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

Association of platelet count with all-cause mortality and risk of cardiovascular and respiratory morbidity in stable COPD

Background

Platelet count is a prognostic indicator in the general population and elderly. Thrombocytosis during acute exacerbation of COPD (AECOPD) has been associated with mortality; however, the relationship between platelet count and mortality in stable COPD is unknown.

Methods

We performed post hoc secondary analysis on a subsample of 1797 patients in the Study to Understand Mortality and Morbidity in COPD (SUMMIT) who had blood samples drawn at baseline. Participants were current or former smokers, 40–80 years old with moderate COPD and history or increased risk of cardiovascular (CV) disease. The primary outcome was on and post-treatment all-cause mortality. Secondary outcomes included first-on-treatment moderate/severe AECOPD and on-treatment CV composite event (CV death, myocardial infarction, stroke, unstable angina and transient ischemic attack). Multivariable Cox proportional hazards models were used to investigate study endpoint associations with platelet count quintile grouping, continuous platelet count utilizing two-term fractional polynomials, and categories of low, normal and high platelet count (< 150, ≥150 to < 300, ≥300 × 10⁹/L).

Results

Patients were followed for 2.3 ± 0.9 years for vital status and 1.6 ± 1.1 years for morbidity endpoints during which 105 (5.8%) died, 651 (36.2%) experienced AECOPD (159 with severe AECOPD) and 86 (4.8%) experienced a CV event. A U-shaped association between platelet count and all-cause mortality was observed. Compared to the third quintile group (Q3) of platelet count, risk of death was increased in the lowest quintile group (Q1; hazard ratio [HR]: 1.73; 95% confidence interval [CI]: 0.93–3.23) and highest quintile group (Q5; HR: 1.66; 95%CI: 0.89–3.10), though point estimates were imprecise. Using clinical cutoffs, compared with normal platelet counts (≥150 to < 300 × 10⁹/L), risk of all-cause mortality was nominally increased among patients with thrombocytopenia (HR: 1.46; 95%CI: 0.81–2.64) and high platelet count (HR: 1.66; 95%CI: 0.96–2.86). Compared with Q3, CV events were nominally increased for Q5 (HR: 1.71; 95%CI: 0.83–3.49) and Q1 (HR: 1.41; 95%CI: 0.70, 2.85). There was no association between platelet count and AECOPD.

Conclusions

In stable COPD platelet count demonstrated a U-shaped association with increased risk of 3-year all-cause mortality, though a platelet count level above or below which risk of mortality was increased could not be definitively identified.

Trial registration

ClinicalTrials.gov NCT01313676.

Serum biomarkers and outcomes in patients with moderate COPD: a substudy of the randomised SUMMIT trial

Rationale

Systemic levels of C reactive protein (CRP), surfactant protein D (SPD), fibrinogen, soluble receptor of activated glycogen end-product (sRAGE) and club cell protein 16 (CC-16) have been associated with chronic obstructive pulmonary disease (COPD) outcomes. However, they require validation in different cohorts.

Objectives

Relate systemic levels of those proteins to forced expiratory volume in 1 s (FEV1) decline, exacerbations, hospitalisations and mortality in COPD patients (FEV1 of ≥50 and ≤70% predicted) and heightened cardiovascular risk in a substudy of the Study to Understand Mortality and MorbidITy trial.

Methods

Participants were randomised to daily inhalations of placebo, vilanterol 25 µg (VI), fluticasone furoate 100 µg (FF) or their combination (VI 25/FF 100) and followed quarterly until 1000 deaths in the overall 16 485 participants occurred. Biomarker blood samples were available from 1673 patients. The FEV1 decline (mL/year), COPD exacerbations, hospitalisations and death were determined. Associations between biomarker levels and outcomes were adjusted by age and gender.

Results

Systemic levels of CC-16, CRP, sRAGE, SPD and fibrinogen did not relate to baseline FEV1, FEV1 decline, exacerbations or hospitalisations. Fibrinogen and CRP were related to mortality over a median follow-up of 2.3 years. Only the CC-16 changed with study therapy (VI, FF and FF/VI, p<0.01) at 3 months.

Conclusions

In COPD, systemic levels of CC-16, CRP, sRAGE, SPD and fibrinogen were not associated with FEV1 decline, exacerbations or hospitalisations. These results cast doubts about the clinical usefulness of the systemic levels of these proteins as surrogate markers of these COPD outcomes. The study confirms that CRP and fibrinogen are associated with increased risk of death in patients with COPD.

Trial registration number

NCT01313676.

Identification of Putative Regulatory Alterations Leading to Changes in Gene Expression in Chronic Obstructive Pulmonary Disease

Various genetic and environmental factors are known to be associated with chronic obstructive pulmonary disease (COPD). We identified COPD-related differentially expressed genes (DEGs) using 189 samples accompanying either adenocarcinoma (AC) or squamous cell carcinoma (SC), comprising 91 normal and 98 COPD samples. DEGs were obtained from the intersection of two DEG sets separately identified for AC and SC to exclude the influence of different cancer backgrounds co-occurring with COPD. We also measured patient samples named group 'I', which were unable to be determined as normal or COPD based on alterations in gene expression. The Gene Ontology (GO) analysis revealed significant alterations in the expression of genes categorized with the 'cell adhesion', 'inflammatory response', and 'mitochondrial functions', i.e., well-known functions related to COPD, in samples from patients with COPD. Multi-omics data were subsequently integrated to decipher the upstream regulatory changes linked to the gene expression alterations in COPD. COPD-associated expression quantitative trait loci (eQTLs) were located at the upstream regulatory regions of 96 DEGs. Additionally, 45 previously identified COPD-related miRNAs were predicted to target 66 of the DEGs. The eQTLs and miRNAs might affect the expression of 'respiratory electron transport chain' genes and 'cell proliferation' genes, respectively, while both eQTLs and miRNAs might affect the expression of 'apoptosis' genes. We think that our present study will contribute to our understanding of the molecular etiology of COPD accompanying lung cancer.

Risk factors for lung cancer in COPD - results from the Bergen COPD cohort study

BACKGROUND

COPD patients have an increased risk of developing lung cancer, but the underlying mechanisms are poorly understood. We aimed to identify risk factors for lung cancer in patients from the Bergen COPD Cohort Study.

METHODS

We compared 433 COPD patients with 279 healthy controls, all former or current smokers. All COPD patients had FEV1<80% and FEV1/FVC-ratio<0.7. Baseline predictors were sex, age, spirometry, body composition, smoking history, emphysema assessed by CT, chronic bronchitis, prior exacerbation frequency, Charlson Comorbidity Score, inhalation medication and 44 serum/plasma inflammatory biomarkers. Patients were followed up for 9 years recording incidence of lung cancer. Cox-regression models were fitted for the statistical analyses. The biomarkers were evaluated using principal component analysis.

RESULTS

28 COPD patients and 3 controls developed lung cancer, COPD patients had a significantly higher risk of developing lung cancer, (HR 5.0; 95% CI 1.5-17.1, p < 0.01, adjusted values). Among COPD patients, emphysema (HR 4.4; 1.7-10.8, p < 0.01) and obesity (HR 3.3; 1.3-8.5, p = 0.02) were associated with a higher cancer rate. Use of inhaled steroids was associated with a lower rate (HR 0.4; 0.2-0.9, p = 0.03). Smoking status, pack-years smoked or levels of systemic inflammatory markers, except for interferon gamma-induced protein 10, did not affect the lung cancer rate in patients with COPD.

