Chronic obstructive pulmonary disease. 1: Susceptibility factors for COPD the genotype-environment interaction

EPHX1 and GSTP1 polymorphisms are associated with COPD risk: a systematic review and meta-analysis

Background: Chronic obstructive pulmonary disease (COPD) affects approximately 400 million people worldwide and is associated with high mortality and morbidity. The effect of EPHX1 and GSTP1 gene polymorphisms on COPD risk has not been fully characterized. Objective: To investigate the association of EPHX1 and GSTP1 gene polymorphisms with COPD risk. Methods: A systematic search was conducted on 9 databases to identify studies published in English and Chinese. The analysis was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses reporting guidelines (PRISMA). The pooled OR and 95% CI were calculated to evaluate the association of EPHX1 and GSTP1 gene polymorphisms with COPD risk. The I² test, Q test, Egger's test, and Begg's test were conducted to determine the level of heterogeneity and publication bias of the included studies. Results: In total, 857 articles were retrieved, among which 59 met the inclusion criteria. The EPHX1 rs1051740 polymorphism (homozygote, heterozygote, dominant, recessives, and allele model) was significantly associated with high risk of COPD risk. Subgroup analysis revealed that the EPHX1 rs1051740 polymorphism was significantly associated with COPD risk among Asians (homozygote, heterozygote, dominant, and allele model) and Caucasians (homozygote, dominant, recessives, and allele model). The EPHX1 rs2234922 polymorphism (heterozygote, dominant, and allele model) was significantly associated with a low risk of COPD. Subgroup analysis showed that the EPHX1 rs2234922 polymorphism (heterozygote, dominant, and allele model) was significantly associated with COPD risk among Asians. The GSTP1 rs1695 polymorphism (homozygote and recessives model) was significantly associated with COPD risk. Subgroup analysis showed that the GSTP1 rs1695 polymorphism (homozygote and recessives model) was significantly associated with COPD risk among Caucasians. The GSTP1 rs1138272 polymorphism (heterozygote and dominant model) was significantly associated with COPD risk. Subgroup analysis suggested that the GSTP1 rs1138272 polymorphism (heterozygote, dominant, and allele model) was significantly associated with COPD risk among Caucasians. Conclusion: The C allele in EPHX1 rs1051740 among Asians and the CC genotype among Caucasians may be risk factors for COPD. However, the GA genotype in EPHX1 rs2234922 may be a protective factor against COPD in Asians. The GG genotype in GSTP1 rs1695 and the TC genotype in GSTP1 rs1138272 may be risk factors for COPD, especially among Caucasians.

HLA-C and KIR permutations influence chronic obstructive pulmonary disease risk

A role for hereditary influences in the susceptibility for chronic obstructive pulmonary disease (COPD) is widely recognized. Cytotoxic lymphocytes are implicated in COPD pathogenesis, and functions of these leukocytes are modulated by interactions between their killer cell Ig-like receptors (KIR) and human leukocyte antigen–Class I (HLA–Class I) molecules on target cells. We hypothesized HLA–Class I and KIR inheritance affect risks for COPD. HLA–Class I alleles and KIR genotypes were defined by candidate gene analyses in multiple cohorts of patients with COPD (total n = 392) and control smokers with normal spirometry (total n = 342). Compared with controls, patients with COPD had overrepresentations of HLA-C*07 and activating KIR2DS1, with underrepresentations of HLA-C*12. Particular HLA-KIR permutations were synergistic; e.g., the presence of HLA-C*07 + KIR2DS1 + HLA-C12^null versus HLAC*07^null + KIR2DS1^null + HLA-C12 was associated with COPD, especially among HLA-C1 allotype homozygotes. Cytotoxicity of COPD lymphocytes was more enhanced by KIR stimulation than those of controls and was correlated with lung function. These data show HLA-C and KIR polymorphisms strongly influence COPD susceptibility and highlight the importance of lymphocyte-mediated cytotoxicity in COPD pathogenesis. Findings here also indicate that HLA-KIR typing could stratify at-risk patients and raise possibilities that HLA-KIR axis modulation may have therapeutic potential.

Asthma-COPD overlap: current understanding and the utility of experimental models

Pathological features of both asthma and COPD coexist in some patients and this is termed asthma-COPD overlap (ACO). ACO is heterogeneous and patients exhibit various combinations of asthma and COPD features, making it difficult to characterise the underlying pathogenic mechanisms. There are no controlled studies that define effective therapies for ACO, which arises from the lack of international consensus on the definition and diagnostic criteria for ACO, as well as scant in vitro and in vivo data. There remain unmet needs for experimental models of ACO that accurately recapitulate the hallmark features of ACO in patients. The development and interrogation of such models will identify underlying disease-causing mechanisms, as well as enabling the identification of novel therapeutic targets and providing a platform for assessing new ACO therapies. Here, we review the current understanding of the clinical features of ACO and highlight the approaches that are best suited for developing representative experimental models of ACO.

Understanding the pathogenesis of asthma-COPD overlap is critical for improving therapeutic approaches. We present current knowledge on asthma-COPD overlap and the requirements for developing an optimal animal model of disease.https://bit.ly/3lsjyvm

Test Gene-Environment Interactions for Multiple Traits in Sequencing Association Studies

MOTIVATION

The risk of many complex diseases is determined by an interplay of genetic and environmental factors. The examination of gene-environment interactions (G×Es) for multiple traits can yield valuable insights about the etiology of the disease and increase power in detecting disease-associated genes. However, the methods for testing G×Es for multiple traits are very limited.

METHOD

We developed novel approaches to test G×Es for multiple traits in sequencing association studies. We first perform a transformation of multiple traits by using either principal component analysis or standardization analysis. Then, we detect the effects of G×Es using novel proposed tests: testing the effect of an optimally weighted combination of G×Es (TOW-GE) and/or variable weight TOW-GE (VW-TOW-GE). Finally, we employ Fisher's combination test to combine the p values.

RESULTS

Extensive simulation studies show that the type I error rates of the proposed methods are well controlled. Compared to the interaction sequence kernel association test (ISKAT), TOW-GE is more powerful when there are only rare risk and protective variants; VW-TOW-GE is more powerful when there are both rare and common variants. Both TOW-GE and VW-TOW-GE are robust to directions of effects of causal G×Es. Application to the COPDGene Study demonstrates that our proposed methods are very effective.

CONCLUSIONS

Our proposed methods are useful tools in the identification of G×Es for multiple traits. The proposed methods can be used not only to identify G×Es for common variants, but also for rare variants. Therefore, they can be employed in identifying G×Es in both genome-wide association studies and next-generation sequencing data analyses.

