A randomized clinical trial of alpha(1)-antitrypsin augmentation therapy

CT Chest Imaging Using Normalized Join-Count: Predicting Emphysema Progression in the CanCOLD Study

Background Pre-existing emphysema is recognized as an indicator of future worsening in patients with chronic obstructive pulmonary disease (COPD) when observed through CT imaging. However, it remains uncertain whether additional factors, such as the spatial compactness of CT emphysema, might also serve as predictors of disease progression. Purpose To evaluate the relationship between the compactness of CT emphysema voxels and emphysema progression. Materials and Methods This secondary analysis uses data from the prospective Canadian Cohort Obstructive Lung Disease (CanCOLD) study, examining CT images obtained in participants with and without COPD at baseline and a 3-year follow-up time point (November 2009 to November 2018). Measurements of forced expiratory volume in first second of expiration (FEV1) and diffusing capacity of lung for carbon monoxide (DLco) were collected. The normalized join-count (NJC) measurement from baseline CT images and lung density (LD) changes were analyzed. Emphysema progression was defined as an annualized LD change of less than half an SD below the mean of the participants without COPD with no smoking history. Multivariable linear and logistic regression models were used to assess the association between baseline CT NJC measurements and the annualized change in LD, FEV1, DLco, and emphysema progression versus nonprogression. Results A total of 524 participants (mean age, 66 years ± 10 [SD]; 293 male) (FEV1 percent predicted, 88% ± 19; FEV1/FVC, 67% ± 9; DLco percent predicted, 105% ± 25) were analyzed, 187 (36%) of whom had COPD. CT NJC was associated with the annualized change in LD (P < .001), FEV1 (P = .02), and DLco (P = .01). Additionally, CT NJC predicted emphysema progression versus nonprogression (odds ratio, 2.24; 95% CI: 1.37, 3.50; P < .001). Conclusion The spatial distribution, or "compactness," of CT emphysema voxels predicted emphysema progression in individuals with and without COPD. ClinicalTrials.gov Identifier: NCT00920348 © RSNA, 2024 Supplemental material is available for this article.

Antitrypsin deficiency: still more to learn about the lung after 60 years

The past 60 years have seen multiple publications related to lung disease in α1-antitrypsin deficiency largely reflecting the pathophysiology, biochemical effect and outcomes of augmentation therapy. However, the complexity of disease phenotype and the impact of the natural history presents problems of patient management, study design and hence interpretation of outcome. Although many national and some international registries exist, the lack of consistent in-depth assessment and importantly, the impact of augmentation therapy likely influences our perception of the true natural history. Development of new therapeutic strategies, and even assessment of the role and efficacy of augmentation, remain a challenge as powering such studies for conventional COPD outcomes is impractical due to relative rarity of the genetic condition and the presence of clinical phenotypic variation. The current review approaches these issues, discusses the nature and complexity of assessing patient variability, and provides guidance on further studies required to address them.

Assessing the efficacy of Alpha1-Proteinase inhibitor (human) augmentation therapy for Alpha1-Antitrypsin deficiency - Related emphysema: Challenges and opportunities

Clinical benefit of Alpha1-Proteinase Inhibitor (Human) (A1-PI) products for Alpha1-antitrypsin deficiency (AATD) is uncertain, based on a systematic review of observational studies and randomized controlled trials (RCTs) in AATD of Alpha1-Proteinase Inhibitor (Human) (A1-PI) products. At the recommended dose, A1-PI products raise its serum concentration but do not normalize levels. Observational studies suggest A1-PI might modestly slow progression of airflow limitation in patients with intermediate airflow obstruction, a finding not confirmed by three placebo-controlled RCTs of limited power, which showed non-significant rates of forced expiratory volume in 1 s (FEV1) change favoring placebo. These RCTs found trends favoring A1-PI in loss of high-resolution computerized tomographic (HRCT) lung density. While two meta-analyses of HRCT lung density change in RCTs achieved significance favoring A1-PI arms, clinical benefit remains uncertain. HRCT lung density measurements don't distinguish changes in measured density due to fluid shifts into and out of the lungs and changes in lung inflammation from those due to progressive loss of alveolar mass. A meta-analysis of RCTs found exacerbations significantly increased in A1-PI groups compared to placebo. No RCTs have shown favorable effects of A1-PI on mortality, FEV1, 6-min walking distance, quality of life, change in diffusion capacity of carbon monoxide (DLCO), or exacerbation frequency. A fourth RCT comparing two dose regimens of A1-PI is underway. RCTs have not provided evidence of clinical benefit in terms of how patients feel, function, or survive. Results have implications for the design of future clinical trials of A1-PI and potentially other products targeting AATD-associated emphysema.

[Alpha 1-antitrypsin deficiency]

Alpha 1‑antitrypsin (AAT) deficiency represents a complex genetic disorder and necessitates an interdisciplinary approach in the clinical practice. This article provides an overview of the epidemiology, genetics, symptoms, diagnostics and treatment of AAT deficiency. Knowledge and an in-depth understanding of AAT deficiency are indispensable to improve the early recognition of AAT, to optimize the quality of life of those affected and to enable targeted treatment interventions.

UK guideline on the transition and management of childhood liver diseases in adulthood

INTRODUCTION

Improved outcomes of liver disease in childhood and young adulthood have resulted in an increasing number of young adults (YA) entering adult liver services. The adult hepatologist therefore requires a working knowledge in diseases that arise almost exclusively in children and their complications in adulthood.

AIMS

To provide adult hepatologists with succinct guidelines on aspects of transitional care in YA relevant to key disease aetiologies encountered in clinical practice.

METHODS

A systematic literature search was undertaken using the Pubmed, Medline, Web of Knowledge and Cochrane database from 1980 to 2023. MeSH search terms relating to liver diseases ('cholestatic liver diseases', 'biliary atresia', 'metabolic', 'paediatric liver diseases', 'autoimmune liver diseases'), transition to adult care ('transition services', 'young adult services') and adolescent care were used. The quality of evidence and the grading of recommendations were appraised using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) system.

RESULTS

These guidelines deal with the transition of YA and address key aetiologies for the adult hepatologist under the following headings: (1) Models and provision of care; (2) screening and management of mental health disorders; (3) aetiologies; (4) timing and role of liver transplantation; and (5) sexual health and fertility.

CONCLUSIONS

These are the first nationally developed guidelines on the transition and management of childhood liver diseases in adulthood. They provide a framework upon which to base clinical care, which we envisage will lead to improved outcomes for YA with chronic liver disease.

Evaluation of body weight-based dosing, alternative dosing regimens, and treatment interruptions for α1-proteinase inhibitors and implications on biochemical efficacy in patients with α1-antitrypsin deficiency

INTRODUCTION

The recommended standard dose for α1-proteinase inhibitor (A1PI) augmentation therapy is 60 mg/kg once-weekly (QW) intravenous (IV) infusions that aim to maintain systemic A1PI levels >11 μM, the biochemical efficacy threshold, in patients with α1-antitrypsin deficiency (AATD). However, this standard dose may not be optimal for all patients. Body weight-based dosing, alternative dosing regimens, and treatment interruption periods were evaluated using population pharmacokinetic (PopPK) modeling and simulations.

METHODS

A nonlinear mixed-effects PopPK model with covariate effects was developed using data from 3 clinical studies investigating 60 mg/kg QW IV A1PI infusions in patients with AATD (n = 65) to evaluate A1PI pharmacokinetic (PK) characteristics. Model-based simulations were conducted for predefined body weight categories, alternative dosing regimens (60-180 mg/kg QW or once every 2 weeks [Q2W]), and treatment interruption periods ranging from 3 to 14 days.

RESULTS

A1PI PK characteristics were well described by a 2-compartment turnover model with zero-order input and linear elimination. Body weight was a statistically significant determinant of variability in central volume of distribution. Model-based simulations suggested that patients with a higher body weight may attain the 11 μM threshold quicker than patients with a lower body weight and that QW dosing was better at maintaining A1PI levels >11 μM, even when higher Q2W doses were administered. Missing a dose for as few as 3 days could result in A1PI levels <11 μM.

