慢性阻塞性肺疾病呼出气冷凝液中生物标记物的研究进展

呼出气冷凝液(exhaled breath condensate,EBC)检测作为一种新的研究肺部疾病的方法,具有无创、简便易行、实时监测、重复性好、患者易耐受等优点.对慢性阻塞性肺疾病(chronic obstructive pulmonary disease,COPD)患者EBC中反映气道炎症、氧化应激状态的生物标...     

呼出气冷凝液在慢性阻塞性肺疾病中的研究进展

呼出气冷凝液(exhaled breath condensate,EBC)检测作为一种新的研究肺部疾病的方法,具有无创、简便易行、实时监测、重复性好、患者易耐受等优点.对COPD患者EBC中反映气道炎症、氧化应激状态的生物标记物进行研究有助于COPD的诊断及对药物治疗反应的评估和患者预后的评价.而且EBC中异常炎症介质的研究可能为COPD发病机制开启新思路并发现新的治疗靶点.     

Exhaled metallic elements and serum pneumoproteins in asymptomatic smokers and patients with COPD or asthma

STUDY OBJECTIVES: The aim of this study was to characterize the elemental composition of exhaled breath condensate (EBC) in order to identify new biomarkers of exposure and susceptibility in COPD patients. Serum pneumoproteins were used as lung-specific biomarkers of effect. DESIGN: EBC was obtained from 50 healthy subjects, 30 healthy smokers, 30 asthmatics, and 50 patients with stable COPD, and was collected by cooling exhaled air. Trace elements and toxic metals in the samples were measured by means of inductively coupled plasma-mass spectrometry and electrothermal atomic absorption spectroscopy. The serum pneumoproteins were immunoassayed. RESULTS: The EBC of COPD subjects had higher levels of such toxic elements as lead, cadmium, and aluminum, and lower levels of iron and copper, than that of the nonsmoking control subjects. There were no between-group differences in surfactant protein (SP)-A and SP-B levels. Clara-cell protein and SP-D levels were negatively and positively influenced, respectively, by tobacco smoke. CONCLUSIONS: Our results show that toxic metals and transition elements are detectable in the EBC of studied subjects. We propose new biomarkers of exposure as a means of assessing the target tissue dose of carcinogenic and pneumotoxic substances from tobacco smoke or polluted workplaces, and the use of the transition elements involved in redox systems of oxidative stress as disease biomarkers associated with effect or susceptibility. Together with biomarkers of effect, such as serum pneumoproteins, the elemental composition of EBC may be clinically useful in distinguishing similar diseases.     

慢性阻塞性肺疾病患者呼出气冷凝液中髓过氧化物酶的检测及其意义

目的 检测COPD患者呼出气冷凝液（EBC）中髓过氧化物酶（MPO）浓度,探讨MPO与COPD发病发展的关系.方法 纳入49例COPD患者、18例健康体检者作为研究对象,采用EcoscrecnEBC收集仪采集标本,以酶免疫法测定EBC中MPO浓度.结果 COPD组EBC中MPO浓度显著高于健康对照组[（35.68±0.32）μg/L vs （11.72±0.34）μg/L,P＜0.05];COPD组EBC中MPO浓度与患者FEV1％ pred、呼气流量峰值呈正相关（相关系数r分别为0.418、0.327,P值均＜0.05）.结论 EBC中的MPO浓度能监测肺组织局部的炎症和氧化应激程度,能反映COPD患者病情严重程度,有助于发现COPD的病情变化,是一种较好的评价COPD病情的生物学指标.     

Non-invasive assessment of exhaled biomarkers in lung transplantation

Biomarkers in exhaled breath condensate (EBC) and fractional exhaled nitric oxide (FeNO) have been widely evaluated in respiratory research as non-invasive methods of sampling the lungs. These methods are particularly attractive in lung transplantation (LTx) as they are simple, repeatable and sensitive. Chronic rejection, manifest by progressive airflow limitation and bronchiolitis obliterans syndrome (BOS), is currently the major limiting factor to long-term survival in LTx. Early detection of BOS and initiation of appropriate treatment could significantly improve survival. Exhaled breath biomarkers could allow early diagnosis of factors associated with chronic rejection. FeNO is elevated in LTx patients with infections and chronic rejection prior to clinical presentation, and several EBC biomarkers and volatile organic compound patterns also show promise in these areas. This review summarizes information on exhaled breath biomarkers in LTx and discusses their potential role in the management of LTx patients.     

