Tumor necrosis factor gene complex in COPD and disseminated bronchiectasis

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.

Genetic Distribution of the LTA +252 A>G and TNFA -308 G > A Polymorphisms in the Moroccan Population

Introduction: The LTA and TNFA genes encode key proinflammatory cytokines with diverse activities in the immune responses. Single nucleotide polymorphisms (SNPs) in the LTA rs909253 (+252 A > G) and TNFA rs1800629 (-308 G > A) genes have been associated with susceptibility to many complex diseases. The aim of this study was to assess the frequency for these two key polymorphisms in the Moroccan population. Materials and Methods: A total of 338 unrelated healthy Moroccan subjects were genotyped for the two alleles using a restriction fragment length polymorphism-polymerase chain reaction method. Results: The LTA (+252 A > G) and TNFA (-308 G > A) were the most common alleles with 67.9% and 74.8% frequencies, respectively. In addition to the linkage disequilibrium between the two SNPs, significant differences in allele frequencies were observed in Moroccan population compared with Mediterraneans, Europeans, Africans, South Americans, and Asians (p < 0.05). Finally, genetic proximities between Moroccan, European, and West African populations were found by means of the principal component analysis. Conclusion: The LTA +252 A>G and TNFA -308 G > A polymorphisms among Moroccan population follow the patterns commonly encountered in other Mediterranean, European, and African populations. The result of this study could contribute in developing a genetic database on the healthy Moroccan population.

Pathophysiology and Genetics of Bronchiectasis Unrelated to Cystic Fibrosis

Bronchiectasis is characterized by deregulated inflammatory response and recurrent bacterial infection resulting in progressive lung damage and an irreversible dilatation of bronchi and bronchioles. Generally accepted model of the development of bronchiectasis is the "vicious cycle hypothesis" that proposes compromising of the mucociliary clearance by an initial event, which leads to the infection of the respiratory tract followed by further impairment of mucociliary function, bacterial proliferation, and more inflammation. Bronchiectasis is a very common symptom in patients with cystic fibrosis (CF), while bronchiectasis unrelated to CF is heterogeneous pathology of unknown cause with a large number of potential contributory factors and poorly understood pathogenesis. It is presumed that bronchiectasis unrelated to CF is a multifactorial condition predisposed by genetic factors. Different molecules have been implicated in the onset and development of idiopathic bronchiectasis, as well as modulation of the disease severity and response to therapy. Most of these molecules are involved in the processes that contribute to the homeostasis of the lung tissue, especially mucociliary clearance, protease-antiprotease balance, and immunomodulation. Evaluation of the studies performed towards investigation of the role these molecules play in bronchiectasis identifies genetic variants that may be of potential importance for clinical management of the disease, and also of interest for future research efforts. This review focuses on the molecules with major roles in lung homeostasis and their involvement in bronchiectasis unrelated to CF.

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.

EPHX1 Y113H polymorphism is associated with increased risk of chronic obstructive pulmonary disease in Kazakhstan population

Chronic obstructive pulmonary disease (COPD) is a type of obstructive lung disease characterized by long term poor airflow which worsens over time. It is considered to be one of the top five chronic diseases of the world in terms of morbidity and mortality. Genetic variability has been found to contribute to the development of COPD. Although association between gene polymorphisms in EPHX1 and TNF-a genes and chronic obstructive pulmonary disease (COPD) have been found but till date no genetic association studies have been done in the COPD affected Kazakhstan population. The aim of the present work was to investigate the association between the Y113H polymorphism (rs1051740) in EPHX1 gene and -308G/A polymorphism (rs1800629) in TNF-a gene and COPD in Kazakhstan population. A case-control study was conducted in Astana and Akmola regions of Kazakhstan, involving 55 cases with COPD and 52 healthy individuals who served as the controls. The polymorphisms were determined using conventional PCR and Sanger sequencing method. Results show that for the EPHX1 gene Y113H polymorphism, the presence of an "C" allele (TC/CC genotype) was significantly overrepresented in the COPD patients compared to the controls. For the TNF-a gene -308G/A polymorphism, no significant difference was found between the two groups. Thus we found that, Y113H polymorphism in EPHX1 gene contributed to increased susceptibility to COPD in the Kazakhstan population.

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.

Genetic susceptibility

Why only 20% of smokers develop clinically relevant chronic obstructive pulmonary disease (COPD) was a puzzle for many years. Now, epidemiologic studies point clearly toward a large heritable component. The combination of genome-wide association studies and candidate gene analysis is helping to identify those genetic variants responsible for an individual's susceptibility to developing COPD. In this review, the current data implicating specific loci and genes in the pathogenesis of COPD are examined.