CONCLUSION

Patients with COPD have a higher lung cancer rate compared to healthy controls adjusted for smoking. The presence of emphysema and obesity in COPD predicted a higher lung cancer risk in COPD patients. Systemic inflammation was not associated with increased lung cancer risk.

Frailty trajectories in adult lung transplantation: A cohort study

BACKGROUND

Frailty is common in adults with advanced lung disease and is associated with death before and after lung transplantation. We aimed to determine whether frailty changes from before to after the lung transplant.

METHODS

In a single-center, prospective cohort study among adults undergoing lung transplantation from 2010 to 2017, we assessed frailty by the Short Physical Performance Battery (SPPB; higher scores reflect less frailty) and Fried Frailty Phenotype (FFP; higher scores reflect greater frailty) before and repeatedly up to 36 months after transplant. We tested for changes in frailty scores over time using segmented mixed effects models, adjusting for age, sex, and diagnosis. We quantified the proportion of subjects transitioning between frailty states (frail vs not frail) from before to after the transplant.

RESULTS

In 246 subjects, changes in frailty occurred within the first 6 post-operative months and remained stable thereafter. The overall change in frailty was attributable to improvements among those subjects who were frail before transplant. They experienced a 5.1-point improvement in SPPB (95% confidence interval [CI] 4.6-5.7) and a 1.8-point improvement in FFP (95% CI -2.1 to -1.6) during the early period. Frailty by SPPB and FFP did not change in those who were not frail before transplant. Approximately 84% of survivors who were frail before transplant became not frail after transplant.

CONCLUSIONS

Pre-operative frailty resolves in many patients after lung transplantation. Because a large proportion of frailty may be attributable to advanced lung disease, frailty alone should not be an absolute contraindication to transplantation.

Inference of Cellular Immune Environments in Sputum and Peripheral Blood Associated with Acute Exacerbations of COPD

Introduction

Chronic obstructive pulmonary disease (COPD) is the fourth leading cause of death in the United States, with high associated costs. Most of the cost burden results from acute exacerbations of COPD (AE-COPD), events associated with heightened symptoms and mortality. Cellular mechanisms underlying AE-COPD are poorly understood, likely because they arise from dysregulation of complex immune networks across multiple tissue compartments.

Methods

To gain systems-level insight into cellular environments relevant to exacerbation, we applied data-driven modeling approaches to measurements of immune factors (cytokines and flow cytometry) measured previously in two different human tissue environments (sputum and peripheral blood) during the stable and exacerbated state.

Results

Using partial least squares discriminant analysis, we identified a unique signature of cytokines in serum that differentiated stable and AE-COPD better than individual measurements. Furthermore, we found that models integrating data across tissue compartments (serum and sputum) trended towards being more accurate. The resulting paracrine signature defining AE-COPD events combined elevations of proteins associated with cell adhesion (sVCAM-1, sICAM-1) and increased levels of neutrophils and dendritic cells in blood with elevated chemoattractants (IP-10 and MCP-2) in sputum.

Conclusions

Our results supported a new hypothesis that AE-COPD is driven by immune cell trafficking into the lung, which requires expression of cell adhesion molecules and raised levels of innate immune cells in blood, with parallel upregulated expression of specific chemokines in pulmonary tissue. Overall, this work serves as a proof-of-concept for using data-driven modeling approaches to generate new insights into cellular processes involved in complex pulmonary diseases.

The Economic Effect of Early Management in Patients with Early Chronic Obstructive Pulmonary Disease: Results from a Population-Based Nationwide Survey

PURPOSE

The economic effect of regular follow-up and early management in patients with early chronic obstructive pulmonary disease (COPD) has not yet been clarified. Therefore, this study aimed to estimate the economic effect of regular follow-up and early management in these patients.

METHODS

Patients with early COPD were identified from the Korea National Health and Nutrition Examination Survey. We analyzed medical utilization and cost for 2 years without any missing data by using the Korean National Health Insurance data. Patients with routine healthcare maintenance were defined as, after diagnosis, those with regular visits to the hospital and receiving early management of COPD.

RESULTS

Among 1204 patients with early COPD, the patients who were classified as the group with routine healthcare maintenance (69/146; 47.3%) and the group with intermittent healthcare user (79/1058; 7.5%) visited to hospital for the next 2 years. The patients with routine healthcare maintenance had lower cost of inpatient service and frequencies of emergency room (ER) visit and intensive care unit (ICU) admission than intermittent healthcare users (cost of inpatient service, $4595 vs. $4953 per person; ER visit, 7.2 vs. 11.5; ICU admission, 4.3 vs. 7.7). Even in patients with COPD and FEV₁ ≥ 80, early intervention through follow-up reduced the cost of inpatient service because these patients could have had less severe acute exacerbations than intermittent healthcare users.

CONCLUSION

Patients with early COPD, even those with FEV₁ ≥ 80, need regular follow-up for early management and disease control as well as for reducing the socioeconomic burden of the disease.

Rehabilitation in chronic respiratory diseases: In-hospital and post-exacerbation pulmonary rehabilitation

Exacerbations of chronic obstructive pulmonary disease (COPD) that require hospitalization are important events for patients. Functional impairment and skeletal muscle dysfunction can increase the risk of hospitalization and readmission, independent of lung function. In addition, once a patient is admitted, multiple factors can lead to worsening outcome including immobility, systemic inflammation and nutritional depletion. These non-pulmonary factors are potentially amenable to exercise therapy, as part of pulmonary rehabilitation (PR). Peri-exacerbation PR has an important role in the management of exacerbations of COPD. In this review, we explore how functional limitation and skeletal muscle dysfunction affect patients having a severe exacerbation of COPD, the systemic impact of hospitalization on patients including potential aetiologies and the role of PR around the time of an exacerbation. This includes rehabilitation during the inpatient phase, post-exacerbation rehabilitation and rehabilitation bridging hospital discharge. We also describe potential future developments in peri-exacerbation PR.

Soluble Urokinase-Type Plasminogen Activator Receptor and Arterial Stiffness in Patients with COPD

Introduction

Soluble urokinase-type plasminogen activator receptor (suPAR) is upregulated by inflammation and plays a role in the pathogenesis of atherosclerosis. Chronic obstructive pulmonary disease (COPD) is associated with enhanced systemic inflammation and increased risk for atherosclerosis, however, studies analysing the circulating suPAR levels in COPD are contradictory. The aim of the study was to investigate plasma suPAR concentrations together with markers of arterial stiffness in COPD.

Materials and Methods

Twenty-four patients with COPD and 18 non-COPD, control subjects participated in the study. Plasma suPAR was measured, together with lung volumes, symptom burden, exacerbation history, markers of arterial stiffness and soluble inflammatory biomarkers, such as endothelin-1, high-sensitivity C-reactive protein (hsCRP), interleukin-6 (IL-6).

Results

Plasma suPAR levels were higher in COPD (2.84 ± 0.67 ng/ml vs. 2.41 ± 0.57 ng/ml, p = 0.03) and were related to lung function measured with FEV₁ (r = − 0.65, p < 0.01) and symptom burden determined with the modified Medical Research Council questionnaire (r = 0.55, p < 0.05). Plasma suPAR concentrations correlated with various measures of arterial stiffness in all subjects, but only with ejection duration in COPD (r = − 0.44, p = 0.03).

Conclusions

Plasma suPAR levels are elevated in COPD and relate to arterial stiffness. Our results suggest that suPAR may be a potential link between COPD and atherosclerosis.

