A polymorphism in the tumor necrosis factor-alpha gene promoter region may predispose to a poor prognosis in COPD

The Molecular Blueprint for Chronic Obstructive Pulmonary Disease (COPD): A New Paradigm for Diagnosis and Therapeutics

The global prevalence of chronic obstructive pulmonary disease (COPD) has increased over the last decade and has emerged as the third leading cause of death worldwide. It is characterized by emphysema with prolonged airflow limitation. COPD patients are more susceptible to COVID-19 and increase the disease severity about four times. The most used drugs to treat it show numerous side effects, including immune suppression and infection. This review discusses a narrative opinion and critical review of COPD. We present different aspects of the disease, from cellular and inflammatory responses to cigarette smoking in COPD and signaling pathways. In addition, we highlighted various risk factors for developing COPD apart from smoking, like occupational exposure, pollutants, genetic factors, gender, etc. After the recent elucidation of the underlying inflammatory signaling pathways in COPD, new molecular targeted drug candidates for COPD are signal-transmitting substances. We further summarize recent developments in biomarker discovery for COPD and its implications for disease diagnosis. In addition, we discuss novel drug targets for COPD that could be explored for drug development and subsequent clinical management of cardiovascular disease and COVID-19, commonly associated with COPD. Our extensive analysis of COPD cause, etiology, diagnosis, and therapeutic will provide a better understanding of the disease and the development of effective therapeutic options. In-depth knowledge of the underlying mechanism will offer deeper insights into identifying novel molecular targets for developing potent therapeutics and biomarkers of disease diagnosis.

Association between single-nucleotide polymorphism of cytokines genes and chronic obstructive pulmonary disease: A systematic review and meta-analysis

Chronic obstructive pulmonary disease (COPD) is a common chronic inflammatory disease with high morbidity and mortality rates worldwide. Cytokines, which are the main regulators of immune responses, play crucial roles in inflammatory diseases such as COPD. Moreover, certain genetic variations can alter cytokine expression, and changes in cytokine level or function can affect disease susceptibility. Therefore, investigating the association between genetic variations and disease progression can be useful for prevention and treatment. Several studies have explored the association between common genetic variations in cytokine genes and COPD susceptibility. In this study, we summarized the reported studies and, where possible, conducted a systematic review and meta-analysis to evaluate the genetic association between various cytokines and COPD pathogenesis. We extracted relevant articles from PubMed and Google Scholar databases using a standard systematic search strategy. We included a total of 183 studies from 78 separate articles that evaluated 50 polymorphisms in 12 cytokine genes in this study. Our analysis showed that among all reported cytokine polymorphisms (including TNF-α, TGF-β, IL1, IL1RN, IL4, IL4R, IL6, IL10, IL12, IL13, IL17, IL18, IL27, and IL33), only four variants, including TNF-α-rs1800629, TGF-β1-rs6957, IL13-rs1800925, and IL6-rs1800796, were associated with the risk of COPD development. This updated meta-analysis strongly supports the association of TNF-α-rs1800629, TGF-β1-rs6957, IL13-rs1800925, and IL6-rs1800796 variants with a high risk of COPD.

Association Between TNF-α-308, +489, -238 Polymorphism, and COPD Susceptibility: An Updated Meta-Analysis and Trial Sequential Analysis

The tumor necrosis factor alpha (TNF-α) polymorphism may play an important role in chronic obstructive pulmonary disease (COPD) susceptibility. However, the results are still inconclusive. Eligible studies were searched in Cochrane Library database, EMBASE, Pudmed, Web of science, China National Knowledge Infrastructure, and Wanfang database. Finally, a total of 27 case-control studies with 3473 COPD cases and 4935 controls were included in the present analysis. We also performed trial sequential analysis (TSA) to confirm our results. Overall, association between TNF-α-308G/A polymorphism and COPD susceptibility was identified in allelic model (A vs. G, OR = 1.21, 95%CI: 1.01-1.45, p = 0.04) when smoking status was not adjusted. In ethnicity subgroup analysis, we found that the TNF-α -308G/A polymorphism was associated to COPD among Asians (GA vs. GG, OR = 1.35, 95%CI: 1.04-1.77, p = 0.02) when smoking status was not adjusted. However, no significant association was found in Asian smokers or Caucasian smokers. In conclusion, our study suggest that TNF-α-308 GA genotype is related to COPD in the Asian population. In addition, the TNF-α+489G/A, - 238G/A variants do not increase the risk of COPD. Systematic Review Registration: https://www.crd.york.ac.uk/PROSPERO/, identifier CRD42021273980.

Correlation between TNF-α -308 and +489 Gene Polymorphism and Acute Exacerbation of Chronic Obstructive Pulmonary Diseases

Acute exacerbation of chronic obstructive pulmonary disease (AECOPD) is becoming a common respiratory disease, leading to increased morbidity and mortality worldwide. Tumor necrosis factor-alpha (TNF-α) is a powerful proinflammatory cytokine involved in the pathogenesis of AECOPD. Therefore, we proposed a close correlation between the TNF-α polymorphism [-308G/A (rs1800629), +489G/A (rs1800610)] and the disease progress of patients with AECOPD. Comparison of the TNF-α genotypes between the 198 AECOPD diagnosed patients groups and 195 healthy peoples suggested their significant differences of the three genotypes (AA, GA, GG) distribution for TNF-α -308 (P < 0.05), but no differences of that for TNF-α +489. We found that patients with TNF-α -308 GA/AA genotypes showed smaller adjacent arterial diameter, thicker bronchial wall, higher bronchial artery ratio, higher bronchial wall grading, and higher frequency of acute exacerbations than those with TNF-α -308 GG genotype. Patients with TNF-α +489 GA/AA genotypes showed the same AECOPD properties as patients with TNF-α -308 except for the high frequency of acute exacerbations. Further experiment showed that the TNF-α -308 and+489 gene polymorphisms could affect the expression level of TNF-α in macrophages, suggesting the involvement of the macrophage population in disease regulation of AECOPD patients with TNF-α -308G/A and+489G/A genotype heterogeneity. In conclusion, the TNF-α -308 G/A genotype was related to AECOPD susceptibility and progress, while the TNF-α +489G/A genotype was related to AECOPD progress, but not AECOPD susceptibility.

Oxidative Stress Mechanisms in the Pathogenesis of Environmental Lung Diseases

Globally, respiratory diseases are major cause of disability and mortality, and more alarmingly, it disproportionately affects developing countries, which is largely attributed to poor quality of air. Tobacco smoke and emissions from combustion of fossil fuel and biomass fuel are the major airborne pollutants affecting human lung health. Oxidative stress is the dominant driving force by which the airborne pollutants exert their toxicity in lungs and cause respiratory diseases. Most airborne pollutants are associated with intrinsic oxidative potential and, additionally, stimulate endogenous production of reactive oxygen species (ROS) and reactive nitrogen species (RNS). Elevated ROS and RNS in lungs modulate redox signals and cause irreversible damage to critical biomolecules (lipids, proteins and DNA) and initiate various pathogenic cellular process. This chapter provides an insight into oxidative stress-linked pathogenic cellular process such as lipid peroxidation, inflammation, cell death, mitochondrial dysfunction, endoplasmic reticulum stress, epigenetic changes, profibrotic signals and mucus hypersecretion, which drive the development and progression of lung diseases. Lungs are associated with robust enzymatic and non-enzymatic (GSH, ascorbic acid, uric acid, vitamin E) antioxidant defences. However, sustained production of free radicals due to continuous exposures to airborne pollutants overwhelms lung antioxidant defences and causes oxidative injury. Preclinical studies have demonstrated the critical roles and therapeutic potential of upregulating lung antioxidants for intervention of respiratory diseases; however, so far clinical benefits in antioxidant supplementation trials have been minimal and conflicting. Antioxidants alone may not be effective in treatment of respiratory diseases; however it could be a promising adjunctive therapy.

