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RATIONALE: The course of lung function, respiratory symptoms, and functional status over time in people who smoke cigarettes is still incompletely understood. The COPDGene (Genetic Epidemiology of Chronic Obstructive Pulmonary Disease [COPD]) study provides a unique cohort to examine these trajectories, and now 10-year follow-up data are available. OBJECTIVES: This study aims to provide insight into the progression of spirometric parameters, respiratory symptoms, and functional capacity over 10 years in current and former cigarette smokers. METHODS: We analyzed available longitudinal data for COPDGene participants who did not change smoking status over three visits spanning approximately 10 years of follow-up. Change in postbronchodilator forced expiratory volume in 1 second (FEV(1)), St. George’s Respiratory Questionnaire (SGRQ), and 6-minute walk distance (6MWD) from Phase 1 to Phase 3 were examined using linear mixed models. Terms were included in the models to estimate mean progression separately for current and former cigarette smokers. Models were stratified by baseline Global Initiative for Chronic Obstructive Lung Disease (GOLD) spirometry stages as well as by new 2019 COPDGene classification. RESULTS: The mean age at enrollment of the 9,103 participants in this analysis was 59.8 years (SD = 9.2 yr); 46.4% were women, and 32.6% were African American. In all GOLD COPD groups, including participants with normal spirometry, and all groups categorized by 2019 COPDGene classification, FEV(1) decreased, SGRQ increased (indicating higher symptom burden), and 6MWD decreased over the 10-year follow-up period. Current smokers exhibited a greater mean loss of FEV(1) over the study period than former smokers for all groups except those with preserved ratio impaired spirometry. For both SGRQ and 6MWD, rates of progression tended to be similar for former and current smokers except for 6MWD in the highest severity groups, in which former smokers had greater progression. However, this could be impacted by some current smokers with faster progression who had quit smoking and were dropped from analyses. CONCLUSIONS: Progression in FEV(1), SGRQ, and 6MWD overall appears to be slow, and the change over time in groups traditionally characterized as not having disease closely mirrors that of the groups with COPD at all GOLD stages. Current cigarette smokers had greater loss of FEV(1) than former smokers, whereas SGRQ and 6MWD changes were more similar between current and former cigarette smokers.

Rationale: The ability of peripheral blood biomarkers to assess COPD risk and progression is unknown. Genetics and gene expression may capture important aspects of COPD-related biology that predict...

RATIONALE: Multiple studies have demonstrated an increased risk of chronic obstructive pulmonary disease (COPD) in heterozygous carriers of the AAT (alpha-1 antitrypsin) Z allele. However, it is not known if MZ subjects with COPD are phenotypically different from noncarriers (MM genotype) with COPD. OBJECTIVES: To assess if MZ subjects with COPD have different clinical features compared with MM subjects with COPD. METHODS: Genotypes of SERPINA1 were ascertained by using whole-genome sequencing data in three independent studies. We compared outcomes between MM subjects with COPD and MZ subjects with COPD in each study and combined the results in a meta-analysis. We performed longitudinal and survival analyses to compare outcomes in MM and MZ subjects with COPD over time. MEASUREMENTS AND MAIN RESULTS: We included 290 MZ subjects with COPD and 6,184 MM subjects with COPD across the three studies. MZ subjects had a lower FEV(1)% predicted and greater quantitative emphysema on chest computed tomography scans compared with MM subjects. In a meta-analysis, the FEV(1) was 3.9% lower (95% confidence interval [CI], −6.55% to −1.26%) and emphysema (the percentage of lung attenuation areas

Chronic obstructive pulmonary disease (COPD) is a common and progressive disease that is influenced by both genetic and environmental factors. For many years, knowledge of the genetic basis of COPD was limited to Mendelian syndromes, such as alpha-1 antitrypsin deficiency and cutis laxa, caused by rare genetic variants. Over the past decade, the proliferation of genome-wide association studies, the accessibility of whole-genome sequencing, and the development of novel methods for analyzing genetic variation data have led to a substantial increase in the understanding of genetic variants that play a role in COPD susceptibility and COPD-related phenotypes. COPDGene (Genetic Epidemiology of COPD), a multicenter, longitudinal study of over 10,000 current and former cigarette smokers, has been pivotal to these breakthroughs in understanding the genetic basis of COPD. To date, over 20 genetic loci have been convincingly associated with COPD affection status, with additional loci demonstrating association with COPD-related phenotypes such as emphysema, chronic bronchitis, and hypoxemia. In this review, we discuss the contributions of the COPDGene study to the discovery of these genetic associations as well as the ongoing genetic investigations of COPD subtypes, protein biomarkers, and post–genome-wide association study analysis.