Testing gene-environment interactions for rare and/or common variants in sequencing association studies

The risk of many complex diseases is determined by a complex interplay of genetic and environmental factors. Advanced next generation sequencing technology makes identification of gene-environment (GE) interactions for both common and rare variants possible. However, most existing methods focus on testing the main effects of common and/or rare genetic variants. There are limited methods developed to test the effects of GE interactions for rare variants only or rare and common variants simultaneously. In this study, we develop novel approaches to test the effects of GE interactions of rare and/or common risk, and/or protective variants in sequencing association studies. We propose two approaches: 1) testing the effects of an optimally weighted combination of GE interactions for rare variants (TOW-GE); 2) testing the effects of a weighted combination of GE interactions for both rare and common variants (variable weight TOW-GE, VW-TOW-GE). Extensive simulation studies based on the Genetic Analysis Workshop 17 data show that the type I error rates of the proposed methods are well controlled. Compared to the existing interaction sequence kernel association test (ISKAT), TOW-GE is more powerful when there are GE interactions' effects for rare risk and/or protective variants; VW-TOW-GE is more powerful when there are GE interactions' effects for both rare and common risk and protective variants. Both TOW-GE and VW-TOW-GE are robust to the directions of effects of causal GE interactions. We demonstrate the applications of TOW-GE and VW-TOW-GE using an imputed data from the COPDGene Study.

Surfactant protein A expression and distribution in human lung samples from smokers with or without chronic obstructive pulmonary disease in China

Cigarette smoking is considered the main risk factor for chronic obstructive pulmonary disease (COPD), although the mechanism remains unknown. surfactant protein A (SP-A) is thought to protect the lung from smoking-induced damage, but related studies performed in China are scarce. The aim of the study is to assess alterations of SP-A expression and distribution in lung samples from Chinese smokers with or without COPD.This cross-sectional study assessed 45 men in Wuhan Tongji Hospital after lobectomy for lung cancer in June 2010 to September 2010. Peripheral lung specimens were collected from control nonsmokers without airflow obstruction (nonsmoking group, n = 15), smokers without airflow obstruction (smoking group, n = 15), and patients with COPD (COPD group, n = 15). SP-A expression levels in lung tissue samples and its distribution in lung cells, type II pneumocytes (PNII), and alveolar macrophages (MACR) were determined by immunoblotting and immunohistochemistry.SP-A levels were significantly decreased in the COPD group (1.00 ± 0.25) compared with the smoking (2.31 ± 0.64) and nonsmoking (8.03 ± 2.80) groups; the smoking group also showed significantly reduced levels compared with the nonsmoking group (P < .05). PNII expressing SP-A were less abundant in the COPD group (39.3% ± 7.1%) compared with the smoking group (76.2% ± 29.8%), whereas SP-A MACR were more abundant (92.4% ± 7.1% vs 68.5% ± 20.2%) (all P < .05). Among the 30 smokers, forced expiratory volume in one second (% predicted) was positively correlated with SP-A levels (r = 0.739) and the rate of SP-A+ PNII (r = 0.811), and negatively correlated with the rate of SP-A+ MACR (r = -0.758) (all P < .05).Changes in SP-A expression and distribution in lung tissues may be involved in COPD pathogenesis in smokers.

ACE gene polymorphism is associated with COPD and COPD with pulmonary hypertension: a meta-analysis

Purpose

Angiotensin-converting enzyme (ACE) gene I/D polymorphism has been studied in relation to the susceptibility to COPD and COPD with pulmonary hypertension (PH) with inconclusive results. We performed the first comprehensive meta-analysis to evaluate accurately the association between the ACE gene polymorphism and the risk of COPD.

Methods

Data were analyzed using odds ratios (ORs) and the corresponding 95% CIs to measure the strength of the models. Subgroup analyses were conducted by ethnicity and complication which referred to PH.

Results

In total, 15 studies (2,635 participants) were included in our study, of which four studies (288 participants) were for PH subgroup. The overall analysis results indicated that the ACE gene polymorphism was not associated with COPD susceptibility in all gene models. However, the ethnic subgroup analysis results indicated that ACE gene polymorphism was associated with Asians’ susceptibility to COPD (DD+DI vs II, OR=1.47, P=0.019, 95% CI: 1.07–2.02). Further, the overall results of the present study detected no statistical significance between ACE gene polymorphism and the risk of COPD with PH, but the homozygote variant (DD) increased the risk of PH in Asian COPD patients (DD vs ID+II, OR=2.05, P=0.05, 95% CI: 1.00–4.19).

Conclusion

The current study suggests that ACE polymorphism, particularly the homozygote variant (DD), might contribute to the risk of COPD and COPD with PH among Asians. Further studies with larger sample size and more ethnicities are expected to be conducted in the future to validate the results.

One-year Prevalence, Comorbidities, and Cost of Hospitalizations for Alpha-1 Antitrypsin Deficiency among Patients with Chronic Obstructive Pulmonary Disease in the United States

Objectives: Little is known about severe chronic obstructive pulmonary disease (COPD) exacerbations among patients with Alpha-1 Antitrypsin Deficiency (AATD). We assessed inpatients with AATD and COPD among a sample of COPD inpatients to ascertain demographic, clinical and economic differences in the course of disease and treatment. Methods: Using data from the 2009 Nationwide Inpatient Sample (NIS), we identified COPD (ICD-9-CM: 491.xx, 492.xx, or 496.xx) patients with AATD (273.4). We compared patient demographics and healthcare outcomes (eg, length of stay, inpatient death, type and number of procedures, and cost of care) between COPD patients with and without alpha-1 antitrypsin deficiency. Frequencies and percentages for patient demographics were compared using bivariate statistics (eg, chi-square test). Recognizing the non-parametric nature of length of stay and cost, we calculated median values and interquartile ranges for these variables for each group of patients. Finally, the risk of inpatient death was estimated using logistic regression. Results: Of 840 242 patients with COPD (10.8% of the NIS sample population), 0.08% (684) had a primary or secondary diagnosis code for AATD. COPD+AATD were younger (56 vs 70, p<0.0001) and as a result, less likely to be covered by Medicare (44% vs 62%, p<0.0001). AATD patients were also more likely to have comorbid non-alcoholic liver disease (7% vs 2%, p<0.0001), depression (17% vs 13%, p=0.0328), and pulmonary circulation disorders (7% vs 4%, p=0.0299). Patients with AATD had a 14% longer length of stay (IRR = 1.14, 95% CI 1.07, 1.21) and a mean cost of $1487 (p=0.0251) more than COPD inpatients without AATD. Conclusions: AATD is associated with increased mean length of stay and cost, as well as higher frequency of comorbid non-alcoholic liver disease, depression, and pulmonary circulation disorders. Future research should assess other differences between AATD and the general COPD population such as natural history of disease, treatment responsiveness and disease progression.

Energy landscape of a GSTP1 polymorph linked with cytological function decay in response to chemical stressors

Gene polymorphisms lead to varied structure and functional properties. A single nucleotide polymorphism (SNP) i.e. Ile105Val (rs1695) in glutathione S-transferase P1 (GSTP1) gene influences cytological toxicity and modulates the risk to occupational diseases. Apart from this, cancer, neuropathy, NOx, SOx and ozone mediated respiratory function decline including lung inflammation, asthma, allergy etc., have been reported in people with this missense mutation. Here, the functional properties of rs1695 polymorph are revisited through a computational approach. Changes incurred by GSTP1 antioxidant protein as a result of alteration in its sequence, have been studied through docking followed by Poisson-Boltzmann electrostatic equation interpretation, grid and coulombic energy profile mapping for protein polymorphs with DelPhi. Molecular docking simulation of variant and wild type (WT) protein was carried out with eight FDA approved compounds that target GSTP1 for treatment of various diseases. This was to observe binding pattern variation upon mutation induction. Grid, reaction field and coulombic energy calculation of WT and mutated polymorph, complexed with and without these moieties was then attempted. Alteration in conformation and energy was observed in apo- and holo- form of GSTP1 and their ligand-bound complexes as a result of this mutation. This study is a demo of appraising gene-environment interaction based deleteriousness through molecular docking and dynamics simulation approach.

