Associations of IL6 polymorphisms with lung function decline and COPD

Increased cytokines response in patients with tuberculosis complicated with chronic obstructive pulmonary disease

Objectives

To explore the change and its significance of cytokines in patients with pulmonary tuberculosis complicated with COPD.

Methods

The immune function of 152 cases of pulmonary tuberculosis with COPD was detected to compare with 150 cases of patients with pulmonary tuberculosis, 157 cases of patients with COPD and 50 cases of healthy volunteers who were in the hospital during the same period. T lymphocyte cell population in peripheral blood was detected by flow cytometry. The serum levels of sIL-2R, IL-6, IFN-γ, TNF-α were measured using ELISA.

Results

The percentage of CD4+ T cells in TB patients with or without COPD and COPD patients without TB was significantly lower than that in control group. The percentage of CD4+ T cells in patients with TB and COPD was significantly lower than that in the non-COPD TB patients. The percentage of CD8+ T cells was higher in the TB patients group than that in control group. The CD4+/CD8+ ratio in the TB patients group was significantly lower than that in control group. The concentrations of sIL-2R, IL-6, TNF-α, IFN-γ in TB patients with or without COPD and COPD patients without TB were significantly higher than those in control group. In addition, sIL-2R, IL-6, TNF-α concentrations in the patients with TB and COPD were higher than those in the non-COPD TB patients. The concentrations of sIL-2R, IL-6, TNF-α, IFN-γ in COPD patients with TB were significantly higher than those in COPD patients without TB. There was a significant negative correlation between serum levels of TNF-α, IL-6 and FEV1 (%, predicted) in COPD without TB group.

Conclusions

The patients with pulmonary tuberculosis complicated with COPD were impaired in cellular immunity, and its extent of immune impairment is more serious than those of the patients with pulmonary tuberculosis and the patients with COPD.

Monoclonal antibodies for asthma and chronic obstructive pulmonary disease

INTRODUCTION

In asthma and chronic obstructive pulmonary disease (COPD), the inflammation in the airways cannot always be controlled with conventional therapies, such as inhaled corticosteroids. Addition of more specific anti-inflammatory therapies, such as monoclonal antibodies, against inflammation pathways might improve the disease outcome.

AREAS COVERED

This review individually discusses the major inflammation pathways and their potential blocking monoclonal antibodies in asthma and COPD.

EXPERT OPINION

The current use of omalizumab in asthma provides a good example on the potential therapeutic role of monoclonal antibodies in both asthma and COPD. There are many other monoclonal antibodies which are currently investigated as possible therapies in these diseases. The identification of the disease subsets in which such antibodies might exert the maximum benefit opens the door for personalized medicine and for targeted biological therapy in asthma and COPD.

Comparison of the anti-inflammatory effects of Cilomilast, Budesonide and a p38 Mitogen activated protein kinase inhibitor in COPD lung tissue macrophages

Chronic Obstructive Pulmonary Disease (COPD) is a disease characterized by a largely irreversible airflow obstruction and a persistent, excessive inflammatory response. Alveolar macrophages (AMs) are increased in the lungs of COPD patients, and act as orchestrators of the inflammatory response, releasing a range of mediators to coordinate recruitment and activation of leukocytes. Attempts to treat the inflammatory component of COPD with anti-inflammatory drugs such as steroids has met with limited success. In this study, we compared the ability of the phosphodiesterase IV (PDEIV) inhibitor Cilomilast, the steroid Budesonide, and the p38 mitogen activated protein kinase inhibitor BIRB-796 to inhibit tumour necrosis factor alpha (TNFα) and interleukin 6 (IL-6) releases from AMs isolated from COPD lung transplant tissue. All studies were carried out with appropriate ethical approval and written, informed consent was obtained from each subject. Cilomilast had little effect on cytokine release from AMs. There was considerable variability in the responsiveness of AMs to Budesonide, with a subset of AMs responding poorly to Budesonide. BIRB-796 inhibited TNFα release from all AM donors, including those that responded poorly to steroids. Treatment with BIRB-796 and Budesonide together gave an additive decrease in TNFa release. These results suggest that a p38 inhibitor may provide advantages over existing anti-inflammatory treatments for COPD, either as an add-on to existing therapy, or to treat patients who respond poorly to steroids.

Genome-wide association analysis of blood biomarkers in chronic obstructive pulmonary disease

RATIONALE

A genome-wide association study (GWAS) for circulating chronic obstructive pulmonary disease (COPD) biomarkers could identify genetic determinants of biomarker levels and COPD susceptibility.