Genome-wide association studies (GWAS) have identified multiple associations with emphysema apicobasal distribution (EABD), but the biological functions of these variants are unknown. To characterize the functions of EABD-associated variants, we integrated GWAS results with 1) expression quantitative trait loci (eQTL) from the Genotype Tissue Expression (GTEx) project and subjects in the COPDGene (Genetic Epidemiology of COPD) study and 2) cell type epigenomic marks from the Roadmap Epigenomics project. On the basis of these analyses, we selected a variant near ACVR1B (activin A receptor type 1B) for functional validation. SNPs from 168 loci with P values less than 5 × 10(−5) in the largest GWAS meta-analysis of EABD were analyzed. Eighty-four loci overlapped eQTL, with 12 of these loci showing greater than 80% likelihood of harboring a single, shared GWAS and eQTL causal variant. Seventeen cell types were enriched for overlap between EABD loci and Roadmap Epigenomics marks (permutation P

Rationale: Increasing awareness of the prevalence and significance of Preserved Ratio Impaired Spirometry (PRISm), alternatively known as restrictive or Global Initiative for Chronic Obstructive Lu...

There is an unmet need for blood biomarkers in diagnosis and prognosis of chronic obstructive pulmonary disease (COPD). The search for these biomarkers has been revolutionized by high-throughput sequencing techniques and multiplex platforms that can measure thousands of gene transcripts, proteins, or metabolites. We review COPDGene (Genetic Epidemiology of COPD) project publications that include DNA methylation, transcriptomic, proteomic, and metabolomic blood biomarkers and discuss their impact on COPD. Key contributions from COPDGene include identification of DNA methylation effects from smoking and genetic variation, new transcriptomic signatures in the blood, identification of protein biomarkers associated with severity and progression (e.g., sRAGE [soluble receptor for advanced glycosylation end products], inflammatory cytokines IL-6 and IL-8), and identification of small molecules (ceramides and sphingomyelin) that may be pathogenic. COPDGene studies have revealed that some of the COPD genome-wide association study polymorphisms are strongly associated with blood biomarkers (e.g., rs2070600 in AGER is a pQTL [protein quantitative trait locus] for sRAGE), underscoring the importance of combining omics results. Investigators have developed molecular networks identifying lower CD4(+) resting memory cells associated with COPD. Genes, proteins, and metabolite networks are particularly important because the explanatory value of any single molecule is small (1–10%) compared with panels of multiple markers. COPDGene has been a useful resource in the identification and validation of multiple biomarkers for COPD. These biomarkers, either combined in multiple biomarker panels or integrated with other omics data types, may lead to novel diagnostic and prognostic tests for COPD phenotypes and may be relevant for assessing novel therapies.

Genomic regions identified by genome-wide association studies explain only a small fraction of heritability for chronic obstructive pulmonary disease (COPD). Alpha-1 antitrypsin deficiency shows that rare coding variants of large effect also influence COPD susceptibility. We hypothesized that exome sequencing in families identified through a proband with severe, early-onset COPD would identify additional rare genetic determinants of large effect.To identify rare genetic determinants of severe COPD.We applied filtering approaches to identify potential causal variants for COPD in whole exomes from 347 subjects in 49 extended pedigrees from the Boston Early-Onset COPD Study. We assessed the power of this approach under different levels of genetic heterogeneity using simulations. We tested genes identified in these families using gene-based association tests in exomes of 204 cases with severe COPD and 195 resistant smokers from the COPDGene study. In addition, we examined previously described loci associated with COPD using these datasets.We identified 69 genes with predicted deleterious nonsynonymous, stop, or splice variants that segregated with severe COPD in at least two pedigrees. Four genes (DNAH8, ALCAM, RARS, and GBF1) also demonstrated an increase in rare nonsynonymous, stop, and/or splice mutations in cases compared with resistant smokers from the COPDGene study; however, these results were not statistically significant. We demonstrate the limitations of the power of this approach under genetic heterogeneity through simulation.Rare deleterious coding variants may increase risk for COPD, but multiple genes likely contribute to COPD susceptibility.

