The epidemiology, etiology, clinical features, and natural history of emphysema

Automated evaluation of diaphragm configuration based on chest CT in COPD patients

BACKGROUND

Severe chronic obstructive pulmonary disease (COPD) often results in hyperinflation and flattening of the diaphragm. An automated computed tomography (CT)-based tool for quantifying diaphragm configuration, a biomarker for COPD, was developed in-house and tested in a large cohort of COPD patients.

METHODS

We used the LungQ platform to extract the lung-diaphragm intersection, as direct diaphragm segmentation is challenging. The tool computed the diaphragm index (surface area/projected surface area) as a measure of diaphragm configuration on inspiratory scans in a COPDGene subcohort. Visual inspection of 250 randomly selected segmentations served as a quality check. Associations between the diaphragm index, Global Initiative for Chronic Obstructive Lung Disease (GOLD) stages, forced expiratory volume in 1 s (FEV1) % predicted, and CT-derived emphysema scores were explored using analysis of variance and Pearson correlation.

RESULTS

The tool yielded incomplete segmentation in 9.2% (2.4% major defect, 6.8% minor defect) of 250 randomly selected cases. In 8431 COPDGene subjects (4240 healthy; 4191 COPD), the diaphragm index was increasingly lower with higher GOLD stages (never-smoked 1.83 ± 0.16; GOLD-0 1.79 ± 0.18; GOLD-1 1.71 ± 0.15; GOLD-2: 1.67 ± 0.16; GOLD-3 1.58 ± 0.14; GOLD-4 1.54 ± 0.11) (p < 0.001). Associations were found between the diaphragm index and both FEV1% predicted (r = 0.44, p < 0.001) and emphysema score (r = -0.36, p < 0.001).

CONCLUSION

We developed an automated tool to quantify the diaphragm configuration in chest CT. The diaphragm index was associated with COPD severity, FEV1%predicted, and emphysema score.

RELEVANCE STATEMENT

Due to the hypothesized relationship between diaphragm dysfunction and diaphragm configuration in COPD patients, automatic quantification of diaphragm configuration may prove useful in evaluating treatment efficacy in terms of lung volume reduction.

KEY POINTS

Severe COPD changes diaphragm configuration to a flattened state, impeding function. An automated tool quantified diaphragm configuration on chest-CT providing a diaphragm index. The diaphragm index was correlated to COPD severity and may aid treatment assessment.

Is Type and Grade of Emphysema Important for Bone Mineral Density and Aortic Calcifications?

Background: Chronic obstructive pulmonary disease has extrapulmonary manifestations, such as cardiovascular diseases and osteoporosis. The purpose of this research was to determine the relationship between the type and extent of emphysema with thoracic aorta calcification (TAC) and bone mineral density (BMD) at Th4, Th8, and L1 vertebrae. Methods: Emphysema was described by computed tomography parameters (both Fleischner classification and low attenuation value percentage, LAV%) and the clinical FEV1/FVC ratio (Tiffeneau-Pinelli index, TI, TI < 0.7; TI > 0.7). Results: Of 200 included patients (median age 64, 33% women), signs of clinical obstruction (TI) were observed in 104 patients, which had significantly lower BMD and more heavy TAC. BMD correlated negatively with LAV%, Rho = -0.16 to -0.23, while a positive correlation of aortic calcification with LAV% was observed, Rho = 0.30 to 0.33. Multiple linear regression showed that age and TI < 0.7 were independent predictors of BMD, β = -0.20 to -0.40, and β = -0.21 to -0.25; age and hypercholesterolemia were independent predictors of TCA, β = 0.61 and β = 0.19. Conclusions: Clinical TI and morphological LAV% parameters correlated with BMD and TAC, in contrast to Fleischer-graded emphysema, which showed no correlation. However, only TI was an independent predictor of BMD, while the morphologically described type and extent of emphysema could not independently predict any extrapulmonary manifestation.

Quantitative Computed Tomography Analysis of the Longitudinal Change Between Centrilobular and Paraseptal Emphysema Subtypes: A Retrospective Study

OBJECTIVE

This study aimed to investigate the difference between the extent of centrilobular emphysema (CLE) and paraseptal emphysema (PSE) on follow-up chest CT scans and their relationship to the cross-sectional area (CSA) of small pulmonary vessels.