TNF-α -308 G/A variant and susceptibility to chronic obstructive pulmonary disease: A systematic review and meta-analysis

BACKGROUND AND OBJECTIVE

TNF-α -308 G/A variant is recognized to play an important role in the pathogenesis of chronic obstructive pulmonary disease (COPD). Although many studies have investigated the association of TNF-α-308 and COPD risk, a deep understanding of this association is lacking due to small subjects sizes and insufficiently study designs among different investigations. In this study, a systematic review and meta-analysis was performed based on published reports on the association of TNF-α and COPD.

METHOD

The published studies concerned the association between TNF-α and COPD were identified using a systematic research in Scopus, Google Scholar, and PubMed up to April 2018. A total of 46 different papers studying the rs1800629 variant in TNF-α gene were included. Then, human studies were selected to further analysis regardless of papers language.

RESULTS

Based on the results, the major outcome of this meta-analysis can be represented as follows: individuals with GG and GA genotypes possess less risk of developing COPD (OR = 0.58, 95%CI: (0.44-0.79), P < 0.00) compared to AA genotype carriers. In contrast, the AA genotype carriers of the TNF-α rs1800629 has a significantly higher risk of developing COPD (OR = 1.83, 95%CI: (1.34-2.51), P < 0.00) compared to GG carrier. Despite the previous meta-analysis results which reported significantly decreasing of heterogeneity with ethnicity, we found that the source of controls has a significant contribution to observed heterogeneity.

CONCLUSIONS

Thanks to the global burden of COPD studies, proving TNF-α 308 gene variant as an independent factor in its pathogenesis opens new insights to diagnosis and management of COPD.

Genetic polymorphism and chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is a common chronic disease, and its morbidity and mortality are increasing. There are many studies that have tried to explain the pathogenesis of COPD from genetic susceptibility, to identify the susceptibility of COPD factors, which play a role in early prevention, early detection and the early treatment. However, it is well known that COPD is an inflammatory disease characterized by incomplete reversible airflow limitation in which genes interact with the environment. In recent years, many studies have proved gene polymorphisms and COPD correlation. However, there is less research on the relationship between COPD and genome-wide association study (GWAS), epigenetics and apoptosis. In this paper, we summarized the correlation between gene level and COPD from the following four aspects: the GWAS, the gene polymorphism, the epigenetics and the apoptosis, and the relationship between COPD and gene is summarized comprehensively.

Comparative efficacy of long-acting β2-agonists as monotherapy for chronic obstructive pulmonary disease: a network meta-analysis

PURPOSE

Long-acting β2-agonists (LABAs) have demonstrated efficacy in patients with COPD in clinical trials. The purpose of this study was to assess the comparative efficacy of all available dosages of all LABA monotherapies using a network meta-analysis.

METHODS

A systematic literature review identified 33 randomized controlled trials of LABA monotherapies (salmeterol 50 μg twice daily [BID]; formoterol 12 μg BID; indacaterol 75, 150, and 300 μg once daily [OD]; olodaterol 5 and 10 μg OD, and vilanterol 25 μg OD). Clinical efficacy was evaluated at 12 and 24 weeks in terms of trough forced expiratory volume in 1 second (FEV₁), transition dyspnea index focal score, St George's Respiratory Questionnaire total score, and rate of COPD exacerbations. The relative effectiveness of all LABA monotherapies was estimated by Bayesian network meta-analysis.

RESULTS

At 12 and 24 weeks, indacaterol 300 and 150 μg OD were associated with statistically significant improvement in trough FEV₁ compared to all other LABA monotherapies; vilanterol 25 μg OD was superior to formoterol 12 μg BID. At 12 weeks, indacaterol 75 μg OD was associated with significant improvement in trough FEV₁ compared to formoterol 12 μg BID and olodaterol (5 and 10 μg OD); salmeterol 50 μg BID was superior to formoterol 12 μg BID and olodaterol 5 μg OD. Indacaterol 300 μg OD was also associated with significant improvement in transition dyspnea index focal score compared to all other LABAs at 12 or 24 weeks. Indacaterol 150 μg OD had significantly better results in exacerbation rates than olodaterol 5 μg and olodaterol 10 μg OD.

CONCLUSION

Indacaterol 300 μg, followed by 150 and 75 μg, were the most effective LABA monotherapies for moderate to severe COPD.

Tristetraprolin Down-Regulation Contributes to Persistent TNF-Alpha Expression Induced by Cigarette Smoke Extract through a Post-Transcriptional Mechanism

Rationale

Tumor necrosis factor-alpha (TNF-α) is a potent pro-inflammatory mediator and its expression is up-regulated in chronic obstructive pulmonary disease (COPD). Tristetraprolin (TTP) is implicated in regulation of TNF-α expression; however, whether TTP is involved in cigarette smoke-induced TNF-α expression has not been determined.

Methods

TTP expression was examined by western blot analysis in murine alveolar macrophages and alveolar epithelial cells challenged without or with cigarette smoke extract (CSE). TNF-α mRNA stability, and the decay of TNF-α mRNA, were determined by real-time quantitative RT-PCR. TNF-α protein levels were examined at the same time in these cells. To identify the molecular mechanism involved, a construct expressing the human beta-globin reporter mRNA containing the TNF-α 3’-untranslated region was generated to characterize the TTP targeted site within TNF-α mRNA.

Results

CSE induced TTP down-regulation in alveolar macrophages and alveolar epithelial cells. Reduced TTP expression resulted in significantly increased TNF-α mRNA stability. Importantly, increased TNF-α mRNA stability due to impaired TTP function resulted in significantly increased TNF-α levels in these cells. Forced TTP expression abrogated the increased TNF-α mRNA stability and expression induced by CSE. By using the globin reporter construct containing TNF-α mRNA 3’-untranslated region, the data indicate that TTP directly targets the adenine- and uridine-rich region (ARE) of TNF-α mRNA and negatively regulates TNF-α expression at the post-transcriptional level.

Conclusion

The data demonstrate that cigarette smoke exposure reduces TTP expression and impairs TTP function, resulting in significantly increased TNF-α mRNA stability and excessive TNF-α expression in alveolar macrophages and epithelial cells. The data suggest that TTP is a novel post-transcriptional regulator and limits excessive TNF-α expression and inflammatory response induced by cigarette smoke.

