced release of inflammatory cytokines, including IL-1β, tumor necrosis factor-α, IL-12 (p70), and IL-5 at 20 weeks of exposure. Moreover, a combination of CS and S. pneumoniae caused alveolar epithelial injury, a decline in lung function, and an increased expression of platelet-activating factor receptor and bacterial load. Our results suggest that repeated exposure to S. pneumoniae in lower airways exacerbates CS-induced COPD.

Immunometabolism and Pulmonary Infections: Implications for Protective Immune Responses and Host-Directed Therapies

The biology and clinical efficacy of immune cells from patients with infectious diseases or cancer are associated with metabolic programming. Host immune- and stromal-cell genetic and epigenetic signatures in response to the invading pathogen shape disease pathophysiology and disease outcomes. Directly linked to the immunometabolic axis is the role of the host microbiome, which is also discussed here in the context of productive immune responses to lung infections. We also present host-directed therapies (HDT) as a clinically viable strategy to refocus dysregulated immunometabolism in patients with infectious diseases, which requires validation in early phase clinical trials as adjuncts to conventional antimicrobial therapy. These efforts are expected to be continuously supported by newly generated basic and translational research data to gain a better understanding of disease pathology while devising new molecularly defined platforms and therapeutic options to improve the treatment of patients with pulmonary infections, particularly in relation to multidrug-resistant pathogens.