METHODS

Sixty-two patients (36 CLE and 26 PSE) who underwent 2 chest CT scans were enrolled in this study. The percentage of low attenuation volume (%LAV) and total CSA of the small pulmonary vessels <5 mm 2 (%CSA < 5) were measured at the 2 time points. Analysis of the initial %CSA < 5 and the change in the %LAV and %CSA < 5 on follow-up imaging was performed.

RESULTS

The initial %CSA < 5 was not significantly different between the CLE and the PSE groups (CLE, 0.66 vs. PSE, 0.71; P = 0.78). There was no significant difference in the longitudinal change in the %LAV between the 2 groups (CLE, -0.048% vs. PSE, 0.005%; P = 0.26). The longitudinal change in the %CSA < 5 in patients with PSE significantly decreased compared with those with CLE (CLE, 0.025% vs. PSE, -0.018%; P = 0.02).

CONCLUSIONS

The longitudinal change in the %CSA < 5 was significantly different for patients with CLE and PSE, demonstrating an important pathophysiological difference between the subtypes.

The effects of lipoic acid on respiratory diseases

Respiratory diseases, including lung cancer, pulmonary fibrosis, asthma, and the recently emerging fatal coronavirus disease-19 (COVID-19), are the leading causes of illness and death worldwide. The increasing incidence and mortality rates have attracted much attention to the prevention and treatment of these conditions. Lipoic acid (LA), a naturally occurring organosulfur compound, is not only essential for mitochondrial aerobic metabolism but also shows therapeutic potential via certain pharmacological effects (e.g., antioxidative and anti-inflammatory effects). In recent years, accumulating evidence (animal experiments and in vitro studies) has suggested a role of LA in ameliorating many respiratory diseases (e.g., lung cancer, fibrosis, asthma, acute lung injury and smoking-induced lung injury). Therefore, this review will provide an overview of the present investigational evidence on the therapeutic effect of LA against respiratory diseases in vitro and in vivo. We also summarize the corresponding mechanisms of action to inspire further basic studies and clinical trials to confirm the health benefits of LA in the context of respiratory diseases.

Cost-effectiveness analysis of surgical lung volume reduction compared with endobronchial valve treatment in patients with severe emphysema

BACKGROUND

Lung volume reduction, either by surgery or bronchoscopically by endobronchial valve treatment have been shown to be a cost-effective alternative compared with conservative therapy. However, there is no comparative analysis of lung volume reduction by surgery and bronchoscopic lung volume reduction using endobronchial valves.

OBJECTIVES

The aim of this retrospective study was to provide a cost-effectiveness analysis of lung volume reduction by surgery compared with bronchoscopic lung volume reduction using endobronchial valves.

METHODS

The effectiveness of lung volume reduction was assessed using forced expiratory volume in the first second (FEV1), residual volume (RV) and 6-minute walking distance (6MWD), measured at baseline and at 4 to 12 weeks. Cost unit accounting derived from SwissDRG was used as a surrogate of the costs from the payer's perspective.

RESULTS

In total, 67 patients (37 men and 30 women) with a mean age of 68.3 ± 7.4 years were included. Both clinical effectiveness and costs were comparable between surgical and bronchoscopic lung reduction. The incremental cost-effectiveness ratios (ICERs) for bronchoscopic compared with lung volume reduction by surgery for FEV1, RV and 6MWD were -101, 4 and 58, respectively. For RV and 6MWD, it could be shown that endobronchial valve treatment is justified as a probably cost-effective alternative to lung volume reduction by surgery. Endobronchial valve treatment resulted in an improvement of 0.25 quality-adjusted life years (QALYs) and an ICER of € 7657 per QALY gained.

CONCLUSION

A robust statement on the superiority of one of the two procedures in terms of cost-effectiveness cannot be made from the present study. Therefore, the study is not suitable for resource allocation. Two upcoming trials comparing lung volume reduction surgery and endobronchial valve treatment may be able to answer this question.

Bronchoscopic Lung Volume Reduction Coil Treatment for Severe Emphysema: A Systematic Review and Meta-Analysis of Individual Participant Data

Background

Lung volume reduction coil (LVR-coil) treatment provides a minimally invasive treatment option for severe emphysema patients which has been studied in multiple clinical trials.

Objectives

The aim of the study was to assess the effect of LVR-coil treatment on pulmonary function, quality of life, and exercise capacity using individual participant data.