DISCUSSION

Findings suggest that doses higher than 60 mg/kg administered QW might be more clinically beneficial in some patients with AATD, and that body weight should be considered in dose optimization.

Augmentation Therapy for Severe Alpha-1 Antitrypsin Deficiency Improves Survival and Is Decoupled from Spirometric Decline-A Multinational Registry Analysis

Rationale: Intravenous plasma-purified alpha-1 antitrypsin (IV-AAT) has been used as therapy for alpha-1 antitrypsin deficiency (AATD) since 1987. Previous trials (RAPID and RAPID-OLE) demonstrated efficacy in preserving computed tomography of lung density but no effect on FEV1. This observational study evaluated 615 people with severe AATD from three countries with socialized health care (Ireland, Switzerland, and Austria), where access to standard medical care was equal but access to IV-AAT was not. Objectives: To assess the real-world longitudinal effects of IV-AAT. Methods: Pulmonary function and mortality data were utilized to perform longitudinal analyses on registry participants with severe AATD. Measurements and Main Results: IV-AAT confers a survival benefit in severe AATD (P < 0.001). We uncovered two distinct AATD phenotypes based on an initial respiratory diagnosis: lung index and non-lung index. Lung indexes demonstrated a more rapid FEV1 decline between the ages of 20 and 50 and subsequently entered a plateau phase of minimal decline from 50 onward. Consequentially, IV-AAT had no effect on FEV1 decline, except in patients with a Global Initiative for Chronic Obstructive Lung Disease (GOLD) stage 2 lung index. Conclusions: This real-world study demonstrates a survival advantage from IV-AAT. This improved survival is largely decoupled from FEV1 decline. The observation that patients with severe AATD fall into two major phenotypes has implications for clinical trial design where FEV1 is a primary endpoint. Recruits into trials are typically older lung indexes entering the plateau phase and, therefore, unlikely to show spirometric benefits. IV-AAT attenuates spirometric decline in lung indexes in GOLD stage 2, a spirometric group commonly outside current IV-AAT commencement recommendations.

Testing Patterns and Disparities for Alpha-1 Antitrypsin Deficiency

BACKGROUND

Alpha-1 antitrypsin deficiency is an under-recognized genetic cause of chronic lung and liver disease; it remains unclear what the testing frequency and disparities are for alpha-1 antitrypsin deficiency.

METHODS

This is a retrospective cohort study of people with newly diagnosed chronic obstructive pulmonary disease and liver disease identified at the University of Florida between January 1, 2012 and December 31, 2021. We performed incidence and prevalence analysis for alpha-1 antitrypsin (AAT) testing and point-biserial correlation analysis for tobacco use and AAT testing. We evaluated characteristics with AAT testing using adjusted multivariable logistic regression.

RESULTS

Among 75,810 subjects with newly diagnosed chronic obstructive pulmonary disease and liver disease between 2012 and 2021, 4248 (5.6%) were tested for AAT deficiency. All subjects had an AAT level performed, while 1654 (39%) had phenotype testing. Annual incidence of testing increased for subjects with newly diagnosed chronic obstructive pulmonary disease or liver disease from 2.8% and 5.4%, respectively, in 2012 to 4.1% and 11.3%, respectively, in 2021. Adjusted multivariable regression analysis showed factors favoring AAT testing were White race, and concomitant chronic obstructive pulmonary disease and liver disease. Increasing age, non-White race, current tobacco use, and being a male with chronic obstructive pulmonary disease had lower odds of AAT testing.

CONCLUSION

Although slowly improving, testing for AAT deficiency continues to have a low uptake in the clinical setting despite guidelines recommending broader testing. Individuals of White race and those with concomitant chronic obstructive pulmonary disease and liver disease are more likely to be tested, while older subjects, individuals of non-White race, current tobacco use, and men with chronic obstructive pulmonary disease are less favored to be tested.

Diagnosis and augmentation therapy for alpha-1 antitrypsin deficiency: current knowledge and future potential

The underdiagnosis of alpha-1 antitrypsin (AAT) deficiency (AATD) has been recognized for many years, yet little progress has been made in treatment of the disease. In this review, we summarize the AATD disease process as well as its diagnosis and treatment by AAT augmentation therapy. AATD is a rare autosomal disease that primarily affects the lungs and liver. AATD is associated with an increased susceptibility to developing pulmonary emphysema. The specific pharmacological treatment for AATD is intravenous administration of exogenous AAT. Augmentation therapy with AAT increases serum and pulmonary epithelial AAT levels, restores anti-elastase capacity, and decreases inflammatory mediators in the lung. Augmentation therapy reduces the loss of lung density over time, thus slowing progression of the disease. The effects of augmentation therapy on outcomes, such as frequency/duration of flare-ups, quality of life, lung function decline and mortality, are assessed. Wider testing for AATD, potentially through primary care physicians, could result in earlier treatment and better outcomes for individuals with AATD-induced lung respiratory disease.

Alpha-1 antitrypsin deficiency: current therapy and emerging targets

INTRODUCTION

Alpha1 antitrypsin deficiency (AATD), a common hereditary disorder affecting mainly lungs, liver and skin has been the focus of some of the most exciting therapeutic approaches in medicine in the past 5 years. In this review, we discuss the therapies presently available for the different manifestations of AATD and new therapies in the pipeline.

AREAS COVERED

We review therapeutic options for the individual lung, liver and skin manifestations of AATD along with approaches which aim to treat all three. Along with this renewed interest in treating AATD come challenges. How is AAT best delivered to the lung? What is the desired level of AAT in the circulation and lungs which therapeutics should aim to provide? Will treating the liver disease increase the potential for lung disease? Are there treatments to target the underlying genetic defect with the potential to prevent all aspects of AATDrelated disease?

EXPERT OPINION

With a relatively small population able to participate in clinical studies, increased awareness and diagnosis of AATD is urgently needed. Better, more sensitive clinical parameters will assist in the generation of acceptable and robust evidence of therapeutic effect for current and emerging treatments.

The effect of exacerbations on lung density in α1-antitrypsin deficiency

Background

Acute exacerbations of COPD (AECOPD) have unclear impacts on emphysema measurement using computed tomography (CT)-derived 15th percentile lung density (PD15). The aim of this study was to assess the influence of AECOPD on PD15 lung density in α₁-antitrypsin deficiency.

Methods

In a post hoc analysis of the RAPID (Randomised Trial of Augmentation Therapy in α₁-Proteinase Inhibitor Deficiency) trial, raw marginal residuals of PD15 (measured - predicted) were determined by fitting a regression line to individual patient CT data. These deviations from the expected slope were compared by age, sex, baseline forced expiratory volume in 1 s, diffusing capacity of the lungs for carbon monoxide % predicted and PD15, inhaled corticosteroid use and treatment group.

Results

Positive and negative residuals (reflecting higher or lower lung density than predicted from regression) were observed, which declined in magnitude over time following AECOPD events. Logistic regression confirmed a limited effect of patient characteristics on the absolute size of residuals, whereas AECOPD within 6 weeks of CT had a notable effect versus no AECOPD within 6 weeks (OR 5.707, 95% CI 3.375-9.652; p<0.0001).

Conclusion

AECOPD result in higher or lower CT lung density estimates; the effect is greatest in the 2 weeks immediately after an AECOPD and persists for <6 weeks. Patient characteristics were less relevant than AECOPD within 6 weeks, supporting the reliability of PD15 as a measure of lung density. An exacerbation-free period prior to CT scan is advisable to reduce signal-to-noise ratio in future clinical trials.