The Keap1-Nrf2-ARE Pathway As a Potential Preventive and Therapeutic Target: An Update

The Keap1-Nrf2-ARE ((Kelch-like ECH-Associating protein 1) nuclear factor erythroid 2 related factor 2-antioxidant response element) pathway is one of the most important defense mechanisms against oxidative and/or electrophilic stresses, and it is closely associated with inflammatory diseases, including cancer, neurodegenerative diseases, cardiovascular diseases, and aging. In recent years, progress has been made in strategies aimed at modulating the Keap1-Nrf2-ARE pathway. The Nrf2 activator DMF (Dimethylfumarates) has been approved by the FDA as a new first-line oral drug to treat patients with relapsing forms of multiple sclerosis, while a phase 3 study of another promising candidate, CDDO-Me, was terminated for safety reasons. Directly inhibiting Keap1-Nrf2 protein-protein interactions as a novel Nrf2-modulating strategy has many advantages over using electrophilic Nrf2 activators. The development of Keap1-Nrf2 protein-protein interaction inhibitors has become a topic of intense research, and potent inhibitors of this target have been identified. In addition, inhibiting Nrf2 activity has attracted an increasing amount of attention because it may provide an alternative cancer therapy. This review summarizes the molecular mechanisms and biological functions of the Keap1-Nrf2-ARE system. The main focus of this review is on recent progress in studies of agents that target the Keap1-Nrf2-ARE pathway and the therapeutic applications of such agents.

In vitro modeling of COPD inflammation and limitation of p38 inhibitor - SB203580

Background

Systemic inflammation and steroid resistance are the hallmarks of COPD. We examined the impact of p38 inhibitor (SB203580) in in vitro assays of systemic inflammation using pulmonary cells and patients’ sera.

Objective and methods

Data from 66 COPD patients and 15 age-/sex-matched healthy controls were compared. Interleukin-10 (IL-10), tumor necrosis factor-α (TNF-α), and CCL5 were measured in serum samples and culture media from peripheral blood mononuclear cells. The impact of sera on IL-10 and CCL5 expression in alveolar macrophage cell line (MH-S) was examined. The in vitro effects of SB203580 on lipopolysaccharide-induced inflammation were investigated.

Results

Peripheral blood mononuclear cells from Global initiative for chronic Obstructive Lung Disease (GOLD) D patients produced more CCL5 and TNF-α, and less IL-10 compared to GOLD A–C patients. SB203580 treatment suppressed CCL5 and TNF-α and stimulated IL-10 production; however, the effect of SB203580 on IL-10 was lower in the COPD group. Culture of MH-S cells with COPD serum showed a significant increase in CCL5 and a significant decrease in IL-10 compared to healthy serum. This effect was not suppressed with SB203580 treatment.

Conclusion

COPD serum has a potent proinflammatory effect on pulmonary cells. Inhibition of p38 phoshorylation had a limited effect in restoring impaired lymphocyte function and suppressing inflammation induced by COPD serum, implying important p38-independent inflammatory mechanisms in COPD.

Association of IREB2 Gene rs2568494 Polymorphism with Risk of Chronic Obstructive Pulmonary Disease: A Meta-Analysis

Background

It is reported that the iron-responsive element-binding protein 2 (IREB2) gene rs2568494 polymorphism might be associated with COPD risk. The purpose of this meta-analysis was to collect all eligible studies to review the association between IREB2 gene rs2568494 polymorphism and susceptibility to COPD.

Material/Methods

We carried out a comprehensive document search of electronic databases of PubMed, MEDLIN, Web of Science, and included 4 eligible studies that examined the association between IREB2 rs2568494 polymorphism and COPD susceptibility. We performed a meta-analysis of these studies based on IREB2 rs2568494 genotypes.

Results

After meta-analysis with fixed or random effects, no significant associations were found under the heterozygote model (GG/GA; OR=0.908, 95%CI: 0.790–1.043; P=0.172), homozygote model (GG/AA; OR=0.880, 95%CI: 0.497–1.557; P=0.661), dominant model (GG/AA+GA; OR=0.941, 95%CI: 0.748–1.182; P=0.599), or allelic model (G/A; OR=0.953, 95%CI: 0.770–1.179; P=0.655). However, we found a significant correlation under the recessive model (AA/GA+GG; OR=1.384, 95%CI: 1.092–1.755; P=0.007).

Conclusions

The current results revealed that there was significant association between IREB2 gene rs2568494 polymorphism with susceptibility to COPD; the presence of allelic A might a genetic factor conferring susceptibility to COPD.

Genetic polymorphisms of matrix metalloproteinases and protein levels in chronic obstructive pulmonary disease in a Mexican population

AIM

To evaluate association of single nucleotide polymorphisms (SNPs) in the MMP1, MMP2, MMP9 and MMP12 genes and serum MMP-2 and MMP-9 levels in smoking chronic obstructive pulmonary disease (COPD) patients.

MATERIALS & METHODS

Genotyping using real-time PCR in 330 smokers with COPD (COPD), 658 smokers without COPD (SNC) and 150 nonsmokers (NCNS), the analysis of samples used was χ(2) test. Using ELISA, the proteins were evaluated. Multiple comparisons were made by ANOVA.

RESULTS

rs243864 (OR: 7.44; 95% CI: 3.62-15.26) and rs11646643 (OR: 1.58; 95% CI: 1.07-2.34) of the MMP-2 gene and rs3918253 (OR: 1.72; 95% CI: 1.08-2.71) of the MMP-9 gene, were associated with the risk of COPD. Serum MMP-2 level in the COPD group was lower compared with SNC (p < 0.05). Serum MMP-9 level was elevated in the COPD group compared with SNC (p < 0.05).

CONCLUSION

Polymorphisms in MMP2 and MMP9 but not in MMP1 and MMP12 are associated with the risk of COPD in the Mexican mestizo population.

Associations of ABHD2 genetic variations with risks for chronic obstructive pulmonary disease in a Chinese Han population

The human α/β hydrolase domain-containing protein 2 gene (ABHD2) plays a critical role in pulmonary emphysema, a major subset of the clinical entity known as chronic obstructive pulmonary disease (COPD). Here, we evaluated genetic variation in the ABHD2 gene in a Chinese Han population of 286 COPD patients and 326 control subjects. The rs12442260 CT/CC genotype was associated with COPD (P < 0.001) under a dominant model. In the former-smoker group, the rs12442260 TT genotype was associated with a decreased risk of developing COPD after adjusting for age, gender and pack-years (P = 0.012). Rs12442260 was also associated with pre-FEV1 (the predicted bronchodilator forced expiratory volume in the first second) in controls (P = 0.027), but with FEV1/ forced vital capacity (FVC) ratios only in COPD patients (P = 0.012) under a dominant model. Results from the current study suggest that ABHD2 gene polymorphisms contribute to COPD susceptibility in the Chinese Han population.

