The repeatability of interleukin-6, tumor necrosis factor-alpha, and C-reactive protein in COPD patients over one year

Correlation between serum bilirubin, blood uric acid, and C-reactive protein and the severity of chronic obstructive pulmonary disease

OBJECTIVE

To explore the correlation between serum bilirubin, blood uric acid, and C-reactive protein (CRP) and the severity of chronic obstructive pulmonary disease (COPD).

METHODS

Patients with COPD who were admitted to our hospital between March 2020 and March 2023 were retrospectively studied. Based on whether their condition progressed to the acute exacerbation stage, they were divided into an exacerbation group (100 cases) and a stability group (100 cases). The clinical data from both groups were analysed to assess the correlations between serum bilirubin, blood uric acid, CRP, and the severity of COPD.

RESULTS

Univariate analysis indicated significant differences in the neutrophil-to-lymphocyte ratio (t = 5.678, P < 0.05), α-hydroxybutyrate dehydrogenase (t = 5.862, P < 0.05), total bilirubin (t = 4.341, P < 0.05), direct bilirubin (t = 5.342, P < 0.05), indirect bilirubin (t = 5.452, P < 0.05), blood uric acid (t = 4.698, P < 0.05), and CRP (t = 4.892, P < 0.05) between the two groups. Multivariate analysis revealed that total bilirubin, blood uric acid, and CRP were positively correlated with exacerbations of COPD (regression coefficients were 0.413, 0.354, and 0.356, respectively; P < 0.05). The evaluation of predictive value showed that the combined predictive value of these three indicators was the highest, with an AUC of 0.823 (95% CI: 0.754-0.911).

CONCLUSION

Serum bilirubin, blood uric acid, and CRP levels are elevated in patients with acute exacerbations of COPD (AECOPD), showing good consistency in predicting the occurrence of AECOPD. The combined diagnostic value of these three indicators is greater than that of any single indicator, providing a reference for the early clinical prediction of AECOPD.

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

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

Effects of mixed heavy metals on obstructive lung function: findings from epidemiological and toxicogenomic data

The molecular mechanisms and associations of mixed heavy metals (lead, mercury, and cadmium) on obstructive lung function (OLF) in males and females remain unknown. Here, we evaluated the interaction between the forced expiratory volume in one second (FEV1)/forced vital capacity (FVC) ratio and three common heavy metals in males and females (n = 6221). Molecular processes involved in OLF development caused by mixed heavy metals were also identified to corroborate the earlier findings. In both males and females, as well as across the entire population, we found that serum cadmium levels were inversely related to the FEV1/FVC ratio. Interactions between serum cadmium and lead, as well as cadmium and mercury, were observed in relation to the FEV1/FVC ratio. Additionally, we observed negative correlations between the FEV1/FVC ratio and mixed serum cadmium, lead, and mercury in both men and women as well as in the overall population. Seven genes were identified as contributing to the etiology of OLF and targeted by combined heavy metals in silico analysis (CYP1A1, CRP, CXCL8, HMOX1, IL6, NOS2, and TNF). The primary relationships between these genes were co-expression interactions. The significant transcription factors and miRNAs associated with OLF and a combination of the examined heavy metals were identified as NFKB2, hsa-miR-155-5p, and hsa-miR-203a-3p. The main biological processes involved in the emergence of OLF induced by mixed heavy metals were listed as inflammatory and oxidative stress pathways, lung fibrosis, chronic obstructive pulmonary disease, as well as cytokine activity, monooxygenase activity, oxidoreductase activity, and interleukin-8 production. Threshold estimations and miRNA sponge patterns for heavy metal exposure levels associated with OLF were evaluated for both males and females. This study found that cadmium plays the most important role in the mixture of cadmium, lead, and mercury in the pathogenesis of OLF. Future studies are required to verify our findings and uncover the molecular mechanisms of long-term exposure to a variety of heavy metals, especially cadmium, in other populations, including children, adolescents, and the elderly.

Chronic Exposure to Secondary Organic Aerosols Causes Lung Tissue Damage

Recently, secondary organic aerosols (SOAs) emerged as a predominant component of fine particulate matter. However, the pathogenic mechanism(s) of SOAs are still poorly understood. Herein, we show that chronic exposure of mice to SOAs resulted in lung inflammation and tissue destruction. Histological analyses found lung airspace enlargement associated with massive inflammatory cell recruitment predominated by macrophages. Concomitant with such cell influx, our results found changes in the levels of a series of inflammatory mediators in response to SOA. Interestingly, we observed that the expression of the genes encoding for TNF-α and IL-6 increased significantly after one month of exposure to SOAs; mediators that have been largely documented to play a role in chronic pulmonary inflammatory pathologies. Cell culture studies confirmed these in vivo findings. Of importance as well, our study indicates increased matrix metalloproteinase proteolytic activity suggesting its contribution to lung tissue inflammation and degradation. Our work represents the first in vivo study, which reports that chronic exposure to SOAs leads to lung inflammation and tissue injury. Thus, we hope that these data will foster new studies to enhance our understanding of the underlying pathogenic mechanisms of SOAs and perhaps help in the design of therapeutic strategies against SOA-mediated lung injury.

Effect of crocin of Crocus sativus L. on serum inflammatory markers (IL-6 and TNF-α) in chronic obstructive pulmonary disease patients: a randomised, double-blind, placebo-controlled trial

Different factors, such as inflammation, oxidative stress, extracellular matrix degradation and apoptosis, affect the pathophysiology of chronic obstructive pulmonary disease (COPD), as a progressive disease characterised by permanent airflow limitation. Herbal supplements with anti-inflammatory and antioxidant properties can help treat certain chronic diseases. The current study aimed at investigating the preventive effects of crocin supplementation on the serum concentrations of IL-6, TNF-α, exercise capacity and pulmonary function tests (PFT) in patients with COPD. The present prospective randomised clinical trial equally divided fifty-seven patients with COPD into a placebo and an intervention group, who respectively received a placebo and crocin (15 mg twice day for 12 weeks) as a supplement. ELISA was used to measure serum levels of IL-6 and TNF-α, also PFT and exercise capacity based on 6-min walking distance test (6MWD), which was performed at the beginning and end of the study. Crocin improved the results of PFT (P < 0·05) and 6-MWD (P < 0·001) and exerted preventive effects by increasing the serum levels of IL-6 in patients with COPD compared with those in the placebo group (P < 0·05). Intervention with crocin significantly lowered serum levels of TNF-α at the end of the study (P < 0·01). The present findings suggest crocin supplementation improves exercise capacity and PFT in patients with COPD by reducing serum levels of inflammatory factors.