OBJECTIVES

To identify genetic variants of circulating protein biomarkers and novel genetic determinants of COPD.

METHODS

GWAS was performed for two pneumoproteins, Clara cell secretory protein (CC16) and surfactant protein D (SP-D), and five systemic inflammatory markers (C-reactive protein, fibrinogen, IL-6, IL-8, and tumor necrosis factor-α) in 1,951 subjects with COPD. For genome-wide significant single nucleotide polymorphisms (SNPs) (P < 1 × 10(-8)), association with COPD susceptibility was tested in 2,939 cases with COPD and 1,380 smoking control subjects. The association of candidate SNPs with mRNA expression in induced sputum was also elucidated.

MEASUREMENTS AND MAIN RESULTS

Genome-wide significant susceptibility loci affecting biomarker levels were found only for the two pneumoproteins. Two discrete loci affecting CC16, one region near the CC16 coding gene (SCGB1A1) on chromosome 11 and another locus approximately 25 Mb away from SCGB1A1, were identified, whereas multiple SNPs on chromosomes 6 and 16, in addition to SNPs near SFTPD, had genome-wide significant associations with SP-D levels. Several SNPs affecting circulating CC16 levels were significantly associated with sputum mRNA expression of SCGB1A1 (P = 0.009-0.03). Several SNPs highly associated with CC16 or SP-D levels were nominally associated with COPD in a collaborative GWAS (P = 0.001-0.049), although these COPD associations were not replicated in two additional cohorts.

CONCLUSIONS

Distant genetic loci and biomarker-coding genes affect circulating levels of COPD-related pneumoproteins. A subset of these protein quantitative trait loci may influence their gene expression in the lung and/or COPD susceptibility. Clinical trial registered with www.clinicaltrials.gov (NCT 00292552).

Chronic obstructive pulmonary disease and glucose metabolism: a bitter sweet symphony

Chronic obstructive pulmonary disease, metabolic syndrome and diabetes mellitus are common and underdiagnosed medical conditions. It was predicted that chronic obstructive pulmonary disease will be the third leading cause of death worldwide by 2020. The healthcare burden of this disease is even greater if we consider the significant impact of chronic obstructive pulmonary disease on the cardiovascular morbidity and mortality. Chronic obstructive pulmonary disease may be considered as a novel risk factor for new onset type 2 diabetes mellitus via multiple pathophysiological alterations such as: inflammation and oxidative stress, insulin resistance, weight gain and alterations in metabolism of adipokines. On the other hand, diabetes may act as an independent factor, negatively affecting pulmonary structure and function. Diabetes is associated with an increased risk of pulmonary infections, disease exacerbations and worsened COPD outcomes. On the top of that, coexistent OSA may increase the risk for type 2 DM in some individuals. The current scientific data necessitate a greater outlook on chronic obstructive pulmonary disease and chronic obstructive pulmonary disease may be viewed as a risk factor for the new onset type 2 diabetes mellitus. Conversely, both types of diabetes mellitus should be viewed as strong contributing factors for the development of obstructive lung disease. Such approach can potentially improve the outcomes and medical control for both conditions, and, thus, decrease the healthcare burden of these major medical problems.

Role of IL-6 in asthma and other inflammatory pulmonary diseases

The incidence and severity of chronic lung diseases is growing and affects between 100 and 150 million people worldwide and is associated with a significant rate of mortality. Unfortunately, the initial cause that triggers most chronic lung diseases remains unknown and current available therapies only ameliorate, but do not cure the disease. Thus, there is a need for identification of new targets and development of novel therapies especially for those most severely affected. IL-6, like other inflammatory cytokines, has been shown to be elevated in different lung diseases, but it was considered a byproduct of ongoing inflammation in the lung. However, recent studies support a dissociation of IL-6 from inflammation in the lung and suggest that this cytokine plays an active role in pathogenesis of asthma and, in all likelihood, COPD. IL-6 may therefore be a germane target for treatment of these and other chronic lung disease. Here, we provide an overview of the studies in mouse models and human patients that provide support for the involvement of IL-6 in lung diseases.

