Systemic and upper and lower airway inflammation at exacerbation of chronic obstructive pulmonary disease

Soluble triggering receptor expressed on myeloid cells 1 is released in patients with stable chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is increasingly recognized as a systemic disease that is associated with increased serum levels of markers of systemic inflammation. The triggering receptor expressed on myeloid cells 1 (TREM-1) is a recently identified activating receptor on neutrophils, monocytes, and macrophage subsets. TREM-1 expression is upregulated by microbial products such as the toll-like receptor ligand lipoteichoic acid of Gram-positive or lipopolysaccharides of Gram-negative bacteria. In the present study, sera from 12 COPD patients (GOLD stages I-IV, FEV1 51 +/- 6%) and 10 healthy individuals were retrospectively analyzed for soluble TREM-1 (sTREM-1) using a newly developed ELISA. In healthy subjects, sTREM-1 levels were low (median 0.25 ng/mL, range 0-5.9 ng/mL). In contrast, levels of sTREM-1 in sera of COPD patients were significantly increased (median 11.68 ng/mL, range 6.2-41.9 ng/mL, P<.05). Furthermore, serum levels of sTREM-1 showed a significant negative correlation with lung function impairment. In summary, serum concentrations of sTREM-1 are increased in patients with COPD. Prospective studies are warranted to evaluate the relevance of sTREM-1 as a potential marker of the disease in patients with COPD.

Mechanisms of cigarette smoke-induced COPD: insights from animal models

Cigarette smoke-induced animal models of chronic obstructive pulmonary disease support the protease-antiprotease hypothesis of emphysema, although which cells and proteases are the crucial actors remains controversial. Inhibition of either serine or metalloproteases produces significant protection against emphysema, but inhibition is invariably accompanied by decreases in the inflammatory response to cigarette smoke, suggesting that these inhibitors do more than just prevent matrix degradation. Direct anti-inflammatory interventions are also effective against the development of emphysema, as are antioxidant strategies; the latter again decrease smoke-induced inflammation. There is increasing evidence for autoimmunity, perhaps directed against matrix components, as a driving force in emphysema. There is intriguing but controversial animal model evidence that failure to repair/failure of lung maintenance also plays a role in the pathogenesis of emphysema. Cigarette smoke produces small airway remodeling in laboratory animals, possibly by direct induction of fibrogenic growth factors in the airway wall, and also produces pulmonary hypertension, at least in part through direct upregulation of vasoactive mediators in the intrapulmonary arteries. Smoke exposure causes goblet cell metaplasia and excess mucus production in the small airways and proximal trachea, but these changes are not good models of either chronic bronchitis or acute exacerbations. Emphysema, small airway remodeling, pulmonary hypertension, and mucus production appear to be at least partially independent processes that may require different therapeutic approaches.

Pseudomonas aeruginosa in chronic obstructive pulmonary disease

RATIONALE

Pseudomonas aeruginosa is isolated from adults with chronic obstructive pulmonary disease (COPD) in cross-sectional studies. However, patterns of carriage and the role of P. aeruginosa in COPD are unknown.

OBJECTIVES

To elucidate carriage patterns, phenotypes of strains, clinical manifestations, and the antibody response to P. aeruginosa in COPD.

METHODS

A prospective study of adults with COPD was conducted. Isolates of P. aeruginosa were subjected to genotypic and phenotypic analysis. Sputum samples were studied for P. aeruginosa DNA, and immune responses were assayed.

MEASUREMENTS AND MAIN RESULTS

We analyzed longitudinal clinical data, sputum cultures, pulsed-field gel electrophoresis of bacterial DNA, polymerase chain reaction of sputum, and immunoblot assays of serum. Fifty-seven episodes of acquisition of strains of P. aeruginosa were observed in 39 of 126 patients over 10 years. Acquisition of a new strain was associated with exacerbation. Thirty-one episodes of carriage were followed by clearance of the strain; 16 were of short (<1 mo) duration. Thirteen strains demonstrated persistence, and 13 strains were of indeterminate duration. Six strains were mucoid and were more likely to persist than nonmucoid strains (P = 0.005). Antibody responses developed in 53.8% of persistent carriage and in only 9.7% of short-term carriage episodes (P = 0.003). Antibiotics did not account for clearance.