Rationale: Sequence variation, methylation differences, and transcriptional changes in desmoplakin (DSP) have been observed in patients with idiopathic pulmonary fibrosis (IPF).Objectives: To identify novel variants in DSP associated with IPF and to characterize the relationship of these IPF sequence variants with DSP gene expression in human lung.Methods: A chromosome 6 locus (7,370,061–7,606,946) was sequenced in 230 subjects with IPF and 228 control subjects. Validation genotyping of disease-associated variants was conducted in 936 subjects with IPF and 936 control subjects. DSP gene expression was measured in lung tissue from 334 subjects with IPF and 201 control subjects.Measurements and Main Results: We identified 23 sequence variants in the chromosome 6 locus associated with IPF. Genotyping of selected variants in our validation cohort revealed that noncoding intron 1 variant rs2744371 (odds ratio = 0.77, 95% confidence interval [CI] = 0.66–0.91, P = 0.002) is protective for IPF, and a previously d...

Spirometric Volumes and Breathlessness Across Levels of Airflow Limitation : The COPDGene Study.

Asthma is associated with chronic airflow obstruction. Our goal was to assess the association of computed tomographic measures of airway wall volume and lumen volume with the FEV1 and chronic airflow obstruction in smokers with childhood-onset asthma.We analyzed clinical, lung function, and volumetric computed tomographic airway volume data from 7,266 smokers, including 590 with childhood-onset asthma. Small wall volume and small lumen volume of segmental airways were defined as measures 1 SD below the mean. We assessed the association between small wall volume, small lumen volume, FEV1, and chronic airflow obstruction (post-bronchodilator FEV1/FVC ratio0.7) using linear and logistic models.Compared with subjects without childhood-onset asthma, those with childhood-onset asthma had smaller wall volume and lumen volume (P0.0001) of segmental airways. Among subjects with childhood-onset asthma, those with the smallest wall volume and lumen volume had the lowest FEV1 and greatest odds of chronic airflow obstruction. A similar tendency was seen in those without childhood-onset asthma. When comparing these two groups, both small wall volume and small lumen volume were more strongly associated with FEV1 and chronic airflow obstruction among subjects with childhood-asthma in multivariate models.In smokers with childhood-onset asthma, smaller airways are associated with reduced lung function and chronic airflow obstruction. Clinical trial registered with www.clinicaltrials.gov (NCT00608764).

Chronic obstructive pulmonary disease (COPD) is a complex set of conditions with multiple risk factors, disease mechanisms, and clinical manifestations. These characteristics make primary prevention of COPD challenging. Semantic issues related to prevalent and incident disease (e.g., the use of specific cut points on a continuous range) should not derail development of primary prevention initiatives. Potential targets for COPD prevention occur along the spectrum of disease development. Understanding risk factors early in life, whether specific to COPD or not, allows for study of interventions to optimize lung function at birth and to prolong the lung function plateau, potentially reducing the development of COPD. It is necessary to identify noninvasive ways to screen for early COPD in those at risk before progression to clinically significant disease. Identification of specific COPD subgroups, such as individuals with chronic bronchitis, those with α1-antitrypsin deficiency, or early radiographic changes with normal spirometry, may offer specific opportunities for primary prevention. A better understanding of why COPD progresses despite smoking cessation is needed. Future research initiatives should also focus on identifying the underlying mechanisms and relevant interventions for nonsmokers with COPD, a currently poorly studied group. Ultimately, preventing the development of COPD will serve to reduce the tremendous burden of this chronic disease worldwide.

Angiographic investigation suggests that pulmonary vascular remodeling in smokers is characterized by distal pruning of the blood vessels.Using volumetric computed tomography scans of the chest we sought to quantitatively evaluate this process and assess its clinical associations.Pulmonary vessels were automatically identified, segmented, and measured. Total blood vessel volume (TBV) and the aggregate vessel volume for vessels less than 5 mm(2) (BV5) were calculated for all lobes. The lobe-specific BV5 measures were normalized to the TBV of that lobe and the nonvascular tissue volume (BV5/T(issue)V) to calculate lobe-specific BV5/TBV and BV5/T(issue)V ratios. Densitometric measures of emphysema were obtained using a Hounsfield unit threshold of -950 (%LAA-950). Measures of chronic obstructive pulmonary disease severity included single breath measures of diffusing capacity of carbon monoxide, oxygen saturation, the 6-minute-walk distance, St George's Respiratory Questionnaire total score (SGRQ), and the body mass index, airflow obstruction, dyspnea, and exercise capacity (BODE) index.The %LAA-950 was inversely related to all calculated vascular ratios. In multivariate models including age, sex, and %LAA-950, lobe-specific measurements of BV5/TBV were directly related to resting oxygen saturation and inversely associated with both the SGRQ and BODE scores. In similar multivariate adjustment lobe-specific BV5/T(issue)V ratios were inversely related to resting oxygen saturation, diffusing capacity of carbon monoxide, 6-minute-walk distance, and directly related to the SGRQ and BODE.Smoking-related chronic obstructive pulmonary disease is characterized by distal pruning of the small blood vessels (5 mm(2)) and loss of tissue in excess of the vasculature. The magnitude of these changes predicts the clinical severity of disease.

