Correlation between serum biomarkers and BODE index in patients with stable COPD

Novel Applications of Biomarkers in Chronic Obstructive Pulmonary Disease

Chronic obstructive pulmonary disease (COPD) is an important health problem and an increasing cause of morbidity and mortality worldwide. Currently, COPD is considered a multisystem disease. Although it primarily affects the lungs, structural and functional changes occur in other organs due to systemic inflammation. It is stated that in patients with COPD, airway and systemic inflammatory markers are increased and that these markers are high are associated with a faster decline in lung functions. In recent years, numerous articles have been published on the discovery and evaluation of biomarkers in COPD. Many markers have also been studied to accurately assess COPD exacerbations and provide effective treatment. However, based on the evidence from published studies, a single molecule has not been adequately validated for broad clinical use.

Are Systemic Manifestations Ascribable to COPD in Smokers? A Structural Equation Modeling Approach

Whether the systemic manifestations observed in Chronic Obstructive Pulmonary Disease (COPD) are ascribable to lung dysfunction or direct effects of smoking is in debate. Structural Equations Modeling (SEM), a causal-oriented statistical approach, could help unraveling the pathways involved, by enabling estimation of direct and indirect associations between variables. The objectives of the study was to investigate the relative impact of smoking and COPD on systemic manifestations, inflammation and telomere length. In 292 individuals (103 women; 97 smokers with COPD, 96 smokers without COPD, 99 non-smokers), we used SEM to explore the pathways between smoking (pack-years), lung disease (FEV₁, K_CO), and the following parameters: arterial stiffness (aortic pulse wave velocity, PWV), bone mineral density (BMD), appendicular skeletal muscle mass (ASMM), grip strength, insulin resistance (HOMA-IR), creatinine clearance (eGFR), blood leukocyte telomere length and inflammatory markers (Luminex assay). All models were adjusted on age and gender. Latent variables were created for systemic inflammation (inflammatory markers) and musculoskeletal parameters (ASMM, grip strength, BMD). SEM showed that most effects of smoking were indirectly mediated by lung dysfunction: e.g. via FEV₁ on musculoskeletal factor, eGFR, HOMA-IR, PWV, telomere length, CRP, white blood cells count (WBC) and inflammation factor, and via K_CO on musculoskeletal factor, eGFR and PWV. Direct effects of smoking were limited to CRP and WBC. Models had excellent fit. In conclusion, SEM highlighted the major role of COPD in the occurrence of systemic manifestations while smoking effects were mostly mediated by lung function.

Impact of Cigarette Smoking on Serum Pro- and Anti-Inflammatory Cytokines and Growth Factors

Inflammation plays a key role in the initiation, progression, and clinical manifestation of atherosclerosis. Cigarette smoking is a risk factor for atherosclerosis and cardiovascular disease. The aim of the current study was to investigate the serum concentrations of 12 cytokines and growth factors (EGF, INF-γ, IL-1α/-1β/-2/-4/-6/-8/-10, MCP-1, TNF-α, and VEGF) in an Iranian population, including 192 smokers, comparing these values with concentrations in nonsmokers. One hundred and ninety-two cases were enrolled from the Mashhad University of Medical Sciences. Of these cases, 82 were cigarette smokers and 110 were nonsmokers. Sex and age were matched for the two groups. The serum concentration of 12 cytokines and growth factors were determined using EV-3513-cytokine-biochip arrays, by competitive chemiluminescence immunoassays. The level of serum MCP-1 was significantly ( p < .001) lower in the female group of cigarette smokers (mean = 88.1 dL/ng), compared with nonsmokers (mean = 155.6 dL/ng). There were no significant differences for the other cytokines and growth factors between the groups. Our finding demonstrate the association of MCP-1 with cigarette smoking, supporting further studies in larger population on evaluating the role of cigarette smoking on pro-/anti-inflammatory cytokines.

Usefulness of neutrophil to lymphocyte ratio in patients with chronic obstructive pulmonary disease: a prospective observational study

BACKGROUND/AIMS

Neutrophil to lymphocyte ratio (NLR) in peripheral blood is a useful systemic inflammatory response biomarker. However, NLR has not been studied in patients with chronic obstructive pulmonary disease (COPD). This study was aimed to evaluate the usefulness of NLR in patients with COPD.

