Recovery of an epitope recognized by a novel monoclonal antibody from airway lavage during experimental induction of chronic bronchitis.

Prolonged exposure of dogs to high concentrations of SO2 gas results in a syndrome with many of the characteristics of human chronic bronchitis, including cough and chronic mucous hypersecretion as well as airway obstruction. We developed and used a novel monoclonal antibody, GB-4B, raised against epithelial glycoprotein isolated from human hypersecretory mucus to probe airway lavage samples from dogs before and during prolonged exposure to SO2 gas. There were relatively low mean titers of the epitope recognized by GB-4B in airway lavage fluid as evidenced by enzyme-linked immunosorbent assay before exposure to SO2 gas. After 25 to 50 wk of SO2 exposure, the dogs showed a significant increase in pulmonary resistance and there was a significant increase in the titer of the epitope in the airway lavage fluid. Using the same antibody immunohistochemical analysis of airway tissues from SO2-exposed dogs revealed patchy staining of the mucous glands and airway secretory cells and dense staining along the airway surface; airway tissue from control dogs and one SO2-exposed dog whose lavage fluid did not contain the epitope showed little or no staining. These data demonstrate that similar mucin epitopes appear in airway lavage fluid under hypersecretory conditions in both animals and humans. The epitope may have utility as a marker of chronic mucous hypersecretion.     

Chronic Obstructive Pulmonary Disease： Evidence for an Autoimmune Component

Chronic obstructive pulmonary disease （COPD） is characterized by an irreversible limitation on pulmonary airflow associated with chronic inflammation and mucous hypersecretion （chronic bronchitis） and/or the pathological destruction of alveolar airspaces leading to emphysema. COPD, predominantly as a result of tobacco smoke exposure, represents the fourth leading cause of mortality worldwide and its prevalence is increasing. Despite this, much of the basic mechanisms which contribute to disease progression remain to be elucidated and current therapeutic approaches are, for the most part, based upon alleviating patient symptoms （bronchodilators） as opposed to treating the underlying pathological mechanisms triggered in response to cigarette smoke exposure. The classic disease paradigm suggests that an imbalance of pulmonary matrix proteases versus anti-proteases underlies the tissue destruction and inflammation associated with COPD. However, there is a growing appreciation of the complex and multifaceted nature of the pathological mechanisms associated with disease progression. Recently, there has been mounting evidence indicating that COPD patients exhibit many of the characteristics of a classical autoimmune response. We will discuss current evidence in support of this paradigm and outline how future therapeutic approaches may be tailored to address this.     

Differences in airway remodeling between asthma and chronic obstructive pulmonary disease

The functional consequence of asthma and chronic obstructive pulmonary disease (COPD) is airflow limitation, which is mostly reversible in asthma and not fully reversible in COPD. In both diseases, inflammatory conditions are associated with cellular and structural changes, referred to as remodeling, and these structural changes may lead to thickening of the airway wall, thereby promoting airway narrowing and airflow limitation. However, the pattern of infilatrated cells and the pattern of structural changes occur differently in the two diseases. In asthma, CD4+, T lymphocytes, eosinophils, and mast cells are the predominant cells involved, whereas COPD, CD8+, T lymphocytes, and macrophages are predominantly involved. In severe cases of asthma and COPD, neutrophil infiltration becomes evident. Regarding structural changes, epithelial injury and early thickening of reticular basement membrane are highly characteristic of the airway wall of asthmatics. Increases in airway smooth muscle mass occur in large airways of severe asthmatics and in small airways of patients with COPD. Thickening of the airway wall, golblet cell hyperplasia, mucous gland hypertrophy, and the luminal obstruction caused by inflammatory exudates and mucous are features of both asthma and COPD. Squamous epithelial metaplasia and airway wall fibrosis are commonly observed characteristics of COPD. Destruction and fibrosis of the alveolar wall occur in COPD but not in asthma. The remodeling processes accompanied by chronic inflammatory infiltrates interact in a complex fashion and contribute to the development of airflow limitation in both asthma and COPD.     

