High resolution computed tomographic assessment of airway wall thickness in chronic asthma: reproducibility and relationship with lung function and severity

Computed tomography in severe asthma assessment: a systematic review

OBJECTIVE

Chest computed tomography (CT) is usually performed in patients with severe asthma (SA) to exclude concomitant conditions related to poor clinical control. Despite the growing evidence regarding the utility of CT in the characterization of morphological abnormalities and airway remodeling, its role in SA assessment is still largely unexplored. The aim of our systematic review was to evaluate published data investigating the role of chest CT in patients with SA.

DATA SOURCES

The systematic search was conducted on the Medline database through the Pubmed search engine.

STUDY SELECTIONS

A total of 53 studies has been included.

RESULTS

Quantitative CT (qCT) parameters generally differ between SA patients compared to mild to moderate asthmatic patients or healthy controls and are related to functional decline. CT parameters allow to identify image-based clusters reflecting remodeling patterns and/or air trapping features. The detection of mucus plugs is more frequent in severe eosinophilic asthma, and it is related to marked airway obstruction and ventilation defects. Benralizumab treatment appears to reduce or vanish mucus plugging. Most studies regarding CT and bronchial thermoplasty (BT) detect the usefulness of this investigation in predicting treatment response. Lastly, conflicting results surround the relation between chest CT and SA assessment in children due to also the scarcity of studies focusing on pediatric population.

CONCLUSIONS

The role of CT scans in SA is still debated. Most studies focus on the identification of CT-derived disease clusters while studies primarily evaluating the predicting role of CT scan to different biologics are lacking and could represent an interesting research area.

Bronchial wall T2w MRI signal as a new imaging biomarker of severe asthma

OBJECTIVES

Severe asthma patients are prone to severe exacerbations with a need of hospital admission increasing the economic burden on healthcare systems. T2w lung MRI was found to be useful in the assessment of bronchial inflammation. The main goal of this study is to compare quantitative MRI T2 signal bronchial intensity between patients with severe and non-severe asthma.

METHODS

This is an ancillary study of a prospective single-center study (NCT03089346). We assessed the mean T2 intensity MRI signal of the bronchial wall area (BrWall_T2-MIS) in 15 severe and 15 age and sex-matched non-severe asthmatic patients. They also have had pulmonary function tests (PFTs), fractional exhaled nitric oxide (FeNO) and blood eosinophils count (Eos). Comparisons between the two groups were performed using Student's t-test. Correlations were assessed using Pearson coefficients. Reproducibility was assessed using intraclass correlation coefficient and Bland-Altman analysis.

RESULTS

BrWall_T2-MIS was higher in severe than in non-severe asthma patients (74 ± 12 vs 49 ± 14; respectively p < 0.001). BrWall_T2-MIS showed a moderate inverse correlation with PFTs in the whole cohort (r = -0.54, r = -0.44 for FEV1(%pred) and FEV1/FVC respectively, p ≤ 0.01) and in the severe asthma group (r = -0.53, r = -0.44 for FEV1(%pred) and FEV1/FVC respectively, p ≤ 0.01). Eos was moderately correlated with BrWall_T2-MIS in severe asthma group (r = 0.52, p = 0.047). Reproducibility was almost perfect with ICC = 0.99 and mean difference in Bland-Altman analysis of -0.15 [95% CI = -0.48-0.16].

CONCLUSION

Quantification of bronchial wall T2w signal intensity appears to be able to differentiate severe from non-severe asthma and correlates with obstructive PFTs' parameters and inflammatory markers in severe asthma.

CRITICAL RELEVANCE STATEMENT

The development of non-ionizing imaging biomarkers could play an essential role in the management of patients with severe asthma in the current era of biological therapies.

KEY POINTS

Severe asthma exhibits severe exacerbations with a high burden on healthcare systems. T2w bronchial wall signal intensity is related to inflammatory biomarker in severe asthma. T2w MRI may represent a non-invasive tool to follow up severe asthma patients.

Airway Remodeling in Asthma: Mechanisms, Diagnosis, Treatment, and Future Directions

Airway remodeling (AR) with chronic inflammation, are key features in asthma pathogenesis. AR characterized by structural changes in the bronchial wall is associated with a specific asthma phenotype with poor clinical outcomes, impaired lung function and reduced treatment response. Most studies focus on the role of inflammation, while understanding the mechanisms driving AR is crucial for developing disease-modifying therapeutic strategies. This review paper summarizes current knowledge on the mechanisms underlying AR, diagnostic tools, and therapeutic approaches. Mechanisms explored include the role of the resident cells and the inflammatory cascade in AR. Diagnostic methods such as bronchial biopsy, lung function testing, imaging, and possible biomarkers are described. The effectiveness on AR of different treatments of asthma including corticosteroids, leukotriene modifiers, bronchodilators, macrolides, biologics, and bronchial thermoplasty is discussed, as well as other possible therapeutic options. AR poses a significant challenge in asthma management, contributing to disease severity and treatment resistance. Current therapeutic approaches target mostly airway inflammation rather than smooth muscle cell dysfunction and showed limited benefits on AR. Future research should focus more on investigating the mechanisms involved in AR to identify novel therapeutic targets and to develop new effective treatments able to prevent irreversible structural changes and improve long-term asthma outcomes.

Artificial intelligence in COPD CT images: identification, staging, and quantitation

Chronic obstructive pulmonary disease (COPD) stands as a significant global health challenge, with its intricate pathophysiological manifestations often demanding advanced diagnostic strategies. The recent applications of artificial intelligence (AI) within the realm of medical imaging, especially in computed tomography, present a promising avenue for transformative changes in COPD diagnosis and management. This review delves deep into the capabilities and advancements of AI, particularly focusing on machine learning and deep learning, and their applications in COPD identification, staging, and imaging phenotypes. Emphasis is laid on the AI-powered insights into emphysema, airway dynamics, and vascular structures. The challenges linked with data intricacies and the integration of AI in the clinical landscape are discussed. Lastly, the review casts a forward-looking perspective, highlighting emerging innovations in AI for COPD imaging and the potential of interdisciplinary collaborations, hinting at a future where AI doesn't just support but pioneers breakthroughs in COPD care. Through this review, we aim to provide a comprehensive understanding of the current state and future potential of AI in shaping the landscape of COPD diagnosis and management.

The New Paradigm: The Role of Proteins and Triggers in the Evolution of Allergic Asthma

Epithelial barrier damage plays a central role in the development and maintenance of allergic inflammation. Rises in the epithelial barrier permeability of airways alter tissue homeostasis and allow the penetration of allergens and other external agents. Different factors contribute to barrier impairment, such as eosinophilic infiltration and allergen protease action-eosinophilic cationic proteins' effects and allergens' proteolytic activity both contribute significantly to epithelial damage. In the airways, allergen proteases degrade the epithelial junctional proteins, allowing allergen penetration and its uptake by dendritic cells. This increase in allergen-immune system interaction induces the release of alarmins and the activation of type 2 inflammatory pathways, causing or worsening the main symptoms at the skin, bowel, and respiratory levels. We aim to highlight the molecular mechanisms underlying allergenic protease-induced epithelial barrier damage and the role of immune response in allergic asthma onset, maintenance, and progression. Moreover, we will explore potential clinical and radiological biomarkers of airway remodeling in allergic asthma patients.

Pulmonary MRI with hyperpolarized xenon-129 demonstrates novel alterations in gas transfer across the air-blood barrier in asthma

BACKGROUND

Individuals with asthma can vary widely in clinical presentation, severity, and pathobiology. Hyperpolarized xenon-129 (Xe129) MRI is a novel imaging method to provide 3-D mapping of both ventilation and gas exchange in the human lung.

PURPOSE

To evaluate the functional changes in adults with asthma as compared to healthy controls using Xe129 MRI.

METHODS

All subjects (20 controls and 20 asthmatics) underwent lung function measurements and Xe129 MRI on the same day. Outcome measures included the pulmonary ventilation defect and transfer of inspired Xe129 into two soluble compartments: tissue and blood. Ten asthmatics underwent Xe129 MRI before and after bronchodilator to test whether gas transfer measures change with bronchodilator effects.

RESULTS

Initial analysis of the results revealed striking differences in gas transfer measures based on age, hence we compared outcomes in younger (n = 24, ≤ 35 years) versus older (n = 16, > 45 years) asthmatics and controls. The younger asthmatics exhibited significantly lower Xe129 gas uptake by lung tissue (Asthmatic: 0.98% ± 0.24%, Control: 1.17% ± 0.12%, P = 0.035), and higher Xe129 gas transfer from tissue to the blood (Asthmatic: 0.40 ± 0.10, Control: 0.31% ± 0.03%, P = 0.035) than the younger controls. No significant difference in Xe129 gas transfer was observed in the older group between asthmatics and controls (P > 0.05). No significant change in Xe129 transfer was observed before and after bronchodilator treatment.

CONCLUSIONS

By using Xe129 MRI, we discovered heterogeneous alterations of gas transfer that have associations with age. This finding suggests a heretofore unrecognized physiological derangement in the gas/tissue/blood interface in young adults with asthma that deserves further study.

