Evaluation of COPD Longitudinally to Identify Predictive Surrogate End-points (ECLIPSE)

Altered gene expression in blood and sputum in COPD frequent exacerbators in the ECLIPSE cohort

Patients with chronic obstructive pulmonary disease (COPD) who are defined as frequent exacerbators suffer with 2 or more exacerbations every year. The molecular mechanisms responsible for this phenotype are poorly understood. We investigated gene expression profile patterns associated with frequent exacerbations in sputum and blood cells in a well-characterised cohort. Samples from subjects from the ECLIPSE COPD cohort were used; sputum and blood samples from 138 subjects were used for microarray gene expression analysis, while blood samples from 438 subjects were used for polymerase chain reaction (PCR) testing. Using microarray, 150 genes were differentially expressed in blood (>±1.5 fold change, p≤0.01) between frequent compared to non-exacerbators. In sputum cells, only 6 genes were differentially expressed. The differentially regulated genes in blood included downregulation of those involved in lymphocyte signalling and upregulation of pro-apoptotic signalling genes. Multivariate analysis of the microarray data followed by confirmatory PCR analysis identified 3 genes that predicted frequent exacerbations; B3GNT, LAF4 and ARHGEF10. The sensitivity and specificity of these 3 genes to predict the frequent exacerbator phenotype was 88% and 33% respectively. There are alterations in systemic immune function associated with frequent exacerbations; down-regulation of lymphocyte function and a shift towards pro-apoptosis mechanisms are apparent in patients with frequent exacerbations.

Genetic susceptibility for chronic bronchitis in chronic obstructive pulmonary disease

Background

Chronic bronchitis (CB) is one of the classic phenotypes of COPD. The aims of our study were to investigate genetic variants associated with COPD subjects with CB relative to smokers with normal spirometry, and to assess for genetic differences between subjects with CB and without CB within the COPD population.

Methods

We analyzed data from current and former smokers from three cohorts: the COPDGene Study; GenKOLS (Bergen, Norway); and the Evaluation of COPD Longitudinally to Identify Predictive Surrogate Endpoints (ECLIPSE). CB was defined as having a cough productive of phlegm on most days for at least 3 consecutive months per year for at least 2 consecutive years. CB COPD cases were defined as having both CB and at least moderate COPD based on spirometry. Our primary analysis used smokers with normal spirometry as controls; secondary analysis was performed using COPD subjects without CB as controls. Genotyping was performed on Illumina platforms; results were summarized using fixed-effect meta-analysis.

Results

For CB COPD relative to smoking controls, we identified a new genome-wide significant locus on chromosome 11p15.5 (rs34391416, OR = 1.93, P = 4.99 × 10^-8) as well as significant associations of known COPD SNPs within FAM13A. In addition, a GWAS of CB relative to those without CB within COPD subjects showed suggestive evidence for association on 1q23.3 (rs114931935, OR = 1.88, P = 4.99 × 10^-7).

Conclusions

We found genome-wide significant associations with CB COPD on 4q22.1 (FAM13A) and 11p15.5 (EFCAB4A, CHID1 and AP2A2), and a locus associated with CB within COPD subjects on 1q23.3 (RPL31P11 and ATF6). This study provides further evidence that genetic variants may contribute to phenotypic heterogeneity of COPD.

Trial registration

ClinicalTrials.gov NCT00608764, NCT00292552

Electronic supplementary material

The online version of this article (doi:10.1186/s12931-014-0113-2) contains supplementary material, which is available to authorized users.

Integrative genomics of chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is a complex disease with both environmental and genetic determinants, the most important of which is cigarette smoking. There is marked heterogeneity in the development of COPD among persons with similar cigarette smoking histories, which is likely partially explained by genetic variation. Genomic approaches such as genomewide association studies and gene expression studies have been used to discover genes and molecular pathways involved in COPD pathogenesis; however, these "first generation" omics studies have limitations. Integrative genomic studies are emerging which can combine genomic datasets to further examine the molecular underpinnings of COPD. Future research in COPD genetics will likely use network-based approaches to integrate multiple genomic data types in order to model the complex molecular interactions involved in COPD pathogenesis. This article reviews the genomic research to date and offers a vision for the future of integrative genomic research in COPD.

An aberrant leukotriene A4 hydrolase-proline-glycine-proline pathway in the pathogenesis of chronic obstructive pulmonary disease

RATIONALE

Chronic neutrophilic inflammation is a hallmark in the pathogenesis of chronic obstructive pulmonary disease (COPD) and persists after cigarette smoking has stopped. Mechanisms involved in this ongoing inflammatory response have not been delineated.

OBJECTIVES

We investigated changes to the leukotriene A4 hydrolase (LTA4H)-proline-glycine-proline (PGP) pathway and chronic inflammation in the development of COPD.

METHODS

A/J mice were exposed to air or cigarette smoke for 22 weeks followed by bronchoalveolar lavage and lung and cardiac tissue analysis. Two human cohorts were used to analyze changes to the LTA4H-PGP pathway in never smokers, control smokers, COPD smokers, and COPD former smokers. PGP/AcPGP and LTA4H aminopeptidase activity were detected by mass spectroscopy, LTA4H amounts were detected by ELISA, and acrolein was detected by Western blot.

MEASUREMENTS AND MAIN RESULTS

Mice exposed to cigarette smoke developed emphysema with increased PGP, neutrophilic inflammation, and selective inhibition of LTA4H aminopeptidase, which ordinarily degrades PGP. We recapitulated these findings in smokers with and without COPD. PGP and AcPGP are closely associated with cigarette smoke use. Once chronic inflammation is established, changes to LTA4H aminopeptidase remain, even in the absence of ongoing cigarette use. Acrolein modifies LTA4H and inhibits aminopeptidase activity to the same extent as cigarette smoke.

CONCLUSIONS

These results demonstrate a novel pathway of aberrant regulation of PGP/AcPGP, suggesting this inflammatory pathway may be intimately involved in disease progression in the absence of ongoing cigarette smoke exposure. We highlight a mechanism by which acrolein potentiates neutrophilic inflammation through selective inhibition of LTA4H aminopeptidase activity. Clinical trial registered with www.clinicaltrials.gov (NCT 00292552).

