Local and systemic inflammation in chronic obstructive pulmonary disease

There is growing evidence for systemic inflammation in chronic obstructive pulmonary disease (COPD). Increased circulating levels of inflammatory cytokines and acute phase proteins occur in stable disease, and COPD exacerbations are notably associated with pulmonary and systemic inflammation. Although the course of inflammation is determined by the balance between pro- and antiinflammatory mediators, in COPD most attention has focused on the former. During exacerbation, however, upregulation of antiinflammatory markers occurs. The main causes of systemic inflammation in COPD remain to be elucidated, although systemic hypoxia is a candidate factor. Although a relationship between lung and systemic inflammation has been suggested, experimental evidence indicates no direct correlations in the regulation of inflammation in the pulmonary and systemic compartments. Longitudinal studies are needed to unravel the role of systemic inflammation in the course of COPD, to analyze the role of acute exacerbations on the chronicity of inflammation, and to evaluate the response of systemic inflammation to different interventions. Emphasis should be placed on the identification of signaling pathways induced and/or altered in skeletal muscle by inflammation, as muscle wasting is a prominent feature of chronic inflammatory disease conditions and contributes significantly to impaired physical functioning and health status in COPD.     

慢性阻塞性肺疾病合并症研究进展

慢性阻塞性肺疾病(chronic obstructive pulmonary disease,COPD)表现为慢性肺部及全身炎症反应,以进行性不完全可逆性气流受限为特征.COPD患者往往合并一种或多种肺外症状(COPD合并症),这可能是COPD慢性炎症反应的伞身表现,也可能与共同的危险因素(如吸烟、年龄等)有关.这些合...     

The potential impact of anaemia of chronic disease in COPD.

Anaemia of chronic disease (ACD), with chronically low levels of circulating haemoglobin, is an immune driven abnormality that occurs in many inflammatory diseases, and also in chronic heart failure. Although chronic obstructive pulmonary disease (COPD) is "traditionally" associated with polycythaemia, the systemic inflammation that is now recognised as a feature of COPD makes it a possible cause of ACD. If present in COPD, anaemia could worsen dyspnoea and limit exercise tolerance. Preliminary evidence suggests that anaemia in COPD patients may be more prevalent than expected, concerning 10-15% of patients suffering from severe forms of the disease. A database study conducted in 2,524 COPD patients being prescribed long-term oxygen therapy has shown that a low haematocrit is a strong predictor of survival in this population, before body mass index, and is associated with more hospitalisations and a longer cumulative duration of hospitalisation. COPD patients with low haemoglobin levels have a poorer prognosis than COPD patients with normal haemoglobin levels in the event of acute gastrointestinal bleeding or after elective aneurysm repair. Raising haemoglobinaemia through transfusion decreases minute ventilation and work of breathing in COPD patients. These preliminary evidences point to the need to study the prevalence of anaemia, and its physiological and clinical impact in chronic obstructive pulmonary disease. When this body of knowledge is available, the question of the putative benefits of raising haemoglobinaemia in chronic obstructive pulmonary disease will have to be addressed.     

Systemic inflammation and comorbidities in chronic obstructive pulmonary disease

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

Muscle dysfunction in chronic obstructive pulmonary disease: update on causes and biological findings

Respiratory and/or limb muscle dysfunction, which are frequently observed in chronic obstructive pulmonary disease (COPD) patients, contribute to their disease prognosis irrespective of the lung function. Muscle dysfunction is caused by the interaction of local and systemic factors. The key deleterious etiologic factors are pulmonary hyperinflation for the respiratory muscles and deconditioning secondary to reduced physical activity for limb muscles. Nonetheless, cigarette smoke, systemic inflammation, nutritional abnormalities, exercise, exacerbations, anabolic insufficiency, drugs and comorbidities also seem to play a relevant role. All these factors modify the phenotype of the muscles, through the induction of several biological phenomena in patients with COPD. While respiratory muscles improve their aerobic phenotype (percentage of oxidative fibers, capillarization, mitochondrial density, enzyme activity in the aerobic pathways, etc.), limb muscles exhibit the opposite phenotype. In addition, both muscle groups show oxidative stress, signs of damage and epigenetic changes. However, fiber atrophy, increased number of inflammatory cells, altered regenerative capacity; signs of apoptosis and autophagy, and an imbalance between protein synthesis and breakdown are rather characteristic features of the limb muscles, mostly in patients with reduced body weight. Despite that significant progress has been achieved in the last decades, full elucidation of the specific roles of the target biological mechanisms involved in COPD muscle dysfunction is still required. Such an achievement will be crucial to adequately tackle with this relevant clinical problem of COPD patients in the near-future.     