Automated analysis of computed tomographic (CT) lung images for epidemiologic and genetic association studies is increasingly common, but little is known about the utility of visual versus semiautomated emphysema and airway assessments for genetic association studies.Assess the relative utility of visual versus semiautomated emphysema and airway assessments for genetic association studies.A standardized inspection protocol was used to visually assess chest CT images for 1,540 non-Hispanic white subjects within the COPDGene Study for the presence and severity of radiographic features representing airway wall thickness and emphysema. A genome-wide association study (GWAS) was performed, and two sets of candidate single-nucleotide polymorphisms with a higher prior likelihood of association were specified a priori for separate analysis. For each visual CT examination feature, a corresponding semiautomated CT feature(s) was identified for comparison in the same subjects.GWAS for visual features of chest CT scans identified a genome-wide significant association with visual emphysema at the 15q25 locus (P = 6.3eStandardized visual assessments of emphysema and airway disease are significantly associated with genetic loci previously associated with chronic obstructive pulmonary disease susceptibility or semiautomated CT examination phenotypes in GWAS. Visual CT measures of emphysema and airways disease offer independent information for genetic association studies in relation to standard semiautomated measures.

Despite the increasing recognition of asthma-chronic obstructive pulmonary disease overlap syndrome (ACOS) as a clinical entity, it remains poorly characterized due to a lack of agreement on its definition and diagnostic criteria.The aim of this study was to use spirometry and computed tomography (CT) to help better define ACOS as well as to classify subjects with ACOS based on Global Initiative for Chronic Obstructive Lung Disease (GOLD) letter grade.We analyzed 10,192 subjects enrolled in the COPDGene Study. Subjects were non-Hispanic white or African American current or former smokers aged 45-80 years with at least a 10-pack-year smoking history. Subjects were categorized as having either ACOS with a bronchodilator response or chronic obstructive pulmonary disease with emphysema on the basis of spirometry, high-resolution CT, and a history of asthma or hay fever.Subjects with ACOS were younger (60.6 vs. 65.9 years old; P 0.0001), more likely to be African American (26.8% vs. 14.4%; P 0.0001), had a higher body mass index (29.6 vs. 25.1 kg/m(2); P 0.0001), and were more likely to be current smokers (50.9% vs. 20.7%; P 0.0001). The majority of subjects with ACOS were categorized as GOLD grade B. Despite less severe spirometry and CT findings in subjects with ACOS, there was no significant difference in severe or frequent exacerbations.Bronchodilator responsiveness and degree of emphysema can help define ACOS. When defined on the basis of bronchodilator responsiveness and degree of emphysema, patients with ACOS represent a unique and high-risk group with distinct clinical features.

Background: The small conducting airways are the major site of airflow obstruction in COPD and may precede emphysema development. We hypothesized a novel CT biomarker of small airways disease predicts FEV1 decline. Methods: We analyzed 1,508 current and former smokers from COPDGene with linear regression to assess predictors of change in FEV1 (ml/year) over 5 years. Separate models for non-obstructed and obstructed subjects were generated using baseline clinical and physiologic predictors in addition to two novel CT metrics created by Parametric Response Mapping (PRM), a technique pairing inspiratory and expiratory CT images to define emphysema (PRMemph) and functional small airways disease (PRMfSAD), a measure of non-emphysematous air trapping. Results: Mean (SD) rate of FEV1 decline in ml/year for GOLD 0-4 was as follows: 41.8 (47.7), 53.8 (57.1), 45.6 (61.1), 31.6 (43.6), and 5.1 (35.8) respectively (trend test for grades 1-4, p