Survival in COPD: impact of lung dysfunction and comorbidities

Chronic obstructive pulmonary disease (COPD) is a major cause of morbidity and mortality in industrialized countries. Recent studies investigated the impact of comorbidities on the survival in COPD, but most of them lacked a referent group of comorbidity-matched, nonobstructed individuals.We examined the 10-year mortality in a sample of 200 COPD patients and 201 nonobstructed controls. They were part of a larger cohort enrolled in a European case-control study aimed at assessing genetic susceptibility to COPD. By design, the COPD group included patients with a forced expiratory volume in 1 second (FEV1) ≤70% predicted. Cases and controls were matched on age, sex, and cumulative smoking history, and shared a nearly identical prevalence of cardiovascular and metabolic disorders. We estimated the hazard of death with Cox regression and percentiles of survival with Laplace regression. COPD was the main exposure variable of interest. Five comorbidities (hypertension, coronary artery disease, prior myocardial infarction, chronic heart failure, and diabetes) were included as covariates in multiple regression models.The all-cause mortality rate was significantly higher in cases than in controls (43% vs 16%, P < 0.001). The unadjusted hazard of death for COPD was 3-fold higher than the referent category (P < 0.001), and remained nearly unchanged after introducing the 5 comorbidities in multiple regression. Patients with COPD had significantly shorter survival percentiles than comorbidity-matched controls (P < 0.001). Notably, 15% of the nonobstructed controls died by 10.3 years into the study; the same proportion of COPD patients had died some 6 years earlier, at 4.6 years.In a separate analysis, we split the whole sample into 2 groups based on the lower tertile of FEV1 and carbon monoxide lung diffusing capacity (DLCO). The hazard of death for COPD patients with low FEV1 and DLCO was nearly 3.5-fold higher than in all the others (P < 0.001), and decreased only slightly after introducing age and chronic heart failure as relevant covariates.COPD is a strong predictor of reduced survival independently of coexisting cardiovascular and metabolic disorders. Efforts should be made to identify patients at risk and to ensure adherence to prescribed therapeutic regimens.

DNAH5 is associated with total lung capacity in chronic obstructive pulmonary disease

BACKGROUND

Chronic obstructive pulmonary disease (COPD) is characterized by expiratory flow limitation, causing air trapping and lung hyperinflation. Hyperinflation leads to reduced exercise tolerance and poor quality of life in COPD patients. Total lung capacity (TLC) is an indicator of hyperinflation particularly in subjects with moderate-to-severe airflow obstruction. The aim of our study was to identify genetic variants associated with TLC in COPD.

METHODS

We performed genome-wide association studies (GWASs) in white subjects from three cohorts: the COPDGene Study; the Evaluation of COPD Longitudinally to Identify Predictive Surrogate Endpoints (ECLIPSE); and GenKOLS (Bergen, Norway). All subjects were current or ex-smokers with at least moderate airflow obstruction, defined by a ratio of forced expiratory volume in 1 second to forced vital capacity (FEV1/FVC) <0.7 and FEV1 < 80% predicted on post-bronchodilator spirometry. TLC was calculated by using volumetric computed tomography scans at full inspiration (TLCCT). Genotyping in each cohort was completed, with statistical imputation of additional markers. To find genetic variants associated with TLCCT, linear regression models were used, with adjustment for age, sex, pack-years of smoking, height, and principal components for genetic ancestry. Results were summarized using fixed-effect meta-analysis.

RESULTS

Analysis of a total of 4,543 COPD subjects identified one genome-wide significant locus on chromosome 5p15.2 (rs114929486, β = 0.42L, P = 4.66 × 10-8).

CONCLUSIONS

In COPD, TLCCT was associated with a SNP in dynein, axonemal, heavy chain 5 (DNAH5), a gene in which genetic variants can cause primary ciliary dyskinesia. DNAH5 could have an effect on hyperinflation in COPD.

Persistent systemic inflammation and symptoms of depression among patients with COPD in the ECLIPSE cohort

BACKGROUND

Depression is highly prevalent among patients with Chronic Obstructive Pulmonary Disease (COPD). The relationship of depression with systemic inflammation in COPD remains unknown. The objective of this observational study was to compare depression scores at baseline and after 36 months follow-up between COPD patients with persistent systemic inflammation (PSI) and never inflamed patients (NI) in the ECLIPSE cohort.

METHODS

The ECLIPSE study included 2164 COPD patients. Parameters assessed at baseline and at 36 months follow-up included: demographics, clinical characteristics and symptoms of depression (Center for Epidemiologic Studies of Depression, CES-D). Patients classified as NI had zero and patients with PSI had ≥2 inflammatory biomarkers (white blood cell count, hsCRP, IL-6, and fibrinogen) in the upper quartile, at baseline and 12 months later.

FINDINGS

350 patients (29.1%) were NI and 131 patients (10.9%) had PSI. At baseline, mean CES-D score was higher in patients with PSI than in NI patients (11.7 (8.6) vs. 9.2 (8.9) points, p = 0.01). Differences were not confirmed after adjustment for possible confounders (β (95% CI) = 0.02 (-3.87 to 15.29), adjusted p = 0.98). At 36 months follow-up, CES-D scores were comparable in PSI and NI patients (12.2 (9.3) vs. 10.5 (9.0) points, p = 0.08) as were their temporal changes (0.5 (8.3) vs. 1.3 (7.9) points, p = 0.30).

CONCLUSION

The ECLIPSE study does not support a strong relationship between PSI and symptoms of depression at baseline and after 36 months follow-up in COPD.

FUNDING

The study was sponsored by GlaxoSmithKline.

The application of impulse oscillation system for the evaluation of treatment effects in patients with COPD

There are only a few reports of the use of impulse oscillation system (IOS) for the evaluation of COPD treatment. In this study, we applied IOS and spirometry to evaluate the effectiveness of fluticasone propionate and salmeterol (SFC) combined with tiotropium (TIO) in COPD patients. Following a 4-week run-in period with TIO (18 μg once daily) treatment, COPD patients were randomized to SFC (250/50 μg twice daily; SFC+TIO group, n=25), or TIO alone (TIO group, n=31). Pulmonary functions were recorded by IOS and spirometry before and after the study period. The SFC+TIO group showed significant improvements in inspiratory resistance at 5 Hz and resonant frequency, as well as in FVC and FEV1, after the 12-week treatment (p<0.05). Since there were no significant correlations between improvements in IOS measurements and FVC or FEV1, IOS may provide a physiological point of view that is different from spirometry and seemed to be applicable as an additional assessment tool targeting COPD patients.

Hyperpolarized 3He and 129Xe magnetic resonance imaging apparent diffusion coefficients: physiological relevance in older never- and ex-smokers

Noble gas pulmonary magnetic resonance imaging (MRI) is transitioning away from (3)He to (129)Xe gas, but the physiological/clinical relevance of (129)Xe apparent diffusion coefficient (ADC) parenchyma measurements is not well understood. Therefore, our objective was to generate (129)Xe MRI ADC for comparison with (3)He ADC and with well-established measurements of alveolar structure and function in older never-smokers and ex-smokers with chronic obstructive pulmonary disease (COPD). In four never-smokers and 10 COPD ex-smokers, (3)He (b = 1.6 sec/cm(2)) and (129)Xe (b = 12, 20, and 30 sec/cm(2)) ADC, computed tomography (CT) density-threshold measurements, and the diffusing capacity for carbon monoxide (DLCO) were measured. To understand regional differences, the anterior-posterior (APG) and superior-inferior (∆SI) ADC differences were evaluated. Compared to never-smokers, COPD ex-smokers showed greater (3)He ADC (P = 0.006), (129)Xe ADCb12 (P = 0.006), and ADCb20 (P = 0.006), but not for ADCb30 (P > 0.05). Never-smokers and COPD ex-smokers had significantly different APG for (3)He ADC (P = 0.02), (129)Xe ADCb12 (P = 0.006), and ADCb20 (P = 0.01), but not for ADCb30 (P > 0.05). ∆SI for never- and ex-smokers was significantly different for (3)He ADC (P = 0.046), but not for (129)Xe ADC (P > 0.05). There were strong correlations for DLCO with (3)He ADC and (129)Xe ADCb12 (both r = -0.95, P < 0.05); in a multivariate model (129)Xe ADCb12 was the only significant predictor of DLCO (P = 0.049). For COPD ex-smokers, CT relative area <-950 HU (RA950) correlated with (3)He ADC (r = 0.90, P = 0.008) and (129)Xe ADCb12 (r = 0.85, P = 0.03). In conclusion, while (129)Xe ADCb30 may be appropriate for evaluating subclinical or mild emphysema, in this small group of never-smokers and ex-smokers with moderate-to-severe emphysema, (129)Xe ADCb12 provided a physiologically appropriate estimate of gas exchange abnormalities and alveolar microstructure.