Resolution of hepatic fibrosis after ZFN-mediated gene editing in the PiZ mouse model of human α1-antitrypsin deficiency

BACKGROUND

α1-antitrypsin deficiency is most commonly caused by a mutation in exon-7 of SERPINA1 (SA1-ATZ), resulting in hepatocellular accumulation of a misfolded variant (ATZ). Human SA1-ATZ-transgenic (PiZ) mice exhibit hepatocellular ATZ accumulation and liver fibrosis. We hypothesized that disrupting the SA1-ATZ transgene in PiZ mice by in vivo genome editing would confer a proliferative advantage to the genome-edited hepatocytes, enabling them to repopulate the liver.

METHODS

To create a targeted DNA break in exon-7 of the SA1-ATZ transgene, we generated 2 recombinant adeno-associated viruses (rAAV) expressing a zinc-finger nuclease pair (rAAV-ZFN), and another rAAV for gene correction by targeted insertion (rAAV-TI). PiZ mice were injected i.v. with rAAV-TI alone or the rAAV-ZFNs at a low (7.5×1010vg/mouse, LD) or a high dose (1.5×1011vg/mouse, HD), with or without rAAV-TI. Two weeks and 6 months after treatment, livers were harvested for molecular, histological, and biochemical analyses.

RESULTS

Two weeks after treatment, deep sequencing of the hepatic SA1-ATZ transgene pool showed 6%±3% or 15%±4% nonhomologous end joining in mice receiving LD or HD rAAV-ZFN, respectively, which increased to 36%±12% and 36%±12%, respectively, 6 months after treatment. Two weeks postinjection of rAAV-TI with LD or HD of rAAV-ZFN, repair by targeted insertion occurred in 0.10%±0.09% and 0.25%±0.14% of SA1-ATZ transgenes, respectively, which increased to 5.2%±5.0% and 33%±13%, respectively, 6 months after treatment. Six months after rAAV-ZFN administration, there was a marked clearance of ATZ globules from hepatocytes, and resolution of liver fibrosis, along with reduction of hepatic TAZ/WWTR1, hedgehog ligands, Gli2, a TIMP, and collagen content.

CONCLUSIONS

ZFN-mediated SA1-ATZ transgene disruption provides a proliferative advantage to ATZ-depleted hepatocytes, enabling them to repopulate the liver and reverse hepatic fibrosis.

The impact of diagnostic delay on survival in alpha-1-antitrypsin deficiency: results from the Austrian Alpha-1 Lung Registry

BACKGROUND

Alpha-1-antitrypsin (AAT) deficiency (AATD) is a genetic disorder that can manifest as lung disease. A delay between onset of symptoms and diagnosis of AATD is common and associated with worse clinical status and more advanced disease stage but the influence on survival is unclear.

OBJECTIVE

We aimed to investigate the impact of diagnostic delay on overall survival (OS) and transplant-free survival (TS) in AATD patients.

METHODS

We analysed 268 AATD patients from the prospective multi-centre Austrian Alpha-1 Lung (AAL) Registry, employing descriptive statistics, Chi-square-test as well as univariable (Kaplan-Meier plots, log-rank test) and multivariable survival analysis (Cox regression).

RESULTS

The predominant phenotype was Pi*ZZ (82.1%). At diagnosis, 90.2% had an AAT level below 0.6 g/L. At inclusion, 28.2% had never smoked, 68.0% had quit smoking and 3.8% continued to smoke. Lung disease was diagnosed in 98.5%, thereof most patients were diagnosed with emphysema (63.8%) and/or chronic obstructive pulmonary disease (44.0%). Median diagnostic delay was 5.3 years (inter-quartile range [IQR] 2.2-11.5 years). In multivariable analysis (n = 229), a longer diagnostic delay was significantly associated with worse OS (hazard ratio [HR] 1.61; 95% CI 1.09-2.38; p = 0.016) and TS (HR 1.43; 95% CI 1.08-1.89; p = 0.011), independent from age, smoking status, body mass index (BMI), forced expiratory volume in one second (FEV₁) and long-term oxygen treatment. Furthermore, BMI, age and active smoking were significantly associated with worse OS as well as BMI, active smoking and FEV₁ were with worse TS.

CONCLUSIONS

A delayed diagnosis was associated with significantly worse OS and TS. Screening should be improved and efforts to ensure early AATD diagnosis should be intensified.

Long-term safety of Prolastin®-C, an alpha1-proteinase inhibitor, in Japanese patients with alpha1-antitrypsin deficiency

BACKGROUND

Safety and pharmacokinetics (PK) of alpha₁-proteinase inhibitor, modified process (Alpha-1 MP), was evaluated in a clinical trial of Japanese patients with alpha₁-antitrypsin deficiency (AATD). The present study aimed to evaluate the long-term safety of weekly intravenous infusions of 60 mg/kg Alpha-1 MP in Japanese patients with AATD.

METHODS

This was a multi-center, open-label extension (OLE) study that enrolled adult patients with AATD, who had completed the preceding safety and PK clinical trial. Patients were administered with Alpha-1 MP (60 mg/kg) weekly, for 52 weeks, and this could be renewed annually. Alpha1-MP trough levels (C_min) were evaluated, and safety endpoints include: treatment-emergent adverse events (TEAEs), serious adverse events (SAEs), TEAEs potentially related to Alpha-1 MP, chronic obstructive pulmonary disease (COPD) exacerbations, laboratory parameters, vital signs, and pulmonary function tests (forced expiration volume in 1 s [FEV₁] and forced vital capacity [FVC]).

RESULTS

Four patients underwent Alpha-1 MP intravenous infusions at a mean (SD) of 210.8 (9.54) for 213 weeks (four years), with a C_min of 55.73 (4.99) mg/dL. A total of fifty-four TEAEs were reported in four patients, in which most of them were mild (n = 52, 96.3%). Two patients had five SAEs, and all were unrelated to treatment. Three mild TEAEs were potentially related to treatment with Alpha-1 MP. No clinically significant findings in laboratory parameters, COPD exacerbations, or vital signs were observed. There were no identifiable differences in FEV₁ and FVC throughout the study period.

CONCLUSIONS

Long-term weekly intravenous infusions of 60 mg/kg Alpha-1 MP are generally safe and well-tolerated in Japanese patients with AATD.

CLINICALTRIALS

GOV: NCT02870348; JAPIC CTI: JapicCTI-163194.

Quantitative CT Lung Imaging and Machine Learning Improves Prediction of Emergency Room Visits and Hospitalizations in COPD

RATIONALE

Predicting increased risk of future healthcare utilization in chronic obstructive pulmonary disease (COPD) patients is an important goal for improving patient management.

OBJECTIVE

Our objective was to determine the importance of computed tomography (CT) lung imaging measurements relative to other demographic and clinical measurements for predicting future health services use with machine learning in COPD.

MATERIALS AND METHODS

In this retrospective study, lung function measurements and chest CT images were acquired from Canadian Cohort of Obstructive Lung Disease study participants from 2010 to 2017 (https://clinicaltrials.gov, NCT00920348). Up to two follow-up visits (1.5- and 3-year follow-up) were performed and participants were asked for details related to healthcare utilization. Healthcare utilization was defined as any COPD hospitalization or emergency room visit due to respiratory problems in the 12 months prior to the follow-up visits. CT analysis was performed (VIDA Diagnostics Inc.); a total of 108 CT quantitative emphysema, airway and vascular measurements were investigated. A hybrid feature selection method with support vector machine classifier was used to predict healthcare utilization. Performance was determined using accuracy, F1-measure and area under the receiver operating characteristic curve (AUC) and Matthews's correlation coefficient (MC).

RESULTS

Of the 527 COPD participants evaluated, 179 (35%) used healthcare services at follow-up. There were no significant differences between the participants with or without healthcare utilization at follow-up for age (p = 0.50), sex (p = 0.44), BMI (p = 0.05) or pack-years (p = 0.76). The accuracy for predicting subsequent healthcare utilization was 80% ± 3% (F1-measure = 74%, AUC = 0.80, MC = 0.6) when all measurements were considered, 76% ± 6% (F1-measure = 72%, AUC = 0.77, MC = 0.55) for CT measurements alone and 65% ± 5% (F1-measure = 60%, AUC = 0.67, MC = 0.34) for demographic and lung function measurements alone.