Method

PubMed, Web of Science, and EMBASE were searched until May 17, 2021. Prospective single-arm and randomized controlled trials that evaluated the effect of LVR-coil treatment on forced expiratory volume in 1 s (FEV₁), residual volume (RV), St. George Respiratory Questionnaire (SGRQ) total score, and/or 6-min walk distance (6MWD) and were registered in an official clinical trial database were eligible for inclusion. Individual patient data were requested, and a linear mixed effects model was used to calculate overall treatment effects.

Results

Eight trials were included in the final analysis, representing 680 individual patients. LVR-coil treatment resulted in a significant improvement in FEV1 at 3- (0.09 L [95% confidence interval (95% CI): 0.06–0.12]) and 6-month follow-up (0.07 L [95% CI: 0.03–0.10]), a significant reduction in RV at 3- (−0.45L [95% CI: −0.62 to −0.28]), 6- (−0.33L [95% CI: −0.52 to −0.14]), and 12-month follow-up (−0.36L [95% CI: −0.64 to −0.08]), a significant reduction in SGRQ total score at 3- (−12.3 points [95% CI: −15.8 to −8.8]), 6- (−10.1 points [95% CI: −12.8 to −7.3]), and 12-month follow-up (−9.8 points [95% CI: −15.0 to −4.7]) and a significant increase in 6MWD at 3-month follow-up (38 m [95% CI: 18–58]).

Conclusions

LVR-coil treatment in emphysema patients results in sustained improvements in pulmonary function and quality of life and shorter lived improvements in exercise capacity. Since the owner of this LVR-coil has decided to stop the production and newer generations LVR-coils are currently being developed, these results can act as a reference for future studies and clinical guidance.

Endobronchial treatment of severe asthma and severe emphysema with hyperinflation

PURPOSE OF REVIEW

The field of interventional pulmonology has ushered in a wave of innovations for individuals with obstructive airways disease in whom established medical therapies have failed. Leading the charge are bronchial thermoplasty for severe refractory asthma and uni-directional valves for severe emphysema with hyperinflation: both have received regulatory approvals in the United Kingdom and United States. With the commissioning of these novel treatments comes new challenges relating to implementation, positioning within therapeutic algorithms, honing of patient selection, and establishing long-term safety and benefits beyond 5 years.

RECENT FINDINGS

This review summarises the evidence for their safety and efficacy, predictors of therapeutic response, mechanism(s) of action and emerging data supporting the durability of outcomes out to at least ten years.

SUMMARY

It is anticipated the experience of treating increasing numbers of patients, the adoption of international registries, and ongoing research evaluations will serve to optimise these therapies for future generations of patients.

Predicting Respiratory Complications Following Lobectomy Using Quantitative CT Measures of Emphysema

Purpose

In performing surgery for lung cancer, emphysema is a risk factor related to postoperative respiratory complications (PRC). However, few studies have addressed the risk of radiological emphysematous volume affecting PRC. The aim of this study was to investigate the relationship between emphysematous volume as measured on 3-dimensional computed tomography and PRC.

Patients and Methods

We reviewed 342 lung cancer patients undergoing lobectomy between 2013 and 2018. The percentage of low attenuation area (LAA%) was defined as the percentage of the lung area showing attenuation of −950 Hounsfield units or lower. Preoperative factors including age, sex, body mass index, smoking index, respiratory function, tumour histology, and LAA% were evaluated. PRC included pneumonia, atelectasis, prolonged air leakage, empyema, hypoxia, ischemic bronchitis, bronchopleural fistula, and exacerbation of interstitial pneumonia. Uni- and multivariable analyses were performed to investigate the relationship between independent clinical variables and postoperative adverse events.

Results

Median LAA% was 5.0% (range, 0–40%) and PRC was observed in 50 patients (14.6%). Patients who presented with PRC showed significantly high LAA% compared to those without complications (median: 8.1% vs 3.8%; p < 0.001). Based on univariable analysis, age, sex, smoking index, percentage of forced expiratory volume in 1 s (FEV_1.0%), histology, and LAA% were significant predictors for PRC. Multivariable analysis revealed higher LAA% as a significant risk factor for PRC (odds ratio = 1.040; 95% confidence interval, 1.001–1.080; p = 0.046).

Conclusion

In addition to respiratory function with spirometry, LAA% can be used as a predictor of PRC.

Identifying Responders and Exploring Mechanisms of Action of the Endobronchial Coil Treatment for Emphysema

BACKGROUND

So far, 3 randomized controlled trials have shown that the endobronchial treatment using coils is safe and effective. However, the more exact underlying mechanism of the treatment and best predictors of response are unknown.

