Serum biomarkers as predictors of lung function decline in chronic obstructive pulmonary disease

Increased plasma interleukin-1β is associated with accelerated lung function decline in non-smokers

Interleukin-1β is one of the major cytokines involved in the initiation and persistence of airway inflammation in chronic obstructive pulmonary disease (COPD). However, the association between plasma interleukin-1β and lung function decline remains unclear. We aimed to explore the association between plasma interleukin-1β and lung function decline. This longitudinal evaluation of data from the Early COPD study analysed the association between the plasma interleukin-1β concentration, lung function decline, and COPD exacerbation. Overall, 1,328 participants were included in the baseline analysis, and 1,135 (85%) completed the 1-year follow-up. Increased plasma interleukin-1β was associated with accelerated lung function decline in non-smokers (forced expiratory volume in 1 s: per unit natural log-transformed increase, adjusted unstandardised β [95% confidence interval] 101.46 [16.73-186.18] mL/year, p=0.019; forced vital capacity: per unit natural log-transformed increase, adjusted unstandardised β [95% confidence interval] 146.20 [93.65-198.75] mL/year, p<0.001), but not in smokers. In non-smokers, participants with an interleukin-1β concentration in the top 30% (>5.02 pg/mL) had more respiratory symptoms, more severe emphysema and air trapping, and higher levels of inflammation-related biomarkers. In this study, a subgroup with increased plasma interleukin-1β was identified among non-smokers, and increased plasma interleukin-1β was associated with lung function accelerated decline.

Proteomic Risk Score of Increased Respiratory Susceptibility: A Multi-Cohort Study

RATIONALE

Accelerated decline in lung function is associated with incident COPD, hospitalizations and death. However, identifying this trajectory with longitudinal spirometry measurements is challenging in clinical practice.

OBJECTIVE

To determine whether a proteomic risk score trained on accelerated decline in lung function can assess risk of future respiratory disease and mortality.

METHODS

In CARDIA, a population-based cohort starting in young adulthood, longitudinal measurements of FEV1 percent predicted (up to six timepoints over 30 years) were used to identify accelerated and normal decline trajectories. Protein aptamers associated with an accelerated decline trajectory were identified with multivariable logistic regression followed by LASSO regression. The proteomic respiratory susceptibility score was derived based on these circulating proteins and applied to the UK Biobank and COPDGene studies to examine associations with future respiratory morbidity and mortality.

MEASUREMENTS AND RESULTS

Higher susceptibility score was independently associated with all-cause mortality (UKBB: HR 1.56, 95%CI 1.50-1.61; COPDGene: HR 1.75, 95%CI 1.63-1.88), respiratory mortality (UKBB: HR 2.39, 95% CI 2.16-2.64; COPDGene: HR 1.83, 95%CI 1.33-2.51), incident COPD (UKBB: HR 1.84, 95%CI 1.71-1.98), incident respiratory exacerbation (COPDGene: OR 1.11, 95%CI 1.03-1.20), and incident exacerbation requiring hospitalization (COPDGene: OR 1.18, 95%CI 1.08-1.28).

CONCLUSIONS

A proteomic signature of increased respiratory susceptibility identifies people at risk of respiratory death, incident COPD, and respiratory exacerbations. This susceptibility score is comprised of proteins with well-known and novel associations with lung health and holds promise for the early detection of lung disease without requiring years of spirometry measurements.

Systemic Markers of Lung Function and Forced Expiratory Volume in 1 Second Decline across Diverse Cohorts

Rationale: Chronic obstructive pulmonary disease (COPD) is a complex disease characterized by airway obstruction and accelerated lung function decline. Our understanding of systemic protein biomarkers associated with COPD remains incomplete. Objectives: To determine what proteins and pathways are associated with impaired pulmonary function in a diverse population. Methods: We studied 6,722 participants across six cohort studies with both aptamer-based proteomic and spirometry data (4,566 predominantly White participants in a discovery analysis and 2,156 African American cohort participants in a validation). In linear regression models, we examined protein associations with baseline forced expiratory volume in 1 second (FEV1) and FEV1/forced vital capacity (FVC). In linear mixed effects models, we investigated the associations of baseline protein levels with rate of FEV1 decline (ml/yr) in 2,777 participants with up to 7 years of follow-up spirometry. Results: We identified 254 proteins associated with FEV1 in our discovery analyses, with 80 proteins validated in the Jackson Heart Study. Novel validated protein associations include kallistatin serine protease inhibitor, growth differentiation factor 2, and tumor necrosis factor-like weak inducer of apoptosis (discovery β = 0.0561, Q = 4.05 × 10-10; β  = 0.0421, Q = 1.12 × 10-3; and β = 0.0358, Q = 1.67 × 10-3, respectively). In longitudinal analyses within cohorts with follow-up spirometry, we identified 15 proteins associated with FEV1 decline (Q < 0.05), including elafin leukocyte elastase inhibitor and mucin-associated TFF2 (trefoil factor 2; β = -4.3 ml/yr, Q = 0.049; β = -6.1 ml/yr, Q = 0.032, respectively). Pathways and processes highlighted by our study include aberrant extracellular matrix remodeling, enhanced innate immune response, dysregulation of angiogenesis, and coagulation. Conclusions: In this study, we identify and validate novel biomarkers and pathways associated with lung function traits in a racially diverse population. In addition, we identify novel protein markers associated with FEV1 decline. Several protein findings are supported by previously reported genetic signals, highlighting the plausibility of certain biologic pathways. These novel proteins might represent markers for risk stratification, as well as novel molecular targets for treatment of COPD.

Predicting Lung Function Using Biomarkers in Alpha-1 Antitrypsin Deficiency

Lung disease progression in alpha-1 antitrypsin deficiency (AATD) is heterogenous and manifests in different ways. Blood biomarkers are an attractive method of monitoring diseases as they are easy to obtain and repeatable. In non-AATD COPD, blood biomarker panels have predicted disease severity, progression, and mortality. We measured a panel of seven serum biomarkers in 200 AATD patients and compared levels between those with COPD and those without. We assessed whether biomarkers were associated with baseline lung function parameters (FEV1 and TLco) or absolute change in these parameters. In total, 111 patients with a severely deficient genotype of AATD (PiZZ) and COPD were included in the analyses. Pearson's correlation coefficient was measured for biomarker correlations and models were compared using ANOVA. CRP and CCL18 were significantly higher in the serum of AATD COPD versus AATD with no COPD. Biomarkers were not predictive of cross-sectional lung function measurements, however, CC16 was significantly associated with an absolute change in TLco (p = 0.018). An addition of biomarkers to the predictive model for TLco added significant value over covariates alone (R2 0.13 vs. 0.02, p = 0.028). Our findings suggest that CC16 is predictive of emphysema progression in AATD COPD. Proteomics data may reveal alternative candidate biomarkers and further work should include the use of longitudinal biomarker measurements.

TIMP-1 and its potential diagnostic and prognostic value in pulmonary diseases

Tissue inhibitors of metalloproteases (TIMPs) have caught the attention of many scientists due to their role in various physiological and pathological processes. TIMP-1, 2, 3, and 4 are known members of the TIMPs family. TIMPs exert their biological effects by, but are not limited to, inhibiting the activity of metalloproteases (MMPs). The balance between MMPs and TIMPs is critical for maintaining homeostasis of the extracellular matrix (ECM), while the imbalance between MMPs and TIMPs can lead to pathological changes, such as cancer. In this review, we summarized the current knowledge of TIMP-1 in several pulmonary diseases namely, acute lung injury (ALI)/acute respiratory distress syndrome (ARDS), pneumonia, asthma, chronic obstructive pulmonary disease (COPD), cystic fibrosis, and pulmonary fibrosis. Considering the potential of TIMP-1 serving as a non-invasive diagnostic and/or prognostic biomarker, we also reviewed the circulating TIMP-1 levels in translational and clinical studies.

