Involvement of Oxidative Stress in COPD

Effect of age, COPD severity, and cigarette smoke exposure on bronchial epithelial barrier function

We investigated the effect of age, cigarette smoke, and chronic obstructive pulmonary disease (COPD) severity on epithelial barrier function. Primary bronchial epithelial cells (PBECs) were obtained from bronchial brushings in eight younger and eight older never-smokers; seven older ex-smokers without COPD, eight patients with COPD Global Initiative for Chronic Obstructive Lung Disease (GOLD) I-III and six patients with COPD GOLD IV, and cultured in the absence/presence of cigarette smoke extract (CSE). Epithelial barrier function was assessed by electric resistance sensing and expression of junctional and antioxidant genes/proteins quantified by qPCR/immunodetection. Epithelial barrier function was comparable between PBECs from younger and older never-smokers. PBECs from ex-smokers had significantly lower barrier function compared with never-smokers, with a further decrease in COPD GOLD IV. CSE decreased epithelial barrier function from which PBECs from never-smokers, but not ex-smokers with and without COPD, recovered. Restoration of barrier function was accompanied by increased expression of barrier and antioxidant genes. At baseline, PBECs from ex-smokers with and without COPD had higher expression of junctional and antioxidant genes compared with never-smokers. However, exposure to CSE increased antioxidant (SOD1-3, CAT) gene expression only in PBECs from never-smokers and ex-smokers without COPD. In conclusion, our data indicate that cigarette smoking and COPD severity are associated with reduced epithelial barrier function, which is potentially driven by an imbalance in the antioxidant response.NEW & NOTEWORTHY Cigarette smoking and chronic obstructive pulmonary disease (COPD) severity are associated with reduced epithelial barrier function that is potentially driven by an imbalance in the antioxidant response.

Caspase inhibition restores collagen Iα1 and fibronectin release in cigarette smoke extract-exposed human lung fibroblasts

Chronic obstructive pulmonary disease (COPD) is a progressive lung disease characterized by obstructed airflow, airway remodeling, and inflammation, with cigarette smoke (CS) exposure being the main risk factor. Although CS extract (CSE) has been shown to activate caspases in various cell types, the role of caspases in human lung fibroblasts (hLFs) in COPD remains poorly understood. Recent studies have linked caspases to extracellular matrix (ECM) remodeling in skin and kidney fibrosis. Caspase activation can be triggered by oxidative stress, with active caspase-3 executing the pore-forming protein gasdermin E (GSDME) in the cleaved N-terminal form GSDME-NT. We investigated whether CSE activates caspases and GSDME in hLFs and their role in ECM remodeling. MRC-5 lung fibroblasts were treated with CSE with or without the antioxidant N-acetyl-cysteine (NAC) and the caspase-8 inhibitor z-IETD-fmk. We measured the effects on caspase-1-8-3/7 activation, GSDME cleavage, ECM remodeling (procollagen Iα1, COLIα1, and fibronectin, FN), and mitochondrial superoxide (mSOX) generation. Key findings were validated in patient-derived hLFs (phLFs). Our results showed that CSE induced caspase-1-8-3/7 activation, mSOX generation, and decreased COLIα1 and FN levels in MRC-5. CSE caused caspase-8-dependent activation of caspase-3, leading to GSDME cleavage. Treatment with NAC inhibited mSOX and caspase activation. Inhibition of caspase-8 and mSOX restored FN and COLIα1 levels. In phLFs, we confirmed caspase-1 and -8 activation, mSOX increase, COLIα1/FN decrease, and the effects of NAC. Our findings highlight the role of the axis caspase-8-3/7-GSDME and mSOX in regulating ECM protein, suggesting that these pathways may contribute to remodeling in COPD.NEW & NOTEWORTHY This research investigates the connection between caspases, gasdermins, and extracellular matrix (ECM) remodeling in the context of cigarette smoke-associated lung diseases. The study found that cigarette smoke extract (CSE) activates caspases and gasdermin E in human lung fibroblasts, leading to decreased ECM protein expression and release. Findings herein reported suggest that targeting the caspase-8-3/7-gasdermin axis and mitochondrial reactive oxygen species may help restore ECM remodeling in chronic lung diseases associated with cigarette smoke exposure.

