Exhaled matrix metalloproteinase-9 (MMP-9) in different biological phenotypes of asthma

Turmeric extract alleviates airway inflammation via oxidative stress-driven MAPKs/MMPs pathway

Turmeric (Curcuma longa L.) extract (CLE) has been shown to elicit several pharmacological properties and is widely used in Asian traditional medicine. Herein, we assessed the impact of CLE on airway inflammation in BALB/c mice and A549 cells to clarify the underlying mechanism. An asthmatic mouse model was established by administering ovalbumin (OVA). CLE (100 or 300 mg/kg/day) was orally administered daily from days 18 to 23, with dexamethasone (3 mg/kg/day) used as the positive control. Human airway epithelial cells, A549, were stimulated using recombinant tumor necrosis factor-α. The CLE100 and CLE400 groups exhibited a significant downregulation in eosinophil counts, cytokine levels, and immunoglobulin-E levels. Moreover, CLE administration dose-dependently suppressed oxidative stress and airway inflammation in the lung tissue. CLE administration inhibited the phosphorylation of mitogen-activated protein kinases (MAPKs) and the expression and activity of matrix metalloproteinase (MMP)-9. In vitro, CLE treatment reduced mRNA levels of proinflammatory cytokines, MAPK phosphorylation, and the expression and activity of MMP-2 and MMP-9. Additionally, 50 µg/mL CLE and 2.5 µg/mL curcumin showed similar anti-inflammatory effects. Collectively, our findings revealed that CLE could suppress airway inflammation in asthmatic mice and A549 cells via oxidative stress-driven MAPK/MMPs signaling, suggesting that CLE could be developed as a potential treatment option for patients with asthma.

Camellia sinensis L. alleviates OVA-induced allergic asthma through NF-κB and MMP-9 pathways

Allergic asthma, a type of chronic airway inflammation, is a global health concern because of its increasing incidence and recurrence rates. Camellia sinensis L. yields a variety type of teas, which are also used as medicinal plants in East Asia and are known to have antioxidant, anti-inflammatory, and immune-potentiating properties. Here, we examined the constituents of C. sinensis L. extract (CSE) and evaluated the protective effects of CSE on allergic asthma by elucidating the underlying mechanism. To induce allergic asthma, we injected the sensitization solution (mixture of ovalbumin (OVA) and aluminum hydroxide) into mice intraperitoneally on days 0 and 14. Then, the mice were exposed to 1% OVA by a nebulizer on days 21 to 23, while intragastric administration of CSE (30 and 100 mg/kg) was performed each day on days 18 to 23. We detected five compounds in CSE, including (-)-epigallocatechin, caffeine, (-)-epicatechin, (-)-epigallocatechin gallate, and (-)-epicatechin gallate. Treatment with CSE remarkably decreased the airway hyperresponsiveness, OVA-specific immunoglobulin E level, and inflammatory cell and cytokine levels of mice, with a decrease in inflammatory cell infiltration and mucus production in lung tissue. Treatment with CSE also decreased the phosphorylation of nuclear factor-κB (NF-κB) and the expression of matrix-metalloproteinase (MMP)-9 in asthmatic mice. Our results demonstrated that CSE reduced allergic airway inflammation caused by OVA through inhibition of phosphorylated NF-κB and MMP-9 expression.

8-Iso-prostaglandin F2α as a biomarker of type 2 low airway inflammation and remodeling in adult asthma

BACKGROUND

Although 8-iso-prostaglandin F2a has been proposed as a potential biomarker for oxidative stress in airway diseases, its specific role in asthma remains poorly understood.

OBJECTIVE

To evaluate the diagnostic potential of 8-iso-prostaglandin F2a in assessing airway inflammation, airway remodeling, airway hyperresponsiveness, and oxidative stress in asthma.

METHODS

Blood and urine concentrations of 8-iso-prostaglandin F2a were quantified using liquid chromatography-tandem mass spectrometry in 128 adults with asthma who had maintained antiasthma medications. Their correlations with clinical data, sputum cell counts, lung function parameters, and serum markers of epithelial/neutrophil activity and airway remodeling were then analyzed.

RESULTS

The urinary 8-iso-prostaglandin F2a concentrations were significantly higher in patients with noneosinophilic asthma than in those with eosinophilic asthma (P < .05). The area under the curve was 0.678, indicating moderate diagnostic accuracy for noneosinophilic asthma. There were significant correlations with neutrophilic inflammation markers and airway remodeling markers (all P < .05). Negative correlations were observed with forced expiratory volume in 1 second (%), forced expiratory volume in 1 second/forced vital capacity, forced expiratory flow at 25% to 75% of forced vital capacity, and serum club cell protein 16 levels (all P < .05). High 8-iso-prostaglandin F2a concentrations were also noted in obese and smoking subgroups (all P < .05). However, the serum 8-iso-prostaglandin F2a concentrations were not correlated with these asthma-related parameters.

CONCLUSION

Urinary 8-iso-prostaglandin F2a concentrations are a potential biomarker for phenotyping severe asthma, particularly noneosinophilic asthma, offering oxidative stress-induced epithelial inflammation/remodeling as an additional target in asthma management.

Chronic inhalation of H2S in low concentration induces immunotoxicity and inflammatory effects in lung tissue of rats

Hydrogen sulfide (H2S) is a typical odour compound mainly causing respiratory and central nervous system symptoms. However, the immunotoxicity of inhaled H2S and the underlying mechanisms remain largely unknown. In this study, a low-dose inhalation exposure to H2S was arranged to observe inflammatory response and immunotoxicity in lung tissue of rats. Low concentrations of H2S exposure affected the immune level of pulmonary tissue and peripheral blood. Significant pathological changes in lung tissue in the exposure group were observed. At low concentration, H2S not only induced the upregulation of AQP-4 and MMP-9 expression but also stimulated immune responses, initiating various anti-inflammatory and inflammatory factors, altering tissue homeostatic environments. The TNF and chemokine signaling pathway played an important role which can promote the deterioration of pulmonary inflammatory processes and lead to lung injury and fibrosis. Excessive immune response causes an inflammatory effect and blood-gas barrier damage. These data will be of value in evaluating future occupational health risks and providing technical support for the further development of reliable, sensitive, and easy-to-use screening indicators of exposure injury.

Airborne indoor allergen serine proteases and their contribution to sensitisation and activation of innate immunity in allergic airway disease

Common airborne allergens (pollen, animal dander and those from fungi and insects) are the main triggers of type I allergic disorder in the respiratory system and are associated with allergic rhinitis, allergic asthma, as well as immunoglobulin E (IgE)-mediated allergic bronchopulmonary aspergillosis. These allergens promote IgE crosslinking, vasodilation, infiltration of inflammatory cells, mucosal barrier dysfunction, extracellular matrix deposition and smooth muscle spasm, which collectively cause remodelling of the airways. Fungus and insect (house dust mite and cockroaches) indoor allergens are particularly rich in proteases. Indeed, more than 40 different types of aeroallergen proteases, which have both IgE-neutralising and tissue-destructive activities, have been documented in the Allergen Nomenclature database. Of all the inhaled protease allergens, 85% are classed as serine protease activities and include trypsin-like, chymotrypsin-like and collagenolytic serine proteases. In this article, we review and compare the allergenicity and proteolytic effect of allergen serine proteases as listed in the Allergen Nomenclature and MEROPS databases and highlight their contribution to allergic sensitisation, disruption of the epithelial barrier and activation of innate immunity in allergic airways disease. The utility of small-molecule inhibitors of allergen serine proteases as a potential treatment strategy for allergic airways disease will also be discussed.