Systemic Markers of Inflammation in Smokers With Symptoms Despite Preserved Spirometry in SPIROMICS

BACKGROUND

Chronic respiratory symptoms and exacerbation-like events are common among ever-smokers without airflow limitation on spirometry. The pathobiology of respiratory disease in this subgroup remains poorly defined, but may be due to underlying inflammation that overlaps with COPD or asthma. We hypothesized that symptoms, exacerbations, and functional measures of disease severity among smokers with preserved spirometry would be associated with markers of systemic inflammation, similar to what is reported in bone fide COPD, rather than elevated type 2 inflammation, which is often present in asthma.

METHODS

We measured inflammatory markers associated with COPD (C-reactive protein [CRP], fibrinogen, soluble tumor necrosis factor receptors [sTNFRSF1A and sTNFRSF1B], and blood/sputum neutrophils) and type 2 inflammation (IgE and blood/sputum eosinophils) in smokers with preserved spirometry (postbronchodilator FEV₁/FVC ≥ 0.70) from the Subpopulations and Intermediate Outcome Measures In COPD Study (SPIROMICS). We evaluated the relationship of these markers with respiratory symptom burden (dichotomized by a COPD assessment test score cutoff of 10, diagnosis of chronic bronchitis), exacerbations, 6-minute walk distance, and lung function on the basis of FEV₁.

RESULTS

CRP was associated with increased symptom burden (on the basis of COPD assessment test score and diagnosis of chronic bronchitis) and a greater number of exacerbations in the year before study enrollment. sTNFRSF1A was associated with symptom burden on the basis of COPD assessment test score. CRP and sTNFRSF1A levels negatively correlated with 6-minute walk distance. IgE and eosinophils were not associated with these outcomes.

CONCLUSIONS

Markers of inflammation including CRP and sTNFRSF1A are enriched among symptomatic smokers with preserved spirometry, suggesting an overlap with the underlying pathophysiology of COPD.

Elevated serum Activin A in chronic obstructive pulmonary disease with skeletal muscle wasting

OBJECTIVE

Muscle wasting contributes to the reduced quality of life and increased mortality in chronic obstructive pulmonary disease (COPD). Muscle atrophy in mice with cachexia was caused by Activin A binding to ActRIIB. The role of circulating Activin A leading to muscle atrophy in COPD remains elusive.

METHODS

In the present study, we evaluated the relationship between serum levels of Activin A and skeletal muscle wasting in COPD patients. The expression levels of serum Activin A were measured in 78 stable COPD patients and in 60 healthy controls via ELISA, which was also used to determine the expression of circulating TNF-α levels. Total skeletal muscle mass (SMM) was calculated according to a validated formula by age and anthropometric measurements. The fat-free mass index (FFMI) was determined as the fat-free mass (FFM) corrected for body surface area.

RESULTS

Compared to the healthy controls, COPD patients had upregulated Activin A expression. The elevated levels of Activin A were correlated with TNF-α expression, while total SMM and FFMI were significantly decreased in COPD patients. Furthermore, serum Activin A expression in COPD patients was negatively associated with both FFMI and BMI.

CONCLUSION

The above results showed an association between increased circulating Activin A in COPD patients and the presence of muscle atrophy. Given our previous knowledge, we speculate that Activin A contributes to skeletal muscle wasting in COPD.

Aspirin Use and Respiratory Morbidity in COPD: A Propensity Score-Matched Analysis in Subpopulations and Intermediate Outcome Measures in COPD Study

BACKGROUND

Aspirin use in COPD has been associated with reduced all-cause mortality in meta-regression analysis with few equivocal studies. However, the effect of aspirin on COPD morbidity is unknown.

METHODS

Self-reported daily aspirin use was obtained at baseline from SPIROMICS participants with COPD (FEV₁/FVC < 70%). Acute exacerbations of COPD (AECOPD) were prospectively ascertained through quarterly structured telephone questionnaires up to 3 years and categorized as moderate (symptoms treated with antibiotics or oral corticosteroids) or severe (requiring ED visit or hospitalization). Aspirin users were matched one-to-one with nonusers, based on propensity score. The association of aspirin use with total, moderate, and severe AECOPD was investigated using zero-inflated negative binomial models. Linear or logistic regression was used to investigate the association with baseline respiratory symptoms, quality of life, and exercise tolerance.

RESULTS

Among 1,698 participants, 45% reported daily aspirin use at baseline. Propensity score matching resulted in 503 participant pairs. Aspirin users had a lower incidence rate of total AECOPD (adjusted incidence rate ratio [IRR], 0.78; 95% CI, 0.65-0.94), with similar effect for moderate but not severe AECOPD (IRR, 0.86; 95% CI, 0.63-1.18). Aspirin use was associated with lower total St. George's Respiratory Questionnaire score (β, -2.2; 95% CI, -4.1 to -0.4), reduced odds of moderate-severe dyspnea (modified Medical Research Council questionnaire score ≥ 2; adjusted odds ratio, 0.69; 95% CI, 0.51-0.93), and COPD Assessment Test score (β, -1.1; 95% CI, -1.9 to -0.2) but not 6-min walk distance (β, 0.7 m; 95% CI, -14.3 to 15.6).

CONCLUSIONS

Daily aspirin use is associated with reduced rate of COPD exacerbations, less dyspnea, and better quality of life. Randomized clinical trials of aspirin use in COPD are warranted to account for unmeasured and residual confounding.

TRIAL REGISTRY

ClinicalTrials.gov; No.: NCT01969344; URL: www.clinicaltrials.gov.

What are the best indicators to assess malnutrition in idiopathic pulmonary fibrosis patients? A cross-sectional study in a referral center

OBJECTIVES

Little is known about the indicators to assess malnutrition in patients with idiopathic pulmonary fibrosis (IPF). This study aimed to determine the following: 1) the prevalence of malnutrition in IPF patients; 2) the nutritional indicators predictive of low fat-free mass (FFM) as measured by bioimpedance analysis; 3) the IPF patients' characteristics associated with low FFM.

METHODS

The IPF patients were consecutively recruited in a referral center for rare pulmonary diseases. Malnutrition was defined as a fat-free mass index (FFMI) = FFM (kg) / (height [m]²) <17 (men) or <15 (women). Nutritional assessment included body mass index (BMI), mid-arm circumference (MAC), triceps skinfold thickness, analogue food intake scale, and serum albumin and transthyretin. The primary endpoint was FFMI. Area under the receiver operating characteristic curve (AUC) assessed low FFMI prediction from nutritional indicators. Multivariable logistic regression determined variables associated with low FFMI.

RESULTS

Eighty-one patients were consecutively recruited. Low FFMI prevalence was 28% (23 of 81). BMI AUC was 0.91 (95% confidence interval [CI], 0.84‒0.97) and MAC AUC was 0.85 (0.76‒0.94). Multivariable analysis associated BMI (odds ratio [OR] 0.26 [95% CI, 0.12-0.54], P = 0.0003), male sex (OR 0.02 [0.00-0.33], P = 0.005), and smoking (OR 0.10 [0.01-0.75], P = 0.024) with a lower risk of malnutrition.

CONCLUSIONS

Malnutrition occurred in nearly one-third of IPF patients. Malnutrition screening should become systematic based on BMI and MAC, which are good clinical indicators of low FFMI. We propose a practical approach to screen malnutrition in IPF patients.