CONCLUSIONS

Two distinct patterns of carriage by P. aeruginosa were observed: (1) short-term colonization followed by clearance and (2) long-term persistence. Mucoid strains showed persistence. Acquisition of P. aeruginosa is associated with the occurrence of an exacerbation. Serum antibody responses do not mediate clearance of P. aeruginosa.

Infections in chronic lung diseases

Chronic lung diseases are prevalent worldwide and cause significant mortality and suffering. This article discusses infections that occur in three chronic lung diseases: chronic obstructive pulmonary disease, bronchiectasis, and cystic fibrosis. Rather than discussing the role of infections as etiology of these diseases, this article focuses on infections that occur in the background of established chronic lung disease.

Role of macrolide therapy in chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is a leading cause of death and disability worldwide. The Global Burden of Disease study has concluded that COPD will become the third leading cause of death worldwide by 2020, and will increase its ranking of disability-adjusted life years lost from 12th to 5th. Acute exacerbations of COPD (AECOPD) are associated with impaired quality of life and pulmonary function. More frequent or severe AECOPDs have been associated with especially markedly impaired quality of life and a greater longitudinal loss of pulmonary function. COPD and AECOPDs are characterized by an augmented inflammatory response. Macrolide antibiotics are macrocyclical lactones that provide adequate coverage for the most frequently identified pathogens in AECOPD and have been generally included in published guidelines for AECOPD management. In addition, they exert broad-ranging, immunomodulatory effects both in vitro and in vivo, as well as diverse actions that suppress microbial virulence factors. Macrolide antibiotics have been used to successfully treat a number of chronic, inflammatory lung disorders including diffuse panbronchiolitis, asthma, noncystic fibrosis associated bronchiectasis, and cystic fibrosis. Data in COPD patients have been limited and contradictory but the majority hint to a potential clinical and biological effect. Additional, prospective, controlled data are required to define any potential treatment effect, the nature of this effect, and the role of bronchiectasis, baseline colonization, and other cormorbidities.

Investigating new standards for prophylaxis in reduction of exacerbations--the INSPIRE study methodology

Bronchodilators, including long-acting beta(2)-adrenoceptor agonists and anticholinergic bronchodilators, are effective in the treatment of chronic obstructive pulmonary disease. Evidence suggests that the addition of a long-acting beta(2)-agonist to an inhaled corticosteroid is associated with a reduced rate of exacerbations compared with either treatment alone or placebo. However, it is not known whether a long-acting beta(2)-agonist/inhaled corticosteroid combination is more effective than an anticholinergic bronchodilator alone in reducing exacerbations. The Investigating New Standards for Prophylaxis In Reduction of Exacerbations (INSPIRE) trial will study salmeterol (a long-acting beta(2)-agonist) in combination with fluticasone propionate (an inhaled corticosteroid) compared with tiotropium bromide (an anticholinergic bronchodilator) in patients with moderate-to-severe chronic obstructive pulmonary disease. The INSPIRE study is a multicentre, randomised, double-blind, double dummy, parallel group study conducted over 104 weeks. This is the first study to use two parallel definitions of an exacerbation; an event-based exacerbation is defined as one that requires use of healthcare resources, including additional treatment and hospitalization, whereas a symptom-based exacerbation is defined as one that satisfies the 1987 Anthonisen criteria. It is also the first study to compare the long-term effects of salmeterol/fluticasone propionate with tiotropium bromide on the rate of event-based exacerbations. Endpoints include rate of exacerbations (primary endpoint), time to first exacerbation, and duration of exacerbations. Health outcomes will be assessed via the St George's Respiratory Questionnaire. If the innovative methodology of utilizing 2 definitions of exacerbation proves successful, it will set the benchmark for future studies in chronic obstructive pulmonary disease.

Inflammatory profile of new bacterial strain exacerbations of chronic obstructive pulmonary disease

RATIONALE

Whether the airway and systemic inflammatory profile in bacterial exacerbations of chronic obstructive pulmonary disease (COPD) is distinct from nonbacterial exacerbations is unclear. Previous studies have not used molecular typing of bacterial pathogens, which is required to accurately define bacterial infection in COPD. The relationship between clinical severity and course of exacerbation and inflammation is also not fully understood.

OBJECTIVES

To determine if (1) systemic and airway inflammation is distinct in new bacterial strain exacerbations and (2) clinical severity and resolution of exacerbations is related to airway and systemic inflammation.