Association between TNF-α -308 G/A polymorphism and COPD susceptibility: a meta-analysis update

Background and objective

The association between TNF-α −308 G/A polymorphism and COPD remains controversial due to insufficiently strict study designs and small group sizes among different studies. In the present study, a meta-analysis update which followed a stricter procedure was performed to obtain a clearer understanding of this association.

Methods

A comprehensive database search was conducted to identify the case–control studies published up to July 2015 which reported an association between the TNF-α −308 G/A polymorphism and COPD risk. Data were extracted to calculate pooled odds ratios with 95% confidence intervals under the most appropriate genetic and allelic models. Sensitivity was analyzed, and heterogeneity as well as publication bias was assessed.

Results

Thirty-eight eligible studies, comprising 3,951 COPD cases and 5,110 controls, were included in this study, among which 22 studies comprising 2,067 COPD cases and 2,167 controls were performed in Asians, and 16 studies comprising 1,884 COPD cases and 2,943 controls were in non-Asians. The overall result showed that TNF-α −308 G/A polymorphisms were significantly associated with increased COPD risk in both the codominant genetic and allelic models. Individuals with the GA or AA genotype were more susceptible to COPD development than those with the GG genotype. In addition, individuals with the AA genotype were more susceptible to developing COPD than those with the GA genotype. The subgroup analysis stratified by ethnicity supported the results in Asians but not in non-Asians. However, no association was found between TNF-α −308 G/A polymorphisms and COPD susceptibility either in Asians or in non-Asians in the meta-analysis conducted with restriction to former/current smokers.

Conclusion

The present meta-analysis suggested that the TNF-α −308 G/A polymorphism was associated with an increased risk of COPD among Asians but not in non-Asians. Furthermore, individuals with the AA genotype of TNF-α −308 were more susceptible to developing COPD.

Tumor necrosis factor-α (TNF-α)-308G/A promoter polymorphism in colorectal cancer in ethnic Kashmiri population - A case control study in a detailed perspective

Background

Inflammation constitutes one of the important components of colorectal cancer (CRC) pathogenesis. Tumor necrosis factor-α (TNF-α), a cytokine and an important inflammatory mediator plays a pivotal role in the malignant cellular proliferation, angiogenesis, tissue invasion and metastasis in CRC. The studies on association of various polymorphisms in human TNF-α gene including TNF-α-308G/A single nucleotide polymorphism (SNP) are limited, mixed and inconclusive.

Materials and methods

The aim of this study was to analyze the association of TNF-α-308G/A promoter SNP with colorectal cancer (CRC) susceptibility and development risk and also to evaluate the modifying effects of possible TNF-α-308G/A genotypes on different risk factors of CRC in ethnic population of Kashmir, India through a case–control setup. The genotype frequencies of TNF-α-308G/A promoter SNP were compared between 142 CRC patients and 184 individually matched healthy controls by using polymerase chain reaction and restriction fragment length polymorphism (PCR-RFLP) method. The associations between the TNF-α-308G/A SNP and CRC risk were examined through conditional logistic regression models adjusted for multiple possible confounding (third) variables. Further, the associations between this SNP and various clinico-pathological parameters, demographic variables and environmental factors within the case group subjects with regard to CRC risk were also evaluated.

Results

The association between the TNF-α-308G/A SNP and the modulation of risk of CRC was not found to be significant (p value = 0.156). The effect of less common TNF-α-308A allele on the risk of colorectal cancer was also not found to be significant (p value = 0.175). The variant genotype (AA) was nonexistent in the study population. Further, we found no significant effect modulation of CRC risk by wild and heterozygous TNF-α-308G/A SNP genotypes in presence of different possible risk factors (p > 0.05). We also found no significant association of TNF-α-308G/A SNP with the subsets of various characteristics of the case group subjects under study (p > 0.05).

Conclusions

This study indicates that there is no significant association between the TNF-α-308G/A promoter SNP and the risk of developing CRC in ethnic Kashmiri population. However, in order to substantiate our findings, this study needs to be replicated with bigger sample size and should involve other ethnically defined populations with high CRC risk.

Role of oxidative stress & transient receptor potential in chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) affect millions of people worldwide and is known to be one of the leading causes of death. The highly sensitive airways protect themselves from irritants by cough and sneeze which propel endogenous and exogenous substances to minimize airway noxious effects. One noxious effect of these substances is activation of peripheral sensory nerve endings of nociceptor neurons innervating these airways lining thus transmitting dangerous signals from the environment to the central nervous system (CNS). Nociceptor neurons include transient receptor potential (TRP) ion channels, especially the vanilloid and ankyrin subfamilies, TRPV1/A1 which can be activated by noxious chemical challenges in models of airways disease. As oxidative stress may activate airways sensory neurons and contribute to COPD exacerbations we sought to review the role that TRP channel activation by oxidative signals may have on airway responses. It would be prudent to target the TRP channels with antagonists and lower systemic oxidative stress with agents that can modulate TRP expression and boost the endogenous levels of antioxidants for treatment and management of COPD.

Tumor necrosis factor-α driven inflammation in alpha-1 antitrypsin deficiency: a new model of pathogenesis and treatment

Alpha-1 antitrypsin (AAT) deficiency (AATD) has traditionally been thought of as a genetic disorder characterized by lung destruction and early emphysema in a low AAT, and high neutrophil elastase (NE) environment in the lungs of affected individuals. Recently, a growing body of evidence has emerged to support the hypothesis that tumor necrosis factor alpha (TNF-α) is essential in the pathogenesis of both genetic AATD and non-genetic chronic obstructive pulmonary disease (COPD). Reports have highlighted the importance of TNF-α driven immune cell dysfunction in the development of lung disease in AATD. The authors discuss the role of AAT as a key modulator of TNF-α signaling firstly in the setting of AATD and secondly in other conditions where AAT augmentation therapy has potential utility as a novel therapy.

Identification of MMP-9 as a biomarker for detecting progression of chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is a complex immunological disease with multiple pathological features that is primarily induced by smoking together with additional genetic risk factors. COPD is frequently underdiagnosed; forced expiratory volume in the first second (FEV1) is considered to be the main diagnostic measure for COPD, yet it is insufficiently sensitive to monitor disease progression. Biomarkers capable of monitoring COPD progression and severity are needed. In this report, we evaluated matrix metalloproteinase-9 (MMP-9) as an early marker for the detection and staging of COPD, by assessing the mRNA levels of MMP-9 in peripheral blood samples collected from 22 COPD patients, 6 asymptomatic smokers, and 5 healthy controls. Our results demonstrate that the mRNA levels of MMP-9 increased more than two-fold in severe COPD relative to non-COPD smokers or moderate COPD groups. Moreover, in the very severe COPD group, MMP-9 mRNA levels showed a 4-fold increase relative to the non-COPD smokers or the moderate COPD groups, while there was a mild increase (∼40%) when compared to the severe COPD group. Taken together, our results suggest that MMP-9 serves as a biomarker for the grade and severity of COPD.