A blood and bronchoalveolar lavage protein signature of rapid FEV1 decline in smoking-associated COPD

Accelerated progression of chronic obstructive pulmonary disease (COPD) is associated with increased risks of hospitalization and death. Prognostic insights into mechanisms and markers of progression could facilitate development of disease-modifying therapies. Although individual biomarkers exhibit some predictive value, performance is modest and their univariate nature limits network-level insights. To overcome these limitations and gain insights into early pathways associated with rapid progression, we measured 1305 peripheral blood and 48 bronchoalveolar lavage proteins in individuals with COPD [n = 45, mean initial forced expiratory volume in one second (FEV1) 75.6 ± 17.4% predicted]. We applied a data-driven analysis pipeline, which enabled identification of protein signatures that predicted individuals at-risk for accelerated lung function decline (FEV1 decline ≥ 70 mL/year) ~ 6 years later, with high accuracy. Progression signatures suggested that early dysregulation in elements of the complement cascade is associated with accelerated decline. Our results propose potential biomarkers and early aberrant signaling mechanisms driving rapid progression in COPD.

The Role of Smoking in the Mechanisms of Development of Chronic Obstructive Pulmonary Disease and Atherosclerosis

Tobacco smoking is a major cause of chronic obstructive pulmonary disease (COPD) and atherosclerotic cardiovascular disease (ASCVD). These diseases share common pathogenesis and significantly influence each other's clinical presentation and prognosis. There is increasing evidence that the mechanisms underlying the comorbidity of COPD and ASCVD are complex and multifactorial. Smoking-induced systemic inflammation, impaired endothelial function and oxidative stress may contribute to the development and progression of both diseases. The components present in tobacco smoke can have adverse effects on various cellular functions, including macrophages and endothelial cells. Smoking may also affect the innate immune system, impair apoptosis, and promote oxidative stress in the respiratory and vascular systems. The purpose of this review is to discuss the importance of smoking in the mechanisms underlying the comorbid course of COPD and ASCVD.

Decreased humoral immune response in the bronchi of rapid decliners with chronic obstructive pulmonary disease

Background

Identification of COPD patients with a rapid decline in FEV1 is of particular interest for prognostic and therapeutic reasons.

Objective

To determine the expression of markers of inflammation in COPD patients with rapid functional decline in comparison to slow or no decliners.

Methods

In COPD patients monitored for at least 3 years (mean ± SD: 5.8 ± 3 years) for lung functional decline, the expression and localization of inflammatory markers was measured in bronchial biopsies of patients with no lung functional decline (FEV1% + 30 ± 43 ml/year, n = 21), slow (FEV1% ml/year, − 40 ± 19, n = 14) and rapid decline (FEV1% ml/year, − 112 ± 53, n = 15) using immunohistochemistry. ELISA test was used for polymeric immunoglobulin receptor (pIgR) quantitation “in vitro”.

Results

The expression of secretory IgA was significantly reduced in bronchial epithelium (p = 0.011) and plasma cell numbers was significantly reduced in the bronchial lamina propria (p = 0.017) of rapid decliners compared to no decliners. Bronchial inflammatory cell infiltration, CD4, CD8, CD68, CD20, NK, neutrophils, eosinophils, mast cells, pIgR, was not changed in epithelium and lamina propria of rapid decliners compared to other groups. Plasma cells/mm² correlated positively with scored total IgA in lamina propria of all patients. “In vitro” stimulation of 16HBE cells with LPS (10 μg/ml) and IL-8 (10 ng/ml) induced a significant increase while H₂O₂ (100 μM) significantly decreased pIgR epithelial expression.

Conclusion

These data show an impaired humoral immune response in rapid decliners with COPD, marked by reduced epithelial secretory IgA and plasma cell numbers in the bronchial lamina propria. These findings may help in the prognostic stratification and treatment of COPD.

Identification of Metabolism-Associated Molecular Subtypes of Chronic Obstructive Pulmonary Disease

Purpose

This study aimed to identify the COPD molecular subtypes reflecting pulmonary function damage on the basis of metabolism-related gene expression, which provided the opportunity to study the metabolic heterogeneity and the association of metabolic pathways with pulmonary function damage.

Methods

Univariate linear regression and the Boruta algorithm were used to select metabolism-related genes associated with forced expiratory volume in the first second (FEV1) and FEV1/forced vital capacity (FVC) in the Evaluation of COPD to Longitudinally Identify Predictive Surrogate Endpoints (ECLIPSE) cohort. COPD subtypes were further identified by consensus clustering with best-fit. Then, we analyzed the differences in the clinical characteristics, metabolic pathways, immune cell characteristics, and transcription features among the subtypes.

Results

This study identified two subtypes (C1 and C2). C1 exhibited higher levels of lower pulmonary function and innate immunity than C2. Ten metabolic pathways were confirmed as key metabolic pathways. The pathways related to N-glycan, hexosamine, purine, alanine, aspartate and glutamate tended to be positively associated with the abundance of adaptive immune cells and negatively associated with the abundance of innate immune cells. In addition, other pathways had opposite trends. All results were verified in Genetic Epidemiology of COPD (COPDGene) datasets.

Conclusion

The two subtypes reflect the pulmonary function damage and help to further understand the metabolic mechanism of pulmonary function in COPD. Further studies are needed to prove the prognostic and therapeutic value of the subtypes.

Bronchial gene expression signature associated with rate of subsequent FEV1 decline in individuals with and at risk of COPD

BACKGROUND

COPD is characterised by progressive lung function decline. Leveraging prior work demonstrating bronchial airway COPD-associated gene expression alterations, we sought to determine if there are alterations associated with differences in the rate of FEV₁ decline.

METHODS

We examined gene expression among ever smokers with and without COPD who at baseline had bronchial brushings profiled by Affymetrix microarrays and had longitudinal lung function measurements (n=134; mean follow-up=6.38±2.48 years). Gene expression profiles associated with the rate of FEV₁ decline were identified by linear modelling.

RESULTS

Expression differences in 171 genes were associated with rate of FEV₁ decline (false discovery rate <0.05). The FEV₁ decline signature was replicated in an independent dataset of bronchial biopsies from patients with COPD (n=46; p=0.018; mean follow-up=6.76±1.32 years). Genes elevated in individuals with more rapid FEV₁ decline are significantly enriched among the genes altered by modulation of XBP1 in two independent datasets (Gene Set Enrichment Analysis (GSEA) p<0.05) and are enriched in mucin-related genes (GSEA p<0.05).

CONCLUSION

We have identified and replicated an airway gene expression signature associated with the rate of FEV₁ decline. Aspects of this signature are related to increased expression of XBP1-regulated genes, a transcription factor involved in the unfolded protein response, and genes related to mucin production. Collectively, these data suggest that molecular processes related to the rate of FEV₁ decline can be detected in airway epithelium, identify a possible indicator of FEV₁ decline and make it possible to detect, in an early phase, ever smokers with and without COPD most at risk of rapid FEV₁ decline.

Thymus and activation-regulated chemokine (TARC/CCL17) predicts decline of pulmonary function in patients with chronic obstructive pulmonary disease

BACKGROUND

The deterioration of pulmonary function, such as FEV₁-decline, is strongly associated with poor prognosis in patients with chronic obstructive pulmonary disease (COPD). However, few investigations shed light on useful biomarkers for predicting the decline of pulmonary function. We evaluated whether thymus and activation-regulated chemokine (TARC), a Th2 inflammation marker, could predict rapid FEV₁-decline in COPD patients.

METHODS

We recruited 161 patients with stable COPD and performed pulmonary function test once every six months. At the time of registration, blood tests, including serum levels of TARC were performed. We assessed the correlation between changes in parameters of pulmonary function tests and serum levels of TARC. The rapid-decline in pulmonary function was determined using 25th percentile of change in FEV₁ or FEV₁ percent predicted (%FEV₁) per year.

