Pulmonary arterial enlargement and acute exacerbations of COPD

Personalizing and targeting therapy for COPD: the role of molecular and clinical biomarkers

Chronic obstructive pulmonary disease (COPD) is a heterogeneous disease characterized by persistent airflow limitation. It is the third leading cause of death worldwide, and there are currently no curative strategies for this disease. Many factors contribute to COPD susceptibility, progression and exacerbations. These include cigarette smoking, environmental and occupational pollutants, respiratory infections and comorbidities. As the clinical phenotypes of COPD are so variable, it has been difficult to devise an individualized treatment plan for patients with this complex chronic disease. This review will highlight how potential clinical, inflammatory, genomic and epigenomic biomarkers for COPD could be used to personalize treatment, leading to improved disease management and prevention for our patients.

Acute decompensated heart failure is routinely treated as a cardiopulmonary syndrome

BACKGROUND

Heart failure as recognized and treated in typical practice may represent a complex condition that defies discrete categorizations. To illuminate this complexity, we examined treatment strategies for patients hospitalized and treated for decompensated heart failure. We focused on the receipt of medications appropriate for other acute conditions associated with shortness of breath including acute asthma, pneumonia, and exacerbated chronic obstructive pulmonary disease.

METHODS AND RESULTS

Using Premier Perspective(®), we studied adults hospitalized with a principal discharge diagnosis of heart failure and evidence of acute heart failure treatment from 2009-2010 at 370 US hospitals. We determined treatment with acute respiratory therapies during the initial 2 days of hospitalization and daily during hospital days 3-5. We also calculated adjusted odds of in-hospital death, admission to the intensive care unit, and late intubation (intubation after hospital day 2). Among 164,494 heart failure hospitalizations, 53% received acute respiratory therapies during the first 2 hospital days: 37% received short-acting inhaled bronchodilators, 33% received antibiotics, and 10% received high-dose corticosteroids. Of these 87,319 hospitalizations, over 60% continued receiving respiratory therapies after hospital day 2. Respiratory treatment was more frequent among the 60,690 hospitalizations with chronic lung disease. Treatment with acute respiratory therapy during the first 2 hospital days was associated with higher adjusted odds of all adverse outcomes.

CONCLUSIONS

Acute respiratory therapy is administered to more than half of patients hospitalized with and treated for decompensated heart failure. Heart failure is therefore regularly treated as a broader cardiopulmonary syndrome rather than as a singular cardiac condition.

Computed tomographic measures of pulmonary vascular morphology in smokers and their clinical implications

RATIONALE

Angiographic investigation suggests that pulmonary vascular remodeling in smokers is characterized by distal pruning of the blood vessels.

OBJECTIVES

Using volumetric computed tomography scans of the chest we sought to quantitatively evaluate this process and assess its clinical associations.

METHODS

Pulmonary vessels were automatically identified, segmented, and measured. Total blood vessel volume (TBV) and the aggregate vessel volume for vessels less than 5 mm(2) (BV5) were calculated for all lobes. The lobe-specific BV5 measures were normalized to the TBV of that lobe and the nonvascular tissue volume (BV5/T(issue)V) to calculate lobe-specific BV5/TBV and BV5/T(issue)V ratios. Densitometric measures of emphysema were obtained using a Hounsfield unit threshold of -950 (%LAA-950). Measures of chronic obstructive pulmonary disease severity included single breath measures of diffusing capacity of carbon monoxide, oxygen saturation, the 6-minute-walk distance, St George's Respiratory Questionnaire total score (SGRQ), and the body mass index, airflow obstruction, dyspnea, and exercise capacity (BODE) index.

MEASUREMENTS AND MAIN RESULTS

The %LAA-950 was inversely related to all calculated vascular ratios. In multivariate models including age, sex, and %LAA-950, lobe-specific measurements of BV5/TBV were directly related to resting oxygen saturation and inversely associated with both the SGRQ and BODE scores. In similar multivariate adjustment lobe-specific BV5/T(issue)V ratios were inversely related to resting oxygen saturation, diffusing capacity of carbon monoxide, 6-minute-walk distance, and directly related to the SGRQ and BODE.

CONCLUSIONS

Smoking-related chronic obstructive pulmonary disease is characterized by distal pruning of the small blood vessels (<5 mm(2)) and loss of tissue in excess of the vasculature. The magnitude of these changes predicts the clinical severity of disease.