The role of matrix metalloproteinase-2 and miR-196a2 in bronchial asthma pathogenesis and diagnosis

Background

Bronchial asthma is a persistent inflammatory respiratory condition that restricts the passage of air and causes hyperresponsiveness. Chronic asthma can be classified into three categories: mild, moderate, and severe. Remodeling took place as the extracellular matrix accumulated in the walls of the airways. Inflammation occurs as a result of the damage caused by matrix metalloproteinase-2 (MMP-2) to basement membrane type IV collagen. The severity of asthma may be associated with miR-196a2. The objective of our study was to investigate the underlying mechanisms and clinical relevance of miR-196a2 and MMP-2 serum levels in relation to the severity of asthma.

Methods

This study recruited 85 controls and 95 asthmatics classified as mild, moderate, or severe. Expression of miR-196a2 was measured by quantitative reverse transcriptase PCR. Using the enzyme-linked immunosorbent assay (ELISA), MMP-2, IL-6, and total immunoglobulin E (IgE) levels in the serum of asthmatics of various grades were compared to a control group. MMP-2's diagnostic and prognostic potential was determined using ROC curve analysis. This study also measured blood Eosinophils and PFTs. We examined MMP-2's connections with IgE, blood Eosinophils, and PFTs.

Results

The current investigation found that miR-196a2 expression was significantly higher in the control group than in asthmatic patients as a whole. The study found that severe asthmatics had higher MMP-2, IL-6, and IgE serum levels than healthy controls. We identified the MMP-2 serum concentration cutoff with great sensitivity and specificity. Significant relationships between MMP-2 serum level and miR-196a2 expression in the patient group with severe asthmatics were found. The MMP-2, IL-6, and IgE serum levels were considerably higher in mild, moderate, and severe asthmatics than controls. The miR-196a2 expression and MMP-2 serum concentration correlated positively with IgE and blood eosinophils % and negatively with all lung function tests in the asthmatic patient group.Conclusion: the study revealed that the elevated miR-196a2 expression and serum concentration of MMP-2, IL-6, and IgE associated with elevated blood eosinophils % is associated with pathophysiology and degree of asthma severity. The miR-196a2 expression and MMP-2 serum concentration have a promising diagnostic and prognostic ability in bronchial asthma.

Impact of obesity on airway remodeling in asthma: pathophysiological insights and clinical implications

The prevalence of obesity among asthma patients has surged in recent years, posing a significant risk factor for uncontrolled asthma. Beyond its impact on asthma severity and patients' quality of life, obesity is associated with reduced lung function, increased asthma exacerbations, hospitalizations, heightened airway hyperresponsiveness, and elevated asthma-related mortality. Obesity may lead to metabolic dysfunction and immune dysregulation, fostering chronic inflammation characterized by increased pro-inflammatory mediators and adipocytokines, elevated reactive oxygen species, and reduced antioxidant activity. This chronic inflammation holds the potential to induce airway remodeling in individuals with asthma and obesity. Airway remodeling encompasses structural and pathological changes, involving alterations in the airway's epithelial and subepithelial layers, hyperplasia and hypertrophy of airway smooth muscle, and changes in airway vascularity. In individuals with asthma and obesity, airway remodeling may underlie heightened airway hyperresponsiveness and increased asthma severity, ultimately contributing to the development of persistent airflow limitation, declining lung function, and a potential increase in asthma-related mortality. Despite efforts to address the impact of obesity on asthma outcomes, the intricate mechanisms linking obesity to asthma pathophysiology, particularly concerning airway remodeling, remain incompletely understood. This comprehensive review discusses current research investigating the influence of obesity on airway remodeling, to enhance our understanding of obesity's role in the context of asthma airway remodeling.

Changes and clinical significance of serum MMP-9, TIMP-1, COX-2, and immune levels in patients with asthma

OBJECTIVE

To detect serum metalloproteinase-9 (MMP-9), tissue inhibitor of metalloproteinases (TIMP-1), cyclooxygenase-2 (COX-2), and T helper cells 1-T helper cells 2 (Th1-Th2) levels in asthma patients and assess their clinical significance.

METHODS

A total of 72 patients experiencing acute asthma (acute group), 66 stable asthma patients (stable group), and 60 healthy volunteers (control group) were included in this study. The levels of TIMP-1, COX-2, and Th1-Th2 in patients with acute asthma were measured following treatment with budesonide aerosol inhalation. In addition, the levels of MMP-9, TIMP-1, COX-2 and Th1-Th2 were compared in patients with different severity of acute asthma before and after treatment.

RESULTS

The serum levels of MMP-9, TIMP-1, and COX-2 showed an increasing trend in the control, stable, and acute groups, while levels of Th1-Th2 showed a sequential decreasing trend, and the differences were statistically significant. Comparison of lung function indexes among the three groups of patients established a negative correlation between serum MMP-9 and its forced vital capacity% predicted (FEV%pred), TIMP-1, and COX-2, and FEV%pred and forced expiratory volume in 1 s-forced vital capacity (FEV1/FVC) levels, but a positive correlation between Th1-Th2 and FEV1/FVC levels in the acute group. A significant difference was observed on comparing the levels of serum MMP-9, TIMP-1, COX-2, and Th1-Th2 in patients with different conditions in the acute group. Specifically, as the condition worsened, a significant increase in serum MMP-9, TIMP-1, and COX-2 levels but a significant decrease in Th1-Th2 levels was observed. After treatment, we observed a significant decrease in serum MMP-9, TIMP-1, and COX-2 levels but a significant increase in Th1-Th2 levels in the acute group.

CONCLUSION

The serum levels of MMP-9, TIMP-1, COX-2, and Th1-Th2 are valuable indicators reflecting the condition of asthma patients and could be considered promising clinical monitoring indicators.

Association Between Blood Eosinophils and Neutrophils With Clinical Features in Adult-Onset Asthma

BACKGROUND

Asthma is a disease that can be separated into different phenotypes and endotypes based on the clinical characteristics and the molecular mechanisms of the condition, respectively.

OBJECTIVE

To assess the association between blood eosinophil and neutrophil counts with clinical and molecular features in patients with adult-onset asthma.

METHODS

Blood eosinophil and neutrophil counts were measured from 203 patients who took part in the Seinäjoki Adult Asthma Study and attended the 12-year follow-up visit. The patients were then divided into four groups (paucigranulocytic [n = 108], neutrophilic [n = 60], eosinophilic [n = 21], and mixed granulocytic [n = 14]), according to eosinophil and neutrophil levels. The cutoff values used to define the groups were 0.30 × 10⁹ · L^-1 for blood eosinophils and 4.4 × 10⁹ · L^-1 for blood neutrophils.

RESULTS

The neutrophilic group had highest body mass index. It was dispensed the highest doses of inhaled corticosteroids during the 12-year follow-up and made the most unplanned respiratory visits. The neutrophilic, eosinophilic, and mixed granulocytic groups had more severe asthma compared with the paucigranulocytic group. The neutrophilic and eosinophilic groups were associated with higher dispensed antibiotics. The eosinophilic group had more nasal polyps, more suspected sinusitis, a greater decline in lung function, and increased levels of periostin, FeNO, and IgE. The neutrophilic group had increased high-sensitivity C-reactive protein, matrix metalloproteinase-9, IL-6, leptin, and soluble urokinase plasminogen activator receptor levels. The mixed granulocytic group showed increased resistin levels together with the neutrophilic group.