RESULTS

In the FEV₁-rapid-decline group, the frequency of exacerbations, the degree of emphysema, and serum levels of TARC was higher than in the non-rapid-decline group. When using %FEV₁ as a classifier instead of FEV₁, age, the frequency of exacerbations, the degree of emphysema and serum levels of TARC in the rapid-decline group was significantly greater than those in the non-rapid-decline group. In univariate logistic regression analysis, TARC was the significant predictive factor for rapid-decline group. In multivariate analysis adjusted for emphysema, serum levels of TARC are independently significant predicting factors for the rapid-decline group.

CONCLUSIONS

TARC is an independent predictive biomarker for the rapid-decline in FEV₁. Measuring serum TARC levels may help the management of COPD patients by predicting the risk of FEV₁ decline.

Airway regulatory T cells are decreased in COPD with a rapid decline in lung function

Background

Differences in the expression of regulatory T cells (Tregs) have been suggested to explain why some smokers develop COPD and some do not. Upregulation of Tregs in response to smoking would restrain airway inflammation and thus the development of COPD; while the absense of such upregulation would over time lead to chronic inflammation and COPD. We hypothesized that—among COPD patients—the same mechanism would affect rate of decline in lung function; specifically, that a decreased expression of Tregs would be associated with a more rapid decline in FEV₁.

Methods

Bronchoscopy with BAL was performed in 52 subjects recruited from the longitudinal OLIN COPD study; 12 with COPD and a rapid decline in lung function (loss of FEV₁ ≥ 60 ml/year), 10 with COPD and a non-rapid decline in lung function (loss of FEV₁ ≤ 30 ml/year), 15 current and ex-smokers and 15 non-smokers with normal lung function. BAL lymphocyte subsets were determined using flow cytometry.

Results

The proportions of Tregs with regulatory function (FoxP3⁺/CD4⁺CD25^bright) were significantly lower in COPD subjects with a rapid decline in lung function compared to those with a non-rapid decline (p = 0.019). This result was confirmed in a mixed model regression analysis in which adjustments for inhaled corticosteroid usage, smoking, sex and age were evaluated. No significant difference was found between COPD subjects and smokers or non-smokers with normal lung function.

Conclusions

COPD subjects with a rapid decline in lung function had lower proportions of T cells with regulatory function in BAL fluid, suggesting that an inability to suppress the inflammatory response following smoking might lead to a more rapid decline in FEV₁.

Trial registration Clinicaltrials.gov identifier NCT02729220

Plasma proteomics and lung function in four community-based cohorts

BACKGROUND

Underlying mechanism leading to impaired lung function are incompletely understood.

OBJECTIVES

To investigate whether protein profiling can provide novel insights into mechanisms leading to impaired lung function.

METHODS

We used four community-based studies (n = 2552) to investigate associations between 79 cardiovascular/inflammatory proteins and forced expiratory volume in 1 s percent predicted (FEV₁%) assessed by spirometry. We divided the cohorts into discovery and replication samples and used risk factor-adjusted linear regression corrected for multiple comparison (false discovery rate of 5%). We performed Mendelian randomization analyses using genetic and spirometry data from the UK Biobank (n = 421,986) to assess causality.

MEASUREMENTS AND MAIN RESULTS

In cross-sectional analysis, 22 proteins were associated with lower FEV₁% in both the discovery and replication sample, regardless of stratification by smoking status. The combined proteomic data cumulatively explained 5% of the variation in FEV₁%. In longitudinal analyses (n = 681), higher plasma levels of growth differentiation factor 15 (GDF-15) and interleukin 6 (IL-6) predicted a more rapid 5-year decline in lung function (change in FEV₁% per standard deviation of protein level -1.4, (95% CI, -2.5 to -0.3) for GDF-15, and -0.8, (95% CI, -1.5 to -0.2) for IL-6. Mendelian randomization analysis in UK-biobank provided support for a causal effect of increased GDF-15 levels and reduced FEV₁%.

CONCLUSIONS

Our combined approach identified GDF-15 as a potential causal factor in the development of impaired lung function in the general population. These findings encourage additional studies evaluating the role of GDF-15 as a causal factor for impaired lung function.

The study of genes and signal transduction pathways involved in mustard lung injury: A gene therapy approach

Sulfur mustard (SM) is a destructive and harmful chemical agent for the eyes, skin and lungs that causes short-term and long-term lesions and was widely used in Iraq war against Iran (1980-1988). SM causes DNA damages, oxidative stress, and Inflammation. Considering the similarities between SM and COPD (Chronic Obstructive Pulmonary Disease) pathogens and limited available treatments, a novel therapeutic approach is not developed. Gene therapy is a novel therapeutic approach that uses genetic engineering science in treatment of most diseases including chronic obstructive pulmonary disease. In this review, attempts to presenting a comprehensive study of mustard lung and introducing the genes therapy involved in chronic obstructive pulmonary disease and emphasizing the pathways and genes involved in the pathology and pathogenesis of sulfur Mustard. It seems that, given the high potential of gene therapy and the fact that this experimental technique is a candidate for the treatment of pulmonary diseases, further study of genes, vectors and gene transfer systems can draw a very positive perspective of gene therapy in near future.

Expressions of MMP-12, TIMP-4, and Neutrophil Elastase in PBMCs and Exhaled Breath Condensate in Patients with COPD and Their Relationships with Disease Severity and Acute Exacerbations

OBJECTIVE

The purpose of this study was to compare matrix metalloproteinase-12 (MMP-12), neutrophil elastase (NE), and tissue inhibitor of metalloproteinase-4 (TIMP-4) in peripheral blood of patients with chronic obstructive pulmonary disease (COPD) and controls. At the same time, MMP-12, NE, and TIMP-4 in exhaled breath condensate (EBC) were also evaluated.

METHODS

Peripheral blood and EBC samples from COPD patients and healthy controls were collected. In serum and EBC, MMP-12, NE, and TIMP-4 proteins were detected by enzyme-linked immunoassays. The mRNA expression levels of MMP-12, NE, and TIMP-4 in peripheral blood mononuclear cells (PBMCs) were analyzed by quantitative real-time polymerase chain reaction (qRT-PCR).

RESULTS

The concentration of TIMP-4 protein in EBC was lower in patients with COPD (P < 0.001). MMP-12 (P = 0.046), NE (P = 0.027), and TIMP-4 (P = 0.005) proteins in serum of patients with COPD showed higher levels of concentration. The mRNA of MMP-12 (P = 0.0067), NE (P = 0.0058), and TIMP-4 (P = 0.0006) in PBMCs of COPD patients showed higher expression levels. Compared with stable patients, mRNA expression level of NE (P = 0.033) in PBMCs of patients with acute exacerbation of COPD was increased. There were differences in the ratio of MMP-12/TIMP-4 in PBMC (P = 0.0055), serum (P = 0.0427), and EBC (P = 0.0035) samples between COPD patients and healthy controls. The mRNA expression of MMP-12 (r = -0.3958, P = 0.0186) and NE (r = -0.3694, P = 0.0290) in COPD patients was negatively correlated with pulmonary function. However, the mRNA expression of TIMP-4 (r = 0.2871, P = 0.0945) in PBMCs was not correlated with the FEV1 of the pulmonary function. Serum MMP-12 level was positively correlated with the MMP-12 level in EBC (P = 0.0387). The level of TIMP-4 in serum was not correlated with the level in the EBC sample (P = 0.4332).

CONCLUSION

The expression levels of MMP-12, NE, and TIMP-4 in PBMCs and serum were elevated in COPD patients. In PBMCs of COPD patients, the mRNA expression level of NE may predict acute exacerbation, and MMP-12 mRNA expression level may be used to reflect the severity of airflow limitation. However, to better assess their diagnostic or prognostic value, larger studies are necessary.