CONCLUSION

The combination of CT lung imaging and conventional measurements leads to greater prediction accuracy of subsequent health services use than conventional measurements alone, and may provide needed prognostic information for patients suffering from COPD.

Alpha-1 Asthma Overlap Syndrome: a Clinical Overview

PURPOSE OF REVIEW

Alpha-1 antitrypsin deficiency (AATD) is one of the most common genetic diseases that is associated with severe complications and yet remains underdiagnosed. The pulmonary symptoms of both AATD and asthma include cough, excessive sputum production, dyspnea, and wheezing. These symptoms overlap significantly leading to difficulty distinguishing between these two conditions and suspicion that there may be an overlap syndrome. We aim to discuss the pathophysiology, clinical manifestations, and treatment of both alpha-1 antitrypsin and asthma and how they may overlap.

RECENT FINDINGS

Recent literature suggests that there is an association between asthma and AATD. This association has been hypothesized to be secondary to an imbalance of elastase and anti-elastase leading to a pro-inflammatory state in patients with AATD. This review serves to overview the pathophysiology, clinical manifestations, and treatment of alpha-1 antitrypsin, asthma, and the increasingly recognized intersection of the two, AATD-asthma overlap syndrome.

Differentiating COPD and Asthma using Quantitative CT Imaging and Machine Learning

There are similarities and differences between chronic obstructive pulmonary disease (COPD) and asthma patients in terms of computed tomography (CT) disease-related features. Our objective was to determine the optimal subset of CT imaging features for differentiating COPD and asthma using machine learning.COPD and asthma patients were recruited from Heidelberg University Hospital. CT was acquired and 93 features were extracted (VIDA Diagnostics): percentage of low-attenuating-areas below -950HU (LAA₉₅₀), LAA₉₅₀ hole count, estimated airway-wall-thickness for a 10 mm internal perimeter airway (Pi10), total-airway-count (TAC), as well as inner/outer perimeter/areas and wall thickness for each of five segmental airways, and the average of those five airways. Hybrid feature selection was used to select the optimum number of features, and support vector machine was used to classify COPD and asthma.Ninety-five participants were included (n=48 COPD; n=47 asthma); there were no differences between COPD and asthma for age (p=0.25) or FEV₁ (p=0.31). In a model including all CT features, the accuracy and F1-score was 80% and 81%, respectively. The top features were: LAA_950, LAA₉₅₀ hole count, average outer and inner airway perimeter, outer and inner airway area RB1, and TAC. In the model with only airway features, the accuracy and F1-score were 66% and 68%, respectively. The top features were: inner area RB1, wall thickness RB1, outer area LB1, TAC LB10, average outer/inner perimeter, Pi10, and TAC.In conclusions, COPD and asthma can be differentiated using machine learning with moderate-high accuracy by a subset of only 7 CT features.

The emerging role of proteases in α1-antitrypsin deficiency and beyond

α1-Antitrypsin deficiency (AATD) has been historically under-recognised and under-diagnosed; recently it has begun to receive greater interest in terms of attempts at deeper elucidation of pathology and treatment options. However, the concept of disease phenotypes within AATD (emphysema, chronic bronchitis, bronchiectasis or a combination of phenotypes) has not been proposed or studied. Of the three neutrophil serine proteases, neutrophil elastase was historically believed to be the sole contributor to disease pathology in AATD. Recently, Proteinase-3 has been increasingly studied as an equal, if not greater, contributor to the disease process. Cathepsin G, however, has not been extensively evaluated in this area. Matrix metalloproteinases have also been mentioned in the pathogenesis of AATD but have not been widely explored. This article considers the available evidence for differential protease activity in patients with AATD, including the contribution to distinct phenotypes of the disease. Owing to limited literature in this area, extrapolations from studies of other chronic lung diseases with similar phenotypes, including COPD and bronchiectasis, have been made. We consider a new framework of understanding defined by protease-driven endotypes of disease which may lead to new opportunities for precision medicine.

Spatial Dependence of CT Emphysema in Chronic Obstructive Pulmonary Disease Quantified by Using Join-Count Statistics

Background Existing CT emphysema measurements quantify the extent or clustering of emphysema voxels in chronic obstructive pulmonary disease (COPD); however, these measurements do not quantify how those voxels are clustered. Purpose To develop a CT measurement to quantify the "compactness" of emphysema voxels, called the normalized join count (NJC), and to determine whether the NJC measurement differentiates COPD disease severity and correlates with lung function and visual emphysema scores. Materials and Methods In this secondary analysis of a prospective study, lung function and CT images were obtained from the Canadian Cohort Obstructive Lung Disease study visit 1 from 2009 to 2013. Participants were categorized as never-smokers, at risk, mild COPD, or moderate-severe COPD. Diffusion capacity for carbon monoxide/alveolar volume was measured. CT emphysema was scored visually by radiologists. CT measurements included the percentage low-attenuation area with attenuation less than -950 HU (%LAA_-950insp), low-attenuation cluster (LAC), and lowest 15th percentile point of the CT lung density histogram. NJC was developed to measure compactness of CT emphysema voxels. An analysis of variance determined differences between groups. Multivariable ridge regression determined association between CT measurements with lung function and radiologist scores. Results A total of 1294 participants (750 men; mean age, 67 years ± 10) were analyzed (277 never-smokers, 306 at risk, 427 mild COPD, and 284 moderate-severe COPD). NJC, %LAA_-950insp, and LAC measurements were higher in moderate-severe COPD than in never-smokers and at-risk participants (P < .05 for all comparisons), but only NJC was different between mild and ;moderate-severe COPD (mean, 1.98% ± 3.61 vs 1.44% ± 2.14; P < .05). In multivariable regression analysis, among all CT measurements NJC had the greatest relative contribution to diffusion capacity for carbon monoxide/alveolar volume (P = .002) and visual emphysema score (P < .001). Conclusion The relationship of normalized join count with severity of chronic obstructive pulmonary disease may indicate that the assessment of this disease is dependent on the number of low attenuating voxels or the size of clusters and the spatial arrangement of such voxels. © RSNA, 2021 Online supplemental material is available for this article. See also the editorial by Grenier in this issue.

Imaging in alpha-1 antitrypsin deficiency: a window into the disease

Imaging modalities such as plain chest radiograph and computed tomography (CT) are important tools in the assessment of patients with chronic obstructive pulmonary disease (COPD) of any etiology. These methods facilitate differential diagnoses and the assessment of individual lung pathologies, such as the presence of emphysema, bullae, or fibrosis. However, as emphysema is the core pathological consequence in the lungs of patients with alpha-1 antitrypsin deficiency (AATD), and because AATD is associated with the development of other lung pathologies such as bronchiectasis, there is a greater need for patients with AATD than those with non-AATD-related COPD to undergo more detailed assessment using CT. In the field of AATD, CT provides essential information regarding the presence, distribution, and morphology of emphysema. In addition, it offers the option to quantify the extent of emphysema. These data have implications for treatment decisions such as initiation of alpha-1 antitrypsin (AAT) therapy, or suitability for surgical or endoscopic interventions for reducing lung volume. Furthermore, CT has provided vital insight regarding the natural history of emphysema progression in AATD, and CT densitometry has underpinned research into the efficacy of AAT therapy. Moving forward, hyperpolarized xenon gas (129Xe) lung magnetic resonance imaging (MRI) is emerging as a promising complement to CT by adding comprehensive measures of regional lung function. It also avoids the main disadvantage of CT: the associated radiation. This chapter provides an overview of technological aspects of imaging in AATD, as well as its role in the management of patients and clinical research. In addition, perspectives on the future potential role of lung MRI in AATD are outlined.