Changes in systemic inflammation after pulmonary rehabilitation in patients with COPD and severe physical inactivity - an exploratory study

Background: Severe physical inactivity (SPI) in patients with COPD is associated with a poor prognosis. It is unknown whether there is a link between SPI and systemic inflammation, and if systemic inflammation in SPI changes following pulmonary rehabilitation (PR).

Methods: A prospective, observational study of patients referred for at least 7 weeks of PR comprising 2 h of exercise therapy and education twice weekly. At baseline and after PR, daily physical activity level (PAL) was measured with a validated activity monitor, SenseWear^® as well as systemic inflammation: b-eosinophils, p-fibrinogen, p-CRP, s-IL-6 and s-CD 163. SPI was defined as PAL <1.4.

Results: At baseline, SPI was present in 31 of the 57 patients included, and 23% (7/31) improved to non-SPI after PR. We observed no differences between patients with SPI and non-SPI, except baseline plasma fibrinogen level was slightly yet significantly higher in patients with SPI (median 13.3 [6.2–23.6] vs 11.2 [6.5–16.7] µmol/l) but change in fibrinogen levels differed insignificantly between patients who improved to non-SPI at follow-up compared to patients with persistent SPI (−0.6 [−16.9–9.9] vs −0.4 [−11.2–1.2] µmol/l).

Conclusion: SPI in COPD appears not to be associated with a distinct inflammatory profile compared to less sedentary COPD patients attending pulmonary rehabilitation. Currently biomarkers have no role in the detection of SPI in COPD.

Tocotrienols: Dietary Supplements for Chronic Obstructive Pulmonary Disease

Chronic obstructive pulmonary disease (COPD) is one of the leading causes of death worldwide. Emphysema and chronic bronchitis are the two major phenotypes of COPD, which have many symptoms, such as dyspnea, chronic cough, and mucus overproduction. Emphysema is characterized by the destruction of the alveolar wall, while chronic bronchitis is characterized by limitations in expiratory airflow. Cigarette smoking is the most significant risk factor for the pathogenesis of COPD in the developed world. Chronic inflammation contributes to the onset and progression of the disease and furthers the risk of comorbidities. Current treatment options and prevention strategies for COPD are very limited. Tocotrienols are a group of vitamin E molecules with antioxidant and anti-inflammatory properties. Individual tocotrienols (α, γ, and δ) have shown their ability to attenuate inflammation specifically via suppressing nuclear factor-κB-mediated cytokine production. The δ- and γ-forms of tocotrienols have been indicated as the most effective in the prevention of macrophage infiltration, production of reactive oxygen species, and cytokine secretion. This review briefly discusses the pathogenesis of COPD and the role of inflammation therein. Furthermore, we summarize the in vitro and in vivo evidence for the anti-inflammatory activity of tocotrienols and their potential application to COPD management. Coupled with the bioavailability and safety profile of tocotrienols, the ability of these compounds to modulate COPD progression by targeting the inflammation pathways renders them potential candidates for novel therapeutic approaches in the treatment of COPD patients.

GTS-21, an α7nAChR agonist, suppressed the production of key inflammatory mediators by PBMCs that are elevated in COPD patients and associated with impaired lung function

Chronic obstructive pulmonary disease (COPD) is a lung inflammatory disease characterized by progressive airflow limitation, chronic respiratory symptoms and frequent exacerbations. There is an unmet need to identify novel therapeutic alternatives beside bronchodilators that prevent disease progression. Levels of both Nitric Oxide (NO) and IL-6 were significantly increased in the plasma of patients in the exacerbation phase (ECOPD, n = 13) when compared to patients in the stable phase (SCOPD, n = 38). Levels of both NO and IL-6 were also found to inversely correlate with impaired lung function (%FEV1 predicted). In addition, there was a strong positive correlation between levels of IL-6 and NO found in the plasma of patients and those spontaneously produced by their peripheral blood mononuclear cells (PBMCs), identifying these cells as a major source of these key inflammatory mediators in COPD. GTS-21, an agonist for the alpha 7 nicotinic receptors (α7nAChR), was found to exert immune-modulatory actions in PBMCs of COPD patients by suppressing the production of IL-6 and NO. This study provides the first evidence supporting the therapeutic potential of α7nAChR agonists in COPD due to their ability to suppress the production of key inflammatory markers associated with disease severity.

Predictive Value of Combining Inflammatory Biomarkers and Rapid Decline of FEV1 for COPD in Chinese Population: A Prospective Cohort Study

Background

In China, the high prevalence and mortality rate of Chronic Obstructive Pulmonary Disease (COPD) and the poor intervention effect makes it into a heavy social burden. The main reason is that the current diagnosis of COPD mainly based on the static lung function, which is difficult for early intervention. Through matching a predictive model for high-risk groups of COPD that rewards FEV₁ rapid decline as the core, we will establish the early warning model and prove its validity and socio-economic value.

Methods

This is a multi-center, prospective, cohort study. A total of 10,000 people aged 40∼75 without lung disease will be recruited and followed for 3 years. Some questionnaires such as St George’s Respiratory Questionnaire (SGRQ), income class, educational level, comorbidity, smoking habit, and biomass smoke exposure history will be collected. The baseline level of Interleukin 6 (IL-6), high-sensitivity C-reactive Protein (hs-CRP), microRNAs-23a (miR-23a) in peripheral blood and pH value in exhaled breath condensate (EBC) will be measured, lung spirometry will be tested in the first, second, and fourth years. Primary outcome is the incidence of COPD, multivariate regression analysis will be used to establish the predictive model for COPD in China.

