Sputum matrix metalloproteinase-9 is associated with the degree of emphysema on computed tomography in COPD

The respiratory cytotoxicity of typical organophosphorus flame retardants on five different respiratory tract cells: Which are the most sensitive one?

Triphenyl phosphate (TPHP) is a frequently used flame retardant and indoor semi-volatile pollutant exposing humans with endocrinal disrupting effects. However, its respiratory tract toxicity remains unclear. Herein, we mainly focused on exploring the cytotoxicity of TPHP to the cells from five different parts of the human respiratory tract (from top to bottom): human nasal epithelial (HNEpC) cells, human bronchial epithelial (16HBE) cells, normal nasopharyngeal epithelial (NP69) cells, human lung epithelial cells (Beas-2B) cells, and human lung fibrocells (HFL1 cells) cells. The cell viability, micronucleus induction, endoplasmic reticulum stress gene, intracellular Ca²⁺ concentration, mitochondrial membrane potential (MMP) were investigated in short-term as well as extended exposure of TPHP. HFL1 and HNEpC cells were found to be irreversible damage, while other three type cells achieved homeostasis through self-rescue. Moreover, expression of downstream genes of Nrf2 signaling pathway were upregulated for 1.3-7.0 times and glutathione detoxification enzyme activity changed for 2-10 (U/mg protein) in HNEpC cells. Furthermore, the vascular endothelial growth factor (VEGF), a disease-related factor, increased 1.0-3.5-fold in HNEpC cells. RNA-sequencing results suggested that protein linkage recombination, molecular function regulation and metabolic processes signal pathway were all affected by TPHP exposure in HNEpC. This is a first report to compare respiratory cytotoxicity in whole human respiratory tract under OPFR exposure and found HNEpC cells were the most sensitive target of TPHP. Molecular biological mechanisms uncovered that TPHP exposure in HNEpC can induce the activation of MAPK signal pathway and demonstrate potential respiratory growth differentiation and stress disorder in human nasal cells upon TPHP exposure.

Effects of icariin on cell injury and glucocorticoid resistance in BEAS-2B cells exposed to cigarette smoke extract

Glucocorticoids (GCs) exert a therapeutic effect in numerous chronic inflammatory diseases. However, chronic obstructive pulmonary disease (COPD) tends to be GC-resistant. Icariin, a major component of flavonoids isolated from Epimedium brevicornum Maxim (Berberidaceae), significantly relieves symptoms in patients with COPD. However, the mechanism of action remains unclear and further investigation is required to establish whether it may serve as an alternative or complementary therapy for COPD. The aim of the present study was to determine the effects of icariin in human bronchial epithelial cells exposed to cigarette smoke extract (CSE) and to determine whether icariin reverses GC resistance. The results revealed that icariin significantly increased the proliferation of CSE-exposed cells. Furthermore, icariin significantly increased protein expression of the anti-inflammatory factor interleukin (IL)-10 and significantly decreased protein expression of the pro-inflammatory factors IL-8 and tumor necrosis factor α. Icariin also attenuated the expression of the cellular matrix remodelling biomarkers matrix metallopeptidase 9 and tissue inhibitor of metalloproteinase 1, and decreased the production of reactive oxygen species (ROS). In addition, icariin regulated the expression of GC resistance-related factors, such as GC receptors, histone deacetylase 2, nuclear factor erythroid-2-related factor 2 and nuclear factor κ B. The results obtained in the present study suggested that icariin may decrease CSE-induced inflammation, airway remodelling and ROS production by mitigating GC resistance. In conclusion, icariin may potentially be used in combination with GCs to increase therapeutic efficacy and reduce GC resistance in COPD.

Oral feeding with probiotic Lactobacillus rhamnosus attenuates cigarette smoke-induced COPD in C57Bl/6 mice: Relevance to inflammatory markers in human bronchial epithelial cells