Quantitative CT Scan Imaging of the Airways for Diagnosis and Management of Lung Disease

CT scan imaging provides high-resolution images of the lungs in patients with chronic respiratory diseases. Extensive research over the last several decades has focused on developing novel quantitative CT scan airway measurements that reflect abnormal airway structure. Despite many observational studies demonstrating that associations between CT scan airway measurements and clinically important outcomes such as morbidity, mortality, and lung function decline, few quantitative CT scan measurements are applied in clinical practice. This article provides an overview of the relevant methodologic considerations for implementing quantitative CT scan airway analyses and provides a review of the scientific literature involving quantitative CT scan airway measurements used in clinical or randomized trials and observational studies of humans. We also discuss emerging evidence for the clinical usefulness of quantitative CT scan imaging of the airways and discuss what is required to bridge the gap between research and clinical application. CT scan airway measurements continue to improve our understanding of disease pathophysiologic features, diagnosis, and outcomes. However, a literature review revealed a need for studies evaluating clinical benefit when quantitative CT scan imaging is applied in the clinical setting. Technical standards for quantitative CT scan imaging of the airways and high-quality evidence of clinical benefit from management guided by quantitative CT scan imaging of the airways are required.

Eosinophils and tissue remodeling: Relevance to airway disease

The ability of human tissue to reorganize and restore its existing structure underlies tissue homeostasis in the healthy airways, but in disease can persist without normal resolution, leading to an altered airway structure. Eosinophils play a cardinal role in airway remodeling both in health and disease, driving epithelial homeostasis and extracellular matrix turnover. Physiological consequences associated with eosinophil-driven remodeling include impaired lung function and reduced bronchodilator reversibility in asthma, and obstructed airflow in chronic rhinosinusitis with nasal polyps. Given the contribution of airway remodeling to the development and persistence of symptoms in airways disease, targeting remodeling is an important therapeutic consideration. Indeed, there is early evidence that eosinophil attenuation may reduce remodeling and disease progression in asthma. This review provides an overview of tissue remodeling in both health and airway disease with a particular focus on eosinophilic asthma and chronic rhinosinusitis with nasal polyps, as well as the role of eosinophils in these processes and the implications for therapeutic interventions. Areas for future research are also noted, to help improve our understanding of the homeostatic and pathological roles of eosinophils in tissue remodeling, which should aid the development of targeted and effective treatments for eosinophilic diseases of the airways.

Higher Prevalence and Severity of Eosinophilic Otitis Media in Patients with Asthma-COPD Overlap Compared with Asthma Alone

INTRODUCTION

Eosinophilic otitis media (EOM) is well-known to frequently co-exist with adult-onset asthma. Both diseases are similar type 2 inflammation and are considered to have a "one airway, one disease" relationship. Asthma-chronic obstructive pulmonary disease (COPD) overlap (ACO), characterized by airway obstruction caused by airway wall thickening (AWT), is a severe condition with a higher incidence of mortality compared to asthma alone or COPD alone. Based on the "one airway, one disease" concept, we hypothesized that the inflammatory pathophysiology of EOM differs depending on its comorbidity with ACO or with asthma alone.

METHODS

A total of 77 chronic rhinosinusitis (CRS) patients with asthma were enrolled in this study. The subjects were divided into 2 groups: a group with comorbid asthma alone (asthma group; 46 patients), and a group with comorbid ACO (ACO group; 31 patients). The 2 groups were compared and assessed with regard to various factors, including the patients' clinical characteristics, prevalence rate of EOM, EOM severity, EOMs relationships with smoking and AWT, and the eosinophil and neutrophil cell counts in the middle ear effusion (MEE).

RESULTS

The ACO group included significantly more males (p < 0.05), was significantly older (p < 0.05), and showed significantly lower lung function values (FEV1 [L], FEV1 [%pred]) (p < 0.01) compared with the asthma group. The ACO group also had a significant history of smoking as shown by the Brinkman index (p < 0.01) and greater AWT as assessed by high-resolution computed tomography (p < 0.05). The EOM prevalence rate was significantly higher in the ACO group (p < 0.05), especially with increased ACO severity (p < 0.05). The EOM severity was also significantly higher in the ACO group (p < 0.05) and also correlated with the ACO severity (p < 0.05). The pretreatment ear clinical characteristics score and the average air conduction hearing level were significantly higher in the ACO group (p < 0.05). The eosinophil percentage in the MEE/otorrhea was significantly lower in the ACO group (25.3%) than in the asthma group (54.7%) (p < 0.05). Conversely, the neutrophil percentage was significantly higher in the ACO group (75.7% vs. 41.9%) (p < 0.05).

CONCLUSIONS

Our findings suggest that, in CRS patients with asthma, comorbidity with ACO may be a clinical factor leading to increased EOM prevalence and severity, as well as a higher neutrophil infiltration percentage in the middle ear. Cessation of smoking and early therapeutic intervention for ACO may mitigate progression of bronchial remodeling (i.e., reduce AWT) and help reduce the prevalence and severity of EOM.

Bronchodilator Responsiveness Defined by the 2005 and 2021 ERS/ATS Criteria in Patients with Asthma as Well as Chronic Obstructive Pulmonary Disease

Background

In the 2021 ERS/ATS interpretive strategies for routine lung function tests, a positive bronchodilator response (BDR) was updated as a change of >10% relative to the predicted value in forced expiratory volume in 1 second (FEV₁) or forced vital capacity (FVC). We aimed to explore the differences between the 2005 and 2021 ERS/ATS criteria applied to patients with asthma as well as chronic obstructive pulmonary disease (COPD).

Methods

BDR test data about asthma patients aged 6–80 years and COPD patients aged 18–80 years were derived from the National Respiratory Medicine Center, First Affiliated Hospital of Guangzhou Medical University, from January 2017 to March 2022. BDR results defined by the 2005 and 2021 ERS/ATS criteria were named 2005-BDR and 2021-BDR, respectively. We compared differences between 2005-BDR and 2021-BDR and analyzed the trend in the proportion of positive BDR (BDR+) with the level of airflow obstruction.

Results

A total of 4457 patients with asthma and 7764 patients with COPD were included in the analysis. The percentages of 2005-BDR+ and 2021-BDR+ were 63.32% and 52.84% for asthma, 30.92% and 22.94% for COPD, respectively. Of patients with 2005-BDR+, 81.86% for asthma and 70.18% for COPD showed 2021-BDR+ results, and these patients had higher FEV₁%pred, FVC%pred (all P<0.05). Whichever BDR criterion was adopted, the proportion of BDR+ had an upward linear trend with the increased degree of airflow obstruction in COPD, but exhibited an approximate inverted U-shaped curve in asthma. In COPD, the proportion of BDR_FEV1 was negatively associated with the degree of airflow obstruction, while BDR_FVC was positively associated (all P<0.05).

Conclusion

Compared with 2005-BDR+, the proportion of 2021-BDR+ reduced markedly in patients with asthma and COPD, but their trends with the degree of airflow obstruction did not change. Patients with consistent BDR+ had higher initial FEV₁%pred and FVC%pred.

Morphological features of bronchiectasis in patients with non-tuberculous mycobacteriosis and interstitial pneumonia

Objective

To compare the morphological features of bronchiectasis between patients with different underlying diseases, we performed quantitative analysis of high-resolution computed tomography (HRCT) images of 14 patients with non-tuberculous mycobacteriosis (NTM) and 13 with idiopathic pulmonary fibrosis (IPF). A 3D image of the bronchial structure was made from HRCT data. Bronchiectasis was defined as abnormal dilatation of the bronchi with the diameter greater than that of the accompanying pulmonary artery. We measured the inner and outer diameters, wall area as %total airway cross sectional area (WA%), and wall thickness to airway diameter ratio (T/D) of the 4-8th generations of bronchi.

Results

In patients with IPF, the inner and outer diameters linearly decreased toward the distal bronchi. In contrast, the inner and outer diameters of NTM fluctuated. The coefficient of variation of the outer diameters of the 6-7th generations of bronchi was larger in the NTM patients than in those with IPF, whereas no significant difference was observed in the coefficient of variation of the inner diameters between the groups. In IPF patients, WA% and T/D varied between the generation of bronchi, but the coefficient of variation of WA% and T/D was relatively small in those with NTM.

Imaging in Asthma Management

Asthma is a heterogeneous disease characterized by chronic airway inflammation that affects more than 300 million people worldwide. Clinically, asthma has a widely variable presentation and is defined based on a history of respiratory symptoms alongside airflow limitation. Imaging is not needed to confirm a diagnosis of asthma, and thus the use of imaging in asthma has historically been limited to excluding alternative diagnoses. However, significant advances continue to be made in novel imaging methodologies, which have been increasingly used to better understand respiratory impairment in asthma. As a disease primarily impacting the airways, asthma is best understood by imaging methods with the ability to elucidate airway impairment. Techniques such as computed tomography, magnetic resonance imaging with gaseous contrast agents, and positron emission tomography enable assessment of the small airways. Others, such as optical coherence tomography and endobronchial ultrasound enable high-resolution imaging of the large airways accessible to bronchoscopy. These imaging techniques are providing new insights in the pathophysiology and treatments of asthma and are poised to impact the clinical management of asthma.

