CD8 positive T cells express IL-17 in patients with chronic obstructive pulmonary disease

Background

Chronic obstructive pulmonary disease (COPD) is a progressive and irreversible chronic inflammatory disease of the lung. The nature of the immune reaction in COPD raises the possibility that IL-17 and related cytokines may contribute to this disorder. This study analyzed the expression of IL-17A and IL-17F as well as the phenotype of cells producing them in bronchial biopsies from COPD patients.

Methods

Bronchoscopic biopsies of the airway were obtained from 16 COPD subjects (GOLD stage 1-4) and 15 control subjects. Paraffin sections were used for the investigation of IL-17A and IL-17F expression in the airways by immunohistochemistry, and frozen sections were used for the immunofluorescence double staining of IL-17A or IL-17F paired with CD4 or CD8. In order to confirm the expression of IL-17A and IL-17F at the mRNA level, a quantitative RT-PCR was performed on the total mRNA extracted from entire section or CD8 positive cells selected by laser capture microdissection.

Results

IL-17F immunoreactivity was significantly higher in the bronchial biopsies of COPD patients compared to control subjects (P < 0.0001). In the submucosa, the absolute number of both IL-17A and IL-17F positive cells was higher in COPD patients (P < 0.0001). After adjusting for the total number of cells in the submucosa, we still found that more cells were positive for both IL-17A (P < 0.0001) and IL-17F (P < 0.0001) in COPD patients compared to controls. The mRNA expression of IL-17A and IL-17F in airways of COPD patients was confirmed by RT-PCR. The expression of IL-17A and IL-17F was co-localized with not only CD4 but also CD8, which was further confirmed by RT-PCR on laser capture microdissection selected CD8 positive cells.

Conclusion

These findings support the notion that Th17 cytokines could play important roles in the pathogenesis of COPD, raising the possibility of using this mechanism as the basis for novel therapeutic approaches.     

Genetic susceptibility for chronic bronchitis in chronic obstructive pulmonary disease

Background

Chronic bronchitis (CB) is one of the classic phenotypes of COPD. The aims of our study were to investigate genetic variants associated with COPD subjects with CB relative to smokers with normal spirometry, and to assess for genetic differences between subjects with CB and without CB within the COPD population.

Methods

We analyzed data from current and former smokers from three cohorts: the COPDGene Study; GenKOLS (Bergen, Norway); and the Evaluation of COPD Longitudinally to Identify Predictive Surrogate Endpoints (ECLIPSE). CB was defined as having a cough productive of phlegm on most days for at least 3 consecutive months per year for at least 2 consecutive years. CB COPD cases were defined as having both CB and at least moderate COPD based on spirometry. Our primary analysis used smokers with normal spirometry as controls; secondary analysis was performed using COPD subjects without CB as controls. Genotyping was performed on Illumina platforms; results were summarized using fixed-effect meta-analysis.

Results

For CB COPD relative to smoking controls, we identified a new genome-wide significant locus on chromosome 11p15.5 (rs34391416, OR = 1.93, P = 4.99 × 10^-8) as well as significant associations of known COPD SNPs within FAM13A. In addition, a GWAS of CB relative to those without CB within COPD subjects showed suggestive evidence for association on 1q23.3 (rs114931935, OR = 1.88, P = 4.99 × 10^-7).

Conclusions

We found genome-wide significant associations with CB COPD on 4q22.1 (FAM13A) and 11p15.5 (EFCAB4A, CHID1 and AP2A2), and a locus associated with CB within COPD subjects on 1q23.3 (RPL31P11 and ATF6). This study provides further evidence that genetic variants may contribute to phenotypic heterogeneity of COPD.

Trial registration

ClinicalTrials.gov {"type":"clinical-trial","attrs":{"text":"NCT00608764","term_id":"NCT00608764"}}NCT00608764, {"type":"clinical-trial","attrs":{"text":"NCT00292552","term_id":"NCT00292552"}}NCT00292552

Electronic supplementary material

The online version of this article (doi:10.1186/s12931-014-0113-2) contains supplementary material, which is available to authorized users.     