COPD and Cardiovascular Disease

COPD is one of the major public health problems in people aged 40 years or above. It is currently the 4th leading cause of death in the world and projected to be the 3rd leading cause of death by 2020. COPD and cardiac comorbidities are frequently associated. They share common risk factors, pathophysiological processes, signs and symptoms, and act synergistically as negative prognostic factors. Cardiac disease includes a broad spectrum of entities with distinct pathophysiology, treatment and prognosis. From an epidemiological point of view, patients with COPD are particularly vulnerable to cardiac disease. Indeed, mortality due to cardiac disease in patients with moderate COPD is higher than mortality related to respiratory failure. Guidelines reinforce that the control of comorbidities in COPD has a clear benefit over the potential risk associated with the majority of the drugs utilized. On the other hand, the true survival benefits of aggressive treatment of cardiac disease and COPD in patients with both conditions have still not been clarified. Given their relevance in terms of prevalence and prognosis, we will focus in this paper on the management of COPD patients with ischemic coronary disease, heart failure and dysrhythmia.

The Role of Omega-3 Fatty Acids in the Setting of Coronary Artery Disease and COPD: A Review

Chronic obstructive pulmonary disease (COPD) is a growing healthcare concern and will represent the third leading cause of death worldwide within the next decade. COPD is the result of a complex interaction between environmental factors, especially cigarette smoking, air pollution, and genetic preconditions, which result in persistent inflammation of the airways. There is growing evidence that the chronic inflammatory state, measurable by increased levels of circulating cytokines, chemokines, and acute phase proteins, may not be confined to the lungs. Cardiovascular disease (CVD) and especially coronary artery disease (CAD) are common comorbidities of COPD, and low-grade systemic inflammation plays a decisive role in its pathogenesis. Omega-3 polyunsaturated fatty acids (n-3 PUFAs) exert multiple functions in humans and are crucially involved in limiting and resolving inflammatory processes. n-3 PUFAs have been intensively studied for their ability to improve morbidity and mortality in patients with CVD and CAD. This review aims to summarize the current knowledge on the effects of n-3 PUFA on inflammation and its impact on CAD in COPD from a clinical perspective.

Pattern of Cardiovascular Comorbidity in COPD in a Country with Low-smoking Prevalence: Results from Two-population-based Cohorts from Sweden

Cardiovascular diseases are the most common comorbidities in COPD, due to common risk factors such as smoking. The prevalence of current smokers in Sweden has decreased over four decades to around 10%. The aim of the present study was to investigate the prevalence, distribution and associations of cardiovascular comorbidities in COPD by disease severity in two large areas of Sweden, both with low-smoking prevalence. Data from clinical examinations in 2009-2012, including spirometry and structured interview, from two large-scale population studies, the West Sweden Asthma Study (WSAS) and the OLIN Studies in Northern Sweden, were pooled. COPD was defined using post-bronchodilator spirometry according to the fixed ratio FEV₁/FVC <0.70 and the lower limit of normal (LLN^5th percentile) of the ratio of FEV₁/FVC. Of the 1839 subjects included, 8.7% and 5.7% had COPD according to the fixed ratio and the LLN criterion. Medication for heart disease or hypertension among those with moderate-to-severe COPD was more common than among those without COPD (fixed ratio definition of COPD: 51% vs. 23%, p < 0.001; LLN definition: 42% vs. 24%, p = 0.002). After adjusting for known risk factors for COPD, including smoking, age, socio-economic status, and occupational exposure for gas, dust and fumes, only heart failure remained significantly, and independently, associated with COPD, irrespective of the definitions of COPD. Though a major decrease in smoking prevalence, the pattern of cardiovascular comorbidities in COPD still remains similar with previously performed studies in Sweden and in other Westernized countries as well.

N-glycosylation patterns of plasma proteins and immunoglobulin G in chronic obstructive pulmonary disease

BACKGROUND

Chronic obstructive pulmonary disease (COPD) is a complex condition, whose diagnosis requires spirometric assessment. However, considering its heterogeneity, subjects with similar spirometric parameters do not necessarily have the same functional status. To overcome this limitation novel biomarkers for COPD have been investigated. Therefore, we aimed to explore the potential value of N-glycans as COPD biomarkers and to examine the individual variation of plasma protein and immunoglobulin G (IgG) glycosylation profiles in subjects with COPD and healthy controls.

METHODS

Both the total plasma protein and IgG N-glycome have been profiled in the total of 137 patients with COPD and 95 matching controls from Croatia. Replication cohort consisted of 61 subjects with COPD and 148 controls recruited at another Croatian medical centre.

RESULTS

Plasma protein N-glycome in COPD subjects exhibited significant decrease in low branched and conversely, an increase in more complex glycan structures (tetragalactosylated, trisialylated, tetrasialylated and antennary fucosylated glycoforms). We also observed a significant decline in plasma monogalactosylated species, and the same change replicated in IgG glycome. N-glycans also showed value in distinguishing subjects in different COPD GOLD stages, where the relative abundance of more complex glycan structures increased as the disease progressed. Glycans also showed statistically significant associations with the frequency of exacerbations and demonstrated to be affected by smoking, which is the major risk factor for COPD development.

CONCLUSIONS

This study showed that complexity of glycans associates with COPD, mirroring also the disease severity. Moreover, changes in N-glycome associate with exacerbation frequency and are affected by smoking. In general, this study provided new insights into plasma protein and IgG N-glycome changes occurring in COPD and pointed out potential novel markers of the disease progression and severity.

Elevated circulating MMP-9 is linked to increased COPD exacerbation risk in SPIROMICS and COPDGene

BACKGROUND

Matrix metalloprotease 9 (MMP-9) is associated with inflammation and lung remodeling in chronic obstructive pulmonary disease (COPD). We hypothesized that elevated circulating MMP-9 represents a potentially novel biomarker that identifies a subset of individuals with COPD with an inflammatory phenotype who are at increased risk for acute exacerbation (AECOPD).

METHODS

We analyzed Subpopulations and Intermediate Outcome Measures in COPD Study (SPIROMICS) and Genetic Epidemiology of COPD (COPDGene) cohorts for which baseline and prospective data were available. Elevated MMP-9 was defined based on >95th percentile plasma values from control (non-COPD) sample in SPIROMICS. COPD subjects were classified as having elevated or nonelevated MMP-9. Logistic, Poisson, and Kaplan-Meier analyses were used to identify associations with prospective AECOPD in both cohorts.

RESULTS

Elevated MMP-9 was present in 95/1,053 (9%) of SPIROMICS and 41/140 (29%) of COPDGene participants with COPD. COPD subjects with elevated MMP-9 had a 13%-16% increased absolute risk for AECOPD and a higher median (interquartile range; IQR) annual AECOPD rate (0.33 [0-0.74] versus 0 [0-0.80] events/year and 0.9 [0.5-2] versus 0.5 [0-1.4] events/year for SPIROMICS and COPDGene, respectively). In adjusted models within each cohort, elevated MMP-9 was associated with increased odds (odds ratio [OR], 1.71; 95%CI, 1.00-2.90; and OR, 3.03; 95%CI, 1.02-9.01), frequency (incidence rate ratio [IRR], 1.45; 95%CI, 1.23-1.7; and IRR, 1.24; 95%CI, 1.03-1.49), and shorter time-to-first AECOPD (21.7 versus 31.7 months and 14 versus 21 months) in SPIROMICS and COPDGene, respectively.

CONCLUSIONS

Elevated MMP-9 was independently associated with AECOPD risk in 2 well-characterized COPD cohorts. These findings provide evidence for MMP-9 as a prognostic biomarker and potential therapeutic target in COPD.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT01969344 (SPIROMICS) and NCT00608764 (COPDGene).