核受体在慢性气道炎症性疾病中的作用

慢性气道炎症性疾病以气道炎症反应、气道重塑、黏液高分泌等为主要病理特征。核受体为配体活化的转录因子，可降低气道高反应性，减轻炎性细胞和因子所致的气道炎症，减少黏液分泌等，在慢性气道炎性疾病的发生发展过程中起着重要的作用。核受体可单独或相互联系而发挥作用，亦可与其他转录因子进行交互通话。因此，深入研究核受体及其配体的作用将为慢性气道炎症性疾病展现广阔的治疗前景。     

Role of viral infections in asthma and chronic obstructive pulmonary disease

Substantial evidence implicates common respiratory viral infections in the pathogenesis of asthma and chronic obstructive pulmonary disease (COPD). Children who experience recurrent virally induced wheezing episodes during infancy are at greater risk for developing asthma. In addition, respiratory viral infections are a major trigger for acute exacerbations of both asthma and COPD. Despite the importance of viral infections in asthma and COPD, the mechanisms by which viruses predispose to, or cause exacerbations of, these diseases remain poorly understood. It is clear that viral infections lead to enhanced airway inflammation and can cause airways hyperresponsiveness. The epithelial cell is the principal site of viral infection in the airways and plays a central role in viral modulation of airway inflammation via release of a variety of cytokines, chemokines, and growth factors. The mechanisms by which viral infections modulate epithelial function, therefore, is a topic of intense investigation. The epithelium also contributes to the host innate defense response to viral infection by releasing products that are antiviral and/or can lead to increased recruitment of dendritic cells and lymphocytes. Some evidence supports a role for the epithelial cell in specific immunity, although the response of more conventional cells of the immune system to viral infections is likely the dominant factor in this regard. Although current therapies may help combat virally induced disease exacerbations, they are less than ideal. A better understanding of the mechanisms underlying viral modulation of these diseases, therefore, may lead to new therapeutic approaches.     

Bacterial infection in chronic obstructive pulmonary disease in 2000: a state-of-the-art review

Chronic obstructive pulmonary disease (COPD) is the fourth leading cause of death in the United States. The precise role of bacterial infection in the course and pathogenesis of COPD has been a source of controversy for decades. Chronic bacterial colonization of the lower airways contributes to airway inflammation; more research is needed to test the hypothesis that this bacterial colonization accelerates the progressive decline in lung function seen in COPD (the vicious circle hypothesis). The course of COPD is characterized by intermittent exacerbations of the disease. Studies of samples obtained by bronchoscopy with the protected specimen brush, analysis of the human immune response with appropriate immunoassays, and antibiotic trials reveal that approximately half of exacerbations are caused by bacteria. Nontypeable Haemophilus influenzae, Moraxella catarrhalis, and Streptococcus pneumoniae are the most common causes of exacerbations, while Chlamydia pneumoniae causes a small proportion. The role of Haemophilus parainfluenzae and gram-negative bacilli remains to be established. Recent progress in studies of the molecular mechanisms of pathogenesis of infection in the human respiratory tract and in vaccine development guided by such studies promises to lead to novel ways to treat and prevent bacterial infections in COPD.     

阿奇霉素对慢性阻塞性肺疾病模型大鼠气道炎症和气道黏液高分泌的影响

目的:研究阿奇霉素对慢性阻塞性肺疾病(简称慢阻肺)模型大鼠的防治作用,从气道炎症及黏液高分泌角度探讨其作用机制。方法:将18只雄性SD大鼠随机分为正常对照组、慢阻肺模型组、阿奇霉素治疗组,每组6只。通过烟熏及大鼠气管内注入脂多糖(LPS)的方法建立慢性阻塞性肺疾病大鼠模型。HE染色观察大鼠肺组织病理变化。肺功能仪检测大鼠肺通气功能。ELISA检测各组大鼠支气管肺泡灌洗液(BALF)中白细胞介素(IL)-8、IL-17和肿瘤坏死因子-α(TNF-α)的含量。Western blot及real-time PCR检测支气管肺组织中MUC5ac和Toll样受体4(TLR4)蛋白及mRNA的表达。结果:模型组大鼠支气管肺组织HE染色结果符合慢阻肺病理改变。与模型组比较,治疗组损伤程度显著减轻。模型组与对照组比较,肺功能明显下降,大鼠BALF中IL-8、IL-17、TNF-α含量明显增高(P0.05),肺组织中MUC5ac和TLR4蛋白及mRNA表达水平显著增高(P0.05)。与模型组比较,治疗组肺功能的下降减轻,大鼠BALF中IL-8、IL-17、TNF-α含量的升高受到明显抑制(P0.05),肺组织中MUC5ac和TLR4蛋白及mRNA表达水平的受到明显抑制(P0.05)。结论:阿奇霉素可降低慢阻肺模型大鼠BALF中IL-8、IL-17和TNF-α水平,抑制肺组织内MUC5ac和TLR4蛋白表达,通过减轻气道炎症及黏液高分泌来达到防治慢阻肺的作用。     