OBJECTIVES

The aim of the study was to gain more knowledge about the underlying physiological mechanism of the lung volume reduction coil treatment and to identify potential predictors of response to this treatment.

METHODS

This was a prospective nonrandomized single-center study which included patients who were bilaterally treated with coils. Patients underwent an extensive number of physical tests at baseline and 3 months after treatment.

RESULTS

Twenty-four patients (29% male, mean age 62 years, forced expiratory volume in 1 s [FEV1] 26% pred, residual volume (RV) 231% pred) were included. Three months after treatment, significant improvements were found in spirometry, static hyperinflation, air trapping, airway resistance, treated lobe RV and treated lobes air trapping measured on CT scan, exercise capacity, and quality of life. The change in RV and airway resistance was significantly associated with a change in FEV1, forced vital capacity, air trapping, maximal expiratory pressure, dynamic compliance, and dynamic hyperinflation. Predictors of treatment response at baseline were a higher RV, larger air trapping, higher emphysema score in the treated lobes, and a lower physical activity level.

CONCLUSIONS

Our results confirm that emphysema patients benefit from endobronchial coil treatment. The primary mechanism of action is decreasing static hyperinflation with improvement of airway resistance which consequently changes dynamic lung mechanics. However, the right patient population needs to be selected for the treatment to be beneficial which should include patients with severe lung hyperinflation, severe air trapping, and significant emphysema in target lobes.

ADAM17 Deficiency Protects against Pulmonary Emphysema

Pulmonary emphysema is the major debilitating component of chronic obstructive pulmonary disease (COPD), which is a leading cause of morbidity and mortality worldwide. The ADAM17 (A disintegrin and metalloproteinase 17) protease mediates inflammation via ectodomain shedding of numerous proinflammatory cytokines, cytokine receptors, and adhesion molecules; however, its role in the pathogenesis of emphysema and COPD is poorly understood. This study aims to define the role of the protease ADAM17 in the pathogenesis of pulmonary emphysema. ADAM17 protein expression and activation was investigated in lung biopsies from patients with emphysema, as well as lungs of the emphysematous gp130F/F mouse model and an acute (4 d) cigarette smoke (CS)-induced lung pathology model. The Adam17ex/ex mice, which display significantly reduced global ADAM17 expression, were coupled with emphysema-prone gp130F/F mice to produce gp130F/F:Adam17ex/ex. Both Adam17ex/ex and wild-type mice were subjected to acute CS exposure. Histological, immunohistochemical, immunofluorescence, and molecular analyses as well as lung function tests were performed to assess pulmonary emphysema, inflammation, and alveolar cell apoptosis. ADAM17 was hyperphosphorylated in the lungs of patients with emphysema and also in emphysematous gp130F/F and CS-exposed mice. ADAM17 deficiency ameliorated the development of pulmonary emphysema in gp130F/F mice by suppressing elevated alveolar cell apoptosis. In addition, genetic blockade of ADAM17 protected mice from CS-induced pulmonary inflammation and alveolar cell apoptosis. Our study places the protease ADAM17 as a central molecular switch implicated in the development of pulmonary emphysema, which paves the way for using ADAM17 inhibitors as potential therapeutic agents to treat COPD and emphysema.

Analysis of lung volume reduction surgery results with video-assisted thoracoscopic surgery in emphysematous lung patients

AIM

In our study, we aimed to evaluate the results of patients who underwent lung volume reduction surgery with video-assisted thoracoscopic surgery due to diffuse or upper lobe limited emphysema.

MATERIAL AND METHODS

Patients who underwent lung volume reduction surgery (LVRS) for emphysema in our clinic between March 2015 and January 2020 were included in the study. The files of the patients were evaluated retrospectively. Age, gender, smoking history, hospitalization time, drain removal time, complications, and postoperative pulmonary function test values were evaluated in the patient records.

RESULTS

Twenty-four of the patients were male and 2 were female. The average age was determined as 49.6. Twenty-six patients underwent 31 surgical procedures, 5 of which were bilateral. Twenty-seven of them were performed by videothoracoscopic LVRS. Preoperative mean forced expiratory volume in 1 s (FEV1) value was 32.7%, total lung capacity 132%, residual volume 280%. The average length of hospital stay was found to be 7.75 days (4-19), and the time to remove the thorax drain was 9.5 (4-23) days. FEV1: 1.78 (48.5%) was found in the pulmonary function tests of the patients at the 6th month postoperative controls. According to preoperative FEV1, 48.3% improvement was detected.