Dynamics of Inflammatory and Pathological Changes Induced by Single Exposure of Particulate Matter (PM2.5) in Mice: Potential Implications in COPD

Chronic Obstructive Pulmonary Disease (COPD) is a progressive disorder of lungs marked by chronic bronchitis and emphysema. Particulate matter (PM2.5), a major component of air pollution has been correlated with COPD incidence. The present work aimed to understand dynamics of cellular/molecular players behind PM2.5-mediated COPD pathogenesis in mice by conducting dose and time-course studies. Single intratracheal exposure of PM2.5 at a dose of either 100 or 200 μg induced inflammatory response in lungs at 4 days. Time course studies showed that inflammation once triggered by PM2.5 is progressive in nature as reflected by data on BALF inflammatory cells at 7/14 days. Similarly, various cytokines/chemokines (KC/IL-6/TNF-α/IL-1β/G-CSF/MCP-1) peak at either 7 or 14 days. However, inflammation declined sharply at 21 days. Data on LPO/GSH and activities of SOD/Catalase show induction of continuous oxidative stress in lung tissue. Next, enhanced mtROS in the CD11b+ inflammatory cells confirms the redox imbalance in neutrophils/macrophages. A continuous decline in lung function was observed till 28 days. Further, histological analysis of lung tissues at 28 days confirmed the presence of emphysematous lesions, validating the potency of PM2.5 to cause irreversible damage to lungs through complex interplay of various cellular/molecular players which may be exploited as potential preventive/therapeutic targets.

Mapping the Common Barriers to Optimal COPD Care in High and Middle-Income Countries: Qualitative Perspectives from Clinicians

Purpose

Chronic obstructive pulmonary disease (COPD) poses a significant global health burden despite being largely preventable and treatable. Despite the availability of guidelines, COPD care remains suboptimal in many settings, including high-income countries (HICs) and upper-middle-income countries (UMICs), with varied approaches to diagnosis and management. This study aimed to identify common and unique barriers to COPD care across six countries (Australia, Spain, Taiwan, Argentina, Mexico, and Russia) to inform global policy initiatives for improved care.

Methods

COPD care pathways were mapped for each country and supplemented with epidemiological, health-economic, and clinical data from a targeted literature review. Semi-structured interviews with 17 respiratory care clinicians were used to further validate the pathways and identify key barriers. Thematic content analysis was used to generate the themes.

Results

Six themes were common in most HICs and UMICs: "Challenges in COPD diagnosis", "Strengthening the role of primary care", "Fragmented healthcare systems and coordination challenges", "Inadequate management of COPD exacerbations", "Limited access to specialized care" and, "Impact of underfinanced and overloaded healthcare systems". One theme, "Insurance coverage and reimbursement challenges", was more relevant for UMICs. HICs and UMICs differ in patient and healthcare provider awareness, primary care involvement, spirometry access, and availability of specialized care. Both face issues with healthcare fragmentation, guideline adherence, and COPD exacerbation management. In addition, UMICs also grapple with resource limitations and healthcare infrastructure challenges.

Conclusion

Many challenges to COPD care are the same in both HICs and UMICs, underscoring the pervasive nature of these issues. While country-specific issues require customized solutions, there are untapped possibilities for implementing global respiratory strategies that support countries to manage COPD effectively. In addition to healthcare system-level initiatives, there is a crucial need for political prioritization of COPD to allocate the essential resources it requires.

The Potential Important Role of Mitochondrial Rieske Iron-Sulfur Protein as a Novel Therapeutic Target for Pulmonary Hypertension in Chronic Obstructive Pulmonary Disease

Chronic obstructive pulmonary disease (COPD) is the third leading cause of death worldwide, which is often due to pulmonary hypertension (PH). The underlying molecular mechanisms are poorly understood, and current medications are neither specific nor always effective. In this review, we highlight the recent findings on the roles of altered mitochondrial bioenergetics in PH in COPD. We also discuss the central role of mitochondrial reactive oxygen species (ROS) generation mediated by Rieske iron-sulfur protein (RISP) and review the contributions of RISP-dependent DNA damage and NF-κB-associated inflammatory signaling. Finally, the potential importance of mitochondrial RISP and its associated molecules as novel therapeutic targets for PH in COPD are meticulously discussed.

Mechanisms, Pathophysiology and Currently Proposed Treatments of Chronic Obstructive Pulmonary Disease

Chronic obstructive pulmonary disease (COPD) is one of the leading global causes of morbidity and mortality. A hallmark of COPD is progressive airflow obstruction primarily caused by cigarette smoke (CS). CS exposure causes an imbalance favoring pro- over antioxidants (oxidative stress), leading to transcription factor activation and increased expression of inflammatory mediators and proteases. Different cell types, including macrophages, epithelial cells, neutrophils, and T lymphocytes, contribute to COPD pathophysiology. Alteration in cell functions results in the generation of an oxidative and inflammatory microenvironment, which contributes to disease progression. Current treatments include inhaled corticosteroids and bronchodilator therapy. However, these therapies do not effectively halt disease progression. Due to the complexity of its pathophysiology, and the risk of exacerbating symptoms with existing therapies, other specific and effective treatment options are required. Therapies directly or indirectly targeting the oxidative imbalance may be promising alternatives. This review briefly discusses COPD pathophysiology, and provides an update on the development and clinical testing of novel COPD treatments.