Discussion

With the rapid decline of lung function as the core and the baseline inflammatory biomarkers in peripheral blood and pH of the exhaled breath condensate as affecting factors, a predictive model to achieve early detection of high-risk COPD groups will be established and promoted.

Trial registration

This study has been registered at www.ClinicalTrials.gov (registration identifier: NCT03532893) on 21 May 2018, https://register.clinicaltrials.gov.

Serum inflammatory markers and nutritional status in patients with stable chronic obstructive pulmonary disease

Background

Chronic obstructive pulmonary disease (COPD) is a systemic inflammatory disease. We investigated whether serum inflammatory markers, C-reactive protein (CRP), leptin, and nutritional status (assessed by measurement of serum levels of prealbumin and anthropometry) correlated with COPD severity.

Materials and Methods

One-hundred and two COPD patients (mean age 56.94 ± 10.95 years) were recruited and classified into severity categories based on the GOLD guidelines. Serum concentrations of CRP, prealbumin, and leptin were measured. Anthropometry included body mass index (BMI), mid-upper arm circumference (MUAC), and sum of four skinfold thicknesses (triceps, biceps, suprailiac, and subscapular).

Results

Twenty-one patients had moderate, 44 had severe, and 37 had very severe COPD. Levels of CRP (mg/dl) (mean ± standard error [SE]) in moderate, severe, and very severe COPD were 0.60 ± 0.096, 2.16 ± 0.39, and 4.15 ± 0.463, respectively. Levels of prealbumin (mg/dl) (mean ± SE) in moderate, severe, and very severe COPD were 15.7 3 ± 0.92, 10.95 ± 0.85, and 11.15 ± 0.79 mg/dl, respectively. Levels of leptin (ng/ml) (mean ± SE) in moderate, severe, and very severe COPD were 13.81 ± 3.88, 8.45 ± 2.25, and 4.40 ± 1.06, respectively. BMI values in the three groups were 23.44 ± 1.16 kg/m², 20.33 ± 0.62 kg/m², and 18.86 ± 0.52 kg/m², respectively. Sum of four skinfold thickness and MUAC was significantly reduced in very severe group as compared to moderate and severe group. Very severe COPD patients had a significantly lower leptin, BMI, and 6-min walk test. Serum CRP was significantly higher in very severe COPD.

Conclusion

Patients with increasing severity of COPD had a significantly greater serum inflammatory marker level and poorer nutritional status.

Cytokines and statin therapy in chronic obstructive pulmonary disease patients

Cytokines are biological response modifiers involved in the pathophysiology of chronic obstructive pulmonary disease (COPD). This study investigated the potential use of cytokines as disease severity biomarkers in COPD patients and the possible effect of statin therapy on cytokine expression. Possible associations between cytokines, body mass index (BMI) and smoking have also been studied. Cytokines IFN-γ, IL-2, IL-12 p70, TNF-α, TNF-β, IL-4, IL-5, IL-6, IL-10, IL-1β and IL-8 were measured in the plasma of 100 clinically stable COPD patients using a fluorescent bead immunoassay on a flow cytometer. When patients were grouped according to Global Initiative for Chronic Obstructive Lung Disease (GOLD) stage (A-D), no significant differences in cytokine concentrations were found (p > .05). Significantly decreased concentrations of IL-1β, IL-2, IL-4, IL-8, IL-10, IL-12p70 and TNF-α were found in COPD patients receiving statin therapy in comparison with COPD patients not receiving statin therapy (p < .05). COPD patients with increased BMI (>25) had decreased IL-2 (p=.038), IL-8 (p = .039) and IL-10 (p = .005) concentrations compared to normal BMI (20-25) patients. Current COPD smokers had increased concentrations of IL-5 (p = .037) compared to former COPD smokers. Hierarchical cluster analysis showed several patterns of measured cytokines in serum of patients with stable COPD. Statin therapy is associated with decreased expression of selected Th1 and Th2 cytokines in COPD, and this effect could be of relevance in COPD patients with increased cardiovascular risk. Concentrations of Th1 and Th2 cytokines in plasma cannot be used as biomarkers of disease severity or progression of COPD.

Association of Adiponectin with Lung Function Impairment and Disease Severity in Chronic Obstructive Pulmonary Disease

Context:

Chronic obstructive pulmonary disease (COPD) is not only restricted to the pulmonary inflammation and airway obstruction but is also associated with comorbidities, which affect the therapeutic intervention and the quality of life and survival. Markers that can predict the systemic inflammation and a decline in the pulmonary function are of scientific interest. Adiponectin (APN) appears to be one such biomarker and can be used as a potential indicator of severity and response to treatment in patients of COPD.

Aims:

The study aims to find out the role of APN as a marker of inflammation in the pathogenesis of COPD and explore its relationship with the severity of the disease.

Settings and Design:

This was a cross-sectional study.

Subjects and Methods:

The study group consisted of 60 patients of COPD, which included 30 males admitted with acute exacerbation of COPD (AECOPD) and 30 males with stable COPD. The study group was compared with 30 healthy, age-matched males. APN was estimated by commercially available ELISA kits. Pulmonary function tests were performed on all cases and controls using standardized protocols on SPIROLAB III.

Statistical Analysis Used:

Statistical analysis was performed using Student's t-test and Pearson's correlation coefficient.

Results:

The levels of APN were found to be significantly higher in patients with COPD as compared to the controls and the levels increased with the severity of the disease were 16.10 ± 4.97 ng/ml and 11.43 ± 4.22 ng/ml, respectively, in AECOPD and COPD. A significant positive correlation was found between the levels of APN and interleukin (IL)-8 in patients of COPD, while the levels correlated negatively with percentage of forced expiratory volume in 1 s (FEV1%).

Conclusions:

The results reveal that APN is associated with the inflammatory process of COPD as suggested by its significant inverse relationship with FEV1% and positive correlation with a marker of inflammation such as IL-8. It can thus be used as a biomarker for disease severity and progression in patients of COPD, therefore aiding in risk stratification and therapeutic intervention.