CONCLUSIONS

In addition to blood eosinophils, the blood neutrophil count reflects underlying inflammatory patterns and indicates important differences in asthma clinical features and outcomes.

Immunobiology of Steroid-Unresponsive Severe Asthma

Asthma is a heterogeneous respiratory disease characterized by airflow obstruction, bronchial hyperresponsiveness and airway inflammation. Approximately 10% of asthma patients suffer from uncontrolled severe asthma (SA). A major difference between patients with SA from those with mild-to-moderate asthma is the resistance to common glucocorticoid treatments. Thus, steroid-unresponsive uncontrolled asthma is a hallmark of SA. An impediment in the development of new therapies for SA is a limited understanding of the range of immune responses and molecular networks that can contribute to the disease process. Typically SA is thought to be characterized by a Th2-low and Th17-high immunophenotype, accompanied by neutrophilic airway inflammation. However, Th2-mediated eosinophilic inflammation, as well as mixed Th1/Th17-mediated inflammation, is also described in SA. Thus, existing studies indicate that the immunophenotype of SA is diverse. This review attempts to summarize the interplay of different immune mediators and related mechanisms that are associated with airway inflammation and the immunobiology of SA.

Serum and sputum MMP-9/TIMP-1 in winter sports athletes and swimmers: relationships with airway function

INTRODUCTION

Skiers and swimmers present characteristics of airway inflammation and remodeling of the extracellular matrix similar to what is observed in mild asthma. We aimed to compare serum and sputum MMP-9/TIMP-1 levels, to assess the balance between airway fibrogenesis and inflammation process in both categories of athletes, and to observe its seasonal variations in winter sports athletes.

METHODS

We conducted a retrospective study. Winter sports athletes (n = 41), swimmers (n = 25) and healthy nonathletes (n = 10) had blood sampling, lung function measurement, skin prick tests, eucapnic voluntary hyperpnea challenge, methacholine inhalation test, and induced sputum analysis. Twelve winter sport athletes performed the tests during both summer and winter. Serum and sputum biomarkers were measured by ELISA.

RESULTS

No significant difference in serum or sputum MMP-9/TIMP-1 ratio was observed between groups, nor relationship with airway function or responsiveness. Serum MMP-9/TIMP-1 ratio was higher during the summer in winter sport athletes compared with winter season (median [Interquartile range]: 3.65 [2.47-4.03] ng.ml^-1 and 1.27 [0.97-1.62] ng.ml^-1, respectively, p = 0.005). Sputum MMP-9 correlated with methacholine PC₂₀ (r = 0.45, p = 0.019) and serum cc16/SP-D ratio (r=-0.47, p = 0.013).

CONCLUSION

MMP-9/TIMP-1 ratio in sputum or serum may fluctuate with training or environment but does not correlate with airway function or responsiveness in athletes.

Long noncoding RNA LINC-PINT retards the abnormal growth of airway smooth muscle cells via regulating the microRNA-26a-5p/PTEN axis in asthma

BACKGROUND

Asthma is a chronic respiratory disease worldwide. This study aimed to explore the functions of the long noncoding RNA LINC-PINT (LINC-PINT) in asthma and to determine its underlying molecular mechanisms.

METHODS

Rat asthma model was established with ovalbumin sensitization and challenge. The serum level of IgE, airway hyperresponsiveness (AHR), airway inflammation, and pathological changes of lung were evaluated. Airway smooth muscle cells (ASMCs) were stimulated with platelet-derived growth factor-BB (PDGF-BB) to mimic the asthma-like condition at cellular level. QRT-PCR was performed to detect the expression of LINC-PINT, microRNA-26a-5p (miR-26a-5p), and PTEN. MTT and transwell assays were performed to measure the viability and migration of ASMCs. The protein expression of airway remodelling marker MMP-1 and MMP-9 was measured by western blot. The interactions among LINC-PINT, miR-26a-5p, and PTEN were determined by dual-luciferase reporter assay.

RESULTS

The expression of LINC-PINT and PTEN was decreased, while miR-26a-5p expression was increased in PDGF-BB-stimulated ASMCs. In vivo, overexpression of LINC-PINT decreased the serum level of IgE, AHR, airway inflammation, and pathological changes of lung in asthma rat model. In vitro, up-regulation of LINC-PINT decreased the viability, migration, and MMP-1 and MMP-9 protein expression in PDGF-BB-stimulated ASMCs. Dual-luciferase reporter assay determined that LINC-PINT targeted miR-26a-5p, and miR-26a-5p targeted PTEN in ASMCs. Feedback approaches confirmed that miR-26a-5p up-regulation or PTEN down-regulation reversed the suppressive effect of LINC-PINT overexpression on the abnormal growth of ASMCs.

CONCLUSIONS

LINC-PINT overexpression retarded the abnormal growth of ASMCs by regulating the miR-26a-5p/PTEN axis, offering a potential therapeutic target for asthma.

Phenotypic Variations of Mild-to-Moderate Obstructive Pulmonary Diseases According to Airway Inflammation and Clinical Features

Purpose

Asthma and chronic obstructive pulmonary disease (COPD) are complex and heterogeneous inflammatory diseases. We sought to investigate distinct disease profiles based on clinical, cellular and molecular data from patients with mild-to-moderate obstructive pulmonary diseases.

Patients and Methods

Patients with mild-to-moderate allergic asthma (n=30) and COPD (n=30) were prospectively recruited. Clinical characteristics and induced sputum were collected. In total, 35 mediators were assessed in induced sputum. Logistic regression analysis was conducted to identify the optimal factors that were able to discriminate between asthma and COPD. Further, the data were explored using hierarchical clustering in order to discover and compare clusters of combined samples of asthma and COPD patients. Clinical parameters, cellular composition, and sputum mediators of asthma and COPD were assessed between and within obtained clusters.

Results

We found five clinical and biochemical variables, namely IL-6, IL-8, CCL4, FEV₁/VC ratio pre-bronchodilator (%), and sputum neutrophils (%) that differentiated asthma and COPD and were suitable for discrimination purposes. A combination of those variables yielded high sensitivity and specificity in the differentiation between asthma and COPD, although only FEV₁/VC ratio pre-bronchodilator (%) proven significant in the combined model. In cluster analysis, two main clusters were identified: cluster 1, asthma predominant with evidence of eosinophilic airway inflammation and low level of Th1 and Th2 cytokines; and cluster 2, COPD predominant with elevated levels of Th1 and Th2 mediators.

Conclusion

The inflammatory profile of sputum samples from patients with stable mild-to-moderate asthma and COPD is not disease specific, varies within the disease and might be similar between these diseases. This study highlights the need for phenotyping the mild-to-moderate stages according to their clinical and molecular features.

Triterpenoid compound betulin attenuates allergic airway inflammation by modulating antioxidants, inflammatory cytokines and tissue transglutaminase in ovalbumin-induced asthma mice model

OBJECTIVES

This study hypothesized that to analyse the anti-inflammatory effect of triterpenoid compound betulin in ovalbumin (OVA)-induced asthmatic mice.