Establishment of an optimized PCR method using sequence-specific primers for screening multiple gene polymorphisms simultaneously

The present study aimed to explore the factors that affect polymerase chain reaction using sequence-specific primers (PCR-SSP) and to establish an optimized PCR-SSP method for detecting multiple gene polymorphisms simultaneously. The amplification system parameters, including the concentrations of Mg2+, dNTPs, pfu Taq, primers and control primers, were optimized using the designed PCR-SSP reactions. The resulting optimized reaction system was used to determine the melting temperature of the genomic DNA and the cycling parameters. The optimized PCR-SSP method was used to analyze the polymorphisms of the following genes: mutations -308A/G and -238G/A in TNF-α, -174G/C in IL-6 and C/T mutation at exon 188 of CYP2D6 *10B. The PCR-SSP amplification system was optimized; in a 20 µl reaction system, the quantities of Mg2+, dNTPs, pfu Taq, primers, control primers and genomic DNA were 3.25 µM, 0.5 mM, 2.5 units, 0.5 µM, 0.2 µM and 0.15 µg, respectively. The cycling system comprised 5 start cycles and took 15 min to melt a genomic DNA sample using a touchdown protocol. The optimized PCR-SSP is suitable for polymorphism analysis of polygenic SNPs in large genomic DNA samples and a number of different genes.

Functional polymorphisms of CHRNA3 predict risks of chronic obstructive pulmonary disease and lung cancer in Chinese

Recently, several genome-wide association studies (GWAS) have identified many susceptible single nucleotide polymorphisms (SNPs) for chronic obstructive pulmonary disease (COPD) and lung cancer which are two closely related diseases. Among those SNPs, some of them are shared by both the diseases, reflecting there is possible genetic similarity between the diseases. Here we tested the hypothesis that whether those shared SNPs are common predictor for risks or prognosis of COPD and lung cancer. Two SNPs (rs6495309 and rs1051730) located in nicotinic acetylcholine receptor alpha 3 (CHRNA3) gene were genotyped in 1511 patients with COPD, 1559 lung cancer cases and 1677 controls in southern and eastern Chinese populations. We found that the rs6495309CC and rs6495309CT/CC variant genotypes were associated with increased risks of COPD (OR = 1.32, 95% C.I. = 1.14–1.54) and lung cancer (OR = 1.57; 95% CI = 1.31–1.87), respectively. The rs6495309CC genotype contributed to more rapid decline of annual Forced expiratory volume in one second (FEV1) in both COPD cases and controls (P<0.05), and it was associated with advanced stages of COPD (P = 0.033); the rs6495309CT/CC genotypes conferred a poor survival for lung cancer (HR = 1.41, 95%CI = 1.13–1.75). The luciferase assays further showed that nicotine and other tobacco chemicals had diverse effects on the luciferase activity of the rs6495309C or T alleles. However, none of these effects were found for another SNP, rs1051730G>A. The data show a statistical association and suggest biological plausibility that the rs6495309T>C polymorphism contributed to increased risks and poor prognosis of both COPD and lung cancer.

Functional characterization of the matrix metalloproteinase-1 cigarette smoke-responsive region and association with the lung health study

BACKGROUND

Prior studies have demonstrated that the distal 1.5 kb of the MMP-1 promoter is fundamental in directing the induction of the MMP-1 gene by cigarette smoke.

METHODS

To characterize the genetic variants in the MMP-1 cigarette smoke-responsive element, deep re-sequencing of this element was performed on DNA samples from participants in the Lung Health Study. Furthermore, evidence of Sp1 binding to the MMP-1 promoter was assessed using chromatin immunoprecipitation assays and the influence of cigarette smoke exposure on this interaction was evaluated in cultured human small airway epithelial cells.

RESULTS

Ten polymorphisms (four novel) were detected in the cigarette smoke-responsive element. Chromatin immunoprecipitation assays to assess the protein-DNA interactions at Sp1 sites in the MMP-1 promoter showed increased binding to the Sp1 sites in the cigarette smoke-responsive element in small airway epithelial cells treated with cigarette smoke extract. In contrast, a Sp1 site outside of the element exhibited the opposite effect. None of the polymorphisms were more prevalent in the fast decliners versus the slow decliners (fast decliners = mean -4.14% decline in FEV1% predicted per year vs. decline in FEV1% predicted per year).

CONCLUSIONS

Sequencing analyses identified four novel polymorphisms within the cigarette smoke-responsive element of the MMP-1 promoter. This study identifies functional activity within the cigarette smoke-responsive element that is influenced by cigarette smoke and examines this region of the promoter within a small patient population.

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.