慢性阻塞性肺疾病急性加重期呼出气冷凝液中的标记物及其意义

慢性阻塞性肺疾病（COPD）急性加重期存在着炎症反应和氧化应激反应,这些变化可通过对呼出气冷凝液中生物学标记物的检测得知。呼出气冷凝液是一种可重复的无创检测手段,目前可用于检测的主要标记物有过氧化氢、花生四烯酸衍生物、脂质过氧化产物、一氧化氮衍生物及细胞因子等。本文主要介绍上述各标记物在COPD急性加重期的临床意义。     

Breath condensate nitrite correlates with hyperinflation in chronic obstructive pulmonary disease

Estimating the degree of pulmonary hyperinflation in chronic obstructive pulmonary disease (COPD) is not always straight forward. Standard pulmonary function tests provide only a crude estimate of this important aspect of COPD. In addition, good patient cooperation cannot always be achieved and therefore adds to the uncertainties with regard to the extent of hyperinflation of the lung. The aim of this investigation was to characterize exhaled breath condensate nitrite in volunteers, healthy smokers, and stable COPD (GOLD-stages 0-4) and to compare this parameter with inflammatory markers in exhaled breath condensate and with lung function in order to test the hypothesis that elevated exhaled breath condensate nitrite reflects hyperinflation in COPD. We found a logarithmic correlation of exhaled breath condensate nitrite to residual volume (r=0.75, p<0.0001), total lung capacity (r=0.51, p<0.0001), and thoracic gas volume (r=0.71, p<0.0001) but no correlation of exhaled breath condensate nitrite concentrations with levels of inflammatory cytokines in exhaled breath condensate (interleukin (IL)-8, IL-1beta, IL-6, IL-10, IL-12, and tumor necrosis factor-alpha). Analysis of COPD subgroups revealed a logarithmic correlation of EBC nitrite to residual volume, total lung capacity, and intrathoracic gas volume exclusively for patients characterized by GOLD classes 2, and higher. Our results confirm a relation of exhaled breath condensate nitrite levels and hyperinflation measured by conventional pulmonary function tests. Investigations using isolated lung models and cells stretched in culture also provide insight into this relation. Exhaled breath condensate nitrite may be a biochemical indicator of pulmonary overdistension.     

Effects of corticosteroids on noninvasive biomarkers of inflammation in asthma and chronic obstructive pulmonary disease

Exhaled breath analysis may be used to quantify inflammation and oxidative stress in the respiratory tract, in the differential diagnosis of airway diseases, and in the monitoring of therapy. The greatest progress has been made with standardized measurement of exhaled nitric oxide (NO). Bronchial NO is increased in asthma, correlated with other markers of inflammation, and reduced by treatment with corticosteroids and antileukotrienes. Alveolar NO is increased in chronic obstructive pulmonary disease (COPD), reflecting disease severity and progression. Exhaled carbon monoxide and ethane are increased in both asthma and COPD. Increased concentrations of 8-isoprostane, hydrogen peroxide, nitrite, and nitrotyrosine are found in exhaled breath condensate from patients with inflammatory lung diseases. Increased levels of lipid mediators are also found, and the pattern depends on the nature of the disease process. Additional biomarkers are exhaled breath temperature, which is elevated in asthma and reduced in COPD, and bronchial blood flow. It is likely that smaller and more sensitive analyzers will extend the discriminatory value of exhaled breath analysis and that new techniques will become available to diagnose and monitor respiratory diseases in the family practice and home settings.     