METHODS

In this study, betulin was intraperitoneally administered in OVA-challenged and sensitized mice. The effect of betulin on inflammatory cells, lung function, reactive oxygen species (ROS) production, antioxidants status, oxidative stress markers, serum IgE level and inflammatory cytokines status in BALF was examined by enzyme-linked immunosorbent assay. The expression of tTG, TGF-β1, MMP-9 and TIMP-1 in lung tissue was scrutinized by RT-qPCR analysis, and the expression of TREM-1, p-IκB-α and NF-κBp65 proteins in lung tissue was examined by western blot analysis.

KEY FINDINGS

We found that the betulin treatment has effectively attenuated the proliferation of inflammatory cells, reduced the ROS generation, elevated the antioxidant enzymes and attenuated the level of oxidative markers in asthma induced mice. Moreover, reduced the level of serum IgE and pro-inflammatory cytokines, and increased the anti-inflammatory cytokine IFN-γ. Betulin treatment down-regulated the expression of MMP-9, tTG and TGF-β1 genes; moreover, betulin treatment effectively down-regulated the TREM-1, p-IκB-α and NF-κBp65 proteins level in lung.

CONCLUSION

Betulin exhibited effective anti-asthmatic activity by attenuating the accumulation of inflammatory cells, expression of tTG, TGF-β1 and MMP-9 genes in lung tissue.

Lrp1 Regulation of Pulmonary Function. Follow-Up of Human GWAS in Mice

Human genome-wide association studies (GWASs) have identified more than 270 loci associated with pulmonary function; however, follow-up studies to determine causal genes at these loci are few. SNPs in low-density lipoprotein receptor-related protein 1 (LRP1) are associated with human pulmonary function in GWASs. Using murine models, we investigated the effect of genetic disruption of the Lrp1 gene in smooth muscle cells on pulmonary function in naive animals and after exposure to bacterial LPS or house dust mite extract. Disruption of Lrp1 in smooth muscle cells leads to an increase in tissue resistance, elastance, and tissue elastance at baseline. Furthermore, disruption of Lrp1 in smooth muscle increases airway responsiveness as measured by increased total lung resistance and airway resistance after methacholine. Immune cell counts in BAL fluid were increased in animals with Lrp1 disruption. The difference in airway responsiveness by genotype observed in naive animals was not observed after LPS or house dust mite extract exposure. To further explore the mechanisms contributing to changes in pulmonary function, we identified several ligands dysregulated with Lrp1 disruption in smooth muscle cells. These data suggest that dysregulation of LRP1 in smooth muscle cells affects baseline pulmonary function and airway responsiveness and helps establish LRP1 as the causal gene at this GWAS locus.

Regulatory Effects of Nur77 on Airway Remodeling and ASMC Proliferation in House Dust Mite-Induced Asthma

Airway remodeling played a vital role in the development of asthma, and airway smooth muscle (ASM) mass was its hallmark. However, few strategies targeting ASM remodeling were developed in treating asthma. Nur77 was the transcription factor nuclear receptor involved in the pathogenesis of several lung diseases. Nur77 distribution and expression were determined in an HDM-mediated allergic asthma model. Its effect on airway hyperresponsiveness (AHR), chronic inflammation, and ASM remodeling in asthmatic mice was evaluated using a lentivirus-mediated shRNA. Possible mechanisms were explored by examining Nur77 actions and its underlying pathways in primary human AMC cells (ASMCs). In this study, we reported that Nur77 expression was mainly distributed along ASM and increased in lungs of HDM-challenged mice. Nur77 depletion by lentivirus-mediated shRNA ameliorated AHR, chronic inflammation, goblet cell hyperplasia, and airway remodeling in the asthmatic mouse model. By means of primary human ASMC, we discovered that Nur77 upregulation by HDM stimulation promoted cell proliferation and ROS production, as well as reduced antioxidant gene expression. These alterations might associate with MFN2/MAPK/AKT pathways. These findings broadened our understanding of airway remodeling and ASMC proliferation, which might provide a novel therapeutic target for asthma patients.

Targeting neutrophils in asthma: A therapeutic opportunity?

Suppression of airway inflammation with inhaled corticosteroids has been the key therapeutic approach for asthma for many years. Identification of inflammatory phenotypes in asthma has moreover led to important breakthroughs, e.g. with specific targeting of the IL-5 pathway as add-on treatment in difficult-to-treat eosinophilic asthma. However, the impact of interfering with the neutrophilic component in asthma is less documented and understood. This review provides an overview of established and recent insights with regard to the role of neutrophils in asthma, focusing on research in humans. We will describe the main drivers of neutrophilic responses in asthma, the heterogeneity in neutrophils and how they could contribute to asthma pathogenesis. Moreover we will describe findings from clinical trials, in which neutrophilic inflammation was targeted. It is clear that neutrophils are important actors in asthma development and play a role in exacerbations. However, more research is required to fully understand how modulation of neutrophil activity could lead to a significant benefit in asthma patients with airway neutrophilia.

Early identification of carotid vulnerable plaque in asymptomatic patients

BACKGROUND

This study was to explore the influencing factors of atherosclerotic plaque formation and stability in patients with asymptomatic carotid atherosclerotic plaques, so as to identify the vulnerable plaques at early stage, and then find high-risk group of cardio-cerebrovascular events for early clinical intervention to reduce related mortality and disability.

METHODS

A total of 302 enrolled patients with asymptomatic carotid atherosclerotic plaques were divided into 3 groups based on the results of carotid artery color Doppler ultrasound: atherosclerotic unstable plaque (UP) group, atherosclerotic stable plaque (SP) group, and control group without plaques. Serum markers were measured by ELISA. χ² test, t test, Pearson correlation analysis, and Logistic multivariate regression analysis were used in the analysis, and P < 0.05 was considered statistically significant.

RESULTS

It revealed that high MMP-9, LOX-1and YKL-40 were independent risk factors for unstable plaque formation. The area under the curve (AUC) of serum markers combined with MMP-9, LOX-1 and YKL-40 was 0.850, with sensitivity 87.67%, specificity 81.13%, and diagnostic accuracy 84.92%, which was significantly better than the individual diagnostic efficacy of other three factors. The accuracy rate of Crouse Plaque Score (CPS) in the diagnosis of vulnerable plaques was 61.90%, the 10-year ICVD diagnosis accuracy rate was 56.75%, and the diagnostic accuracy of serum markers was significantly better than CPS and 10-year ICVD.

CONCLUSION

Noninvasive cervical color Doppler ultrasound combined with serum markers MMP-9, LOX-1 and YKL-40 have significant early recognition effect on asymptomatic carotid vulnerable plaque patients.

Discovery of potential asthma targets based on the clinical efficacy of Traditional Chinese Medicine formulas

ETHNOPHARMACOLOGICAL RELEVANCE

Standard therapy for asthma, a highly heterogeneous disease, is primarily based on bronchodilators and immunosuppressive drugs, which confer short-term symptomatic relief but not a cure. It is difficult to discover novel bronchodilators, although potential new targets are emerging. Traditional Chinese Medicine (TCM) formulas have been used to treat asthma for more than 2000 years, forming the basis for representative asthma treatments.

AIM OF THE STUDY

Based on the efficacy of TCM formulas, anti-asthmatic herbal compounds bind proteins are potential targets for asthma therapy. This analysis will provide new drug targets and discovery strategies for asthma therapy.