Compartment differences of inflammatory activity in chronic obstructive pulmonary disease

Background

Chronic obstructive pulmonary disease (COPD) is associated with local and systemic inflammation. The knowledge of interaction and co-variation of the inflammatory responses in different compartments is meagre.

Method

Healthy controls (n = 23), smokers with (n = 28) and without (n = 29) COPD performed spirometry and dental examinations. Saliva, induced sputum, bronchoalveolar lavage (BAL) fluid and serum were collected. Inflammatory markers were assessed in all compartments using ELISA, flow cytometry and RT-PCR.

Results

Negative correlations between lung function and saliva IL-8 and matrix metalloproteinase-9 (MMP-9) were found in smokers with COPD. IL-8 and MMP-9 in saliva correlated positively with periodontal disease as assessed by gingival bleeding in non-smokers.Tumor necrosis factor-α (TNF-α) in saliva, serum and TNF-α mRNA expression on macrophages in BAL-fluid were lower in smokers than in non-smokers. There were positive correlations between soluble TNF-α receptor 1 (sTNFR1) and soluble TNF-α receptor 2 (sTNFR2) in sputum, BAL-fluid and serum in all groups. Sputum interleukin-8 (IL-8) or interleukin-6 (IL-6) was positively correlated with sTNFR1 or sTNFR2 in non-smokers and with sTNFR2 in COPD.

Conclusion

Saliva which is convenient to collect and analyse, may be suitable for biomarker assessment of disease activity in COPD. An attenuated TNF-α expression was demonstrated by both protein and mRNA analyses in different compartments suggesting that TNF-α response is altered in moderate and severe COPD. Shedding of TNFR1 or TNFR2 is similarly regulated irrespective of airflow limitation.     

Nicotinic acetylcholine receptor variants associated with susceptibility to chronic obstructive pulmonary disease: a meta-analysis

Background

Only 10-15% of smokers develop chronic obstructive pulmonary disease (COPD) which indicates genetic susceptibility to the disease. Recent studies suggested an association between COPD and polymorphisms in CHRNA coding subunits of nicotinic acetylcholine receptor. Herein, we performed a meta-analysis to clarify the impact of CHRNA variants on COPD.

Methods

We searched Web of Knowledge and Medline from 1990 through June 2011 for COPD gene studies reporting variants on CHRNA. Pooled odds ratios (ORs) were calculated using the major allele or genotype as reference group.

Results

Among seven reported variants in CHRNA, rs1051730 was finally analyzed with sufficient studies. Totally 3460 COPD and 11437 controls from 7 individual studies were pooled-analyzed. A-allele of rs1051730 was associated with an increased risk of COPD regardless of smoking exposure (pooled OR = 1.26, 95% CI 1.18-1.34, p < 10^-5). At the genotypic level, the ORs gradually increased per A-allele (OR = 1.27 and 1.50 for GA and AA respectively, p < 10^-5). Besides, AA genotype exhibited an association with reduced FEV1% predicted (mean difference 3.51%, 95%CI 0.87-6.16%, p = 0.009) and increased risk of emphysema (OR 1.93, 95%CI 1.29-2.90, p = 0.001).

Conclusions

Our findings suggest that rs1051730 in CHRNA is a susceptibility variant for COPD, in terms of both airway obstruction and parenchyma destruction.     

COPD association and repeatability of blood biomarkers in the ECLIPSE cohort

Background

There is a need for biomarkers to better characterise individuals with COPD and to aid with the development of therapeutic interventions. A panel of putative blood biomarkers was assessed in a subgroup of the Evaluation of COPD Longitudinally to Identify Surrogate Endpoints (ECLIPSE) cohort.