Endothelin receptor antagonists attenuate the inflammatory response of human pulmonary vascular smooth muscle cells to bacterial endotoxin

Bacterial infections induce exacerbations in chronic lung diseases, e.g., chronic obstructive pulmonary disease (COPD), by enhancing airway inflammation. Exacerbations are frequently associated with right heart decompensation and accelerate disease progression. Endothelin receptor antagonists (ERAs) might have therapeutic potential as pulmonary vasodilators and anti-inflammatory agents, but utility in exacerbations of chronic lung diseases is unknown. We hypothesized that cytokine releases induced by lipopolysaccharide (LPS), the major bacterial trigger of inflammation, are reduced by ERAs in pulmonary vascular smooth muscle cells (PVSMCs). Ex vivo cultivated human PVSMCs were preincubated with the endothelin-A-receptor selective inhibitor ambrisentan, with the endothelin-B-receptor selective inhibitor BQ788 [sodium (2R)-2-{[(2S)-2-({[(2R,6S)-2,6-dimethyl-1-piperidinyl]carbonyl}amino)-4,4-dimethylpentanoyl][1-(methoxycarbonyl)-d-tryptophyl]amino}hexanoate], or with the dual blocker bosentan before stimulation with smooth LPS (S-LPS), rough LPS (Re-LPS), or a mixture of long and short forms (M-LPS). Expression of cytokines and LPS receptors (TLR4, CD14) were analyzed via enzyme-linked immunosorbent assay (ELISA) and/or quantitative reverse transcriptase polymerase chain reaction (qRT-PCR). All LPS forms induced interleukin (IL)-6-, IL-8-, and granulocyte macrophage-colony stimulating factor (GM-CSF) release. Bosentan and BQ788 inhibited M-LPS-induced release of all cytokines and soluble CD14 (sCD14) but not TLR4 expression. Ambrisentan blocked M-LPS-induced IL-6 release but not IL-8, GM-CSF, or LPS receptors. IL-8 release induced by S-LPS, which requires CD14 to activate TLR4, was blocked by bosentan and BQ788. IL-8 release induced by Re-LPS, which does not require CD14 to activate TLR4, was insensitive to both bosentan and BQ788. In conclusion, PVSMCs contribute to inflammation in bacteria-induced exacerbations of chronic lung diseases. Inhibition of the endothelin-B receptor suppresses cytokine release induced by long/smooth LPS attributable to sCD14 downregulation. ERAs, particularly when targeting the endothelin-B receptor, might have therapeutic utility in exacerbations of chronic lung diseases.

Epicardial adipose tissue in patients with chronic obstructive pulmonary disease

RATIONALE

Epicardial Adipose Tissue (EAT) volume as determined by chest computed tomography (CT) is an independent marker of cardiovascular events in the general population. COPD patients have an increased risk of cardiovascular disease, however nothing is known about the EAT volume in this population.

OBJECTIVES

To assess EAT volume in COPD and explore its association with clinical and physiological variables of disease severity.

METHODS

We measured EAT using low-dose CT in 171 stable COPD patients and 70 controls matched by age, smoking history and BMI. We determined blood pressure, cholesterol, glucose and HbA1c levels, microalbuminuria, lung function, BODE index, co-morbidity index and coronary artery calcium score (CAC). EAT volume were compared between groups. Uni and multivariate analyses explored the relationship between EAT volume and the COPD related variables.

RESULTS

COPD patients had a higher EAT volume [143.7 (P25-75, 108.3-196.6) vs 129.1 (P25-75, 91.3-170.8) cm(3), p = 0.02)] and the EAT volume was significantly associated with CAC (r = 0.38, p<0.001) and CRP (r = 0.32, p<0.001) but not with microalbuminuria (r = 0.12, p = 0.13). In COPD patients, EAT volume was associated with: age, pack-years, BMI, gender, FEV1%, 6 MWD, MMRC and HTN. Multivariate analysis showed that only pack-years (B = 0.6, 95% CI: 0.5-1.3), BMI (B = 7.8, 95% CI: 5.7-9.9) and 6 MWD (B = -0.2, 95% CI: -0.3--0.1), predicted EAT volume.

CONCLUSIONS

EAT volume is increased in COPD patients and is independently associated with smoking history, BMI and exercise capacity, all modifiable risk factors of future cardiovascular events. EAT volume could be a non-invasive marker of COPD patients at high risk for future cardiovascular events.

Daily step count predicts acute exacerbations in a US cohort with COPD

Background

COPD is characterized by variability in exercise capacity and physical activity (PA), and acute exacerbations (AEs). Little is known about the relationship between daily step count, a direct measure of PA, and the risk of AEs, including hospitalizations.