COPD and the response of the lung to tobacco smoke exposure

Chronic Obstructive Pulmonary Disease (COPD) is a major cause of death in the western world and increasing in prevalence in developing countries. COPD is characterised by irreversible airflow obstruction, loss of lung tissue, reduced quality of life and high rates of mortality. The major cause of COPD is tobacco smoke. The changes in the innate immune system directed by tobacco smoke exposure lead to a pronounced and chronic inflammation in the lung. This in turn leads to other pathological changes including remodelling and destruction of lung tissue. Tobacco smoke exposure also leads to infection of the lung by bacteria and viruses. These, bacteria, viruses and co-infection are key triggers of acute worsening’s of COPD termed exacerbations. COPD exacerbations are an additional major factor in the morbidity and mortality within COPD and are also the major healthcare costs associated with the disease. Within this review we discuss the response of the immune system to cigarette smoke exposure and inappropriate harmful responses. Successful treatment strategies will need to balance the positive effects of reducing inflammatory aspects of the disease whilst retaining some of the needed immune responses triggered by tobacco smoke exposure.     

Inflammation and infection in exacerbations of chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is a common disorder with symptoms of chronic cough and progressive dyspnea caused by chronic bronchitis or emphysema. Acute exacerbations of COPD contribute to the accelerated decline in lung function characteristic of this disease and are associated with significant cost, morbidity, and mortality for patients. Controversy exists as to whether exacerbations are caused primarily by inflammation, infection, or perhaps a combination of both conditions. Advances in the pathogenesis of COPD have shed light on the role of inflammation in this condition and highlighted the differences in the inflammatory response present in COPD compared with asthma. Infectious agents often are suspected as causing acute exacerbations of COPD, and antibiotics are frequently prescribed empirically to patients. We review the evidence for an inflammatory and infectious etiology for exacerbations of COPD and compare and contrast how each impacts on this disease.     

Systemic manifestations of COPD

COPD is characterized by a poorly reversible airflow limitation resulting from chronic inflammation, mainly due to tobacco exposure. Over the past few years, the understanding of COPD has evolved from it being a disease affecting the lungs to it being a complex, heterogeneous, and generalized disorder in an aging population. Extrapulmonary comorbidities significantly complicate the management and influence the prognosis of patients with COPD. Although certain comorbidities like cardiovascular diseases share some risk factors with COPD, such as cigarette smoking, other frequently observed comorbidities, including musculoskeletal wasting, metabolic syndrome, and depression, cannot be easily attributed to smoking. There is increasing evidence that chronic inflammation is a key factor in COPD and that inflammation might be the common pathway linking these comorbidities and explaining why they typically develop together. Physicians treating patients with COPD need to become aware of these extrapulmonary aspects. Any patient with COPD should be carefully evaluated for comorbidities and the systemic consequences of COPD since they not only influence the prognosis but also have an impact on disease management. The treatment of COPD is no longer focused exclusively on inhaled therapy but is taking on a multidimensional approach, especially because the treatment of the comorbidities might positively affect the course of COPD itself.     

Coexistent chronic obstructive pulmonary disease-heart failure: mechanisms, diagnostic and therapeutic dilemmas