Increased risk of radiographic emphysema in HIV is associated with elevated soluble CD14 and nadir CD4

BACKGROUND

The association between HIV and emphysema remains incompletely understood. We sought to determine whether HIV is an independent risk factor for emphysema severity and whether markers of HIV severity and systemic biomarkers of inflammation (IL-6), altered coagulation (D-dimer), and immune activation (soluble CD14) are associated with emphysema.

METHODS

We performed a cross-sectional analysis of 114 participants with HIV infection and 89 participants without HIV infection in the Examinations of HIV-Associated Lung Emphysema (EXHALE) study. Participants underwent chest CT imaging with blinded semiquantitative interpretation of emphysema severity, distribution, and type. We generated multivariable logistic regression models to determine the risk of HIV for radiographic emphysema, defined as > 10% lung involvement. Similar analyses examined associations of plasma biomarkers, HIV RNA, and recent and nadir CD4 cell counts with emphysema among participants with HIV infection.

RESULTS

Participants with HIV infection had greater radiographic emphysema severity with increased lower lung zone and diffuse involvement. HIV was associated with significantly increased risk for > 10% emphysema in analyses adjusted for cigarette smoking pack-years (OR, 2.24; 95% CI, 1.12-4.48). In multivariable analyses restricted to participants with HIV infection, nadir CD4 < 200 cells/μL (OR, 2.98; 95% CI, 1.14-7.81), and high soluble CD14 level (upper 25th percentile) (OR, 2.55; 95% CI, 1.04-6.22) were associated with increased risk of > 10% emphysema. IL-6 and D-dimer were not associated with emphysema in HIV.

CONCLUSIONS

HIV is an independent risk factor for radiographic emphysema. Emphysema severity was significantly greater among participants with HIV infection. Among those with HIV, nadir CD4 < 200 cells/μL and elevated soluble CD14 level were associated with emphysema, highlighting potential mechanisms linking HIV with emphysema.

Association between β2-Adrenergic Receptor-16Arg/Gly Gene Polymorphism and Chronic Obstructive Pulmonary Disease Risk:Systematic Review and Meta-Analysis

BACKGROUND

The association between β2-adrenergic receptor (ADRB2) -16Arg/Gly polymorphism (rs1042713) and chronic obstructive pulmonary disease (COPD) risk has been investigated in many published studies. However, the results were inconclusive. A meta-analysis was performed to make a more precise estimation of the relationship.

METHODS

The PubMed, EMBASE, ISI web of science, the Cochrane Database of Systematic Reviews, and Chinese databases (CNKI, Wanfang Data, CBM, VIP) were searched for published literature. Odds ratios (OR) with 95% confidence interval (CI) were used to assess the strength of association.

RESULTS

Eleven studies, comprising 1,128 COPD patients and 1,182 controls, were included in the meta-analysis. Overall, there was no significant association between the ADRB2-16Arg/Gly polymorphism and COPD risk in general population. In the stratification analysis by potential confounding variables, significant associations were observed between the ADRB2-16Arg/Gly polymorphism and COPD risk among smoking Asians under the dominant genetic model and allele model (Arg vs. Gly) (dominant model: OR = 1.45, 95% CI = 1.04-2.01, P = 0.311 for heterogeneity, z = 2.22, P = 0.026 for OR; allele model: OR = 1.27, 95% CI = 1.03-1.57, P = 0.209 for heterogeneity, z = 2.20, P = 0.028 for OR), but not in other subgroups.

CONCLUSION

This meta-analysis suggested that the ADRB2-16Arg/Gly polymorphism might be a potential risk factor for the development of COPD in smoking Asian populations, but not in European descendents, and tobacco smoking probably increased the genetic susceptibility. More studies with larger sample sizes are needed to validate the results.

Expression of aquaporins in bronchial tissue and lung parenchyma of patients with chronic obstructive pulmonary disease

Background

Aquaporins AQP1 and AQP5 are highly expressed in the lung. Recent studies have shown that the expression of these proteins may be mechanistically involved in the airway inflammation and in the pathogenesis of chronic obstructive pulmonary disease (COPD). The aim of this study was to investigate the expression of AQP1 and AQP5 in the bronchial tissue and the lung parenchyma of patients with COPD and COPD-resistant smokers.

Methods

Using a case–control design, we selected a group of 15 subjects with COPD and 15 resistant smokers (smokers without COPD) as a control, all of whom were undergoing lung resection surgery due to a lung neoplasm. We studied the expression of AQP1 and AQP5 in the bronchial tissue and the lung parenchyma by means of immunohistochemistry and reverse-transcription real-time polymerase chain reaction. Tissue expression of AQP1 and AQP5 was semi-quantitatively assessed in terms of intensity and expression by immunohistochemistry using a 4-point scale ranging from 0 (none) to 3 (maximum).

Results

There were no significant differences in gene expression between COPD patients and resistant smokers both in the bronchial tissue and in the lung parenchyma. However, AQP1 gene expression was 2.41-fold higher in the parenchyma of smokers with COPD compared to controls, whereas the AQP5 gene showed the opposite pattern, with a 7.75-fold higher expression in the bronchus of smokers with COPD compared with controls. AQP1 and AQP5 proteins were preferentially expressed in endothelial cells, showing a higher intensity for AQP1 (66.7% of cases with an intensity of 3, and 93.3% of subjects with an extension of 3 among patients with COPD). Subtle interstitial disease was associated with type II pneumocyte hyperplasia and an increased expression of AQP1.

Conclusions

This study provides pilot observations on the differences in AQP1 and AQP5 expression between COPD patients and COPD-resistant smokers. Our findings suggest a potential role for AQP1 in the pathogenesis of COPD.

Is TNF-α gene polymorphism related to pulmonary functions and prognosis as determined by FEV1, BMI, COPD exacerbation and hospitalization in patients with smoking-related COPD in a Turkish population?

INTRODUCTION

Some conflicting results have been published about the relationship between TNF-α-308 gene polymorphism and chronic obstructive pulmonary disease (COPD). The aim of this study was to determine whether TNF-α-308 gene polymorphism was associated with smoking-related COPD and whether it was associated with pulmonary function parameters (PFTs), body mass index (BMI), and prognosis.

METHODS

We studied the frequencies of TNF-α-308 gene polymorphism in 90 male subjects (60 subjects with COPD and 30 healthy smokers) in a Caucasian population.

RESULTS

There was no significant difference in the frequency of G/G and G/A gene polymorphisms in the COPD group compared with control subjects (p>0.05). We compared COPD patients as G/A gene polymorphism and G/G gene polymorphism; the PFTs and BMI before and after one year were not statistically significant (p>0.05). Also, the exacerbation and hospitalization data of COPD patients were not significant between these groups.

CONCLUSION

In conclusion, there was no difference between smoking-related COPD and the control group according to TNF α-308 gene polymorphism in a Caucasian population. In addition, it was shown that important determinants of prognosis of COPD such as FEV1, BMI, COPD exacerbation and hospitalization were not associated with TNF-α-308 gene polymorphism.