Activating transcription factor 3 represses cigarette smoke-induced IL6 and IL8 expression via suppressing NF-κB activation

Airway and lung inflammation is a fundamental hallmark of chronic obstructive pulmonary disease (COPD). Activating transcription factor 3 (ATF3) has been reported to negatively regulate many pro-inflammatory cytokines and chemokines. However, little is known about the impact of ATF3 on the inflammatory response of COPD. Since cigarette smoke (CS) is considered to be the most important risk factor in the etiology of COPD, we attempted to investigate the effects and molecular mechanisms of ATF3 in CS-induced inflammation. We observed an increase in the expression of ATF3 in the lung tissues of CS-exposed mice and CS extract (CSE)-treated human bronchial epithelial (HBE) cells. In vitro results indicated that ATF3 inhibition significantly increased the expression of proinflammatory cytokines interleukin 6 (IL6) and interleukin 8 (IL8) in CSE-stimulated HBE cells. Furthermore, in vivo data verified that CS induced inflammatory cell recruitment around the bronchus. In addition, neutrophil infiltration in bronchoalveolar lavage fluid (BALF) of CS-exposed Atf3^-/- mice was markedly higher than in stimulated WT mice. Finally, ATF3 deficiency increased the in vitro and in vivo expression and phosphorylation of nuclear factor-κB (NF-κB), a positive mediator of inflammation. Thus, this study shows that ATF3 plays an important role in the negative regulation of CS-induced pro-inflammatory gene expression through downregulating NF-κB phosphorylation.

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

Rationale

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

Methods

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

Results

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

Conclusion

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

Is the COPD assessment test (CAT) effective in demonstrating the systemic inflammation and other components in COPD?

INTRODUCTION

Chronic obstructive pulmonary disease (COPD) is currently a complex, multicomponent disorder. The COPD Assessment Test (CAT) has been increasingly used to assess COPD patients. This study aims to investigate the relationship between CAT and inflammation markers and other COPD components.

METHODS

We enrolled 110 stable COPD patients and 65 control subjects in this study. All patients completed the CAT questionnaire and the modified Medical Research Council (mMRC) dispnea scale. The quality of life of these patients was measured with St. George's Respiratory Questionnaire (SGRQ). Levels of TNFα, IL-6, CRP were determined in blood samples.

RESULTS

In COPD patients, serum levels of TNFα (109.5 ± 58 pg/ml), IL-6 (10.3 ± 18 pg/ml), and C-reactive protein (CRP) (1.6 ± 1.7 mg/L) were found to be significantly higher compared to controls (TNF-α: 14.6 ± 18 pg/ml, IL-6: 2.14 ± 1.9 pg/ml, CRP: 0.4 ± 0.3mg/L, p<0.001). These markers were correlated with smoking (r from 0.27 to 0.35, p<0.001), FEV1 (r from -0.39 to -0.57, p<0.001), FVC (r from -0.32 to -0.37, p<0.001) and FEV1/FVC (r from -0.31 to -0.66, p<0.001). The CAT score correlated with GOLD spirometric stages, mMRC dyspnea score, number of exacerbations in the previous year and FEV1 (p<0.001). There was a significant correlation between levels of CRP and the CAT score (r=0.43, p<0.001) but no similar relationship between levels of TNFα and IL-6 and the CAT was observed.

CONCLUSION

Systemic inflammation persists in the stable period of COPD. CRP, one of the inflammation markers, was correlated with the CAT. Further studies are required to confirm the relationship between CAT and biomarkers.

Role of Serum Interleukin 6, Albumin and C-Reactive Protein in COPD Patients

BACKGROUND

Chronic obstructive pulmonary disease (COPD) is a non-specific inflammation, which involves the airways, lung parenchyma and pulmonary vessels. The inflammation causes the activation of inflammatory cells and the release of various inflammatory mediators such as interleukin-8 (IL-8), IL-6 and tumor necoris factor alpha (TNF-a). The purpose of the present study was to measure serum IL-6, C-reactive protein (CRP) (as a positive phase reactant) and albumin level (as a negative phase reactant) in COPD patients (only due to cigarette smoking not bio-mass), non COPD smokers and healthy subjects using enzyme-linked immunosorbent assay (ELISA); we compared the differences in inflammatory factors among groups.

MATERIALS AND METHODS

A total of 180 males were enrolled in this study and divided into three equal groups. The first group was 60 smokers who had COPD. The second group included 60 smokers without COPD and the third group consisted of people who were not smokers and did not have COPD; 5 mL of venous blood was taken from all participants and it was collected in a test tube containing anticoagulant and then centrifuged at 3000 rpm for 10 minutes. Serum was separated and used to measure the amount of IL-6, CRP and albumin. Spirometry was performed according to the criteria set by the American Thoracic Society.

RESULTS

The mean serum level of IL-6 was 83.2±7.5 pg/mL in group I, 54.9±24.3 pg/mL in group II and 46.9±10.4 pg/mL in group III. There was a significant difference among the three groups (P<0.001). The mean serum level of CRP was 28.9±14.9 mg/dL in the first group, 19.9±8.5 mg/dL in the second group and 4.2±2.3 mg/dL in the third group (P=0.02). But by controlling the confounding effects of age, this difference was not significant (P=0.49). The mean serum level of albumin was I 4.1±0.57 mg/dL in group I, 4.3±0.56 mg/dL in group II and 4.1±0.53 mg/dL in group III. There was no significant difference among the three groups in this regard (P=0.099).There was a significant inverse relationship between serum levels of IL-6 and FEV 1 (r=-0.341, P<0.001). Moreover, there was a significant inverse relationship between serum levels of IL-6 and FEV1/FVC (r=-0.309, P<0.001). Serum albumin level was not different among various stages. Level of CRP and IL6 increased as the stage of COPD got worse in smokers.

CONCLUSION

Our study showed that serum level of IL-6 predicts development of COPD in smokers with a high sensitivity among all inflammatory factors namely CRP, IL-6, and albumin.