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.

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.

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.

Meta-analyses on suspected chronic obstructive pulmonary disease genes: a summary of 20 years' research

RATIONALE

Chronic obstructive pulmonary disease (COPD) is a complex disorder with high mortality worldwide. Studies on the role of candidate genes and their polymorphisms in COPD development have so far produced ambiguous results.

OBJECTIVES

The aim of this study was to reveal the role of COPD candidate genes using data collected in previous research.

METHODS

We performed meta-analyses on 20 polymorphisms in 12 genes, after searching the PubMed and Embase databases for publications on COPD. These genes involve three main pathways associated with COPD development: the inflammatory, protease-antiprotease balance, and antioxidant pathways.

MEASUREMENTS AND MAIN RESULTS

We obtained significant results for three TGFB1 polymorphisms, although these were based only on a few studies. The IL1RN VNTR polymorphism increases the risk for COPD (odds ratio [OR], 1.7; 95% confidence interval [CI], 1.09-2.65), whereas the TNFA -308 G/A polymorphism does so only in Asian populations (OR, 2.01; 95% CI, 1.21-3.31). The GSTP1 I105V polymorphism was protective for COPD in Asian populations only (OR, 0.69; 95% CI, 0.56-0.85).

CONCLUSIONS

These results demonstrate the importance of ethnicity in identifying specific COPD genes.

National Emphysema Treatment Trial state of the art: genetics of emphysema

Although a hereditary contribution to emphysema has been long suspected, severe alpha1-antitrypsin deficiency remains the only conclusively proven genetic risk factor for chronic obstructive pulmonary disease (COPD). Recently, genome-wide linkage analysis has led to the identification of two promising candidate genes for COPD: TGFB1 and SERPINE2. Like multiple other COPD candidate gene associations, even these positionally identified genes have not been universally replicated across all studies. Differences in phenotype definition may contribute to nonreplication in genetic studies of heterogeneous disorders such as COPD. The use of precisely measured phenotypes, including emphysema quantification on high-resolution chest computed tomography scans, has aided in the discovery of additional genes for clinically relevant COPD-related traits. The use of computed tomography scans to assess emphysema and airway disease as well as newer genetic technologies, including gene expression microarrays and genome-wide association studies, has great potential to detect novel genes affecting COPD susceptibility, severity, and response to treatment.

Development of a novel microarray methodology for the study of SNPs in the promoter region of the TNF-α gene—Their association with obstructive pulmonary disease in Greek patients

OBJECTIVES

Polymorphisms in promoter region of TNF-alpha gene were shown to interfere with the transcriptional activity of the gene resulting in the production of different levels of TNF-alpha product suggesting their involvement in susceptibility or severity of many inflammatory diseases. We set up a case-control study consisting of 117 COPD (Chronic Obstructive Pulmonary Disease), 62 DB (bronchiectasis) patients and two control groups (109 smokers without COPD-healthy smokers control group and 212 general population subjects) to evaluate involvement of TNF-alpha gene polymorphisms in the abovementioned diseases in a homogeneous population.

METHODS

The novel methodology of the NanoChip Molecular Biology Workstation (MBW Nanogen http://www.nanogen.com) was employed to genotype the 5 promoter SNPs.

RESULTS AND CONCLUSIONS

Genotype frequencies of the 5 SNPs showed no significant difference between the COPD and DB patient groups and the healthy smokers group. Statistical difference (p=0.043) was only revealed between the haplotype frequencies in COPD patients compared to the general population control group. The NanoChip MBW is an accurate method for SNP screening.

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.

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.

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.

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.

Tumor necrosis factor-alpha gene promoter polymorphism is not associated with smoking-related COPD in Thailand

OBJECTIVE

Susceptibility to COPD is, in part, genetically determined. Tumour necrosis factor (TNF)-alpha gene promoter polymorphisms have been investigated in different populations with inconsistent results. This study aimed to determine the genetic predisposition in Thai smoking-related COPD patients.

METHODOLOGY

The polymorphism at position -308 of the TNF-alpha gene promoter was examined in 57 patients with smoking-related COPD, 67 smoker control subjects, and 116 control anonymous blood donors. Genomic DNA from peripheral blood lymphocytes was used for genotypic analysis by polymerase chain reaction with sequence specific primers.

RESULTS

TNF-alpha-308*2 allele frequency was not significantly different between the population control subjects and the smoking-related COPD patients (4.7% vs. 7.9%, P= 0.14). This allele frequency was also not significantly different between smokers with and without COPD (7.9% vs. 7.5%, P= 0.46).