Trimethoprim-sulfamethoxazole treatment does not reverse obstructive pulmonary changes in pneumocystis-colonized nonhuman primates with SHIV infection

BACKGROUND

Despite antiretroviral therapy and trimethoprim-sulfamethoxazole (TMP-SMX) prophylaxis, Pneumocystis pneumonia remains an important serious opportunistic infection in HIV-infected persons. Pneumocystis (Pc) colonization in HIV-infected individuals and in HIV-uninfected smokers is associated with chronic obstructive pulmonary disease (COPD). We previously developed a nonhuman primate model of HIV infection and Pc colonization and demonstrated that Pc colonization correlated with COPD development. In the present study, we examined kinetics of COPD development in non-human primate and tested the effect of Pc burden reduction on pulmonary function by TMP-SMX treatment.

METHODS

Cynomolgus macaques (n = 16) were infected with simian/human immunodeficiency virus (SHIV89.6P), and natural Pc colonization was examined by nested polymerase chain reaction of serial bronchoalveolar lavage fluid and anti-Pc serology.

RESULTS

Eleven of 16 monkeys became Pc colonized by 16 weeks post simian-human immunodeficiency virus (SHIV) infection. Pc colonization of SHIV-infected monkeys led to progressive declines in pulmonary function as early as 4 weeks after Pc detection. SHIV-infected and Pc-negative monkeys maintained normal lung function. At 25 weeks post-SHIV infection, TMP-SMX treatment was initiated in 7 Pc-positive (Pc+) (TMP: 20 mg/kg and SMX: 100 mg/kg, daily for 48 weeks) and 5 Pc-negative (Pc-) monkeys. Four SHIV+/Pc+ remained untreated for the duration of the experiment. Detection frequency of Pc in serial bronchoalveolar lavage fluid (P < 0.001), as well as plasma Pc antibody titers (P = 0.02) were significantly reduced in TMP-SMX-treated macaques compared with untreated.

CONCLUSIONS

Reduction of Pc colonization by TMP-SMX treatment did not improve pulmonary function, supporting the concept that Pc colonization results in early, permanent obstructive changes in the lungs of immunosuppressed macaques.

The role of dendritic cells in the pathogenesis of cigarette smoke-induced emphysema in mice

Chronic Obstructive Pulmonary Disease (COPD) is an important lung and airway disease which affects the lives of around 200 million people worldwide. The pathological hallmark of COPD is emphysema and bronchiolitis and is based on the inflammatory response of the innate and adaptive immune system to the inhalation of toxic particles and gases. The inflamed airways of COPD patients contain several inflammatory cells including neutrophils, macrophages, T lymphocytes, and dendritic cells (DC). The potential role of DCs as mediators of inflammation in the airways of smokers and COPD patients is poorly understood. The current study investigated the role of DC subsets in an animal model of cigarette smoke-induced lung emphysema through the expansion or depletion of DC subsets. Expansion of both myeloid DC (mDC) and plasmacytoid DC (pDC) by Flt3L treatment induced a decline in macrophage numbers and increased the levels of fibroblast growth factor (FGF) and vascular endothelial growth factor (VEGF) in the bronchoalveolar lavage (BAL) fluid of smoke-exposed animals. The increase in the mean linear intercept (Lm) following Flt3L treatment was decreased by pDC depletion. In conclusion, pharmacological modulation of DC subsets may have an effect on the development of airway responses and emphysema as indicated by the decline in macrophage numbers and the increase in FGF and VEGF levels in the bronchoalveolar lavage fluid. Moreover, the depletion of pDCs decreased the Lm which might suggest a role for pDC in the pathogenesis of lung emphysema.

Human immunodeficiency virus-associated obstructive lung diseases

In the era of effective antiretroviral therapy (ART), epidemiologic studies have found that persons infected with human immunodeficiency virus (HIV) have a higher prevalence and incidence of chronic obstructive pulmonary disease than HIV-uninfected persons. In comparison with HIV-uninfected persons and those with well-controlled HIV disease, HIV-infected persons with poor viral control or lower CD4 cell count have more airflow obstruction, a greater decline in lung function, and possibly more severe diffusing impairment. This article reviews the evidence linking HIV infection to obstructive lung disease, and discusses management issues related to the treatment of obstructive lung disease in HIV-infected patients.

Role of mtDNA haplogroups in COPD susceptibility in a southwestern Han Chinese population

The interplay of a complex genetic basis with the environmental factors of chronic obstructive pulmonary disease (COPD) may account for the differences in individual susceptibility to COPD. Mitochondrial DNA (mtDNA) contributes to an individual's ability to resist oxidation, an important determinant that affects COPD susceptibility. To investigate whether mtDNA haplogroups play important roles in COPD susceptibility, the frequencies of mtDNA haplogroups and an 822-bp mtDNA deletion in 671 COPD patients and 724 control individuals from southwestern China were compared. Multivariate logistic regression analysis revealed that, whereas mtDNA haplogroups A and M7 might be associated with an increased risk for COPD (OR=1.996, 95% CI=1.149-2.831, p=0.006, and OR=1.754, 95% CI=1.931-2.552, p=0.021, respectively), haplogroups F, D, and M9 might be associated with a decreased risk for COPD in this population (OR=0.554, 95% CI=0.390-0.787, p=0.001; OR=0.758, 95% CI=0.407-0.965, p=0.002; and OR=0.186, 95% CI=0.039-0.881, p=0.034, respectively). Additionally, the increased frequency of the 822-bp mtDNA deletion in male cigarette-smoking subjects among COPD patients and controls of haplogroup D indicated that haplogroup D might increase an individual's susceptibility to DNA damage from external reactive oxygen species derived from heavy cigarette smoking. We conclude that haplogroups A and M7 might be risk factors for COPD, whereas haplogroups D, F, and M9 might decrease the COPD risk in this Han Chinese population.

NFE2L2 pathway polymorphisms and lung function decline in chronic obstructive pulmonary disease

An oxidant-antioxidant imbalance in the lung contributes to the development of chronic obstructive pulmonary disease (COPD) that is caused by a complex interaction of genetic and environmental risk factors. Nuclear erythroid 2-related factor 2 (NFE2L2 or NRF2) is a critical molecule in the lung's defense mechanism against oxidants. We investigated whether polymorphisms in the NFE2L2 pathway affected the rate of decline of lung function in smokers from the Lung Health Study (LHS)(n = 547) and in a replication set, the Vlagtwedde-Vlaardingen cohort (n = 533). We selected polymorphisms in NFE2L2 in genes that positively or negatively regulate NFE2L2 transcriptional activity and in genes that are regulated by NFE2L2. Polymorphisms in 11 genes were significantly associated with rate of lung function decline in the LHS. One of these polymorphisms, rs11085735 in the KEAP1 gene, was previously shown to be associated with the level of lung function in the Vlagtwedde-Vlaardingen cohort but not with decline of lung function. Of the 23 associated polymorphisms in the LHS, only rs634534 in the FOSL1 gene showed a significant association in the Vlagtwedde-Vlaardingen cohort with rate of lung function decline, but the direction of the association was not consistent with that in the LHS. In summary, despite finding several nominally significant polymorphisms in the LHS, none of these associations were replicated in the Vlagtwedde-Vlaardingen cohort, indicating lack of effect of polymorphisms in the NFE2L2 pathway on the rate of decline of lung function.