Methods

Thirty-four blood biomarkers were assessed in 201 subjects with COPD, 37 ex-smoker controls with normal lung function and 37 healthy non-smokers selected from the ECLIPSE cohort. Biomarker repeatability was assessed using baseline and 3-month samples. Intergroup comparisons were made using analysis of variance, repeatability was assessed through Bland-Altman plots, and correlations between biomarkers and clinical characteristics were assessed using Spearman correlation coefficients.

Results

Fifteen biomarkers were significantly different in individuals with COPD when compared to former or non-smoker controls. Some biomarkers, including tumor necrosis factor-α and interferon-γ, were measurable in only a minority of subjects whilst others such as C-reactive protein showed wide variability over the 3-month replication period. Fibrinogen was the most repeatable biomarker and exhibited a weak correlation with 6-minute walk distance, exacerbation rate, BODE index and MRC dyspnoea score in COPD subjects. 33% (66/201) of the COPD subjects reported at least 1 exacerbation over the 3 month study with 18% (36/201) reporting the exacerbation within 30 days of the 3-month visit. CRP, fibrinogen interleukin-6 and surfactant protein-D were significantly elevated in those COPD subjects with exacerbations within 30 days of the 3-month visit compared with those individuals that did not exacerbate or whose exacerbations had resolved.

Conclusions

Only a few of the biomarkers assessed may be useful in diagnosis or management of COPD where the diagnosis is based on airflow obstruction (GOLD). Further analysis of more promising biomarkers may reveal utility in subsets of patients. Fibrinogen in particular has emerged as a potentially useful biomarker from this cohort and requires further investigation.

Trial Registration

SCO104960, clinicaltrials.gov identifier {"type":"clinical-trial","attrs":{"text":"NCT00292552","term_id":"NCT00292552"}}NCT00292552     

Specific IgA and metalloproteinase activity in bronchial secretions from stable chronic obstructive pulmonary disease patients colonized by Haemophilus influenzae

Background

Haemophilus influenzae is the most common colonizing bacteria of the bronchial tree in chronic obstructive pulmonary disease (COPD), and positive cultures for this potentially pathogenic microorganism (PPM) has been associated with local inflammation changes that may influence the relationships between H. influenzae and the bronchial mucosa.

Methods

A cross-sectional analysis of stable COPD patients enrolled in the Phenotype and Course of Chronic Obstructive Pulmonary Disease (PAC-COPD) Study, focusing on bronchial colonization by H. influenzae, was performed. Specific IgA against the PPM was measured by optical density, and metalloproteinase-9 (MMP-9) and tissue inhibitor of metalloproteinase-1 (TIMP-1) using ELISA in sputum samples. Levels in patients colonized by H. influenzae and non-colonized patients were compared.

Results

Sputum supernatant for the measurement of specific IgA against H. influenzae was available from 54 stable COPD patients, who showed levels of specific IgA significantly lower in colonized (n=21) than in non-colonized patients (n=33) (15 [4-37] versus 31 [10-75], p=0.033, Mann-Whitney U test). Proenzyme MMP-9 was measured in 44 patients, and it was higher in colonized (n=12, 1903 [1488-6699] ng/ml) than in non-colonized patients (n=32, 639 [373-972] ng/ml) (p<0.001, Mann-Whitney U test). Active form of MMP-9 was also higher in colonized (126 [25-277] ng/ml) than in non-colonized patients (39 [14-68] ng/ml) (p=0.021, Mann-Whitney U test), and the molar ratio between proenzyme MMP-9 and TIMP-1 was above 1 (2.1 [0.1-12.5]) in colonized patients, significantly higher than the ratio found in non-colonized patients (0.2 [0.08-0.5]) (p=0.030, Mann-Whitney U test).

Conclusions

Clinically stable COPD patients colonized by H. influenzae had lower levels of specific IgA against the microorganism and higher values of the active form of MMP-9 in their sputum supernatant than non-colonized patients. Bronchial colonization by H. influenzae may cause structural changes in the extracellular matrix through a defective defense and the production of active metalloproteinases.     