CONCLUSIONS

Volume reduction surgery is a treatment method that positively affects the natural course of emphysema in addition to quitting smoking and oxygen therapy. Patients with predominantly emphysema in the upper lobes, low exercise capacity, and appropriate FEV1 values benefited most from this treatment.

Lung Volume Reduction in Pulmonary Emphysema

Severe emphysema with hyperinflation presents a therapeutic challenge. Inhaled medication has limited efficacy in individuals with mechanical constraints to the respiratory pump and impaired gas exchange. Lung volume reduction surgery (LVRS) reestablishes some semblance of normal physiology, resecting grossly expanded severely diseased tissue to restore the function of compromised relatively healthy lung, and has been shown to significantly improve exercise capacity, quality of life, and survival, especially in individuals with upper-lobe predominant emphysema and low-baseline exercise capacity, albeit with higher early morbidity and mortality. Bronchoscopic lung volume reduction achieved by deflating nonfunctioning parts of the lung is promoted as a less invasive and safer approach. Endobronchial valve implantation has demonstrated comparable outcomes to LVRS in selected individuals and has recently received approvals by the National Institute of Clinical Excellence in the United Kingdom and the Food and Drug Administration in the United States of America. Endobronchial coils are proving a viable treatment option in severe hyperinflation in the presence of collateral ventilation in selected cases of homogeneous disease. Modalities including vapor and sealant are delivered using a segmental strategy preserving healthier tissue within the same target lobe-efficacy and safety-data are, however, limited. This article will review the data supporting these novel technologies.

Emphysema - The review of radiological presentation and its clinical impact in the LDCT screening era

Emphysema is one of three main lung pathologies in Chronic Obstructive Pulmonary Disease, along with chronic bronchitis and small airway obstruction. The diagnosis is based on detection of low attenuation areas in lung tissue on chest Computed Tomography, either visual by a radiologist, or automatic by the applied Computed Tomography software. Results of the studies on the association between emphysema and lung cancer incidence are mixed. Many studies have demonstrated, that chronic lung diseases, like Chronic Obstructive Pulmonary Disease, are associated with lung cancer morbidity. There is also evidence, that emphysema can be related with worse prognosis in patients with detected lung cancer. In this review article we aim to summarize current knowledge about emphysema detection and evaluation on Computed Tomography, both quantitative and qualitative. We also summarize current data on correlation between emphysema and lung cancer, as well as its potential use in selecting patients, who would most benefit from lung cancer screening.

Bronchoscopic interventions for severe emphysema: Where are we now?

Patients with severe emphysema have limited treatment options and only derive a small benefit from optimal medical treatment. The only other therapy to have significant clinical beneficial effect in emphysema is LVRS but the perceived risk and invasiveness of surgery has fuelled bronchoscopic approaches to induce lung volume reduction. There are multiple bronchoscopic methods for achieving volume reduction in severe emphysema: EBV, airway bypass procedure, endobronchial coils, thermal (vapour) sclerosis and chemical sclerosis (sealants). Optimal patient selection is key to successful patient outcomes. This review discusses bronchoscopic approaches for emphysema treatment which has progressed through clinical trials to clinical practice.

Bronchoscopic lung volume reduction using an endobronchial valve to treat a huge emphysematous bullae: a case report

BACKGROUND

In patients with chronic obstructive pulmonary disease (COPD), bronchoscopic lung volume reduction (BLVR) techniques using unidirectional endobronchial valves improve lung function and increase exercise tolerance. BLVR treatment is included in the Global Initiative for Chronic Obstructive Lung Disease (GOLD) treatment guidelines for COPD patients without interlobar collateral ventilation. However, BLVR using an endobronchial valve has not been attempted in patients with giant bullae.

CASE PRESENTATION

We report successful and safe BLVR using an endobronchial valve in a patient with a huge bullous emphysema in the right middle lobe. A 65-year-old male was diagnosed with COPD 5 years prior and had a large bullae in the right middle lobe at that time. During regular follow-up, the symptoms of respiratory distress gradually worsened, and the size of the bullae gradually increased on computed tomography (CT). Therefore, we decided to treat the patient via BLVR using an unidirectional endobronchial valve. The Chartis system (Pulmonx, Inc., Palo Alto, CA) confirmed the absence of collateral ventilation of the right middle lobe. We successfully inserted an endobronchial valve into the right middle bronchus. After insertion, the bullae decreased dramatically in size, and the patient's symptoms and quality of life improved markedly.