Nontypeable Haemophilus influenzae and chronic obstructive pulmonary disease: a review for clinicians

Chronic Obstructive Pulmonary Disease (COPD) is a leading cause of morbidity and mortality worldwide. In the lower airways of COPD patients, bacterial infection is a common phenomenon and Haemophilus influenzae is the most commonly identified bacteria. Haemophilus influenzae is divided into typeable and nontypeable (NTHi) strains based on the presence or absence of a polysaccharide capsule. While NTHi is a common commensal in the human nasopharynx, it is associated with considerable inflammation when it is present in the lower airways of COPD patients, resulting in morbidity due to worsening symptoms and increased frequency of COPD exacerbations. Treatment of lower airway NTHi infection with antibiotics, though successful in the short term, does not offer long-term protection against reinfection, nor does it change the course of the disease. Hence, there has been much interest in the development of an effective NTHi vaccine. This review will summarize the current literature concerning the role of NTHi infections in COPD patients and the consequences of using prophylactic antibiotics in patients with COPD. There is particular focus on the rationale, findings of clinical studies and possible future directions of NTHi vaccines in patients with COPD.     

Pathogenesis of chronic obstructive pulmonary disease (COPD)

Chronic obstructive pulmonary disease (COPD) could develop following long-term exposure of individuals to cigarette smoke, toxic gases, and particulate matter, resulting in airway flow limitation, pulmonary failure, multiple systemic effects, and, eventually, death. The disease is associated with pulmonary inflammation with its own specific characteristics, and could be exacerbated by multiple factors such as microbial infection. COPD is chronic and progressive in nature, and multiple pulmonary inflammatory cells are detected at different stages of the disease, with a possible network of interactions with parenchymal cells. The pathological changes in the lung of COPD patients are characterized by an excess of extracellular matrix deposition, yet, loss of extracellular matrix in alveoli, increased thickness of airway walls, mucus hypersecretions, and destruction of alveolar septae, resulting in narrowing of airway diameters, reduced functional lung parenchyma, and decreased elastic tethering forces to maintain airway patency. Multiple factors, such as inflammatory cytokines, proteolytic proteinases, and oxidative stress molecules are suspected to be responsible, each at some degree, for these structural changes leading to airway obstruction. Because not everyone exposed to cigarette smoke will develop the disease, it is reasonable to think that multiple risk factors are involved and that COPD could be developed along a variety of pathways. Our current understanding of pulmonary changes associated with COPD, its similarity and differences with asthma, the nature of inflammatory cells associated with the disease, and the capacity of different molecules to induce a variety of these structural alterations are discussed to advance a cellular and molecular look at the pathogenesis of COPD.     

Cystic fibrosis and other respiratory diseases of impaired mucus clearance

Exposed to a diverse array of potentially noxious agents, the respiratory tract is protected by a highly developed innate defense system. Physiologically regulated epithelial ion and water transport coordinated with mucin secretion, beating cilia, and cough results in continuous flow of fluid and mucus over airway surfaces toward the larynx. This cleansing action is the initial and perhaps most quantitatively important innate defense mechanism. Repeated lung infections and eventual respiratory insufficiency characteristic of human cystic fibrosis (CF) and primary ciliary dyskinesia (PCD) illustrate the consequences of impaired mucus clearance. Altered mucus clearance likely contributes to the initiation, progression, and chronicity of other airway diseases characterized by inflammation and mucous secretory cell hyper/metaplasia that afflict millions worldwide, including chronic obstructive pulmonary disease (COPD). This review concisely discusses the pathophysiology of human diseases characterized by genetic defects that impair mucus clearance. It then explores animal models in which components of the mucus clearance system have been disrupted. These models firmly establish the importance of mucus clearance for respiratory health, and will help elucidate disease mechanisms and therapeutic strategies in CF, PCD and COPD.     