COPD is a prevalent lung disease with significant impacts on public health. Affected airways exhibit pulmonary neutrophilia and consequent secretion of pro-inflammatory cytokines and proteases, which result in lung emphysema. Probiotics act as nonspecific modulators of the innate immune system that improve several inflammatory responses. To investigate the effect of Lactobacillus rhamnosus (Lr) on cigarette smoke (CS)-induced COPD C57Bl/6 mice were treated with Lr during the week before COPD induction and three times/week until euthanasia. For in vitro assays, murine bronchial epithelial cells as well as human bronchial epithelial cells exposed to cigarette smoke extract during 24 hours were treated with Lr 1 hour before CSE addition. Lr treatment attenuated the inflammatory response both in the airways and lung parenchyma, reducing inflammatory cells infiltration and the production of pro-inflammatory cytokines and chemokines. Also, Lr-treated mice presented with lower metalloproteases in lung tissue and lung remodeling. In parallel to the reduction in the expression of TLR2, TLR4, TLR9, STAT3, and NF-κB in lung tissue, Lr increased the levels of IL-10 as well as SOCS3 and TIMP1/2, indicating the induction of an anti-inflammatory environment. Similarly, murine bronchial epithelial cells as well as human bronchial epithelial cells (BEAS) exposed to CSE produced pro-inflammatory cytokines and chemokines, which were inhibited by Lr treatment in association with the production of anti-inflammatory molecules. Moreover, the presence of Lr also modulated the expression of COPD-associated transcription found into BALF of COPD mice group, i.e., Lr downregulated expression of NF-κB and STAT3, and inversely upregulated increased expression of SOCS3. Thus, our findings indicate that Lr modulates the balance between pro- and anti-inflammatory cytokines in human bronchial epithelial cells upon CS exposure and it can be a useful tool to improve the lung inflammatory response associated with COPD.

Liuweibuqi capsules improve pulmonary function in stable chronic obstructive pulmonary disease with lung-qi deficiency syndrome by regulating STAT4/STAT6 and MMP-9/TIMP-1

Context: Liuweibuqi (LWBQ) capsule has been reported to influence symptoms of patients with chronic obstructive pulmonary disease (COPD); however, specific function of LWBQ capsules in COPD with lung-qi deficiency syndrome remains elusive.Objective: This study investigates effect of LWBQ capsules on STAT4/STAT6 and MMP-9/TIMP-1 expression and pulmonary function in stable COPD with lung-qi deficiency syndrome.Materials and methods: Totally, 429 patients diagnosed with stable COPD and lung-qi deficiency syndrome were treated with starch capsules (each time for 9 capsules), or different doses: low (each dose for 8 capsules and 1 LWBQ capsules), medium (each time for 6 capsules and 3 LWBQ capsules), or high (each time for 9 LWBQ capsules) of LWBQ capsules for 30 days, 3 times a day. Forced expiratory volume in 1 s (FEV1), forced vital capacity (FVC), FEV1/FVC% and DLco%pred were evaluated by pulmonary function meter. STAT4/STAT6 and MMP-9/TIMP-1 expression was assessed by RT-qPCR and western blot analysis, and serum concentrations of IL-4, IFN-γ and IL-6 by ELISA.Results: Spearman rank correlation analysis and ROC curve showed that STAT4/STAT6 and MMP-9/TIMP-1 affected pulmonary functions and curative effect of stable COPD with lung-qi deficiency syndrome. After LWBQ capsule treatment, FEV1, FVC, FEV1/FVC% and DLco%pred elevated; STAT4/STAT6, MMP-9/TIMP-1, IFN-γ and IL-6 expression declined whereas IL-4 expression increased (p < 0.05). Logistic regression analysis demonstrated that FEV1/FVC was negatively correlated with STAT4/STAT6 and MMP-9/TIMP-1 expression in COPD patients.Conclusions: LWBQ capsules play a beneficial role in pulmonary function of stable COPD with lung-qi deficiency syndrome via STAT4/STAT6 and MMP-9/TIMP-1.

Modificated Mahuang-Tang, a traditional herbal medicine suppresses inflammatory responses induced by cigarette smoke in human airway epithelial cell and mice

BACKGROUND

Cigarette smoke (CS) is a major contributor to the high incidence of chronic obstructive pulmonary disease (COPD) featured as chronic inflammation and airway obstruction. Mahuang-Tang is a traditional polyherbal mixture composed of four different herbs. It is widely used in Asia as a remedy for allergic reaction and inflammation.

PURPOSE

We investigated the effects of a modificated Mahuang-Tang water extract (MTWE) against airway inflammation caused by CS and lipopolysaccharide (LPS) in mice and cigarette smoke condensate (CSC)-stimulated NCI-H292 cells.

METHODS

CS exposed to animals for 1 h per day from day 1 to day 7 and treated with LPS intranasally on day 4. One hour before CS exposure, animals were received MTWE (50 or 100 mg/kg) by oral gavage. Inflammatory cell count and cytokines levels were measured in the bronchoalveolar lavage fluid. Expression levels of matrix metalloprotease-9 (MMP-9) and extracellular signal-regulated kinase (Erk) were analyzed by western blotting.