Management of lung disease in alpha-1 antitrypsin deficiency: what we do and what we do not know

Management of lung disease in patients with alpha-1 antitrypsin deficiency (AATD) includes both non-pharmacological and pharmacological approaches. Lifestyle changes with avoidance of environmental pollutants, including tobacco smoke, improving exercise levels and nutritional status, all encompassed under a disease management program, are crucial pillars of AATD management. Non-pharmacological therapies follow conventional treatment guidelines for chronic obstructive pulmonary disease. Specific pharmacological treatment consists of administering exogenous alpha-1 antitrypsin (AAT) protein intravenously (augmentation therapy). This intervention raises AAT levels in serum and lung epithelial lining fluid, increases anti-elastase capacity, and decreases several inflammatory mediators in the lung. Radiologically, augmentation therapy reduces lung density loss over time, thus delaying disease progression. The effect of augmentation therapy on other lung-related outcomes, such as exacerbation frequency/length, quality of life, lung function decline, and mortality, are less clear and questions regarding dose optimization or route of administration are still debatable. This review discusses the rationale and available evidence for these interventions in AATD.

Neutrophil Elastase and Chronic Lung Disease

Neutrophil elastase (NE) is a major inflammatory protease released by neutrophils and is present in the airways of patients with cystic fibrosis (CF), chronic obstructive pulmonary disease, non-CF bronchiectasis, and bronchopulmonary dysplasia. Although NE facilitates leukocyte transmigration to the site of infection and is required for clearance of Gram-negative bacteria, it also activates inflammation when released into the airway milieu in chronic inflammatory airway diseases. NE exposure induces airway remodeling with increased mucin expression and secretion and impaired ciliary motility. NE interrupts epithelial repair by promoting cellular apoptosis and senescence and it activates inflammation directly by increasing cytokine expression and release, and indirectly by triggering extracellular trap release and exosome release, which magnify protease activity and inflammation in the airway. NE inhibits innate immune function by digesting opsonins and opsonin receptors, degrading innate immune proteins such as lactoferrin, and inhibiting macrophage phagocytosis. Importantly, NE-directed therapies have not yet been effective in preventing the pathologic sequelae of NE exposure, but new therapies are being developed that offer both direct antiprotease activity and multifunctional anti-inflammatory properties.

Long-term effect of α1-antitrypsin augmentation therapy on the decline of FEV1 in deficient patients: an analysis of the AIR database

BACKGROUND

Patients with ZZ (Glu342Lys) α-1-antitrypsin deficiency (ZZ-AATD) who received augmentation therapy with α-1-antitrypsin (AAT) in randomised controlled trials over 2-3 years failed to show a significant reduction of the annual decline of forced expiratory volume in 1 s (FEV1).

METHODS

To compare the trajectory of FEV1 change during 4 or more years in ZZ-AATD patients with emphysema receiving or not receiving intravenous augmentation therapy, a retrospective analysis of FEV1 values entered in the Alpha-1 International Registry (AIR) of ZZ-AATD patients from five different European countries (Germany, UK, Spain, Italy and the Netherlands) was performed. The post-bronchodilator FEV1 % predicted values for baseline and follow-up over time from patients were analysed using linear mixed effects models.

RESULTS

Data of 374 patients were analysed: 246 untreated and 128 treated with intravenous AAT augmentation therapy. The mean±sd follow-up duration of the untreated group was 8.60±3.34 years and 8.59±2.62 years for the treated group. The mixed effects model analysis showed a mean FEV1 decline of -0.931% predicted per year (95% CI -1.144 to -0.718) in the untreated group and a decline of -1.016% predicted per year (95% CI -1.319 to -0.7145) in the treated group. The likelihood ratio test showed no difference between the two groups (p=0.71).

CONCLUSION

In our study population, we could not detect a significant difference in the annual decline of FEV1 by AAT augmentation treatment over a mean period of 8.6 years. Other approaches are needed to validate any benefit of augmentation therapy.

There is No Fast Track to Identify Fast Decliners in Alpha-1 Antitrypsin Deficiency by Spirometry: A Longitudinal Study of Repeated Measurements

Background

It is known that lung function decline in Alpha-1 Antitrypsin Deficiency (AATD) varies. Those with a rapid decline are at highest risk of poorer outcomes but may benefit most from targeted treatments including augmentation therapy. Current evidence suggests rapid decliners can be identified after 3 years of serial follow-up. It would be advantageous to identify these patients over a shorter time period, especially in mild disease.

Methods

Post-bronchodilator spirometry was performed every 6 months for a total of 18 months (4 measurements) by PiZZ AATD patients (ex- or never-smokers) either without spirometric COPD or with mild COPD. Where possible, retrospective spirometry data were included. Decline was assessed using 2 (baseline and 6 month) or four measurements (including baseline, 6, 12 and 18 months) and compared to retrospective decline rates using annual measurements over 3 years.

Results

Seventy-two PiZZ AATD patients were included, with 27 having at least three years of retrospective, annual spirometry. 18-month progression obtained by linear regression showed variable degrees of change with 29 showing no decline, 8 showing slow decline and 35 showing rapid decline. Bland-Altman plots showed that there was no overall agreement between predicted rate of decline using data obtained over 6 months and that obtained over 18 months. Furthermore, there was no agreement between rate of decline from either 6 or 18 months’ data when compared to data collected over 3 years. The positive predictive value for rapid decline with 18 months of data compared to 3 years was only 50.0%.

Conclusion

This study suggests serial lung function over 18 months cannot identify AATD patients who have rapidly declining lung function. There is an urgent need for different biomarkers to help identify these patients at the earliest opportunity.

Obstacles to Early Diagnosis and Treatment of Alpha-1 Antitrypsin Deficiency: Current Perspectives

This review summarizes the current research and outlooks regarding the obstacles to diagnosing and treating early alpha-1-antitrypsin deficiency (AATD). It draws on prior systematic reviews and expert surveys to discover precisely what difficulties exist in early diagnosis and treatment of AATD and elucidate potential solutions to ease these difficulties. The perceived rarity of AATD may translate to a condition poorly understood by primary care physicians, and even many respiratory physicians, which results in opportunities for diagnosis being missed, especially in mild or asymptomatic patients. There are diagnostic techniques involving biomarkers and home testing methods which could improve the rate of early diagnosis. With respect to treatment, AATD involves treating two separate pathologies, lung disease and liver disease. The only specific AATD treatment, augmentation therapy, has proven ability in treating lung disease but not liver disease. Alpha-1-antitrypsin (AAT) synthesized in the liver can form damaging polymers that also result in reduced circulating AAT levels and, whilst liver transplantation is used to effectively treat AATD, it is inappropriate in early disease. Novel therapeutic areas such as gene editing and increasing autophagy are therefore being researched as future treatments. Ultimately, diagnosis and treatment are intrinsically linked in AATD, with earlier diagnosis leading to better treatment options and thus better patient outcomes.

Medical costs of Alpha-1 antitrypsin deficiency-associated COPD in the United States

Background

There are limited data on economic aspects of the genetic variant of chronic obstructive pulmonary disease (COPD) in the context of the more prevalent form of COPD. The objective of this study was to isolate the healthcare resource utilization and economic burden attributable to the presence of a genetic factor among COPD patients with and without Alpha-1 Antitrypsin Deficiency (AATD), twelve months before and after their initial COPD diagnosis.

Methods

Retrospective analysis of OptumLabs® Data Warehouse claims (OLDW; 2000–2017). The OLDW is a comprehensive, longitudinal real-world data asset with de-identified lives across claims and clinical information. AATD-associated COPD cases were matched with up to 10 unique non-AATD-associated COPD controls. Healthcare resource use and costs were assigned into the following categories: office (OV), outpatient (OP), and emergency room visits (ER), inpatients stays (IP), prescription drugs (RX), and other services (OTH). A generalized linear model was used to estimate total pre- and post-index (initial COPD diagnosis) costs from a third-party payer’s perspective (2018 USD) controlling for confounders. Healthcare resource utilization was estimated using a negative binomial regression.