FUNDING

This work was funded by K08 HL123940 to JMW; R01HL124233 to PJC; Merit Review I01 CX000911 to JLC; R01 (R01HL102371, R01HL126596) and VA Merit (I01BX001756) to AG. SPIROMICS (Subpopulations and Intermediate Outcomes in COPD Study) is funded by contracts from the NHLBI (HHSN268200900013C, HHSN268200900014C,HHSN268200900015C HHSN268200900016C, HHSN268200900017C, HHSN268200900018C, HHSN268200900019C, and HHSN268200900020C) and a grant from the NIH/NHLBI (U01 HL137880), and supplemented by contributions made through the Foundation for the NIH and the COPD Foundation from AstraZeneca/MedImmune; Bayer; Bellerophon Therapeutics; Boehringer-Ingelheim Pharmaceuticals Inc.; Chiesi Farmaceutici; Forest Research Institute Inc.; GlaxoSmithKline; Grifols Therapeutics Inc.; Ikaria Inc.; Novartis Pharmaceuticals Corporation; Nycomed GmbH; ProterixBio; Regeneron Pharmaceuticals Inc.; Sanofi; Sunovion; Takeda Pharmaceutical Company; and Theravance Biopharma and Mylan. COPDGene is funded by the NHLBI (R01 HL089897 and R01 HL089856) and by the COPD Foundation through contributions made to an Industry Advisory Board composed of AstraZeneca, Boehringer Ingelheim, GlaxoSmithKline, Novartis, Pfizer, Siemens, and Sunovion.

Defining the role of neutrophil-to-lymphocyte ratio in COPD: a systematic literature review

COPD is characterized by a pulmonary and systemic inflammatory process. Several authors have reported the elevation of multiple inflammatory markers in patients with COPD; however, their use in routine clinical practice has limitations. The neutrophil-to-lymphocyte ratio (NLR) is a useful and cost-effective inflammatory marker derived from routine complete blood count. We performed a systematic literature review using the PRISMA statement. Twenty-two articles were included, recruiting 7,601 COPD patients and 784 healthy controls. Compared with controls, COPD patients had significantly higher NLR values. We found a significant correlation between the NLR and clinical/functional parameters (FEV₁, mMRC, and BODE index) in COPD patients. Elevation of the NLR is associated with the diagnosis of acute exacerbation of COPD (pooled data propose a cut-off value of 3.34 with a median sensitivity, specificity, and area under the curve of 80%, 86%, and 0.86, respectively). Additionally, increased NLR is also associated with the diagnosis of a bacterial infection in exacerbated patients, with a cut-off value of 7.30, although with a low sensitivity and specificity. The NLR is an independent predictor of in-hospital and late mortality after exacerbation. In conclusion, the NLR could be a useful marker in COPD patients; however, further studies are needed to better identify the clinical value of the NLR.

Blood and sputum protein biomarkers for chronic obstructive pulmonary disease (COPD)

INTRODUCTION

Chronic obstructive pulmonary disease (COPD) is a heterogeneous set of disorders, characterized by airflow limitation, and reduced lung function. Despite increasing knowledge regarding its pathophysiology, there has been limited advancement in therapeutics and the current treatment strategy is symptom management and prevention of exacerbations. Areas covered: Biomarkers represent important tools for the implementation of precision medicine. As fundamental molecules of all living processes, proteins could provide crucial information about how genes interact with the environment. Proteomics studies could act as important tools in identifying reliable biomarkers to enable a more precise therapeutic approach. In this review, we will explore the most promising blood and sputum protein biomarkers in COPD that have been consistently reported in the literature. Expert commentary: Given the complexity of COPD, no single protein biomarker has been able to improve the outcomes of COPD patients. According to preliminary studies, precision medicine in COPD will likely require a combination of different proteins in a biomarker panel for clinical translation. With advancements in current mass spectrometry techniques, an enhancement in the identification of new biomarkers will be observed, and improvements in sequence database search can fill in potential gaps between biomarker discovery and patient care.

Difference in systemic inflammation and predictors of acute exacerbation between smoking-associated COPD and tuberculosis-associated COPD

Purpose

Tuberculosis-associated COPD (T-COPD) has clinical characteristics similar to those of smoking-associated COPD (S-COPD), such as dyspnea, sputum production, and acute exacerbation (AE). However, the degree of systemic inflammation and prognosis might be different because of difference in the pathophysiology. The aim of this study was to compare the lung function, systemic inflammatory markers, and their impacts on AE in patients with S-COPD and T-COPD.

Patients and methods

We performed a multicenter cross-sectional cohort study. We evaluated clinical characteristics, pulmonary function tests, levels of inflammatory markers, including C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), and IL-6, and the association of these markers with AE in patients with S-COPD and T-COPD.

Results

Patients with T-COPD included more women and had lesser smoking history and higher St George Respiratory Questionnaire score than did patients with S-COPD. Although the FEV₁ of both groups was similar, FVC, vital capacity, total lung capacity, and functional residual capacity were lower in patients with T-COPD than in those with S-COPD. CRP, ESR, and IL-6 levels were significantly higher in patients with T-COPD compared to patients with S-COPD. According to a multivariate logistic regression analysis, FEV₁ was a significant factor predicting AE in S-COPD, and IL-6 was a significant factor predicting AE in T-COPD. IL-6 level greater than 2.04 pg/mL was a cutoff for predicting exacerbation of T-COPD (sensitivity 84.8%, specificity 59.3%, P<0.001).

Conclusion

Patients with T-COPD have higher levels of inflammatory markers, and IL-6 has a predictive value for AE in T-COPD.

Psychological co-morbidities in COPD: Targeting systemic inflammation, a benefit for both?

COPD is a chronic lung disease characterized by persistent respiratory symptoms and airflow limitation due to airway and/or alveolar abnormalities. Furthermore, COPD is often characterized by extrapulmonary manifestations and comorbidities worsening COPD progression and quality of life. A neglected comorbidity in COPD management is mental health impairment defined by anxiety, depression and cognitive problems. This paper summarizes the evidence for impaired mental health in COPD and focuses on current pharmacological intervention strategies. In addition, possible mechanisms in impaired mental health in COPD are discussed with a central role for inflammation. Many comorbidities are associated with multi-organ-associated systemic inflammation in COPD. Considering the accumulative evidence for a major role of systemic inflammation in the development of neurological disorders, it can be hypothesized that COPD-associated systemic inflammation also affects the function of the brain and is an interesting therapeutic target for nutra- and pharmaceuticals.

Integration of Molecular Interactome and Targeted Interaction Analysis to Identify a COPD Disease Network Module

The polygenic nature of complex diseases offers potential opportunities to utilize network-based approaches that leverage the comprehensive set of protein-protein interactions (the human interactome) to identify new genes of interest and relevant biological pathways. However, the incompleteness of the current human interactome prevents it from reaching its full potential to extract network-based knowledge from gene discovery efforts, such as genome-wide association studies, for complex diseases like chronic obstructive pulmonary disease (COPD). Here, we provide a framework that integrates the existing human interactome information with experimental protein-protein interaction data for FAM13A, one of the most highly associated genetic loci to COPD, to find a more comprehensive disease network module. We identified an initial disease network neighborhood by applying a random-walk method. Next, we developed a network-based closeness approach (C_AB) that revealed 9 out of 96 FAM13A interacting partners identified by affinity purification assays were significantly close to the initial network neighborhood. Moreover, compared to a similar method (local radiality), the C_AB approach predicts low-degree genes as potential candidates. The candidates identified by the network-based closeness approach were combined with the initial network neighborhood to build a comprehensive disease network module (163 genes) that was enriched with genes differentially expressed between controls and COPD subjects in alveolar macrophages, lung tissue, sputum, blood, and bronchial brushing datasets. Overall, we demonstrate an approach to find disease-related network components using new laboratory data to overcome incompleteness of the current interactome.

Chronic obstructive pulmonary disease and the development of atrial fibrillation

BACKGROUND

Chronic obstructive pulmonary disease (COPD) has been associated with atrial fibrillation (AF). More insight into the epidemiology and underlying mechanisms is required to optimize management.