Pathobiology of cigarette smoke-induced chronic obstructive pulmonary disease

Chronic obstructive pulmonary diseases (COPD), comprised of pulmonary emphysema, chronic bronchitis, and structural and inflammatory changes of small airways, is a leading cause of morbidity and mortality in the world. A better understanding of the pathobiology of COPD is critical for the developing of novel therapies, as the majority of patients with the disease have little therapeutic options at the present time. The pathobiology of COPD encompasses multiple injurious processes including inflammation (excessive or inappropriate innate and adaptive immunity), cellular apoptosis, altered cellular and molecular alveolar maintenance program, abnormal cell repair, extracellular matrix destruction (protease and anti-protease imbalance), and oxidative stress (oxidant and antioxidant imbalance). These processes are triggered by urban and rural air pollutants and active and/or passive cigarette smoke and modified by cellular senescence and infection. A series of receptor-mediated signal transduction pathways are activated by reactive oxygen species and tobacco components, resulting in impairment of a variety of cell signaling and cytokine networks, subsequently leading to chronic airway responses with mucus production, airway remodeling, and alveolar destruction. The authors provide an updated insight into the molecular and cellular pathobiology of COPD based on human and/or animal data.     

Systematic review of clinical outcomes in chronic obstructive pulmonary disease

Much controversy surrounds the use of beta-agonists in obstructive lung disease. Regular beta2- agonist use in asthma results in tolerance to its effects and an increase in asthma-related deaths. Less is known about clinical outcomes in chronic obstructive pulmonary disease (COPD). This systematic review and meta-analysis evaluates the long-term effect of beta2-agonist use on severe exacerbations requiring hospitalization or trial withdrawal, respiratory deaths, and total mortality in patients with COPD. Results for beta2-agonists are compared with results for anticholinergics and inhaled corticosteroids. Pooled results from randomized controlled trials show that anticholinergics, such as tiotropium and ipratropium, significantly reduce severe exacerbations and respiratory deaths compared with placebo. Conversely, beta2-agonists increase respiratory deaths, probably because of tolerance that develops to their bronchodilator and bronchoprotective effects. Anticholinergics significantly reduce exacerbations and total mortality compared with beta-agonists. The combination of the two bronchodilators is not more effective than anticholinergics alone in improving long-term clinical outcomes. Inhaled corticosteroids significantly reduce severe exacerbations and the decline in lung function over time, without affecting mortality. In conclusion, inhaled anticholinergic bronchodilators and corticosteroids should be used to improve long-term clinical outcomes in patients with COPD. beta-Agonists increase respiratory deaths in COPD, possibly as a result of poorer disease control.     

慢性阻塞性肺疾病频繁急性加重患者的临床特征分析

目的 观察慢性阻塞性肺疾病（COPD）频繁急性加重患者与非频繁急性加重患者临床特征的差异。方法 回顾性纳入2016年1月~2018年12月合肥市第一人民医院呼吸内科住院的274例COPD急性加重患者,根据患者上一年急性加重次数分为频繁组（住院次数≥2次/年）143例和非频繁组（住院次数＜2次/年）131例,比较两组性别、年龄、病程、吸烟量、mMRC评分、共患疾病（高血压、冠心病、糖尿病）、白细胞计数、中性粒细胞百分比、淋巴细胞百分比、嗜酸粒细胞百分比、降钙素原（PCT）、血气指标（pH、PaO2、PaCO2）及血氧饱和度（SpO2）,多因素Logistic回归分析COPD频繁急性加重的危险因素。结果 两组性别、年龄、白细胞计数、淋巴细胞百分比、嗜酸粒细胞百分比、PCT、pH、PaCO2、共患疾病（高血压、冠心病、糖尿病）比较,差异无统计学意义（P＞0.05）;频繁组病程、吸烟量、mMRC评分、中性粒细胞百分比、SpO2、PaO2均高于非频繁组,差异均有统计学意义（P＜0.05）;多因素Logistic回归分析显示,病程、吸烟量、mMRC评分、中性粒细胞百分比是COPD频繁急性加重的独立危险因素。结论 COPD频繁急性加重多病程较长,患者多长期吸烟,临床中应重视病程长、吸烟量大、mMRC评分高、中性粒细胞百分比高的COPD患者,加强对其的监护管理,防止发生COPD频繁急性加重。     