MATERIALS AND METHODS

A list of candidate herbs for asthma was selected from the classical formulas (CFs) of TCM for the treatment of wheezing or dyspnea recorded in Treatise on Cold Damage and Miscellaneous Diseases (TCDMD) and from modern herbal formulas identified in the SAPHRON TCM Database using the keywords "wheezing" or "dyspnea". Compounds in the selected herbs and compounds that directly bind target proteins were acquired by searching the Herbal Ingredients' Targets Database (HITD), TCM Data Bank (TCMDB) and TCM Integrated Database (TCMID). Therapeutic targets of conventional medicine (CM) for asthma were collected by searching Therapeutic Target Database (TTD), DrugBank and PubMed as supplements. Finally, the enriched gene ontology (GO) terms of the targets were obtained using the Database for Annotation Visualization and Integrated Discovery (DAVID) and protein-protein interactions (PPI) networks were constructed using Search Tool for the Retrieval of Interacting Genes/Proteins (STRING). The effects of two selected TCM compounds, kaempferol and ginkgolide A, on cellular resistance in human airway smooth muscle cells (ASMCs) and pulmonary resistance in a mouse model were investigated.

RESULTS

The list of 32 candidate herbs for asthma was selected from 10 CFs for the treatment of wheezing or dyspnea recorded in TCDMD and 1037 modern herbal formulas obtained from the SAPHRON TCM Database. A total of 130 compounds from the 32 selected herbs and 68 herbal compounds directly bind target proteins were acquired from HITD and TCMDB. Eighty-eight therapeutic targets of CM for asthma were collected by searching TTD and PubMed as supplements. DAVID and STRING analyses showed targets of TCM formulas are primarily related to cytochrome P450 (CYP) family, transient receptor potential (TRP) channels, matrix metalloproteinases (MMPs) and ribosomal protein. Both TCM formulas and CM act on the same types of targets or signaling pathways, such as G protein-coupled receptors (GPCRs), steroid hormone receptors (SHRs), and JAK-STAT signaling pathway. The proteins directly targeted by herbal compounds, TRPM8, TRPA1, TRPV3, CYP1B1, CYP2B6, CYP1A2, CYP3A4, CYP1A1, PPARA, PPARD, NR1I2, MMP1, MMP2, ESR1, ESR2, RPLP0, RPLP1 and RPLP2, are potential targets for asthma therapy. In vitro results showed kaempferol (1 × 10^-2 mM) and ginkgolide A (1 × 10^-5 mM) significantly increased the cell index (P < 0.05 vs. histamine, n = 3) and therefore relaxed human ASMCs. In vivo results showed kaempferol (145 μg/kg) and ginkgolide A (205 μg/kg) significantly reduced pulmonary resistance (P < 0.05 vs. methacholine, n = 6).

CONCLUSION

Potential target discovery for asthma treatment based on the clinical effectiveness of TCM is a feasible strategy.

Needs for Systems Approaches to Better Treat Individuals With Severe Asthma: Predicting Phenotypes and Responses to Treatments

Asthma is a frequent heterogeneous multifactorial chronic disease whose severe forms remain largely uncontrolled despite the availability of many drugs and educational therapy. Several phenotypes and endotypes of severe asthma have been described over the last two decades. Typical type-2-immunity-driven asthma remains the most frequent phenotype, and several targeted therapies have been developed and are now available. On the contrary, non-type-2 immunity-driven severe asthma is less understood and still requires efficient innovative therapies. A personalized approach would allow improving asthma control with the help of robust biomarkers able to predict phenotypes/endotypes, exacerbations, response to targeted treatments and, in the future, possible curative options. Some data from large multicenter cohorts have emerged in recent years, especially in transcriptomics. These data have to be integrated and reproduced longitudinally to provide a systems approach for asthma care. In this focused review, the needs for such an approach and the available data will be reviewed as well as the next steps for achieving personalized medicine in asthma.

Chlamydia pneumoniae Influence on Cytokine Production in Steroid-Resistant and Steroid-Sensitive Asthmatics

Medications for asthma management consisting of inhaled corticosteroids act by controlling symptoms. However, some patients do not respond to steroid treatment due to immunological factors at the cytokine level. Chlamydia pneumoniae (C. pneumoniae) infection is strongly implicated in asthma pathogenesis, causing altered immune responses. We investigated the association of C. pneumoniae serostatus with the production of certain cytokines by peripheral blood mononuclear cells (PBMCs) of steroid-resistant and -sensitive asthmatic patients. Our most important findings are the following: In the case of C. pneumoniae seropositive patients we detected pronounced spontaneous interleukin (IL)-10 secretion and, in the case of steroid-resistant patients, IL-10 secretion was at a significantly higher level as compared with in-sensitive patients (p < 0.01). Furthermore, steroid-resistant seropositive patients produced a significantly higher level of IL-10 spontaneously and under antigen stimulation as compared with steroid-resistant seronegative individuals (p < 0.05). Concerning spontaneous TNF-α secretion by C. pneumoniae seropositive asthmatics, we observed that steroid-resistant patients produced significantly more of this cytokine than steroid-sensitive patients. In the steroid-resistant patients’ sera, a remarkably high MMP-9 concentration was associated with C. pneumoniae seronegativity. Our study revealed that the differences in the cytokine production in steroid-sensitive and -resistant asthmatic patients can be influenced by their C. pneumoniae serostatus.

Imperatorin alleviates ROS-mediated airway remodeling by targeting the Nrf2/HO-1 signaling pathway

In this study, we investigated the role and mechanism of imperatorin (IMP) in chronic inflammation and airway remodeling. The levels of TNF-α, IL-1β, IL-6, IL-8, VEGF, α-SMA, and ROS were detected by ELISA, immunohistochemistry (IHC), immunofluorescence, and Western blot. In addition, we evaluated the effect of IMP on MAPK, PI3K/Akt, NF-κB, and Nrf2/HO-1 signaling pathways. IMP treatment obviously attenuated the production of inflammatory cytokines and inflammatory cells in bronchoalveolar lavage fluid of OVA-induced airway remodeling model. Meanwhile, it significantly inhibited inflammatory cell infiltration, goblet cell hyperplasia, collagen deposition, VEGF production, α-SMA, and ROS expression. Our study has shown that IMP could regulate the signaling pathways including MAPK, PI3K/Akt, NF-κB, and Nrf2/HO-1 to release the inflammatory responses. IMP might attenuate airway remodeling by the down-regulation of Nrf2/HO-1/ROS/PI3K/Akt, Nrf2/HO-1/ROS/MAPK, and Nrf2/HO-1/ROS/NF-κB signaling pathways.