METHODS

NLR was prospectively measured and compared in patients with COPD exacerbation (n = 59), patients with stable COPD (n = 61), and healthy controls (n = 28). NLR in patients with COPD exacerbation was repeatedly measured in the convalescent period. The correlation between NLR and clinical parameters was evaluated, and the predictors for respiratory hospitalization were analyzed by multivariate logistic regression.

RESULTS

NLR values were significantly higher in patients with COPD exacerbation compared with stable COPD patients and controls (12.4 ± 10.6, 2.4 ± 0.7, 1.4 ± 0.5, respectively; p < 0.001). NLR was significantly decreased during the convalescent period in patients with COPD exacerbation (4.5 ± 4.6 vs. 11.5 ± 8.8, p < 0.001). NLR exhibited a significant correlation with the body mass index, degree of airway obstruction, dyspnea, and exercise capacity (BODE) index, the 6-minute walk test, and the modified Medical Research Council scale. NLR ≥ 2.8 was an independent predictor with a borderline significance for respiratory hospitalization (odds ratio, 2.083; p = 0.079). Body mass index and forced expiratory volume in 1 second were independent predictors for respiratory hospitalization.

CONCLUSIONS

NLR is a straightforward and effective biomarker of COPD exacerbation that may serve as a predictor for respiratory hospitalization in patients with COPD.

Could "red cell distribution width" predict COPD severity?

BACKGROUND AND OBJECTIVES

Erythrocyte morphology changes not only by primary hematological diseases but also by systemic inflammation, ineffective erythropoiesis and nutritional deficiencies. Red blood cell distribution width (RDW) is a parameter reflecting erythrocyte morphology. We aimed to investigate the relationship of RDW with chronic obstructive pulmonary disease (COPD) stages, BODE index and survival in COPD patients.

METHODS

Medical records of 385 COPD patients between July 2004 and November 2005 were studied retrospectively. Demographic features, BODE index factors and oxygen saturation were recorded. Survival analysis of all patients by 2014 was performed. Measured RDW values at the time of the inclusion were evaluated.

RESULTS

Mean age of the patients was 65.6±9.6 years. Distribution of the COPD stages of the patients were stage 1: 16%, stage 2: 52%, stage 3: 26%, stage 4: 6%. RDW was found significantly different between stages. The highest RDW was observed in the very severe stage (p<0.001). Median of BODE index was 1 (0-3). As the BODE index increased RDW also increased (p<0.001). When the patients were grouped according to the laboratory upper limit of RDW, survival rate was 31% in the RDW >14.3% group and 75% in the RDW <14.3% group.

CONCLUSION

The variability in the size of circulating erythrocytes increases as the COPD severity progresses. Therefore, a simple and noninvasive test, such as RDW, might be used as a biomarker in the evaluation of the severity of COPD. At the same time, there seems to be a correlation between the survival of COPD patients and RDW.

The Impact of Obstructive Sleep Apnea and Tobacco Smoking on Endothelial Function

BACKGROUND

Endothelial dysfunction has been recognized to occur in the context of obstructive sleep apnea (OSA) or tobacco smoking. However, the deleterious effect on vascular function with concurrence of both conditions is largely unknown.

OBJECTIVE

To investigate whether the concurrence of OSA and smoking poses an additive detriment to endothelial dysfunction.

METHODS

Chinese men without a history of chronic medical illness were invited to complete a questionnaire including smoking pack-year exposure, polysomnography and peripheral arterial tonometry (PAT) for endothelial function. Serum 8-isoprostane, advanced oxidation protein products (AOPP) and monocyte chemo-attractant protein-1 (MCP-1) were measured.

RESULTS

114 men were successfully enrolled. PAT ratio, adjusted for age and body mass index, correlated inversely with overall severity of OSA: apnea-hypopnea index (AHI), r = -0.160 (p = 0.092); oxygen desaturation index, r = -0.214 (p = 0.024); duration of oxygen saturation <90%, r = -0.219 (p = 0.020); and minimum oxygen saturation, r = 0.250 (p = 0.008). The PAT ratio decreased with increasing pack-year group (p = 0.018). It was lower with concurrent smoking history and moderate-severe OSA (AHI ≥15/h) compared to having one or neither factor (p = 0.011). Serum levels of 8-isoprostane and AOPP were positively related to severity of OSA, while MCP-1 correlated with smoking quantity. Multiple linear regression analyses showed that severity of intermittent hypoxia, MCP-1 and pack-year exposure were independent predictors of PAT ratio.