Assessing and monitoring urban resilience using COPD in Porto

BACKGROUND

COPD morbidity is a good example of how the urban form may interfere with a disease's severity. Then, it may play an important role as a stimulus to increase the acceptability of several policy actions that aim to upgrade urban resilience. Despite the multiple dimensions of wellbeing, health is surely a key variable attracting everyone's attention, which is thus more likely to be able to persuade people that actions that may at first seem undesirable are fundamental in improving urban sustainability and well-being.

METHODS

After creating a short list of socio-economic and environmental factors relating to the onset and aggravation of COPD, daily admissions distributions were compared using both a non-weighted and a weighted multi-criteria hierarchical analysis procedure.

RESULTS

Porto's COPD Social and Environmental Inequalities Index (SEII), calculated with a hierarchical analysis procedure, accurately illustrates a great relationship between COPD admissions and adverse urban form variables.

CONCLUSION

COPD may be an important communication tool to stimulate the acceptability of some otherwise unpopular planning measures to improve urban resilience (sustainability and well-being).

Genetic variants associated with the risk of chronic obstructive pulmonary disease with and without lung cancer

Chronic obstructive pulmonary disease (COPD) is a strong risk factor for lung cancer. Published studies about variations of genes encoding glutathione metabolism, DNA repair, and inflammatory response pathways in susceptibility to COPD were inconclusive. We evaluated 470 single-nucleotide polymorphisms (SNP) from 56 genes of these three pathways in 620 cases and 893 controls to identify susceptibility markers for COPD risk, using existing resources. We assessed SNP- and gene-level effects adjusting for sex, age, and smoking status. Differential genetic effects on disease risk with and without lung cancer were also assessed; cumulative risk models were established. Twenty-one SNPs were found to be significantly associated with risk of COPD (P < 0.01); gene-based analyses confirmed two genes (GCLC and GSS) and identified three additional genes (GSTO2, ERCC1, and RRM1). Carrying 12 high-risk alleles may increase risk by 2.7-fold; eight SNPs altered COPD risk without lung cancer by 3.1-fold and 4 SNPs altered the risk with lung cancer by 2.3-fold. Our findings indicate that multiple genetic variations in the three selected pathways contribute to COPD risk through GCLC, GSS, GSTO2, ERCC1, and RRM1 genes. Functional studies are needed to elucidate the mechanisms of these genes in the development of COPD, lung cancer, or both.

The association of SERPINE2 gene with COPD in a Chinese Han population

PURPOSE

Polymorphisms of several candidate genes have been studied and associated with the development of chronic obstructive pulmonary disease (COPD). One such candidate is the SERPINE2 (Serpin peptidase inhibitor, clade E member 2) gene.

MATERIALS AND METHODS

To assess whether the SERPINE2 gene is associated with COPD in a Chinese Han population. Samples were collected from a Chinese Han population and analyzed for the association of single nucleotide polymor phisms (SNPs) or haplotypes of SERPINE2 gene with COPD in a case-control study. Three SNPs including rs840088 G/A in intron 1, rs1438831 A/G in 5' upstream sequence and rs3795879 G/A in intron 3 were detected using the polymerase chain reaction (PCR)-based restriction fragment length polymorphism technique in 409 COPD subjects and 411 controls. Genotyping of the SREPINE2 polymorphisms at positions rs840088, rs1438831and rs3795879 was performed.

RESULTS

We found that none of the rs840088G/A, rs1438831G/A and rs3795879 G/A polymorphisms were associated with the disease. The p-values were 0.630, 0.208 and 0.398 respectively.

CONCLUSION

Our data suggested that there was no significant association between SERPINE2 polymorphism and COPD susceptibility in the Chinese Han population.

Genetics of COPD

Previous family studies suggested that genetic variation contributes to COPD susceptibility. The only gene proven to influence COPD susceptibility is SERPINA1, encoding α1-antitrypsin. Most studies on COPD candidate genes except SERPINA1, have not been consistently replicated. However, longitudinal studies of decline in lung function, meta-analyses of candidate gene studies, and family-based linkage analyses suggested that variants in EPHX1, GST, MMP12, TGFB1, and SERPINE2 were associated with susceptibility to COPD. A genome-wide association (GWA) study has recently demonstrated that CHRNA3/5 in 15q25 was associated with COPD compared with control smokers. It was of interest that the CHRNA3/5 locus was associated with nicotine dependence and lung cancer as well. The associations of HHIP on 4q31 and FAM13A on 4q22 with COPD were also suggested in GWA studies. Another GWA study has shown that BICD1 in 12p11 was associated with the presence or absence of emphysema. Although every genetic study on COPD has some limitations including heterogeneity in smoking behaviors and comorbidities, it has contributed to the progress in elucidating the pathogenesis of COPD. Future studies will make us understand the mechanisms underlying the polygenic disease, leading to the development of a specific treatment for each phenotype.

Neonatal hyperoxia contributes additively to cigarette smoke-induced chronic obstructive pulmonary disease changes in adult mice

The extent by which early postnatal lung injury contributes to the development of chronic obstructive pulmonary disease (COPD) in the adult is unclear. We hypothesized that exposure to hyperoxia during early postnatal life can augment lung changes caused by adult chronic cigarette smoke (CS) exposure. C57BL/6J mice (1 d old) were exposed to hyperoxia (O(2)) for 5 days. At 1 month of age, half of the O(2)-exposed mice and half of the control mice were placed in a CS chamber for 6 months. After exposure to CS, mice underwent quasi-static pressure-volume curve and mean chord length measurements; quantification of pro-Sp-c expression; and measurement of lung IL-8/ KC, CXCR2/IL8Rα, TNF-α, and IL-6 mRNA by real-time PCR. Adult mice exposed to O(2)+CS had significantly larger chord length measurements (P < 0.02) and lung volumes at 35 cm H(2)O (P < 0.05) compared with all other groups. They also had significantly less pro-Sp-c protein and surfactant protein C mRNA expression (P < 0.003). Mice exposed to O(2)+CS and CS-only mice had significantly higher lung resistance and longer mean time constants (P < 0.01), significantly more inflammatory cells in the bronchoalveolar lavage fluid (P < 0.03), and significantly higher levels of lung CXCR2/IL8Rα mRNA compared with mice not exposed to smoke (P < 0.02). We conclude that exposure to early postnatal hyperoxia contributed additively to CS-induced COPD changes in adult mice. These results may be relevant to a growing population of preterm children who sustained lung injury in the newborn period and may be exposed to CS in later life.

Association between the tumour necrosis factor-α-308G/A polymorphism and chronic obstructive pulmonary disease: an update

BACKGROUND AND OBJECTIVE

Previous studies have suggested that the -308A allele in the tumour necrosis factor-α (TNF-α) gene promoter (rs1800629) may be a potential risk factor for COPD. However, more recent findings have been inconsistent. In the present study, a meta-analysis was performed to assess the association between the TNF-α-308G/A single nucleotide polymorphism (SNP) and the risk of COPD.

METHODS

Published studies were retrieved from PubMed, EMBASE and other databases. All studies assessing the association between the TNF-α-308G/A SNP and the risk of COPD were assessed. Pooled ORs with 95% CIs were calculated.