Fibrinogen Is a Specific Trigger for Cytolytic Eosinophil Degranulation

In inflamed human tissues, we often find intact eosinophilic granules, but not eosinophils themselves. Eosinophils, tissue-dwelling granulocytes with several homeostatic roles, have a surprising association with fibrinogen and tissue remodeling. Fibrinogen is a complex glycoprotein with regulatory roles in hemostasis, tumor development, wound healing, and atherogenesis. Despite its significance, the functional link between eosinophils and fibrinogen is not understood. We tested IL-5-primed mouse bone marrow-derived and human blood-sorted eosinophil activity against FITC-linked fibrinogen substrates. The interactions between these scaffolds and adhering eosinophils were quantified using three-dimensional laser spectral, confocal, and transmission electron microscopy. Eosinophils were labeled with major basic protein (MBP) Ab to visualize granules and assessed by flow cytometry. Both mouse and human eosinophils showed firm adhesion and degraded up to 27 ± 3.1% of the substrate area. This co-occurred with active MBP-positive granule release and the expression of integrin CD11b. Mass spectrometry analysis of fibrinogen proteolytic reactions detected the presence of eosinophil peroxidase, MBP, and fibrin α-, β-, and γ-chains. Eosinophil activity was adhesion dependent, as a blocking Ab against CD11b significantly reduced adhesion, degranulation, and fibrinogenolysis. Although adhered, eosinophils exhibited no proteolytic activity on collagen matrices. Cytolytic degranulation was defined by loss of membrane integrity, cell death, and presence of cell-free granules. From transmission electron microscopy images, we observed only fibrinogen-exposed eosinophils undergoing this process. To our knowledge, this is the first report to show that fibrinogen is a specific trigger for cytolytic eosinophil degranulation with implications in human disease.

Increased Ratio of Matrix Metalloproteinase-9 (MMP-9)/Tissue Inhibitor Metalloproteinase-1 from Alveolar Macrophages in Chronic Asthma with a Fast Decline in FEV1 at 5-Year Follow-up

Chronic asthma is associated with progressive airway remodeling, which may contribute to declining lung function. An increase in matrix metalloproteinases-9 (MMP-9)/tissue inhibitor metalloproteinase-1 (TIMP-1) may indicate airway inflammation and bronchial injury. Bronchial biopsy specimens and alveolar macrophages (AMs) were obtained from patients with asthma under regular treatment with inhaled corticosteroids or combination therapy and normal subjects (n = 10). Asthmatics included those with a slow forced expiratory volume in one second (FEV₁) decline (<30 mL/year, n = 13) and those with a fast FEV₁ decline (≥30 mL/year, n = 8) in 5-year follow-up. Immunostaining expression of MMP-9 and TIMP-1 was detected in airway tissues. MMP-9 and TIMP-1 was measured from AMs cultured for 24 h. After the 5-year treatment, the methacholine airway hyperresponsiveness of the slow FEV₁ decline group was decreased, but that of the fast FEV₁ decline group was increased (PC₂₀, provocative concentration causing a 20% decrease in FEV₁, 3.12 ± 1.10 to 1.14 ± 0.34 mg/dL, p < 0.05). AMs of asthma with a fast FEV₁ decline released a higher level of MMP-9 (8.52 ± 3.53 pg/mL, p < 0.05) than those of a slow FEV₁ decline (0.99 ± 0.20 pg/mL). The MMP-9/TIMP ratio in the fast FEV₁ decline group (0.089 ± 0.032) was higher than that of the slow FEV₁ decline group (0.007 ± 0.001, p < 0.01). The annual FEV₁ decline in 5 years was proportional to the level of MMP-9 (r = 57, p < 0.01) and MMP-9/TIMP-1 ratio (r = 0.58, p < 0.01). The airways of asthma with greater yearly decline in FEV₁ showed an increased thickness of submucosa and strong expression of MMP-9. An increase in MMP-9 and MMP-9/TIMP-1 in airways or AMs could be indicators of chronic airway inflammation and contribute to a greater decline in lung function of patients with chronic asthma.

Methylation status of ORMDL3 regulates cytokine production and p-ERK/MMP9 pathway expression

Orosomucoid like-3 (ORMDL3) has been identified to be associated with the development of asthma according to previous studies. However, the definite role of ORMDL3 in the pathogenesis of asthma remains unclear. In this study, we found ORMDL3 was highly expressed in PBMC specimens from childhood asthma patients. Cytokines production and p-ERK/MMP-9 pathway expression was also increased in childhood asthma patients compared with controls. In addition, ORMDL3 overexpression induced IL-6 and IL-8 release and activated p-ERK/MMP-9 pathway in vitro. Increased ORMDL3 expression was observed after treated with 5-Aza-CdR. 5-Aza-CdR decreased the percentage of the CpG island in the ORMDL3 promoter region and increased its promoter activity. In addition, 5-Aza-CdR significantly increased IL-6 and IL-8 levels in NHBE cells while there was no obvious alteration after knocking down ORMDL3. Knockdown of ORMDL3 also significantly decreased the expression of p-ERK/MMP-9 pathway in the presence or absence of 5-Aza-CdR. In conclusion, our study provided novel evidence for the association between ORMDL3 and asthma-associated cytokines. Moreover, DNA methylation plays an important role in ORMDL3-mediated increased IL-6 and IL-8 levels and p-ERK/MMP-9 pathway expression.

Atorvastatin has a protective effect in a mouse model of bronchial asthma through regulating tissue transglutaminase and triggering receptor expressed on myeloid cells-1 expression

Airway remodeling in asthma contributes to airway hyperreactivity, loss of lung function and persistent symptoms. Current therapies do not adequately treat the structural airway changes associated with asthma. Statin drugs have improved respiratory health and their therapeutic potential in asthma has been tested in clinical trials. However, the mechanism of action of statins in this context has remained elusive. The present study hypothesized that atorvastatin treatment of ovalbumin-exposed mice attenuates early features of airway remodeling via a mevalonate-dependent mechanism. BALB/c mice were sensitized with ovalbumin and atorvastatin was delivered via oral gavage prior to each ovalbumin exposure. Reverse transcription-semi-quantitative polymerase chain reaction (RT-semi-qPCR), ELISA and western blot analysis were used to assess the expression of a number of relevant genes, including tissue transglutaminase (tTG), triggering receptor expressed on myeloid cells (TREM)-1, nuclear factor erythroid 2-related factor (Nrf) 2, hypoxia-inducible factor (HIF)-1α, transforming growth factor (TGF)-β1, matrix metalloproteinase (MMP)-9 and tissue inhibitors of metalloproteinases (TIMP)-1 in lung tissue. α-Smooth muscle actin (α-SMA) activity was measured by immunohistochemistry. Airway hyperresponsiveness, lung collagen deposition, airway wall area, airway smooth muscle thickness and lung pathology were also assessed. Atorvastatin treatment led to downregulation of tTG and TREM-1 expression in lung tissue after ovalbumin sensitization, blocked the activity of MMP-9, vascular endothelial growth factor, nuclear factor-κB p65, α-SMA, HIF-α and TGF-β1 and up-regulated Nrf2 expression. Furthermore, the number of lymphocytes and eosinophils in the atorvastatin group was significantly lower than that in the control group. In addition, airway hyperresponsiveness, lung collagen deposition, airway wall area, airway smooth muscle thickness and pathological changes in the lung were significantly decreased in the atorvastatin group, and tumor necrosis factor-α, interleukin (IL)-8, IL-13 and IL-17 in serum were significantly decreased. Histological results demonstrated the attenuating effect of atorvastatin on ovalbumin-induced airway remodeling in asthma. In conclusion, the present study indicated that atorvastatin significantly alleviated ovalbumin-induced airway remodeling in asthma by downregulating tTG and TREM-1 expression. The marked protective effects of atorvastatin suggest its therapeutic potential in ovalbumin-induced airway remodeling in asthma treatment.