Should we view chronic obstructive pulmonary disease differently after ECLIPSE? A clinical perspective from the study team

RATIONALE

Chronic obstructive pulmonary disease (COPD) seems to be a heterogeneous disease with a variable course.

OBJECTIVES

We wished to characterize the heterogeneity and variability of COPD longitudinally.

METHODS

In the Evaluation of COPD Longitudinally to Identify Predictive Surrogate Endpoints (ECLIPSE) study of 2,164 patients with clinically stable COPD, 337 smokers with normal lung function, and 245 never-smokers, we measured a large number of clinical parameters, lung function, exercise tolerance, biomarkers, and amount of emphysema by computed tomography. All three groups were followed for 3 years.

MEASUREMENTS AND MAIN RESULTS

We found a striking heterogeneity among patients with COPD, with poor correlations between FEV1, symptoms, quality of life, functional outcomes, and biomarkers. Presence of systemic inflammation was found in only a limited proportion of patients, and did not relate to baseline characteristics or disease progression, but added prognostic value for predicting mortality. Exacerbations tracked over time and added to the concept of the "frequent exacerbator phenotype." Disease course was very variable, with close to a third of patients not progressing at all. Risk factors for 3-year change in both FEV1 and lung density were assessed. For FEV1 decline, continued smoking and presence of emphysema were the strongest predictors of progression; club cell protein was found to be a potential biomarker for disease activity. For progression of emphysema, the strongest predictors were continued smoking and female sex.

CONCLUSIONS

By following a large, well characterized cohort of patients with COPD over 3 years, we have a clearer picture of a heterogeneous disease with clinically important subtypes ("phenotypes") and a variable and not inherently progressive course. Clinical trial registered with www.clinicaltrials.gov (NCT00292552).

Analyzing networks of phenotypes in complex diseases: methodology and applications in COPD

Background

The investigation of complex disease heterogeneity has been challenging. Here, we introduce a network-based approach, using partial correlations, that analyzes the relationships among multiple disease-related phenotypes.

Results

We applied this method to two large, well-characterized studies of chronic obstructive pulmonary disease (COPD). We also examined the associations between these COPD phenotypic networks and other factors, including case-control status, disease severity, and genetic variants. Using these phenotypic networks, we have detected novel relationships between phenotypes that would not have been observed using traditional epidemiological approaches.

Conclusion

Phenotypic network analysis of complex diseases could provide novel insights into disease susceptibility, disease severity, and genetic mechanisms.

Microfibrillar-associated protein 4: a potential biomarker of chronic obstructive pulmonary disease

BACKGROUND

Microfibrillar-associated protein 4 (MFAP4) is a matricellular glycoprotein that co-localises with elastic fibres and is highly expressed in the lungs. The aim of this study was to test the hypothesis that plasma MFAP4 (pMFAP4) reflects clinical outcomes in chronic obstructive pulmonary disease (COPD).

METHODS

pMFAP4 was measured by an AlphaLISA immunoassay in stable COPD (n = 69) at baseline and at follow-up until 24 months after inclusion and in acute exacerbations of COPD (AECOPD) (n = 14) at baseline and until 6 months after inclusion.

RESULTS

The majority of patients (89%) were in GOLD II and III. Multiple linear regressions showed positive associations between pMFAP4 and the Global initiative for Obstructive Lung Disease (GOLD) grade (p = 0.01), modified Medical Research Council score (p < 0.0001) and BODE index (p = 0.04). Negative associations were found with 6-min walking distance (p = 0.04) and bronchodilator-induced reversibility (p = 0.02). The pMFAP4 levels varied less than 25% between the baseline and a 3 month follow-up in 83% of the patients. The pMFAP4 levels appeared unaffected in the acute phase of severe AECOPD but rose to an increased stable level within one month after hospitalization.

CONCLUSION

Increased pMFAP4 was associated to the severity in COPD and has the potential to serve as a stable disease biomarker. This observation warrants confirmation in a larger longitudinal COPD population.

Co-morbidities are the key nominators of the health related quality of life in mild and moderate COPD

Background

Co-morbidities are common in chronic obstructive pulmonary disease (COPD). We assessed the contribution of common co-morbidities on health related quality of life (HRQoL) among COPD patients.

Methods

Using both generic (15D) and respiratory-specific (AQ20) instruments, HRQoL was assessed in a hospital based COPD population (N = 739, 64% males, mean age 64 years, SD 7 years) in this observational study with inferential analysis. The prevalence of their co-morbidities was compared with those of 5000 population controls. The patients represented all severity stages of COPD and the patterns of common concomitant disorders differed between patients.

Results

Co-morbidities such as psychiatric conditions, alcohol abuse, cardiovascular diseases, and diabetes were more common among COPD patients than in age and gender matched controls. Psychiatric conditions and alcohol abuse were the strongest determinants of HRQoL in COPD and could be detected by both 15D (Odds Ratio 4.7 and 2.3 respectively) and AQ20 (OR 2.0 and 3.0) instruments. Compared to respiratory specific AQ20, generic 15D was more sensitive to the effects of comorbidities while AQ20 was slightly more sensitive for the low FEV₁. FEV₁ was a strong determinant of HRQoL only at more severe stages of disease (FEV₁ < 40% of predicted). Poor HRQoL also predicted death during the next five years.

Conclusions

The results suggest that co-morbidities may impair HRQoL at an early stage of the disease, while bronchial obstruction becomes a significant determinant of HRQoL only in severe COPD.

Moving towards patient-centered medicine for COPD management: multidimensional approaches versus phenotype-based medicine--a critical view

For decades, chronic obstructive pulmonary disease (COPD) has been considered a relentlessly progressive disease in which the deterioration of lung function is associated with an increase in symptoms, interrupted only by periods of exacerbation. However, this paradigm of COPD severity based on FEV1 has been challenged by currently available evidence. So far, three main approaches, though with contradictory aspects, have been proposed in order to address the complexity of COPD as well as to develop appropriate diagnostic, prognostic and therapeutic strategies for the disease: 1) the use of independent, clinically relevant variables, 2) the use of multidimensional indices, and 3) disease approaches based on clinical phenotypes. Multivariable systems seem superior to FEV1 in predicting prognosis and defining disease severity. However, selection of variables available from current literature must be confronted with issues of medical practice. Future evidence will be needed to reveal their effective relationship with disease long-term prognosis and to demonstrate the most adequate cutoff values to be used in clinical settings. Multidimensional scores provide a good prognostic instrument for the identification of patients with a particular degree of disease severity. Clinical phenotyping can help clinicians identify the patients who respond to specific pharmacological interventions; however, there is some controversy about the phenotypes to select and their long-term implications. Although these approaches are not perfect, they represent the first step towards patient-centered medicine for COPD. In the near-future, these different approaches should converge towards one new field to focus on the better management of COPD patients.