Mortality in chronic obstructive pulmonary disease (COPD) is more often due to cardiac rather than respiratory causes. The coexistence of heart failure (HF) and COPD is frequent but remains under-diagnosed. Both conditions share several similarities including the age of the population affected, a common risk factor in smoking and symptoms of exertional dyspnoea. There is also a strong possibility of COPD promoting atherosclerotic vascular disease through systemic inflammation. Both the conditions are punctuated by episodes of acute exacerbations of symptoms from time to time where differentiation between these two can be especially challenging. Although coexistence of the two is common, more often, only one of the two is diagnosed resulting in under-treatment and unsatisfactory response. Awareness of co-occurrence is essential among both pulmonologists and cardiologists and a high index of suspicion should be maintained. The coexistence of the COPD and HF also poses several challenges in management. Active search for the second disease using clinical examination supplemented with specialised investigations including plasma natriuretic peptides, lung function testing and echocardiography should be carried out followed by appropriate management. Issues such as adverse effects of drugs on cardiac or pulmonary function need to be sorted out by studies in coexistent COPD-HF patients. Caution is advised with use of beta2-agonists in COPD when HF is also present, more so in acute exacerbations. On current evidence, the beneficial effects of selective beta1-blockers should not be denied in stable patients who have coexistent COPD-HF. The prognosis of coexistent COPD and HF is poorer than that in either disease alone. A favourable response in the patient with coexistent COPD and HF depends on proper evaluation of the severity of each of the two and appropriate management with judicious use of medication.     

Chronic obstructive pulmonary disease: the disease and its burden to society

Chronic obstructive pulmonary disease (COPD) is a multicomponent disease with inflammation at its core, and a major cause of morbidity and mortality. It represents a substantial economic and social burden throughout the world. Currently, COPD is the fifth leading cause of death worldwide, and despite advances in management, mortality is expected to increase in the coming decades, in marked contrast to other chronic diseases, such as heart disease and stroke, where there have been considerable decreases in mortality. On a patient level, the burden of COPD to patients and their families and carers is high, both in terms of health-related quality of life and health status. Health care providers and patients often underestimate the substantial morbidity associated with COPD; the condition is also frequently underdiagnosed and undertreated, which further compromises morbidity. Reducing the burden of COPD requires better evaluation and diagnosis, as well as improved management of chronic symptoms. As exacerbations and hospitalizations represent an important driver of the cost and morbidity of COPD, high priority should be given to interventions aimed at delaying the progression of disease, preventing exacerbations, and reducing the risk of comorbidities to alleviate the clinical and economic burden of disease.     

Inflammatory changes, recovery and recurrence at COPD exacerbation.

Chronic obstructive pulmonary disease (COPD) exacerbations are associated with increased airway and systemic inflammation, though relationships between exacerbation recovery, recurrent exacerbation and inflammation have not been previously reported. In the present study, inflammatory changes at COPD exacerbations were related to clinical nonrecovery and recurrent exacerbations within 50 days. Serum interleukin (IL)-6, C-reactive protein (CRP), sputum IL-6 and IL-8 were measured in 73 COPD patients when stable, at exacerbation and at 7, 14 and 35 days post-exacerbation. In 23% of patients, symptoms did not recover to baseline by day 35. These patients had persistently higher levels of serum CRP during the recovery period. A total of 22% of the patients who had recurrent exacerbations within 50 days had significantly higher levels of serum CRP at day 14, compared with those without recurrences: 8.8 mg.L(-1) versus 3.4 mg.L(-1). Frequent exacerbators had a smaller reduction in systemic inflammation between exacerbation onset and day 35 compared with infrequent exacerbators. Nonrecovery of symptoms at chronic obstructive pulmonary disease exacerbation is associated with persistently heightened systemic inflammation. The time course of systemic inflammation following exacerbation is different between frequent and infrequent exacerbators. A high serum C-reactive protein concentration 14 days after an index exacerbation may be used as a predictor of recurrent exacerbations within 50 days.     

慢性阻塞性肺疾病与慢性炎症

慢性阻塞性肺疾病(chronic obstructive pulmonary disease,COPD)患病率高、病程长、病死率高,已成为严重的社会负担.小气道炎症是COPD的主要病变及导致肺功能进行性损害的主要原因,同时大量研究证明COPD患者存在系统性炎症,但目前对于COPD气道炎症与系统性炎症的关系尚不十分明确.     

无创正压通气在慢性阻塞性肺疾病稳定期中的应用

目前应用于慢性阻塞性肺疾病（COPD）稳定期治疗的方法尚有一定的不足之处或存在一定的局限性。近年来无创正压通气已被广泛应用于COPD急性加重期的治疗,其疗效较为肯定,但是否适用于COPD稳定期的治疗尚未达成一致的共识。本文就无创正压通气在COPD稳定期特别是存在夜间低通气、呼吸肌疲劳或合并阻塞性睡眠呼吸暂停综合征患者中的应用研究进展作一综述。     

Mortality in COPD: Role of comorbidities.