Genetic variations in RORα are associated with chronic obstructive pulmonary disease

Retinoic acid receptor-related orphan receptor-α (RORα) plays a key role in the regulation of lipid and cholesterol metabolism that has been implicated in the development of chronic obstructive pulmonary disease (COPD). The aim of this study was to determine the frequencies of single-nucleotide polymorphisms (SNPs) in RORα gene in a Chinese population and their possible association with COPD susceptibility. Nine tagging SNPs, including rs17270181, rs1898413, rs17270216, rs8033552, rs8036966, rs7169364, rs340002, rs340023 and rs11630262, were screened in 279 COPD patients and 367 controls by the SNaPshot method. Association analysis of genotypes and haplotypes constructed from these loci with COPD was conducted under different genetic models. Alleles or genotypes of rs8033552 distributed significantly differently in COPD patients and controls (allele: P=0.0001, false discovery rate (FDR) Q=0.004, odds ratios (OR): 1.62 and 95% confidence interval (CI): 1.27-2.07; genotype: P=0.0005, FDR Q=0.008). The allele A at rs8033552 was potentially associated with an increased risk of COPD in additive model, displaying ORs of 1.62 (95% CI: 1.17-2.26, P=0.004, FDR Q=0.019) in subjects with genotypes AG vs GG and 2.69 (95% CI: 1.47-4.93, P=0.001, FDR Q=0.011) in subjects with genotypes AA vs GG, respectively. In haplotype analysis, we observed haplotypes GGAGATGTG and GGAGCTGTG had protective effects, whereas haplotypes GGAGATACA and GGAGATACG were significantly associated with the increased risk of COPD. These data suggest that RORα may be a potential risk gene for COPD.

Plasma cytokine profiles related to smoking-sensitivity and phenotypes of chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) develops only in smoking-sensitive smokers and manifests heterogeneous phenotypes, including emphysema and non-emphysema types. We aimed to identify biomarkers related to the smoking-sensitivity and phenotypes of COPD. Among 240 smokers suggestive of COPD, we studied on four groups defined by % forced expiratory volume in one second (FEV1) and computed tomography-based pulmonary emphysema. Plasma concentrations of 33 inflammatory markers were measured in four groups as well as Non-smokers using multiplex protein arrays. IL-5, IL-7 and IL-13 were identified to be associated with smoking sensitivity and IL-6 and IL-10 were candidate biomarkers for airway-lesion dominant COPD.

Cytokine inhibition in the treatment of COPD

Cytokines play an important part in many pathobiological processes of chronic obstructive pulmonary disease (COPD), including the chronic inflammatory process, emphysema, and altered innate immune response. Proinflammatory cytokines of potential importance include tumor necrosis factor (TNF)-α, interferon-γ, interleukin (IL)-1β, IL-6, IL-17, IL-18, IL-32, and thymic stromal lymphopoietin (TSLP), and growth factors such as transforming growth factor-β. The current objectives of COPD treatment are to reduce symptoms, and to prevent and reduce the number of exacerbations. While current treatments achieve these goals to a certain extent, preventing the decline in lung function is not currently achievable. In addition, reversal of corticosteroid insensitivity and control of the fibrotic process while reducing the emphysematous process could also be controlled by specific cytokines. The abnormal pathobiological process of COPD may contribute to these fundamental characteristics of COPD, and therefore targeting cytokines involved may be a fruitful endeavor. Although there has been much work that has implicated various cytokines as potentially playing an important role in COPD, there have been very few studies that have examined the effect of specific cytokine blockade in COPD. The two largest studies that have been reported in the literature involve the use of blocking antibody to TNFα and CXCL8 (IL-8), and neither has provided benefit. Blocking the actions of CXCL8 through its CXCR2 receptor blockade was not successful either. Studies of antibodies against IL-17, IL-18, IL-1β, and TSLP are currently either being undertaken or planned. There is a need to carefully phenotype COPD and discover good biomarkers of drug efficacy for each specific target. Specific groups of COPD patients should be targeted with specific anticytokine therapy if there is evidence of high expression of that cytokine and there are features of the clinical expression of COPD that will respond.

Three-year follow-up of Interleukin 6 and C-reactive protein in chronic obstructive pulmonary disease

BACKGROUND

Past studies have shown that mean values of Interleukin-6 (IL-6) and C-reactive protein (CRP) do not change significantly in COPD patients over a one-year period. However, longer period follow-up studies are still lacking. Thus, the aim of this study is to evaluate plasma CRP and IL-6 concentration over three years in COPD patients and to test the association between these inflammatory mediators and disease outcome markers.

METHODS

A cohort of 77 outpatients with stable COPD was evaluated at baseline, and 53 (mean FEV1, 56% predicted) were included in the prospective study. We evaluated Interleukin-6 (IL-6), C-reactive protein (CRP), six-minute walking distance (6MWD), and body mass index (BMI) at baseline and after three years. Plasma concentration of IL-6 was measured by high sensitivity ELISA, and CRP was obtained by high sensitivity particle-enhanced immunonephelometry.

RESULTS

IL-6 increased significantly after 3 years compared to baseline measurements [0.8 (0.5-1.3) vs 2.4 (1.3-4.4) pg/ml; p < 0.001] and was associated with worse 6MWD performance. In the Cox regression, increased IL-6 at baseline was associated with mortality [Hazard Ratio (95% CI) = 2.68 (0.13, 1.84); p = 0.02]. CRP mean values did not change [5 (1.6-7.9) vs 4.7 (1.7-10) pg/L; p = 0.84], although eleven patients (21%) presented with changes >3 mg/L in CRP after 3 years.

CONCLUSIONS

The systemic inflammatory process, evaluated by IL-6, seems to be persistent, progressive and associated with mortality and worse physical performance in COPD patients.

TRIAL REGISTRATION

No.:NCT00605540.