The overexpression of lncRNA H19 as a diagnostic marker for coronary artery disease

OBJECTIVE

Our study aimed to investigate the diagnostic value of lncRNA H19 for coronary artery disease (CAD) and to explore its possible mechanisms.

METHODS

A total of 30 CAD patients and 30 healthy individuals, as well as patients with different cardiovascular diseases, were included in this study. Blood was drawn from each participant to prepare serum samples, and the expression of lncRNA H19 was detected using qRT-PCR. The ROC curve analysis was used to analyze the diagnostic value of H19 for CAD. The effects of patients' basic information and lifestyle on H19 expression were analyzed. The plasma level of TGF-β1 was measured by ELISA. The H19 overexpression in the human primary coronary artery endothelial cell (HCAEC) line was constructed, and the effects of H19 overexpression on the TGF-β1 expression were analyzed using Western blot. The results of H19 expression were specifically upregulated in patients with CAD but not in healthy individuals and patients with other types of cardiovascular diseases. The ROC curve analysis showed that the H19 expression level could be used to predict CAD accurately. Gender, age, and patients' lifestyle had no significant effects on H19 expression, but H19 expression was higher in patients with a longer course of disease in comparison with the controls. H19 expression was positively correlated with the serum level of TGF-β1, and H19 overexpression significantly increased TGF-β1 protein level in HCAEC.

CONCLUSION

H19 overexpression participates in the pathogenesis of CAD by increasing the expression level of TGF-β1, and H19 expression level may serve as a diagnostic marker for CAD.

Environmental exposures and systemic hypertension are risk factors for decline in lung function

BACKGROUND

Chronic lung disease is a leading contributor to the global disease burden; however, beyond tobacco smoke, we do not fully understand what risk factors contribute to lung function decline in low-income and middle-income countries.

METHODS

We collected sociodemographic and clinical data in a randomly selected, age-stratified, sex-stratified and site-stratified population-based sample of 3048 adults aged ≥35 years from four resource-poor settings in Peru. We assessed baseline and annual pre-bronchodilator and post-bronchodilator lung function over 3 years. We used linear mixed-effects models to assess biological, socioeconomic and environmental risk factors associated with accelerated lung function decline.

RESULTS

Mean±SD enrolment age was 55.4±12.5 years, 49.2% were male and mean follow-up time was 2.36 (SD 0.61) years. Mean annual pre-bronchodilator FEV1 decline was 30.3 mL/year (95% CI 28.6 to 32.0) and pre-bronchodilator FVC decline was 32.2 mL/year (30.0 to 34.4). Using multivariable linear mixed-effects regression, we found that urban living, high-altitude dwelling and having hypertension accounted for 25.9% (95% CI 15.7% to 36.1%), 21.3% (11.1% to 31.5%) and 15.7% (3.7% to 26.9%) of the overall mean annual decline in pre-bronchodilator FEV1/height2, respectively. Corresponding estimates for pre-bronchodilator FVC/height2 were 42.1% (95% CI% 29.8% to 54.4%), 36.0% (23.7% to 48.2%) and 15.8% (2.6% to 28.9%) of the overall mean annual decline, respectively.

CONCLUSION

Urbanisation, living at high altitude and hypertension were associated with accelerated lung function decline in a population with low daily smoking prevalence.

Optimization of biomarkers-based classification scores as progression-free survival predictors: an intuitive graphical representation

Aim

To construct classification scores based on a combination of cancer patient plasma biomarker levels, for predicting progression-free survival.

Methods

The approach is based on the optimization of the biomarker cut-off values, which maximize the statistical differences between the groups with values lower or larger than the cut-offs, respectively. An intuitive visualization of the quality of the classification score is also proposed.

Results

Even if there are only weak correlations between individual biomarker levels and progression-free survival, scores based on suitably chosen combination of three biomarkers have classification power comparable with the Response Evaluation Criteria in Solid Tumors criteria classification of response to treatments in solid tumors.

Conclusion

Our approach has the potential to improve the selection of the patients who will benefit from a given anticancer treatment.

Role of the HIF-1 signaling pathway in chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is the most common cause of chronic morbidity and mortality. However, the molecular mechanisms underlying COPD remain largely unknown. The purpose of the present study was to investigate the expression patterns of hypoxia-inducible factor 1α (HIF-1α), vascular endothelial growth factor (VEGF), and VEGF receptor 2 (R2) in regard to the HIF-1 signaling pathway in COPD. The expressions of HIF-1α, VEGF and VEGFR2 were examined and quantified in the human lung tissues of 102 subjects with a defined smoking status, with or without COPD. The expressions of HIF-1α, VEGF and VEGFR2 were observed to be increased in the lung tissues collected from smoking COPD subjects when compared with those tissues from smoking subjects without COPD and non-smoking subjects without COPD. The expression of HIF-1α was shown to be positively associated with the expression of VEGF and VEGFR2. In addition, increased expression of HIF-1α, VEGF and VEGFR2 reflected the disease severity of COPD. The key findings obtained from the present study indicated that high expression of HIF-1α, VEGF and VEGFR2 may be associated with decreased lung function and reduced quality of life, contributing to disease progression in COPD.

Elevated interleukin-6 and bronchiectasis as risk factors for acute exacerbation in patients with tuberculosis-destroyed lung with airflow limitation

Background

Patients with tuberculosis-destroyed lungs (TDLs), with airflow limitation, have clinical characteristics similar to those of patients with chronic obstructive pulmonary disease (COPD). Acute exacerbation is an important factor in the management of TDL. Therefore, the aim of this study was to investigate the factors associated with acute exacerbations in patients with stable TDL with airflow limitation.

Methods

We evaluated the clinical characteristics, such as lung function, image findings, and serum laboratory findings, including C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), and interleukin (IL)-6, in patients with TDL with chronic airflow limitation (n=94). We evaluated the correlation of these parameters with acute exacerbation.

Results

We found that patients with exacerbation were more likely to have bronchiectasis than those without exacerbation (patients with exacerbation, 66.7%; patients without exacerbation, 30.5%; P=0.001). CRP and IL-6 levels were significantly higher in patients with exacerbation than in those without exacerbation (P=0.001 and P<0.001, respectively). Bronchiectasis [OR, 3.248; 95% confidence interval (CI), 1.063-9.928; P=0.039] and elevated IL-6 levels (OR, 1.128; 95% CI, 1.013-1.257; P=0.028) were the most important parameters associated with acute exacerbation in patients with TDL with airflow limitation.

Conclusions

Patients with bronchiectasis and high IL-6 levels may require more intensive treatment to prevent acute exacerbation.

Proteases and Their Inhibitors in Chronic Obstructive Pulmonary Disease

In the context of respiratory disease, chronic obstructive pulmonary disease (COPD) is the leading cause of mortality worldwide. Despite much development in the area of drug development, currently there are no effective medicines available for the treatment of this disease. An imbalance in the protease: Antiprotease ratio in the COPD lung remains an important aspect of COPD pathophysiology and several studies have shown the efficacy of antiprotease therapy in both in vitro and in vivo COPD models. However more in-depth studies will be required to validate the efficacy of lead drug molecules targeting these proteases. This review discusses the current status of protease-directed drugs used for treating COPD and explores the future prospects of utilizing the potential of antiprotease-based therapeutics as a treatment for this disease.

Proteolytic biomarkers are related to prognosis in COPD- report from a population-based cohort

BACKGROUND

The imbalance between proteases and anti-proteases is considered to contribute to the development of COPD. Our aim was to evaluate the protease MMP-9, the antiprotease TIMP-1 and the MMP-9/TIMP-1-ratio as biomarkers in relation to prognosis. Prognosis was assessed as lung function decline and mortality. This was done among subjects with COPD in a population-based cohort.