Results

The study population consisted of 8881 patients (953 cases matched with 7928 controls). The AATD-associated COPD cohort had higher expenditures and use of office visits (OV) and other (OTH) services, as well as OV, outpatient (OP), emergency room (ER), and prescription drugs (RX) before and after the index date, respectively. Adjusted total all-healthcare cost ratios for AATD-associated COPD patients as compared to controls were 2.04 [95% CI: 1.60–2.59] and 1.98 [95% CI: 1.55–2.52] while the incremental cost difference totaled $6861 [95% CI: $3025 - $10,698] and $5772 [95% CI: $1940 - $9604] per patient before and after the index date, respectively.

Conclusions

Twelve months before and after their initial COPD diagnosis, patients with AATD incur higher healthcare utilization costs that are double the cost of similar COPD patients without AATD. This study also suggests that increased costs of AATD-associated COPD are not solely attributable to augmentation therapy use. Future studies should further explore the relationship between augmentation therapy, healthcare resource use, and other AATD-associated COPD expenditures.

Implications of a Change of Paradigm in Alpha1 Antitrypsin Deficiency Augmentation Therapy: From Biochemical to Clinical Efficacy

Ever since the first studies, restoring proteinase imbalance in the lung has traditionally been considered as the main goal of alpha1 antitrypsin (AAT) replacement therapy. This strategy was therefore based on ensuring biochemical efficacy, identifying a protection threshold, and evaluating different dosage regimens. Subsequently, the publication of the results of the main clinical trials showing a decrease in the progression of pulmonary emphysema has led to a debate over a possible change in the main objective of treatment, from biochemical efficacy to clinical efficacy in terms of lung densitometry deterioration prevention. This new paradigm has produced a series controversies and unanswered questions which face clinicians managing AAT deficiency. In this review, the concepts that led to the approval of AAT replacement therapy are reviewed and discussed under a new prism of achieving clinical efficacy, with the reduction of lung deterioration as the main objective. Here, we propose the use of current knowledge and clinical experience to face existing challenges in different clinical scenarios, in order to help clinicians in decision-making, increase interest in the disease, and stimulate research in this field.

Inter- and intra-software reproducibility of computed tomography lung density measurements

PURPOSE

Multiple commercial, open-source, and academic software tools exist for objective quantification of lung density in computed tomography (CT) images. The purpose of this study was to evaluate the intersoftware reproducibility of CT lung density measurements.

METHODS

Computed tomography images from 50 participants from the COPDGene^TM cohort study were randomly selected for analysis; n = 10 participants across each global initiative for chronic obstructive lung disease (GOLD) grade (GOLD 0-IV). Academic-based groups (n = 4) and commercial vendors (n = 4) participated anonymously to generate CT lung density measurements using their software tools. Computed tomography total lung volume (TLV), percentage of the low attenuation areas in the lung with Hounsfield unit (HU) values below -950HU (LAA₉₅₀ ), and the HU value corresponding to the 15th percentile on the parenchymal density histogram (Perc15) were included in the analysis. The intersoftware bias and reproducibility coefficient (RDC) was generated with and without quality assurance (QA) for manual correction of the lung segmentation; intrasoftware bias and RDC was also generated by repeated measurements on the same images.

RESULTS

Intersoftware mean bias was within ±0.22 mL, ±0.46%, and ±0.97 HU for TLV, LAA₉₅₀ and Perc15, respectively. The RDC was 0.35 L, 1.2% and 1.8 HU for TLV, LAA₉₅₀ and Perc15, respectively. Intersoftware RDC remained unchanged following QA: 0.35 L, 1.2% and 1.8 HU for TLV, LAA₉₅₀ and Perc15, respectively. All software investigated had an intrasoftware RDC of 0. The RDC was comparable for TLV, LAA₉₅₀ and Perc15 measurements, respectively, for academic-based groups/commercial vendor-based software tools: 0.39 L/0.32 L, 1.2%/1.2%, and 1.7 HU/1.6 HU. Multivariable regression analysis showed that academic-based software tools had greater within-subject standard deviation of TLV than commercial vendors, but no significant differences between academic and commercial groups were found for LAA₉₅₀ or Perc15 measurements.

CONCLUSIONS

Computed tomography total lung volume and lung density measurement bias and reproducibility was reported across eight different software tools. Bias was negligible across vendors, reproducibility was comparable for software tools generated by academic-based groups and commercial vendors, and segmentation QA had negligible impact on measurement variability between software tools. In summary, results from this study report the amount of additional measurement variability that should be accounted for when using different software tools to measure lung density longitudinally with well-standardized image acquisition protocols. However, intrasoftware reproducibility was deterministic for all cases so use of the same software tool to reduce variability for serial studies is highly recommended.

Diagnosis and treatment of lung disease associated with alpha one-antitrypsin deficiency: A position statement from the Thoracic Society of Australia and New Zealand

AATD is a common inherited disorder associated with an increased risk of developing pulmonary emphysema and liver disease. Many people with AATD-associated pulmonary emphysema remain undiagnosed and therefore without access to care and counselling specific to the disease. AAT augmentation therapy is available and consists of i.v. infusions of exogenous AAT protein harvested from pooled blood products. Its clinical efficacy has been the subject of some debate and the use of AAT augmentation therapy was recently permitted by regulators in Australia and New Zealand, although treatment is not presently subsidized by the government in either country. The purpose of this position statement is to review the evidence for diagnosis and treatment of AATD-related lung disease with reference to the Australian and New Zealand population. The clinical efficacy and adverse events of AAT augmentation therapy were evaluated by a systematic review, and the GRADE process was employed to move from evidence to recommendation. Other sections address the wide range of issues to be considered in the care of the individual with AATD-related lung disease: when and how to test for AATD, changing diagnostic techniques, monitoring of progression, disease in heterozygous AATD and pharmacological and non-pharmacological therapy including surgical options for severe disease. Consideration is also given to broader issues in AATD that respiratory healthcare staff may encounter: genetic counselling, patient support groups, monitoring for liver disease and the need to establish national registries for people with AATD in Australia and New Zealand.

The Emerging Role of Radiomics in COPD and Lung Cancer

Medical imaging plays a key role in evaluating and monitoring lung diseases such as chronic obstructive pulmonary disease (COPD) and lung cancer. The application of artificial intelligence in medical imaging has transformed medical images into mineable data, by extracting and correlating quantitative imaging features with patients' outcomes and tumor phenotype - a process termed radiomics. While this process has already been widely researched in lung oncology, the evaluation of COPD in this fashion remains in its infancy. Here we outline the main applications of radiomics in lung cancer and briefly review the workflow from image acquisition to the evaluation of model performance. Finally, we discuss the current assessments of COPD and the potential application of radiomics in COPD.

Alpha-1 Antitrypsin Deficiency: Have We Got the Right Proteinase?

Alpha-1 antitrypsin deficiency (AATD) has traditionally been associated with the development of early onset panlobular emphysema thought to reflect the direct interstitial damage caused by neutrophil elastase. Since this enzyme is highly sensitive to irreversible inhibition by alpha-1 antitrypsin (AAT), the logic of intravenous augmentation therapy has remained unquestioned and efficacy is supported by both observational studies and formal clinical trials. However, evidence suggests that although AAT augmentation modulates the progression of emphysema, it only slows it down. This raises the issue of whether our long-held beliefs of the cause of the susceptibility to develop emphysema in deficient individuals are correct. There are several aspects of our understanding of the disease that might benefit from a radical departure from traditional thought. This review addresses these concepts and alternative pathways that may be central to progression of emphysema.

Experimental and investigational drugs for the treatment of alpha-1 antitrypsin deficiency

Introduction: Alpha-1 antitrypsin deficiency (AATD) is most often associated with chronic lung disease, early onset emphysema, and liver disease. The standard of care in lung disease due to AATD is alpha-1 antitrypsin augmentation but there are several new and emerging treatment options under investigation for both lung and liver manifestations. Areas covered: We review therapeutic approaches to lung and liver disease in alpha-1 antitrypsin deficiency (AATD) and the agents in clinical development according to their mode of action. The focus is on products in clinical trials, but data from pre-clinical studies are described where relevant, particularly where progression to trials appears likely. Expert opinion: Clinical trials directed at lung and liver disease separately are now taking place. Multimodality treatment may be the future, but this could be limited by treatment costs. The next 5-10 years may reveal new guidance on when to use therapeutics for slowing disease progression with personalized treatment regimes coming to the forefront.