METHODS

In a prospective longitudinal cohort study in COPD, sputum and serum samples obtained before, at, and following exacerbations during a 2-year period were studied.

MEASUREMENTS AND MAIN RESULTS

Clinical information, molecular typing of bacterial pathogens, sputum IL-8, tumor necrosis factor (TNF)-alpha and neutrophil elastase, and serum C-reactive protein. From 46 patients, 177 exacerbations were grouped as new strain, preexisting strain, other pathogen, and pathogen negative. New strain exacerbations were associated with significantly greater increases from baseline in sputum TNF-alpha and neutrophil elastase, and in serum C-reactive protein compared with the other three groups. Increases in inflammatory markers were similar among the other three groups. Clinical resolution was accompanied by resolution of inflammation to preexacerbation levels, whereas persistent symptoms were paralleled by persistently elevated inflammation. Clinical exacerbation severity was significantly correlated with levels of all four markers.

CONCLUSIONS

Neutrophilic airway inflammation and systemic inflammation are more intense with well-defined bacterial exacerbations than with nonbacterial exacerbations. Clinical course of exacerbation and inflammation are closely linked.

Pathogen-directed therapy in acute exacerbations of chronic obstructive pulmonary disease

Acute exacerbations of chronic obstructive pulmonary disease (COPD) are important events in the natural history of this chronic lung disorder. These events can be caused by a large number of infectious and noninfectious agents and are associated with an increased local and systemic inflammatory response. Their frequency and severity have been linked to progressive deterioration in lung function and health status. Infectious pathogens ranging from viral to atypical and typical bacteria have been implicated in the majority of episodes. Most therapeutic regimens to date have emphasized broad, nonspecific approaches to bronchoconstriction and pulmonary inflammation. Increasingly, therapy that targets specific etiologic pathogens has been advocated. These include clinical and laboratory-based methods to identify bacterial infections. Further additional investigation has suggested specific pathogens within this broad class. As specific antiviral therapies become available, better diagnostic approaches to identify specific pathogens will be required. Furthermore, prophylactic therapy for at-risk individuals during high-risk times may become a standard therapeutic approach. As such, the future will likely include aggressive diagnostic algorithms based on the combination of clinical syndromes and rapid laboratory modalities to identify specific causative bacteria or viruses.

Serum amyloid a is a biomarker of acute exacerbations of chronic obstructive pulmonary disease

RATIONALE

Much of the total disease burden and cost of chronic obstructive pulmonary disease (COPD) is associated with acute exacerbations of COPD (AECOPD). Serum amyloid A (SAA) is a novel candidate exacerbation biomarker identified by proteomic screening.

OBJECTIVES

To assess SAA as a biomarker of AECOPD.

METHODS

Biomarkers were assessed (1) cross-sectionally (stable vs. AECOPD; 62 individuals) and (2) longitudinally with repeated measures (baseline vs. AECOPD vs. convalescence; 78 episodes in 37 individuals). Event severity was graded (I, ambulatory; II, hospitalized; III, respiratory failure) based on consensus guidelines.

MEASUREMENTS AND MAIN RESULTS

Presumptively newly acquired pathogens were associated with onset of symptomatic AECOPD. In the cross-sectional study, both SAA and C-reactive protein (CRP) were elevated at AECOPD onset compared with stable disease (SAA median, 7.7 vs. 57.6 mg/L; P < 0.01; CRP median, 4.6 vs. 12.5 mg/L; P < 0.01). Receiver operator characteristics analysis was used to generate area-under-curve values for event severity. SAA discriminated level II/III events (SAA, 0.88; 95% confidence interval, 0.80-0.94 vs. CRP, 0.80; 95% confidence interval, 0.70-0.87; P = 0.05). Combining SAA or CRP with major symptoms (Anthonisen criteria, dyspnea) did not further improve the prediction model for severe episodes. IL-6 and procalcitonin were not informative.

CONCLUSIONS

SAA is a novel blood biomarker of AECOPD that is more sensitive than CRP alone or in combination with dyspnea. SAA may offer new insights into the pathogenesis of AECOPD.