Genetic variations in ADIPOQ gene are associated with chronic obstructive pulmonary disease

BACKGROUND

Adiponectin is reported to be related to the development of chronic obstructive pulmonary disease (COPD). Genetic variants in the gene encoding adiponectin (ADIPOQ) have been reported to be associated with adiponectin level in several genome-wide linkage and association studies. However, relatively little is known about the effects of ADIPOQ gene variants on COPD susceptibility. We determined the frequencies of single-nucleotide polymorphisms (SNPs) in ADIPOQ in a Chinese Han population and their possible association with COPD susceptibility.

METHODS

We conducted a case-control study of 279 COPD patients and 367 age- and gender-distribution-matched control subjects. Seven tagging SNPs in ADIPOQ, including rs710445, rs16861205, rs822396, rs7627128, rs1501299, rs3821799 and rs1063537 were genotyped by SNaPshot. Association analysis of genotypes/alleles and haplotypes constructed from these loci with COPD was conducted under different genetic models.

RESULTS

The alleles or genotypes of rs1501299 distributed significantly differently in COPD patients and controls (allele: P = 0.002, OR = 1.43 and 95%CI = 1.14-1.79; genotype: P = 0.008). The allele A at rs1501299 was potentially associated with an increased risk of COPD in all dominant model analysis (P = 0.009; OR: 1.54; 95%CI: 1.11-2.13), recessive model analyses (P = 0.015; OR: 1.75; 95% CI: 1.11-2.75) and additive model analyses (P = 0.003; OR: 2.11; 95% CI: 1.29-3.47). In haplotype analysis, we observed haplotypes AAAAACT and GGACCTC had protective effects, while haplotypes AGAACTC, AGGCCTC, GGAACTC, GGACACT and GGGCCTC were significantly associated with the increased risk of COPD.

CONCLUSIONS

We conducted the first investigation of the association between the SNPs in ADIPOQ and COPD risk. Our current findings suggest that ADIPOQ may be a potential risk gene for COPD. Further studies in larger groups are warranted to confirm our results.

The neutrophilic inflammatory phenotype is associated with systemic inflammation in asthma

BACKGROUND

The role of systemic inflammation in asthma is unclear. The aim of this study was to compare systemic inflammation in subjects with stable asthma, categorized by airway inflammatory phenotype, with healthy control subjects.

METHODS

Adults with stable asthma (n = 152) and healthy control subjects (n = 83) underwent hypertonic saline challenge and sputum induction. Differential leukocyte counts were performed on selected sputum. Plasma high-sensitivity C-reactive protein (CRP), IL-6, and tumor necrosis factor-α levels and sputum IL-8 and neutrophil elastase levels were determined by enzyme-linked immunosorbent assay. Sputum IL-8 receptor α (IL-8RA) and IL-8 receptor β (IL-8RB) messenger RNA expression were determined by real-time polymerase chain reaction.

RESULTS

Subjects with asthma were classified as having nonneutrophilic asthma or neutrophilic asthma. The asthma (neutrophilic) group had increased systemic inflammation compared with the asthma (nonneutrophilic) and healthy control groups, with median (interquartile range) CRP levels of 5.0 (1.6-9.2), 1.8 (0.9-5.3), and 1.8 (0.8-4.1) mg/L (P = .011), respectively, and IL-6 levels of 2.1 (1.5-3.1), 1.4 (1.0-2.1), and 1.1 (0.8-1.5) pg/mL (P < .001), respectively. The proportion of subjects with elevated CRP and IL-6 levels was also higher in the asthma (neutrophilic) group. Sputum IL-8 and neutrophil elastase protein and IL-8RA and IL-8RB gene expression were significantly increased in the asthma (neutrophilic) group. In multiple regression analysis of subjects with asthma, sex, BMI, statin use, and percent sputum neutrophils were significant predictors of log(10)CRP. Sex, BMI, and %FEV(1) were significant predictors of log(10)IL-6.

CONCLUSIONS

Systemic inflammation is increased in patients with asthma with neutrophilic airway inflammation and associated with worse clinical outcomes. Systemic inflammation may contribute to the pathophysiology of neutrophilic asthma.

[Characteristics of stable chronic obstructive pulmonary disease related to systemic inflammation]

BACKGROUND AND OBJECTIVE

Chronic obstructive pulmonary disease (COPD) is characterized by a systemic inflammation. The aim of this study was to evaluate the association between systemic inflammation, measured with C reactive protein (CRP), and clinical and functional outcomes of the disease.

PATIENTS AND METHODS

A randomized sample of 413 COPD patients from 31 primary health care centers of Barcelona was evaluated. Medical history, anthropometric measurements, toxic habits, treatments, Chronic Respiratory Questionnaire (CRQ) and dyspnea were registered. Spirometry, exhaled CO concentration and CRP in capillary blood were performed.

RESULTS

Median (standard deviation) of the age was 72 (8.4) years and forced expiratory volume in one second (FEV(1)) postbronchodilatador 1.65 (0.65) l. The correlation was negative between CRP and FEV(1) postbronchodilatador(r=-0.25, P<0.001) and between CRP and CRQ scores (r=-0.098, P=0.048) and positive between CRP and CO (r=0.1, P=0.039). The ratio of patients with elevated CRP was higher in advanced GOLD stage (P<0.001), worst dyspnea (P=0.042), patients treated with inhaled corticosteroids (P=0.018) and if they had been hospitalized during the last year (P=0.026). The multivariant analysis showed, as independent factors of elevated CRP, FEV(1) postbronchodilator and CO concentration.

CONCLUSION

In COPD patients, active smoking habit and the airway's obstruction degree are associated with a greater intensity of the inflammatory systemic response measured by the CRP.

Systemic inflammation and comorbidities in chronic obstructive pulmonary disease

The relationship between systemic inflammation and comorbidities in patients with chronic obstructive pulmonary disease (COPD) is unclear. This article discusses (1) the prevalence and clinical impact of comorbidities in COPD; (2) the current knowledge on definition, prevalence, consequences, and treatment of systemic inflammation in COPD; and (3) the relationship of systemic inflammation and lung cancer in COPD.

Persistent systemic inflammation is associated with poor clinical outcomes in COPD: a novel phenotype

Background

Because chronic obstructive pulmonary disease (COPD) is a heterogeneous condition, the identification of specific clinical phenotypes is key to developing more effective therapies. To explore if the persistence of systemic inflammation is associated with poor clinical outcomes in COPD we assessed patients recruited to the well-characterized ECLIPSE cohort (NCT00292552).