Exhaled volatile organic compounds for phenotyping chronic obstructive pulmonary disease: a cross-sectional study

Background

Non-invasive phenotyping of chronic respiratory diseases would be highly beneficial in the personalised medicine of the future. Volatile organic compounds can be measured in the exhaled breath and may be produced or altered by disease processes. We investigated whether distinct patterns of these compounds were present in chronic obstructive pulmonary disease (COPD) and clinically relevant disease phenotypes.

Methods

Breath samples from 39 COPD subjects and 32 healthy controls were collected and analysed using gas chromatography time-of-flight mass spectrometry. Subjects with COPD also underwent sputum induction. Discriminatory compounds were identified by univariate logistic regression followed by multivariate analysis: 1. principal component analysis; 2. multivariate logistic regression; 3. receiver operating characteristic (ROC) analysis.

Results

Comparing COPD versus healthy controls, principal component analysis clustered the 20 best-discriminating compounds into four components explaining 71% of the variance. Multivariate logistic regression constructed an optimised model using two components with an accuracy of 69%. The model had 85% sensitivity, 50% specificity and ROC area under the curve of 0.74. Analysis of COPD subgroups showed the method could classify COPD subjects with far greater accuracy. Models were constructed which classified subjects with ≥2% sputum eosinophilia with ROC area under the curve of 0.94 and those having frequent exacerbations 0.95. Potential biomarkers correlated to clinical variables were identified in each subgroup.

Conclusion

The exhaled breath volatile organic compound profile discriminated between COPD and healthy controls and identified clinically relevant COPD subgroups. If these findings are validated in prospective cohorts, they may have diagnostic and management value in this disease.     

The unique alterations of hippocampus and cognitive impairment in chronic obstructive pulmonary disease

Background

Cognitive impairment has been found in chronic obstructive pulmonary disease (COPD) patients. However, the structural alteration of the brain and underlying mechanisms are poorly understood.

Methods

Thirty-seven mild-to-moderate COPD patients, forty-eight severe COPD patients, and thirty-one control subjects were recruited for cognitive test and neuroimaging studies. Serum levels of S100B,pulmonary function and arterial blood gas levels were also evaluated in each subject.

Results

The hippocampal volume was significantly smaller in COPD patients compared to the control group. It is positively correlated with a mini mental state examination (MMSE) score, SaO₂ in mild-to-moderate COPD patients, the levels of PaO₂ in both mild-to-moderate and severe COPD patients. Higher S100B concentrations were observed in mild-to-moderate COPD patients, while the highest S100B level was found in severe COPD patients when compared to the control subjects. S100B levels are negatively associated with MMSE in both mild-to-moderate and severe COPD patients and also negatively associated with the hippocampal volume in the total COPD patients.

Conclusions

Hippocampal atrophy based on quantitative assessment by magnetic resonance imaging does occur in COPD patients, which may be associated with cognitive dysfunction and the most prevalent mechanism accountable for hippocampal atrophy is chronic hypoxemia in COPD. Higher serum S100B levels may be peripheral biochemical marker for cognitive impairment in COPD.     

Acute effects of cigarette smoking on inflammation in healthy intermittent smokers

Background

Chronic smoking is the main risk factor for chronic obstructive pulmonary disease. Knowledge on the response to the initial smoke exposures might enhance the understanding of changes due to chronic smoking, since repetitive acute smoke effects may cumulate and lead to irreversible lung damage.

Methods

We investigated acute effects of smoking on inflammation in 16 healthy intermittent smokers in an open randomised cross-over study. We compared effects of smoking of two cigarettes on inflammatory markers in exhaled air, induced sputum, blood and urine at 0, 1, 3, 6, 12, 24, 48, 96 and 192 hours and outcomes without smoking. All sputum and blood parameters were log transformed and analysed using a linear mixed effect model.