CONCLUSION

While OSA, in particular intermittent hypoxemia, and tobacco smoking were independent risk factors, the concurrence of moderate-severe OSA and smoking was associated with the most severe impairment in endothelial function.

Systemic cytokine signaling via IL-17 in smokers with obstructive pulmonary disease: a link to bacterial colonization?

We examined whether systemic cytokine signaling via interleukin (IL)-17 and growth-related oncogene-α (GRO-α) is impaired in smokers with obstructive pulmonary disease including chronic bronchitis (OPD-CB). We also examined how this systemic cytokine signaling relates to bacterial colonization in the airways of the smokers with OPD-CB. Currently smoking OPD-CB patients (n=60, corresponding to Global initiative for chronic Obstructive Lung Disease [GOLD] stage I–IV) underwent recurrent blood and sputum sampling over 60 weeks, during stable conditions and at exacerbations. We characterized cytokine protein concentrations in blood and bacterial growth in sputum. Asymptomatic smokers (n=10) and never-smokers (n=10) were included as control groups. During stable clinical conditions, the protein concentrations of IL-17 and GRO-α were markedly lower among OPD-CB patients compared with never-smoker controls, whereas the asymptomatic smoker controls displayed intermediate concentrations. Notably, among OPD-CB patients, colonization by opportunistic pathogens was associated with markedly lower IL-17 and GRO-α, compared with colonization by common respiratory pathogens or oropharyngeal flora. During exacerbations in the OPD-CB patients, GRO-α and neutrophil concentrations were increased, whereas protein concentrations and messenger RNA for IL-17 were not detectable in a reproducible manner. In smokers with OPD-CB, systemic cytokine signaling via IL-17 and GRO-α is impaired and this alteration may be linked to colonization by opportunistic pathogens in the airways. Given the potential pathogenic and therapeutic implications, these findings deserve to be validated in new and larger patient cohorts.

Selective targeting of TGF-β activation to treat fibroinflammatory airway disease

Airway remodeling, caused by inflammation and fibrosis, is a major component of chronic obstructive pulmonary disease (COPD) and currently has no effective treatment. Transforming growth factor-β (TGF-β) has been widely implicated in the pathogenesis of airway remodeling in COPD. TGF-β is expressed in a latent form that requires activation. The integrin αvβ8 (encoded by the itgb8 gene) is a receptor for latent TGF-β and is essential for its activation. Expression of integrin αvβ8 is increased in airway fibroblasts in COPD and thus is an attractive therapeutic target for the treatment of airway remodeling in COPD. We demonstrate that an engineered optimized antibody to human αvβ8 (B5) inhibited TGF-β activation in transgenic mice expressing only human and not mouse ITGB8. The B5 engineered antibody blocked fibroinflammatory responses induced by tobacco smoke, cytokines, and allergens by inhibiting TGF-β activation. To clarify the mechanism of action of B5, we used hydrodynamic, mutational, and electron microscopic methods to demonstrate that αvβ8 predominantly adopts a constitutively active, extended-closed headpiece conformation. Epitope mapping and functional characterization of B5 revealed an allosteric mechanism of action due to locking-in of a low-affinity αvβ8 conformation. Collectively, these data demonstrate a new model for integrin function and present a strategy to selectively target the TGF-β pathway to treat fibroinflammatory airway diseases.

Circulating hematopoietic progenitor cells are decreased in COPD

RATIONALE

Bone marrow derived progenitor cells participate in the repair of injured vessels. The lungs of individuals with emphysema have reduced alveolar capillary density and increased endothelial apoptosis. We hypothesized that circulating levels of endothelial and hematopoietic progenitor cells would be reduced in this group of patients.

OBJECTIVES

The goal of this study was to measure circulating levels of endothelial progenitor cells (EPCs) and hematopoietic progenitor cells (HPCs) in subjects with COPD and to determine if progenitor levels correlated with disease severity and the presence of emphysema.

METHODS

Peripheral blood mononuclear cells were isolated from 61 patients with COPD and 32 control subjects. Levels of EPCs (CD45(dim) CD34+) and HPCs (CD45(+) CD34(+) VEGF-R2(+)) were quantified using multi-parameter flow cytometry. Progenitor cell function was assessed using cell culture assays. All subjects were evaluated with spirometry and CT scanning.