Autoreactive T Cells in Human Smokers is Predictive of Clinical Outcome

Cross-sectional studies have suggested a role for activation of adaptive immunity in smokers with emphysema, but the clinical application of these findings has not been explored. Here we examined the utility of detecting autoreactive T cells as a screening tool for emphysema in an at-risk population of smokers. We followed 156 former and current (ever)-smokers for 2 years to assess whether peripheral blood CD4 T cell cytokine responses to lung elastin fragments (EFs) could discriminate between those with and without emphysema, and to evaluate the relevance of autoreactive T cells to predict changes during follow-up in lung physiological parameters. Volunteers underwent baseline complete phenotypic assessment with pulmonary function tests, quantitative chest CT, yearly 6-min walk distance (6MWD) testing, and annual measurement of CD4 T cell cytokine responses to EFs. The areas under the receiver operating characteristic curve to predict emphysema for interferon gamma (IFN-γ), and interleukin 6 (IL-6) responses to EFs were 0.81 (95% CI of 0.74-0.88) and 0.79 (95% CI of 0.72-0.86) respectively. We developed a dual cytokine enzyme-linked immunocell spot assay, the γ-6 Spot, using CD4 T cell IFN-γ and IL-6 responses and found that it discriminated emphysema with 90% sensitivity. After adjusting for potential confounders, the presence of autoreactive T cells was predictive of a decrease in 6MWD over 2 years (decline in 6MWD, -19 m per fold change in IFN-γ; P = 0.026, and -26 m per fold change in IL-6; P = 0.003). In support of the human association studies, we cloned CD4 T cells with characteristic T helper (Th)1 and Th17 responses to EFs in the peripheral blood of ever-smokers with emphysema, confirming antigenicity of lung elastin in this population. These findings collectively suggest that the EF-specific autoreactive CD4 T cell assay, γ-6 Spot, could provide a non-invasive diagnostic tool with potential application to large-scale screening to discriminate emphysema in ever-smokers, and predict early relevant physiological outcomes in those at risk.

Deregulated Stat3 signaling dissociates pulmonary inflammation from emphysema in gp130 mutant mice

Interleukin (IL)-6 is a potent immunomodulatory cytokine that is associated with emphysema, a major component of chronic obstructive pulmonary disease (COPD). IL-6 signaling via the gp130 coreceptor is coupled to multiple signaling pathways, especially the latent transcription factor signal transducer and activator of transcription (Stat)3. However, the pathological role of endogenous gp130-dependent Stat3 activation in emphysema is ill defined. To elucidate the role of the IL-6/gp130/Stat3 signaling axis in the cellular and molecular pathogenesis of emphysema, we employed a genetic complementation strategy using emphysematous gp130F/F mice displaying hyperactivation of endogenous Stat3 that were interbred with mice to impede Stat3 activity. Resected human lung tissue from patients with COPD and COPD-free individuals was also evaluated by immunohistochemistry. Genetic reduction of Stat3 hyperactivity in gp130F/F: Stat3 −/+ mice prevented lung inflammation and excessive protease activity; however, emphysema still developed. In support of these findings, Stat3 activation levels in human lung tissue correlated with the extent of pulmonary inflammation but not airflow obstruction in COPD. Furthermore, COPD lung tissue displayed increased levels of IL-6 and apoptotic alveolar cells, supporting our previous observation that increased endogenous IL-6 expression in the lungs of gp130F/F mice contributes to emphysema by promoting alveolar cell apoptosis. Collectively, our data suggest that IL-6 promotes emphysema via upregulation of Stat3-independent apoptosis, whereas IL-6 induction of lung inflammation occurs via Stat3. We propose that while discrete targeting of Stat3 may alleviate pulmonary inflammation, global targeting of IL-6 potentially represents a therapeutically advantageous approach to combat COPD phenotypes where emphysema predominates.