Brain-derived neurotrophic factor and airway fibrosis in asthma

Airway remodeling in asthma driven by inflammation involves proliferation of epithelial cells and airway smooth muscle (ASM), as well as enhanced extracellular matrix (ECM) generation and deposition, i.e., fibrosis. Accordingly, understanding profibrotic mechanisms is important for developing novel therapeutic strategies in asthma. Recent studies, including our own, have suggested a role for locally produced growth factors such as brain-derived neurotrophic factor (BDNF) in mediating and modulating inflammation effects. In this study, we explored the profibrotic influence of BDNF in the context of asthma by examining expression, activity, and deposition of ECM proteins in primary ASM cells isolated from asthmatic vs. nonasthmatic patients. Basal BDNF expression and secretion, and levels of the high-affinity BDNF receptor TrkB, were higher in asthmatic ASM. Exogenous BDNF significantly increased ECM production and deposition, especially of collagen-1 and collagen-3 (less so fibronectin) and the activity of matrix metalloproteinases (MMP-2, MMP-9). Exposure to the proinflammatory cytokine TNFα significantly increased BDNF secretion, particularly in asthmatic ASM, whereas no significant changes were observed with IL-13. Chelation of BDNF using TrkB-Fc reversed TNFα-induced increase in ECM deposition. Conditioned media from asthmatic ASM enhanced ECM generation in nonasthmatic ASM, which was blunted by BDNF chelation. Inflammation-induced changes in MMP-2, MMP-9, and tissue inhibitor metalloproteinases (TIMP-1, TIMP-2) were reversed in the presence of TrkB-Fc. These novel data suggest ASM as an inflammation-sensitive source of BDNF within human airways, with autocrine effects on fibrosis relevant to asthma.

Matrix metalloproteinases and airway remodeling and function in primary ciliary dyskinesia

BACKGROUND

The balance between matrix metalloproteinases (MMPs) and their tissue inhibitors (TIMPs) is important in the regulation of airway damage.

OBJECTIVE

To evaluate whether they are important in the pathophysiology of primary and secondary ciliary dyskinesia (PCD, SCD).

METHODS

We measured sputum bacteriology, lung CT changes, MMPs, TIMPs and lung function in 86 patients (51 PCD, 35 SCD) in a cross-sectional study; the 10 controls studied did not have HRCT or sputum cultures. MMPs, TIMPs and lung function were evaluated longitudinally for up to one year in 38 PCD patients.

RESULTS

At baseline, there were no differences in MMPs, TIMPs and MMPs/TIMPs, between PCD and SCD but lower levels were found in controls. There was an association between poorer lung function with increasing levels of MMPs in PCD, while in SCD only MMP-9/TIMP-1 values correlated with FRC z-scores. Levels of MMPs and TIMPs significantly correlated with severity HRCT changes. Longitudinally, there were significant correlations between slope of changes in spirometric parameters and slope of change in sputum MMPs in PCD patients.

CONCLUSIONS

In conclusion, we report for the first time that increased MMPs are associated with worse airway damage in PCD and SCD, and thus are potential therapeutic targets.

Severe Asthma: Have We Made Progress?

Tremendous efforts have been invested in research to (1) discover risk factors, biomarkers, and clinical characteristics; (2) understand the pathophysiology and treatment response variability in severe asthma; and (3) design new therapies. However, to combat severe asthma, many questions concerning the pathogenesis of severe asthma, including its natural history, genetic and environmental risk factors, and disease mechanisms, must be answered. In this article we highlight some of the major discoveries concerning the pathogenesis of severe asthma and its therapeutic development. We conclude that discoveries on numerous fronts of severe asthma, from disease heterogeneity, features of airway remodeling, cytokine mediators and signaling pathways underlying disease pathogenesis, disease mechanisms, potential biomarkers, to new therapeutic targets, demonstrate that progress has been made in understanding and developing more effective treatments for this difficult-to-treat disease.

Herbal Medicine Cordyceps sinensis Improves Health-Related Quality of Life in Moderate-to-Severe Asthma

Moderate-to-severe asthma has a substantial impact on the health-related quality of life (HR-QOL) of the patients. Cordyceps sinensis is a traditional Chinese medicine that is evaluated clinically for the treatment of many diseases, such as chronic allograft nephropathy, diabetic kidney disease, and lung fibrosis. In order to investigate the effects of Cordyceps sinensis on patients with moderate-to-severe persistent asthma, 120 subjects were randomized to receive Corbin capsule containing Cordyceps sinensis for 3 months (treatment group, n = 60), whereas the control group (n = 60) did not receive treatment with Corbin capsule. Inhaled corticosteroid and as-needed β-agonists were used in the treatment of both groups. HR-QOL was measured with the Juniper's Asthma Quality of Life Questionnaire (AQLQ). The incidence of asthma exacerbation, pulmonary function testing, and serum measurements of inflammatory mediators were also evaluated. The results showed that the treatment group indicated a significant increase in AQLQ scores and lung function compared with the control group. The expression levels of the inflammation markers IgE, ICAM-1, IL-4, and MMP-9 in the serum were decreased and IgG increased in the treatment group compared with the control group. Therefore, the conclusion was reached that a formulation of Cordyceps sinensis improved the HR-QOL, asthma symptoms, lung function, and inflammatory profile of the patients with moderate-to-severe asthma. This trial is registered with ChiCTR-IPC-16008730.

Relation of dietary inorganic arsenic to serum matrix metalloproteinase-9 (MMP-9) at different threshold concentrations of tap water arsenic

Arsenic (As) exposure is associated with cancer, lung and cardiovascular disease, yet the mechanisms involved are not clearly understood. Elevated matrix metalloproteinase-9 (MMP-9) levels are also associated with these diseases, as well as with exposure to water As. Our objective was to evaluate the effects of dietary components of inorganic As (iAs) intake on serum MMP-9 concentration at differing levels of tap water As. In a cross-sectional study of 214 adults, dietary iAs intake was estimated from 24-h dietary recall interviews using published iAs residue data; drinking and cooking water As intake from water samples and consumption data. Aggregate iAs intake (food plus water) was associated with elevated serum MMP-9 in mixed model regression, with and without adjustment for covariates. In models stratified by tap water As, aggregate intake was a significant positive predictor of serum MMP-9 in subjects exposed to water As≤10 μg/l. Inorganic As from food alone was associated with serum MMP-9 in subjects exposed to tap water As≤3 μg/l. Exposure to iAs from food and water combined, in areas where tap water As concentration is ≤10 μg/l, may contribute to As-induced changes in a biomarker associated with toxicity.

Inhaled corticosteroids do not reduce initial high activity of matrix metalloproteinase (MMP)-9 in exhaled breath condensates of children with asthma exacerbation: a proof of concept study

Inhaled corticosteroids (ICS) are the key component of asthma treatment. However, it is unclear whether they could control the activity and level of matrix metalloproteinase (MMP)-9, which is an important factor in asthma-associated inflammation and airway remodeling. Therefore, the aim of this proof of concept study was to analyze the influence of increased doses of ICS on MMP-9 in exhaled breath condensates (EBC) of patients with allergic asthma exacerbation. Apart from MMP-9, the assessment concerned selected inflammation markers – exhaled nitric oxide (eNO) and cytokines (IL-8 and TNF).

The study involved a small group (n = 4) of individuals with asthma exacerbation. The intervention concerned increased doses of ICS with β-mimetics for 4 weeks. In addition to clinical evaluation, eNO measurements and EBC collections were done before and after 4 weeks of intense ICS treatment. The biochemical assessment of EBC concerned MMP-9, IL-8 and TNF. The data were compared to results of healthy controls (n = 6).