Electronic health records and improved nursing management of chronic obstructive pulmonary disease

This paper identifies evolving trends in the diagnosis and treatment of chronic obstructive pulmonary disease (COPD), and recommends the integration of nursing strategies in COPD management via widespread implementation of electronic health records. COPD is a complex lung disease with diverse origins, both physical and behavioral, manifested in a wide range of symptoms that further increase the patient's risk for comorbidities. Early diagnosis and effective management of COPD require monitoring of a dizzying array of COPD symptoms over extended periods of time, and nurses are especially well positioned to manage potential progressions of COPD, as frontline health care providers who obtain, record, and organize patient data. Developments in medical technology greatly aid nursing management of COPD, from the deployment of spirometry as a diagnostic tool at the family practice level to newly approved treatment options, including non-nicotine pharmacotherapies that reduce the cravings associated with tobacco withdrawal. Among new medical technologies, electronic health records have proven particularly advantageous in the management of COPD, enabling providers to gather, maintain, and reference more patient data than has ever been possible before. Thus, consistent and widespread implementation of electronic health records facilitates the coordination of diverse treatment strategies, resulting in increased positive health outcomes for patients with 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.

The -308 G/A polymorphism in the tumor necrosis factor-α gene is not associated with development and progression of rheumatoid arthritis in Argentinean patients

AIM

A polymorphism in the tumor necrosis factor-alpha (TNF-α) promoter region has been associated with disease susceptibility and progression in rheumatoid arthritis (RA). The presence of an adenosine (TNF2 allele) instead of a guanine (TNF1 allele) at position -308 may be responsible for a general increase in the transcriptional activity of the TNF-α gene. Our aim was to evaluate the association of the TNF2 allele with the risk of disease development and/or progression of RA in an Argentine population cohort.

METHODS

Two hundred and twenty-three consecutive patients with RA according to the 1987 criteria of the American College of Rheumatology were included in the study. Clinical variables, Disease Activity Score 28, Health Assessment Questionnaire and Rheumatoid Arthritis Quality of Life were recorded. The radiographic erosions were determined by the method of Sharp/van der Heijde. A group of 111 healthy subjects matched by sex and age was used as a control. All samples were genotyped for the -308 G/A TNF-α polymorphism.

RESULTS

No significant differences were observed either in the frequency of the TNF2 allele or in the genotypic distributions of the -308 G/A TNF-α polymorphism (P > 0.05) between the control group and the RA patients. No association was found between the TNF2 allele and the variables related to the course and outcome of the disease (P > 0.05).

CONCLUSION

In this cohort of Argentinean patients with RA, the TNF2 allele was neither associated with susceptibility to the disease nor was it associated with the variables related to the course and outcome of the disease.

Gene polymorphisms and chronic obstructive pulmonary disease

The genetic component was suggested to contribute to the development of chronic obstructive pulmonary disease (COPD), a major and growing public health burden. The present review aims to characterize the evidence that gene polymorphisms contribute to the aetiology of COPD and related traits, and explore the potential relationship between certain gene polymorphisms and COPD susceptibility, severity, lung function, phenotypes, or drug effects, even though limited results from related studies lacked consistency. Most of these studies were association studies, rather than confirmatory studies. More large-sized and strictly controlled studies are needed to prove the relationship between gene polymorphisms and the reviewed traits. More importantly, prospective confirmatory studies beyond initial association studies will be necessary to evaluate true relationships between gene polymorphisms and COPD and help individualized treatment for patients with COPD.

Long-term safety study of infliximab in moderate-to-severe chronic obstructive pulmonary disease

RATIONALE

There was an increased number of malignancies in infliximab-treated (5.7%) over placebo-treated (1.3%) patients in a 44-week, phase 2 clinical study of 234 patients with moderate-to-severe chronic obstructive pulmonary disease (COPD).

OBJECTIVES

To collect malignancy and mortality data from completed clinical studies of infliximab in COPD treatment.

METHODS

The multicenter, observational Remicade Safety Under Long-Term Study in COPD (RESULTS COPD) collected malignancy and mortality data every six months for five years from patients who received ≥1 study-agent dose in a phase 2 study. Co-primary endpoints were the number of patients with malignancy and the number of deaths. Secondary endpoints included the number of patients with a malignancy according to malignancy type.

RESULTS

There was a gap period between the end of the phase 2 study and the initiation of RESULTS COPD, during which six malignancies and 14 deaths were reported spontaneously for the 107 (45.7%) of 234 patients with long-term safety information. Twenty-eight patients (overall 12.0%; placebo 10.4%, infliximab 12.7%) reported malignancies, including 12 patients during RESULTS COPD. Twenty-six patients (overall 11.1%; placebo 9.1%, infliximab 12.1%) died, including nine during RESULTS COPD. Lung cancer was the most common malignancy type (placebo n = 2; infliximab n = 10).

CONCLUSIONS

The greater proportion of malignancies observed with infliximab versus placebo in a phase 2 study diminished over the long-term follow-up. Due to the observational nature, limited patient participation, potential reporting bias from the interim spontaneous reporting period, and unblinding of all patients, more definitive conclusions cannot be drawn.

Updates on the COPD gene list

A genetic contribution to develop chronic obstructive pulmonary disease (COPD) is well established. However, the specific genes responsible for enhanced risk or host differences in susceptibility to smoke exposure remain poorly understood. The goal of this review is to provide a comprehensive literature overview on the genetics of COPD, highlight the most promising findings during the last few years, and ultimately provide an updated COPD gene list. Candidate gene studies on COPD and related phenotypes indexed in PubMed before January 5, 2012 are tabulated. An exhaustive list of publications for any given gene was looked for. This well-documented COPD candidate-gene list is expected to serve many purposes for future replication studies and meta-analyses as well as for reanalyzing collected genomic data in the field. In addition, this review summarizes recent genetic loci identified by genome-wide association studies on COPD, lung function, and related complications. Assembling resources, integrative genomic approaches, and large sample sizes of well-phenotyped subjects is part of the path forward to elucidate the genetic basis of this debilitating disease.

Association of TNF-α -308G/A, SP-B 1580 C/T, IL-13 -1055 C/T gene polymorphisms and latent adenoviral infection with chronic obstructive pulmonary disease in an Egyptian population

INTRODUCTION

Chronic obstructive pulmonary disease (COPD) is a leading cause of disability and death. The most common cause of COPD is smoking. There is evidence suggesting that genetic factors influence COPD susceptibility and variants in several candidate genes have been significantly associated with COPD. In this study, we aimed to investigate the possible association of the TNF-α -308, SPB+1580, IL-13 -1055 gene polymorphisms and latent adenovirus C infection with COPD in an Egyptian population.

MATERIAL AND METHODS

Our study included 115 subjects (75 smokers with COPD, 25 resistant smokers and 15 non-smokers) who were subjected to spirometric measurements, identification of adenovirus C and genotyping of TNF-α -308G/A, SP-B+1580 C/T and IL-13 -1055 C/T polymorphisms by real-time PCR.