Airway wall area derived from 3-dimensional computed tomography analysis differs among lung lobes in male smokers

Background

It is time-consuming to obtain the square root of airway wall area of the hypothetical airway with an internal perimeter of 10 mm (√Aaw at Pi10), a comparable index of airway dimensions in chronic obstructive pulmonary disease (COPD), from all airways of the whole lungs using 3-dimensional computed tomography (CT) analysis. We hypothesized that √Aaw at Pi10 differs among the five lung lobes and √Aaw at Pi10 derived from one certain lung lobe has a high level of agreement with that derived from the whole lungs in smokers.

Methods

Pulmonary function tests and chest volumetric CTs were performed in 157 male smokers (102 COPD, 55 non-COPD). All visible bronchial segments from the 3^rd to 5^th generations were segmented and measured using commercially available 3-dimensional CT analysis software. √Aaw at Pi10 of each lung lobe was estimated from all measurable bronchial segments of that lobe.

Results

Using a mixed-effects model, √Aaw at Pi10 differed significantly among the five lung lobes (R² = 0.78, P<0.0001). The Bland-Altman plots show that √Aaw at Pi10 derived from the right or left upper lobe had a high level of agreement with that derived from the whole lungs, while √Aaw at Pi10 derived from the right or left lower lobe did not.

Conclusion

In male smokers, CT-derived airway wall area differs among the five lung lobes, and airway wall area derived from the right or left upper lobe is representative of the whole lungs.

Evaluating the role of inflammation in chronic airways disease: the ERICA study

Extrapulmonary manifestations are recognized to be of increasing clinical importance in Chronic Obstructive Pulmonary disease. To investigate cardiovascular and skeletal muscle manifestations of COPD, we developed a unique UK consortium funded by the Technology Strategy Board and Medical Research Council comprising industry in partnership with 5 academic centres. ERICA (Evaluating the Role of Inflammation in Chronic Airways disease) is a prospective, longitudinal, observational study investigating the prevalence and significance of cardiovascular and skeletal muscle manifestations of COPD in 800 subjects. Six monthly follow up will assess the predictive value of plasma fibrinogen, cardiovascular abnormalities and skeletal muscle weakness for death or hospitalization. As ERICA is a multicentre study, to ensure data quality we sought to minimise systematic observer error due to variations in investigator skill, or adherence to operating procedures, by staff training followed by assessment of inter- and intra-observer reliability of the four key measurements used in the study: pulse wave velocity (PWV), carotid intima media thickness (CIMT), quadriceps maximal voluntary contraction force (QMVC) and 6-minute walk distance (6MWT). This report describes the objectives and methods of the ERICA trial, as well as the inter- and intra-observer reliability of these measurements.

Design of the Subpopulations and Intermediate Outcomes in COPD Study (SPIROMICS)

Subpopulations and Intermediate Outcomes in COPD Study (SPIROMICS) is a multicentre observational study of chronic obstructive pulmonary disease (COPD) designed to guide future development of therapies for COPD by providing robust criteria for subclassifying COPD participants into groups most likely to benefit from a given therapy during a clinical trial, and identifying biomarkers/phenotypes that can be used as intermediate outcomes to reliably predict clinical benefit during therapeutic trials. The goal is to enrol 3200 participants in four strata. Participants undergo a baseline visit and three annual follow-up examinations, with quarterly telephone calls. Adjudication of exacerbations and mortality will be undertaken.

Susceptibility to chronic mucus hypersecretion, a genome wide association study

Background

Chronic mucus hypersecretion (CMH) is associated with an increased frequency of respiratory infections, excess lung function decline, and increased hospitalisation and mortality rates in the general population. It is associated with smoking, but it is unknown why only a minority of smokers develops CMH. A plausible explanation for this phenomenon is a predisposing genetic constitution. Therefore, we performed a genome wide association (GWA) study of CMH in Caucasian populations.

Methods

GWA analysis was performed in the NELSON-study using the Illumina 610 array, followed by replication and meta-analysis in 11 additional cohorts. In total 2,704 subjects with, and 7,624 subjects without CMH were included, all current or former heavy smokers (≥20 pack-years). Additional studies were performed to test the functional relevance of the most significant single nucleotide polymorphism (SNP).

Results

A strong association with CMH, consistent across all cohorts, was observed with rs6577641 (p = 4.25×10⁻⁶, OR = 1.17), located in intron 9 of the special AT-rich sequence-binding protein 1 locus (SATB1) on chromosome 3. The risk allele (G) was associated with higher mRNA expression of SATB1 (4.3×10⁻⁹) in lung tissue. Presence of CMH was associated with increased SATB1 mRNA expression in bronchial biopsies from COPD patients. SATB1 expression was induced during differentiation of primary human bronchial epithelial cells in culture.

Conclusions

Our findings, that SNP rs6577641 is associated with CMH in multiple cohorts and is a cis-eQTL for SATB1, together with our additional observation that SATB1 expression increases during epithelial differentiation provide suggestive evidence that SATB1 is a gene that affects CMH.

A diVIsive Shuffling Approach (VIStA) for gene expression analysis to identify subtypes in Chronic Obstructive Pulmonary Disease

Background

An important step toward understanding the biological mechanisms underlying a complex disease is a refined understanding of its clinical heterogeneity. Relating clinical and molecular differences may allow us to define more specific subtypes of patients that respond differently to therapeutic interventions.

Results

We developed a novel unbiased method called diVIsive Shuffling Approach (VIStA) that identifies subgroups of patients by maximizing the difference in their gene expression patterns. We tested our algorithm on 140 subjects with Chronic Obstructive Pulmonary Disease (COPD) and found four distinct, biologically and clinically meaningful combinations of clinical characteristics that are associated with large gene expression differences. The dominant characteristic in these combinations was the severity of airflow limitation. Other frequently identified measures included emphysema, fibrinogen levels, phlegm, BMI and age. A pathway analysis of the differentially expressed genes in the identified subtypes suggests that VIStA is capable of capturing specific molecular signatures within in each group.

Conclusions

The introduced methodology allowed us to identify combinations of clinical characteristics that correspond to clear gene expression differences. The resulting subtypes for COPD contribute to a better understanding of its heterogeneity.

Acute Exacerbation and Respiratory InfectionS in COPD (AERIS): protocol for a prospective, observational cohort study

INTRODUCTION

The aetiology of acute exacerbations of chronic obstructive pulmonary disease (COPD) remains incompletely understood and strategies for treatment and prevention have not altered significantly for many years. Improved understanding of the role of respiratory pathogens in acute exacerbations of COPD (AECOPD) is required and the use of molecular microbiological techniques may lead to insights into host-pathogen interactions and the development of more targeted therapeutic approaches.