Role of Th17 Cytokines in Airway Remodeling in Asthma and Therapy Perspectives

Airway remodeling is a frequent pathological feature of severe asthma leading to permanent airway obstruction in up to 50% of cases and to respiratory disability. Although structural changes related to airway remodeling are well-characterized, immunological processes triggering and maintaining this phenomenon are still poorly understood. As a consequence, no biotherapy targeting cytokines are currently efficient to treat airway remodeling and only bronchial thermoplasty may have an effect on bronchial nerves and smooth muscles with uncertain clinical relevance. Th17 cytokines, including interleukin (IL)-17 and IL-22, play a role in neutrophilic inflammation in severe asthma and may be involved in airway remodeling. Indeed, IL-17 is increased in sputum from severe asthmatic patients, induces the expression of "profibrotic" cytokines by epithelial, endothelial cells and fibroblasts, and provokes human airway smooth muscle cell migration in in vitro studies. IL-22 is also increased in asthmatic samples, promotes myofibroblast differentiation, epithelial-mesenchymal transition and proliferation and migration of smooth muscle cells in vitro. Accordingly, we also found high levels of IL-17 and IL-22 in a mouse model of dog-allergen induced asthma characterized by a strong airway remodeling. Clinical trials found no effect of therapy targeting IL-17 in an unselected population of asthmatic patients but showed a potential benefit in a sub-population of patients exhibiting a high level of airway reversibility, suggesting a potential role on airway remodeling. Anti-IL-22 therapies have not been evaluated in asthma yet but were demonstrated efficient in severe atopic dermatitis including an effect on skin remodeling. In this review, we will address the role of Th17 cytokines in airway remodeling through data from in vitro, in vivo and translational studies, and examine the potential place of Th17-targeting therapies in the treatment of asthma with airway remodeling.

Therapeutic effect of statins on airway remodeling during asthma

INTRODUCTION

Asthma is a chronic inflammatory disease of the airways, which is usually characterized by remodeling, hyperresponsiveness and episodic obstruction of the airways. The underlying chronic airway inflammation leads to pathological restructuring of both the large and small airways. Since the effects of current asthma medications on airway remodeling have been met with contradictions, many therapeutic agents have been redirected from their primary use for the treatment of asthma. Such treatments, which could target several signaling molecules implicated in the inflammatory and airway remodeling processes of asthma, would be an ideal choice.

AREAS COVERED

Statins are effective serum cholesterol-lowering agents that were found to have potential anti-inflammatory and anti-remodeling properties. Literature search was done for the past 10 years to include research and review articles in the field of statins and asthma complications. In this review, we discuss the role of statins in airway tissue remodeling and their potential therapeutic modalities in asthma.

EXPERT OPINION

With improved understanding of the role of statins in airway remodeling and inflammation, statins represent a potential therapeutic option for various asthma phenotypes. Further research is warranted to optimize statins for asthma therapy through inhalation as a possible route of administration.

Quantification of Airway Dimensions using a High-Resolution CT Scanner: A Phantom Study

PURPOSE

Small airways with inner diameters less than 2 mm are sites of major airflow limitations in patients with chronic obstructive pulmonary disease (COPD) and asthma. The purpose of this study is to investigate the limitations for accurate assessment of small airway dimensions using both high-resolution CT (HRCT) and conventional normal-resolution CT at low dose levels.

METHODS

To model the normal human airways from the 3^rd to 20^th generations, a cylindrical polyurethane phantom with 14 airway tubes of inner diameters (ID) ranging from 0.3 to 3.4 mm and wall thicknesses (WT) ranging from 0.15 to 1.6 mm was placed within an Anthropomorphic QRM-Thorax phantom. The Aquilion Precision (Canon Medical Systems Corporation) HRCT scanner was used to acquire images at 80, 100 and 120 kV using high resolution mode (HR, 0.25 mm x 160 detector configuration) and normal resolution mode (NR, 0.5 mm x 80 detector configuration). The HR data were reconstructed using 1024 x 1024 matrix (0.22 x 0.22 x 0.25 mm voxel size) and the NR data were reconstructed using a 512 x 512 matrix (0.43 x 0.43 x 0.50 mm). Two reconstruction algorithms (filtered back projection; FBP and an adaptive iterative dose reduction 3D algorithm; AIDR 3D) and three reconstruction kernels (FC30, FC52 and FC56) were investigated. The CTDI_vol dose values ranged from 0.2 to 6.2 mGy. A refined automated full-width half-maximum (FWHM) method was used for the measurement of airway dimensions, where the density profiles were computed by radial oversampling using a polar coordinate system. Both ID and WT were compared to the known dimensions using a regression model, and the root-mean-squared-error (RMSE) and average error were computed across all 14 airway tubes.

RESULTS

The results indicate that the ID can be measured within a 15% error down to approximately 0.8 mm and 2.0 mm using the HR and NR modes, respectively. The overall RMSE (and average error) of ID measurements for HR and NR were 0.10 mm (-0.70%) and 0.31 mm (-2.63%), respectively. The RMSE (and average error) of WT measurements using HR and NR were 0.10 mm (23.27%) and 0.27 mm (53.56%), respectively. The WT measurement using HR yielded a factor of two improvement in accuracy as compared to NR.

CONCLUSIONS

High-resolution CT can provide more accurate measurements of airway dimensions as compared with normal resolution CT, potentially improving quantitative assessment of pathologies such as COPD and asthma. The high resolution mode acquired and reconstructed with AIDR3D and the FC52 kernel provides most accurate measurement of airway dimensions. Low-dose high resolution measurements at dose level above 0.9 mGy can provide improved accuracy on both inner diameters and wall thicknesses compared to full dose normal resolution airway phantom measurements.

Hypoxia-induced preadipocyte factor 1 expression in human lung fibroblasts through ERK/PEA3/c-Jun pathway

Background

Several studies have reported that hypoxia plays a pathological role in severe asthma and tissue fibrosis. Our previous study showed that hypoxia induces A disintegrin and metalloproteinase 17 (ADAM17) expression in human lung fibroblasts. Moreover, preadipocyte factor 1 (Pref-1) is cleaved by ADAM17, which participates in adipocyte differentiation. Furthermore, Pref­1 overexpression is involved in tissue fibrosis including liver and heart. Extracellular signal-regulated kinase (ERK) could active downstram gene expression through polyoma enhancer activator 3 (PEA3) phosphorylation. Studies have demonstrated that PEA3 and activator protein 1 (AP-1) play crucial roles in lung fibrosis, and the Pref-1 promoter region contains PEA3 and AP-1 binding sites as predicted. However, the roles of ERK, PEA3, and AP-1 in hypoxia-stimulated Pref-1 expression in human lung fibroblasts remain unknown.

Methods

The protein expression in ovalbumin (OVA)-induced asthmatic mice was performed by immunohistochemistry and immunofluorescence. The protein expression or the mRNA level in human lung fibroblasts (WI-38) was detected by western blot or quantitative PCR. Small interfering (si) RNA was used to knockdown gene expression. The collaboration with PEA3 and c-Jun were determined by coimmunoprecipitation. Translocation of PEA3 from the cytosol to the nucleus was observed by immunocytochemistry. The binding ability of PEA3 and AP-1 to Pref-1 promoter was assessed by chromatin immunoprecipitation.

Results

Pref-1 and hypoxia-inducible factor 1α (HIF-1α) were expressed in the lung sections of OVA-treated mice. Colocalization of PEA3 and Fibronectin was detected in lung sections from OVA-treated mice. Futhermore, Hypoxia induced Pref­1 protein upregulation and mRNA expression in human lung fibroblasts (WI­38 cells). In 60 confluent WI-38 cells, hypoxia up-regulated HIF-1α and Pref-1 protein expression. Moreover, PEA3 small interfering (si) RNA decreased the expression of hypoxia-induced Pref­1 in WI­38 cells. Hypoxia induced PEA3 phosphorylation, translocation of PEA3 from the cytosol to the nucleus, PEA3 recruitment and AP-1 binding to the Pref­1 promoter region, and PEA3-luciferase activity. Additionally, hypoxia induced c-Jun-PEA3 complex formation. U0126 (an ERK inhibitor), curcumin (an AP­1 inhibitor) or c-Jun siRNA downregulated hypoxia-induced Pref-1 expression.

Conclusions

These results implied that ERK, PEA3, and AP­1 participate in hypoxia­induced Pref­1 expression in human lung fibroblasts.

The lower respiratory airway wall in children in health and disease

Alone or in association with other lung or thorax component disorders, the airway wall (AWW) remains one of the most frequently involved elements in paediatric lung diseases. A myriad of AWW disorders will present with similar symptomatology. It is thus important for the clinician to reappraise the normal development and structure of the AWW to better understand the underlying disease patterns. We herein provide an overview of the structure of the AWW and a description of its development from the fetal period to adulthood. We also detail the most common AWW changes observed in several acute and chronic respiratory disorders as well as after cigarette smoke or chronic pollution exposure. We then describe the relationship between the AWW structure and lung function. In addition, we present the different ways of investigating the AWW structure, from biopsies and histological analyses to the most recent noninvasive airway (AW) imaging techniques. Understanding the pathophysiological processes involved in an individual patient will lead to the judicious choice of nonspecific or specific personalised treatments, in order to prevent irreversible AW damage.

Assessment of Airway Remodeling Using Endobronchial Ultrasound in Asthma-COPD Overlap

PURPOSE

The aim of this study was to evaluate the structural changes of the airways using the endobronchial ultrasound (EBUS) in ACO patients compared to severe asthma and COPD patients.

PATIENTS AND METHODS

The study included 17 patients with ACO, 17 patients with COPD and 33 patients with severe asthma. Detailed clinical data were obtained from all participants. Basic laboratory tests were performed, including measurement of eosinophil counts in blood and serum immunoglobulin E (IgE) concentrations. All patients underwent spirometry and bronchoscopy with EBUS (a 20‑MHz ultrasound probe) to measure the total thicknesses of the bronchial walls and their particular layers in segmental bronchi of the right lower lobe. EBUS allows to distinguish five layers of the bronchial wall. Layer 1 (L1) and layer 2 (L2) were analyzed separately, while the outer layers (layers 3-5 [L3-5]) that correspond to cartilage were assessed together.