Single nucleotide polymorphisms as susceptibility, prognostic, and therapeutic markers of nonsmall cell lung cancer

Lung cancer is a major public health problem throughout the world. Among the most frequent cancer types (prostate, breast, colorectal, stomach, lung), lung cancer is the leading cause of cancer-related deaths worldwide. Among the two major subtypes of small cell lung cancer and nonsmall cell lung cancer (NSCLC), 85% of tumors belong to the NSCLC histological types. Small cell lung cancer is associated with the shortest survival time. Although tobacco smoking has been recognized as the major risk factor for lung cancer, there is a great interindividual and interethnic difference in risk of developing lung cancer given exposure to similar environmental and lifestyle factors. This may indicate that in addition to chemical and environmental factors, genetic variations in the genome may contribute to risk modification. A common type of genetic variation in the genome, known as single nucleotide polymorphism, has been found to be associated with susceptibility to lung cancer. Interestingly, many of these polymorphisms are found in the genes that regulate major pathways of carcinogen metabolism (cytochrome P450 genes), detoxification (glutathione S-transferases), adduct removal (DNA repair genes), cell growth/apoptosis (TP53/MDM2), the immune system (cytokines/chemokines), and membrane receptors (nicotinic acetylcholine and dopaminergic receptors). Some of these polymorphisms have been shown to alter the level of mRNA, and protein structure and function. In addition to being susceptibility markers, several of these polymorphisms are emerging to be important for response to chemotherapy/radiotherapy and survival of patients. Therefore, it is hypothesized that single nucleotide polymorphisms will be valuable genetic markers in individual-based prognosis and therapy in future. Here we will review some of the most important single nucleotide polymorphisms in the metabolic pathways that may modulate susceptibility, prognosis, and therapy in NSCLC.

Genetics of COPD

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

Effect of gene environment interactions on lung function and cardiovascular disease in COPD

Background:

The objective of this study was to determine if gene-environment interactions between cigarette smoking and interleukin-6 (IL6), interferon-γ (IFNG), interleukin-1β (IL1B), or interleukin-1 receptor antagonist (IL1RN) single nucleotide polymorphisms are associated with lung function decline and cardiovascular disease in chronic obstructive pulmonary disease (COPD).

Methods:

Single nucleotide polymorphisms (SNPs) in IL6, IFNG, IL1B, and IL1RN were genotyped in the Lung Health Study and correlated with rate of decline of forced expiratory volume in 1 second (FEV₁) over 5 years, baseline FEV₁, serum protein levels, cardiovascular disease, and interactions with smoking.

Results:

The IL6 rs2069825 single nucleotide polymorphism was associated with the rate of decline of prebronchodilator FEV₁ (P = 0.049), and was found to have a significant interaction (P = 0.004) with mean number of cigarettes smoked per day. There was also a significant interaction of IFNG rs2069727 with smoking on prebronchodilator (P = 0.008) and postbronchodilator (P =0.01) FEV_1. The IL6 polymorphism was also associated with cardiovascular disease in heterozygous individuals (P = 0.044), and was found to have a significant interaction with smoking (P = 0.024). None of the genetic variants were associated with their respective serum protein levels.

Conclusion:

The results suggest interactions of IL6 rs2069825 and IFNG rs2069727 single nucleotide polymorphisms with cigarette smoking on measures of lung function. The IL6 rs2069825 single nucleotide polymorphism also interacted with smoking to affect the risk of cardiovascular disease in COPD patients.

The CRP genotype, serum levels and lung function in men: the Caerphilly Prospective Study

Systemic CRP (C-reactive protein) has been associated with impaired lung function. A causal relationship would increase the value of CRP as both a diagnostic and therapeutic tool. We assessed the association between lung function parameters, circulating CRP and CRP polymorphisms using Mendelian randomization in efforts to attribute causality to known associations. Spirometric parameters of FEV1 (forced expiratory volume in 1 s) and FVC (forced vital capacity) were determined in 2173 men participating in the Caerphilly Prospective Study. Lung function measures on 1021 participants were available at follow-up (mean, 16.8 years later). Serum CRP levels were measured at baseline, and three CRP polymorphisms were analysed. Haplotype analysis was performed. Serum CRP levels at baseline were inversely associated with contemporaneous FEV1 and FVC as well as at follow-up (P<0.001) even after adjustment for conventional confounders. Serum CRP was associated with FEV1 decline (P=0.04). All three CRP polymorphisms (rs1800947, rs1130864 and rs1205) predicted serum CRP; however, there were no clear associations of the polymorphisms or haplotypes with lung function or with lung function decline. In conclusion, serum CRP was associated with lung function cross-sectionally; however, CRP polymorphisms were not associated with lung function or decline, suggesting that the CRP-lung function relationship is due to reverse causality, an unmeasured confounding factor or only has a modest causal effect.