METHODS

In 2005, clinical examinations including spirometry and peripheral blood sampling, were made in a longitudinal population-based cohort. In total, 1542 individuals participated, whereof 594 with COPD. In 2010, 1031 subjects participated in clinical examinations, and 952 subjects underwent spirometry in both 2005 and 2010. Serum MMP-9 and TIMP-1 concentrations were measured with enzyme linked immunosorbent assay (ELISA). Mortality data were collected from the Swedish national mortality register from the date of examination in 2005 until 31st December 2010.

RESULTS

The correlation between biomarkers and lung function decline was similar in non-COPD and COPD, but only significant for MMP-9 and MMP-9/TIMP-1-ratio in non-COPD. Mortality was higher in COPD than non-COPD (16% vs. 10%, p = 0.008). MMP-9 concentrations and MMP-9/TIMP-1 ratios in 2005 were higher among those who died during follow up, as well as among those alive but not participating in 2010, when compared to those participating in the 2010-examination. In non-COPD, male sex, age, burden of smoking, heart disease and MMP-9/TIMP-1 ratio were associated with increased risk for death, while increased TIMP-1 was protective. Among those with COPD, age, current smoking, increased MMP-9 and MMP-9/TIMP-1 ratio were associated with an increased risk for death.

CONCLUSIONS

The expected association between these biomarkers and lung function decline in COPD was not confirmed in this population-based study, probably due to a healthy survivor effect. Still, it is suggested that increased proteolytic imbalance may be of greater prognostic importance in COPD than in non-COPD.

The systemic nature of mustard lung: Comparison with COPD patients

Sulphur mustard (SM) is a powerful blister-causing alkylating chemical warfare agent used by Iraqi forces against Iran. One of the known complications of mustard gas inhalation is mustard lung which is discussed as a phenotype of chronic obstructive pulmonary disease (COPD). In this complication, there are clinical symptoms close to COPD with common etiologies, such as in smokers. Based on information gradually obtained by conducting the studies on mustard lung patients, systemic symptoms along with pulmonary disorders have attracted the attention of researchers. Changes in serum levels of inflammatory markers, such as C-reactive protein (CRP), tumor necrosis factor alpha (TNF-α), nuclear factor κB (NF-κB), matrix metalloproteinases (MMPs), interleukin (IL), chemokines, selectins, immunoglobulins, and signs of imbalance in oxidant-antioxidant system at serum level, present the systemic changes in these patients. In addition to these, reports of extra-pulmonary complications, such as osteoporosis and cardiovascular disease are also presented. In this study, the chance of developing the systemic nature of this lung disease have been followed on using the comparative study of changes in the mentioned markers in mustard lung and COPD patients at stable phases and the mechanisms of pathogenesis and phenomena, such as airway remodeling in these patients.

Relationship of serum levels of interleukin 6, interleukin 8, and C-reactive protein with forced expiratory volume in first second in patients with mustard lung and chronic obstructive pulmonary diseases: systematic review and meta-analysis

INTRODUCTION

The chronic systemic inflammation is a result of releasing inflammatory cytokines from the cells relating to the body immunity system and chronic activation of the innate immunity system.

AIM

To evaluate the relationship among serum levels of interleukin 6 (IL-6), interleukin 8 (IL-8), C-reactive protein (CRP) with forced expiratory volume in 1st s (FEV1) in patients with mustard lung (ML) and chronic obstructive pulmonary diseases (COPD).

MATERIAL AND METHODS

A published literature search was performed through SID, web of science, ISI, Science Direct, Scopus, Medline, and PubMed databases for articles published in English. The correlation coefficient (r) and 95% confidence intervals (95% CIs) were calculated using random or fixed effects models. Heterogeneity was assessed using χ2 and I2 statistics.

RESULTS

In total, 4 published studies were included in the final analysis. Using the random-effect model, meta-analysis showed that the r was -0.052 (95% CI: -0.14-0.049, p = 0.28) at serum level of IL-8, serum levels of CRP and FEV1 in these results were r = -0.13, p = 0.012, serum levels of tumor necrosis factor (TNF) and FEV1 levels were r = -0.39, p = 0.03 in the conducted studies on mustard lung patients. The IL-6 serum level was explored in COPD patients. The results of the given studies in these patients are r = -0.006, 95% CI: -0.37-0.15, and p = 0.44.

CONCLUSIONS

In this meta-analysis, there was evidence that serum levels of CRP and TNF have been significantly increased in chronic obstructive pulmonary diseases compared to the healthy control group, which signifies the presence of systemic inflammation in ML and COPD patients.

Is periodontitis a comorbidity of COPD or can associations be explained by shared risk factors/behaviors?

COPD is recognized as having a series of comorbidities potentially related to common inflammatory processes. Periodontitis is one of the most common human inflammatory diseases and has previously been associated with COPD in numerous observational studies. As periodontitis and COPD are both chronic, progressive conditions characterized by neutrophilic inflammation with subsequent proteolytic destruction of connective tissue, it has been proposed that they share common pathophysiological processes. The mechanisms proposed to link COPD and periodontitis include mechanical aspiration of oral contents into the respiratory tree, overspill of locally produced inflammatory mediators into the systemic circulation or oral or lung-derived bacteremia activating an acute-phase response and also reactive oxygen species (ROS) and cytokine release by systemic neutrophils at distant sites. Studies of systemic neutrophils in COPD and chronic periodontitis describe altered cellular functions that would predispose to inflammation and tissue destruction both in the lung and in the mouth, again potentially connecting these conditions. However, COPD and periodontitis also share risk factors such as age, chronic tobacco smoke exposure, and social deprivation that are not always considered in observational and interventional studies. Furthermore, studies reporting associations have often utilized differing definitions of both COPD and periodontitis. This article reviews the current available evidence supporting the hypothesis that COPD and inflammatory periodontal disease (periodontitis) could be pathologically associated, including a review of shared inflammatory mechanisms. It highlights the potential limitations of previous studies, in particular, the lack of uniformly applied case definitions for both COPD and periodontitis and poor recognition of shared risk factors. Understanding associations between these conditions may inform why patients with COPD suffer such a burden of comorbid illness and new therapeutic strategies for both the diseases. However, further research is needed to clarify factors that may be directly causal as opposed to confounding relationships.

End-of-life prognostic indicators in patients with COPD: Part 1

In the UK, chronic respiratory diseases cause 13% of adult disability. The major chronic respiratory disease is chronic obstructive pulmonary disease (COPD), a condition involving chronic airway inflammation that causes airflow obstruction and destruction of lung tissue. This leads to a progressive loss of respiratory membrane, which accounts for the clinical manifestation of COPD, which is difficulty maintaining sufficient gas exchange to meet metabolic demands. The primary cause is smoking, with the vast majority of COPD patients having a past or present history of smoking. However exposure to industrial pollutants is also a contributing factor, as is a rare genetic predisposition to developing COPD.

Concomitant elevations of MMP-9, NGAL, proMMP-9/NGAL and neutrophil elastase in serum of smokers with chronic obstructive pulmonary disease

A growing body of evidence points towards smoking‐related phenotypic differences in chronic obstructive pulmonary disease (COPD). As COPD is associated with systemic inflammation, we determined whether smoking status is related to serum levels of matrix metalloproteinase‐9 (pro‐ and active MMP‐9), neutrophil gelatinase‐associated lipocalin (NGAL) and the proMMP‐9/NGAL complex in patients with COPD. Serum samples were collected in 100 stable‐phase COPD patients (82 smokers, 18 never‐smokers) and 28 healthy adults (21 smokers, 7 never‐smokers). Serum levels of studied factors were measured in ELISA. Our data provide the first evidence of simultaneously elevated serum levels of MMP‐9, NGAL and proMMP‐9/NGAL in COPD smokers. While the triad discriminated between smokers and non‐smokers in the COPD group, MMP‐9 and proMMP‐9/NGAL (but not NGAL) discriminated between smokers with and without COPD. Adjustment for age and smoking pack‐years did not alter the findings. Serum MMP‐9, NGAL and proMMP‐9/NGAL levels were not correlated with the GOLD stage or FEV1 decline. Furthermore, serum levels of neutrophil elastase (NE) and MMP‐3 (but not of IL‐6 and MMP‐12) were also higher in COPD smokers than in healthy smokers before and after adjustment for age and pack‐years. Among COPD smokers, levels of MMP‐9, NGAL and proMMP‐9/NGAL were positively correlated with NE (P < 0.0001) but not with the remaining factors. Gelatin zymography detected proMMP‐9 in serum samples of healthy and COPD smoking groups. Our results suggest that associated serum levels of proMMP‐9, NGAL, proMMP‐9/NGAL and NE may reflect the state of systemic inflammation in COPD related to cigarette smoking.