CONCLUSIONS

Although it has been speculated that TNF-alpha might have a causal relationship with COPD, a role for the TNF-alpha gene promoter polymorphism in disease development in Thailand was not demonstrated.

Polymorphisms of TNFα, IL1β, and IL1RN genes in chronic obstructive pulmonary disease

It is recognized that genetic factors play a role in the susceptibility to COPD. COPD is characterized by airflow limitation. Chronic inflammation causes small airway disease and parenchymal destruction, leading to the airflow limitation. Polymorphisms in pro-inflammatory cytokine genes may confer a risk for the development of COPD. A case-control association study was performed in Japanese population (88 COPD patients and 61 controls) and Egyptian population (106 patients and 72 controls). Genotype and allele frequencies of the TNFalpha -308 G/A and +489 G/A polymorphisms, the IL1beta -511 C/T, -31 T/C, and +3954 C/T polymorphisms, and a VNTR polymorphism in intron 2 of the IL1RN gene were investigated. In addition, pairwise haplotype frequencies were analyzed. When studied independently, none of the polymorphisms were associated with the development of COPD in both populations. However, in the Egyptian population, the distributions of the haplotype (IL1beta -31 T/C : IL1beta +3954 C/T) were significantly different between the COPD patients and the controls (p(corr)=0.0037). Our findings suggest that this haplotype within the IL1beta gene may be involved in the pathogenesis of COPD and that the genetic factors of COPD susceptibility might be different between different populations.

ROS in the local and systemic pathogenesis of COPD

An imbalance between oxidants and antioxidants is proposed in the pathogenesis of COPD. Potential alterations responsible for an imbalance in oxidant production and intra- and extracellular antioxidant defense systems are discussed with respect to COPD-related changes in the pulmonary compartment. In line with the current view of COPD as a disease with multiple systemic consequences, there is increasing evidence that imbalances in the redox milieu extend beyond the diseased lung in COPD patients. Skeletal muscle dysfunction is often observed in COPD and may result from imbalances in the redox environment of skeletal muscle. Potential triggers of oxidative stress in the muscle compartment include inflammation and hypoxia, and local sources of reactive oxygen and nitrogen species are discussed, as well the mechanisms by which skeletal muscle trophical state, contractility and fatigability may be affected by oxidative stress, resulting in skeletal muscle dysfunction.

Effect of TNF and LTA polymorphisms on biological markers of response to oxidative stimuli in coal miners: a model of gene-environment interaction. Tumour necrosis factor and lymphotoxin alpha

INTRODUCTION

Interaction between genetic background and oxidative environmental stimuli in the pathogenesis of human lung disease has been largely unexplored.

METHODS

A prospective epidemiological study was undertaken in 253 coal miners. Intermediate quantitative phenotypes of response to oxidant exposure, including erythrocyte glutathione peroxidase (GSH-Px) and catalase activities, were studied. Oxidant exposures studied were smoking habits and cumulative dust exposure assessed by job history and ambient measures. Disease phenotypes included subclinical computed tomography score at the first survey and x ray profusion grades twice, five years apart, to assess established coal workers' pneumoconiosis (CWP). Miners were genotyped for common functional polymorphisms in the gene for tumour necrosis factor alpha (TNF) and lymphotoxin alpha (LTA), two proinflammatory cytokines that have been implicated in the pathogenesis of chronic lung diseases.

RESULTS

Regarding gene-environment interaction on intermediate phenotypes, results showed interaction of a promoter polymorphism at the -308 position in TNF with occupational exposure on erythrocyte GSH-Px activity with a significant association in those with high exposure (p=0.003), whereas no association was observed among those with low exposure (interaction p=0.06). Regarding gene intermediate phenotype interaction on clinical outcome, results showed an association of CWP prevalence with an NcoI polymorphism in LTA in those with low catalase activity (p=0.05), whereas no association was observed in those with high activity (interaction p=0.03). No other significant association was observed.

CONCLUSION

The results suggest that interactions of genetic background with environmental exposure and intermediate response phenotypes are important components in the pathogenesis of CWP.

Tumor necrosis factor-alpha +489G/A gene polymorphism is associated with chronic obstructive pulmonary disease

BACKGROUND

Chronic obstructive pulmonary disease (COPD) is characterized by a chronic inflammatory process, in which the pro-inflammatory cytokine Tumor Necrosis Factor (TNF)-alpha is considered to play a role. In the present study the putative involvement of TNF-alpha gene polymorphisms in pathogenesis of COPD was studied by analysis of four TNF-alpha gene polymorphisms in a Caucasian COPD population.