Acute exacerbations of chronic bronchitis in elderly patients: pathogenesis, diagnosis and management

Chronic bronchitis (CB) is a disorder that is characterised by chronic mucus production. This disorder is called chronic obstructive pulmonary disease (COPD) when airflow obstruction is present. The majority of patients with COPD, which often goes undiagnosed or inadequately treated in the elderly, have symptoms consistent with CB. The clinical course of CB is usually punctuated by periodic acute exacerbations linked to infections caused by viral and typical or atypical bacterial pathogens. Acute exacerbations of chronic bronchitis (AECB) often lead to a decline in lung function and poor quality of life in association with increased risk of mortality and a significant economic impact on the healthcare system and society because of the direct costs of hospitalisations. In elderly individuals with COPD, co-morbidities play a vital role as determinants of health status and prognosis. Failure to eradicate infecting pathogens contributes to persistence of infection and inflammation that requires repeated courses of therapy and hospitalisation. Stratifying patients with AECB according to symptoms, degree of pulmonary function impairment and risk factors for poor outcome can help clinicians choose empirical antimicrobial chemotherapy regimens that are most likely to result in treatment success. Failure to cover likely pathogens associated with episodes of AECB can lead to lengthy hospital admissions and significant declines in functional status for elderly patients. Fluoroquinolones may provide the best therapeutic option for elderly patients with COPD who have complicated underlying CB but who are sufficiently stable to be treated in the outpatient setting. Optimised treatment for stable outpatients with CB may diminish the frequency of AECB, and effective antimicrobial therapy for AECB episodes can significantly diminish healthcare costs and maintain quality of life in the elderly patient.

The Biology of a Chronic Obstructive Pulmonary Disease Exacerbation

Much of the morbidity and mortality in chronic obstructive pulmonary disease relates to symptomatic deteriorations in respiratory health termed exacerbations. Exacerbations also are associated with changes in lung function and both airway and systemic inflammation. The most common causes of exacerbation are micro-organisms: respiratory viruses such as rhinovirus, and various bacterial species. This article reviews and discusses current understanding of the biology of exacerbations, considering the definition, epidemiology, etiology, and the nature and evolution of the changes in symptoms, lung function, and inflammation that characterize these important events.

COPD exacerbations: defining their cause and prevention

Exacerbations of chronic obstructive pulmonary disease (COPD) are episodes of worsening of symptoms, leading to substantial morbidity and mortality. COPD exacerbations are associated with increased airway and systemic inflammation and physiological changes, especially the development of hyperinflation. They are triggered mainly by respiratory viruses and bacteria, which infect the lower airway and increase airway inflammation. Some patients are particularly susceptible to exacerbations, and show worse health status and faster disease progression than those who have infrequent exacerbations. Several pharmacological interventions are effective for the reduction of exacerbation frequency and severity in COPD such as inhaled steroids, long-acting bronchodilators, and their combinations. Non-pharmacological therapies such as pulmonary rehabilitation, self-management, and home ventilatory support are becoming increasingly important, but still need to be studied in controlled trials. The future of exacerbation prevention is in assessment of optimum combinations of pharmacological and non-pharmacological therapies that will result in improvement of health status, and reduction of hospital admission and mortality associated with COPD.

Nasal and sinus inflammation in chronic obstructive pulmonary disease

Epidemiologic studies suggest that as many as 75% of patients with COPD have concomitant nasal symptoms and more than 1/3 of patients with sinusitis also have lower airway symptoms of asthma or COPD. Because the inflammatory response of the upper and lower airways are similar, and both sites have a similar exposure to allergens and irritants, it is not surprising that rhinitis or sinusitis would coexist with COPD. Possible mechanisms of combined upper and lower airway dysfunction include the so-called nasal-bronchial reflex, inflammation caused by smoking, mouth breathing caused by nasal obstruction, and pulmonary aspiration of nasal contents. Patients with chronic sinusitis commonly have nonspecific bronchial hyperresponsiveness, suggesting a neural reflex. Postnasal drainage of nasal inflammatory mediators during sleep also may increase lower airway responsiveness. Therapy of nasal and sinus disease is associated with improved pulmonary function in patients with COPD.

Systemic inflammation and lung function in young adults

BACKGROUND

Impaired lung function is associated with systemic inflammation and is a risk factor for cardiovascular disease in older adults. It is unknown when these associations emerge and to what extent they are mediated by smoking, chronic airways disease, and/or established atherosclerosis. We explored the association between the forced expiratory volume in one second (FEV(1)) and the systemic inflammatory marker C-reactive protein (CRP) in young adults.