MMP-8, MMP-9 and Neutrophil Elastase in Peripheral Blood and Exhaled Breath Condensate in COPD

Chronic obstructive pulmonary disease (COPD) is characterised by progressive and irreversible airflow limitation associated with chronic inflammation involving cytokines and metalloproteinases (MMPs). MMP-8, MMP-9 and neutrophil elastase (NE) are known to be implicated in COPD but the factors influencing activation and suppression remain unclear. This study aimed to compare MMP-8, MMP-9 and NE in the peripheral blood of COPD patients and controls and to likewise assess exhaled breath condensate (EBC) for these MMPs. Peripheral blood micro(mi)RNA139-5p levels, which may regulate MMPs in COPD, were also measured. Blood and EBC were collected from COPD patients (stable and during exacerbations) and healthy controls. Expression of mRNA for MMP-8, MMP-9, NE and miRNA-139-5p expression in peripheral blood mononuclear cells (PBMCs) was measured using qRT-PCR. MMP-8, MMP-9 and NE protein in plasma as well as MMP-8 and MMP-9 protein in EBC were analysed by enzyme-linked immunoassays. PBMCs from COPD patients showed greater expression of mRNA for MMP-8 (p = 0.0004), MMP-9 (p = 0.0023) and NE (p = 0.0019). PBMC expression of mRNA for NE was significantly higher in COPD exacerbations compared to stable cases (p < 0.05). Expression of mRNA for MMP-9 and NE correlated negatively with spirometry in patients (p < 0.05). Plasma from COPD patients showed greater levels of protein for MMP-8 (p = 0.003), MMP-9 (p = 0.046) and NE (p = 0.018). MMP-8 protein levels were lower in the EBC of COPD patients (p < 0.0001). In PBMCs, enhanced expression of mRNA for MMP-9 and NE is associated with COPD and may correlate with disease severity and exacerbations.

Multiple Circulating Cytokines Are Coelevated in Chronic Obstructive Pulmonary Disease

Inflammatory biomarkers, including cytokines, are associated with COPD, but the association of particular circulating cytokines with systemic pathology remains equivocal. To investigate this, we developed a protein microarray system to detect multiple cytokines in small volumes of serum. Fourteen cytokines were measured in serum from never-smokers, ex-smokers, current smokers, and COPD patients (GOLD stages 1–3). Certain individual circulating cytokines (particularly TNFα and IL-1β) were significantly elevated in concentration in the serum of particular COPD patients (and some current/ex-smokers without COPD) and may serve as markers of particularly significant systemic inflammation. However, numerous circulating cytokines were raised such that their combined, but not individual, elevation was significantly associated with severity of disease, and these may be further indicators of, and contributors to, the systemic inflammatory manifestations of COPD. The coelevation of numerous circulating cytokines in COPD is consistent with the insidious development, chronic nature, and systemic comorbidities of the disease.

Relationship between plasma matrix metalloproteinase levels, pulmonary function, bronchodilator response, and emphysema severity

Objective

Chronic obstructive pulmonary disease (COPD) is characterized by chronic inflammation in the airway and lung. A protease–antiprotease imbalance has been suggested as a possible pathogenic mechanism for COPD. We evaluated the relationship between matrix metalloproteinase (MMP) levels and COPD severity.

Methods

Plasma levels of MMP-1, MMP-8, MMP-9, and MMP-12 were measured in 57 COPD patients and 36 normal controls. The relationship between MMP levels and lung function, emphysema index, bronchial wall thickness, pulmonary artery pressure, and quality of life was examined using general linear regression analyses.

Results

There were significant associations of MMP-1 with bronchodilator reversibility and of MMP-8 and MMP-9 with lung function. Also, MMP-1, MMP-8, and MMP-9 levels were correlated with the emphysema index, independent of lung function. However, MMP-12 was not associated with lung function or emphysema severity. Associations between MMP levels and bronchial wall thickness, pulmonary artery pressure, and quality of life were not statistically significant.

Conclusion

Plasma levels of MMP-1, MMP-8, and MMP-9 are associated with COPD severity and can be used as a biomarker to better understand the characteristics of COPD patients.

Sputum neutrophils are elevated in smelter workers, and systemic neutrophils are associated with rapid decline in FEV1

OBJECTIVES

In a previous study on smelter workers we, found significant relationship between exposure to dust and accelerated annual decline in forced expiratory volume in 1 s (FEV1). In this cross-sectional study at the end of a follow-up, we aimed to investigate the possible association between annual decline in FEV1 and markers of airways, and systemic inflammation in smelter workers.

METHODS

Employees (n=76 (27 current smokers)) who had been part of a longitudinal study (9-13 years) that included spirometry (>6 measurements) and respiratory questionnaires, performed induced sputum, exhaled NO and had blood drawn. Participants with annual decline in FEV1≥45 mL were compared with participants with annual decline <45 mL; also 26 non-exposed controls were included.

RESULTS

Compared with non-exposed controls, smelter workers demonstrated a significantly increased percentage of neutrophils (mean (SD)) (57% (17) vs 31% (15)) and matrix metalloproteinases 8 (MMP-8) levels in sputum, and MMP-9, surfactant protein D (SpD) and transforming growth factor β (TGFb) levels in blood. A significant association in FEV1≥45 mL was found for blood neutrophils when controlling for smoking habits (OR=1.7 (95% CI 1.0 to 2.8), p=0.045). Airway and blood protein markers were not associated with annual decline in FEV1.

CONCLUSIONS

All workers displayed airway and systemic inflammation characterised by increased levels of neutrophils and MMP-8 in sputum, and MMP-9, SpD and TGFβ in blood compared with non-exposed controls. Blood neutrophils in particular were significantly elevated in those workers with the most rapid decline in lung function. A similar observation was not seen with airway neutrophils. In the present study, we were able to identify systemic but not airway inflammatory markers that can predict increased decline in FEV1 in smelter workers.

Free Urinary Desmosine and Isodesmosine as COPD Biomarkers: The Relevance of Confounding Factors

Background: Desmosine (DES) and isodesmosine (IDES) have been widely discussed as potential biomarkers of COPD. However, their clinical utility and validity remains unproven. Aim: This study aims to progress DES/IDES evaluation as a chronic obstructive pulmonary disease (COPD) biomarker by investigating its urinary excretion in a large sample cohort with respect to a) which factors influence DES/IDES levels in a population of healthy control individuals and COPD individuals; b) whether DES/IDES levels enable the differentiation between COPD individuals and healthy control individuals; c) whether DES/IDES can be used to differentiate between fast and slow decliners in lung function. Methods: Urinary DES and IDES were quantified in 365 individuals (147 healthy control individuals and 218 COPD individuals) from the Evaluation of COPD Longitudinally to Indentify Predictive Surrogate Endpoints (ECLIPSE) study (NCT00292552) by employing a validated liquid chromatography tandem mass spectrometry (LC-MS/MS) method. Results: Age, gender, body mass index (BMI) and smoking have a significant (p<0.05) influence on DES/IDES urinary excretion and need to be corrected for when investigating DES/IDES as a disease biomarker. Urinary DES/IDES allowed a statistically relevant differentiation (p<0.05) between stable COPD individuals and healthy control individuals, however, assay sensitivity and specificity were low (62% and 73%, respectively). Furthermore, urinary DES/IDES does not allow the differentiation of fast and slow decliners in lung function. Conclusions: The present results suggest that while urinary DES/IDES excretion is related to COPD, it is not a sensitive or specific biomarker for COPD diagnosis or prognosis.