CONCLUSION

This case supports recent suggestions that BLVR can serve as a good alternative treatment for appropriately selected patients.

Bronchoscopic Lung Volume Reduction

Since the publication of the National Emphysema Treatment Trial study, lung volume reduction (LVR) has been considered a therapeutic alternative for patients with advanced obstructive lung disease. The high complication rate of surgical LVR has led to the development of bronchoscopic LVR (BLVR). Of the currently available BLVR alternatives, coils and unidirectional endobronchial valves lead the list. The choice of each device depends on emphysema characteristics and presence of collateral ventilation. Evaluation of these patients at centers with expertise in interventional pulmonology and management of BLVR is strongly recommended.

The Aryl Hydrocarbon Receptor and the Maintenance of Lung Health

Much of what is known about the Aryl Hydrocarbon Receptor (AhR) centers on its ability to mediate the deleterious effects of the environmental toxicant 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD; dioxin). However, the AhR is both ubiquitously-expressed and evolutionarily-conserved, suggesting that it evolved for purposes beyond strictly mediating responses to man-made environmental toxicants. There is growing evidence that the AhR is required for the maintenance of health, as it is implicated in physiological processes such as xenobiotic metabolism, organ development and immunity. Dysregulation of AhR expression and activity is also associated with a variety of disease states, particularly those at barrier organs such as the skin, gut and lungs. The lungs are particularly vulnerable to inhaled toxicants such as cigarette smoke. However, the role of the AhR in diseases such as chronic obstructive pulmonary disease (COPD)-a respiratory illness caused predominately by cigarette smoking-and lung cancer remains largely unexplored. This review will discuss the growing body of literature that provides evidence that the AhR protects the lungs against the damaging effects of cigarette smoke.

Pulmonary Emphysema Cross-Linking with Pulmonary Fibrosis and Vice Versa: a Non-usual Experimental Intervention with Elastase and Bleomycin

Elastase (PPE) is usually used for emphysema models, whereas bleomycin (BLM) is used for fibrosis models. The aim of this study was to investigate the effect of BLM in PPE-induced emphysema, as well as the effect of PPE in BLM-induced fibrosis. C57BL/6 mice were divided into five groups: control, PPE, BLM, PPE + BLM, and BLM + PPE. Mice received saline, PPE (3 U/mouse), or BLM (20 U/kg) by intranasal instillation. Mice from the BLM and BLM + PPE groups received BLM on day 0 and saline or PPE on day 21, respectively. Those in the PPE and PPE + BLM groups received PPE on day 0 and saline or BLM on day 21, respectively. Mice were euthanized on day 42. We performed histology, morphometry in lung sections and ELISA, zymography and western blotting in BAL samples or lung homogenates. In the lungs of PPE + BLM and BLM + PPE groups, we observed inflammation, oxidative stress and expression of MMP-2 and MMP-9. The alveolar enlargement was reduced in the PPE + BLM group, suggesting that the BLM could participate in the alveolar remodeling process. The significance of this result supports future therapeutic approaches targeting extracellular-matrix deposition in patients with emphysema as a way to repair the enlargement of alveoli and airspaces.

Bronchoscopic Lung Volume Reduction: A 2018 Review and Update

Bronchoscopic lung volume reduction (BLVR) procedure has expanded the treatment spectrum of patients with end-stage emphysema. These treatments include valve, coil, thermal vapor ablation, bio-lung volume reduction, targeted lung denervation, and airway bypass stent. This short review provides an up-to-date information on BLVR treatments, their clinical benefits, and an overview of complications. BLVR treatments generally affect dyspnea by reducing hyperinflation and residual volume (RV). Benefits of treatment are associated with improvement in lung function parameters (forced expiration volume in the first second, total lung capacity, RV, and 6-minute walking test) and quality of life. Serious potential pulmonary complications, such as pneumothorax, pneumonia, respiratory failure, and chronic obstructive pulmonary disease exacerbation, may also occur after BLVR treatment. In addition to these, low-cost BLVR methods, such as autologous blood and fibrin glue, are in the developmental stage. Bronchoscopic lung volume reduction treatments are a promising method with positive results for patients with severe emphysema. The widespread use of these techniques, inadequate selection of patients, and non-critical and, therefore, unsuccessful use of BLVR in non-specialist centers lead to a false negative impression of the effectiveness of these techniques. In addition to these considerations, it is obvious that these treatments, which are quite expensive, are burdening social health systems. The reduction of costs or the development of lower-cost treatment methods is important for the future and for the availability of treatments.