Rationale: Chronic obstructive pulmonary disease (COPD) susceptibility is in part related to genetic variants. Most genetic studies have been focused on genome-wide common variants without a specific focus on coding variants, but common and rare coding variants may also affect COPD susceptibility. Objectives: To identify coding variants associated with COPD. Methods: We tested nonsynonymous, splice, and stop variants derived from the Illumina HumanExome array for association with COPD in five study populations enriched for COPD. We evaluated single variants with a minor allele frequency greater than 0.5% using logistic regression. Results were combined using a fixed effects meta-analysis. We replicated novel single-variant associations in three additional COPD cohorts. Measurements and Main Results: We included 6,004 control subjects and 6,161 COPD cases across five cohorts for analysis. Our top result was rs16969968 (P = 1.7 X 10(-14)) in CHRNA5, a locus previously associated with COPD susceptibility and nicotine dependence. Additional top results were found in AGER, MMP3, and SERPINA1. A nonsynonymous variant, rs181206, ina27 (P = 4.7 X 10(-6)) was just below the level of exome-wide significance but attained exome-wick significance (P = 5.7 X 10(-8)) when combined with results from other cohorts. Gene expression datasets revealed an association of rs181206 and the surrounding locus with expression of multiple genes; several were differentially expressed in COPD lung tissue, including TUFM. Conclusions: In an exome array analysis of COPD, we identified nonsynonymous variants at previously described loci and a novel exome-wide significant variant in IL27. This variant is at a locus previously described in genome-wide associations with diabetes, inflammatory bowel disease, and obesity and appears to affect genes potentially related to COPD pathogenesis.

Rationale: The role of 3-hydroxy-3-methylglutaryl-coenzyme A reductase inhibitors (statins) in the development or progression of interstitial lung disease (ILD) is controversial.Objectives: To evaluate the association between statin use and ILD.Methods: We used regression analyses to evaluate the association between statin use and interstitial lung abnormalities (ILA) in a large cohort of smokers from COPDGene. Next, we evaluated the effect of statin pretreatment on bleomycin-induced fibrosis in mice and explored the mechanism behind these observations in vitro.Measurements and Main Results: In COPDGene, 38% of subjects with ILA were taking statins compared with 27% of subjects without ILA. Statin use was positively associated in ILA (odds ratio, 1.60; 95% confidence interval, 1.03–2.50; P = 0.04) after adjustment for covariates including a history of high cholesterol or coronary artery disease. This association was modified by the hydrophilicity of statin and the age of the subject. Next, we demonstrate ...

Am J Respir Crit Care Med. 2012 Dec 15;186(12):1238-1247. Epub 2012 Nov 9 Rationale: A genome-wide association study (GWAS) for circulating chronic obstructive pulmonary disease (COPD) biomarkers could identify genetic determinants of biomarker levels and COPD susceptibility. Objectives: To identify genetic variants of circulating protein biomarkers and novel genetic determinants of COPD. Methods: GWAS was performed for two pneumoproteins, Clara cell secretory protein (CC16) and surfactant protein D (SP-D), and five systemic inflammatory markers (C-reactive protein, fibrinogen, IL-6, IL-8, and tumor necrosis factor-α) in 1,951 subjects with COPD. For genome-wide significant single nucleotide polymorphisms (SNPs) (P < 1 × 10(-8)), association with COPD susceptibility was tested in 2,939 cases with COPD and 1,380 smoking control subjects. The association of candidate SNPs with mRNA expression in induced sputum was also elucidated. Measurements and Main Results: Genome-wide significant susceptibility loci affecting biomarker levels were found only for the two pneumoproteins. Two discrete loci affecting CC16, one region near the CC16 coding gene (SCGB1A1) on chromosome 11 and another locus approximately 25 Mb away from SCGB1A1, were identified, whereas multiple SNPs on chromosomes 6 and 16, in addition to SNPs near SFTPD, had genome-wide significant associations with SP-D levels. Several SNPs affecting circulating CC16 levels were significantly associated with sputum mRNA expression of SCGB1A1 (P = 0.009-0.03). Several SNPs highly associated with CC16 or SP-D levels were nominally associated with COPD in a collaborative GWAS (P = 0.001-0.049), although these COPD associations were not replicated in two additional cohorts. Conclusions: Distant genetic loci and biomarker-coding genes affect circulating levels of COPD-related pneumoproteins. A subset of these protein quantitative trait loci may influence their gene expression in the lung and/or COPD susceptibility. Clinical trial registered with www.clinicaltrials.gov (NCT 00292552). PMID:23144326[PubMed - as supplied by publisher] Rationale: A genome-wide association study (GWAS) for circulating chronic obstructive pulmonary disease (COPD) biomarkers could identify genetic determinants of biomarker levels and COPD susceptibility. Objectives: To identify genetic variants of circulating protein biomarkers and novel genetic determinants of COPD. Methods: GWAS was performed for two pneumoproteins, Clara cell secretory protein (CC16) and surfactant protein D (SP-D), and five systemic inflammatory markers (C-reactive protein, fibrinogen, IL-6, IL-8, and tumor necrosis factor-α) in 1,951 subjects with COPD. For genome-wide significant single nucleotide polymorphisms (SNPs) (P