Airway inflammation in chronic obstructive pulmonary disease: comparisons with asthma

Chronic obstructive pulmonary disease (COPD) is a progressive syndrome of expiratory airflow limitation caused by chronic inflammation of the airways and lung parenchyma. The airway inflammatory response in COPD is initiated by smoking in the overwhelming majority of cases, and chronic exposure to cigarette smoke initiates a series of events that causes damage to central airways, peripheral airways, and terminal airspaces, leading to physiologic and clinical abnormalities. Although COPD shares some clinical features with asthma, another prevalent airway inflammatory disease, there are distinct differences in the phenotypic characteristics of airway inflammation between COPD and asthma. The eosinophil is the most prominent inflammatory cell in asthma, with mast cells, lymphocytes, and macrophages playing important but less prominent roles. In COPD the cellular composition of the airway inflammatory infiltrate differs, with neutrophils, macrophages, and lymphocytes assuming prominence and the eosinophil playing a minor role, except in the setting of exacerbations. The contrasting inflammatory phenotypes of asthma and COPD have important implications for clinical and physiologic manifestations of disease, as well as for therapy.     

Pathogenesis of mucous cell metaplasia in a murine asthma model

Increased mucus production in asthma is an important cause of airflow obstruction during severe exacerbations. To better understand the changes in airway epithelium that lead to increased mucus production, ovalbumin-sensitized and -challenged mice were used. The phenotype of the epithelium was dramatically altered, resulting in increased numbers of mucous cells, predominantly in the proximal airways. However, the total numbers of epithelial cells per unit area of basement membrane did not change. A 75% decrease in Clara cells and a 25% decrease in ciliated cells were completely compensated for by an increase in mucous cells. Consequently, by day 22, 70% of the total epithelial cell population in the proximal airways was mucous cells. Electron microscopy illustrated that Clara cells were undergoing metaplasia to mucous cells. Conversely, epithelial proliferation, detected with 5-chloro-2-deoxyuridine immunohistochemistry, was most marked in the distal airways. Using ethidium homodimer cell labeling to evaluate necrosis and terminal dUTP nick-end labeling immunohistochemistry to evaluate apoptosis, this proliferation was accompanied by negligible cell death. In conclusion, epithelial cell death did not appear to be the stimulus driving epithelial proliferation and the increase in mucous cell numbers was primarily a result of Clara cell metaplasia.     

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.     

Mucus Plugs and Small Airway Dysfunction in Asthma,COPD, and Asthma-COPD Overlap

PurposeThere are reports concerning mucus plugs detected on high-resolution computed tomography images and airflow obstruction in asthma and chronic obstructive pulmonary disease (COPD). However, little is known about the associations between mucus plugs and small airway dysfunction (SAD). We evaluated the relationship between mucus plugs and pulmonary function in patients with asthma, COPD, and asthma-COPD overlap (ACO), and investigated the relevance to SAD and type 2 inflammation in a retrospective study.MethodsSubjects included 49 asthmatic, 40 ACO, and 41 COPD patients. ACO was diagnosed based on the Japanese Respiratory Society ACO guidelines. Clinical and laboratory parameters, including blood eosinophil count, serum total IgE levels, fractional exhaled nitric oxide (FeNO), spirometry, and forced oscillation technique (FOT), were compared between patients with and without mucus plugs.ResultsMucus plugs were found in 29 (59%) asthmatic, 25 (65%) ACO, 17 (41%) COPD patients. Patients with mucus plugs had reduced spirometry and larger FOT parameters, especially in COPD patients. Mucus scores correlated positively with IgE in ACO and FeNO in asthmatic patients, but not in COPD patients. Multivariate logistic regression analysis revealed that SAD parameters, including forced vital capacity and resonant frequency, a respiratory reactance parameter, were significantly associated with the presence of mucus plugs in the whole studied population.ConclusionsSAD, rather than large airway dysfunction, was associated with mucus plugs in asthma, ACO, and COPD patients.