Coils for the Treatment of Advanced Emphysema: A Growing Body of Evidence and Routine Experience

Endoscopic lung volume reduction (ELVR) mainly comprises endobronchial valves (EBV) and endobronchial coil (EBC) implants. EBV aims to occlude the most diseased and/or hyperinflated lobe thus inducing complete atelectasis. EBC therapy was developed a few years ago and is applicable independently of collateral flow and in patients presenting with disease dispersed throughout the upper and lower lobes. Bronchoscopic lung volume reduction with EBC is feasible in a wider range of patients (irrespective of collateral flow or disease homo/heterogeneity) than for EBV, and provides clinical benefits in the short-term, associated to an acceptable safety profile. The growing clinical and commercial experience of ELVR with nitinol coils will be reviewed in this article.

Lung volume reduction for emphysema

Advanced emphysema is a lung disease in which alveolar capillary units are destroyed and supporting tissue is lost. The combined effect of reduced gas exchange and changes in airway dynamics impairs expiratory airflow and leads to progressive air trapping. Pharmacological therapies have limited effects. Surgical resection of the most destroyed sections of the lung can improve pulmonary function and exercise capacity but its benefit is tempered by significant morbidity. This issue stimulated a search for novel approaches to lung volume reduction. Alternative minimally invasive approaches using bronchoscopic techniques including valves, coils, vapour thermal ablation, and sclerosant agents have been at the forefront of these developments. Insertion of endobronchial valves in selected patients could have benefits that are comparable with lung volume reduction surgery. Endobronchial coils might have a role in the treatment of patients with emphysema with severe hyperinflation and less parenchymal destruction. Use of vapour thermal energy or a sclerosant might allow focal treatment but the unpredictability of the inflammatory response limits their current use. In this Review, we aim to summarise clinical trial evidence on lung volume reduction and provide guidance on patient selection for available therapies.

Status of and prospects for bronchoscopic lung volume reduction for patients with severe emphysema

Bronchoscopic lung volume reduction (BLVR) is a minimally invasive treatment for severe emphysema, providing treatment options for patients who are unable to undergo lung volume reduction surgery (LVRS) or lung transplantation. Current BLVR techniques include bronchoscopic volume reduction with valve implants, use of a lung volume reduction coil (LVRC), bronchoscopic thermal vapor ablation (BTVA), biological lung volume reduction (BioLVR), and use of airway bypass stents (ABS). To date, several randomized controlled trials of these bronchoscopic therapies have been conducted in patients with emphysema, and bronchoscopic volume reduction with valve implants remains the best approach thus far. Recent studies indicate that BLVR may be of great value in improving lung function, exercise capacity, and quality of life and that BLVR has the potential to replace conventional surgery for patients with severe emphysema. Optimal patient selection and the proper selection of the BLVR technique in accordance with patient characteristics are crucial to the success of BLVR. More multicenter, prospective, randomized controlled trials need to be conducted in the future to optimize the current selection strategy and evaluate the safety, efficiency, and long-term benefit of BLVR techniques.

Genome-wide study of percent emphysema on computed tomography in the general population. The Multi-Ethnic Study of Atherosclerosis Lung/SNP Health Association Resource Study

RATIONALE

Pulmonary emphysema overlaps partially with spirometrically defined chronic obstructive pulmonary disease and is heritable, with moderately high familial clustering.

OBJECTIVES

To complete a genome-wide association study (GWAS) for the percentage of emphysema-like lung on computed tomography in the Multi-Ethnic Study of Atherosclerosis (MESA) Lung/SNP Health Association Resource (SHARe) Study, a large, population-based cohort in the United States.

METHODS

We determined percent emphysema and upper-lower lobe ratio in emphysema defined by lung regions less than -950 HU on cardiac scans. Genetic analyses were reported combined across four race/ethnic groups: non-Hispanic white (n = 2,587), African American (n = 2,510), Hispanic (n = 2,113), and Chinese (n = 704) and stratified by race and ethnicity.