Rationale: A significant proportion of smokers have lung function impairment characterized by a reduced FEV1 with a preserved FEV1/FVC ratio. These smokers are a poorly characterized group due to their systematic exclusion from chronic obstructive pulmonary disease (COPD) studies. Objectives: To characterize the clinical, functional, and radiographic features of Global Initiative for Chronic Obstructive Lung Disease (GOLD)-Unclassified (FEV1/FVC ≥ 0.7 and FEV1 < 80% predicted) and lower limits of normal (LLN)-unclassified (FEV1/FVC ≥ LLN and FEV1 < LLN) subjects compared to smokers with normal lung function and subjects with COPD. Methods: Data from the first 2,500 subjects enrolled in the COPDGene study were analyzed. All subjects had 10 or more pack-years of smoking and were between the ages of 45 and 80 years. Multivariate regression models were constructed to determine the clinical and radiological variables associated with GOLD-Unclassified (GOLD-U) and LLN-Unclassified status. Separate multivariate regressions were performed in the subgroups of subjects with complete radiologic measurement variables available. Measurements and Main Results: GOLD-U smokers account for 9% of smokers in COPDGene and have increased body mass index (BMI), a disproportionately reduced total lung capacity, and a higher proportion of nonwhite subjects and subjects with diabetes. GOLD-U subjects exhibit increased airway wall thickness compared to smoking control subjects and decreased gas trapping and bronchodilator responsiveness compared to subjects with COPD. When LLN criteria were used to define the “unclassified” group, African American subjects were no longer overrepresented. Both GOLD-U and LLN-Unclassified subjects demonstrated a wide range of lung function impairment, BMI, and percentage of total lung emphysema. Conclusions: Subjects with reduced FEV1 and a preserved FEV1/FVC ratio are a heterogeneous group with significant symptoms and functional limitation who likely have a variety of underlying etiologies beyond increased BMI. Clinical trial registered with www.clinicaltrials.gov (NCT000608764).

Mycobacterium abscessus is a rapidly growing environmental mycobacterium that can cause severe skin, soft tissue, and lung infections. M. abscessus grows inside macrophages, and these cells release a vast number of proinflammatory cytokines in response to infections. The metalloporphyrin, MnTE-2-PyP, is a broad antioxidant that reduces inflammatory cell signaling. Macrophage-like THP-1 cells were infected with M. abscessus in the presence or absence of MnTE-2-PyP. MnTE-2-PyP significantly decreased, in a dose-dependent manner, the number of M. abscessus organisms recovered from infected THP-1 cells 4 and 8 days after infection. Furthermore, when combined with clarithromycin, MnTE-2-PyP additively reduced the number of cells associated with M. abscessus. A mechanism of bacterial growth inhibition by MnTE-2-PyP was then elucidated. It was found that MnTE-2-PyP promoted the survival of infected THP-1 cells and increased fusion of M. abscessus-containing phagosomes with lysosomes.

Chronic obstructive pulmonary disease (COPD) is a common condition, and one difficult to manage. Available treatments, other than smoking cessation, are only minimally effective, and the knowledge basis for clinical decision making is limited. To identify areas in which further clinical research may lead to significant improvements in the care of patients with COPD, the National Heart, Lung, and Blood Institute convened a Working Group, entitled "Clinical Research in COPD: Needs and Opportunities," on March 21-22, 2002. This group of experts identified important questions in the field and made the following recommendations: (1) establish a multicenter Clinical Research Network to perform multiple, short-term clinical trials of treatments in patients with moderate-to-severe COPD; (2) create a system for the standardized collection, processing, and distribution of lung tissue specimens and associated clinical and laboratory data; (3) develop standards for the classification and staging of COPD; (4) characterize the development and progression of COPD using measures and biomarkers that relate to current concepts of pathogenesis; and (5) evaluate indications for long-term oxygen therapy for patients with COPD.