RESULTS

In patients with ACO the thicknesses of the L1 and L2 layers, which are mainly responsible for remodeling, were significantly greater than in patients with COPD and significantly smaller than in patients with severe asthma (median L1= 0.17 mm vs 0.16 mm vs 0.18 mm, p<0.001; median L2= 0.18 mm vs 0.17 mm vs 0.20 mm, p<0.001, respectively). The thicknesses of the total bronchial walls (L1+L2+L3-5) and L3-5 were significantly smaller in ACO and COPD patients compared to asthma patients (median L1+L2+L3-5= 1.2 mm vs 1.14 mm vs 1.31 mm, p<0.001; median L3-5= 0.85 mm vs, 0.81 mm vs 0.92 mm, p=0.001, respectively).

CONCLUSION

The process of structural changes in the airways assessed by EBUS is more advanced in individuals with ACO compared to patients with COPD, and less pronounced compared to patients with severe asthma. It seems that EBUS may provide useful information about differences in airway remodeling between ACO, COPD and severe asthma.

Interactions via α2β1 Cell Integrin May Protect against the Progression of Airway Structural Changes in Asthma

Increased airway wall thickness and remodeling of bronchial mucosa are characteristic of asthma and may arise from altered integrin signaling on airway cells. Here, we analyzed the expression of β₁-subfamily integrins on blood and airway cells (flow cytometry), inflammatory biomarkers in serum and bronchoalveolar lavage, reticular basement membrane (RBM) thickness and collagen deposits in the mucosa (histology), and airway geometry (CT-imaging) in 92 asthma patients (persistent airflow limitation subtype: n = 47) and 36 controls. Persistent airflow limitation was associated with type-2 inflammation, elevated soluble α₂ integrin chain, and changes in the bronchial wall geometry. Both subtypes of asthma showed thicker RBM than control, but collagen deposition and epithelial α₁ and α₂ integrins staining were similar. Type-I collagen accumulation and RBM thickness were inversely related to the epithelial expression of the α₂ integrin chain. Expression of α₂β₁ integrin on T-cells and eosinophils was not altered in asthma. Collagen I deposits were, however, more abundant in patients with lower α₂β₁ integrin on blood and airway CD8⁺ T-cells. Thicker airway walls in CT were associated with lower α₂ integrin chain on blood CD4⁺ T-cells and airway eosinophils. Our data suggest that α₂β₁ integrin on inflammatory and epithelial cells may protect against airway remodeling advancement in asthma.

Evaluation of bronchial wall thickness in asthma using magnetic resonance imaging

BACKGROUND

Bronchial thickening is a pathological feature of asthma that has been evaluated using computed tomography (CT), an ionised radiation technique. Magnetic Resonance Imaging (MRI) with Ultrashort Echo Time (UTE) pulse sequences could be an alternative to CT.

OBJECTIVES

To measure bronchial dimensions using MRI-UTE in asthmatic patients, by evaluating the accuracy and agreement with CT, by comparing severe and non-severe asthma and by correlating with pulmonary function tests.

METHODS

We assessed bronchial dimensions (wall area (WA), lumen area (LA), normalised wall area (WA%), and wall thickness (WT)) by MRI-UTE and CT in 15 non-severe and 15 age- and sex-matched severe asthmatic patients (NCT03089346). Accuracy and agreement between MRI and CT was evaluated by paired t-tests and Bland-Altman analysis. Reproducibility was assessed by intra-class correlation coefficient and Bland-Altman analysis. Comparison between non-severe and severe asthmatic parameters was performed by Student-t, Mann-Whitney or Fisher's Exact tests. Correlations were assessed by Pearson or Spearman coefficients.

RESULTS

LA, WA%, and WT were not significantly different between MRI-UTE and CT, with good correlations and concordance. Inter- and intra-observer reproducibility was moderate to good. WA% and WT were both higher in severe than in non-severe asthmatic patients. WA, WA% and WT were all negatively correlated with FEV1.

CONCLUSION

We demonstrated that MRI-UTE is an accurate and reliable radiation-free method to assess bronchial wall dimensions in asthma, with enough spatial resolution to differentiate severe from non-severe asthma.

Quantitative evaluation of computed tomography findings in patients with bronchial asthma: prediction of therapeutic response

INTRODUCTION

To compare pretreatment quantitative CT parameters between patients with well-controlled and those with poorly controlled bronchial asthma after treatment.

METHODS

We retrospectively reviewed 785 patients with clinical diagnosis of bronchial asthma from January 2009 to April 2015. Of these, 43 patients underwent high-resolution CT and pulmonary function tests at initial diagnosis. According to the Global Initiative for Asthma (GINA) 2015 guidelines, the patients were classified into two groups (well-controlled (GINA1), n = 18; poorly controlled (GINA2 and GINA3), n = 25). Quantitative measurements for airways (total cross-sectional area (TA), lumen area (LA), wall area (WA) and wall area percentage (WA%)), air trapping and emphysema were performed on initial pretreatment CT scans. We compared CT measurements for airways between well-controlled and poorly controlled groups and also compared those between ever-smokers and never-smokers. The significant quantitative CT parameters were evaluated with multiple regression analysis.

RESULTS

The TA and the WA demonstrated significantly higher values in the poorly controlled than in the well-controlled patient group (TA in RB1 and LB1, each P < 0.05; WA in RB1 and RB8, each P < 0.05). Quantitative parameters for air trapping and emphysema did not show significant differences between the two patient groups. On multiple regression analysis, the TA and the WA were statistically significant in comparison of two patient groups with an adjustment for age, sex, body mass index and smoking history (each P < 0.05). Significantly higher values of the WA and the WA% were revealed in the asthmatics with smoking history comparing to non-smokers (P < 0.05).

CONCLUSION

Most of the quantitative CT measurements did not correlate significantly with clinical outcomes in patients with bronchial asthma. And, further research that supplements the limitations of this study is needed to support and validate the association between CT parameters and therapeutic response. This can be justified by the fact that a trend of higher values in airway measurements on initial pretreatment HRCT scan in the poorly controlled than in the well-controlled patient group.

Role of Collagen in Airway Mechanics

Collagen is the most abundant airway extracellular matrix component and is the primary determinant of mechanical airway properties. Abnormal airway collagen deposition is associated with the pathogenesis and progression of airway disease. Thus, understanding how collagen affects healthy airway tissue mechanics is essential. The impact of abnormal collagen deposition and tissue stiffness has been an area of interest in pulmonary diseases such as cystic fibrosis, asthma, and chronic obstructive pulmonary disease. In this review, we discuss (1) the role of collagen in airway mechanics, (2) macro- and micro-scale approaches to quantify airway mechanics, and (3) pathologic changes associated with collagen deposition in airway diseases. These studies provide important insights into the role of collagen in airway mechanics. We summarize their achievements and seek to provide biomechanical clues for targeted therapies and regenerative medicine to treat airway pathology and address airway defects.

High-resolution CT pulmonary findings in children with severe asthma

OBJECTIVE

To compare quantitative CT parameters between children with severe asthma and healthy subjects, correlating to their clinical features.

METHODS

We retrospectively analyzed CT data from 19 school-aged children (5-17 years) with severe asthma and 19 control school-aged children with pectus excavatum. The following CT parameters were evaluated: total lung volume (TLV), mean lung density (MLD), CT air trapping index (AT%) (attenuation ≤856 HU), airway wall thickness (AWT), and percentage of airway wall thickness (AWT%). Multi-detector computed tomography (MDCT) data were correlated to the following clinical parameters: forced expiratory volume in 1 s (FEV1), forced vital capacity (FVC), forced expiratory flow at 25-75% (FEF 25-75%), FEV1/FVC ratio, sputum and bronchoalveolar lavage analysis, serum IgE levels, and previous hospitalizations due to asthma.

RESULTS

Asthma patients presented higher mean values of AT% (23.8 ± 6.7% vs. controls, 9.7 ± 3.2%), AWT (1.46 ± 0.22 mm vs. controls, 0.47 ± -735 ± 28 HU vs. controls, -666 ± 19 HU). Mean AT% was 29.0 ± 4.7% in subjects with previous hospitalization against 19.2 ± 5.0% in those with no prior hospitalization (p < 0.001). AT% presented very strong negative correlations with FVC (r = -0.933, p < 0.001) and FEV1 (r = -0.841, p < 0.001) and a moderate correlation with FEF 25-75% (r = -0.608, p = 0.007). AT% correlation with FEV1/FVC ratio and serum IgE was weak (r = -0.184, p = 0.452, and r = -0.363, p = 0.202) CONCLUSION: Children with severe asthma present differences in quantitative chest CT scans compared to healthy controls with strong correlations with pulmonary function tests and previous hospitalizations due to asthma.

Quantitative assessment of airway remodelling and response to allergen in asthma

BACKGROUND AND OBJECTIVE

In vivo evaluation of the microstructural differences between asthmatic and non-asthmatic airways and their functional consequences is relevant to understanding and, potentially, treating asthma. In this study, we use endobronchial optical coherence tomography to investigate how allergic airways with asthma differ from allergic non-asthmatic airways in baseline microstructure and in response to allergen challenge.

METHODS

A total of 45 subjects completed the study, including 20 allergic, mildly asthmatic individuals, 22 non-asthmatic allergic controls and 3 healthy controls. A 3-cm airway segment in the right middle and right upper lobe were imaged in each subject immediately before and 24 h following segmental allergen challenge to the right middle lobe. Relationships between optical airway measurements (epithelial and mucosal thicknesses, mucosal buckling and mucus) and airway obstruction (FEV1 /FVC (forced expiratory volume in 1 s/forced vital capacity) and FEV1 % (FEV1 as a percentage of predictive value)) were investigated.