MEASUREMENTS AND MAIN RESULTS

Among 7,914 participants, we identified regions at genome-wide significance for percent emphysema in or near SNRPF (rs7957346; P = 2.2 × 10(-8)) and PPT2 (rs10947233; P = 3.2 × 10(-8)), both of which replicated in an additional 6,023 individuals of European ancestry. Both single-nucleotide polymorphisms were previously implicated as genes influencing lung function, and analyses including lung function revealed independent associations for percent emphysema. Among Hispanics, we identified a genetic locus for upper-lower lobe ratio near the α-mannosidase-related gene MAN2B1 (rs10411619; P = 1.1 × 10(-9); minor allele frequency [MAF], 4.4%). Among Chinese, we identified single-nucleotide polymorphisms associated with upper-lower lobe ratio near DHX15 (rs7698250; P = 1.8 × 10(-10); MAF, 2.7%) and MGAT5B (rs7221059; P = 2.7 × 10(-8); MAF, 2.6%), which acts on α-linked mannose. Among African Americans, a locus near a third α-mannosidase-related gene, MAN1C1 (rs12130495; P = 9.9 × 10(-6); MAF, 13.3%) was associated with percent emphysema.

CONCLUSIONS

Our results suggest that some genes previously identified as influencing lung function are independently associated with emphysema rather than lung function, and that genes related to α-mannosidase may influence risk of emphysema.

Novel low molecular weight lignins as potential anti-emphysema agents: In vitro triple inhibitory activity against elastase, oxidation and inflammation

No molecule has been found to be effective against emphysema to date primarily because of its complex pathogenesis that involves elastolysis, oxidation and inflammation. We here describe novel unsulfated or sulfated low molecular weight lignins (LMWLs) chemo-enzymatically prepared from 4-hydroxycinnamic acids monomers, as the first potent triple-action inhibitors of neutrophil elastase, oxidation and inflammation. The inhibitory potencies of three different cinnamic acid-based LMWLs were determined in vitro using chromogenic substrate hydrolysis assays, radical scavenging and lung cellular oxidative biomarker reduced glutathione (rGSH) assays, and lung cellular inflammatory biomarker NFκB and IL-8 assays, respectively. Each LWML uniquely displayed triple-action inhibition, among which CDSO3, a sulfated caffeic acid-based LMWL, was most potent. The half-maximal anti-human neutrophil elastase (HNE) potency of CDSO3 was 0.43 μM. This high potency arose from lignin-like oligomerization, which was further potentiated by 6.6-fold due to sulfation. Mechanistically, this elastase inhibition was of mixed-type, time-dependent and more selective to positively charged elastases. The half-maximal anti-oxidative potency of CDSO3 was 3.52 μM, 4.8-fold potentiated from that of the monomer, caffeic acid (CA). In contrast, the half-maximal inhibitory potency to TNFα-induced inflammation was 5-10 μM, despite no activity with the monomer. More intriguingly, this anti-inflammatory activity was essentially identical with different stimuli, okadaic acid and hydrogen peroxide (H(2)O(2)), which implied that CDSO3 acts directly on inflammatory cascades within the cells. Overall, oligomerization and sulfation produced or significantly potentiated the activity, in comparison to the monomer. Thus, sulfated and unsulfated LMWLs are novel non-peptidic 2.8-4.1 kDa macromolecules that exhibit for the first time potent triple inhibitory activity against elastase, oxidation and inflammation, the three major pathogenic mechanisms known to cause emphysema.

Targeting TGFβ superfamily ligand accessory proteins as novel therapeutics for chronic lung disorders

Dysregulation of the transforming growth factor β (TGFβ) pathway has been implicated to underlie a number of disease indications including chronic lung disorders such as asthma, chronic obstructive pulmonary disease (COPD), interstitial pneumonias, and pulmonary arterial hypertension (PAH). Consequently, the pharmaceutical industry has devoted significant resources in the pursuit of TGFβ pathway inhibitors that target the cognate type I and II receptors and respective ligands. The progress of these approaches has been painfully slow, due in part to dose-limiting safety issues that result from the antagonism of a pathway that is responsible for regulating many fundamental biological processes including immune surveillance and cardiovascular responses. These disappointments have led many in the field to conclude that modulating the TGFβ pathway for chronic indications with a sufficient safety window using conventional approaches may be extremely difficult to achieve. Here we review the rationale and limitations of the use of TGFβ pathway inhibitors in chronic lung disorders and the possibility of targeting TGFβ superfamily ligand accessory proteins to allow rheostatic regulation of signaling to achieve efficacy while maintaining a sufficient therapeutic index.