Superoxide anion and other oxygen-free radicals have been implicated in the pathogenesis of bronchopulmonary dysplasia. We tested the hypothesis that a catalytic antioxidant metalloporphyrin AEOL 10113 can protect against hyperoxia-induced lung injury using a fetal baboon model of bronchopulmonary dysplasia. Fetal baboons were delivered by hysterotomy at 140 days of gestation (term = 185 days) and given 100% oxygen for 10 days. Morphometric analysis of alveolar structure showed that fetal baboons on 100% oxygen alone had increased parenchymal mast cells and eosinophils, increased alveolar tissue volume and septal thickness, and decreased alveolar surface area compared with animals given oxygen as needed. Treatment with AEOL 10113 (continuous intravenous infusion) during 100% oxygen exposure partially reversed these oxygen-induced changes. Hyperoxia increased the number of neuroendocrine cells in the peripheral lung, which was preceded by increased levels of urine bombesin-like peptide at 48 hours of age. AEOL 10113 inhibited the hyperoxia-induced increases in urine bombesin-like peptide and numbers of neuroendocrine cells. An increasing trend in oxygenation index over time was observed in the 100% oxygen group but not the mimetic-treated group. These results suggest that AEOL 10113 might reduce the risk of pulmonary oxygen toxicity in prematurely born infants.

Oxidative stress plays an important role in the development of fibrotic responses in the lung. However, it is not clear whether inhibiting oxidative stress with antioxidants can attenuate fibrotic processes in the lung. The objective of these studies was to test whether the catalytic antioxidant porphyrin manganese (III) tetrakis (4-benzoic acid) porphyrin (MnTBAP) could protect mice against bleomycin-induced lung fibrosis. A 10 mg/kg intraperitoneal dose of MnTBAP was established as safe and had a serum and lung half-life of 9.5 h in mice. Based on this data, four groups of mice were given one dose of bleomycin (3.2 U/kg, intratracheal) or saline and MnTBAP (5 mg/kg, intraperitoneal) or saline twice daily for 14 d. Lung fibrosis was assessed by measuring (1) lung hydroxyproline content as an index of collagen accumulation, (2) airway dysfunction by whole body plethysmography, and (3) histopathology. Bleomycin produced a 20% loss in body weight that was only 10% in the bleomycin/MnTBAP group. Bleomycin produced a twofold increase in hydroxyproline content that was decreased 23% by MnTBAP. Bleomycin produced a twofold increase in airway dysfunction that was also attenuated 30% by MnTBAP. Histopathologic analysis of the lungs of mice treated with bleomycin demonstrated a severe fibrotic response that was attenuated 28% by MnTBAP. Future studies on the oxidant mechanisms that MnTBAP is affecting in this bleomycin model of lung fibrosis may shed light on potential new therapeutic approaches for treating interstitial lung diseases.

The antioxidant enzymes copper/zinc (Cu-Zn) and manganese (Mn) superoxide dismutase (SOD) have been implicated in protection of the lungs from oxidant damage. Mn SOD in particular may be related to acquired tolerance in cells following chronic ozone exposure. In order to study these protective and adaptive phenomena in oxidant injury, the cellular location and relative abundance of Mn SOD and Cu-Zn SOD were examined in the lungs of Fischer 344 rats following exposure to 0.0 and 1.0 ppm ozone for up to 3 mo using immunolabeling and morphometric techniques. Cu-Zn SOD labeling was found to be markedly reduced following ozone exposure in epithelial cells within airways and parenchyma. In contrast, a significant increase was noted in Mn SOD labeling in the centriacinar regions of exposed lungs for both alveolar macrophages and epithelial type II cells. Mn SOD labeling per epithelial type II cell was significantly increased in alveoli 0-400 microm beyond the bronchiole-alveolar duct junction (BADJ), while type II cell Mn SOD labeling was similar to control values with greater distance down the alveolar duct. No induction of Mn SOD was noted in type I epithelial cells, fibroblasts, or Clara cells. Thus, alterations in Cu-Zn and Mn SOD are both site and cell specific in the lungs. The differential increase in Mn SOD in type II cells of the proximal alveolar duct may reflect the ability of these cells to acquire tolerance and to resist further injury to repeated ozone exposure.