Exhaled breath condensate in pulmonary arterial hypertension

Over the last decade, several new agents have been developed for the treatment of pulmonary arterial hypertension (PAH), and blood biomarkers have been developed which aim to monitor such treatment, and which correlate well with physiological parameters, symptoms and mortality. However, little is known regarding biomarkers collected using non-invasive methods such as exhaled breath condensate (EBC). EBC biomarkers show potential as a rapid, repeatable and easy method of sampling the pulmonary vasculature in severely ill patients. The current study aimed to investigate EBC biomarkers in patients with PAH of different aetiologies. We studied 89 patients in four groups: pulmonary arterial hypertension (PAH, n = 30), PAH associated with COPD (COPD/PAH, n = 14), COPD but no PAH (n = 16) and healthy controls (n = 29). Levels of the following EBC markers were measured: amino-terminal pro-brain natriuretic peptide (NT-proBNP), endothelin-1 (ET-1), 6-keto prostaglandin (PG)F(1α), hydrogen peroxide (H(2)O(2)), total oxides of nitrogen (NO(x)), total protein and pH. ET-1 and NT-proBNP were measured in plasma concurrently. Data were analysed with ANOVA or Kruskal Wallis tests where appropriate. Correlations were performed using Pearson's correlation coefficient. NT-proBNP was detectable in EBC and was highest in the PAH group, significantly higher than the COPD/PAH group (194.1 ± 23.3 versus 80.8 ± 22.2 fmol ml(-1), p < 0.05). EBC ET-1 was significantly higher in subjects with PAH (1.53 ± 0.32 fmol ml(-1)) compared to those with COPD/PAH (0.25 ± 0.03 fmol ml(-1), p < 0.05) and controls (0.66 ± 0.18 fmol ml(-1), p < 0.05). 6-keto PGF(1α) was low in the PAH group, significantly lower than the COPD/PAH group (4027 ± 445 versus 8381 ± 1024 pg ml(-1), p < 0.01). EBC biomarkers are measurable in PAH. EBC ET-1 was raised in PAH compared with controls and patients with PAH secondary to COPD, whereas 6-keto PGF(1α) was low. EBC biomarkers may be useful in detection and monitoring of PAH.     

慢性阻塞性肺疾病呼出气冷凝液中的生物标记物及其意义

呼出气冷凝液(exhaled breath condensate,EBC)是一种无创研究气道内衬液成分的方法,也为评估肺部炎症提供可能.目前普遍认为,慢性阻塞性肺疾病(chronic obstructive pulmonary disease,COPD)是以气道、肺实质和肺血管的慢性炎症为特征的疾病.通过对COPD患者EBC的收集和检测,可实现对气道炎症的实时、无创、简单、重复的监测.     

Exhaled breath condensate analysis in chronic obstructive pulmonary disease

The increasing focus on airway inflammation in the pathogenesis of chronic obstructive pulmonary disease (COPD) has led to development and evolution of tools to measure it. Direct assessment of airway inflammation requires invasive procedures, and hence, has obvious limitations. Non-invasive methods to sample airway secretions and fluids offer exciting prospects. Analysis of exhaled breath condensate (EBC) is rapidly emerging as a novel non-invasive approach for sampling airway epithelial lining fluid and offers a convenient tool to provide biomarkers of inflammation. It has definite advantages that make it an attractive and a feasible option. It is a source of mediators and molecules that are the causes or consequences of the inflammatory process. Measurement of such markers is increasingly being explored for studying airway inflammation qualitatively and quantitatively in research studies and for potential clinical applications. These biomarkers also have the potential to develop into powerful research tools in COPD for identifying various pathways of pathogenesis of COPD that may ultimately provide specific targets for therapeutic intervention. The EBC analysis is still an evolving noninvasive method for monitoring of inflammation and oxidative stress in the airways. The limited number of studies available on EBC analysis in COPD have provided useful information although definite clinical uses are yet to be defined. Evolving technologies of genomics, proteomics, and metabonomics may provide deeper and newer insights into the molecular mechanisms underlying the pathogenesis of COPD.     

慢性阻塞性肺疾病呼出气冷凝液中的生物标记物及其意义

呼出气冷凝液(exhaled breath condensate,EBC)是一种无创研究气道内衬液成分的方法,也为评估肺部炎症提供可能.目前普遍认为,慢性阻塞性肺疾病(chronic obstructive pulmonary disease,COPD)是以气道、肺实质和肺血管的慢性炎症为特征的疾病.通过对COPD患者EBC的收集和检测,可实现对气道炎症的实时、无创、简单、重复的监测.     

慢性阻塞性肺疾病急性加重期生物标志物的研究进展

C O PD是患病率和病死率居高不下的常见病、多发病,严重影响患者的劳动力和生活质量,也造成了巨大的社会、经济负担。而COPD急性加重（AECOPD）不仅加速疾病进展、进一步降低患者活动耐量,更增加了住院率及病死率,因而近年来开展了大量围绕 A EC O PD生物标志物的研究。本文将从外周血、痰液（包括诱导痰）、呼出气、呼出气冷凝液、BALF、支气管黏膜活检这6个方面分类对近年来A EC O PD生物标志物的研究进展作一综述。     

Reproducibility of exhaled breath condensate pH in chronic obstructive pulmonary disease.