METHODS

The Rotterdam Study is a large, population-based cohort study with long-term follow-up. Time dependent Cox proportional hazard models were constructed to study the effect of COPD on incident AF, adjusted for age, sex and pack years of cigarette smoking, and additionally stratified according to exacerbation frequency, left atrial size and baseline systemic inflammatory levels.

RESULTS

1369 of 10,943 subjects had COPD, of whom 804 developed AF. The AF incidence rate was 14 per 1000 person years in COPD and 8 per 1000 person years in subjects without COPD. The adjusted hazard ratio (HR) for COPD subjects to develop AF as compared to subjects without COPD was 1.28 (95%CI [1.04, 1.57]). COPD subjects with frequent exacerbations had a twofold increased AF risk (HR 1.99 [1.42, 2.79]) and COPD subjects with a left atrial size ≥40 mm also had an elevated AF risk (HR 1.77 [1.07, 2.94]). COPD subjects with baseline systemic inflammatory levels above the median had significantly increased AF risks (hsCRP≥1.83 mg/L: HR 1.51 [1.13, 2.03] and IL6 ≥ 1.91 ng/L: HR 2.49 [1.18, 5.28]), whereas COPD subjects below the median had in both analyses no significantly increased AF risk.

CONCLUSIONS

COPD subjects had a 28% increased AF risk, which further increased with frequent exacerbations and an enlarged left atrium. The risk was driven by COPD subjects having elevated systemic inflammatory levels.

Fibrinogen as a potential biomarker for clinical phenotype in patients with chronic obstructive pulmonary disease

Background

Under the Food and Drug Administration's drug development tool qualification program, fibrinogen is the first biomarker drug development tool used in chronic obstructive pulmonary disease (COPD). However, the correlation between fibrinogen and exacerbations among Korean patients with COPD remains unclear.

Methods

In this retrospective cross-sectional study, we included patients with COPD for whom plasma fibrinogen assessment results, without exacerbation, were available. Then, we compared subgroups according to fibrinogen level (threshold: 350 mg/dL). We used multivariate linear regression analysis to investigate the clinical phenotype of COPD with high fibrinogen level, analyzed the correlation between the COPD severity indexes and fibrinogen level.

Results

Of 140 patients, we confirmed 48 (34.3%) patients in the high-level fibrinogen group. The high-level group demonstrated a medical history of more exacerbations than the low-level group. Lung functions [forced expiratory volume in 1 s (FEV₁), forced vital capacity, and 6-minute walk distance] were more deteriorated in the high-level group. Multivariate regression analysis revealed that fibrinogen level was associated with high COPD assessment test score, and experience of exacerbation. Fibrinogen level exhibited a statistically significant positive correlation with COPD severity indexes.

Conclusions

High fibrinogen level seems to reflect frequent exacerbation and severe symptomatic phenotypes in Korean patients with COPD.

Frailty assessment in older adults with chronic obstructive respiratory diseases

The number of patients with chronic obstructive pulmonary disease (COPD) has been rising with continued exposure to environmental risk factors and aging of populations around the world. Frailty is a geriatric syndrome with a decline in physiological reserve and often coexists with chronic diseases such as COPD. Frailty is an independent risk factor for the development and progression of COPD, and COPD can lead to frailty; treating one might improve the other. Thus, there is an increasing interest in the assessment of frailty in patients with COPD. Furthermore, early identification and assessment of frailty in patients with COPD may affect the choice of intervention and improve its effectiveness. Based on the current literature, the intent of this review was to summarize and discuss frailty assessment tools used for COPD patients and the relevant clinical practices for predicting outcomes. We ascertain that using suitable frailty assessment tools could facilitate physicians to screen and stratify physically frail patients with COPD. Screening appropriately targeted population can achieve better intervention outcomes and pulmonary rehabilitation among frail COPD patients.

Indoor black carbon and biomarkers of systemic inflammation and endothelial activation in COPD patients

RATIONALE

Evidence linking traffic-related particle exposure to systemic effects in chronic obstructive lung disease (COPD) patients is limited.

OBJECTIVES

Assess relationships between indoor black carbon (BC), a tracer of traffic-related particles, and plasma biomarkers of systemic inflammation and endothelial activation.

METHODS

BC was measured by reflectance in fine particle samples over a mean of 7.6 days in homes of 85 COPD patients up to 4 times seasonally over a year. After the completion of sampling, plasma C-reactive protein (CRP), interleukin-6 (IL-6), and soluble vascular adhesion molecule-1 (sVCAM-1) were measured. Current smokers and homes with major sources of BC were excluded; therefore, indoor BC was primarily a measure of infiltrated outdoor BC. Mixed effects regression models with a random intercept for each participant were used to assess BC effects at different times (1-9 days before phlebotomy) and in the multi-day sample.

RESULTS

Measured median BC was 0.19 µg/m³ (interquartile range, IQR=0.22 µg/m³). Adjusting for season, race, age, BMI, heart disease, diabetes, ambient temperature, relative humidity, a recent cold or similar illness, and blood draw time, there was a positive relationship between BC and CRP. The largest effect size was for BC averaged over the previous seven days (11.8% increase in CRP per IQR; 95%CI = 1.8-22.9). Effects were greatest among non-statin users and persons with diabetes. There were positive effects of BC on IL-6 only in non-statin users. There were no associations with sVCAM-1.

CONCLUSIONS

These results demonstrate exposure-response relationships between indoor BC with biomarkers of systemic inflammation in COPD patients, with stronger relationships in persons not using statins and with diabetes.

Frailty phenotypes and mortality after lung transplantation: A prospective cohort study

Frailty is associated with increased mortality among lung transplant candidates. We sought to determine the association between frailty, as measured by the Short Physical Performance Battery (SPPB), and mortality after lung transplantation. In a multicenter prospective cohort study of adults who underwent lung transplantation, preoperative frailty was assessed with the SPPB (n = 318) and, in a secondary analysis, the Fried Frailty Phenotype (FFP; n = 299). We tested the association between preoperative frailty and mortality following lung transplantation with propensity score-adjusted Cox models. We calculated postestimation marginalized standardized risks for 1-year mortality by frailty status using multivariate logistic regression. SPPB frailty was associated with an increased risk of both 1- and 4-year mortality (adjusted hazard ratio [aHR]: 7.5; 95% confidence interval [CI]: 1.6-36.0 and aHR 3.8; 95%CI: 1.8-8.0, respectively). Each 1-point worsening in SPPB was associated with a 20% increased risk of death (aHR: 1.20; 95%CI: 1.08-1.33). Frail subjects had an absolute increased risk of death within the first year after transplantation of 12.2% (95%CI: 3.1%-21%). In secondary analyses, FFP frailty was associated with increased risk of death within the first postoperative year (aHR: 3.8; 95%CI: 1.1-13.2) but not over longer follow-up. Preoperative frailty is associated with an increased risk of death after lung transplantation.