RESULTS

Significant increases at baseline and in response to allergen were observed for all four of our imaging metrics in the asthmatic airways compared to the non-asthmatic airways. Epithelial thickness and mucosal buckling exhibited a significant relationship to FEV1 /FVC in the asthmatic group.

CONCLUSION

Simultaneous assessments of airway microstructure, buckling and mucus revealed both structural and functional differences between the mildly asthmatic and control groups, with airway buckling seeming to be the most relevant factor. The results of this study demonstrate that a comprehensive, microstructural approach to assessing the airways may be important in future asthma studies as well as in the monitoring and treatment of asthma.

Structural lung abnormalities on computed tomography correlate with asthma inflammation in bronchoscopic alveolar lavage fluid

Objective: Image scoring systems have been developed to assess the severity of specific lung abnormalities in patients diagnosed with various pulmonary diseases except for asthma. A comprehensive asthma imaging scoring system may identify specific abnormalities potentially linking these to inflammatory phenotypes.Methods: Computed tomography (CT) images of 88 children with asthma (50 M/38 F, mean age 7.8 ± 5.4 years) acquired within 12 months of bronchoscopic alveolar lavage fluid (BALF) sampling that assessed airway inflammation cell types were reviewed along with CT images of 49 controls (27 M/22 F, mean age 3.4 ± 2.2 years). Images were scored using a comprehensive scoring system to quantify bronchiectasis (BR), bronchial wall thickening (BWT), ground glass opacity, mucus plugging (MP), consolidations, linear densities (LD), and air trapping (AT). Each category was scored 0-2 in each of six lobar regions (with lingula separated from left upper lobe).Results: Absolute average overall scores of the controls and children with asthma were 0.72 ± 1.59 and 5.39 ± 5.83, respectively (P < 0.0001). Children with asthma scored significantly higher for BR (N = 20, 0.33 ± 0.80, P = 0.0002), BWT (N = 28, 0.72 ± 1.40, P < 0.0001), MP (N = 28, 0.37 ± 1.12, P = 0.0052), consolidation (N = 31, 0.67 ± 1.22, P < 0.0001), LD (N = 58, 1.12 ± 1.44, P < 0.0001), and AT (N = 52, 1.78 ± 2.31, P < 0.0001). There was a significant difference between the BR score of children with positive inflammatory response in BALF (N = 53) and those who were negative for airway inflammation cells (0.14 ± 0.36, P = 0.040).Conclusions: Significant lung structural abnormalities were readily identified on CT of children with asthma, with image differentiation of those with an inflammatory response on BALF. Chest imaging demonstrates potential as a noninvasive clinical tool for additional characterization of asthma phenotypes.

Small airway dysfunction may be an indicator of early asthma: findings from high-resolution CT

BACKGROUND

Increasing attention is now focused on the role of the small airways in asthma. Patients with small airway asthma typically have a preserved forced expiratory volume in 1 second, with disproportionate small airway dysfunction.

OBJECTIVE

The aim of this study was to determine whether there are structural changes in the large airways in patients with small airway asthma.

METHODS

Nine patients with small airway asthma and 20 healthy controls underwent high-resolution computed tomography (HRCT) scan. The apicoposterior segmental bronchus in the left upper lobe (LB1+2) and the posterior basal segmental bronchus in the left lower lobe (LB10) were identified on HRCT images. The luminal area (LA), wall area (WA), and wall area percentage (WA%) of each bronchus were measured from the 2nd (lobar) to the 6th generation and compared between the patients with small airway asthma and the healthy controls.

RESULTS

The WA% of the 6th generation in the patients with small airway asthma was higher than that in the healthy controls; the difference was statistically significant (LB1 + 2, P = .040; LB10, P = .033).

CONCLUSION

Structural changes in the large airways of patients with small airway asthma may represent an early stage of asthma.

Fibroblast-to-myofibroblast transition in bronchial asthma

Bronchial asthma is a chronic inflammatory disease in which bronchial wall remodelling plays a significant role. This phenomenon is related to enhanced proliferation of airway smooth muscle cells, elevated extracellular matrix protein secretion and an increased number of myofibroblasts. Phenotypic fibroblast-to-myofibroblast transition represents one of the primary mechanisms by which myofibroblasts arise in fibrotic lung tissue. Fibroblast-to-myofibroblast transition requires a combination of several types of factors, the most important of which are divided into humoural and mechanical factors, as well as certain extracellular matrix proteins. Despite intensive research on the nature of this process, its underlying mechanisms during bronchial airway wall remodelling in asthma are not yet fully clarified. This review focuses on what is known about the nature of fibroblast-to-myofibroblast transition in asthma. We aim to consider possible mechanisms and conditions that may play an important role in fibroblast-to-myofibroblast transition but have not yet been discussed in this context. Recent studies have shown that some inherent and previously undescribed features of fibroblasts can also play a significant role in fibroblast-to-myofibroblast transition. Differences observed between asthmatic and non-asthmatic bronchial fibroblasts (e.g., response to transforming growth factor β, cell shape, elasticity, and protein expression profile) may have a crucial influence on this phenomenon. An accurate understanding and recognition of all factors affecting fibroblast-to-myofibroblast transition might provide an opportunity to discover efficient methods of counteracting this phenomenon.

Quantitative CT detects changes in airway dimensions and air-trapping after bronchial thermoplasty for severe asthma

OBJECTIVES

Bronchial thermoplasty (BT) can be considered in the treatment of severe asthma to reduce airway smooth muscle mass and bronchoconstriction. We hypothesized that BT may thus have long-term effects on airway dimensions and air-trapping detectable by quantitative computed tomography (QCT).

METHODS

Paired in- and expiratory CT and inspiratory CT were acquired in 17 patients with severe asthma before and up to two years after bronchial thermoplasty and in 11 additional conservatively treated patients with serve asthma, respectively. A fully automatic software calculated the airways metrics for wall thickness (WT), wall percentage (WP), lumen area (LA) and total diameter (TD). Furthermore, lung air-trapping was quantified by determining the quotient of mean lung attenuation in expiration vs. inspiration (E/I MLA) and relative volume change in the Hounsfield interval -950 to -856 in expiration to inspiration (RVC_856-950) in a generation- and lobe-based approach, respectively.

RESULTS

BT reduced WT for the combined analysis of the 2nd-7th airway generation significantly by 0.06 mm (p = 0.026) and WP by 2.05% (p < 0.001), whereas LA and TD did not change significantly (p = 0.147, p = 0.706). No significant changes were found in the control group. Furthermore, E/I MLA and RVC_856-950 decreased significantly after BT by 12.65% and 1.77% (p < 0.001), respectively.

CONCLUSION

BT significantly reduced airway narrowing and air-trapping in patients with severe asthma. This can be interpreted as direct therapeutic effects caused by a reduction in airway-smooth muscle mass and changes in innervation. A reduction in air-trapping indicates an influence on more peripheral airways not directly treated by the BT procedure.

Attenuation profile matching: An accurate and scan parameter-robust measurement method for small airway dimensions in low-dose CT scans

PURPOSE

The dimensions of small airways with an internal diameter of less than 2-3 mm are important biomarkers for the evaluation of pulmonary diseases, such as asthma and chronic obstructive pulmonary disease (COPD). The resolution limitations of CT systems, however, have remained a barrier to be of use for determining the small airway dimensions. We present a novel approach, called the attenuation profile matching (APM) method, which allows for the accurate determination of the small airway dimension while being robust to varying CT scan parameters.

METHOD

For generating the synthetic attenuation profiles of an airway, we acquired and employed the point spread functions of a CT system by calculating its convolution with numerical airway models with varying wall thicknesses. The dimensions of a given airway were determined as per the numerical model yielding minimum error between the measured and the synthetic attenuation profiles across the airway.

RESULTS

In a phantom study with airway tubes, the APM method proved to be highly accurate in determining airway wall dimensions. The measurement error for the smallest tube (0.6 mm thickness, 3 mm diameter) was merely 0.02 mm (3.3%) in wall thickness and 0.17 mm (5.6%) in lumen diameter. In a pilot clinical test, the APM method was able to distinguish the airway wall thicknesses of COPD cases (1.16 ± 0.23 mm) from those of normal subjects (0.6 ± 0.18 mm), while the measurements using the full width at half maximum method substantially overlapped (1.45 ± 0.32 mm vs. 1.28 ± 0.30 mm, respectively) and were barely distinguishable from each other.

CONCLUSION

Our proposed APM method has the potential to overcome the resolution limitations of current CT systems and accurately determine the small airway dimensions in COPD patients.

Asthma Phenotypes and Endotypes: Implications for Personalised Therapy

Asthma is increasingly recognised as a heterogeneous group of diseases with similar clinical presentations rather than a singular disease entity. Asthma was historically categorised by clinical symptoms; however, newer methods of subgrouping, describing and categorising the disease have sub-defined asthma. These sub-definitions are intermittently called phenotypes or endotypes, but the real meanings of these words are poorly understood. Novel treatments are currently and increasingly available, partly in the monoclonal antibody environment, and also some physical therapies (bronchial thermoplasty), but additionally small molecules are not far away from clinical practice. Understanding the disease pathogenesis and the mechanism of action more completely may enable identification of treatable traits, biomarkers, mediators and modifiable therapeutic targets. However, there remains a danger that clinicians become preoccupied with the concept of endotypes and biomarkers, ignoring therapies that are hugely effective but have no companion biomarker. This review discusses our understanding of the concept of phenotypes and endotypes in appreciating and managing the heterogeneous condition that is asthma. We consider the role of functional imaging, physiology, blood-, sputum- and breath-based biomarkers and clinical manifestations that could be used to produce a personalised asthma profile, with implications on prognosis, pathophysiology and most importantly specific therapeutic responses. With the advent of increasing numbers of biological therapies and other interventional options such as bronchial thermoplasty, the importance of targeting expensive therapies to patients with the best chance of clinical response has huge health economic importance.