Extracellular superoxide dismutase (EC-SOD) is the major extracellular antioxidant enzyme. We have determined the primary structure of mouse EC-SOD by characterization of complementary DNA (cDNA) clones and by amino-acid sequence analysis of purified protein. cDNA sequence analysis indicates that mouse EC-SOD is synthesized as a 251-amino-acid precursor protein with a predicted molecular weight of 27,400 D. Amino-terminal micro sequence analysis of purified mature mouse lung EC-SOD demonstrated the sequence to begin with SSFDLADRLDPV-. These results indicate that EC-SOD as initially synthesized contains a 24-amino-acid precursor peptide, and that the mature protein is 227 amino acids in length. Computer algorithms that predict the most likely site of cotranslational signal peptidase cleavage suggest that processing will occur between amino acids 18 and 19 or 20 and 21, which implies that EC-SOD may be initially synthesized as a pre-pro-protein. Like human EC-SOD, mature mouse EC-SOD is glycosylated. The full-length mouse EC-SOD cDNA is 1,834 base pairs long and is 82% (79% for protein) identical to rat EC-SOD, but only 60% (60% for protein) identical to human EC-SOD. The mouse EC-SOD gene locus (Sod3) was mapped by interspecific backcross haplotype analysis as being 0.9 +/- 0.9 centimorgans distal to the Qdpr locus on mouse Chromosome 5, a position suggesting that the human homologue of EC-SOD will map close to the human QDPR locus (4p15.3). Of nine tissues examined by Northern blot analysis, those of the kidney and lung are by far the major tissues that express EC-SOD messenger RNA. Using in situ hybridization in the mouse lung, we demonstrate EC-SOD gene expression to be highly localized to alveolar Type II epithelial cells. These data suggest that alveolar Type II cells play a central role in mediating EC-SOD antioxidant function in the lung.

The extracellular form of superoxide dismutase (EC-SOD), SOD3, is contained in the human lung in relatively high amounts when compared to other organs. It has not been previously shown whether or not EC-SOD is synthesized and secreted by specific lung cells. We examined the expression of EC-SOD mRNA in human lung cells by in situ hybridization using a digoxigenin-labeled EC-SOD cRNA probe. Strong signals of EC-SOD synthesis were found in the epithelium of all airways. Secretory and basal cells, but not ciliated cells, were labeled for EC-SOD mRNA. Expression of EC-SOD mRNA was found in endothelial cells lining both arteries and veins. Many cells in the alveolar septum exhibited strong expression of EC-SOD mRNA. In addition, epithelial cells lining the outer wall of intrapulmonary airways and vessels were heavily labeled for EC-SOD mRNA. The lung parenchymal epithelial cells containing EC-SOD mRNA were identified as alveolar type II cells by colocalization with surfactant protein-A. Human alveolar macrophages were found to contain a substantial amount of EC-SOD mRNA expression. Alveolar type I epithelial cells and capillary endothelial cells did not display detectable signals of EC-SOD mRNA. Smooth muscle cells in muscular arteries were not labeled by the EC-SOD mRNA probe. These results show that airway epithelial cells and alveolar type II cells are the major cell types that synthesize fibroblasts EC-SOD in the human lung. EC-SOD has been shown by immunocytochemistry to be associated with the extracellular matrix around airway epithelium and in the walls of intrapulmonary arterioles. The site of EC-SOD localization, therefore, is closely related to the site of its synthesis.

Because alveolar macrophages generate and release reactive oxygen metabolites but also contain antioxidative enzymes, they have the potential of either damaging or protecting tissues. We investigated the relative role of the hydrogen peroxide (H2O2)-scavenging antioxidative enzymes in H2O2 disposal and cell protection using freshly isolated (5 h ex vivo) and overnight (24 h ex vivo) cultured human alveolar macrophages. Cell protection was assessed on the basis of maintenance of cellular high-energy phosphates, leakage of intact nucleotides into the extracellular medium, and appearance of the nucleotide catabolic products xanthine, hypoxanthine, and uric acid. To investigate the relative importance of catalase and the glutathione redox cycle, the experiments were conducted in cells pretreated with amino-triazole (ATZ) to inactivate catalase or with 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU) to inactivate glutathione reductase. Catalase, glutathione peroxidase, and glutathione reductase activities did not change significantly during overnight culture of the cells. Both freshly isolated and cultured cells consumed exogenous H2O2 mainly by the catalase-dependent pathway. When the cells were exposed to H2O2 (100 microM), catalase and the glutathione redox cycle equally participated in maintaining cellular high-energy nucleotides. However, when cultured cells were exposed to formylated peptide (FMLP) (10(-7) M), the glutathione redox cycle was responsible for the maintenance of high-energy nucleotides. Furthermore, in both exposures, the glutathione redox cycle was more important in maintaining cell membrane integrity and preventing nucleotide leakage from the cells. Immunocytochemical labeling showed that catalase was primarily localized in the peroxisomal compartment of these cells.(ABSTRACT TRUNCATED AT 250 WORDS)