Methods and Findings

Six inflammatory biomarkers in peripheral blood (white blood cells (WBC) count and CRP, IL-6, IL-8, fibrinogen and TNF-α levels) were quantified in 1,755 COPD patients, 297 smokers with normal spirometry and 202 non-smoker controls that were followed-up for three years. We found that, at baseline, 30% of COPD patients did not show evidence of systemic inflammation whereas 16% had persistent systemic inflammation. Even though pulmonary abnormalities were similar in these two groups, persistently inflamed patients during follow-up had significantly increased all-cause mortality (13% vs. 2%, p<0.001) and exacerbation frequency (1.5 (1.5) vs. 0.9 (1.1) per year, p<0.001) compared to non-inflamed ones. As a descriptive study our results show associations but do not prove causality. Besides this, the inflammatory response is complex and we studied only a limited panel of biomarkers, albeit they are those investigated by the majority of previous studies and are often and easily measured in clinical practice.

Conclusions

Overall, these results identify a novel systemic inflammatory COPD phenotype that may be the target of specific research and treatment.

Decreased soluble dipeptidyl peptidase IV activity as a potential serum biomarker for COPD

OBJECTIVES

The objective of this study was to measure soluble dipeptidyl peptidase IV (sDPPIV) activity in sera of patients with stable chronic obstructive pulmonary disease (COPD) in comparison to healthy controls. The main goal was to assess changes in the enzyme activity in relation to severity of the disease, age and smoking history and to evaluate diagnostic accuracy for prediction of COPD by level of serum sDPPIV activity.

DESIGN AND METHODS

The study included 106 patients with stable COPD (GOLD II-GOLD IV stages) and 38 healthy controls. Serum sDPPIV activity as well as some inflammatory markers (CRP, total and differential leukocyte counts) was measured. Multivariate logistic regression models were applied to analyze association of sDPPIV activity and inflammatory markers in risk estimation for COPD development.

RESULTS

sDPPIV activity in COPD patients was significantly reduced when compared to healthy controls. Decrease was observed already in GOLD II stage. Age and smoking history did not influence sDPPIV activity. Very good diagnostic accuracy (AUC=0.833; sensitivity and specificity of 85.7% and 78.9%, respectively) for GOLD II and good diagnostic accuracy (AUC=0.801; sensitivity and specificity of 65.1% and 86.8%, respectively) for total cohort of COPD patients were found. The multivariate logistic regression model showed that the use of sDPPIV in combination with CRP and lymphocyte proportion improved diagnostic strength and gave an AUC of 0.933.

CONCLUSIONS

sDPPIV activity is decreased in COPD patients as early as in GOLD II stage. Very good diagnostic accuracy of sDPPIV activity suggests it as a candidate biomarker for early diagnosis of COPD.

COPD association and repeatability of blood biomarkers in the ECLIPSE cohort

Background

There is a need for biomarkers to better characterise individuals with COPD and to aid with the development of therapeutic interventions. A panel of putative blood biomarkers was assessed in a subgroup of the Evaluation of COPD Longitudinally to Identify Surrogate Endpoints (ECLIPSE) cohort.

Methods

Thirty-four blood biomarkers were assessed in 201 subjects with COPD, 37 ex-smoker controls with normal lung function and 37 healthy non-smokers selected from the ECLIPSE cohort. Biomarker repeatability was assessed using baseline and 3-month samples. Intergroup comparisons were made using analysis of variance, repeatability was assessed through Bland-Altman plots, and correlations between biomarkers and clinical characteristics were assessed using Spearman correlation coefficients.

Results

Fifteen biomarkers were significantly different in individuals with COPD when compared to former or non-smoker controls. Some biomarkers, including tumor necrosis factor-α and interferon-γ, were measurable in only a minority of subjects whilst others such as C-reactive protein showed wide variability over the 3-month replication period. Fibrinogen was the most repeatable biomarker and exhibited a weak correlation with 6-minute walk distance, exacerbation rate, BODE index and MRC dyspnoea score in COPD subjects. 33% (66/201) of the COPD subjects reported at least 1 exacerbation over the 3 month study with 18% (36/201) reporting the exacerbation within 30 days of the 3-month visit. CRP, fibrinogen interleukin-6 and surfactant protein-D were significantly elevated in those COPD subjects with exacerbations within 30 days of the 3-month visit compared with those individuals that did not exacerbate or whose exacerbations had resolved.

Conclusions

Only a few of the biomarkers assessed may be useful in diagnosis or management of COPD where the diagnosis is based on airflow obstruction (GOLD). Further analysis of more promising biomarkers may reveal utility in subsets of patients. Fibrinogen in particular has emerged as a potentially useful biomarker from this cohort and requires further investigation.

Trial Registration

SCO104960, clinicaltrials.gov identifier NCT00292552

[COPD and inflammation: statement from a French expert group. Phenotypes related to inflammation]

INTRODUCTION

The objective of the present article is to review available data on possible links between phenotypes and inflammatory profiles in patients with chronic obstructive pulmonary disease (COPD).

BACKGROUND

Chronic bronchitis is associated with proximal bronchial inflammation and small airway inflammation with remodeling at the site of obstruction. CT scanning enables patients to be phenotyped according to the predominantly bronchial or emphysematous nature of the morphological abnormality. Exacerbations, in a context of persistently elevated baseline inflammation, are associated with increased inflammation and a poor prognosis. Long-term studies have correlated inflammatory markers (and anti-inflammatory drug effects) with dynamic hyperinflation, possibly confirming that inflammation promotes hyperinflation. The inflammatory cell count in the pulmonary arterial walls correlates with the severity of endothelial dysfunction. The risk of developing pulmonary hypertension would seem to increase with low-grade systemic inflammation. The role of low-grade systemic inflammation in COPD co-morbidities, and in nutritional and muscular involvement in particular, remains a matter of debate. Regular physical exercise may help reduce this inflammation.