The Combination of Cigarette Smoking and Alcohol Consumption Synergistically Increases Reactive Carbonyl Species in Human Male Plasma

Cigarette smoking and alcohol consumption are major risk factors for lifestyle-related diseases. Although it has been reported that the combination of these habits worsens risks, the underlying mechanism remains elusive. Reactive carbonyl species (RCS) cause chemical modifications of biological molecules, leading to alterations in cellular signaling pathways, and total RCS levels have been used as a lipid peroxidation marker linked to lifestyle-related diseases. In this study, at least 41 types of RCS were identified in the lipophilic fraction of plasma samples from 40 subjects using liquid chromatography/electrospray ionization tandem mass spectrometry (LC/ESI-MS/MS). Higher levels of 10 alkanals, 5 trans-2-alkenals, 1 cis-4-alkenal, and 3 alkadienals were detected in the smoking/drinking group (N = 10) as compared to those with either habit (N = 10 each) or without both habits (N = 10) in the analysis of covariances adjusted for age and BMI. The levels of 3 alkanals, 1 trans-2-alkenal, 1 alkadienal, and 1 4-hydroxy-2-alkenal in the smoking/drinking group were significantly higher than those in the no-smoking/drinking and no-smoking/no-drinking groups. These results strongly indicate that the combination of cigarette smoking and alcohol drinking synergistically increases the level and variety of RCS in the circulating blood, and may further jeopardize cellular function.

Overview on Interactive Role of Inflammation, Reactive Oxygen Species, and Calcium Signaling in Asthma, COPD, and Pulmonary Hypertension

Inflammatory signaling is a major component in the development and progression of many lung diseases, including asthma, chronic obstructive pulmonary disorder (COPD), and pulmonary hypertension (PH). This chapter will provide a brief overview of asthma, COPD, and PH and how inflammation plays a vital role in these diseases. Specifically, we will discuss the role of reactive oxygen species (ROS) and Ca²⁺ signaling in inflammatory cellular responses and how these interactive signaling pathways mediate the development of asthma, COPD, and PH. We will also deliberate the key cellular responses of pulmonary arterial (PA) smooth muscle cells (SMCs) and airway SMCs (ASMCs) in these devastating lung diseases. The analysis of the importance of inflammation will shed light on the key questions remaining in this field and highlight molecular targets that are worth exploring. The crucial findings will not only demonstrate the novel roles of essential signaling molecules such as Rieske iron-sulfur protein and ryanodine receptor in the development and progress of asthma, COPD, and PH but also offer advanced insight for creating more effective and new therapeutic targets for these devastating inflammatory lung diseases.

NOX4-Derived ROS Promotes Collagen I Deposition in Bronchial Smooth Muscle Cells by Activating Noncanonical p38MAPK/Akt-Mediated TGF-β Signaling

Background

Airway smooth muscle (ASM) remodeling is a hallmark in chronic obstructive pulmonary disease (COPD). NADPH oxidase 4- (NOX4-) mediated reactive oxygen species (ROS) production plays a crucial role in cell differentiation and extracellular matrix (ECM) synthesis in ASM remodeling. However, the precise mechanisms underpinning its pathogenic roles remain elusive.

Methods

The expression of NOX4 and TGF-β₁ in the airway of the lung was measured in COPD patients and the control group. Cigarette smoke- (CS-) induced emphysema mice were generated, and the alteration of α-SMA, NOX4, TGF-β₁, and collagen I was accessed. The changes of the expression of ECM markers, NOX4, components of TGF-β/Smad, and MAPK/Akt signaling in human bronchial smooth muscle cells (HBSMCs) were ascertained for delineating mechanisms of NOX4-mediated ROS production on cell differentiation and remodeling in human ASM cells.