Chronic obstructive pulmonary disease (COPD) represents an increasing burden throughout the world. COPD-related mortality is probably underestimated because of the difficulties associated with identifying the precise cause of death. Respiratory failure is considered the major cause of death in advanced COPD. Comorbidities such as cardiovascular disease and lung cancer are also major causes and, in mild-to-moderate COPD, are the leading causes of mortality. The links between COPD and these conditions are not fully understood. However, a link through the inflammation pathway has been suggested, as persistent low-grade pulmonary and systemic inflammation, both known risk factors for cardiovascular disease and cancer, are present in COPD independent of cigarette smoking. Lung-specific measurements, such as forced expiratory volume in one second (FEV(1)), predict mortality in COPD and in the general population. However, composite tools, such as health-status measurements (e.g. St George's Respiratory Questionnaire) and the BODE index, which incorporates Body mass index, lung function (airflow Obstruction), Dyspnoea and Exercise capacity, predict mortality better than FEV(1) alone. These multidimensional tools may be more valuable because, unlike predictive approaches based on single parameters, they can reflect the range of comorbidities and the complexity of underlying mechanisms associated with COPD. The current paper reviews the role of comorbidities in chronic obstructive pulmonary disease mortality, the putative underlying pathogenic link between chronic obstructive pulmonary disease and comorbid conditions (i.e. inflammation), and the tools used to predict chronic obstructive pulmonary disease mortality.     

COPD患者糖皮质激素不敏感的发生机制和应对策略研究进展

COPD 是常见的慢性气道炎症性疾病,持续气道炎症导致不完全可逆的气流受限和肺结构破坏,引起肺功能进行性下降。尽管目前 COPD 的诊断和治疗已有很大的进步,但由于大气污染加重、烟雾和臭氧暴露增加, COPD 的发病率和病死率在全球仍居高不下。糖皮质激素(glucocorticoid,GC)在哮喘等常见慢性炎症疾病和自身免疫性疾病中的治疗有效性已被临床实践证实,但大量实验研究表明,GC 在 COPD 治疗中疗效欠佳,出现 GC 不敏感现象,因此关于 COPD 患者 GC 不敏感的机制和对策研究意义重大。本文就 COPD 患者气道炎症特征、GC 不敏感发生机制、改善 GC 不敏感的应对策略进行综述。     

Link between chronic obstructive pulmonary disease and coronary artery disease: implication for clinical practice

Chronic obstructive pulmonary disease (COPD) and coronary artery disease (CAD) are global epidemics that incur significant morbidity and mortality. These diseases are frequently found in combination, and they can also be found independent of the common causal factors, primarily smoking. Both conditions are systemic disorders with overlapping mechanisms and pathophysiologic processes. CAD has a strong effect on the severity and prognosis of COPD and vice versa, including acute exacerbations. Even the most recent practical clinical recommendations driven by Clinical Practice Guidelines still focus on one disease at a time, and do not provide advice for the management of patients with associated chronic conditions. COPD should be approached in a more comprehensive manner, including the treatment of cardiac comorbidities, particularly CAD. To focus treatment on these comorbidities might modify the natural course of the disease in patients with COPD who may not find relief from treatment of COPD alone.     

Clinical determinants of exacerbations in severe, early-onset COPD.

Chronic obstructive pulmonary disease (COPD) exacerbations impair health. The present authors analysed participants in the Boston Early-Onset COPD Study for familial aggregation and propensity for COPD exacerbations. In the present study, two exacerbation outcomes, episodes of cough and phlegm, and frequent exacerbations were analysed with multivariable modelling and generalised estimating equations. In early-onset COPD probands, passive tobacco smoke exposure within the home was strongly associated with episodes of cough and phlegm. Chronic phlegm production was associated with both exacerbation phenotypes in probands. In first-degree relatives of early-onset COPD probands, chronic bronchitis, episodic wheezing, pneumonia and active smoking were associated with the episodes of cough and phlegm phenotype. In relatives, identical characteristics plus exertional dyspnoea were associated with frequent exacerbations. Exacerbation risk increased with declining lung function. Familial aggregation for episodes of cough and phlegm was observed in relatives with severe obstruction. In conclusion, passive smoke exposure increases morbidity in severe early-onset chronic obstructive pulmonary disease probands, and chronic obstructive pulmonary disease exacerbations correlate with chronic sputum production in probands and relatives. The familial aggregation of exacerbations suggests a genetic basis for susceptibility to chronic obstructive pulmonary disease exacerbations.     