RESULTS

In the 36 studies that met the inclusion criteria, 4975 patients and 6518 control subjects had been genotyped. The overall results showed that the association between the TNF-α-308G/A SNP and the risk of COPD was statistically significant for Asians (OR = 2.36, 95% CI: 1.84-3.02, P < 0.0001) but not for Caucasians (OR = 1.07, 95% CI: 0.91-1.25, P = 0.438). As smoking is one of the most important risk factors for COPD, a second meta-analysis that included only smokers (3018 patients and 2749 control subjects) was performed. This analysis confirmed that the association between the TNF-α-308G/A SNP and COPD was statistically significant for Asians (OR = 1.72, 95% CI: 1.14-2.61, P = 0.011) but not for Caucasians (OR = 1.16, 95% CI: 0.86-1.56, P = 0.33).

CONCLUSIONS

This meta-analysis suggests that the TNF-α-308A genotype is associated with an increased risk of COPD in Asian but not Caucasian populations. Further studies are necessary to evaluate the relationship between TNF-α polymorphisms and the risk of COPD.

Association of genetic polymorphism of GSTT1, GSTM1 and GSTM3 in COPD patients in a north Indian population

Environmental exposures and genetic susceptibility can contribute to lung function decline in chronic obstructive pulmonary disease (COPD). Cigarette smoking is the main etiological factor for decline in lung function in COPD. However, only 10-20% chronic smokers develop symptomatic COPD. Genetic susceptibility to COPD might depend upon the variation of enzyme activities that detoxify cigarette smoke components. We performed a case control study to assess the association of Glutathione- S-transferase T1(GSTT1),Glutathione- S-transferase M1 (GSTM1), and Glutathione-S-transferase M3(GSTM3) common polymorphisms with the susceptibility to COPD patient in a north India population. In the present study, the genotypes of 412 subjects, (204 COPD patients and 208 healthy controls) were analyzed. Statistical analysis revealed that the frequency of homozygous GSTM1 null genotype was found to be significant higher in COPD patients as compared with healthy controls (OR, 2.58; 95% CI, 1.73-3.84; P = 0.001), but there were no significant differences in the distribution of homozygous null GSTT1 and 3-bp deletion polymorphism (rs1799735) in intron 6 variant allele in GSTM3 between COPD patients and healthy controls. Our study results suggest that GSTM1 null polymorphism is associated with genetic susceptibility to COPD. Moreover, we also found association between this polymorphism with pulmonary function test in smokers as well as nonsmokers.

Role of elastases in the pathogenesis of chronic obstructive pulmonary disease: implications for treatment

Neutrophil elastase, metalloproteinases, and their inhibitors play an important role in the development of chronic obstructive pulmonary disease (COPD), resulting in extensive tissue damage and malfunctioning of the airways. Nearly fifty years after the protease-antiprotease imbalance hypothesis has been suggested for the cause of emphysema, it is still appealing, but it does not explain the considerable variation in the clinical expressions of emphysema. However, there are many recent research findings to support the imbalance hypothesis as will be shown in this review. Although limited, there might be openings for the treatment of the disease.

Aquaporin 5 polymorphisms and rate of lung function decline in chronic obstructive pulmonary disease

RATIONALE

Aquaporin-5 (AQP5) can cause mucus overproduction and lower lung function. Genetic variants in the AQP5 gene might be associated with rate of lung function decline in chronic obstructive pulmonary disease (COPD).

METHODS

Five single nucleotide polymorphisms (SNPs) in AQP5 were genotyped in 429 European American individuals with COPD randomly selected from the NHLBI Lung Health Study. Mean annual decline in FEV(1) % predicted, assessed over five years, was calculated as a linear regression slope, adjusting for potential covariates and stratified by smoking status. Constructs containing the wildtype allele and risk allele of the coding SNP N228K were generated using site-directed mutagenesis, and transfected into HBE-16 (human bronchial epithelial cell line). AQP5 abundance and localization were assessed by immunoblots and confocal immunofluorescence under control, shear stress and cigarette smoke extract (CSE 10%) exposed conditions to test for differential expression or localization.

RESULTS

Among continuous smokers, three of the five SNPs tested showed significant associations (0.02>P>0.004) with rate of lung function decline; no associations were observed among the group of intermittent or former smokers. Haplotype tests revealed multiple association signals (0.012>P>0.0008) consistent with the single-SNP results. In HBE16 cells, shear stress and CSE led to a decrease in AQP5 abundance in the wild-type, but not in the N228K AQP5 plasmid.

CONCLUSIONS

Polymorphisms in AQP5 were associated with rate of lung function decline in continuous smokers with COPD. A missense mutation modulates AQP-5 expression in response to cigarette smoke extract and shear stress. These results suggest that AQP5 may be an important candidate gene for COPD.

Polymorphism of SERPINE2 gene is associated with pulmonary emphysema in consecutive autopsy cases

Background

The SERPINA1, SERPINA3, and SERPINE2 genes, which encode antiproteases, have been proposed to be susceptible genes for of chronic obstructive pulmonary disease (COPD) and related phenotypes. Whether they are associated with emphysema is not known.

Methods

Twelve previously reported single nucleotide polymorphisms (SNPs) in SERPINA1 (rs8004738, rs17751769, rs709932, rs11832, rs1303, rs28929474, and rs17580), SERPINA3 (rs4934, rs17473, and rs1800463), and SERPINE2 (rs840088 and rs975278) were genotyped in samples obtained from 1,335 consecutive autopsies of elderly Japanese people. The association between these SNPs and the severity of emphysema, as assessed using macroscopic scores, was determined.

Results

Emphysema of more than moderate degree was detected in 189 subjects (14.1%) and showed a significant gender difference (males, 20.5% and females, 7.0%; p < 0.0001). Among the 12 examined SNPs, only rs975278 in the SERPINE2 gene was positively associated with emphysema. Unlike the major alleles, homozygous minor alleles of rs975278 were associated with emphysema (odds ratio (OR) = 1.54; 95% confidence interval (CI) = 1.02-2.30; p = 0.037) and the association was very prominent in smokers (OR = 2.02; 95% CI = 1.29-3.15; p = 0.002).

Conclusions

SERPINE2 may be a risk factor for the development of emphysema and its association with emphysema may be stronger in smokers.

Analyses of association between PPAR gamma and EPHX1 polymorphisms and susceptibility to COPD in a Hungarian cohort, a case-control study

Background

In addition to smoking, genetic predisposition is believed to play a major role in the pathogenesis of chronic obstructive pulmonary disease (COPD). Genetic association studies of new candidate genes in COPD may lead to improved understanding of the pathogenesis of the disease.

Methods

Two proposed casual single nucleotide polymorphisms (SNP) (rs1051740, rs2234922) in microsomal epoxide hydrolase (EPHX1) and three SNPs (rs1801282, rs1800571, rs3856806) in peroxisome proliferator-activated receptor gamma (PPARG), a new candidate gene, were genotyped in a case-control study (272 COPD patients and 301 controls subjects) in Hungary. Allele frequencies and genotype distributions were compared between the two cohorts and trend test was also used to evaluate association between SNPs and COPD. To estimate the strength of association, odds ratios (OR) (with 95% CI) were calculated and potential confounding variables were tested in logistic regression analysis. Association between haplotypes and COPD outcome was also assessed.