Age-induced augmentation of p38 MAPK phosphorylation in mouse lung

The p38 mitogen-activated protein kinase (p38 MAPK) pathway is a key regulator of pro-inflammatory cytokine biosynthesis, which may contribute to the chronic low-grade inflammation observed with aging. We hypothesize that aging up-regulates the activation of p38 MAPK as well as the pro-inflammatory cytokines tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β) and interleukin-6 (IL-6) in mouse lung, and is accompanied by disturbances in oxidant-antioxidant status. In addition, the elevated protein levels of phosphorylated active form of p38 MAPK (phospho-p38 MAPK) with age are tissue-specific. To test this hypothesis, protein levels of phospho-p38 MAPK were determined using Western blot analysis in isolated lung, brain, heart, spleen, kidney and muscle of young (2-month-old) and aged (20-month-old) male C57BL/6J mice. Results show that phospho-p38 MAPK protein levels, not total-p38 MAPK, increased significantly (p<0.01, n=8) in lung and brain of 20-month-old mice. The activation of p38 MAPK in other tissues was not altered with age. Immunostaining showed that epithelial cells and alveolar macrophages in lung parenchyma were the major cellular sources of phospho-p38 MAPK immunity. As measured by enzyme-linked immunosorbent assay (ELISA), TNF-α, IL-1β and IL-6 in lung homogenates were elevated significantly with age, but there were no differences with age in serum levels except for IL-6. In addition, IL-1β and IL-6 were increased notably while TNF-α was not different with age in bronchoalveolar lavage fluid (BALF). Furthermore, the oxidant-antioxidant status was evaluated by measuring pro-oxidant malondialdehyde (MDA) levels and the activity of reactive oxygen species scavenging enzymes (i.e. superoxide dismutase (SOD) and glutathione (GSH)) in lung homogenates. The results showed that SOD and GSH decreased with age, while MDA did not change. In conclusion, our data demonstrate that p38 MAPK is activated during lung aging with a corresponding increase in pro-inflammatory cytokines and decrease in antioxidant capacity.

Unusual ciliary abnormalities in three 9/11 response workers

After the 9/11 terrorist attacks on the World Trade Center in New York in 2001, thousands of response workers were exposed to complex mixtures of toxins, pollutants, and carcinogens. Many developed illnesses involving the respiratory tract. We report unusual ultrastructural ciliary abnormalities in 3 response workers that corresponded to their respiratory and ciliary functional abnormalities. Each patient had respiratory cilia biopsies that were evaluated for motility and ultrastructural changes. Impaired ciliary motility was seen in 2 of the 3 patients. Each of the patients showed monomorphic ultrastructural abnormalities. Two of the patients showed identical triangular disarray of axonemal microtubules with peripheral doublets 1,4, and 7 forming the corners of the triangle and doublet 9 always more medially displaced than doublets 2, 3, 5, 6, and 8. Two workers had cilia in which axonemes were replaced by homogeneously dense cores. One of these also had cilia with triangular axonemes as previously described. The other had cilia with a geometric triangular to pentagonal shape. The ciliary abnormalities described here may represent a new class of primary ciliary dyskinesia in which abnormalities may have a genetic basis and a phenotypic expression that is prompted at the cellular level by local environmental conditions.

Asthma and chronic obstructive pulmonary disease: common genes, common environments?

Asthma and chronic obstructive pulmonary disease (COPD) show similarities and substantial differences. The Dutch hypothesis stipulated that asthma and COPD have common genetic and environmental risk factors (allergens, infections, smoking), which ultimately lead to clinical disease depending on the timing and type of environmental exposures (Postma and Boezen, Chest 2004;126:96S-104S). Thus, a particular group of shared genetic factors may lead to asthma when combined with specific environmental factors that are met at a certain stage in life, whereas combination with other environmental factors, or similar environmental factors at a different stage in life, will lead toward COPD. Multiple genes have been found for asthma and COPD. In addition to genes unique to these diseases, some shared genetic risk factors exist. Moreover, there are both common host risk factors and environmental risk factors for asthma and COPD. Here we put forward, based on the data available, that genes that affect lung development in utero and lung growth in early childhood in interaction with environmental detrimental stimuli, such as smoking and air pollution, are contributing to asthma in childhood and the ultimate development of COPD. Additional genes and environmental factors then drive specific immunological mechanisms underlying asthma, and others may contribute to the ultimate development of specific subtypes of COPD (i.e., airway disease with mucous hypersecretion, small airway disease, and emphysema). The genetic predisposition to the derailment of certain pathways may further help to define subgroups of asthma and COPD. In the end this may lead to stratification of patients by their genetic make-up and open new therapeutic prospects.