METHODS

Associations between spirometric lung function and blood CRP were assessed in a population based birth cohort of approximately 1000 New Zealanders at ages 26 and 32 years. Analyses adjusted for height and sex to account for differences in predicted lung function and excluded pregnant women.

RESULTS

There were significant inverse associations between FEV(1) and CRP at both ages. Similar results were found for the forced vital capacity. These associations were similar in men and women and were independent of smoking, asthma, and body mass index.

CONCLUSIONS

Reduced lung function is associated with systemic inflammation in young adults. This association is not related to smoking, asthma, or obesity. The reasons for the association are unexplained, but the findings indicate that the association between lower lung function and increased inflammation predates the development of either chronic lung disease or clinically significant atherosclerosis. The association between poor lung function and cardiovascular disease may be mediated by an inflammatory mechanism.

Systemic inflammation and systemic oxidative stress in patients with acute exacerbations of COPD

BACKGROUND

In patients with chronic obstructive pulmonary disease (COPD), the inflammatory processes and oxidative stress are closely linked in the lung compartment. However, the relationships between systemic inflammation and parameters of oxidative stress in the systemic circulation during acute exacerbations of COPD remain to be explored.

OBJECTIVE

To analyze relationships between erythrocytic glutathione peroxidase (GPx), a marker of systemic oxidative stress, and parameters reflecting systemic inflammation, such as circulating neutrophils, C-reactive protein (CRP), and interleukin (IL)-6, in patients with acute exacerbations of COPD.

PATIENTS AND METHODS

We measured erythrocytic GPx activity, circulating neutrophil count, and serum high-sensitivity (hs) CRP and IL-6 in 177 patients admitted to the hospital due to an acute exacerbation of COPD (91 males, mean age 66.8+/-0.9 years, mean FEV1 45.3+/-1.3% predicted).

RESULTS

From GOLD Stage II to Stage III and IV, erythrocytic GPx activity significantly decreased [mean+/-SEM: from 44.3+/-1.7 U/g Hb to 40.8+/-1.1 U/g Hb and to 38.4+/-1.5 U/g Hb, p = 0.037], while serum hsCRP increased [median (25th, 75th percentile): from 9.6 (3.0, 23.0) mg/l to 23.3 (6.4, 46.8) mg/l, and to 26.7 (6.5, 117.2) mg/l, p = 0.004]. Erythrocytic GPx activity was significantly inversely related to both, log neutrophil count (r = -0.219, p = 0.003) and log hsCRP (r = -0.199, p = 0.008).

CONCLUSIONS

Our study suggests an association between systemic inflammation and systemic oxidative stress reflected by erythrocytic GPx in patients with acute exacerbations of COPD.

Corticosteroids and beta2 agonists differentially regulate rhinovirus-induced interleukin-6 via distinct Cis-acting elements

Interleukin-6 (IL-6) is a proinflammatory cytokine up-regulated by rhinovirus infection during acute exacerbations of asthma and chronic obstructive pulmonary disease. The role of IL-6 during exacerbations is unclear; however, it is believed IL-6 could contribute to airway and systemic inflammation. In this study we investigate the effects of common asthma treatments fluticasone propionate and beta(2) agonists salmeterol and salbutamol on IL-6 production in BEAS-2B and primary bronchial epithelial cells. Salmeterol and salbutamol enhanced rhinovirus- and IL-1beta-induced IL-6 production; however, fluticasone treatment caused a reduction of IL-6 protein and mRNA. Combined activity of salmeterol and fluticasone at equimolar concentrations had no effect on rhinovirus or IL-1beta induction of IL-6. The induction of IL-6 by salmeterol was dependent upon the beta(2) receptor and could also be induced by cAMP or cAMP-elevating agents forskolin and rolipram. Using transfection of IL-6 promoter reporter constructs, dominant negative mutants, and electromobility shift assays, it was found that NF-kappaB was the only transcription factor required for rhinovirus induction of IL-6 gene expression. Salmeterol caused an augmentation of rhinovirus-induced promoter activation via a mechanism dependent upon the c/EBP and/or CRE (cyclic AMP response element) cis-acting sites. The suppressive effect of FP was dependent upon distinct glucocorticoid response element sequences proximal to the transcriptional start site within the IL-6 promoter. The data demonstrate that beta(2) agonists can augment IL-6 expression by other stimuli in an additive manner via cyclic AMP and that the negative effect of steroids is mediated by glucocorticoid response elements within the IL-6 promoter.