Increasingly, exhaled breath condensate (EBC) is being used to sample airway fluid from the lower respiratory tract. EBC pH may be a biomarker of airway inflammation in chronic obstructive pulmonary disease (COPD). In this study, the reproducibility of EBC pH in COPD was investigated. A total of 36 COPD patients and 12 healthy nonsmoking subjects participated in several investigations: duration of argon deaeration, within-sample variability, effect of freezing, leaving samples at room temperature, nose-peg use, within- (WD) and between-day (BD) variability. Analysis of repeated measurements was performed using the Bland-Altman method with limits of agreement (LOA; mean difference+/-2 SD). Wider LOA indicate greater variability. EBC pH became significantly higher with argon deaeration for < or =5 min. Variability during sample analysis was minimal; LOA of within-sample variability, freezing for 3 months and leaving at room temperature for 3 h were -0.29-0.45, -0.37-0.42 and -0.13-0.09, respectively. In contrast, variability due to nose-peg use (LOA -1.46-1.99), WD (LOA -1.50-2.48) and BD variability (LOA -2.52-3.02) were higher in COPD. In healthy nonsmoking subjects, nose-peg use (LOA -0.27-0.23), WD (LOA -0.33-0.40) and BD variability (LOA -0.46-0.44) were more reproducible. In conclusion, the variability of exhaled breath condensate pH in chronic obstructive pulmonary disease patients is mainly due to changes in airway pH over time, which are not seen in healthy nonsmoking subjects. Reasons for these fluctuations in exhaled breath condensate pH are unclear and require further investigation.     

Exhaled biomarkers

Assessing airway and lung inflammation is important for investigating the underlying mechanisms of asthma and COPD. Yet these cannot be measured directly in clinical research and practice because of the difficulties in monitoring inflammation. Noninvasive monitoring may assist in early recognition of asthma and COPD, assessment of its severity, and response to treatment, especially during disease exacerbations. There is increasing evidence that breath analysis may have an important place in clinical management of asthma and COPD. The article reviews the role of current noninvasive measurements of exhaled gases, such as nitric oxide (NO), inflammatory markers in exhaled breath condensate (EBC), and exhaled breath temperature, as well as novel methods in monitoring and management of asthma and COPD.     

COPD患者呼出气冷凝液中8-异前列腺素的检测及其意义

目的研究COPD患者呼出气冷凝液（EBC）中8-异前列腺素（8-isoPG）浓度的改变及临床意义。方法收集COPD患者（39例）急性发作期和缓解期以及正常对照组（32例）的EBC,用酶标记法检测EBC中8-isoPG,同时检测AECOPD患者的第一秒呼气容量（FEV1）、最大呼气流速（PEF）、pH值、PaCO2、PaO2及血白细胞总数。结果①COPD患者急性发作期8-isoPG为6.44±3.68 ng/L,高于缓解期（4.04±1.25 ng/L）及正常对照组（3.31±0.91 ng/L）,P〈0.05;②COPD患者8-isoPG浓度与痰量呈正相关,r=0.217,P〈0.05。结论 COPD的急性发作期,8-isoPG升高反映了氧化应激增强。     

Detection of gastro-oesophageal reflux disease (GORD) in patients with obstructive lung disease using exhaled breath profiling

Gastro-oesophageal reflux disease (GORD) has been implicated in the worsening of several respiratory disorders. Current methods of diagnosis lack accuracy, are invasive and can be costly. Recently, novel methods of analysing lung pathophysiology have been developed including the use of an electronic nose and analysis of components of exhaled breath condensate (EBC). We hypothesised that these methods would distinguish patients with GORD from those without GORD in the common obstructive lung diseases and healthy controls. In a cross-sectional study, exhaled breath was analysed using the Cyranose 320 electronic nose, using principal components and canonical discriminant analyses. EBC pH and pepsin were quantified using a pH meter and an enzyme-linked immunosorbent assay, respectively. A standardized reflux disease questionnaire (RDQ) was used to assess reflux symptoms. The Cyranose 320 distinguished exhaled breath profiles of obstructive lung disease patients without GORD from obstructive lung disease patients with GORD (p = 0.023, accuracy 67.6%), asthmatic patients with reflux from asthmatics without GORD (85%, p = < 0.015, interclass M distance > 2.8), but did not produce as robust a profile for patients with COPD and COPD with GORD (p = 0.047, accuracy 64%). Patients with obstructive lung disease and GORD had significantly higher levels of EBC pepsin (9.81 ± interquartile range (IQR) 4.38 ng ml(-1)) than those without GORD (4.6 ± IQR 6.95 ng ml(-1)), as well as healthy controls (3.44 ± IQR 7.87 ng ml(-1); p = < 0.013). EBC pH was not significantly related to the presence of GORD in any group. The RDQ results correlated significantly with the presence of EBC pepsin. This pilot study has shown that exhaled breath profiling can be used for detecting GORD in obstructive lung diseases. While the electronic nose was useful in asthma, EBC pepsin was more helpful in COPD. In this study, several different confounders could potentially have affected results and larger prospective interventional studies are needed.     