METHODS AND ANALYSES

Acute Exacerbation and Respiratory InfectionS in COPD (AERIS) is a longitudinal epidemiological study to assess how changes in the COPD airway microbiome contribute to the incidence and severity of AECOPD. Patients with COPD aged 40-85 are followed monthly for 2 years, and reviewed within 72 h of onset of symptoms of AECOPD. Exacerbations are detected using daily electronic diary cards. Blood, sputum, nasopharyngeal and urine samples are collected at prespecified timepoints. Molecular diagnostic and typing techniques are used to describe the dynamics of airway infection during AECOPD and stable disease, and associations with clinical outcome. This study aims to refine the case definition of AECOPD to reflect the possible microbiological aetiology. AERIS will assess the impact of AECOPD on health-related quality of life and healthcare resource utilisation, and the possible interactions between nutritional status, infection and immune responses.

ETHICS AND DISSEMINATION

AERIS is conducted in accordance with the Declaration of Helsinki and Good Clinical Practice, and has been approved by the institutional ethics and review board. All participants must provide written informed consent. The results obtained will be disseminated at international medical conferences and in peer-reviewed publications.

DISCUSSION

Few other studies have addressed the complexity of the microbiological and systemic components of COPD or employed real-time electronic tracking of symptoms to identify AECOPD and potential aetiological triggers.

RESULTS

Results of AERIS will increase our understanding of the contribution of pathogens to AECOPD, potentially leading to new targeted therapeutic and preventative interventions.

TRIAL REGISTRATION NUMBER

ClinicalTrials.gov NCT01360398.

Primary care COPD patients compared with large pharmaceutically-sponsored COPD studies: an UNLOCK validation study

Background

Guideline recommendations for chronic obstructive pulmonary disease (COPD) are based on the results of large pharmaceutically-sponsored COPD studies (LPCS). There is a paucity of data on disease characteristics at the primary care level, while the majority of COPD patients are treated in primary care.

Objective

We aimed to evaluate the external validity of six LPCS (ISOLDE, TRISTAN, TORCH, UPLIFT, ECLIPSE, POET-COPD) on which current guidelines are based, in relation to primary care COPD patients, in order to inform future clinical practice guidelines and trials.

Methods

Baseline data of seven primary care databases (n = 3508) from Europe were compared to baseline data of the LPCS. In addition, we examined the proportion of primary care patients eligible to participate in the LPCS, based on inclusion criteria.

Results

Overall, patients included in the LPCS were younger (mean difference (MD)-2.4; p = 0.03), predominantly male (MD 12.4; p = 0.1) with worse lung function (FEV1% MD -16.4; p<0.01) and worse quality of life scores (SGRQ MD 15.8; p = 0.01). There were large differences in GOLD stage distribution compared to primary care patients. Mean exacerbation rates were higher in LPCS, with an overrepresentation of patients with ≥1 and ≥2 exacerbations, although results were not statistically significant. Our findings add to the literature, as we revealed hitherto unknown GOLD I exacerbation characteristics, showing 34% of mild patients had ≥1 exacerbations per year and 12% had ≥2 exacerbations per year. The proportion of primary care patients eligible for inclusion in LPCS ranged from 17% (TRISTAN) to 42% (ECLIPSE, UPLIFT).

Conclusion

Primary care COPD patients stand out from patients enrolled in LPCS in terms of gender, lung function, quality of life and exacerbations. More research is needed to determine the effect of pharmacological treatment in mild to moderate patients. We encourage future guideline makers to involve primary care populations in their recommendations.

Quantitative computed tomography measures of pectoralis muscle area and disease severity in chronic obstructive pulmonary disease. A cross-sectional study

RATIONALE

Muscle wasting in chronic obstructive pulmonary disease (COPD) is associated with a poor prognosis and is not readily assessed by measures of body mass index (BMI). BMI does not discriminate between relative proportions of adipose tissue and lean muscle and may be insensitive to early pathologic changes in body composition. Computed tomography (CT)-based assessments of the pectoralis muscles may provide insight into the clinical significance of skeletal muscles in smokers.

OBJECTIVES

We hypothesized that objective assessment of the pectoralis muscle area on chest CT scans provides information that is clinically relevant and independent of BMI.

METHODS

Data from the ECLIPSE (Evaluation of COPD Longitudinally to Identify Predictive Surrogate Endpoints) Study (n = 73) were used to assess the relationship between pectoralis muscle area and fat-free mass. We then used data in a subset (n = 966) of a larger cohort, the COPDGene (COPD Genetic Epidemiology) Study, to explore the relationship between pectoralis muscle area and COPD-related traits.

MEASUREMENTS AND MAIN RESULTS

We first investigated the correlation between pectoralis muscle area and fat-free mass, using data from a subset of participants in the ECLIPSE Study. We then further investigated pectoralis muscle area in COPDGene Study participants and found that higher pectoralis muscle area values were associated with greater height, male sex, and younger age. On subsequent clinical correlation, compared with BMI, pectoralis muscle area was more significantly associated with COPD-related traits, including spirometric measures, dyspnea, and 6-minute-walk distance (6MWD). For example, on average, each 10-cm(2) increase in pectoralis muscle area was associated with a 0.8-unit decrease in the BODE (Body mass index, Obstruction, Dyspnea, Exercise) index (95% confidence interval, -1.0 to -0.6; P < 0.001). Furthermore, statistically significant associations between pectoralis muscle area and COPD-related traits remained even after adjustment for BMI.

CONCLUSIONS

CT-derived pectoralis muscle area provides relevant indices of COPD morbidity that may be more predictive of important COPD-related traits than BMI. However, the relationship with clinically relevant outcomes such as hospitalization and death requires additional investigation. Pectoralis muscle area is a convenient measure that can be collected in the clinical setting in addition to BMI.

Impact of heterozygote CFTR mutations in COPD patients with chronic bronchitis

Background

Cigarette smoking causes Chronic Obstructive Pulmonary Disease (COPD), the 3rd leading cause of death in the U.S. CFTR ion transport dysfunction has been implicated in COPD pathogenesis, and is associated with chronic bronchitis. However, susceptibility to smoke induced lung injury is variable and the underlying genetic contributors remain unclear. We hypothesized that presence of CFTR mutation heterozygosity may alter susceptibility to cigarette smoke induced CFTR dysfunction. Consequently, COPD patients with chronic bronchitis may have a higher rate of CFTR mutations compared to the general population.

Methods

Primary human bronchial epithelial cells derived from F508del CFTR heterozygotes and mice with (CFTR+/-) and without (CFTR+/+) CFTR heterozygosity were exposed to whole cigarette smoke (WCS); CFTR-dependent ion transport was assessed by Ussing chamber electrophysiology and nasal potential difference measurements, respectively. Caucasians with COPD and chronic bronchitis, age 40 to 80 with FEV₁/FVC < 0.70 and FEV₁ < 60% predicted, were selected for genetic analysis from participants in the NIH COPD Clinical Research Network’s Azithromycin for Prevention of Exacerbations of COPD in comparison to 32,900 Caucasian women who underwent prenatal genetic testing. Genetic analysis involved an allele-specific genotyping of 89 CFTR mutations.