RESULTS

The adenovirus C gene was identified in all subjects. The distribution of TNF-α genotypes showed no significant differences between different groups. However, homozygous A genotype was associated with a significant decrease in FEV(1), FEV(1)/FVC and FEF25/75% of predicted in COPD (p < 0.05). As regards SP-B genotypes, resistant smokers had a significantly higher homozygous T genotype frequency compared to COPD and non smokers (p = 0.005). Interleukin 13 genotypes showed no significant difference between different groups. There was a significant decrease in FEF25/75% of predicted in T allele carriers in COPD patients (p = 0.001).

CONCLUSIONS

The COPD is a disease caused by the interaction of combined genes and environmental influences, in the presence of smoking and latent adenovirus C infection, TNF-α -308A, SPB +1580 T and IL-13 -1055 T polymorphisms predispose to the development of COPD.

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.

TNF-α and TNF-β Gene Polymorphism in Saudi Rheumatoid Arthritis Patients

BACKGROUND

Tumor necrosis factor (TNF)-α and -β are cytokines with a wide range of inflammatory, apoptotic and immunomodulatory activities. TNF-α promoter -308 G < A polymorphism has been reported to be associated with rheumatoid arthritis (RA) with inconsistent results.

OBJECTIVE

The aim of this study is to elucidate a possible association of TNF-α (G-308A) and TNF-β (A+252G) polymorphisms with the susceptibility of RA in Saudi patients.

PATIENTS AND METHODS

This case control study consisted of 232 Saudi subjects including 106 RA patients and 126 matched controls. Genomic DNA was extracted using QIAamp(R) DNA mini kit (Qiagen CA, USA). TNF-α and TNF-β genes were amplified using Arms primers.

RESULTS

The frequencies of TNF-α (-308) allele G and genotype GG were significantly higher in RA patients as compared to controls while allele A and genotype AA were predominant in control group. On the other hand the frequency of TNF-β (+252) GG and AA genotypes were significantly higher in RA patients as compared to controls while GA genotype was predominant in controls. It was inferred that genotype GG positive individuals at position -308 of TNF-α were susceptible to RA while genotype AA might has a protective effect on RA susceptibility in Saudis. Whereas GG and AA genotype of TNF-β at +252 position might exert additive susceptibility to RA and GA might be refractory. However, there was no significant association between duration of morning stiffness, RF positivity and number of joints involved and distribution of alleles/genotypes of TNF-α (-308) or TNF-β (+252) polymorphism. It may be concluded that the TNF-α (-308) and TNF-β (+252) polymorphisms might influence the susceptibility to RA in Saudi population. These results might have prognostic value for future clinical observations.

An agent-based model of inflammation and fibrosis following particulate exposure in the lung

Inflammation and airway remodeling occur in a variety of airway diseases. Modeling aspects of the inflammatory and fibrotic processes following repeated exposure to particulate matter may provide insights into a spectrum of airway diseases, as well as prevention/treatment strategies. An agent-based model (ABM) was created to examine the response of an abstracted population of inflammatory cells (nominally macrophages, but possibly including other inflammatory cells such as lymphocytes) and cells involved in remodeling (nominally fibroblasts) to particulate exposure. The model focused on a limited number of relevant interactions, specifically those among macrophages, fibroblasts, a pro-inflammatory cytokine (TNF-α), an anti-inflammatory cytokine (TGF-β1), collagen deposition, and tissue damage. The model yielded three distinct states that were equated with (1) self-resolving inflammation and a return to baseline, (2) a pro-inflammatory process of localized tissue damage and fibrosis, and (3) elevated pro- and anti-inflammatory cytokines, persistent tissue damage, and fibrosis outcomes. Experimental results consistent with these predicted states were observed in histology sections of lung tissue from mice exposed to particulate matter. Systematic in silico studies suggested that the development of each state depended primarily upon the degree and duration of exposure. Thus, a relatively simple ABM resulted in several, biologically feasible, emergent states, suggesting that the model captures certain salient features of inflammation following exposure of the lung to particulate matter. This ABM may hold future utility in the setting of airway disease resulting from inflammation and fibrosis following particulate exposure.

Current concepts on oxidative/carbonyl stress, inflammation and epigenetics in pathogenesis of chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is a global health problem. The current therapies for COPD are poorly effective and the mainstays of pharmacotherapy are bronchodilators. A better understanding of the pathobiology of COPD is critical for the development of novel therapies. In the present review, we have discussed the roles of oxidative/aldehyde stress, inflammation/immunity, and chromatin remodeling in the pathogenesis of COPD. An imbalance of oxidants/antioxidants caused by cigarette smoke and other pollutants/biomass fuels plays an important role in the pathogenesis of COPD by regulating redox-sensitive transcription factors (e.g., NF-κB), autophagy and unfolded protein response leading to chronic lung inflammatory response. Cigarette smoke also activates canonical/alternative NF-κB pathways and their upstream kinases leading to sustained inflammatory response in lungs. Recently, epigenetic regulation has been shown to be critical for the development of COPD because the expression/activity of enzymes that regulate these epigenetic modifications have been reported to be abnormal in airways of COPD patients. Hence, the significant advances made in understanding the pathophysiology of COPD as described herein will identify novel therapeutic targets for intervention in 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.

Association of tumor necrosis factor-alpha-863C/A gene polymorphism with chronic obstructive pulmonary disease

The aim of this study was to investigate genetic effects on the pathogenesis of chronic obstructive pulmonary disease (COPD). The study was conducted as a prospective case-control study in a medical center in southern Taiwan. The patient group consisted of 145 male patients with smoking-related COPD and a control group of 139 resistant smokers from July 2004 to September 2009. We compared allele and genotype frequencies of three tag single nucleotide polymorphisms (SNP) of the TNF-alpha gene promoter region at -308, -863, and -1031 in all subjects. We also analyzed the influence of each genetic variant on pulmonary function parameters, body mass index (BMI), serum TNF-alpha levels, and outcomes among heavy smokers with or without COPD. COPD patients had a significantly lower A allele frequency (9.7 vs. 15.1%, OR = 0.6, p = 0.048, false discovery rate q = 0.144) and a significantly lower A carrier genotype frequency (19.3 vs. 30.2%, OR = 0.52, p = 0.042, q = 0.135) than resistant smokers. The -863 CA genotype was associated with a better FEV(1)/FVC ratio (79 vs. 71.5%, p = 0.034), and higher BMI (24.9 vs. 23.6 kg/m(2), p = 0.048). In addition, COPD patients with the -1031 C carrier genotype had higher serum TNF-alpha levels (20.9 vs. 16.2 pg/ml, p = 0.01). BMI (hazard ratio = 0.84, 95% CI = 0.74-0.96, p = 0.008) was the only independent predictor for mortality. The TNF-alpha -863 A allele may confer a degree of resistance to the susceptibility to and muscle wasting of COPD among heavy smokers.