Acute Effects of Whole-Body Vibration on Inflammatory Markers in People with Chronic Obstructive Pulmonary Disease: A Pilot Study

Whole-body vibration (WBV) has gained prominence in the rehabilitation of individuals with chronic obstructive pulmonary disease (COPD) because it is a safe and low intensity exercise that promises beneficial effects on physical performance and quality of life. However, its effects on plasma cytokine levels in COPD are still unclear. The aim of the current study was to investigate the acute effects of WBV on inflammatory biomarkers in people with COPD. Twenty-six participants, COPD people (n=13) and healthy controls (n=13), were included. Both groups performed WBV at amplitude of 2 mm and frequency of vibration of 35 Hz, during six series of 30 seconds. They were assessed for lung function, body composition, 6-minute walking test (6MWT), handgrip strength test, plasma concentrations of interleukin (IL), IL-6, IL-8, and IL-10, and soluble tumor necrosis factor alpha (TNF-α) receptors (sTNFR-1 and sTNFR-2). People with COPD had moderate disease [forced expiratory volume in the first second (FEV1) = 58.1%], as well as a worse performance in the 6MWT. The plasma cytokine profile at rest showed that participants with COPD had higher levels of IL-8 and lower levels of IL-10. After one session of WBV, we found an increased plasma IL-10 level in the COPD group, with similar levels for healthy controls. One session of WBV modified the plasma IL-10 level. No effects were found on the other investigated cytokines.

Early Endotyping: A Chance for Intervention in Chronic Obstructive Pulmonary Disease

Chronic obstructive pulmonary disease (COPD) is a syndrome that comprises several lung pathologies, but subphenotyping the various disease subtypes has been difficult. One reason may be that current efforts focused on studying COPD once it has occurred do not allow tracing back to the different origins of disease. This perspective proposes that emphysema originates when susceptible airway, endothelial, and/or hematopoietic cells are exposed to environmental toxins such as cigarette smoke, biomass fuel, or traffic emissions. These susceptible cell types may initiate distinct pathobiological mechanisms ("COPD endotypes") that ultimately manifest the emphysematous destruction of the lung. On the basis of evidence from the "airway" endotype, we suggest that grading these endotypes by severity may allow better diagnosis of disease at early stages when intervention can be designed on the basis of the mechanisms involved. Therefore, genomic, proteomic, and metabolomic studies on at-risk patients will be important in the identification of biomarkers that help designate each endotype. Together with understanding of the involved molecular pathways that lead to disease manifestation, these efforts may lead to development of intervention strategies.

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.

Expansion of a Population of Large Monocytes (Atypical Monocytes) in Peripheral Blood of Patients with Acute Exacerbations of Chronic Obstructive Pulmonary Diseases

Acute exacerbation of chronic obstructive pulmonary disease (AECOPD) is closely associated with airway inflammation including monocytes, lymphocytes, and neutrophils. Monocytes play an essential role in the pathogenesis of chronic obstructive pulmonary disease (COPD). To elucidate the association of circulating monocyte alteration with AECOPD, we analyzed monocyte subpopulation in the peripheral blood of 16 healthy volunteers and 22 AECOPD patients at the stages of admission and remission after clinical therapy. We found a dramatic increase of a previously unreported population of large size circulating atypical monocytes (A Mo) in AECOPD patients, characterized by higher forward scatter and lower side scatter values than the typical monocytes (T Mo) which were observed predominantly in healthy individuals. Further analysis showed that A Mo expressed higher levels of CD16, intercellular adhesion molecule 1 (ICAM-1), and chemotactic protein-1 receptor-2 (CCR2) than T Mo. In contrast, the expression of class II antigen (HLA-DR) by A Mo was lower than T Mo. More importantly, we observed that the percentage of circulating A Mo among total monocytes correlated with the length of hospital stay (time to remission) and disease duration. The data suggest that circulating A Mo might have the potential to serve as a biomarker in the diagnosis and prognosis of AECOPD.

Effects of aging and comorbidities on nutritional status and muscle dysfunction in patients with COPD

Chronic obstructive pulmonary disease (COPD) is a prevalent, complex and debilitating disease which imposes a formidable burden on patients and the healthcare system. The recognition that COPD is a multifaceted disease is not new, and increasing evidence have outlined the importance of its extra-pulmonary manifestations and its relation to other comorbid conditions in the clinical course of the disease and its societal cost. The relationship between aging, COPD and its comorbidities on skeletal muscle function and nutritional status is complex, multidirectional and incompletely understood. Despite this, the current body of knowledge allows the identification of various, seemingly partially independent factors related both to the normal aging process and to the independent deleterious effects of chronic diseases on muscle function and body composition. There is a dire need of studies evaluating the relative contribution of each of these factors, and their potential synergistic effects in patients with COPD and advanced age/comorbid conditions, in order to delineate the best course of therapeutic action in this increasingly prevalent population.

Granulocyte-CSF links destructive inflammation and comorbidities in obstructive lung disease

Chronic obstructive pulmonary disease (COPD) is an incurable inflammatory lung disease that afflicts millions of people worldwide, and it is the fourth leading cause of death. Systemic comorbidities affecting the heart, skeletal muscle, bone, and metabolism are major contributors to morbidity and mortality. Given the surprising finding in large prospective clinical biomarker studies that peripheral white blood cell count is more closely associated with disease than inflammatory biomarkers, we probed the role of blood growth factors. Using the SHIP-1-deficient COPD mouse model, which manifests a syndrome of destructive lung disease and a complex of comorbid pathologies, we have identified a critical and unexpected role for granulocyte-CSF (G-CSF) in linking these conditions. Deletion of G-CSF greatly reduced airway inflammation and lung tissue destruction, and attenuated systemic inflammation, right heart hypertrophy, loss of fat reserves, and bone osteoporosis. In human clinical translational studies, bronchoalveolar lavage fluid of patients with COPD demonstrated elevated G-CSF levels. These studies suggest that G-CSF may play a central and unforeseen pathogenic role in COPD and its complex comorbidities, and identify G-CSF and its regulators as potential therapeutic targets.

Fibrinogen does not relate to cardiovascular or muscle manifestations in COPD: cross-sectional data from the ERICA study

Cardiovascular and skeletal muscle manifestations constitute important comorbidities in COPD, with systemic inflammation proposed as a common mechanistic link. Fibrinogen has prognostic role in COPD. We aimed to determine whether aortic stiffness and quadriceps weakness are linked in COPD, and whether they are associated with the systemic inflammatory mediator-fibrinogen. Aortic pulse wave velocity (aPWV), quadriceps maximal volitional contraction (QMVC) force and fibrinogen were measured in 729 patients with stable, Global Initiative for Chronic Obstructive Lung Disease (GOLD) stages II-IV COPD. The cardiovascular and muscular manifestations exist independently (P=0.22, χ²). Fibrinogen was not associated with aPWV or QMVC (P=0.628 and P=0.621, respectively), making inflammation, as measured by plasma fibrinogen, an unlikely common aetiological factor.

Cigarette smoke exposure promotes differentiation of CD4+ T cells toward Th17 cells by CD40-CD40L costimulatory pathway in mice

Purpose

This study aimed to investigate the impact of cigarette smoke exposure upon CD40–CD40L ligation between bone marrow-derived dendritic cells (BMDCs)and CD4⁺T cells, and to examine the effects of cigarette smoke exposure upon differentiation of CD4⁺T cells toward Th17 cells through blockade of CD40-CD40L pathway in mice.

Methods

The study was processed in vivo and in vitro. In vivo, Th17 cells, CD40, interleukin (IL)-17A, and IL-27 in the lung tissues were quantified and compared between mice with and without cigarette smoke exposure. In vitro, Th17 cells, IL-17A, and IL-27 yielded by multiple cell cultivations in which BMDCs from mice with or without cigarette smoke exposure were fostered with CD4⁺ T cells from healthy mice spleens in the presence of antagonistic CD40 antibody and/or cigarette smoke extract (CSE) were quantified and compared. The flow cytometry was used to detect expressions of Th17 cells and CD40, and the liquid chip was used to detect levels of IL-17A and IL-27.