Methods

In an observational cohort study of 169 persons with COPD, we directly assessed PA with the StepWatch Activity Monitor, an ankle-worn accelerometer that measures daily step count. We also assessed exercise capacity with the 6-minute walk test (6MWT) and patient-reported PA with the St. George's Respiratory Questionnaire Activity Score (SGRQ-AS). AEs and COPD-related hospitalizations were assessed and validated prospectively over a median of 16 months.

Results

Mean daily step count was 5804±3141 steps. Over 209 person-years of observation, there were 263 AEs (incidence rate 1.3±1.6 per person-year) and 116 COPD-related hospitalizations (incidence rate 0.56±1.09 per person-year). Adjusting for FEV₁ % predicted and prednisone use for AE in previous year, for each 1000 fewer steps per day walked at baseline, there was an increased rate of AEs (rate ratio 1.07; 95%CI = 1.003–1.15) and COPD-related hospitalizations (rate ratio 1.24; 95%CI = 1.08–1.42). There was a significant linear trend of decreasing daily step count by quartiles and increasing rate ratios for AEs (P = 0.008) and COPD-related hospitalizations (P = 0.003). Each 30-meter decrease in 6MWT distance was associated with an increased rate ratio of 1.07 (95%CI = 1.01–1.14) for AEs and 1.18 (95%CI = 1.07–1.30) for COPD-related hospitalizations. Worsening of SGRQ-AS by 4 points was associated with an increased rate ratio of 1.05 (95%CI = 1.01–1.09) for AEs and 1.10 (95%CI = 1.02–1.17) for COPD-related hospitalizations.

Conclusions

Lower daily step count, lower 6MWT distance, and worse SGRQ-AS predict future AEs and COPD–related hospitalizations, independent of pulmonary function and previous AE history. These results support the importance of assessing PA in patients with COPD, and provide the rationale to promote PA as part of exacerbation-prevention strategies.

Chronic obstructive pulmonary disease

The global prevalence of physiologically defined chronic obstructive pulmonary disease (COPD) in adults aged >40 yr is approximately 9-10 per cent. Recently, the Indian Study on Epidemiology of Asthma, Respiratory Symptoms and Chronic Bronchitis in Adults had shown that the overall prevalence of chronic bronchitis in adults >35 yr is 3.49 per cent. The development of COPD is multifactorial and the risk factors of COPD include genetic and environmental factors. Pathological changes in COPD are observed in central airways, small airways and alveolar space. The proposed pathogenesis of COPD includes proteinase-antiproteinase hypothesis, immunological mechanisms, oxidant-antioxidant balance, systemic inflammation, apoptosis and ineffective repair. Airflow limitation in COPD is defined as a postbronchodilator FEV1 (forced expiratory volume in 1 sec) to FVC (forced vital capacity) ratio <0.70. COPD is characterized by an accelerated decline in FEV1. Co morbidities associated with COPD are cardiovascular disorders (coronary artery disease and chronic heart failure), hypertension, metabolic diseases (diabetes mellitus, metabolic syndrome and obesity), bone disease (osteoporosis and osteopenia), stroke, lung cancer, cachexia, skeletal muscle weakness, anaemia, depression and cognitive decline. The assessment of COPD is required to determine the severity of the disease, its impact on the health status and the risk of future events (e.g., exacerbations, hospital admissions or death) and this is essential to guide therapy. COPD is treated with inhaled bronchodilators, inhaled corticosteroids, oral theophylline and oral phosphodiesterase-4 inhibitor. Non pharmacological treatment of COPD includes smoking cessation, pulmonary rehabilitation and nutritional support. Lung volume reduction surgery and lung transplantation are advised in selected severe patients. Global strategy for the diagnosis, management and prevention of Chronic Obstructive Pulmonary Disease guidelines recommend influenza and pneumococcal vaccinations.

Clinical phenotypes of chronic obstructive pulmonary disease and asthma: recent advances

Asthma and chronic obstructive pulmonary disease (COPD) are prevalent obstructive lung diseases, both of which are characterized by airflow limitation. Although both represent distinct pathogenic entities, there can be significant clinical and physiologic overlap between the 2 disorders, creating potential management difficulties for clinicians. Although practice guidelines for both conditions outline diagnostic and management strategies, asthma and COPD are highly heterogeneous, and the symptoms of many patients remain poorly controlled despite adherence to current guidelines. Recent advances in phenotyping studies have elucidated heterogeneity in these airway diseases and might represent the best opportunity to enhance diagnosis, predict outcomes, and personalize treatments in patients with asthma and those with COPD. This review will focus on recent advances in describing phenotypic heterogeneity in asthma and COPD, including the evaluation of multiple clinical variables, molecular biomarkers, physiologic and radiologic data, and factors associated with disease progression and frequent exacerbations.