Managing the Alpha-1 patient in the ICU: Adapting broad critical care strategies in AATD

Alpha-1 Antitrypsin Deficiency (AATD) is a progressive pulmonary disease under-recognized or misdiagnosed by clinicians. Patients with AATD can develop a variety of organ-specific complications and as a result, often require hospitalization and treatment within critical care and ICU settings. Due to the complexity of AATD there are minimal guidelines in place to address the specific and highly variable needs of these patients in the critical care setting. This review presents clinical considerations with respect to the management of patients with AATD and provides treatment recommendations for these patients in the critical care setting. In addition, we have outlined certain aspects of the care of this patient population that may be of interest to critical care practitioners. With greater disease awareness and earlier diagnosis the onset of symptoms can be delayed, which will ultimately reduce the frequency of deleterious health consequences.

Portuguese consensus document for the management of alpha-1-antitrypsin deficiency

Alpha-1-antitrypsin deficiency (AATD) is a genetic autosomal codominant disorder caused by mutations in SERPINA1 gene. It is one of the most prevalent genetic disorders, although it remains underdiagnosed. Whereas at international level there are several areas of consensus on this disorder, in Portugal, inter-hospital heterogeneity in clinical practice and resources available have been adding difficulties in reaching a diagnosis and in making therapeutic decisions in this group of patients. This raised a need to draft a document expressing a national consensus for AATD. To this end, a group of experts in this field was created within the Portuguese Pulmonology Society - Study group on AATD, in order to elaborate the current manuscript. The authors reviewed the existing literature and provide here general guidance and extensive recommendations for the diagnosis and management of AATD that can be adopted by Portuguese clinicians from different areas of Medicine. This article is part of a supplement entitled "Portuguese consensus document for the management of alpha-1-antitrypsin deficiency" which is sponsored by Sociedade Portuguesa de Pneumologia.

Pharmacogenomics of chronic obstructive pulmonary disease

INTRODUCTION

Chronic obstructive pulmonary disease (COPD) is a heterogeneous condition, which presents the opportunity for precision therapy based on genetics or other biomarkers. Areas covered: Alpha-1 antitrypsin deficiency, a genetic form of emphysema, provides an example of this precision approach to diagnosis and therapy. To date, research in COPD pharmacogenomics has been limited by small sample sizes, lack of accessible target tissue, failure to consider COPD subtypes, and different outcomes relevant for various medications. There have been several published genome-wide association studies and other omics studies in COPD pharmacogenomics; however, clinical implementation remains far away. There is a growing evidence base for precision prescription of inhaled corticosteroids in COPD, based on clinical phenotypes and blood biomarkers, but not yet based on pharmacogenomics. Expert opinion: At this time, there is insufficient evidence for clinical implementation of COPD pharmacogenomics. Additional genome-wide studies will be required to discover predictors of drug response and to identify genomic biomarkers of COPD subtypes, which could be targeted with subtype-directed therapies.

Current Advances in COPD Imaging

OBJECTIVE

To review the recent advances in available technologies for imaging COPD and present the novel optical coherence tomography (OCT) airway imaging technology.

MATERIALS AND METHODS

This is an unstructured review of published evidence of available pulmonary imaging technologies along with a demonstration of state-of-the-art OCT imaging technology of in vivo human and animal airways.

RESULTS

Advanced imaging techniques such as Magnetic Resonance (MR) imaging using hyperoloarized noble gases, micro-Computed Tomography (micro-CT), and OCT aim to further our understanding of COPD. Lung densitometry can aid in identifying an exacerbation prone phenotype which may have implications for targeting specific therapies to these individuals. MR ventilation scans have the ability to provide a functional and regional distribution of airflow obstruction offering insight into the airway and parenchymal changes induced by COPD. Micro-CT gives a near microscopic view of the terminal bronchioles and alveoli permitting study of the microarchitecture of the lung ex vivo. Optical coherence tomography can visualize the microstructure of the airway walls (epithelium, smooth muscle, blood vessels, cartilage) permitting real time in vivo as well as longitudinal evaluation of airway changes in patients with COPD.

CONCLUSION

Advanced imaging techniques play a vital role in expanding our current understanding of COPD.

Alpha1-Antitrypsin Deficiency: Transition of Care for the Child With AAT Deficiency into Adulthood

IMPORTANCE

Alpha1-antitrypsin (AAT) deficiency is a common, but an underdiagnosed genetic condition, affecting 1 in 1500 individuals. It can present insidiously with liver disease in children. Although clinical practice guidelines exist for the management of AAT deficiency, especially with regards to pulmonary involvement, there are no published recommendations that specifically relate to the management of the liver disease and monitoring for lung disease associated with this condition, particularly in children.

OBJECTIVE

To review the literature on the management of AAT deficiency-associated liver disease in adults and children.

EVIDENCE REVIEW

A systematic search for articles indexed in PubMed and published was undertaken. Some earlier selected landmark references were included in the review. Search terms included: "alpha1-antitrypsin deficiency"; "liver disease"; "end-stage liver disease"; "liver transplantation" and "preventative management". Recommendations for the management of children with suspected or confirmed AAT deficiency were made according to the Strength of Recommendation Taxonomy scale.

FINDINGS

Liver complications arising from AAT deficiency result from the accumulation of mutated AAT protein within hepatocytes. Liver disease occurs in 10% of children, manifested by cholestasis, pruritus, poor feeding, hepatomegaly, and splenomegaly, but the presentation is highly variable. A diagnostic test for AAT deficiency is recommended for these children. Baseline liver function tests should be obtained to assess for liver involvement; however, the only curative treatment for AAT deficiency-associated liver disease is organ transplantation. Conclusion and Relevance: There should be a greater vigilance for AAT deficiency testing among pediatricians. Diagnosis should prompt assessment of liver involvement. Children with AATdeficiency- associated liver disease should be referred to a liver specialist and monitored throughout their lifetimes for the symptoms of AAT-deficiency-related pulmonary involvement.

Driving pressure and long-term outcomes in moderate/severe acute respiratory distress syndrome

BACKGROUND

Acute respiratory distress syndrome (ARDS) patients may present impaired in lung function and structure after hospital discharge that may be related to mechanical ventilation strategy. The aim of this study was to evaluate the association between functional and structural lung impairment, N-terminal-peptide type III procollagen (NT-PCP-III) and driving pressure during protective mechanical ventilation. It was a secondary analysis of data from randomized controlled trial that included patients with moderate/severe ARDS with at least one follow-up visit performed. We obtained serial measurements of plasma NT-PCP-III levels. Whole-lung computed tomography analysis and pulmonary function test were performed at 1 and 6 months of follow-up. A health-related quality of life survey after 6 months was also performed.

RESULTS

Thirty-three patients were enrolled, and 21 patients survived after 6 months. In extubation day an association between driving pressure and NT-PCP-III was observed. At 1 and 6 months forced vital capacity (FVC) was negatively correlated to driving pressure (p < 0.01). At 6 months driving pressure was associated with lower FVC independently on tidal volume, plateau pressure and baseline static respiratory compliance after adjustments (r² = 0.51, p = 0.02). There was a significant correlation between driving pressure and lung densities and nonaerated/poorly aerated lung volume after 6 months. Driving pressure was also related to general health domain of SF-36 at 6 months.

CONCLUSION

Even in patients ventilated with protective tidal volume, higher driving pressure is associated with worse long-term pulmonary function and structure.