Results

Exposure to WCS caused a pronounced reduction in CFTR activity in both CFTR (+/+) cells and F508del CFTR (+/-) cells; however, neither the degree of decrement (44.7% wild-type vs. 53.5% F508del heterozygous, P = NS) nor the residual CFTR activity were altered by CFTR heterozygosity. Similarly, WCS caused a marked reduction in CFTR activity measured by NPD in both wild type and CFTR heterozygous mice, but the severity of decrement (91.1% wild type vs. 47.7% CF heterozygous, P = NS) and the residual activity were not significantly affected by CFTR genetic status. Five of 127 (3.9%) COPD patients with chronic bronchitis were heterozygous for CFTR mutations which was not significantly different from controls (4.5%) (P = NS).

Conclusions

The magnitude of WCS induced reductions in CFTR activity was not affected by the presence of CFTR mutation heterozygosity. CFTR mutations do not increase the risk of COPD with chronic bronchitis. CFTR dysfunction due to smoking is primarily an acquired phenomenon and is not affected by the presence of congenital CFTR mutations.

Plasma Fibrinogen as a Biomarker for Mortality and Hospitalized Exacerbations in People with COPD

BACKGROUND

In 2010 the COPD Foundation established the COPD Biomarkers Qualification Consortium (CBQC) as a partnership between the Foundation, the Food and Drug Administration (FDA), and the pharmaceutical industry to pool publicly-funded and industry data to develop innovative tools to facilitate the development and approval of new therapies for COPD. We present data from the initial project seeking regulatory qualification of fibrinogen as a biomarker for the stratification of COPD patients into clinical trials.

METHODS

This analysis pooled data from 4 publicly-funded studies and 1 industry study into a common database resulting in 6376 individuals with spirometric evidence of COPD. We used a threshold of 350 mg/dL to determine high vs. low fibrinogen, and determined the subsequent risk of hospitalizations from exacerbations and death using Cox proportional hazards models.

RESULTS

High fibrinogen levels at baseline were present in 2853 (44.7%) of individuals with COPD. High fibrinogen was associated with an increased risk of hospitalized COPD exacerbations within 12 months (hazard ratio [HR]: 1.64; 95% confidence interval [CI]: 1.39-1.93) among participants in the Atherosclerosis Risk in Communities Study (ARIC), the Cardiovascular Health Study (CHS), and the Evaluation of COPD Longitudinally to Identify Predictive Surrogate Endpoints (ECLIPSE) study. High fibrinogen was associated with an increased risk of death within 36 months (HR: 1.94; 95% CI: 1.62-2.31) among all participants.

CONCLUSIONS

Fibrinogen levels ≥ 350 mg/dL identify COPD individuals at an increased risk of exacerbations and death and could be a useful biomarker for enriching clinical trials in the COPD population.

Systemic soluble receptor for advanced glycation endproducts is a biomarker of emphysema and associated with AGER genetic variants in patients with chronic obstructive pulmonary disease

RATIONALE

Emphysema in chronic obstructive pulmonary disease (COPD) can be characterized by high-resolution chest computed tomography (HRCT); however, the repeated use of HRCT is limited because of concerns regarding radiation exposure and cost.

OBJECTIVES

To evaluate biomarkers associated with emphysema and COPD-related clinical characteristics, and to assess the relationships of soluble receptor for advanced glycation endproducts (sRAGE), a candidate systemic biomarker identified in this study, with single-nucleotide polymorphisms (SNPs) in the gene coding for RAGE (AGER locus) and with clinical characteristics.

METHODS

Circulating levels of 111 biomarkers were analyzed for association with clinical characteristics in 410 patients with COPD enrolled in the TESRA study. sRAGE was also measured in the ECLIPSE cohort in 1,847 patients with COPD, 298 smokers and 204 nonsmokers. The association between 21 SNPs in the AGER locus with sRAGE levels and clinical characteristics was also investigated.

MEASUREMENTS AND MAIN RESULTS

sRAGE was identified as a biomarker of diffusing capacity of carbon monoxide and lung density in the TESRA cohort. In the ECLIPSE cohort, lower sRAGE levels were associated with increased emphysema, increased Global Initiative for Chronic Obstructive Lung Disease stage, and COPD disease status. The associations with emphysema in both cohorts remained significant after covariate adjustment (P < 0.0001). One SNP in the AGER locus, rs2070600, was associated with circulating sRAGE levels both in TESRA (P = 0.0014) and ECLIPSE (7.07 × 10(-16)), which exceeded genome-wide significance threshold. Another SNP (rs2071288) was also associated with sRAGE levels (P = 0.01) and diffusing capacity of carbon monoxide (P = 0.01) in the TESRA study.

CONCLUSIONS

Lower circulating sRAGE levels are associated with emphysema severity and genetic polymorphisms in the AGER locus are associated with systemic sRAGE levels. Clinical trial registered with www.clinicaltrials.gov (NCT 00413205 and NCT 00292552).

Lessons from ECLIPSE: a review of COPD biomarkers

The Evaluation of COPD Longitudinally to Identify Predictive Surrogate End-points (ECLIPSE) study was a large 3-year observational controlled multicentre international study aimed at defining clinically relevant subtypes of chronic obstructive pulmonary disease (COPD) and identifying novel biomarkers and genetic factors. So far, the ECLIPSE study has produced more than 50 original publications and 75 communications to international meetings, many of which have significantly influenced our understanding of COPD. However, because there is not one paper reporting the biomarker results of the ECLIPSE study that may serve as a reference for practising clinicians, researchers and healthcare providers from academia, industry and government agencies interested in COPD, we decided to write a review summarising the main biomarker findings in ECLIPSE.

Nitric oxide synthase polymorphisms, gene expression and lung function in chronic obstructive pulmonary disease

Background

Due to the pleiotropic effects of nitric oxide (NO) within the lungs, it is likely that NO is a significant factor in the pathogenesis of chronic obstructive pulmonary disease (COPD). The aim of this study was to test for association between single nucleotide polymorphisms (SNPs) in three NO synthase (NOS) genes and lung function, as well as to examine gene expression and protein levels in relation to the genetic variation.

Methods

One SNP in each NOS gene (neuronal NOS (NOS1), inducible NOS (NOS2), and endothelial NOS (NOS3)) was genotyped in the Lung Health Study (LHS) and correlated with lung function. One SNP (rs1800779) was also analyzed for association with COPD and lung function in four COPD case–control populations. Lung tissue expression of NOS3 mRNA and protein was tested in individuals of known genotype for rs1800779. Immunohistochemistry of lung tissue was used to localize NOS3 expression.