METHODS

TNF-alpha gene polymorphisms at positions -376G/A, -308G/A, -238G/A, and +489G/A were examined in 169 Dutch COPD patients, who had a mean forced expiratory volume in one second (FEV1) of 37 +/- 13%, and compared with a Dutch population control group of 358 subjects.

RESULTS

The data showed that the TNF-alpha +489G/A genotype frequency tended to be different in COPD patients as compared to population controls, which was due to an enhanced frequency of the GA genotype. In line herewith, carriership of the minor allele was associated with enhanced risk of development of COPD (odds ratio = 1.9, p = 0.009). The other TNF-alpha gene polymorphisms studied revealed no discrimination between patients and controls. No differences in the examined four TNF-alpha polymorphisms were found between subtypes of COPD, which were stratified for the presence of radiological emphysema. However, comparison of the COPD subtypes with controls showed a significant difference in the TNF-alpha +489G/A genotype in patients without radiological emphysema (chi2-test: p < 0.025 [Bonferroni adjusted]), while no differences between COPD patients with radiological emphysema and controls were observed.

CONCLUSION

Based on the reported data, it is concluded that COPD, and especially a subgroup of COPD patients without radiological emphysema, is associated with TNF-alpha +489G/A gene polymorphism.

Polymorphisms for interleukin-4 (IL-4) -590 promoter, IL-4 intron3, and tumor necrosis factor alpha -308 promoter: non-association with endometriosis

Interleukin-4 (IL-4) is a cytokine with anti-inflammatory properties. Tumor necrosis factor alpha (TNF-alpha), a pluripotent proinflammatory cytokine, plays an important role in the process of numerous inflammatory and autoimmune diseases. We aimed to investigate whether gene polymorphisms for the IL-4 -590 promoter, IL-4 intron3 and TNFalpha -308 promoter could be used as markers of susceptibility in endometriosis. The subjects, 226 premenopausal Taiwan Chinese women with surgically diagnosed endometriosis and nonendometriosis, were divided into two groups: 1) endometriosis (n = 120) and 2) nonendometriosis (n = 106). Polymorphisms for the IL-4 -590 promoter, IL-4 intron3, and TNFalpha -308 G-to-A promoter were detected by polymerase chain reaction (PCR). Genotypes and allelic frequencies for these gene polymorphisms in both groups were compared. We observed no significant differences in genotype distribution and allele frequency of the IL-4 -590 promoter, IL-4 intron3, and TNFalpha gene polymorphism between both groups. The proportions of the -590*C homozygote/heterozygote/-590* T homozygote for the IL-4 promoter in both groups were 1.6/31.6/66.6% in group 1, and 5.8/33.0/61.2% in group 2. The proportions of the RP1 homozygote/heterozygote/RP2 homozygote for IL-4 intron3 in both groups were 62.5/34.1/2.5% (group 1), and 64.1/32.0/3.9% (group 2). The proportions of -308*A homozygote/heterozygote/-308*G homozygote for the TNFalpha promoter in both groups were 7.5/20.8/71.7% (group 1), and 7.5/17/75.5% (group 2). We concluded that there is no association between endometriosis and the IL-4 and TNFalpha gene polymorphisms. The IL-4 -590 promoter, IL-4 intron3, and TNFalpha -308 G-to-A polymorphisms are not useful markers for predicting susceptibility to endometriosis.

Pathogenesis and pathology of COPD

Chronic obstructive pulmonary disease (COPD) is characterized by airflow limitation. Since flow is the result of a driving pressure that promotes flow and of an opposing resistance that contradicts it, the reduction in flow observed in COPD has two main components: increased resistance, which is due to airway obstruction, and a loss of the elastic recoil pressure of the lung, which is due to parenchymal destruction. Although it has long been known that the major site of increased resistance in COPD is the peripheral airways, recent studies have shown that central airways are involved in the disease as well. The purpose of this review is to describe the major structural and cellular changes present in peripheral airways, central airways and lung parenchyma of patients with COPD, and to underline the possible mechanisms contributing to airflow limitation in these subjects.

The genetics of chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is a significant cause of global morbidity and mortality. Previous studies have shown that COPD aggregates in families, suggesting a genetic predisposition to airflow obstruction. Many candidate genes have been assessed, but the data are often conflicting. We review the genetic factors that predispose smokers to COPD and highlight the future role of genomic scans in identifying novel susceptibility genes.

The genetics of chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is a significant cause of global morbidity and mortality. Previous studies have shown that COPD aggregates in families, suggesting a genetic predisposition to airflow obstruction. Many candidate genes have been assessed, but the data are often conflicting. We review the genetic factors that predispose smokers to COPD and highlight the future role of genomic scans in identifying novel susceptibility genes.