Lumen area change (Delta Lumen) between inspiratory and expiratory multidetector computed tomography as a measure of severe outcomes in asthmatic patients

BACKGROUND

Quantitative computed tomographic (QCT) biomarkers of airway morphology hold potential for understanding and monitoring regional airway remodeling in asthmatic patients.

OBJECTIVE

We sought to determine whether the change in airway lumen area between total lung capacity (TLC) and functional residual capacity (FRC) lung volumes measured from CT imaging data was correlated with severe outcomes in asthmatic patients.

METHODS

We studied 152 asthmatic patients (90 female and 62 male patients) and 33 healthy subjects (12 female and 21 male subjects) using QCT. Postprocessing of airways at generations 1 to 5 (1 = trachea) was performed for wall area percentage, wall thickness percentage (WT%), lumen area at baseline total lung capacity (LA_TLC), lumen area at baseline functional residual capacity (LA_FRC), and low attenuation area at FRC. A new metric (reflecting remodeling, distal air trapping, or both), Delta Lumen, was determined as follows: Percentage difference in lumen area (LA_TLC - LA_FRC)/LA_TLC × 100.

RESULTS

Postprocessing of 4501 airway segments was performed (3681 segments in the 152 patients with asthma and 820 segments in the 33 healthy subjects; range, 17-28 segments per subject). Delta Lumen values were negatively correlated with WT% and low attenuation area (P < .01) in asthmatic patients. Delta Lumen values were significantly lower for airway generations 3 to 5 (segmental airways) in subjects undergoing hospitalization because of exacerbation and in patients with refractory asthma requiring treatment with systemic corticosteroids. WT% and low attenuation area were positively and Delta Lumen values were negatively associated with systemic corticosteroid treatment (P < .05), suggesting that a reduced Delta Lumen value is a potential outcome biomarker in patients with severe asthma.

CONCLUSION

Reduced Delta Lumen value in the central airways measured by using QCT is a promising exploratory biomarker of unstable refractory asthma that warrants further study.

Assessment of proximal and peripheral airway dysfunction by computed tomography and respiratory impedance in asthma and COPD patients with fixed airflow obstruction

OBJECTIVE:

To ascertain: (i) if elderly patients with fixed airflow obstruction (FAO) due to asthma and chronic obstructive pulmonary disease (COPD) have distinct airway morphologic and physiologic changes; (ii) the correlation between the morphology of proximal/peripheral airways and respiratory impedance.

METHODS:

Twenty-five asthma cases with FAO and 22 COPD patients were enrolled. High-resolution computed tomography was used to measure the wall area (WA) and lumen area (LA) of the proximal airway at the apical segmental bronchus of the right upper lobe (RB1) adjusted by body surface area (BSA) and bronchial wall thickening (BWT_r) of the peripheral airways and extent of expiratory air trapping (AT_exp). Respiratory impedance included resistance at 5 Hz (R₅) and 20 Hz (R₂₀) and resonant frequency (Fres). Total lung capacity (TLC) and residual volume (RV) were measured.

RESULTS:

Asthma patients had smaller RB1-LA/BSA than COPD patients (10.5 ± 3.4 vs. 13.3 ± 5.0 mm²/m², P = 0.037). R₅(5.5 ± 2.0 vs. 3.4 ± 1.0 cmH₂O/L/s, P = 0.02) and R₂₀(4.2 ± 1.7 vs. 2.6 ± 0.7 cmH₂O/L/s, P = 0.001) were higher in asthma cases. AT_exp and BWT_r were similar in both groups. Regression analysis in asthma showed that forced expiratory volume in one second (FEV₁) and Fres were associated with RB1-WA/BSA (R²= 0.34, P = 0.005) and BWT_r (0.5, 0.012), whereas RV/TLC was associated with AT_exp (0.38, 0.001).

CONCLUSIONS:

Asthma patients with FAO had a smaller LA and higher resistance of the proximal airways than COPD patients. FEV₁ and respiratory impedance correlated with airway morphology.

Free-breathing Functional Pulmonary MRI: Response to Bronchodilator and Bronchoprovocation in Severe Asthma

RATIONALE AND OBJECTIVES

Ventilation heterogeneity is a hallmark feature of asthma. Our objective was to evaluate ventilation heterogeneity in patients with severe asthma, both pre- and post-salbutamol, as well as post-methacholine (MCh) challenge using the lung clearance index, free-breathing pulmonary ¹H magnetic resonance imaging (FDMRI), and inhaled-gas MRI ventilation defect percent (VDP).

MATERIALS AND METHODS

Sixteen severe asthmatics (49 ± 10 years) provided written informed consent to an ethics board-approved protocol. Spirometry, plethysmography, and multiple breath nitrogen washout to measure the lung clearance index were performed during a single visit within 15 minutes of MRI. Inhaled-gas MRI and FDMRI were performed pre- and post-bronchodilator to generate VDP. For asthmatics with forced expiratory volume in 1 second (FEV₁) >70%_predicted, MRI was also performed before and after MCh challenge. Wilcoxon signed-rank tests, Spearman correlations, and a repeated-measures analysis of variance were performed.

RESULTS

Hyperpolarized ³He (P = .02) and FDMRI (P = .02) VDP significantly improved post-salbutamol and for four asthmatics who could perform MCh (n = 4). ³He and FDMRI VDP significantly increased at the provocative concentration of MCh, resulting in a 20% decrease in FEV₁ (PC₂₀) and decreased post-bronchodilator (P = .02), with a significant difference between methods (P = .01). FDMRI VDP was moderately correlated with ³He VDP (ρ = .61, P = .01), but underestimated VDP relative to ³He VDP (-6 ± 9%). Whereas ³He MRI VDP was significantly correlated with the lung clearance index, FDMRI was not (ρ = .49, P = .06).

CONCLUSIONS

FDMRI VDP generated in free-breathing asthmatic patients was correlated with static inspiratory breath-hold ³He MRI VDP but underestimated VDP relative to ³He MRI VDP. Although less sensitive to salbutamol and MCh, FDMRI VDP may be considered for asthma patient evaluations at centers without inhaled-gas MRI.

Use of MDCT to Assess the Results of Bronchial Thermoplasty

OBJECTIVE

The purpose of this study was to evaluate the use of MDCT to assess response to bronchial thermoplasty treatment for severe persistent asthma.

MATERIALS AND METHODS

MDCT data from 26 patients with severe persistent asthma who underwent imaging before and after bronchial thermoplasty were analyzed retrospectively. Changes in the following parameters were assessed: total lung volume, mean lung density, airway wall thickness, CT air trapping index (attenuation < -856 HU), and expiratory-inspiratory ratio of mean lung density (E/I index). Asthma Quality of Life Questionnaire score changes were also assessed.

RESULTS

Median total lung volumes before and after bronchial thermoplasty were 2668 mL (range, 2226-3096 mL) and 2399 mL (range, 1964-2802 mL; p = 0.08), respectively. Patients also showed a pattern of obstruction improvement in air trapping values (median before thermoplasty, 14.25%; median after thermoplasty, 3.65%; p < 0.001] and in mean lung density values ± SD (before thermoplasty, -702 ± 72 HU; after thermoplasty, -655 ± 66 HU; p < 0.01). Median airway wall thickness also decreased after bronchial thermoplasty (before thermoplasty, 1.5 mm; after thermoplasty, 1.1 mm; p < 0.05). There was a mean Asthma Quality of Life Questionnaire overall score change of 1.00 ± 1.35 (p < 0.001), indicating asthma clinical improvement.

CONCLUSION

Our study showed improvement in CT measurements after bronchial thermoplasty, along with Asthma Quality of Life Questionnaire score changes. Thus, MDCT could be useful for imaging evaluation of patients undergoing this treatment.

Small airways disease and severe asthma

The small airways of the lungs are commonly affected in pediatric and adult asthma. Small airways disease has been related to asthma control, severity, and risk of exacerbation. Diagnosis of small airways disease can be best made through evaluation of surgical lung specimens. Noninvasive techniques including spirometry, plethysmography, nitrogen washout, impulse oscillometry, and cross-sectional imaging have been utilized to assess and infer the extent of small airways disease in asthma and can be used longitudinally to assess response to treatment. Patients with small airways disease seem to benefit from inhaled asthma medications that have improved capacity to reach the distal lung compartment. This is especially important for patients with severe asthma, who rely upon high doses of inhaled corticosteroid and bronchodilators for asthma control. This review will describe the techniques which may be utilized to assess small airways disease, discuss the prevalence and characteristics of small airways disease in severe asthma, and highlight how small airway disease may complicate severe asthma treatment.

High resolution computed tomographic evaluation of bronchial wall thickness in healthy and clinically asthmatic cats

The objective of study is to determine the thickness of bronchial walls of clinically diagnosed asthmatic cats using high resolution computed tomography (HRCT) compared to that of healthy cats. The bronchial walls and pulmonary arteries were measured in healthy 16 cats and clinically asthmatic 4 cats. The bronchial walls and pulmonary arteries were measured under general anesthesia with positive pressure inspiration using HRCT. In healthy and asthmatic cats, bronchial lumen to the artery ratio (BA ratio), the ratio of bronchial wall thickness to bronchial diameter (TD ratio) and ratio of bronchial wall thickness to pulmonary artery (TA ratio) were measured. The mean BA ratio, TD ratio and TA ratio in healthy cats were 0.86 ± 0.12, 0.18 ± 0.02 and 0.25 ± 0.05, respectively. Under the same condition, the mean BA ratio, TD ratio and TA ratio in asthmatic cats were 0.93 ± 0.21, 0.22 ± 0.24 and 0.37 ± 0.06. The TD ratio and TA ratio in asthmatic cats were significantly higher than healthy cats (P<0.001). BA ratio was not significantly different in both groups (P>0.05). The evaluation of bronchial wall thickness by HRCT could be useful for diagnosis of disease of bronchial wall thickening, such as feline asthma.