Results

For the NOS3 rs1800779 SNP, the baseline forced expiratory volume in one second in the LHS was significantly higher in the combined AG + GG genotypic groups compared with the AA genotypic group. Gene expression and protein levels in lung tissue were significantly lower in subjects with the AG + GG genotypes than in AA subjects. NOS3 protein was expressed in the airway epithelium and subjects with the AA genotype demonstrated higher NOS3 expression compared with AG and GG individuals. However, we were not able to replicate the associations with COPD or lung function in the other COPD study groups.

Conclusions

Variants in the NOS genes were not associated with lung function or COPD status. However, the G allele of rs1800779 resulted in a decrease of NOS3 gene expression and protein levels and this has implications for the numerous disease states that have been associated with this polymorphism.

Pathophysiology and clinical implications of pulmonary arterial enlargement in COPD

Chronic obstructive pulmonary disease (COPD) is a complex condition defined by progressive airflow limitation in response to noxious stimuli, inflammation, and vascular changes. COPD exacerbations are critical events in the natural history of the disease, accounting for the majority of disease burden, cost, and mortality. Pulmonary vascular disease is an important risk factor for disease progression and exacerbation risk. Relative pulmonary artery enlargement on computed tomography scan, defined by a pulmonary artery to aortic (PA:A) ratio >1, has been evaluated as a marker of pulmonary vascular disease. The PA:A ratio can be measured reliably independent of electrocardiographic gating or the use of contrast, and in healthy patients a PA:A ratio >0.9 is considered to be abnormal. The PA:A ratio has been compared with invasive hemodynamic parameters, primarily mean pulmonary artery pressure in various disease conditions and is more strongly correlated with mean pulmonary artery pressure in obstructive as compared with interstitial lung disease. In patients without known cardiac or pulmonary disease, the PA:A ratio is predictive of mortality, while in COPD, an elevated PA:A ratio is correlated with increased exacerbation risk, outperforming other well established predictors of these events. Future studies should be aimed at determining the stability of the metric over time and evaluating the utility of the PA:A ratio in guiding specific therapies.

Analysis of the plasma proteome in COPD: Novel low abundance proteins reflect the severity of lung remodeling

The search for COPD biomarkers has largely employed a targeted approach that focuses on plasma proteins involved in the systemic inflammatory response and in lung injury and repair. This proof of concept study was designed to test the idea that an open, unbiased, in-depth proteomics approach could identify novel, low abundance plasma proteins i.e., ng/mL concentration, which could serve as potential biomarkers. Differentially expressed proteins were identified in a discovery group with severe COPD (FEV1 <45% predicted; n = 10). Subjects with normal lung function matched for age, sex, ethnicity and smoking history served as controls (n = 10). Pooled plasma from each group was exhaustively immunodepleted of abundant proteins, d separated by 1-D gel electrophoresis and extensively fractionated prior to LC-tandem mass spectroscopy (GeLC-MS). Thirty one differentially expressed proteins were identified in the discovery group including markers of lung defense against oxidant stress, alveolar macrophage activation, and lung tissue injury and repair. Four of the 31 proteins (i.e., GRP78, soluble CD163, IL1AP and MSPT9) were measured in a separate verification group of 80 subjects with varying COPD severity by immunoassay. All 4 were significantly altered in COPD and 2 (GRP78 and soluble CD163) correlated with both FEV1 and the extent of emphysema. In-depth, plasma proteomic analysis identified a group of novel, differentially expressed, low abundance proteins that reflect known pathogenic mechanisms and the severity of lung remodeling in COPD. These proteins may also prove useful as COPD biomarkers.

The role of desmosines as biomarkers for chronic obstructive pulmonary disease

Since chronic obstructive pulmonary disease (COPD) has a progressive and major impact on health management, many aspects of this disorder, including development of effective and reliable biomarkers to monitor disease progression, are under intensive investigation. A huge amount of data, accumulated over the years, have provided solid evidence that two pyridinium-ring-containing amino acid isoforms, desmosine and isodesmosine (usually referred to as desmosines), unique to mature elastin in humans, are representative of the elastin breakdown occurring in chronic destructive disorders, such as COPD. This paper is aimed at providing a critical review of the methodological steps that have marked the progress in the detection of desmosines in biological fluids in health and disease, as well as the progress in the authors knowledge of desmosines' role in the pathophysiology of COPD. The authors have tried to emphasize that the suitability of desmosine as a biomarker for COPD increased over the years, as the techniques developed for its detection became progressively more sophisticated and precise. The authors conclude that desmosines, although not yet definitely proven, have nevertheless all the requisites to become a critical COPD biomarker.

Pulmonary emphysema in cystic fibrosis detected by densitometry on chest multidetector computed tomography

Background

Histopathological studies on lung specimens from patients with cystic fibrosis (CF) and recent results from a mouse model indicate that emphysema may contribute to CF lung disease. However, little is known about the relevance of emphysema in patients with CF. In the present study, we used computationally generated density masks based on multidetector computed tomography (MDCT) of the chest for non-invasive characterization and quantification of emphysema in CF.

Methods

Volumetric MDCT scans were acquired in parallel to pulmonary function testing in 41 patients with CF (median age 20.1 years; range 7-66 years) and 21 non-CF controls (median age 30.4 years; range 4-68 years), and subjected to dedicated software. The lung was segmented, low attenuation volumes below a threshold of -950 Hounsfield units were assigned to emphysema volume (EV), and the emphysema index was computed (EI). Results were correlated with forced expiratory volume in 1 s percent predicted (FEV1%), residual volume (RV), and RV/total lung capacity (RV/TLC).

Results

We show that EV was increased in CF (457±530 ml) compared to non-CF controls (78±90 ml) (P<0.01). EI was also increased in CF (7.7±7.5%) compared to the control group (1.2±1.4%) (P<0.05). EI correlated inversely with FEV1% (r_s=-0.66), and directly with RV (r_s=0.69) and RV/TLC (r_s=0.47) in patients with CF (P<0.007), but not in non-CF controls. Emphysema in CF was detected from early adolescence (~13 years) and increased with age (r_s=0.67, P<0.001).

Conclusions

Our results indicate that early onset emphysema detected by densitometry on chest MDCT is a characteristic pathology that contributes to airflow limitation and may serve as a novel endpoint for monitoring lung disease in CF.

Semi-automated scoring of pulmonary emphysema from X-ray CT: trainee reproducibility and accuracy

OBJECTIVE

We developed a semi-automated tool to quantify emphysema from thoracic X-ray multi-detector (64-slice) computed tomography (CT) for training purposes and multi-reader studies.

MATERIALS AND METHODS

Thoracic X-ray CT was acquired in 93 ex-smokers, who were evaluated by six trainees with little or no expertise (trainees) and a single experienced thoracic radiologist (expert). A graphic user interface (GUI) was developed for emphysema quantification based on the percentile of lung where a score of 0=no abnormalities, 1=1-25%, 2=26-50%, 3=51-75% and 4=76-100% for each lung side/slice. Trainees blinded to subject characteristics scored randomized images twice; accuracy was determined by comparison to expert scores, density histogram 15th percentile (HU 15), relative area at -950 HU (RA(950)), low attenuation clusters at -950 HU (LAC(950)), -856 HU (LAC(856)) and the diffusing capacity for carbon monoxide (DL(CO%pred)). Intra- and inter-observer reproducibility was evaluated using coefficients-of-variation (COV), intra-class (ICC) and Pearson correlations.