Results

An increased abundance of NOX4 and TGF-β₁ proteins in the epithelial cells and ASM of lung was observed in COPD patients compared with the control group. Additionally, an increased abundance expression of NOX4 and α-SMA was observed in the lungs of the CS-induced emphysema mouse model. TGF-β₁ displayed abilities to increase the oxidative burden and collagen I production, along with enhanced phosphorylation of ERK, p38MAPK, and p-Akt473 in HBSMCs. These effects of TGF-β₁ could be inhibited by the ROS scavenger N-acetylcysteine (NAC), siRNA-mediated knockdown of Smad3 and NOX4, and pharmacological inhibitors SB203580 (p38MAPK inhibitor) and LY294002 (Akt inhibitor).

Conclusions

NOX4-mediated ROS production alters TGF-β₁-induced cell differentiation and collagen I protein synthesis in HBSMCs in part through the p38MAPK/Akt signaling pathway in a Smad-dependent manner.

Prognostic impact of acute pulmonary triggers in patients with takotsubo syndrome: new insights from the International Takotsubo Registry

AIMS

Acute pulmonary disorders are known physical triggers of takotsubo syndrome (TTS). This study aimed to investigate prevalence of acute pulmonary triggers in patients with TTS and their impact on outcomes.

METHODS AND RESULTS

Patients with TTS were enrolled from the International Takotsubo Registry and screened for triggering factors and comorbidities. Patients were categorized into three groups (acute pulmonary trigger, chronic lung disease, and no lung disease) to compare clinical characteristics and outcomes. Of the 1670 included patients with TTS, 123 (7%) were identified with an acute pulmonary trigger, and 194 (12%) had a known history of chronic lung disease. The incidence of cardiogenic shock was highest in patients with an acute pulmonary trigger compared with those with chronic lung disease or without lung disease (17% vs. 10% vs. 9%, P = 0.017). In-hospital mortality was also higher in patients with an acute pulmonary trigger than in the other two groups, although not significantly (5.7% vs. 1.5% vs. 4.2%, P = 0.13). Survival analysis demonstrated that patients with an acute pulmonary trigger had the worst long-term outcome (P = 0.002). The presence of an acute pulmonary trigger was independently associated with worse long-term mortality (hazard ratio 2.12, 95% confidence interval 1.33-3.38; P = 0.002).

CONCLUSIONS

The present study demonstrates that TTS is related to acute pulmonary triggers in 7% of all TTS patients, which accounts for 21% of patients with physical triggers. The presence of acute pulmonary trigger is associated with a severe in-hospital course and a worse long-term outcome.

Therapeutic effects of black seed oil supplementation on chronic obstructive pulmonary disease patients: A randomized controlled double blind clinical trial

This study sought to examine whether supplementation of Black Seed Oil (BSO) can improve pulmonary function tests (PFTs), inflammation, and oxidant-antioxidant markers in COPD patients. The study involved 100 patients of mild to moderate COPD divided randomly into 2 groups who were appointed to receive standard medication only (control group) or with additional Black Seed Oil (BSO group). They were assessed initially and after 3 months, 44 patients responded in control group and 47 patients in BSO group. BSO group evidenced a significant decreasing in oxidant and inflammatory markers; thiobarbituric acid reactive-substances (TBARS), protein carbonyl (PC) content, interleukin-6 (IL-6), and tumor necrosis factor-α (TNF-α), a significant increase in antioxidants; superoxide dismutase (SOD), catalase (CAT), reduced glutathione (GSH), glutathione peroxidase (GPx), vitamin C, and E, and a significant improvement in PFTs versus control group and baseline levels. Supplementation of Black Seed Oil may be an effective adjunct therapy to improve pulmonary functions, inflammation, and oxidant-antioxidant imbalance in COPD patients.

The Beneficial Effects of Antioxidants in Health And Diseases

Reactive oxygen and nitrogen species can be generated endogenously (by mitochondria, peroxisomes, and phagocytic cells) and exogenously (by pollutions, UV exposure, xenobiotic compounds, and cigarette smoke). The negative effects of free radicals are neutralized by antioxidant molecules synthesized in our body, like glutathione, uric acid, or ubiquinone, and those obtained from the diet, such as vitamins C, E, and A, and flavonoids. Different microelements like selenium and zinc have no antioxidant action themselves but are required for the activity of many antioxidant enzymes. Furthermore, circulating blood proteins are suggested to account for more than 50% of the combined antioxidant effects of urate, ascorbate, and vitamin E. Antioxidants together constitute a mutually supportive defense against reactive oxygen and nitrogen species to maintain the oxidant/antioxidant balance. This article outlines the oxidative and anti-oxidative molecules involved in the pathogenesis of chronic obstructive lung disease. The role of albumin and alpha-1 antitrypsin in antioxidant defense is also discussed.