Chronic obstructive pulmonary disease exacerbation and risk of pulmonary embolism

Pulmonary embolism is not a common feature in patients with chronic obstructive pulmonary disease with uncomplicated exacerbations

6: Rhinitis and asthma: united airway disease

United airway disease is characterised by inflammation of the respiratory tract, in which asthma and rhinitis are the upper and lower respiratory tract manifestations, respectively, of the same disease process. Irrespective of cause, the upper and lower respiratory tract manifestations are characterised by a systemic inflammatory response. Patients with rhinitis or asthma should always be assessed for coexistent disease in the reciprocal area. Treatment of upper airway disease can modify the severity of lower airway disease and vice versa. The potential for early treatment of allergic rhinitis to prevent progression to asthma merits further study.

The neutrophil in chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is a complex, heterogeneous collection of conditions characterized by irreversible expiratory airflow limitation. The disease involves a multifaceted progressive inflammatory process leading to the development of mucus hypersecretion, tissue destruction, and disruption to the normal repair and defense mechanisms. The result is increased resistance to airflow in small conducting airways, change in lung compliance, and the premature collapse of airways during expiration that leads to air trapping. Neutrophils are necessary in healthy lungs; they are an important component of innate immunity, protecting healthy individuals against infection. However, in COPD, they play a role in the destructive processes that characterize the disease. They can be responsible for significant damage when they accumulate at sites of inflammation and are harmful to healthy tissue. In recent years, increased understanding of the role of neutrophils has led to improved knowledge of the pathogenesis of COPD and allowed new avenues of treatment to be investigated.

Anemia in COPD: Should It Be Taken Into Consideration?

Recent recognition of the importance of nonpulmonary signs and symptoms in the management and prognosis of chronic obstructive pulmonary disease (COPD) has led to a shift in the focus of diagnostic and therapeutic strategies to encompass these aspects. We no longer concentrate on assessing a single functional variable (forced expiratory volume in 1 second) as a predictor of survival in these patients. Most of the research undertaken to date into COPD-related systemic disorders has targeted weight loss, muscular dysfunction, osteoporosis, and cardiovascular disease. However, the abnormal inflammatory response associated with COPD may provoke other disorders such as anemia. Moreover, comorbid anemia has been shown to be an independent predictor of mortality in several chronic diseases including cancer and heart failure. Anemia is, therefore, an entity that should be taken into consideration in the overall management of respiratory disease because it may have a clear detrimental impact on various aspects of the patient s health, including dyspnea, exercise tolerance, and quality of life. There is a growing body of literature on the relationship between anemia and COPD. Our aim is to briefly review the pathophysiologic aspects of this association before going on to discuss some of the most recent evidence published.

Systemic inflammation and mortality in chronic obstructive pulmonary diseaseThis paper is one of a selection of papers published in this Special Issue, entitled Young Investigators' Forum

Cardiovascular diseases and cancer (especially lung cancer) are leading causes of morbidity and mortality in patients with chronic obstructive pulmonary disease (COPD). Some have implicated systemic inflammation, which is commonly observed in COPD, as the potential mechanistic bridge between COPD and these disorders. This concept has been supported by animal studies especially in rabbits, which have clearly demonstrated the effect of local lung inflammation on systemic inflammation and on the progression of atherosclerosis and by cross-sectional population-based studies, which have shown a significant relationship between systemic inflammation, as measured by circulating C-reactive protein (CRP) and the risk of cardiovascular diseases in COPD patients. These data have been further extended by a recent study that has elucidated the temporal nature of the relationship between systemic inflammation and the risk of cardiovascular events and cancer in COPD patients. This study showed that baseline CRP levels predicted the incidence of cardiovascular events and cancer-specific mortality over 7 to 8 years of follow-up. CRP levels also predicted all-cause mortality. Collectively, these data indicate that systemic inflammation may play an important role in mediating the extra-pulmonary complications of COPD. Systemic inflammation may contribute substantially to the overall morbidity and mortality of COPD patients.