RESULTS

Trainee-expert correlations were significant (r=0.85-0.97, p<0.0001) and a significant trainee bias (0.15 ± 0.22) was observed. Emphysema score was correlated with RA(950) (r=0.88, p<0.0001), HU 15 (r=-0.77, p<0.0001), LAC(950) (r=0.76, p<0.0001), LAC(856) (r=0.74, p=0.0001) and DLCO%pred (r=-0.71, p<0.0001). Intra-observer reproducibility (COV=4-27%; ICC=0.75-0.94) was moderate to high for trainees; intra- and inter-observer COV were negatively and non-linearly correlated with emphysema score.

CONCLUSION

We developed a GUI for rapid and interactive emphysema scoring that allows for comparison of multiple readers with clinical and radiological standards.

Factors associated with change in exacerbation frequency in COPD

BACKGROUND

Patients with chronic obstructive pulmonary disease (COPD) can be categorized as having frequent (FE) or infrequent (IE) exacerbations depending on whether they respectively experience two or more, or one or zero exacerbations per year. Although most patients do not change category from year to year, some will, and the factors associated with this behaviour have not been examined.

METHODS

1832 patients completing two year follow-up in the Evaluation of COPD Longitudinally to Identify Predictive Surrogate End-points (ECLIPSE) study were examined at baseline and then yearly. Exacerbations were defined by health care utilisation. Patient characteristics compared between those patients who did or did not change exacerbation category from year 1 to year 2.

FINDINGS

Between years 1 and 2, 221 patients (17%) changed from IE to FE and 210 patients (39%) from FE to IE. More severe disease was associated with changing from IE to FE and less severe disease from FE to IE. Over the preceding year, small falls in FEV1 and 6-minute walking distance were associated with changing from IE to FE, and small falls in platelet count associated with changing from FE to IE.

CONCLUSION

No parameter clearly predicts an imminent change in exacerbation frequency category.

TRIAL REGISTRATION

SCO104960, clinicaltrials.gov identifier NCT00292552.

Chronic obstructive pulmonary disease and bronchiectasis

PURPOSE OF REVIEW

Chronic obstructive pulmonary disease (COPD) and bronchiectasis are two different but related diseases that occur separately, but can coexist. In this review, we will examine the recent research regarding patients with COPD who have coexisting bronchiectasis.

RECENT FINDINGS

Recent research has focused on defining distinct COPD phenotypes with the ultimate goal of changing the outcomes using tailored therapies. A frequent exacerbator phenotype has been identified. COPD patients with Pseudomonas aeruginosa are a phenotype with worse outcomes. Patients with coexisting COPD and bronchiectasis may represent a unique phenotype.

SUMMARY

Patients with coexisting COPD and bronchiectasis could represent a unique phenotype with more severe disease, worse outcomes, more isolation of potentially pathogenic microorganisms, and more frequent exacerbations, with the potential for targeted therapies.

Assessment of potential drug interactions by characterization of human drug metabolism pathways using non-invasive bile sampling

AIM

Characterization of the biliary disposition of GSK1325756, using a non-invasive bile sampling technique and spectrometric analyses, to inform the major routes of metabolic elimination and to enable an assessment of victim drug interaction risk.

METHOD

Sixteen healthy, elderly subjects underwent non-invasive bile capture using a peroral string device (Entero-Test(®)) prior to and following a single oral dose of GSK1325756 (100 mg). The device was swallowed by each subject and once the weighted string was judged to have reached the duodenum, gallbladder contraction was stimulated in order to release bile. The string was then retrieved via the mouth and bile samples were analyzed for drug-related material using spectrometric and spectroscopic techniques following solvent extraction.

RESULTS

Nuclear magnetic resonance spectroscopy (NMR) indicated that the O-glucuronide metabolite was the major metabolite of GSK1325756, representing approximately 80% of drug-related material in bile. As bile is the major clearance route for GSK1325756 (only 4% of the administered dose was excreted in human urine), this result indicates that uridine 5'-diphospho-glucuronosyltransferases (UGTs) are the major drug metabolizing enzymes responsible for drug clearance. The relatively minor contribution made by oxidative routes reduces the concern of CYP-mediated victim drug interactions.

CONCLUSION

The results from this study demonstrate the utility of deploying the Entero-Test® in early human studies to provide information on the biliary disposition of drugs and their metabolites. This technique can be readily applied in early clinical development studies to provide information on the risk of interactions for drugs that are metabolized and eliminated in bile.

Analysis of chloroformate-derivatised amino acids, dipeptides and polyamines by LC-MS/MS

A liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed which, with sample preparation using a commercially available kit, allows rapid quantitation of 39 chloroformate-derivatised amino acids (AAs), polyamines (PAs) and dipeptides (DPs) in complex biological matrices. Lower limits of quantitation (LOQ) were 20-150nM for putrescine, spermine, spermidine, cadaverine, agmatine, and below 5μM for all analytes. Responses were linear for all analytes between 0.5 and 50μM. Quantitative measurements of all 39 metabolites were achieved within a 15min runtime. The method was evaluated with a Pseudomonas aeruginosa cell extract study (n=24) and a larger human urine study (n=308). Batch effects were observed in the urine study and an investigation of instrument and sample stability showed a wave-like pattern in the MS responses. Both the run order and inter-batch variation were successfully corrected by normalising to pooled urine quality control data. Thus, this method should be suitable for diverse biological matrices and for large as well as small sample sets.

Comorbidity, systemic inflammation and outcomes in the ECLIPSE cohort

Comorbidities, are common in COPD, have been associated with poor outcomes and are thought to relate to systemic inflammation. To investigate comorbidities in relation to systemic inflammation and outcomes we recorded comorbidities in a well characterized cohort (ECLIPSE study) for 2164 clinically stable COPD subjects, 337 smokers and 245 non-smokers with normal lung function. COPD patients had a higher prevalence of osteoporosis, anxiety/panic attacks, heart trouble, heart attack, and heart failure, than smokers or nonsmokers. Heart failure (Hazard Ratio [HR] 1.9, 95% Confidence Interval [CI] 1.3-2.9), ischemic heart disease (HR 1.5, 95% CI 1.1-2.0), heart disease (HR 1.5, 95% CI 1.2-2.0), and diabetes (HR 1.7, 95% CI 1.2-2.4) had increased odds of mortality when coexistent with COPD. Multiple comorbidities had accumulative effect on mortality. COPD and cardiovascular disease was associated with poorer quality of life, higher MRC dyspnea scores, reduced 6MWD, higher BODE index scores. Osteoporosis, hypertension and diabetes were associated with higher MRC dyspnea scores and reduced 6MWD. Higher blood concentrations of fibrinogen, IL-6 and IL-8 levels occurred in those with heart disease. Comorbidity is associated with poor clinical outcomes in COPD. The comorbidities of heart disease, hypertension and diabetes are associated with increased systemic inflammation.