Enhanced Exhalation of Matrix Metalloproteinase-9 and Tissue Inhibitor of Metalloproteinase-1 in Patients with COPD Exacerbation: A Prospective Study

Background: Matrix metalloproteinase-9 (MMP-9) and its inhibitor tissue inhibitor of metalloproteinase-1 (TIMP-1) are involved in the pathogenesis of airway inflammation in patients with chronic obstructive pulmonary disease (COPD). However, no study so far has addressed their value as noninvasive biomarkers of airways inflammation. Objective: To evaluate MMP-9 and TIMP-1 concentrations in the exhaled breath condensate (EBC) of patients with stable COPD and also during the exacerbation episode. Methods: EBC and serum samples were collected in 17 stable-phase COPD patients who were current smokers as well as during their first exacerbation episode, and in 22 asymptomatic smokers. EBC and serum levels of MMP-9 and TIMP-1 were measured with ELISA kit. Results: Mean EBC MMP-9 and TIMP-1 levels were higher in patients with stable COPD than in asymptomatic smokers. Exacerbation of COPD increased 2-fold the exhalation of MMP-9 (18.5 ± 10.1 ng/ml vs. 8.9 ± 6.2 ng/ml, p = 0.01) and TIMP-1 (to 41.1 ± 20.4 ng/ml vs. 16.4 ± 6.8 ng/ml, p < 0.001). Both, MMP-9 and TIMP-1 in EBC correlated negatively with FEV(1) (% predicted) at baseline (r = -0.78, p < 0.001 and r = -0.73, p < 0.001) and during the exacerbation episode (r = -0.57, p = 0.02 and r = -0.65, p = 0.005). Similar negative correlations were noted with FVC (% predicted), except for MMP-9 in EBC at exacerbation. Exhaled MMP-9 and TIMP-1 did not correlate with serum concentrations in COPD patients, either at baseline or during exacerbation. Conclusion: Exhaled MMP-9 and TIMP-1 increased during COPD exacerbation and was negatively correlated with spirometric variables, which suggests the usefulness of their measurement in EBC for the monitoring of airways inflammation. However, to better assess their diagnostic or prognostic value larger studies are necessary.     

Proteomics as a Method for Early Detection of Cancer: A Review of Proteomics,Exhaled Breath Condensate,and Lung Cancer Screening

The study of expressed proteins in neoplasia is undergoing a revolution with the advent of proteomic analysis. Unlike genomic studies where individual changes may have no functional significance, protein expression is closely aligned with cellular activity. This perspective will review proteomics as a method of detecting markers of neoplasia with a particular emphasis on lung cancer and the potential to sample the lung by exhaled breath condensate (EBC). EBC collection is a simple, new, and noninvasive technique, which allows sampling of lower respiratory tract fluid. EBC enables the study of a wide variety of biological markers from low molecular weight mediators to macromolecules, such as proteins, in a range of pulmonary diseases. EBC may be applied to the detection of lung cancer where it could be a tool in early diagnosis. This perspective will explore the potential of applying proteomics to the EBC from lung cancer patients as an example of detecting potential biomarkers of disease and progression.     

Proteomics as a method for early detection of cancer: a review of proteomics, exhaled breath condensate, and lung cancer screening

The study of expressed proteins in neoplasia is undergoing a revolution with the advent of proteomic analysis. Unlike genomic studies where individual changes may have no functional significance, protein expression is closely aligned with cellular activity. This perspective will review proteomics as a method of detecting markers of neoplasia with a particular emphasis on lung cancer and the potential to sample the lung by exhaled breath condensate (EBC). EBC collection is a simple, new, and noninvasive technique, which allows sampling of lower respiratory tract fluid. EBC enables the study of a wide variety of biological markers from low molecular weight mediators to macromolecules, such as proteins, in a range of pulmonary diseases. EBC may be applied to the detection of lung cancer where it could be a tool in early diagnosis. This perspective will explore the potential of applying proteomics to the EBC from lung cancer patients as an example of detecting potential biomarkers of disease and progression.