Airway inflammation contributes to health status in COPD: a cross-sectional study

Background

Chronic obstructive pulmonary disease (COPD) is characterized by irreversible airflow limitation and airway inflammation, accompanied by decreased health status. It is still unknown which factors are responsible for the impaired health status in COPD. We postulated that airway inflammation negatively contributes to health status in COPD.

Methods

In 114 COPD patients (99 male, age: 62 ± 8 yr, 41 [31–55] pack-years, no inhaled or oral corticosteroids, postbronchodilator FEV₁: 63 ± 9% pred, FEV₁/IVC: 48 ± 9%) we obtained induced sputum and measured health status (St. George's respiratory questionnaire (SGRQ)), postbronchodilator FEV₁, hyperinflation (RV/TLC), and airway hyperresponsiveness to methacholine (PC₂₀). Sputum was induced by hypertonic saline and differential cell counts were obtained in 102 patients.

Results

Univariate analysis showed that SGRQ total and symptom score were positively associated with % sputum macrophages (r = 0.20, p = 0.05; and r = 0.20, p = 0.04, respectively). Multiple regression analysis confirmed these relationships, providing significant contributions of % sputum macrophages (B = 0.25, p = 0.021) and RV/TLC (B = 0.60, p = 0.002) to SGRQ total score. Furthermore, SGRQ symptom score was associated with % sputum macrophages (B = 0.30, p = 0.03) and RV/TLC (B = 0.48, p = 0.044), whilst SGRQ activity score was associated with % sputum macrophages (B = 0.46, p = 0.002), RV/TLC (B = 0.61, p = 0.015), and PC₂₀ (B = -9.3, p = 0.024). Current smoking and FEV₁ were not significantly associated with health status in the multiple regression analysis.

Conclusion

We conclude that worse health status in COPD patients is associated with higher inflammatory cell counts in induced sputum. Our findings suggest that airway inflammation and hyperinflation independently contribute to impaired health status in COPD. This may provide a rationale for anti-inflammatory therapy in this disease.

How viral infections cause exacerbation of airway diseases

Exacerbations of asthma and COPD are major causes of morbidity, mortality, and health-care costs. Over the last decade, studies using new molecular diagnostic techniques have established that respiratory viruses are a major cause of exacerbations of both asthma and COPD. The most prevalent viruses detected during exacerbations are the rhinoviruses. Despite the burden of disease associated with exacerbations, little is known about the mechanisms of virus-induced exacerbations of airway diseases. Exacerbations are associated with increased airway inflammation in patients with both asthma and COPD, but many questions remain unanswered regarding the key inflammatory cells and mediators involved. Identifying the key inflammatory mediators involved in exacerbations holds the promise of developing diagnostic and prognostic markers of exacerbation. In addition, such studies can identify new therapeutic targets for the development of novel drugs for the prevention and treatment of exacerbations.

A single nucleotide polymorphism in the CCL1 gene predicts acute exacerbations in chronic obstructive pulmonary disease

RATIONALE

Acute exacerbations (AEs) in chronic obstructive pulmonary disease (COPD) are a major cause of morbidity and mortality in COPD.

OBJECTIVES

The marked heterogeneity in the host defense mechanisms may be attributed to single nucleotide polymorphisms (SNPs) in the inflammatory chemokines that show enhanced expression in the airway of patients with COPD who experience AEs.

METHODS

We investigated four SNPs of the CCL11, CCL1, and CCL5 genes in relation to the frequency and severity of AEs in retrospective and prospective studies of a cohort of 276 male patients with COPD.

MEASUREMENTS AND MAIN RESULTS

In the 2-yr retrospective study , one SNP (National Center for Biotechnology Information SNP reference: rs2282691) in the predicted enhancer region of the CCL1 gene, encoding a chemotactic factor for a series of leukocytes, was significantly associated with the frequency of AEs in a dominant model (Fisher's exact test: odds ratio [OR], 2.70; 95% confidence interval [CI], 1.36-5.36; p=0.004; logistic regression: OR, 3.06; 95% CI, 1.46-6.41; p=0.003; and Kruskal-Wallis test: p=0.003). In the 30-mo prospective study, the "A" allele was a significant risk allele for the severity of AEs, with a gene-dosage effect (Kaplan-Meier method with log-rank test: AA vs. TT; log-rank statistic: 7.67, p=0.006; Cox proportional hazards regression method: OR, 5.93; 95% CI, 1.28-27.48; p=0.023). The electromobility shift assay showed that C/EBPbeta, a key transcriptional factor in response to pulmonary infections, binds to the "T" allele, but not to the "A" allele.