Associations of pulmonary function with serum biomarkers and dialysis adequacy in patients undergoing peritoneal dialysis

BACKGROUND

As lung impairment is an indicator of increased morbidity and mortality in patients receiving continuous ambulatory peritoneal dialysis (CAPD), the risk factors associated with impaired lung function are of great significance. The aim of this study is to elucidate the effects of inflammatory biomarkers and dialysis adequacy on pulmonary function, in CAPD patients.

METHODS

101 patients undergoing CAPD, 30 CKD5 patients and 30 healthy subjects were enrolled. Spirometry and serum biomarkers were evaluated in each subject. Pulmonary function was compared among patients and control groups. Pearson analysis was used to analyze the correlation between serum biomarkers, dialysis adequacy and pulmonary function.

RESULTS

Lower vital capacity, maximal voluntary ventilation (MVV), forced vital capacity (FVC), peak expiratory flow (PEF), maximal mid-expiratory flow rate (MMEF), and diffusing capacity of the lung for carbon monoxide (DLCO) were observed in the CAPD group (all P < 0.05) when compared with control subjects. DLCO % was negatively correlated with CRP (r = -0.349, P = 0.007) and positively correlated with albumin (r = 0.401, P = 0.002). Total Kt/V was associated positively with MMEF % (r = 0.316, P = 0.019), and MVV % (r = 0.362, P = 0.007). nPNA was positively correlated with FVC % (r = 0.295, P = 0.049) and MMEF % (r = 0.381, P = 0.010).

CONCLUSION

The results suggest that lung function decline was directly related to higher CRP level, hypoalbuminemia, and dialysis inadequacy. These findings provide the evidence that inflammation and dialysis adequacy play a role in predicting outcomes of CAPD patients with pulmonary impairment.

Implications of the inflammatory response for the identification of biomarkers of chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is characterized by both local and systemic inflammation. Because inflammation plays a critical role in the development, course and severity of COPD, inflammatory markers have the potential to improve the current diagnostic and prognostic approaches. Local inflammation in COPD is characterized by an infiltration of inflammatory cells, with an increased expression of cytokines, chemokines, enzymes, growth factors and adhesion molecules. Systemic low-grade inflammation is another common but nonspecific finding in COPD. Exacerbations of COPD are acute clinical events accompanied by an exaggerated inflammatory response. Future investigations in the field of COPD biomarkers should take into account different study designs and biochemical assays, disease course and duration, variations in symptom severity and timing of measurement.

Serum Metabolite Biomarkers Discriminate Healthy Smokers from COPD Smokers

COPD (chronic obstructive pulmonary disease) is defined by a fixed expiratory airflow obstruction associated with disordered airways and alveolar destruction. COPD is caused by cigarette smoking and is the third greatest cause of mortality in the US. Forced expiratory volume in 1 second (FEV1) is the only validated clinical marker of COPD, but it correlates poorly with clinical features and is not sensitive enough to predict the early onset of disease. Using LC/MS global untargeted metabolite profiling of serum samples from a well-defined cohort of healthy smokers (n = 37), COPD smokers (n = 41) and non-smokers (n = 37), we sought to discover serum metabolic markers with known and/or unknown molecular identities that are associated with early-onset COPD. A total of 1,181 distinct molecular ions were detected in 95% of sera from all study subjects and 23 were found to be differentially-expressed in COPD-smokers vs. healthy-smokers. These 23 putative biomarkers were differentially-correlated with lung function parameters and used to generate a COPD prediction model possessing 87.8% sensitivity and 86.5% specificity. In an independent validation set, this model correctly predicted COPD in 8/10 individuals. These serum biomarkers included myoinositol, glycerophopshoinositol, fumarate, cysteinesulfonic acid, a modified version of fibrinogen peptide B (mFBP), and three doubly-charged peptides with undefined sequence that significantly and positively correlate with mFBP levels. Together, elevated levels of serum mFBP and additional disease-associated biomarkers point to a role for chronic inflammation, thrombosis, and oxidative stress in remodeling of the COPD airways. Serum metabolite biomarkers offer a promising and accessible window for recognition of early-stage COPD.

Increased serum TRAIL and DR5 levels correlated with lung function and inflammation in stable COPD patients

Background

Chronic obstructive pulmonary disease (COPD) is associated with abnormal systemic inflammation, and apoptosis is one of the pathogenic mechanisms of COPD. Several studies have suggested that tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) and its receptors were not only involved in diseases associated with apoptosis but also in inflammatory diseases. However, limited data about the possible relationship between COPD and TRAIL/TRAIL-receptors are available.

Objective

To evaluate the potential relationship between TRAIL/TRAIL-receptors and COPD.

Methods

Serum levels of TRAIL, decoy receptor 5 (DR5), C-reactive protein, and tumor necrosis factor-α were analyzed using multiplex enzyme-linked immunosorbent assay kits. Then, serum levels of TRAIL and DR5 in 57 COPD patients with 35 healthy controls were compared and correlated with lung function and systemic inflammation.

Results

Mean levels of serum TRAIL and DR5 were significantly higher in COPD patients than those in controls (50.17±17.70 versus 42.09±15.49 pg/mL, P=0.029; 48.15±22.88 versus 38.94±10.95 pg/mL, P=0.032, respectively). Serum levels of TRAIL and DR5 correlated inversely with forced expiratory volume in 1 second % predicted, an index of lung function in COPD (r=-0.354, P=0.007 for TRAIL; r=−0.394, P=0.002 for DR5) in all participants (r=-0.291, P=0.005 for TRAIL; r=−0.315, P=0.002 for DR5), while DR5 correlated positively with C-reactive protein (r=0.240, P=0.021 for total subjects) and TRAIL correlated positively with tumor necrosis factor-α (r=0.371, P=0.005 for COPD; r=0.349, P=0.001 for total subjects).

Conclusion

Our results suggested that circulating TRAIL and DR5 increased in COPD patients and were associated with lung function and systemic inflammation in COPD. Future studies are needed to verify whether and how TRAIL and its receptors play roles in COPD.

Matrix metalloproteinases -8 and -9 in the Airways, Blood and Urine During Exacerbations of COPD

Matrix metalloproteinases (MMPs) are elevated in the airways and blood of COPD patients, contributing to disease pathogenesis and tissue remodelling. However, it is not clear if MMP levels in airways, blood and urine are related or if MMP levels are related to disease severity or presence of exacerbations requiring hospitalisation. Seventy-two patients requiring hospitalisation for COPD exacerbations had serum, urine and sputum MMP-8, -9 and active MMP-9 measured by ELISA and gelatin zymography on day one, five and four weeks later (recovery). Clinical history, spirometry, COPD Assessment Test and MRC dyspnoea score were obtained. Twenty-two stable COPD patients had MMP measurements one week apart. During exacerbations, serum and urine MMP-9 were slightly elevated by 17% and 30% compared with recovery values respectively (p = 0.001 and p = 0.026). MMP-8 was not significantly changed. These MMP levels related to serum neutrophil numbers but not to outcome of exacerbations, disease severity measures or smoking status. In clinically stable patients, serum MMP levels did not vary significantly over 7 days, whereas urine MMPs varied by up to nine fold for MMP-8 (p = 0.003). Sputum, serum and urine contained different MMP species and complexes. Median values for sputum active MMP-9 were significantly different from serum (p = 0.035) and urine (p = 0.024). Serum and urine MMPs are only modestly elevated during exacerbations of COPD and unlikely to be useful biomarkers in this clinical setting. Airway, serum and urine MMP levels are independent of each other in COPD patients. Further, MMP levels are variable between patients and do not reflect airflow obstruction.