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

RATIONALE: In addition to pulmonary involvement, stable chronic obstructive pulmonary disease (COPD) is associated with nasal and systemic inflammation. Although exacerbations of COPD are associated with increased pulmonary and systemic inflammation, determinants of the systemic response remain obscure, and nor is it known whether there is nasal involvement. OBJECTIVES: To investigate upper airway, lower airway, and systemic inflammation at exacerbation of COPD. METHODS: We sampled sputum, nasal wash, and serum from 41 exacerbations (East London cohort) for analysis of pathogenic microorganisms and inflammatory indices (sputum/nasal wash leukocytes, interleukin [IL]-6, IL-8, and myeloperoxidase; serum IL-6 and C-reactive protein). Values were compared with stable COPD. MEASUREMENTS AND MAIN RESULTS: Exacerbation of COPD is associated with greater nasal, sputum, and serum inflammation than the stable state. At exacerbation, inflammatory markers were highly correlated within nasal wash and serum (all r >/= 0.62, p < 0.001), but not sputum. The degree of upper airway inflammation correlated with the degree of lower airway inflammation (e.g., nasal wash/sputum myeloperoxidase; r = 0.50, p = 0.001). The degree of systemic inflammation correlated with the degree of lower airway inflammation (e.g., serum IL-6/sputum IL-8; r = 0.35, p = 0.026), and was greater in the presence of a sputum bacterial pathogen (29.0 g/dl C-reactive protein difference, p = 0.002). We did not find relationships between the upper airway and systemic compartments. CONCLUSIONS: Exacerbation of COPD is associated with pan-airway inflammation; the systemic inflammatory response is proportional to that occurring in the lower airway and greater in the presence of a bacterial pathogen.     

Effects of corticosteroids on systemic inflammation in chronic obstructive pulmonary disease

Patients with chronic obstructive pulmonary disease (COPD) are predisposed to atherosclerosis and coronary artery disease, but the underlying mechanisms are unclear. Although there is wide acceptance that atherosclerosis is related to systemic inflammation, the cause(s) and mechanism(s) of pulmonary inflammation in stable COPD remain unknown. Infectious (bacterial and viral) as well as noninfectious agents can cause acute exacerbations in COPD, and they intensify local and systemic inflammation. Although it is not known how systemic inflammation develops in stable COPD, there is good evidence to suggest that it occurs and that the intensity of systemic inflammation is linked to the severity of airflow obstruction. We postulate that systemic inflammation provides the linkage between COPD and atherosclerosis. Inhaled corticosteroids have been shown to improve health outcomes in COPD, but the mechanism by which this occurs is a pivotal and challenging question that has yet to be answered. To prove the concept that inhaled corticosteroids could suppress systemic inflammation (as exemplified by serum C-reactive protein [CRP] levels), a double-blind, placebo-controlled clinical trial was conducted in a group of patients with mild to moderate COPD. We found that withdrawal of inhaled corticosteroids increased serum CRP levels, and that reintroduction of inhaled fluticasone could suppress CRP levels.     

Comorbidities in COPD: a new challenge in clinical practice

Today it is a recognised fact that chronic obstructive pulmonary disease (COPD) is a real systemic disease that is respiratory-based. Recently, the focus has been on the importance of the comorbidities that are associated with COPD, such as all the cardiovascular diseases, lung cancer, diabetes, metabolic syndrome, peripheral muscular dysfunction, depression, anxiety, osteoporosis and anaemia, etc. These comorbidities constitute a new medical and therapeutic challenge with regard to COPD; their high frequency and considerable impact on the quality of life and the prognosis for survival of the patients make them a key element. The aims of this focus are to present the spectrum and prevalence of comorbidities in COPD, to obtain an objective view as to why and how these comorbidities should be systematically assessed and treated in patients, and subsequently to discuss the impact of this new data in clinical practice and in research. This recent data is another positive step in understanding the disease, optimising the diagnosis, and assessing and caring for COPD patients.