Results

Both in vivo exposed to cigarette smoke and in vitro to CSE, CD40 expressions noticeably escalated on the surfaces of BMDCs. The presence of Th17 cells, IL-17A, and IL-27 in the lung tissues prominently increased in mice exposed to cigarette smoke. The in vitro culture of CD4⁺ T cells and BMDCs significantly enhanced the differentiation of CD4⁺ T cells toward Th17 cells and secretions of IL-17A and IL-27 in the case that BMDCs were produced from mice exposed to cigarette smoke or the culture occurred in the presence of CSE. Usage of antagonistic CD40 antibody evidently reduced the number of Th17 cells, IL-17A, and IL-27 that increased due to cigarette smoke exposure.

Conclusion

The CD40–CD40L ligation is associated with the quantities of Th17 cells and relevant cytokines in the context of cigarette smoke exposure. Reducing the number of Th17 cells via the usage of antagonistic CD40 antibody can be an inspiration for pursuing a novel therapeutic target for immune inflammation in COPD.

Reduced MBD2 expression enhances airway inflammation in bronchial epithelium in COPD

Background

Chronic obstructive pulmonary disease (COPD) is a common inflammatory lung disease characterized by inflammatory cells activation and production of inflammatory mediators. Methyl-CpG-binding domain protein 2 (MBD2) plays an important role in diverse immunological disorders by regulating immune cell functions, such as differentiation and mediator secretion. However, the role of MBD2 in COPD remains unknown.

Methods

MBD2 protein expression in lung tissues of patients with COPD and cigarette smoke (CS)-exposed mice were evaluated by Western blot and immunohistochemistry. The role of MBD2 in cigarette smoke extract (CSE)-induction of inflammatory mediator expression in the human bronchial epithelial (HBE) cell line was assessed by silencing MBD2 expression in vitro. The involvement of signaling pathways in mediation of inflammation was tested with signaling inhibitors.

Results

Compared with controls, MBD2 expression was distinctly reduced in the bronchial epithelium of both patients with COPD and CS-exposed mice. Moreover, MBD2 expression was decreased in HBE after CSE stimulation in vitro. Moreover, MBD2 knockdown enhanced interleukin (IL)-6 and IL-8 expression in HBE in the presence and absence of CSE treatment by the ERK signaling pathway.

Conclusion

MBD2 protein expression was reduced in the airway epithelium of COPD. In HBE, this reduced expression was associated with increased levels of IL-6 and IL-8 mediated by the ERK pathway. These results suggest that MBD2 could contribute to chronic airway inflammation in COPD.

Mixed Th2 and non-Th2 inflammatory pattern in the asthma-COPD overlap: a network approach

Introduction

The asthma–chronic obstructive pulmonary disease (COPD) overlap (ACO) is a clinical condition that combines features of those two diseases, and that is difficult to define due to the lack of understanding of the underlying mechanisms. Determining systemic mediators may help clarify the nature of inflammation in patients with ACO.

Objectives

We aimed at investigating the role and interaction of common markers of systemic inflammation (IL-6, IL-8, and tumor necrosis factor-α), Th2-related markers (periostin, IL-5, and IL-13), and IL-17 in asthma, COPD, and ACO.

Methods

This is a cross-sectional study of patients aged ≥40 years with a post-bronchodilator forced expiratory volume in the first second/forced vital capacity <0.70 recruited from outpatient clinics in tertiary hospitals with a clinical diagnosis of asthma, COPD, or ACO. ACO was defined by a history of smoking >10 pack-years in a patient with a previous diagnosis of asthma or by the presence of eosinophilia in a patient with a previous diagnosis of COPD. Clinical, functional, and inflammatory parameters were compared between categories using discriminant and network analysis.

Results

In total, 109 ACO, 89 COPD, and 94 asthma patients were included. Serum levels (median [interquartile range]) of IL-5 were higher in asthma patients than in COPD patients (2.09 [0.61–3.57] vs 1.11 [0.12–2.42] pg/mL, respectively; p=0.03), and IL-8 levels (median [interquartile range]) were higher in COPD patients than in asthma patients (9.45 [6.61–13.12] vs 7.03 [4.69–10.44] pg/mL, respectively; p<0.001). Their values in ACO were intermediate between those in asthma and in COPD. Principal component and network analysis showed a mixed inflammatory pattern in ACO in between asthma and COPD. IL-13 was the most connected node in the network, with different weights among the three conditions.

Conclusion

Asthma and COPD are two different inflammatory conditions that may overlap in some patients, leading to a mixed inflammatory pattern. IL-13 could be central to the regulation of inflammation in these conditions.

Emphysema and extrapulmonary tissue loss in COPD: a multi-organ loss of tissue phenotype

We tested whether emphysema progression accompanies enhanced tissue loss in other body compartments in 1817 patients from the ECLIPSE chronic obstructive pulmonary disease (COPD) cohort.Clinical and selected systemic biomarker measurements were compared in subjects grouped by quantitative tomography scan emphysema quartiles using the percentage of low attenuation area (LAA%). Lowest and highest quartile patients had amino-acid metabolomic profiles. We related LAA% to 3 years decline in lung function (forced expiratory volume in 1 s (FEV₁)), body mass index (BMI), fat-free mass index (FFMI) and exacerbations, hospitalisations and mortality rates.Participants with more baseline emphysema had lower FEV₁, BMI and FFMI, worse functional capacity, and less cardiovascular disease but more osteoporosis. Systemic C-reactive protein and interleukin-6 levels were similar among groups, but club cell protein 16 was higher and interleukin-8, surfactant protein D and soluble receptor for advanced glycation end product were lower with more emphysema. Metabolomics differed between extreme emphysema quartiles. Patients with more emphysema had accelerated FEV₁, BMI and FFMI decline and more exacerbations, hospitalisations and mortality.COPD patients with more emphysema undergo excessive loss of pulmonary and extrapulmonary tissue, which is probably related to abnormal tissue maintenance. Because of worse clinical outcomes, we propose this subgroup be named the multi-organ loss of tissue (MOLT) COPD phenotype.

Body weight and mortality in COPD: focus on the obesity paradox

The positive association between overweight, obesity, and cardiovascular and all-cause mortality is well established, even though this relation is typically U shaped with an increased risk also in low-weight subjects. However, being overweight or obese has been associated with a better prognosis in subjects suffering from chronic diseases, id est the "obesity paradox". In both community-dwelling and hospitalized patients with COPD, several studies have reported a significant protective effect of obesity on all-cause mortality, indicating that also in obstructive pulmonary diseases, an obesity paradox may be present. Interestingly, the "paradox" is more evident for subjects with severe bronchial obstruction (i.e., a lower FEV1), while in mild-moderate conditions, the weight-related mortality shows a behavior similar to that observed in the general population. Several factors may confound the relation between COPD, obesity and mortality. The lower FEV1 found in obese people may be linked to a restrictive defect rather than to an obstructive one. Due to the modified chest wall mechanical properties-related to increased fat mass-obese COPD patients may present, respect to their lean counterpart, a lower lung hyperinflation which is associated with higher mortality. The traditional classification of COPD attributes to obese "blue bloaters" a low-grade emphysema in opposition to lean "pink puffers"; the fact that emphysema extent is related to mortality may bias the relationship between weight and survival. It is also to underline that the majority of the studies, consider BMI rather than body composition (a better predictor of mortality) when studying the intriguing relation between weight, COPD, and mortality. Reverse bias has also to be taken into account, hypothesizing that an unintentional weight loss may be the deleterious factor related to mortality, rather than considering obesity a protective one. Further prospective studies are needed to shed light on the complexity of this emerging issue.

LEVEL OF EVIDENCE

Level V: Narrative Review.