Variability of CT Airways Measurements in COPD Patients Between Morning and Afternoon: Comparisons to Variability of Spirometric Measurements

RATIONALE AND OBJECTIVES

Computed tomography (CT) airways measurements can be used as surrogates to spirometric measurements for assessing bronchodilation in a particular patient with chronic obstructive pulmonary disease. Although spirometric measurements show variations within the opening hours of a hospital department, we aimed to compare the variability of CT airways measurements between morning and afternoon in patients with chronic obstructive pulmonary disease to that of spirometric measurements.

MATERIALS AND METHODS

Twenty patients had pulmonary function tests and CT around 8 am and 4 pm. Luminal area (LA) and wall thickness (WT) of third and fourth generation airways were measured twice by three readers. The percentage of airway area occupied by the wall (WA%) and the square root of wall area at an internal perimeter of 10 mm (√WAPi10) were calculated. The effects of examination time, reader, and measurement session on CT airways measurements were assessed, and the variability of these measurements was compared to that of spirometric measurements.

RESULTS

Variability of LA^3rd and LA^4th was greater than that of spirometric measurements (P values ranging from <.001 to .033). There was no examination time effect on √WAPi10, WT^3rd, LA^4th, or WA%^4th (P values ranging from .102 to .712). There was a reader effect on all CT airways measurements (P values ranging from <.001 to .028), except in WT^3rd (P> .999). There was no effect of measurement session on any CT airway measurement (P values ranging from .535 to >.999).

CONCLUSION

As the variability of LA^3rd and LA^4th is greater than that of spirometric measurements, clinical studies should include cohorts with larger numbers of patients when considering LA than when considering spirometric measurements as end points.

Safety of biweekly α1-antitrypsin treatment in the RAPID programme

α₁-antitrypsin (α₁-AT) deficiency is a hereditary disorder characterised by an abnormally low concentration of functional α₁-AT in blood and tissues [1]. The primary role of α₁-AT is to protect elastin-containing tissues, most notably the lung, against the destructive activity of proteolytic enzymes [2]. Patients with severe α₁-AT deficiency present with serum α₁-AT concentrations <11 μM and are prone to destruction of the lung tissue, often developing respiratory symptoms and emphysema in the fourth or fifth decade of life [3, 4].

Administration of 120 mg·kg⁻¹ α₁-antitrypsin on a biweekly basis was safe and well toleratedhttp://ow.ly/CVbz30lUBum

Intravenous Alpha-1 Antitrypsin Therapy for Alpha-1 Antitrypsin Deficiency: The Current State of the Evidence

Alpha-1 antitrypsin deficiency (AATD) is a largely monogenetic disorder associated with a high risk for the development of chronic obstructive pulmonary disease (COPD) and cirrhosis. Intravenous alpha-1 antitrypsin (AAT) therapy has been available for the treatment of individuals with AATD and COPD since the late 1980s. Initial Food and Drug Administration (FDA) approval was granted based on biochemical efficacy. Following its approval, the FDA, scientific community and third-party payers encouraged manufacturers of AAT therapy to determine its clinical efficacy. This task has proved challenging because AATD is a rare, orphan disorder comprised of individuals who are geographically dispersed and infrequently identified. In addition, robust clinical trial outcomes have been lacking until recently. This review provides an update on the evidence for the clinical efficacy of intravenous AAT therapy for patients with AATD-related emphysema.

Advances in managing COPD related to α1 -antitrypsin deficiency: An under-recognized genetic disorder

α1 -Antitrypsin deficiency (AATD) predisposes individuals to chronic obstructive pulmonary disease (COPD) and liver disease. Despite being commonly described as rare, AATD is under-recognized, with less than 10% of cases identified. The following is a comprehensive review of AATD, primarily for physicians who treat COPD or asthma, covering the genetics, epidemiology, clinical presentation, screening and diagnosis, and treatments of AATD. For patients presenting with liver and/or lung disease, screening and diagnostic tests are the only methods to determine whether the disease is related to AATD. Screening guidelines have been established by organizations such as the World Health Organization, European Respiratory Society, and American Thoracic Society. High-risk groups, including individuals with COPD, nonresponsive asthma, bronchiectasis of unknown etiology, or unexplained liver disease, should be tested for AATD. Current treatment options include augmentation therapy with purified AAT for patients with deficient AAT levels and significant lung disease. Recent trial data suggest that lung tissue is preserved by augmentation therapy, and different dosing schedules are currently being investigated. Effective management of AATD and related diseases also includes aggressive avoidance of smoking and biomass burning, vaccinations, antibiotics, exercise, good diet, COPD medications, and serial assessment.

Therapeutic potential of alpha-1 antitrypsin in human disease

Alpha-1 antitrypsin (AAT), an alpha globulin glycoprotein, is a member of the serine protease inhibitor (serpin) superfamily. The clinical significance of AAT is highlighted by AAT deficiency. Genetic deficiency of AAT can present as several neutrophilic diseases associated with emphysema, liver cirrhosis, panniculitis, and systemic vasculitis. Recently, animal and human studies have shown that AAT can control inflammatory, immunological, and tissue-protective responses. In addition, AAT treatment can prevent overt hyperglycemia, increase insulin secretion, and reduce cytokine-mediated apoptosis of pancreatic β-cells in diabetes. These multifunctional roles of AAT draw attention to the glycoprotein's therapeutic potential for many inflammatory and autoimmune diseases beyond AAT deficiency. As underlying mechanisms, recent studies have suggested the importance of serine protease inhibitory activity of AAT in obesity-associated insulin resistance, chronic obstructive pulmonary disease, and cystic fibrosis. In this review, we explore the multiple functions of AAT, in particular, the anti-inflammatory and serine protease inhibitory functions, and AAT's therapeutic potential in a variety of human diseases through published literature.

New Therapeutic Targets for Alpha-1 Antitrypsin Deficiency

Alpha-1antitrypsin deficiency (AATD) results from the intracellular polymerization and retention of mutant alpha-1antitrypsin (AAT) within the endoplasmic reticulum of hepatocytes. This causes cirrhosis whilst the deficiency of circulating AAT predisposes to early onset emphysema. This is an exciting time for researchers in the field with the development of novel therapies based on understanding the pathobiology of disease. I review here augmentation therapy to prevent the progression of lung disease and a range of approaches to treat the liver disease associated with the accumulation of mutant AAT: modifying proteostasis networks that are activated by Z AAT polymers, stimulating autophagy, small interfering RNA and small molecules to block intracellular polymerization, and stem cell technology to correct the genetic defect that underlies AATD.

Health status decline in α-1 antitrypsin deficiency: a feasible outcome for disease modifying therapies?

Background

Trials of disease modifying therapies in Chronic Obstructive Pulmonary Disease (COPD) provide challenges for detecting physiological and patient centred outcomes. The purpose of the current study was to monitor decline in health status in Alpha-1 antitrypsin deficiency (AATD) and determine its’ relationship to conventional physiology.

Methods

Patients recruited to the UK-AATD database with a median follow up of 7 years (IQR 5–10) were studied to determine annual change in St George’s Respiratory Questionnaire (SGRQ), FEV₁, gas transfer and their feasibility of use in future trials.

Results

Annual decline in SGRQ had a wide range, was greater for patients with established COPD and correlated with decline in FEV₁ (p < 0.0001). Total score decline was greater (p < 0.05) for those with accelerated FEV₁ decline (median = 1.07 points/year) compared to those without (median = 0.51). Power calculations indicated effective intervention would not achieve MCID for the SGRQ unless the timeframe was extended for up to 8 years. More than 5000 patients/arm would be required for a statistically significant modest effect over 3 years even in those with rapid FEV₁ decline.

Conclusion

Despite AATD being a rapidly declining form of COPD, deterioration in SGRQ was slow consistent with ageing and the chronic nature of disease progression. Power calculations indicate the numbers needed to detect a difference with disease modifying therapies would be prohibitive especially in this rare cause of COPD. These data have important implications for future study design of disease modifying therapies even in COPD not associated with AATD.

Electronic supplementary material

The online version of this article (10.1186/s12931-018-0844-6) contains supplementary material, which is available to authorized users.