TNF-alpha inhibitors in asthma and COPD: we must not throw the baby out with the bath water

Tumor necrosis factor (TNF)-alpha, a pleiotropic cytokine that exerts a variety of effects, such as growth promotion, growth inhibition, angiogenesis, cytotoxicity, inflammation, and immunomodulation, has been implicated in several inflammatory conditions. It plays a significant role in many inflammatory diseases of lungs. Given that there is significant literature supporting the pathobiologic role of TNF-alpha in asthma, mainly in severe refractory asthma, and COPD, TNF-alpha inhibitors (infliximab, golimumab and etanercept) are now regarded as the potential new medications in asthma and COPD management. The studies reported in literature indicate that TNF-alpha inhibitors are effective in a relatively small subgroup of patients with severe asthma, possibly defined by an increased TNF axis, but they seem to be ineffective in COPD, although an observational study demonstrated that TNF-alpha inhibitors were associated with a reduction in the rate of COPD hospitalisation among patients with COPD receiving these agents to treat their rheumatoid arthritis. These findings require a smart approach because there is still good reason to target TNF-alpha, perhaps in a more carefully selected patient group. TNF-alpha treatment should, therefore, not be thrown out, or abandoned. Indeed, since severe asthma and COPD are heterogeneous diseases that have characteristics that occur with different phenotypes that remained poorly characterized and little known about the underlying pathobiology contributing to them, it is likely that definition of these phenotypes and choice of the right outcome measure will allow us to understand which kind of patients can benefit from TNF-alpha inhibitors.

Impact of statins and ACE inhibitors on mortality after COPD exacerbations

Background

The purpose of our study was to examine the association of prior outpatient use of statins and angiotensin converting enzyme (ACE) inhibitors on mortality for subjects ≥ 65 years of age hospitalized with acute COPD exacerbations.

Methods

We conducted a retrospective national cohort study using Veterans Affairs administrative data including subjects ≥65 years of age hospitalized with a COPD exacerbation. Our primary analysis was a multilevel model with the dependent variable of 90-day mortality and hospital as a random effect, controlling for preexisting comorbid conditions, demographics, and other medications prescribed.

Results

We identified 11,212 subjects with a mean age of 74.0 years, 98% were male, and 12.4% of subjects died within 90-days of hospital presentation. In this cohort, 20.3% of subjects were using statins, 32.0% were using ACE inhibitors or angiotensin II receptor blockers (ARB). After adjusting for potential confounders, current statin use (odds ratio 0.51, 95% confidence interval 0.40–0.64) and ACE inhibitor/ARB use (0.55, 0.46–0.66) were significantly associated with decreased 90-day mortality.

Conclusion

Use of statins and ACE inhibitors prior to admission is associated with decreased mortality in subjects hospitalized with a COPD exacerbation. Randomized controlled trials are needed to examine whether the use of these medications are protective for those patients with COPD exacerbations.

Anti-TNF-alpha therapies in chronic obstructive pulmonary diseases

BACKGROUND

Chronic obstructive pulmonary disease (COPD) and asthma are chronic diseases in which inflammation of the airways leads to progressive transient airway obstruction and TNF-alpha plays an important pro-inflammatory role.

OBJECTIVE

To assess the plausibility of anti-TNF-alpha therapies playing an anti-inflammatory role in asthma and COPD.

METHODS

Scientific rationale of TNF-alpha targeting in asthma and COPD was assessed individually and the available data on the use of anti-TNF-alpha in each disease were reviewed.

RESULTS AND CONCLUSION

Anti-TNF-alpha therapies demonstrate different efficacies in asthma and COPD and further supportive preclinical and clinical data are needed, especially about subsets of certain diseases which could benefit the most from these therapies.

TNF alpha receptor genotype influences smoking-induced muscle-fibre-type shift and atrophy in mice

Systemic manifestations of chronic obstructive pulmonary disease (COPD) include muscle wasting, and tumour necrosis factor alpha (TNFalpha) could represent a major inducer of these processes. We studied skeletal muscle histology in a murine model of cigarette smoke (CS)-induced COPD, comparing mice with different TNFalpha receptor genotypes. Muscles from hind limbs of wild type (WT), TNFalpha receptor 1 knockout (TNF alpha R1KO) and TNF alpha R2KO mice were prepared and weighed. The lower body weight, which was observed in CS-exposed WT and TNF alpha R1KO mice, was paralleled by reduced weights of gastrocnemius and biceps femoris muscle. The gastrocnemius muscle was evaluated for muscle fibre apoptosis and atrophy, and fibre-type distribution. CS-induced apoptosis was observed in all genotypes, while a significant reduction of cross-sectional areas of myofibres was present only in TNF alpha R2KO mice. A CS-induced fibre-type shift from the IIa to the IIb phenotype was observed in WT mice, an increase of muscle-fibre-type IIx was noticed in CS-exposed TNF alpha R2KO mice. Our data suggest that the skeletal muscle manifestations associated with this murine COPD model are under complex regulation by both TNFalpha receptors, but that TNF alpha R2 may be the most important determinant for the outcome of CS-induced myofibre apoptosis.

Global burden of COPD: risk factors, prevalence, and future trends

Chronic obstructive pulmonary disease (COPD) continues to be an important cause of morbidity, mortality, and health-care costs worldwide. It is a global health issue, with cigarette smoking being an important risk factor universally; other factors, such as exposure to indoor and outdoor air pollution, occupational hazards, and infections, are also important. As the global population ages, the burden of COPD will increase in years to come. Prevalence estimates of the disorder show considerable variability across populations, suggesting that risk factors can affect populations differently. Other advances in our understanding of COPD are increased recognition of the importance of comorbid disease, identification of different COPD phenotypes, and understanding how factors other than lung function affect outcome in our patients. The challenge we will all face in the next few years will be implementation of cost-effective prevention and management strategies to stem the tide of this disease and its cost.

TNF-alpha antagonists and the prevention of hospitalisation for chronic obstructive pulmonary disease

BACKGROUND

TNF-alpha may be important in the pathogenesis of COPD. Consequently, the use of TNF-alpha antagonists has been advocated for its treatment.

METHODS

We conducted an observational study to evaluate the effectiveness of TNF-alpha antagonists in preventing COPD hospitalisations in a cohort of patients diagnosed with both RA and COPD identified from a health claims database. A nested case-control approach was used to match each case hospitalised to 10 controls on age and cohort entry date. Data on prescribed medications during the year prior to the index date were obtained. Rate ratios (RR) of COPD hospitalisation were estimated by conditional logistic regression, after adjustment for COPD severity and concomitant RA medication use.

RESULTS

The cohort included 15,771 subjects with both RA and COPD, of which 1205 were hospitalised for COPD during follow-up. The adjusted RR of COPD hospitalisation associated with the use of TNF-alpha antagonists was 0.62 (95% confidence interval (CI) 0.43-0.89). This rate reduction was due to etanercept (RR 0.49, 95% CI 0.29-0.82) but not infliximab (RR 0.95, 95% CI 0.59-1.52).

CONCLUSION

Our finding of a halving in the rate of COPD hospitalisation associated with the use of etanercept corroborates the potential importance of TNF-alpha in the pathogenesis of COPD. This study supports the initiation of randomised controlled trials of this TNF-alpha antagonist among COPD patients at high risk of severe exacerbations.