RESULTS

MTWE markedly decreased the neutrophil and other inflammatory cell counts in the bronchoalveolar lavage fluid and reduced proinflammatory mediators as evidenced by the decreases in inflammatory cell recruitment in lung tissue. Furthermore, MTWE meaningfully declined MMP-9 expression and reduced the Erk phosphorylation, caused by the CS and LPS exposure. In in vitro experiments, MTWE suppressed the elevated expression of proinflammatory cytokines induced by CSC treatment. MTWE reduced Erk phosphorylation and MMP-9 expression in CSC-stimulated H292 cells.

CONCLUSION

Overall, MTWE effectively inhibited the pulmonary inflammation and MMP-9 expression caused by the CS and LPS exposure, which was closely involved in suppression of Erk phosphorylation. These results suggest that MTWE possesses a potential for the treatment of COPD.

Overexpression of matrix metalloproteinase-9 in adolescents with primary spontaneous pneumothorax for surgical intervention

OBJECTIVE

To determine gene expression profiles associated with bullae formation in patients with primary spontaneous pneumothorax and to identify candidate genes associated with surgical intervention.

METHODS

Twenty-four adolescents with primary spontaneous pneumothorax were enrolled prospectively. A global gene expression analysis of 9 paired lung biopsies (lesion and normal adjacent sites) was performed to identify differentially expressed genes associated with spontaneous pneumothorax. Pathway and network analysis was performed using the Database for Annotation, Visualization and Integrated Discovery web tool. Candidate genes and encoding proteins were assessed in blood samples and compared between patients with pneumothorax and healthy control patients.

RESULTS

A total of 1519 differentially expressed transcripts corresponding to known genes were identified comparing the lesion lung with paired adjacent normal lung. The altered genes were mainly associated with focal adhesion and extracellular matrix-receptor interaction pathways. Genes involved in proteolysis and peptidase activity were up-regulated predominantly, especially matrix metalloproteinase-1 and -9 genes. Compared with the recovery stage, blood levels of matrix metalloproteinase-9/tissue inhibitor of metalloproteinase-1 were increased at the acute stage in patients with pneumothorax and, when compared between patients treated operatively with those treated nonoperatively, were also significantly greater. In addition, ratios of their serum levels were significantly greater in patients with pneumothorax compared with healthy control patients. Furthermore, matrix metalloproteinase-9 was predominantly overexpressed in neutrophils, alveolar macrophages, and mesothelial cells of lung biopsies.

CONCLUSIONS

An imbalance of cell-extracellular matrix interactions appears to be associated with primary spontaneous pneumothorax. Matrix metalloproteinase-9 overexpression may particularly play a role in contributing to pleural porosity for surgical intervention.

The Effects of Electronic Cigarette (ECIG)-Generated Aerosol and Conventional Cigarette Smoke on the Mucociliary Transport Velocity (MTV) Using the Bullfrog (R. catesbiana) Palate Paradigm

Background: While ECIGs are under scrutiny concerning safety, particularly in reference to the physiological impact that aerosolized ECIG liquid (E-liquid) may have on respiratory tissues, others believe that ECIGs are a “Harm Reduction” alternative to conventional cigarettes. Previous studies investigating ciliated respiratory epithelium indicate that smoking shortens cilia length, reduces cilia beat frequency and disrupts respiratory epithelium, which most likely contributes to the inhibition of mucocilliary clearance. Monitoring mucous clearance of respiratory tissues exposed to ECIG-generated aerosol or conventional cigarette smoke, as indexed by mucous transport velocity (MTV), is one way to gauge the impact aerosol and smoke have on the respiratory tract. Therefore, we designed an experiment to test the effect of ECIG-generated aerosol and smoke on MTV using the frog palate paradigm.

Methods: Peristaltic pumps transport ECIG-generated aerosol and conventional cigarette smoke into custom-made chambers containing excised bullfrog palates. MTVs were determined before exposure, immediately after exposure and approximately 1 day following exposure. MTVs were also determined (at the same time points) for palates exposed to air (control). Surface and cross sectional SEM images of palates from all three groups were obtained to support MTV data.