MEASUREMENTS AND MAIN RESULTS

HPC levels were reduced in subjects with COPD compared to controls, whereas circulating EPC levels were similar between the two groups. HPC levels correlated with severity of obstruction and were lowest in subjects with severe emphysema. These associations remained after correction for factors known to affect progenitor cell levels including age, smoking status, the use of statin medications and the presence of coronary artery disease. The ability of mononuclear cells to form endothelial cell colony forming units (EC-CFU) was also reduced in subjects with COPD.

CONCLUSIONS

HPC levels are reduced in subjects with COPD and correlate with emphysema phenotype and severity of obstruction. Reduction of HPCs may disrupt maintenance of the capillary endothelium, thereby contributing to the pathogenesis of COPD.

Comparison of arterial and venous blood biomarker levels in chronic obstructive pulmonary disease

PURPOSE

The development of novel biomarkers is an unmet need in chronic obstructive pulmonary disease (COPD). Arterial blood comes directly from the lung and venous blood drains capillary beds of the organ or tissue supplied. We hypothesized that there would be a difference in levels of the biomarkers metalloproteinase 9 (MMP-9), vascular endothelial growth factor A (VEGF-A) and interleukin 6 (IL-6) in arterial compared with venous blood. 

METHODS

Radial artery and brachial vein blood samples were taken simultaneously in each of 12 patients with COPD and seven controls with normal lung function. Circulating immunoreactive MMP-9, VEGF-A and IL-6 levels in serum were measured using quantitative enzyme-linked immunosorbent assays. RESULTS were compared using a Student's paired t test. The study was powered to determine whether significant differences in cytokine levels were present between paired arterial and venous blood samples.  

RESULTS

In the 12 patients with COPD, four were female, and age ranged 53-85 years, mean age 69 years. Three patients in the control group were female, with age range 46-84 years, mean age 64.7 years. In the COPD group, three patients had mild, five moderate and four severe COPD. No significant difference was found between arterial and venous levels of MMP-9, VEGF-A or IL-6. 

CONCLUSIONS

In this pilot study, levels of the measured biomarkers in arterial compared with venous blood in both COPD patients and healthy controls did not differ. This suggests that as we continue to chase the elusive biomarker in COPD as a potential tool to measure disease activity, we should focus on venous blood for this purpose.

Selection of disease-specific biomarkers by integrating inflammatory mediators with clinical informatics in AECOPD patients: a preliminary study

Systemic inflammation is a major factor influencing the outcome and quality of patient with chronic obstructive pulmonary disease (COPD) and acute exacerbations (AECOPD). Because of the inflammatory complexity, a great challenge is still confronted to optimize the identification and validation of disease-specific biomarkers. This study aimed at developing a new protocol of specific biomarker evaluation by integrating proteomic profiles of inflammatory mediators with clinical informatics in AECOPD patients, understand better their function and signal networks. Plasma samples were collected from healthy non-smokers or patients with stable COPD (sCOPD) or AECOPD on days 1 and 3 of the admission and discharging day (day 7–10). Forty chemokines were measured using a chemokine multiplex antibody array. Clinical informatics was achieved by a Digital Evaluation Score System (DESS) for assessing severity of patients. Chemokine data was compared among different groups and its correlation with DESS scores was performed by SPSS software. Of 40 chemokines, 30 showed significant difference between sCOPD patients and healthy controls, 16 between AECOPD patients and controls and 13 between AECOPD patients and both sCOPD and controls, including BTC, IL-9, IL-18Bpa, CCL22,CCL23, CCL25, CCL28, CTACK, LIGHT, MSPa, MCP-3, MCP-4 and OPN. Of them, some had significant correlation with DESS scores. There is a disease-specific profile of inflammatory mediators in COPD and AECOPD patients which may have a potential diagnostics together with clinical informatics of patients. Our preliminary study suggested that integration of proteomics with clinical informatics can be a new way to validate and optimize disease-special biomarkers.