TNF polymorphisms modify endotoxin exposure-associated longitudinal lung function decline

OBJECTIVES

Endotoxin exposure induces airway inflammation, hyper-responsiveness and higher expression of tumour necrosis factor (TNF). This study was conducted to investigate whether TNF polymorphisms modify the effect of endotoxin exposure on chronic declines in lung function.

METHODS

Associations between TNF and LTA polymorphisms, endotoxin exposure and lung function were analysed in 263 cotton workers and 230 silk workers as a reference group, who were prospectively followed for 20 years. Multiple linear regression models were used to assess the association, with adjustment for smoking and other covariates.

RESULTS

Endotoxin exposure was associated with faster lung function decline among genotypes associated with higher TNF expression levels, with estimates of annual FEV1 change in relation to endotoxin exposure of -2.9 ml and -6.8 ml in the G/G and G/A+AA genotypes, respectively, for the TNF polymorphism; and -2.0 ml, -4.0 ml and -3.6 ml in A/A, A/G and G/G genotypes, respectively, for the LTA polymorphism. When joint effects of endotoxin exposure and smoking were considered, the effect modification of TNF and LTA polymorphisms was prominent in never smokers.

CONCLUSIONS

TNF and LTA polymorphisms may modify the association between occupational endotoxin exposure and longitudinal lung function decline, which was more clearly observed in never smokers.

The safety and efficacy of infliximab in moderate to severe chronic obstructive pulmonary disease

RATIONALE

Chronic obstructive pulmonary disease (COPD) is a progressive, smoking-related, inflammatory lung disease in which tumor necrosis factor-alpha is overexpressed and has been suggested to play a pathogenic role.

OBJECTIVES

To determine if infliximab, an anti-TNF-alpha antibody, results in clinical benefit and has an acceptable safety profile in patients with moderate to severe COPD.

METHODS

In a multicenter, randomized, double-blind, placebo-controlled, parallel-group, dose-finding study, subjects with moderate to severe COPD received infliximab (3 mg/kg [n = 78] or 5 mg/kg [n = 79]) or placebo (n = 77) at Weeks 0, 2, 6, 12, 18, and 24. Efficacy, health status, and safety were assessed through Week 44.

MEASUREMENTS AND MAIN RESULTS

Infliximab was generally well tolerated, but showed no treatment benefit as measured by the primary endpoint, Chronic Respiratory Questionnaire total score. Similarly, there was no change in secondary measures, including prebronchodilator FEV(1), 6-min walk distance, SF-36 physical score, transition dyspnea index, or moderate-to-severe COPD exacerbations. Post hoc analysis revealed that subjects who were younger or cachectic showed improvement in the 6-min walk distance. Malignancies were diagnosed during the study in 9 of 157 infliximab-treated subjects versus 1 of 77 placebo-treated subjects. No opportunistic infections were observed, and there were no differences in the occurrence of antibiotic-requiring infections, although the incidence of pneumonia was higher in infliximab-treated subjects. No infection-related mortality was observed. Higher proportions of infliximab-treated subjects discontinued the study agent due to adverse events (20-27%) than did placebo-treated subjects (9%).

CONCLUSIONS

Subjects with moderate to severe COPD did not benefit from treatment with infliximab. Although not statistically significant, more cases of cancer and pneumonia were observed in the infliximab-treated subjects. The impact of infliximab on malignancy risk in patients with COPD needs to be further elucidated.

Systemic inflammation in COPD: is genetic susceptibility a key factor?

COPD is a multicomponent disease characterized by abnormal inflammatory response of the lungs to noxious particles that is accompanied by systemic effects like weight loss, muscle wasting, reduced functional capacity and impaired health status. A persistent low-grade systemic inflammatory response reflected by enhanced levels of acute phase proteins like C-reactive protein (CRP) and pro-inflammatory cytokines such as tumor necrosis factor (TNF)-alpha, is present in part of the COPD population. The production of inflammatory proteins is partly genetically determined. Several studies have shown that polymorphisms within genes coding for these inflammatory mediators may modulate systemic inflammatory responses. Among all of these genes, the TNF family (TNF-alpha, lymphotoxin (LT)-alph and their receptors TNF-R55 and TNF-R75), interleukin (IL)-6 and CRP gene polymorphisms are the most prominent candidates. However, large carefully designed studies in well-characterized COPD cohorts are required to unravel the exact role of genetic background in the systemic component of this disease.

Tumour necrosis factor gene complex polymorphisms in chronic obstructive pulmonary disease

We aimed to examine the role of tumour necrosis factor gene complex polymorphisms in subjects with chronic obstructive pulmonary disease (COPD). We hypothesized that individuals possessing polymorphic variants associated with higher tumour necrosis factor (TNF) secretion would be more susceptible to and/or have more severe disease. Patients with COPD and population controls underwent detailed clinical phenotyping. Genotyping for the tumour necrosis factor-308 and the lymphotoxin alpha NcoI (LTalpha polymorphisms was carried out by 'blinded' laboratory staff. Three hundred and sixty one individuals (220 cases and 141 controls) were recruited. We showed an association between the LTalphaNcol polymorphism and forced vital capacity (FVC) in a population of older adults with and without COPD. The LTalphaNcol*2 allele was associated with poorer lung function, under a codominant model, with a fall in FVC (expressed as a percentage of its predicted value) of 3.7% for each copy of the LTalphaNcol*2 allele possessed (for FVC, regression coefficient (95% CI)=-3.73(-7.01 to -0.44), P=0.026; for FEV(1) regression coefficient=-3.56(-7.80 to 0.70), P=0.101. However, there was no difference in genotype distribution between the case and control populations. This study adds weight to the suggestion that the TNF gene complex is involved in physiological alterations (FVC) that may affect the development and severity of COPD. The absence of a significant association between the TNF gene-complex polymorphisms in this study does not rule out a modest effect of these polymorphisms on the risk of COPD, as much larger studies are needed to detect modest gene effects on binary disease endpoints.

Tumor Necrosis Factor Alpha and Pulmonary Function in Saskatchewan Grain Handlers

OBJECTIVE

The objective of this study was to estimate the contribution of lifestyle (cigarettes) and tumor necrosis factor (TNF) alpha polymorphisms at position 308 of the tumor necrosis factor alpha gene promotor (TNF-308*1/*2) to pulmonary function among grain handlers.

METHODS

Employed male grain handlers (157) provided occupational and respiratory symptom information, pulmonary function measurements, and DNA for genotyping.

RESULTS

The genotypes of 101 were TNF-308*1/*1, 47 were *1/*2, and nine were *2/*2. Current smokers whose genotype was *2/*2 or *1/*2 had lower values compared with other combinations of genotype and smoking status. Among *1/*1 homozygotes, current smokers had better percent of predicted forced expiratory volume in 1 second (P = 0.04) mean values than nonsmokers and better percent of predicted forced vital capacity than exsmokers (P = 0.017) or nonsmokers (P = 0.008).

CONCLUSIONS

These results indicate the complexity of determining which workers will develop acute and chronic adverse pulmonary conditions in response to exposure to grain dust and the toxins in cigarette smoke interacting with their genotype.