Results: The results indicate that ECIG-generated aerosol has a modest inhibitory effect (p < 0.05) on MTV 1 day post-exposure (0.09 ± 0.01) compared to control MTV (0.16 ± 0.03 mm/s). In contrast, smoke completely inhibits MTV from 0.14 ± 0.03 mm/s immediately before exposure to 0.00 mm/sec immediately after exposure and the MTV is unable to recover 1 day later. SEM images of control palates and palates exposed to ECIG-generated aerosol both show cilia throughout their epithelial surface, while some areas of palates exposed to smoke are completely devoid of cilia. Additionally, the epithelial thickness of aerosol-exposed palates appears thicker than control palates while smoke-exposed palates appear to be thinner due to epithelial disruption.

Conclusions: These results indicate that ECIG-generated aerosol has only a modest effect on mucocilary clearance of bullfrog palates and aerosol sedimentation accounts for epithelial thickening. In accordance with the primary literature, conventional cigarette smoke dramatically inhibits mucociliary clearance and is, in part, due to decreased number of cilia and disruption of the smoke-exposed epithelium.

Eosinophilic and Neutrophilic Airway Inflammation in the Phenotyping of Mild-to-Moderate Asthma and Chronic Obstructive Pulmonary Disease

Asthma and chronic obstructive pulmonary disease (COPD) are heterogeneous diseases with different inflammatory phenotypes. Various inflammatory mediators play a role in these diseases. The aim of this study was to analyze the neutrophilic and eosinophilic airway and systemic inflammation as the phenotypic characterization of patients with asthma and COPD. Twenty-four patients with asthma and 33 patients with COPD were enrolled in the study. All the patients were in mild-to-moderate stage of disease, and none of them were treated with inhaled corticosteroids. Concentrations of IL-6, neutrophil elastase (NE), matrix metalloproteinase 9 (MMP-9), eosinophil cationic protein (ECP), and IL-33 and IL-17 in serum and induced sputum (IS) were measured by enzyme-linked immunosorbent assay (ELISA). The cellular composition of blood and IS was evaluated. Hierarchical clustering of patients was performed for the combination of selected clinical features and mediators. Asthma and COPD can be differentiated based on eosinophilic/neutrophilic systemic or airway inflammation with unsatisfactory efficiency. Hierarchical clustering of patients based on blood eosinophil percentage and clinical data revealed two asthma clusters differing in the number of positive skin prick tests and one COPD cluster with two subclusters characterized by low and high blood eosinophil concentrations. Clustering of patients according to IS measurements and clinical data showed two main clusters: pure asthma characterized by high eosinophil/atopy status and mixed asthma and COPD cluster with low eosinophil/atopy status. The neutrophilic phenotype of COPD was associated with more severe airway obstruction and hyperinflation.

Distinct emphysema subtypes defined by quantitative CT analysis are associated with specific pulmonary matrix metalloproteinases

BACKGROUND

Emphysema is characterised by distinct pathological sub-types, but little is known about the divergent underlying aetiology. Matrix-metalloproteinases (MMPs) are proteolytic enzymes that can degrade the extracellular matrix and have been identified as potentially important in the development of emphysema. However, the relationship between MMPs and emphysema sub-type is unknown. We investigated the role of MMPs and their inhibitors in the development of emphysema sub-types by quantifying levels and determining relationships with these sub-types in mild-moderate COPD patients and ex/current smokers with preserved lung function.

METHODS

Twenty-four mild-moderate COPD and 8 ex/current smokers with preserved lung function underwent high resolution CT and distinct emphysema sub-types were quantified using novel local histogram-based assessment of lung density. We analysed levels of MMPs and tissue inhibitors of MMPs (TIMPs) in bronchoalveolar lavage (BAL) and assessed their relationship with these emphysema sub-types.

RESULTS

The most prevalent emphysema subtypes in COPD subjects were mild and moderate centrilobular (CLE) emphysema, while only small amounts of severe centrilobular emphysema, paraseptal emphysema (PSE) and panlobular emphysema (PLE) were present. MMP-3, and -10 associated with all emphysema sub-types other than mild CLE, while MMP-7 and -8 had associations with moderate and severe CLE and PSE. MMP-9 also had associations with moderate CLE and paraseptal emphysema. Mild CLE occurred in substantial quantities irrespective of whether airflow obstruction was present and did not show any associations with MMPs.

CONCLUSION

Multiple MMPs are directly associated with emphysema sub-types identified by CT imaging, apart from mild CLE. This suggests that MMPs play a significant role in the tissue destruction seen in the more severe sub-types of emphysema, whereas early emphysematous change may be driven by a different mechanism.

TRIAL REGISTRATION

Trial registration number NCT01701869 .