CT features of normal lung change in asymptomatic elderly patients

Background

Not all morphological lung changes in the elderly contribute to respiratory disease and may be a consequence of normal aging.

Objectives

To describe the changes in asymptomatic elderly patients compared with those in younger patients in a Thai population.

Methods

The study cohort comprised 60 participants without respiratory symptoms in three groups of 20 by age: 20-40 years, 41-60 years, and >60 years. Participants were prospectively selected from patients referred for computed tomography (CT) of the abdomen, or head and neck, and underwent sequential CT during deep breathing at four lung levels. Two observers scored images by consensus. We compared groups using Pearson chi-square and Fisher exact tests, and used receiver operating characteristic curves to categorize bronchiectasis and bronchial wall thickening by age.

Results

Air trapping was related to age (5/20 group 1, 7/20 group 2, and 18/20 group 3 (P <0.01)) and was most prevalent in lower lobes (78%, P < 0.01). Reticulation was found in only one middle aged patient (P = 0.36). Bronchiectasis was more common in patients <56 years (7/23) than <56 years (3/37), P = 0.035. Bronchial wall thickening (7/23 in patients >56 years and 2/37 in patients <56 years, P = 0.02) and extensive air trapping were related to age (0/6 group 1, 1/6 group 2, and 5/6 group 3, P = 0.02). Findings were independent of smoking history.

Conclusions

Asymptomatic older patients had higher prevalence of bronchiectasis, bronchial wall thickening, and air trapping, independent of smoking history.

Biomarkers in the Management of Difficult Asthma

Difficult asthma is a heterogeneous disease of the airways including various types of bronchial inflammation and various degrees of airway remodeling. Therapeutic response of severe asthmatics can be predicted by the use of biomarkers of Type2-high or Type2-low inflammation. Based on sputum cell analysis, four inflammatory phenotypes have been described. As induced sputum is time-consuming and expensive technique, surrogate biomarkers are useful in clinical practice.

Eosinophilic phenotype is likely to reflect ongoing adaptive immunity in response to allergen. Several biomarkers of eosinophilic asthma are easily available in clinical practice (blood eosinophils, serum IgE, exhaled nitric oxyde, serum periostin). Neutrophilic asthma is thought to reflect innate immune system activation in response to pollutants or infectious agents while paucigranulocytic asthma is thought to be not inflammatory and characterized by smooth muscle dysfunction. We currently lack of user-friendly biomarkers of neutrophilic asthma and airway remodeling.

In this review, we summarize the biomarkers available for the management of difficult asthma.

Adiposity influences airway wall thickness and the asthma phenotype of HIV-associated obstructive lung disease: a cross-sectional study

Background

Airflow obstruction, which encompasses several phenotypes, is common among HIV-infected individuals. Obesity and adipose-related inflammation are associated with both COPD (fixed airflow obstruction) and asthma (reversible airflow obstruction) in HIV-uninfected persons, but the relationship to airway inflammation and airflow obstruction in HIV-infected persons is unknown. The objective of this study was to determine if adiposity and adipose-associated inflammation are associated with airway obstruction phenotypes in HIV-infected persons.

Methods

We performed a cross-sectional analysis of 121 HIV-infected individuals assessed with pulmonary function testing, chest CT scans for measures of airway wall thickness (wall area percent [WA%]) and adipose tissue volumes (mediastinal and subcutaneous), as well as HIV- and adipose-related inflammatory markers. Participants were defined as COPD phenotype (post-bronchodilator FEV₁/FVC < lower limit of normal) or asthma phenotype (doctor-diagnosed asthma or bronchodilator response). Pearson correlation coefficients were calculated between adipose measurements, WA%, and pulmonary function. Multivariable logistic and linear regression models were used to determine associations of airflow obstruction and airway remodeling (WA%) with adipose measurements and participant characteristics.

Results

Twenty-three (19 %) participants were classified as the COPD phenotype and 33 (27 %) were classified as the asthma phenotype. Body mass index (BMI) was similar between those with and without COPD, but higher in those with asthma compared to those without (mean [SD] 30.7 kg/m² [8.1] vs. 26.5 kg/m² [5.3], p = 0.008). WA% correlated with greater BMI (r = 0.55, p < 0.001) and volume of adipose tissue (subcutaneous, r = 0.40; p < 0.001; mediastinal, r = 0.25; p = 0.005). Multivariable regression found the COPD phenotype associated with greater age and pack-years smoking; the asthma phenotype with younger age, female gender, smoking history, and lower adiponectin levels; and greater WA% with greater BMI, younger age, higher soluble CD163, and higher CD4 counts.

Conclusions

Adiposity and adipose-related inflammation are associated with an asthma phenotype, but not a COPD phenotype, of obstructive lung disease in HIV-infected persons. Airway wall thickness is associated with adiposity and inflammation. Adipose-related inflammation may play a role in HIV-associated asthma.

CT Scan Does Not Differentiate Patients with Hepatopulmonary Syndrome from Other Patients with Liver Disease

Background

Hepatopulmonary syndrome (HPS) is defined by liver dysfunction, intrapulmonary vascular dilatations, and impaired oxygenation. The gold standard for detection of intrapulmonary vascular dilatations in HPS is contrast echocardiography. However, two small studies have suggested that patients with HPS have larger segmental pulmonary arterial diameters than both normal subjects and normoxemic subjects with cirrhosis, when measured by CT. We sought to compare CT imaging-based pulmonary vasodilatation in patients with HPS, patients with liver dysfunction without HPS, and matching controls on CT imaging.

Methods

We performed a retrospective cohort study at two quaternary care Canadian HPS centers. We analyzed CT thorax scans in 23 patients with HPS, 29 patients with liver dysfunction without HPS, and 52 gender- and age-matched controls. We measured the artery-bronchus ratios (ABRs) in upper and lower lung zones, calculated the “delta ABR” by subtracting the upper from the lower ABR, compared these measurements between groups, and correlated them with clinically relevant parameters (partial pressure of arterial oxygen, alveolar-arterial oxygen gradient, macroaggregated albumin shunt fraction, and diffusion capacity). We repeated measurements in patients with post-transplant CTs.

Results

Patients had significantly larger lower zone ABRs and delta ABRs than controls (1.20 +/- 0.19 versus 0.98 +/- 0.10, p<0.01; and 0.12 +/- 0.17 versus -0.06 +/- 0.10, p<0.01, respectively). However, there were no significant differences between liver disease patients with and without HPS, nor any significant correlations between CT measurements and clinically relevant parameters. There were no significant changes in ABRs after liver transplantation (14 patients).

Conclusions

Basilar segmental artery-bronchus ratios are larger in patients with liver disease than in normal controls, but this vasodilatation is no more severe in patients with HPS. CT does not distinguish patients with HPS from those with uncomplicated liver disease.

Comparison of endobronchial ultrasound and high resolution computed tomography as tools for airway wall imaging in asthma and chronic obstructive pulmonary disease

INTRODUCTION

Airway remodeling in asthma and chronic obstructive pulmonary disease (COPD) results in bronchial wall thickening. Bronchial wall thickness (BWT) can be assessed in high-resolution computed tomography (HRCT) and endobronchial ultrasound (EBUS).

AIMS

To compare BWT measured by EBUS and HRCT in patients with mild-to-moderate asthma and COPD, and to evaluate the relationship between the BWT and pulmonary function.

METHODS

The study included patients with mild-to-moderate asthma (n = 24), COPD (n = 36) and controls (n = 12). Bronchoscopy with EBUS (radial probe) and HRCT were performed to measure the BWT in the segmental bronchus.

RESULTS

Good overall agreement between EBUS and HRCT measurements of BWT was demonstrated. Median HRCT-BWT did not reveal any significant differences between individuals with asthma and COPD, and control subjects: 1.56 (1.27-1.70) mm, 1.62 (1.45-1.90) mm, and 1.63 (1.41-1.77) mm, respectively (p = 0.315). In contrast, median BWT measured by EBUS was significantly higher in asthma and COPD groups when compared to controls: 1.20 (1.02-1.41) mm, 1.19 (1.10-1.48) mm, and 0.99 (0.90-1.08) mm, respectively (p = 0.006). There were no differences in BWT in mild-to-moderate asthma and COPD or significant correlations between BWT and the results of pulmonary function tests.

CONCLUSIONS

The use of EBUS to assess BWT in asthma and COPD is feasible and it shows good compatibility with HRCT. A tendency towards lower BWT values in EBUS when compared to HRCT was observed. The finding that EBUS measurements demonstrated the differences between BWT in patients with obstructive lung diseases and controls, may suggest that EBUS is a more sensitive method to study the BWT than HRCT.

Clinical implications of mucosal remodeling from chronic rhinosinusitis

BACKGROUND

Prognostic implications of mucosal remodeling in chronic rhinosinusitis (CRS) remain unclear. Remodeling of respiratory mucosa in asthma is associated with greater medication use and decreased function. This study investigates the implications of mucosal remodeling on long-term clinical outcomes in patients with CRS.