Interleukin-6 promotes pulmonary emphysema associated with apoptosis in mice

The IL-6 cytokine family, which signals via the shared gp130 coreceptor, is linked with the pathogenesis of emphysema. However, the definitive mechanisms by which these cytokines cause emphysema remain ill-defined. We took an in vivo genetic complementation approach to identify the specific IL-6 cytokine family members and gp130-regulated cellular processes that cause emphysema. We used gp130(F/F) mice homozygous for a subtle knock-in mutation in gp130 that deregulates intracellular signaling by the IL-6 cytokine family. The gp130(F/F) mice spontaneously develop emphysema by age 6 months. Within the IL-6 cytokine family, only IL-6 was significantly up-regulated in the lungs of gp130(F/F) mice, and the genetic targeting of IL-6 in gp130(F/F) mice (gp130(F/F):IL-6(-/-)) prevented emphysema. By contrast, the genetic ablation of receptor signaling via IL-11, which like IL-6 signals via a gp130 homodimer and uses the same signaling machinery, failed to ameliorate emphysema in gp130(F/F) mice. Among the disease-associated processes examined, emphysema strongly correlated with elevated alveolar cell apoptosis. Acute (4-day) exposure to cigarette smoke (CS) further augmented the expression of IL-6 in lungs of gp130(F/F) mice, and subchronic (6-week) exposure to CS exacerbated emphysematous and apoptotic changes in the lungs of gp130(F/F) but not gp130(F/F): IL-6(-/-) mice. IL-6 is the main causative agent of IL-6 cytokine family-induced emphysema, and operates to induce apoptosis in the lung. We propose that the discrete targeting of IL-6 signaling may provide an effective therapeutic strategy against human lung disease.

Interleukin-6 and airflow limitation in chemical warfare patients with chronic obstructive pulmonary disease

OBJECTIVES

Chronic obstructive pulmonary disease (COPD) is one of the main late complications of sulfur mustard poisoning. The aim of this study was to evaluate serum levels of interleukin (IL)-6 in war veterans with pulmonary complications of sulfur mustard poisoning and their correlation with severity of airways disease.

METHODS

Fifty consecutive patients with sulfur mustard poisoning and stable COPD, and of mean age 46.3 ± 9.18 years were enrolled in this study. Thirty healthy men were selected as controls and matched to cases by age and body mass index. Spirometry, arterial blood gas, six- minute walk test, BODE (body mass index, obstruction, dyspnea, and exercise capacity), and St George's Respiratory Questionnaire about quality of life were evaluated. Serum IL-6 was measured in both patient and control groups.

RESULTS

Fifty-four percent of patients had moderate COPD. Mean serum IL-6 levels were 15.01 ± standard deviation (SD) 0.61 pg/dL and 4.59 ± 3.40 pg/dL in the case and control groups, respectively (P = 0.03). There was a significant correlation between IL-6 levels and Global Initiative for Chronic Obstructive Lung Disease stage (r = 0.25, P = 0.04) and between IL-6 and BODE index (r = 0.38, P = 0.01). There was also a significant negative correlation between serum IL-6 and forced expiratory volume in one second (FEV(1), r = -0.36, P = 0.016).

CONCLUSION

Our findings suggest that serum IL-6 is increased in patients with sulfur mustard poisoning and COPD, and may have a direct association with airflow limitation.

Characterisation of COPD heterogeneity in the ECLIPSE cohort

Background

Chronic obstructive pulmonary disease (COPD) is a complex condition with pulmonary and extra-pulmonary manifestations. This study describes the heterogeneity of COPD in a large and well characterised and controlled COPD cohort (ECLIPSE).

Methods

We studied 2164 clinically stable COPD patients, 337 smokers with normal lung function and 245 never smokers. In these individuals, we measured clinical parameters, nutritional status, spirometry, exercise tolerance, and amount of emphysema by computed tomography.

Results

COPD patients were slightly older than controls and had more pack years of smoking than smokers with normal lung function. Co-morbidities were more prevalent in COPD patients than in controls, and occurred to the same extent irrespective of the GOLD stage. The severity of airflow limitation in COPD patients was poorly related to the degree of breathlessness, health status, presence of co-morbidity, exercise capacity and number of exacerbations reported in the year before the study. The distribution of these variables within each GOLD stage was wide. Even in subjects with severe airflow obstruction, a substantial proportion did not report symptoms, exacerbations or exercise limitation. The amount of emphysema increased with GOLD severity. The prevalence of bronchiectasis was low (4%) but also increased with GOLD stage. Some gender differences were also identified.