Present and future utility of computed tomography scanning in the assessment and management of COPD

Computed tomography (CT) is the modality of choice for imaging the thorax and lung structure. In chronic obstructive pulmonary disease (COPD), it used to recognise the key morphological features of emphysema, bronchial wall thickening and gas trapping. Despite this, its place in the investigation and management of COPD is yet to be determined, and it is not routinely recommended. However, lung CT already has important clinical applications where it can be used to diagnose concomitant pathology and determine which patients with severe emphysema are appropriate for lung volume reduction procedures. Furthermore, novel quantitative analysis techniques permit objective measurements of pulmonary and extrapulmonary manifestations of the disease. These techniques can give important insights into COPD, and help explore the heterogeneity and underlying mechanisms of the condition. In time, it is hoped that these techniques can be used in clinical trials to help develop disease-specific therapy and, ultimately, as a clinical tool in identifying patients who would benefit most from new and existing treatments. This review discusses the current clinical applications for CT imaging in COPD and quantification techniques, and its potential future role in stratifying disease for optimal outcome.

Relationship between pulmonary matrix metalloproteinases and quantitative CT markers of small airways disease and emphysema in COPD

BACKGROUND

Matrix metalloproteinases (MMPs) are proteolytic enzymes that can degrade the extracellular matrix and drive tissue remodelling, key processes in the pathogenesis of COPD. The development of small airway disease has been identified as a critical mechanism in the early development of airflow obstruction but the contribution of MMPs in human disease is poorly characterised.

OBJECTIVES

We investigated the role of MMPs and inflammatory cytokines in the lung by quantifying levels and determining relationships with the key pathological components of COPD in patients and healthy controls.

METHODS

We analysed levels of MMPs and inflammatory cytokines in bronchoalveolar lavage from 24 COPD and 8 control subjects. Each subject underwent spirometry and high-resolution CT. Image analysis quantitatively assessed emphysema, bronchial wall thickening and small airways disease.

RESULTS

Multiple MMPs (MMP-1, -2, -3, -8, -9 and -10) and cytokines (interleukin (IL) 6 and IL-8) were elevated in lungs of subjects with COPD. MMP-3, -7, -8, -9, -10 and -12 concentrations closely associated with CT markers of small airways disease. Emphysema severity was also associated with MMP-3, -7 and -10. However, there were no strong relationships between MMPs and bronchial wall thickness of the larger airways.

CONCLUSIONS

Pulmonary MMP concentrations are directly associated with the extent of gas trapping and small airways disease identified on CT scan. This study suggests that MMPs play a significant role in small airways remodelling, a key feature in the pathogenesis of COPD.

TRIAL REGISTRATION NUMBER

NCT01701869.

Anti-malarial drug artesunate protects against cigarette smoke-induced lung injury in mice

Cigarette smoking is the primary cause of chronic obstructive pulmonary disease (COPD), which is mediated by lung infiltration with inflammatory cells, enhanced oxidative stress, and tissue destruction. Anti-malarial drug artesunate has been shown to possess anti-inflammatory and anti-oxidative actions in mouse asthma models. We hypothesized that artesunate can protect against cigarette smoke-induced acute lung injury via its anti-inflammatory and anti-oxidative properties. Artesunate was given by oral gavage to BALB/c mice daily 2h before 4% cigarette smoke exposure for 1h over five consecutive days. Bronchoalveolar lavage (BAL) fluid and lungs were collected for analyses of cytokines, oxidative damage and antioxidant activities. Bronchial epithelial cell BEAS-2B was exposed to cigarette smoke extract (CSE) and used to study the mechanisms of action of artesunate. Artesunate suppressed cigarette smoke-induced increases in BAL fluid total and differential cell counts; levels of IL-1β, MCP-1, IP-10 and KC; and levels of oxidative biomarkers 8-isoprostane, 8-OHdG and 3-nitrotyrosine in a dose-dependent manner. Artesunate promoted anti-oxidant catalase activity and reduced NADPH oxidase 2 (NOX2) protein level in the lungs from cigarette smoke-exposed mice. In BEAS-2B cells, artesunate suppressed pro-inflammatory PI3K/Akt and p44/42 MAPK signaling pathways, and increased nuclear Nrf2 accumulation in response to CSE. Artesunate possesses anti-inflammatory and anti-oxidative properties against cigarette smoke-induced lung injury, probably via inhibition of PI3K and p42/22 MAPK signaling pathways, augmentation of Nrf2 and catalase activities, and reduction of NOX2 level. Our data suggest that artesunate may have therapeutic potential for treating COPD.