METHODS

A case-control study of adult patients with CRS undergoing endoscopic sinus surgery (ESS) was performed. Mucosal remodeling was defined by squamous metaplasia, subepithelial fibrosis, and/or basement membrane thickening. The presence of remodeling changes were assessed relative to clinical and treatment outcomes at a minimum of 12 months postoperatively. Clinical outcomes were assessed at baseline and 12 months using a Nasal Symptom Score (NSS) and 22-item Sino-Nasal Outcome Test (SNOT-22). Treatment outcomes were assessed by oral corticosteroid usage (burst/continuous), topical corticosteroid irrigation frequency, and further surgical intervention.

RESULTS

A total of 110 patients (48.73 ± 14.75 years, 48.2% female) were assessed. Significant improvements where seen for the entire population, in both NSS (2.64 ± 1.06 to 1.34 ± 1.08, p < 0.001) and SNOT-22 (2.05 ± 0.96 to 1.06 ± 0.79, p < 0.001). Patients with remodeling (n = 88) were younger (47.2 ± 14.8 vs 54.7 ± 13.5 years, p = 0.03), but had similar symptom scores. Remodeling was seen in CRS with nasal polyposis (CRSwNP) (54.5%) and eosinophilic chronic rhinosinusitis (eCRS) (59.8%). Symptom improvement at 12 months was similar between remodeled and non-remodeled groups (NSS: Δ1.34 ± 1.20 vs Δ1.12 ± 1.31, p = 0.395; SNOT-22: Δ1.05 ± 0.91 vs Δ0.73 ± 0.95, p = 0.124); however, patients with remodeling had greater corticosteroid irrigation frequency (64.0% vs 31.6% daily use, Kendall's tau-b p = 0.004).

CONCLUSION

Established mucosal remodeling predicts a greater reliance on topical therapies to reach similar clinical endpoints as those without remodeling.

Quantitative computed tomography imaging of airway remodeling in severe asthma

Asthma is a heterogeneous condition and approximately 5-10% of asthmatic subjects have severe disease associated with structure changes of the airways (airway remodeling) that may develop over time or shortly after onset of disease. Quantitative computed tomography (QCT) imaging of the tracheobronchial tree and lung parenchyma has improved during the last 10 years, and has enabled investigators to study the large airway architecture in detail and assess indirectly the small airway structure. In severe asthmatics, morphologic changes in large airways, quantitatively assessed using 2D-3D airway registration and recent algorithms, are characterized by airway wall thickening, luminal narrowing and bronchial stenoses. Extent of expiratory gas trapping, quantitatively assessed using lung densitometry, may be used to assess indirectly small airway remodeling. Investigators have used these quantitative imaging techniques in order to attempt severity grading of asthma, and to identify clusters of asthmatic patients that differ in morphologic and functional characteristics. Although standardization of image analysis procedures needs to be improved, the identification of remodeling pattern in various phenotypes of severe asthma and the ability to relate airway structures to important clinical outcomes should help target treatment more effectively.

Interstitial changes in asthma-COPD overlap syndrome

INTRODUCTION

Asthma-COPD overlap syndrome (ACOS) is the widely recognized syndrome of asthma and COPD coexisting together. Cigarette smoking is a known risk factor for ACOS and is reported to be associated with interstitial lung diseases (ILDs). Subclinical ILDs have been frequently detected in smokers' lungs by radiological and pathological examinations. This finding raises the possibility that unrecognized mild interstitial changes take place in lungs with ACOS.

OBJECTIVES

We sought to determine whether interstitial changes were present in the lungs of patients with ACOS and to characterize the clinical features of ACOS with interstitial changes.

METHODS

Thirty patients with ACOS were enrolled in the study (26 men and 4 women, mean age 70.1 years). Interstitial changes in the lungs were estimated by high-resolution computed tomography (HRCT). Clinical findings and airway wall thickness on HRCT were assessed retrospectively and compared between ACOS patients with and without interstitial changes.

RESULTS

Interstitial changes were found in seven patients (23.3%) with ACOS who had HRCT. The age and smoking amount were significantly higher in ACOS with interstitial changes than in ACOS without interstitial changes. ACOS with interstitial changes tended to have a higher rate of fungal sensitisation. Multivariate analysis showed pack-years were significantly related to the presence of interstitial changes. Airway walls assessed by HRCT were significantly thicker in ACOS with interstitial changes than in ACOS without interstitial changes.

CONCLUSIONS

The ACOS patients with interstitial changes were heavier smokers and had thicker airway walls on HRCT compared to the ACOS patients without interstitial changes.

Effect of treatment with inhaled corticosteroid on serum periostin levels in asthma

BACKGROUND AND OBJECTIVE

Periostin is a biomarker of eosinophilic airway inflammation and may contribute to airway remodeling in asthma. The anti-inflammatory activity of inhaled corticosteroids (ICS) for asthma control is widely recognized. The aim of this study was to assess the effects of ICS on serum periostin levels and its relationships to inflammation and airway geometry.

METHODS

Forty-two healthy controls and 20 patients with steroid-naïve asthma before and after treatment with fluticasone propionate (800 μg/day for 16 weeks) were examined. Serum periostin, lung function and inflammatory cell counts in sputum were measured. Airway dimensions were determined by quantitative computed tomography (total area of the airway (Ao), wall area (WA), wall thickness (T) and percentage wall area (WA%) ).

RESULTS

Serum periostin concentrations were significantly higher in patients with asthma than in controls. Periostin levels were correlated with airway wall thickness and sputum eosinophilia and inversely correlated with airflow limitation in asthma. ICS significantly decreased serum periostin (P < 0.01), decreased WA corrected for body surface area (WA/BSA, P < 0.05), T/√BSA (P < 0.01) and WA% (P < 0.01), reduced the percentage of sputum eosinophils (P < 0.01) and improved airflow limitation. The decrease in serum periostin levels was associated with an increased per cent predicted forced expiratory volume in 1 s (r = -0.64, P < 0.01), decreased WA/BSA (r = 0.46, P < 0.05) and decreased sputum eosinophils (r = 0.71, P < 0.01).

CONCLUSION

Serum periostin levels respond partially to ICS and may reflect a reduction in airway inflammation and wall thickening in asthma.

Novel imaging approaches in adult asthma and their clinical potential

Currently, imaging in asthma is confined to chest radiography and CT. The emergence of new imaging techniques and tremendous improvement of existing imaging methods, primarily due to technological advancement, has completely changed its research and clinical prospects. In research, imaging in asthma is now being employed to provide quantitative assessment of morphology, function and pathogenic processes at the molecular level. The unique ability of imaging for non-invasive, repeated, quantitative, and in vivo assessment of structure and function in asthma could lead to identification of 'imaging biomarkers' with potential as outcome measures in future clinical trials. Emerging imaging techniques and their utility in the research and clinical setting is discussed in this review.

Computed tomographic assessment of airflow obstruction in smoke inhalation injury: Relationship with the development of pneumonia and injury severity

PURPOSE

The prediction of pulmonary deterioration in patients with smoke inhalation injury is important because this influences the strategy for patient management. We hypothesized that narrowing of the luminal bronchus due to bronchial wall thickening correlates to respiratory deterioration in smoke inhalation injury patients.

METHODS

In a prospective observational study, all patients were enrolled at a single tertiary trauma and critical care center. In 40 patients, chest computed tomographic images were obtained within a few hours after smoke inhalation injury. We assessed bronchial wall thickness and luminal area % on chest computed tomographic images. Airway wall thickness to total bronchial diameter (T/D) ratio, percentage of luminal area, and clinical indices were compared between patients with smoke inhalation injury and control patients.

RESULTS

The T/D ratio of patients with smoke inhalation was significantly higher than that of control patients (p<0.001), and the luminal area of these patients was significantly smaller than that of control patients (p<0.001). The number of mechanical ventilation days correlated with the initial infusion volume, T/D ratio, and luminal area %. ROC analysis showed a cut-off value of 0.26 for the T/D ratio, with a sensitivity of 79.0% and specificity of 73.7%, and a value of 23.4% for luminal area %, with a sensitivity of 68.4% and specificity of 84.2%.

CONCLUSIONS

These data revealed the utility of computed tomography scanning on admission to show that the patients with smoke inhalation injury had airway wall thickening compared to control patients without smoke inhalation injury. Airflow narrowing due to airway wall thickening was related to the development of pneumonia and the number of mechanical ventilation days in patients with smoke inhalation injury. Airflow narrowing is one important factor of respiratory deterioration in smoke inhalation injury.

The Three A's in Asthma - Airway Smooth Muscle, Airway Remodeling & Angiogenesis

Asthma affects more than 300 million people worldwide and its prevalence is still rising. Acute asthma attacks are characterized by severe symptoms such as breathlessness, wheezing, tightness of the chest, and coughing, which may lead to hospitalization or death. Besides the acute symptoms, asthma is characterized by persistent airway inflammation and airway wall remodeling. The term airway wall remodeling summarizes the structural changes in the airway wall: epithelial cell shedding, goblet cell hyperplasia, hyperplasia and hypertrophy of the airway smooth muscle (ASM) bundles, basement membrane thickening and increased vascular density. Airway wall remodeling starts early in the pathogenesis of asthma and today it is suggested that remodeling is a prerequisite for other asthma pathologies. The beneficial effect of bronchial thermoplasty in reducing asthma symptoms, together with the increased potential of ASM cells of asthmatics to produce inflammatory and angiogenic factors, indicate that the ASM cell is a major effector cell in the pathology of asthma. In the present review we discuss the ASM cell and its role in airway wall remodeling and angiogenesis.