Results

The distribution of imputed EPHX1 phenotypes was significantly different between the COPD and the control group (P = 0.041), OR for the slow activity phenotype was 1.639 (95% CI = 1.08- 2.49; P = 0.021) in our study. In logistic regression analysis adjusted for both variants, also age and pack-year, the rare allele of His447His of PPARG showed significant association with COPD outcome (OR = 1.853, 95% CI = 1.09-3.14, P = 0.0218). In haplotype analysis the GC haplotype of PPARG (OR = 0.512, 95% CI = 0.27-0.96, P = 0.035) conferred reduced risk for COPD.

Conclusions

The "slow" activity-associated genotypes of EPHX1 were associated with increased risk of COPD. The minor His447His allele of PPARG significantly increased; and the haplotype containing the minor Pro12Ala and the major His447His polymorphisms of PPARG decreased the risk of COPD.

TNF-308 gene polymorphism is associated with COPD risk among Asians: meta-analysis of data for 6,118 subjects

Chronic obstructive pulmonary disease (COPD) is a complex polygenic disease in which gene-environment interactions play a critical role in disease onset and progression. The gene encoding tumor necrosis factor (TNF) is one of several candidate loci for the pathogenesis of COPD and is highly polymorphic. A number of studies have investigated the association between the TNF-308 polymorphisms and COPD risk in different populations, and resulted in inconsistent results. A systematic review and meta-analysis of the published studies were performed to gain a clearer understanding of this association. The PubMed, Embase, Web of Science, and CNKI databases were searched for case-control studies published from 1966 to April 2009. Data were extracted and pooled odds ratios (OR) with 95% confidence intervals (CI) were calculated. Twenty-four eligible studies, comprising 2,380 COPD cases and 3,738 controls, were included in the meta-analysis. The pooled result showed that the TNF-308 polymorphisms were significantly associated with an increased risk of COPD (OR=1.335, 95% CI: 1.172-1.522, for allele A carriers versus G/G; OR=1.330, 95% CI=1.174-1.505, for allele A versus allele G). Subgroup analysis supported the results in the Asian populations, but not in the Caucasian populations. When the analysis was limited to only those studies in which the COPD cases and controls were smokers/ex-smokers, the pooled results supported the conclusion. This meta-analysis suggested that the TNF-308 A allele is a more significant risk factor for developing COPD among Asian populations, but not among Caucasians.

Airways obstruction among older construction and trade workers at Department of Energy nuclear sites

BACKGROUND

A study of chronic obstructive pulmonary disease (COPD) among 7,579 current and former workers participating in medical screening programs at Department of Energy (DOE) nuclear weapons facilities through September 2008 was undertaken.

METHODS

Participants provided a detailed work and exposure history and underwent a respiratory examination that included a respiratory history, respiratory symptoms, a posterior-anterior (P-A) chest radiograph classified by International Labour Office (ILO) criteria, and spirometry. Statistical models were developed to generate group-level exposure estimates that were used in multivariate logistic regression analyses to explore the risk of COPD in relation to exposures to asbestos, silica, cement dust, welding, paints, solvents, and dusts/fumes from paint removal. Risk for COPD in the study population was compared to risk for COPD in the general US population as determined in National Health and Nutrition Examination Survey (NHANES III).

RESULTS

The age-standardized prevalence ratio of COPD among DOE workers compared to all NHANES III data was 1.3. Internal analyses found the odds ratio of COPD to range from 1.6 to 3.1 by trade after adjustment for age, race, sex, smoking, and duration of DOE employment. Statistically significant associations were observed for COPD and exposures to asbestos, silica, welding, cement dusts, and some tasks associated with exposures to paints, solvents, and removal of paints.

CONCLUSIONS

Our study of construction workers employed at DOE sites demonstrated increased COPD risk due to occupational exposures and was able to identify specific exposures increasing risk. This study provides additional support for prevention of both smoking and occupational exposures to reduce the burden of COPD among construction workers.

Genetics of chronic obstructive pulmonary disease: a succinct review, future avenues and prospective clinical applications

Chronic obstructive pulmonary disease (COPD) is influenced by genetic and environmental factors. A large number of candidate gene-association studies and genome-wide linkage scans have been conducted to elucidate the genetic architecture underlying this disease. The compilation of these studies clearly revealed the complex genetic nature of COPD. Multiple genes acting on specific environmental backgrounds are likely to be the tenet of this multifactorial disorder. Encouragingly, reproducible susceptibility genes, such as SERPINE2, were recently identified. Advances in genomic research offer unprecedented capabilities to interrogate the human genome and are likely to accelerate the discovery of new genes. A comprehensive catalogue of genes implicated in the pathogenesis of COPD has great potential to lead to the development of new therapies and explain interindividual response to treatment.

Association of CD40 -1C/T polymorphism in the 5'-untranslated region and chronic obstructive pulmonary disease

BACKGROUND

Chronic inflammation of the airways and lung parenchyma plays a major role in the pathogenesis of chronic obstructive pulmonary disease (COPD). It is influenced by both environmental and genetic factors. CD40 signaling has been linked to pathogenic processes of chronic inflammatory diseases. After interaction with its ligand CD154 (CD40L), CD40 induces a broad variety of chronic inflammatory responses, inducing the release of inflammatory mediators. We investigated whether a CD40 gene (-1C/T) single nucleotide polymorphism (SNP) is associated with COPD in a Chinese population.

METHODS

We analyzed -1C/T SNP of the CD40 gene in 234 patients with COPD, and also in 312 controls using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and DNA sequencing methods.

RESULTS

The frequency of CT and CT+CC of CD40 gene was significantly different from TT in the COPD group compared with the control group (for CT: OR=1.777, 95% CI: 1.117-2.826, p=0.015; for CT+CC: OR=1.614, 95% CI: 1.032-2.526, p=0.035). However, neither the allele frequency of CD40 nor the smoking and clinical stages in CD40 -1C/T genotypes frequency had significant differences between the COPD patients and control.

CONCLUSION

These findings suggest that the CD40 -1C/T polymorphism may contribute to the susceptibility to COPD in a Chinese population.

Translating the COPD transcriptome: insights into pathogenesis and tools for clinical management

While the role cigarette smoke plays in chronic obstructive pulmonary disease (COPD) is undisputed, the molecular mechanisms by which inhaled smoke contributes to disease pathogenesis remains unclear. One of the major barriers to effective approaches to diagnose and manage COPD is the remarkable heterogeneity displayed by patients with the disease. Whole-genome gene-expression studies of airway and lung tissue from patients with COPD provide an opportunity to gain insights into disease pathogenesis, allowing for both a molecular understanding of the pathogenic processes that contribute to this heterogeneity, and the ability to target therapies to these processes. This review focuses on synthesizing and integrating the limited numbers of high-throughput gene expression studies that have been conducted on lung tissue and airway samples from smokers with COPD. Comparing several lung tissue studies using computational approaches, we find that the results suggest fundamental similarities and identify common biological processes underlying COPD, despite each study having identified largely nonoverlapping lists of differentially expressed genes. Given these similarities, we argue that additional lung tissue and airway gene-expression studies are warranted, and present a roadmap for how such studies could lead to clinically relevant tools that would impact COPD management.