Biomarkers in chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is a complex disease with multiple phenotypes that cannot be identified through measurement of lung function alone. The importance of COPD risk assessment, phenotype identification, and diagnosis of exacerbation magnify the need for validated biomarkers in COPD. A large number of potential biomarkers have already been assessed and some appear promising, in particular fibrinogen, which is likely to be the first COPD biomarker presented to the Food and Drug Administration for qualification in the drug approval process. Blood fibrinogen and c-reactive protein (CRP) have been associated with the presence of COPD and, in some instances, future risk of developing COPD in targeted populations. Sputum neutrophil counts have been used preliminarily as biomarkers of favorable response to therapy in COPD, but use in clinical settings may be limited. Other potential blood biomarkers include pulmonary and activation-regulated chemokine (PARC/CCL-18) and the clara cell secretory protein 16 (CC-16). Integrative indices, such as the BODE index, provide a framework to determine prognosis, predict outcome, and may be responsive to therapeutic interventions. Computed tomography provides a means to assess phenotypes and identify the relative extents of small airways disease and emphysema, which themselves may inform prognosis and therapeutic decision making. Fibrinogen and other markers of systemic inflammation are elevated in the context of acute COPD exacerbations and may also identify those at risk of accelerated lung function decline and hospitalization. So far, no single biomarker in COPD warrants wide acceptance emphasizing the need for future investigation of biomarkers in large-scale longitudinal studies.

Association between periodontitis and chronic obstructive pulmonary disease in a Chinese population

BACKGROUND

A relationship between periodontitis and chronic respiratory disease has been suggested by recent studies. The aim of this study is to explore the association between periodontitis and chronic obstructive pulmonary disease (COPD) in a Chinese population.

METHODS

We conducted a case-control study of 581 COPD cases and 438 non-COPD controls. Lung function examination, a 6-minute walk test, and the British Medical Research Council questionnaire were performed. Periodontal clinical examination index included probing depth (PD), attachment loss (AL), bleeding index (BI), plaque index (PI), and alveolar bone loss. A validated index for predicting COPD prognosis, the body mass index, airflow obstruction, dyspnea, and exercise capacity (BODE) index, was also calculated.

RESULTS

Participants with more severe COPD were more likely to have severe periodontal disease. PD, AL, PI, alveolar bone loss, and the number of teeth were significantly associated with all stages of COPD (all P <0.001). When compared to controls (BODE = 0), participants with higher BODE scores had significantly higher AL (P <0.001), BI (P = 0.027), PI (P <0.001), alveolar bone loss (P <0.001), and the number of teeth (P <0.001). PI appeared to be the main periodontal health-related factor for COPD, with an odds ratio (OR) = 9.01 (95% CI = 3.98 to 20.4) in the entire study population OR = 8.28 (95% CI = 2.36 to 29.0), OR = 5.89 (95% CI = 2.64 to 13.1), and OR = 2.46 (95% CI = 1.47 to 4.10) for current, smokers, and non-smokers, respectively.

CONCLUSION

Our study found a strong association between periodontitis and COPD, and PI seemed to be a major periodontal factor for predicting COPD among Chinese adults.

Relationship between the anti-inflammatory properties of salmeterol/fluticasone and the expression of CD4⁺CD25⁺Foxp3⁺ regulatory T cells in COPD

BACKGROUND

Salmeterol and fluticasone combination (SFC) has anti-inflammatory effects and improves clinical symptoms in patients with chronic obstructive pulmonary disease (COPD). However, the anti-inflammatory mechanism of SFC remains unclear. In this study, we investigated the inflammatory responses of COPD, as well as the relationship of the inflammatory factors with the levels of CD4+CD25+Foxp3+ regulatory T cells (Foxp3+Tregs) after SFC therapy.

METHODS

Twenty-one patients with moderate or severe COPD received treatment with 50/500 μg of SFC twice a day for 12 weeks. Before and after treatment, the patients were evaluated using the Modified Medical Research Council (MMRC) dyspnea scale and by conducting a 6-min walk test. The number of neutrophils, monocytes and lymphocytes in induced sputum were counted. Levels of cytokines, including pre-inflammatory IL-8, TNF-α, IL-17A and cytokine IL-10, in the sputum supernatant and peripheral blood were measured by ELISA. The proportion of Foxp3+Tregs in the total CD4+ T cell of the peripheral blood was determined by flow cytometry. The relationship between IL-17A levels and the percentage of Foxp3+Tregs was analyzed by statistical analysis.