The initial levels of eNO, MMP-9 and TNF in EBC were higher in the asthma group than in controls. In all subjects IL-8 levels were below the detection limit. After 4 weeks of ICS treatment in all patients we observed improvement of clinical and laboratory parameters. Interestingly, despite reduction of eNO and TNF, the activity of MMP-9/EBC remained on the initial level.

Practical relevance of our results is limited by a small group. Nevertheless, our data suggest that ICS, although sufficient to control symptoms and inflammatory markers, may be ineffective to reduce MMP-9/EBC activity in asthma exacerbation and, possibly, airway remodeling.

Polymorphic Variants 279R and 668Q Augment Activity of Matrix Metalloproteinase-9 in Breath Condensates of Children with Asthma

Matrix metalloproteinase (MMP)-9 is involved in pathophysiology of asthma, mainly asthma-associated airway remodeling. Exhaled breath condensates (EBC) of asthmatics contain increased amounts of MMP-9 with activity higher, than in healthy controls. The increased activity of MMP-9 may originate from its excessive production and activation, but may also result from variations in MMP-9 structure, which are determined by single nucleotide polymorphisms (SNPs). In this pilot study we aimed to assess the possible influence of two functional MMP-9 polymorphisms, Q279R and R668Q, on enzymatic activity of MMP-9, measured in EBC of asthmatic children. The concentration and activity of MMP-9 were analyzed in EBC of 20 children with allergic asthma using specific standard ELISA and novel immunoenzymatic activity assay. The SNPs of MMP-9 were assessed using real-time PCR-based genotyping test. We have found that MMP-9 concentration in breath condensates of children with stable asthma was slightly higher in ELISA, than in the activity assay. Moreover, these results and activity-to-amount ratio have revealed some relationship with a presence of specific 279R and/or 668Q MMP-9 gene variants. Our observation suggests that at least in some patients MMP-9 hyperactivity may result from genetic predisposition, determined by polymorphic variants of MMP-9 gene. Moreover, it supports previous reports postulating significance of MMP-9 in pathogenesis of asthma. However, this issue still requires further studies.

Downregulation of matrix metalloproteinase‑19 induced by respiratory syncytial viral infection affects the interaction between epithelial cells and fibroblasts

The present study was designed to examine the expression and function of matrix metalloproteinase-19 (MMP-19), which is downregulated following respiratory syncytial virus (RSV) infection. The diverse expression levels of MMP were examined using a designed cDNA expression array. The expression and secretion of MMP-19 was examined using reverse transcription-quantitative polymerase chain reaction (RT-qPCR) analysis and ELISA, respectively. The proliferation of epithelial cells and lung fibroblasts were examined using flow cytometry. The epithelial-mesenchymal transition (EMT) was also examined by performing western blot and RT-qPCR analyses. The results of the cDNA assay showed that infection with RSV resulted in the abnormal expression of certain metalloproteinases. Among these, the expression of MMP-19 decreased 3 and 7 days following infection. By using flow cytometric, western blot and RT-qPCR analyses, the present study demonstrated that the downregulation of MMP-19 inhibited the proliferation of epithelial cells, promoted the EMT and induced the proliferation of lung fibroblasts. Taken together, the findings of the present study suggested that the downregulation of MMP-19 following RSV infection may be associated with the development of airway hyper-responsiveness.

Galangin attenuates airway remodelling by inhibiting TGF-β1-mediated ROS generation and MAPK/Akt phosphorylation in asthma

Galangin, a natural flavonol, has attracted much attention for its potential anti-inflammatory properties. However, its role in the regulation of airway remodelling in asthma has not been explored. The present study aimed to elucidate the effects of galangin on chronic inflammation and airway remodelling and to investigate the underlying mechanisms both in vivo and in vitro. Ovalbumin (OVA)-sensitised mice were administered with galangin 30 min before challenge. Our results showed that severe inflammatory responses and airway remodelling occurred in OVA-induced mice. Treatment with galangin markedly attenuated the leakage of inflammatory cells into bronchoalveolar lavage fluid (BALF) and decreased the level of OVA-specific IgE in serum. Galangin significantly inhibited goblet cell hyperplasia, collagen deposition and α-SMA expression. Lowered level of TGF-β1 and suppressed expression of VEGF and MMP-9 were observed in BALF or lung tissue, implying that galangin has an optimal anti-remodelling effect in vivo. Consistently, the TGF-β1-induced proliferation of airway smooth muscle cells was reduced by galangin in vitro, which might be due to the alleviation of ROS levels and inhibition of MAPK pathway. Taken together, the present findings highlight a novel role for galangin as a promising anti-remodelling agent in asthma, which likely involves the TGF-β1-ROS-MAPK pathway.

Biological and genetic markers in occupational asthma

Occupational asthma (OA) is a complex disease that is often hard to diagnose due to difficulties in detecting relevant exposure, along with inherent differences in disease susceptibility. Numerous studies have attempted to identify relevant biological and genetic markers for OA and to devise tools capable of detecting exposure to the causative agent. Immunological markers, including skin prick test reactivity and specific IgE and IgG antibodies can be used to detect high-molecular-weight allergens in cases of baker's asthma. For OA induced by low-molecular-weight agents, such as isocyanate, potential biomarkers include serum-specific IgE and IgG antibodies to isocyanate-HSA conjugate and IgG to cytokeratin 19 and transglutaminase-2. For protein-based markers, ferritin/transferrin and vitamin D-binding protein levels have been suggested for isocyanate-OA. Genetic markers of susceptibility to isocyanate-OA include human leukocyte antigen and CTNNA3. Further investigations will be needed to identify better biomarkers for OA, which may be used to inform clinical decision.

Prolonged Treatment with Inhaled Corticosteroids does not Normalize High Activity of Matrix Metalloproteinase-9 in Exhaled Breath Condensates of Children with Asthma

The airway remodeling in asthma is associated with increased amount of matrix metalloproteinase (MMP)-9. High levels of MMP-9 were found in mucosal biopsies, sputum and in exhaled breath condensates (EBC) of asthma patients. However, there are no data concerning real in vivo activity. Inhaled corticosteroids are effective in asthma control, but it is unclear, whether they only attenuate inflammation, or also protect against progressive remodeling of respiratory tract. Therefore, the aim of the study was to assess the amount and activity of MMP-9 in context of pro-inflammatory cytokines (IL-6, IL-8 and tumor necrosis factor, TNF), measured in EBC of asthma-suffering children, treated with inhaled steroids. The study involved 27 children with asthma, continuously treated with inhaled fluticasone propionate, and 22 healthy controls. In addition to routine clinical screening, the selected cytokines in EBC were analyzed using Ultrasensitive ELISA, whereas activity of MMP-9 was assessed using a novel immunozymography method. Despite chronic treatment with inhaled steroids mean MMP-9/EBC activity in asthma group was significantly higher than in healthy controls. Moreover, high MMP-9/EBC in asthma-suffering children significantly correlated with IgE serum levels. The IL-6 and IL-8 concentration was below the detection limit in all EBC samples. TNF/EBC levels were similar in both, asthma and healthy children. We hypothesize that MMP-9 hyperactivity in asthma may be closely related to high IgE serum levels. Our results suggest that inhaled steroids may be ineffective to prevent asthma-associated airway remodeling. Finally, we emphasize the necessity of further research focused on MMP-9 inhibition in asthma treatment.