CONCLUSIONS

Variants in the CCL1 gene are associated with susceptibility to AEs through their potential implication in the host defense mechanisms against AEs.

Use of plasma biomarkers at exacerbation of chronic obstructive pulmonary disease

IMPACT

This study explores the use of measuring plasma biomarkers at exacerbation of chronic obstructive pulmonary disease (COPD), providing insight into the underlying pathogenesis of these important events.

RATIONALE

The use of measuring C-reactive protein (CRP) to confirm exacerbation, or to assess exacerbation severity, in COPD is unclear. Furthermore, it is not known whether there may be more useful systemic biomarkers.

OBJECTIVE

To assess the use of plasma biomarkers in confirming exacerbation and predicting exacerbation severity.

METHODS

We assessed 36 biomarkers in 90 paired baseline and exacerbation plasma samples from 90 patients with COPD. The diagnosis of exacerbation fulfilled both health care use and symptom-based criteria. Biomarker concentrations were related to clinical indices of exacerbation severity. Interrelationships between biomarkers were examined to gain information on mechanisms of systemic inflammation at exacerbation of COPD.

MEASUREMENTS AND MAIN RESULTS

To confirm the diagnosis of exacerbation, the most selective biomarker was CRP. However, this was neither sufficiently sensitive nor specific alone (area under the receiver operating characteristic curve [AUC], 0.73; 95% confidence interval, 0.66-0.80). The combination of CRP with any one increased major exacerbation symptom recorded by the patient on that day (dyspnea, sputum volume, or sputum purulence) significantly increased the AUC to 0.88 (95% confidence interval, 0.82-0.93; p<0.0001). There were no significant relationships between biomarker concentrations and clinical indices of exacerbation severity. Interrelationships between biomarkers suggest that the acute-phase response is related, separately, to monocytic and lymphocytic-neutrophilic pathways.

CONCLUSIONS

Plasma CRP concentration, in the presence of a major exacerbation symptom, is useful in the confirmation of COPD exacerbation. Systemic biomarkers were not helpful in predicting exacerbation severity. The acute-phase response at exacerbation was most strongly related to indices of monocyte function.

Novel insights into the aetiology and pathophysiology of increased airway inflammation during COPD exacerbations

Airway inflammation increases during acute exacerbations of COPD. Extrinsic factors, such as airway infections, increased air pollution, and intrinsic factors, such as increased oxidative stress and altered immunity may contribute to this increase. The evidence for this and the potential mechanisms by which various aetiological agents increase inflammation during COPD exacerbations is reviewed. The pathophysiologic consequences of increased airway inflammation during COPD exacerbations are also discussed. This review aims to establish a cause and effect relationship between etiological factors of increased airway inflammation and COPD exacerbations based on recently published data. Although it can be speculated that reducing inflammation may prevent and/or treat COPD exacerbations, the existing anti-inflammatory treatments are modestly effective.

Role of infection and antimicrobial therapy in acute exacerbations of chronic obstructive pulmonary disease

Over the past several years, the significance of acute exacerbations of chronic obstructive pulmonary disease (AECOPD) in patients with chronic airflow obstruction has become increasingly apparent due to the impact these episodes have on the natural history of disease. It is now known that frequent AECOPD can adversely affect a patient's health-related quality of life and short- and long-term pulmonary function. The economic burden of these episodes is also substantial. AECOPDs represent a local and systemic inflammatory response to both infectious and noninfectious stimuli, but the majority of episodes are likely related to bacterial or viral pathogens. Patients with purulent sputum and multiple symptoms are the most likely to benefit from treatment with antibiotics. Antibiotic choice should be tailored to the individual patient, taking into account the severity of the episode and host factors which might increase the likelihood of treatment failure. Current evidence suggests that therapeutic goals not only include resolution of the acute episode, but also prolonging the time to the next event. In the future, preventing exacerbations will likely become increasingly accepted as an additional therapeutic goal in chronic obstructive pulmonary disease patients.