RESULTS

After treatment with SFC, the forced expiratory volume in 1 s as a percentage of predicted values (FEV1%) and the 6-min walk distance in the COPD patients significantly increased, while dyspnea scores decreased. The total number of cells, neutrophils, and the percentage of neutrophils in induced sputum reduced notably, while the proportion of monocytes was significantly increased. Levels of the inflammatory cytokines IL-8, TNF-α, and IL-17A in the sputum supernatant and in the blood were markedly lowered, while IL-10 levels were unchanged. The proportion of Foxp3+Tregs in the total CD4+T cell population in the peripheral blood was drastically higher than that before treatment. The level of IL-17A was negatively correlated with the proportion of Foxp3+Tregs in CD4+T cells.

CONCLUSION

SFC can reduce the levels of inflammatory factors and improve symptoms of COPD. The levels of inflammatory factors are associated with the variation of Foxp3+Tregs in COPD.

TRIAL REGISTRATION

This study was registered with http://www.chictr.org (Chinese Clinical Trial Register) as follows: ChiCTR-TNC-10001270.

Mouse and human lung fibroblasts regulate dendritic cell trafficking, airway inflammation, and fibrosis through integrin αvβ8-mediated activation of TGF-β

The airway is a primary portal of entry for noxious environmental stimuli that can trigger airway remodeling, which contributes significantly to airway obstruction in chronic obstructive pulmonary disease (COPD) and chronic asthma. Important pathologic components of airway remodeling include fibrosis and abnormal innate and adaptive immune responses. The positioning of fibroblasts in interstitial spaces suggests that they could participate in both fibrosis and chemokine regulation of the trafficking of immune cells such as dendritic cells, which are crucial antigen-presenting cells. However, physiological evidence for this dual role for fibroblasts is lacking. Here, in two physiologically relevant models - conditional deletion in mouse fibroblasts of the TGF-β-activating integrin αvβ8 and neutralization of αvβ8 in human COPD fibroblasts - we have elucidated a mechanism whereby lung fibroblast chemokine secretion directs dendritic cell trafficking, in a manner that is critically dependent on αvβ8-mediated activation of TGF-β by fibroblasts. Our data therefore indicate that fibroblasts have a crucial role in regulating both fibrotic and immune responses in the lung.

MCP1 -2518 polymorphism and chronic obstructive pulmonary disease in Taiwanese men

Monocyte chemoattractant protein-1 (MCP-1) plays a major role in the recruitment of inflammatory cells to the lungs of patients with chronic obstructive pulmonary disease (COPD). However, the influence of MCP1 gene polymorphism on COPD development has not been studied. This study aimed to investigate the association between MCP1 -2518 polymorphisms and COPD and between this polymorphism and plasma MCP-1 levels. The plasma MCP-1 was measured by using an enzyme-linked immunosorbent assay and polymorphisms detection was performed by denaturing high-performance liquid chromatography. COPD group had higher plasma MCP1 levels than healthy participants (257.0 versus 194.4 pg/mL) in the univariate analysis (P = .005); and in stepwise liner regression analysis after adjustment for age, alcohol, body mass index, cancer history, and steroid use (P = .002; 95% confidence interval [CI]: 30.72-128.02). Plasma MCP-1 was negatively correlated with forced expiratory volume in one second (FEV(1)%) (P = .003; r = -.274). SNPStats including codominant, dominant, recessive, overdominant, and log-additive model analysis showed MCP1 -2518 polymorphisms had no association with the risk of COPD. Generalized linear model showed no association between plasma MCP-1 levels and MCP1 -2518 genotypes. In conclusion, there is no association between MCP1 -2518 gene polymorphisms and COPD or between this gene polymorphisms and plasma MCP-1 levels in the Taiwanese men.

Biomarkers in COPD

Although there is increasing interest in using pulmonary biomarkers for a more complete and clinically relevant assessment of COPD and a plethora of biomarkers are becoming available, there is little information regarding their reproducibility and correlation with other outcome measurements in COPD. The lack of well-validated biomarkers that can be used for monitoring disease activity, predicting future clinical outcomes and the effect of therapeutic interventions highlights the factual need to identify new biomarkers in COPD. It is likely that, using what is called 'integrative functional informatics', which is a novel direction in the interfacing and integration of different technologies (genomics, proteomics, metabolomics and metabonomics, pharmacogenetics, and integrative approaches) for collection and analysis of data on biomarkers, we will be able to identify robust, reliable, and reproducible biomarkers in COPD.