CONCLUSIONS

In COPD, many aspects of the clinical phenotype are related to inflammation. Better knowledge of these relationships could help optimize current and future treatments.

Biomarkers of systemic inflammation and depression and fatigue in moderate clinically stable COPD

INTRODUCTION

COPD is an inflammatory disease with major co-morbidities. It has recently been suggested that depression may be the result of systemic inflammation. We aimed to explore the association between systemic inflammation and symptoms of depression and fatigue in patients with mainly moderate and clinically stable COPD using a range of inflammatory biomarkers, 2 depression and 2 fatigue scales.

METHOD

We assessed 120 patients with moderate COPD (FEV1% 52, men 62%, age 66). Depression was assessed using the BASDEC and CES-D scales. Fatigue was assessed using the Manchester COPD-fatigue scale (MCFS) and the Borg scale before and after 6MWT. We measured systemic TNF-α, CRP, TNF-α-R1, TNF-α-R2 and IL-6.

RESULTS

A multivariate linear model of all biomarkers showed that TNF-α only had a positive correlation with BASDEC depression score (p = 0.007). TNF-α remained positively correlated with depression (p = 0.024) after further adjusting for TNF-α-R1, TNF-α-R2, 6MWD, FEV1%, and pack-years. Even after adding the MCFS score, body mass and body composition to the model TNF-α was still associated with the BASDEC score (p = 0.044). Furthermore, patients with higher TNF-α level (> 3 pg/ml, n = 7) had higher mean CES-D depression score than the rest of the sample (p = 0.03). Borg fatigue score at baseline were weakly correlated with TNF-α and CRP, and with TNF-α only after 6MWT. Patients with higher TNF-α had more fatigue after 6MWD (p = 0.054).

CONCLUSION

This study indicates a possible association between TNF-α and two frequent and major co-morbidities in COPD; i.e., depression and fatigue.

Circulating levels of inflammatory markers and mammographic density among postmenopausal women

Mammographic density is strongly associated with breast cancer risk. Inflammation is involved in breast carcinogenesis, perhaps through effects on mammographic density. We evaluated associations between inflammatory markers interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), and C-reactive protein (CRP) and mammographic density among postmenopausal women. Plasma IL-6, TNF-α, and CRP levels were measured in 145 women with benign breast disease (benign controls) and 397 women with a negative screening mammogram (well controls) enrolled in the Mammograms and Masses Study. Associations between the inflammatory markers and mammographic density were evaluated separately for benign and well controls through correlation analyses and linear regressions. Age-adjusted mean CRP levels were higher among benign controls (2.07 μg/ml) compared to well controls (1.63 μg/ml; P = 0.02), while IL-6 and TNF-α levels were similar between groups. Using linear regression, IL-6, TNF-α, and CRP were not statistically significantly associated with dense breast area within either group. Statistically significant positive associations were observed between all three markers and nondense breast area in both groups; statistically significant negative associations were observed between IL-6 and percent density among benign controls, and between all three markers and percent density among well controls. These associations were all attenuated and non-significant upon adjustment for body mass index. IL-6, TNF-α, and CRP levels were not independently associated with dense breast area, nondense breast area, or percent density in this study population. Our results suggest that these inflammatory factors do not impact breast carcinogenesis through independent effects on mammographic density.

Role of interleukin-6 in elastase-induced lung inflammatory changes in mice

Interleukin-6 (IL-6) is known to be involved in the pathogenesis of various inflammatory diseases, but its role in the development of pulmonary emphysema remains unclear. Wild-type (WT) and IL-6-deficient mice received either phosphate-buffered saline (PBS) or porcine pancreatic elastase (PPE) intratracheally. The development of emphysema was determined by measuring the mean linear intercept (Lm). The lung specimens were also subjected to immunohistochemistry for single-stranded DNA to detect apoptotic cells. Lung mechanics and airway responsiveness to inhaled methacholine were analyzed. Bronchoalveolar lavage (BAL) fluid was subjected to evaluation of inflammatory cell accumulation and cytokine measurement. PPE treatment caused significant increases in Lm and lung compliance, which was attenuated by IL-6 deficiency. The increases in apoptotic cells in the lung were attenuated in IL-6 null mice. Airway responsiveness was not affected by PPE challenge or IL-6 deficiency. Intratracheal PPE increased the cell counts in BAL fluid throughout the observation, which was suppressed in IL-6 null mice. In BAL fluid, PPE-induced increases in the levels of macrophage inflammatory protein (MIP)-1alpha and eotaxin were mitigated by IL-6 deficiency. PPE-induced up-regulation of matrix metalloproteinase (MMP)-12 in the lung was attenuated by IL-6 deficiency. These results indicate that IL-6 may play an important role in the development of elastase-induced lung inflammatory changes.

Systemic inflammation in chronic obstructive pulmonary disease: may adipose tissue play a role? Review of the literature and future perspectives

Chronic obstructive pulmonary disease (COPD) is a major cause of morbidity and mortality worldwide. Low-grade systemic inflammation is considered a hallmark of COPD that potentially links COPD to increased rate of systemic manifestations of the disease. Obesity with/without the metabolic syndrome and cachexia represent two poles of metabolic abnormalities that may relate to systemic inflammation. On one hand systemic inflammatory syndrome likely reflects inflammation in the lungs, i.e. results from lung-to plasma spillover of inflammatory mediators. On the other hand, obesity-related hypoxia results in local inflammatory response within adipose tissue per se, and may contribute to elevations in circulatory mediators by spillover from the adipose tissue to the systemic compartment. The extent to which systemic hypoxia contributes to the adipose tissue inflammation remains unknown. We assume that in patients with COPD and concurrent obesity at least three factors play a role in the systemic inflammatory syndrome: the severity of pulmonary impairment, the degree of obesity-related adipose tissue hypoxia, and the severity of systemic hypoxia due to reduced pulmonary functions. The present review summarizes the epidemiological and clinical evidence linking COPD to obesity, the role of adipose tissue as an endocrine organ, and the role of hypoxia in adipose tissue inflammation.