Adipokine CTRP-5 as a Potential Novel Inflammatory Biomarker in Chronic Obstructive Pulmonary Disease

Local and systemic inflammation often present in chronic obstructive pulmonary disease (COPD). Adipokines are secretory protein mediators by adipose tissue, which have been found to involve in inflammatory responses in many chronic inflammatory diseases. Therefore, we performed this preliminary clinical study to investigate the possible association between 2 adipokines, C1q/tumor necrosis factor-related protein-3 and -5 (CTRP-3 and CTRP-5), with lung function and other markers of inflammation in COPD. Serum CTRP-3 and CTRP-5 levels were measured in 73 COPD patients and 54 health controls, together with lung function and levels of adiponectin, CRP, TNF-α, and MPO in both groups. Pearson's partial correlation was used to analyze the correlations between CTRPs and other serum markers or lung function. Serum CTRP-5 was significantly elevated in COPD patients (0.41 ± 0.35 versus 0.29 ± 0.28 μg/ml, P = 0.01) and correlated inversely with FEV1/FVC ratio in all patients (r = -0.31, P = 0.001). In COPD patients, CTRP-5 was also correlated negatively with FEV1% predicted (r = -0.464, P < 0.001) and had a positive association with CRP levels (r = 0.262, P = 0.04). However, serum CTRP-3 levels were not correlated with measures of lung function or systemic inflammation. In conclusion, circulating CTRP-5 was associated with the severity of airflow obstruction and systemic inflammation in patients with COPD, which suggests that it may be used as a potential novel inflammatory biomarker in COPD. Further studies should be performed to clarify the exact role of CTRP-5 on the pathogenesis and outcomes of COPD.

Serum metalloproteinase-9 is related to COPD severity and symptoms - cross-sectional data from a population based cohort-study

BACKGROUND

Chronic obstructive pulmonary disease, COPD, is an increasing cause of morbidity and mortality worldwide, and an imbalance between proteases and antiproteases has been implicated to play a role in COPD pathogenesis. Matrix metalloproteinases (MMP) are important proteases that along with their inhibitors, tissue inhibitors of metalloproteinases (TIMP), affect homeostasis of elastin and collagen, of importance for the structural integrity of human airways. Small observational studies indicate that these biomarkers are involved in the pathogenesis of COPD. The aim of this study was to investigate serum levels of MMP-9 and TIMP-1 in a large Swedish population-based cohort, and their association with disease severity and important clinical symptoms of COPD such as productive cough.

METHODS

Spirometry was performed and peripheral blood samples were collected in a populations-based cohort (median age 67 years) comprising subjects with COPD (n = 594) and without COPD (n = 948), in total 1542 individuals. Serum MMP-9 and TIMP-1 concentrations were measured with enzyme linked immunosorbant assay (ELISA) and related to lung function data and symptoms.

RESULTS

Median serum MMP-9 values were significantly higher in COPD compared with non-COPD 535 vs. 505 ng/ml (P = 0.017), without any significant differences in serum TIMP-1-levels or MMP-9/TIMP-1-ratio. In univariate analysis, productive cough and decreasing FEV1% predicted correlated significantly with increased MMP-9 among subjects with COPD (P = 0.004 and P = 0.001 respectively), and FEV1% predicted remained significantly associated to MMP-9 in a multivariate model adjusting for age, sex, pack years and productive cough (P = 0.033).

CONCLUSION

Productive cough and decreasing FEV1 were each associated with MMP-9 in COPD, and decreasing FEV1 remained significantly associated with MMP-9 also after adjustment for common confounders in this population-based COPD cohort. The increased serum MMP-9 concentrations in COPD indicate an enhanced proteolytic activity that is related to disease severity, and further longitudinal studies are important for the understanding of MMP-9 in relation to the disease process and the pathogenesis of different COPD phenotypes.

Therapy with plasma purified alpha1-antitrypsin (Prolastin®) induces time-dependent changes in plasma levels of MMP-9 and MPO

The common Z mutation (Glu342Lys) of α1-antitrypsin (A1AT) results in the polymerization and intracellular retention of A1AT protein. The concomitant deficiency of functional A1AT predisposes PiZZ subjects to early onset emphysema. Clinical studies have implied that, among the biomarkers associated with emphysema, matrix metalloproteinase 9 (MMP-9) is of particular importance. Increased plasma MMP-9 levels are proposed to predict the decline of lung function as well as greater COPD exacerbations in A1AT deficiency-associated emphysema. The aim of the present study was to investigate the effect of A1AT therapy (Prolastin) on plasma MMP-9 and myeloperoxidase (MPO) levels. In total 34 PiZZ emphysema patients were recruited: 12 patients without and 22 with weekly intravenous (60 mg/kg body weight) A1AT therapy. The quantitative analysis of A1AT, MMP-9 and MPO was performed in serum and in supernatants of blood neutrophils isolated from patients before and after therapy. Patients with Prolastin therapy showed significantly lower serum MMP-9 and MPO levels than those without therapy. However, parallel analysis revealed that a rapid infusion of Prolastin is accompanied by a transient elevation of plasma MMP-9 and MPO levels. Experiments with freshly isolated blood neutrophils confirmed that therapy with Prolastin causes transient MMP-9 and MPO release. Prolastin induced the rapid release of MMP-9 and MPO when added directly to neutrophil cultures and this reaction was associated with the presence of IgA in A1AT preparation. Our data support the conclusion that changes in plasma levels of MMP-9 and MPO mirror the effect of Prolastin on blood neutrophils.

Surfactant protein D, Club cell protein 16, Pulmonary and activation-regulated chemokine, C-reactive protein, and Fibrinogen biomarker variation in chronic obstructive lung disease

Chronic obstructive pulmonary disease (COPD) is a multifaceted condition that cannot be fully described by the severity of airway obstruction. The limitations of spirometry and clinical history have prompted researchers to investigate a multitude of surrogate biomarkers of disease for the assessment of patients, prediction of risk, and guidance of treatment. The aim of this review is to provide a comprehensive summary of observations for a selection of recently investigated pulmonary inflammatory biomarkers (Surfactant protein D (SP-D), Club cell protein 16 (CC-16), and Pulmonary and activation-regulated chemokine (PARC/CCL-18)) and systemic inflammatory biomarkers (C-reactive protein (CRP) and fibrinogen) with COPD. The relevance of these biomarkers for COPD is discussed in terms of their biological plausibility, their independent association to disease and hard clinical outcomes, their modification by interventions, and whether changes in clinical outcomes are reflected by changes in the biomarker.

Presence of Renal Simple Cysts Is Associated With Increased Risk of Abdominal Aortic Aneurysms

We compared the incidence of renal simple cysts in 271 patients with abdominal aortic aneurysm (AAA) and 1387 patients without AAA (controls) using computed tomography (CT) angiography and abdominal CT, as a health screening program. The AAA group had significantly higher prevalence of renal simple cysts (55% vs 19%, P = .001) and chronic obstructive pulmonary disease (COPD; 12% vs 1%, P = .011) than the controls. After propensity score matching (n = 164), the prevalence of renal simple cysts was still significantly higher in the AAA group. In multivariate analysis, independent predictors of AAA were age, male gender, smoking history, hypertension, high-sensitivity C-reactive protein, creatinine, COPD, and renal simple cysts. The structural weakness predisposing for renal simple cysts may be associated with the initiation of AAA formation. More studies are needed to determine whether the presence of renal simple cysts can be considered as a risk factor for AAA.