Conclusions

The clinical manifestations of COPD are highly variable and the degree of airflow limitation does not capture the heterogeneity of the disease.

Genetics of asthma and allergy: what have we learned?

The overall purpose of this review is to present an update on genetic approaches to understanding the susceptibility and expression (severity) of common diseases, such as asthma and allergy. Five key questions are addressed in this review: (1) What phenotypes are being studied? Multiple disease phenotypes in carefully characterized patients are required. (2) Are the same genes that are important in disease susceptibility important in disease severity? (3) Are there racial differences in disease expression and genetic susceptibility? (4) Are the genes important in normal variation in lung function important in asthma severity? (5) Are the genes important in other common diseases, such as chronic inflammatory diseases or chronic obstructive pulmonary disease, important in asthma or allergy? In addition, a discussion of some of current areas of research is presented, including the issue that current genome-wide association study results do not account for a significant portion of trait variability, the potential role of rare variants and large genome-sequencing studies, and pharmacogenetics: is there a role for basing treatment decisions on the results of genetic testing? Finally, the potential usefulness of DNA, personalized medicine, is discussed.

Pharmacogenetics of chronic obstructive pulmonary disease: challenges and opportunities

Similar to other common chronic diseases, chronic obstructive pulmonary disease (COPD) is a heterogeneous disorder with multiple disease subtypes. Candidate gene studies have found genetic associations for COPD-related phenotypes that may be relevant for pharmacogenetics studies, including lung function decline and COPD exacerbations. However, few COPD pharmacogenetics studies have been completed. Most studies have focused on the role of variants in the beta(2)-adrenergic receptor gene on bronchodilator response, but the findings have been inconclusive. Candidate gene studies highlight the concept that genes for COPD susceptibility may also be relevant in COPD pharmacogenetics. Currently, there are no clinical applications of pharmacogenetics to COPD therapy, but the use of pharmacogenetics to determine initial smoking cessation therapy may be closer to clinical application.

The aging immune system and its relationship to the development of chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is a chronic inflammatory disease of the lungs that usually manifests late in life. Physiologic and immunologic changes that occur in COPD often mimic changes seen in the aging lung. This has led some to characterize COPD as an "accelerated aging phenotype." At the molecular level, COPD and aging share common mechanisms and are associated with significant dysregulation of the immune systems. Aging and COPD are characterized by increases in proinflammatory cytokines such as interleukin (IL)-6 and tumor necrosis factor (TNF)-alpha, which are implicated in aging-related inflammatory diseases and correlate with degree of obstruction in COPD. There is an age-dependent decline in naïve T cells with oligoclonal expansion of CD8(+) CD28(null) T cells from chronic antigenic stimulation. The increase in CD8(+) CD28 (null) T regulatory cells inhibits antigen-specific CD4(+) T cell responses, leading to a decline in adaptive immune response. To compensate for the decline in the adaptive immune function there is a paradoxical up-regulation of innate immune system resulting in a proinflammatory state. The dysregulated adaptive immune system with activated innate immune responses seen with aging results in recruitment and retention of neutrophils, macrophages, and CD4(+) and CD8(+) T cells in the lungs of smokers with COPD. Once the inflammation is triggered, there is a self-perpetuating cascade of inflammation and lung parenchymal damage. This review will focus on how the aging immune system may contribute to COPD development later in life in susceptible individuals.

Optimized PCR with sequence specific primers (PCR-SSP) for fast and efficient determination of Interleukin-6 Promoter -597/-572/-174Haplotypes

Background

Interleukin-6 (IL-6) promoter polymorphisms at positions -597(G→A), -572(G→C) and -174(G→C) were shown to have a clinical impact on different major diseases. At present PCR-SSP protocols for IL-6 ^{-597/-572/-174}haplotyping are elaborate and require large amounts of genomic DNA.

Findings

We describe an improved typing technique requiring a decreased number of PCR-reactions and a reduced PCR-runtime due to optimized PCR-conditions.

Conclusion

This enables a fast and efficient determination of IL-6 ^{-597/-572/-174}haplotypes in clinical diagnosis and further evaluation of IL-6 promoter polymorphisms in larger patient cohorts.