Association of IL8, CXCR2 and TNF-alpha polymorphisms and airway disease

Chronic obstructive pulmonary disease (COPD) is a disease characterised by inflammation of the peripheral airways involving many inflammatory cells and mediators. IL8 is an important inflammatory mediator that is responsible for the migration and activation of neutrophils. Cellular activity of IL8 is mediated by the receptor CXCR2, and transcription of IL8 is controlled by the cytokine tumour necrosis factor (TNFalpha). The aim of our study was to investigate the influence of single nucleotide polymorphisms in IL8, CXCR2 and TNF-alpha on lung function and respiratory symptoms in subjects from Melbourne, Australia. A total of 1,232 participants completed a detailed respiratory questionnaire, spirometry and measurement of gas transfer. Genotyping for the IL8 -251 T-->A, CXCR2 +785C-->T and TNF-alpha -308G-->A polymorphisms was performed using the tetra-primer ARMS-PCR method. The TNF-alpha A allele was associated with a reduced FEF(25-75) (P = 0.03). Inheritance of the CXCR2 T allele was associated with significantly higher diffusing capacity (P = 0.03) and FEF(25-75) (P = 0.02). No association with the IL8 -251 polymorphism was found. Our results suggest that TNF-alpha is associated with COPD-related phenotypes and the CXCR2 +785 SNP may be important in protecting against pulmonary inflammation. These genes may be important candidates in the modulation of the inflammatory response in the airways.

Biological targets for therapeutic interventions in COPD: clinical potential

COPD is a widespread inflammatory respiratory disorder characterized by a progressive, poorly reversible airflow limitation. Currently available therapies are mostly based on those used to treat asthma. However, such compounds are not able to effectively reduce the gradual functional deterioration, as well as the ongoing airway and lung inflammation occurring in COPD patients. Therefore, there is an urgent need to improve the efficacy of the existing drug classes and to develop new treatments, targeting the main cellular and molecular mechanisms underlying disease pathogenesis. These therapeutic strategies will be highlighted in the present review.

Genetics and the Dutch Hypothesis

BACKGROUND

Increasingly, molecular genetic techniques are being used to improve our understanding of a number of common late onset complex disorders, such as hypertension, Alzheimer's disease and noninsulin dependent diabetes mellitus. Molecular genetic approaches have the potential to yield new information about disease pathogenesis that may be of great importance for the development of future treatments.

AIMS

This review discusses the evidence for a genetic contribution to the development of chronic obstructive pulmonary disease (COPD) and specifically focuses on the hypothesis that asthma and COPD share some pathogenic mechanisms as originally proposed in 1960 in a theory that has since become known as the Dutch Hypothesis. In particular we will review the evidence from molecular genetics, both in support of and against the theory.

Pulmonary cachexia, systemic inflammatory profile, and the interleukin 1beta -511 single nucleotide polymorphism

BACKGROUND

Cachexia is common in chronic obstructive pulmonary disease (COPD) and is thought to be linked to an enhanced systemic inflammatory response.

OBJECTIVE

We investigated differences in the systemic inflammatory profile and polymorphisms in related inflammatory genes in COPD patients.

DESIGN

A cross-sectional study was performed in 99 patients with COPD (Global Initiative for Chronic Obstructive Lung Disease stages II-IV), who were stratified by cachexia based on fat-free mass index (FFMI; in kg/m2: <16 for men and <15 for women) and compared with healthy control subjects (HCs). Body composition was determined by bioelectrical impedance analysis. Plasma concentrations and gene polymorphisms of interleukin 1beta (IL-1beta -511), IL-6 (IL-6 -174), and the tumor necrosis factor system (TNF-alpha -308 and lymphotoxin-alpha +252) were determined. Plasma C-reactive protein, leptin, and urinary pseudouridine (as a marker of cellular protein breakdown) were measured.

RESULTS

Fat mass, leptin, and pseudouridine were significantly different (P < 0.001) between noncachectic patients (NCPs) and cachectic patients (CPs: n = 35); the systemic inflammatory cytokine profile was not. NCPs had a body compositional shift toward a lower fat-free mass and a higher fat mass compared with HCs. CPs and NCPs had a greater systemic inflammatory response (P < 0.05) than did HCs, as reflected in C-reactive protein, soluble TNF-R75, and IL-6 concentrations. The overall distribution of the IL-1beta -511 polymorphism was significantly different between the groups (P < 0.05).

CONCLUSIONS

In COPD patients, who are characterized by an elevated systemic inflammatory response, cachexia is not discriminatory for the extent of increase in inflammatory status. This study, however, indicates a potential influence of genetic predisposition on the cachexia process.

First Study of Infliximab Treatment in Patients with Chronic Obstructive Pulmonary Disease

RATIONALE

Tumor necrosis factor-alpha is believed to be important in the induction and maintenance of airway inflammation in chronic obstructive pulmonary disease.

OBJECTIVES

We aimed to evaluate the effect of the anti-tumor necrosis factor-alpha drug infliximab in patients with chronic obstructive pulmonary disease, with percentage of sputum neutrophils as the primary endpoint.

METHODS

We performed an exploratory single-center, double-blind, placebo-controlled, randomized, phase 2 trial in which 22 current smokers with mild-to-moderate chronic obstructive pulmonary disease participated. Fourteen patients received three infusions of infliximab (5 mg/kg) at Weeks 0, 2, and 6, and eight patients received placebo infusions. Sputum samples, respiratory symptoms, quality of life, exhaled nitric oxide, lung function parameters, bronchial hyperresponsiveness, resting energy expenditure, and side effects were evaluated.

MEASUREMENTS AND MAIN RESULTS

This study did not show a positive short-term effect of infliximab on airway inflammation, lung function, resting energy expenditure, or quality of life. Exhaled nitric oxide increased significantly at Day 2, Week 6, and Week 8 in patients receiving infliximab compared with those receiving placebo. Eight patients in the infliximab group (vs. none in the placebo group) reported increased coughing, but no serious adverse events or increase in respiratory infections were reported during 9 weeks of follow-up.

CONCLUSIONS

In this short-term study, no clinically beneficial effects of infliximab were observed, and there were no significant safety issues. Definite conclusions concerning the effectiveness of infliximab treatment in chronic obstructive pulmonary disease await additional studies, including those with a larger number of patients with more advanced disease.

Mediators of chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is a major and increasing global health problem that is now a leading cause of death. COPD is associated with a chronic inflammatory response, predominantly in small airways and lung parenchyma, which is characterized by increased numbers of macrophages, neutrophils, and T lymphocytes. The inflammatory mediators involved in COPD have not been clearly defined, in contrast to asthma, but it is now apparent that many lipid mediators, inflammatory peptides, reactive oxygen and nitrogen species, chemokines, cytokines, and growth factors are involved in orchestrating the complex inflammatory process that results in small airway fibrosis and alveolar destruction. Many proteases are also involved in the inflammatory process and are responsible for the destruction of elastin fibers in the lung parenchyma, which is the hallmark of emphysema. The identification of inflammatory mediators and understanding their interactions is important for the development of anti-inflammatory treatments for this important disease.