Results

Significant findings were: Smoking increased exhaled carbon monoxide between 0 and 1 hour, and induced a greater decrease in blood eosinophils and sputum lymphocytes between 0 and 3 hours compared to non-smoking. Compared to non-smoking, smoking induced a greater interleukin-8 release from stimulated blood cells between 0 and 3 hours, and a greater increase in sputum lymphocytes and neutrophils between 3 and 12 hours.

Conclusion

We conclude that besides an increase in inflammation, as known from chronic smoking, there is also a suppressive effect of smoking two cigarettes on particular inflammatory parameters.     

功率自行车下肢亚极量运动对慢性阻塞性肺疾病康复影响的临床报告*

目的: 研究慢性阻塞性肺疾病（COPD）患者功率自行车下肢亚极量运动的康复治疗效果。方法: 30例门诊COPD患者随机分为康复组和对照组,每组15例,康复前后均完成常规肺功能（PFT）、心肺运动试验（CPET）、血气分析（ABG）、呼吸困难Borg评分和COPD患者自我评估测试问卷（CAT评分）,并比较前后变化。康复组采用功率自行车锻炼,以CPET80%峰值功率强度,每次运动30 min,每周3次,完成12周。结果: 康复组在康复后IC显著提高(P<0.01),peakW和peakVO₂也显著提高(P<0.01);Borg评分和CAT评分显著降低 (P<0.01)。末次运动持续时间较首次明显延长(P<0.01)。而对照组的这些指标均无显著改变(P>0.05)。两组在康复前后的PFT指标和血气分析等参数无明显变化。结论: COPD患者可以安全有效地进行运动康复治疗。功率自行车下肢亚极量运动康复能使COPD患者整体功能改善、运动时间延长、生活质量提高、患者获益。     

Detection of Endogenous Matrix Metalloprotease-12 Active Form with a Novel Broad Spectrum Activity-based Probe

Matrix metalloproteases (MMPs) have attracted considerable attention as critical mediators of pathological tissue remodeling processes. However it remains an unresolved challenge to detect their active forms in biological samples. To prove the efficacy of a recently developed MMP activity-based probe, we examined the content in MMP active forms of bronchoalveolar lavage fluids (BALf) from male C57BL/6 mice exposed to ultrafine carbon black nanoparticles, a model of chronic obstructive pulmonary disease. This probe was shown to label proteins, mostly expressed in BALf of mice exposed to nanoparticles. Using competition assays with a selective MMP-12 inhibitor as well as MMP-12 knock-out mice, one of these proteins was identified as the active form of the catalytic domain of MMP-12. This new probe can detect the active form of MMP-12 down to a threshold of 1 fmol. Radioactive counting showed the concentration of the active form of MMP-12 to be around 1 fmol/μl in BALf from nanoparticle-treated mice. A less sensitive probe would therefore not have detected MMP-12. As the probe can detect other MMPs in the femtomolar range, it is a potentially powerful tool for monitoring the levels of MMP active forms in various diseases.     

幽门螺杆菌在慢性阻塞性肺疾病发生及 发展过程中的作用

目的研究幽门螺杆菌(Helicobacter pylori,H.pylori)在慢性阻塞性肺疾病(COPD)发生及发展过程中的作用。方法对85例COPD患者(COPD组)和85例体检健康者(对照组)进行血清抗H.pylori抗体(抗Hp-IgG)检测,比较两组的抗Hp-IgG水平及H.pylori阳性率。全部COPD患者均行肺功能和免疫功能检查,分析抗Hp-IgG水平与COPD严重程度的相关性,比较合并H.pylori感染与无H.pylori感染COPD患者之间,以及合并H.pylori感染COPD患者根除H.pylori前后免疫功能的差异。结果 COPD组血清抗Hp-IgG水平和H.pylori阳性率均明显高于对照组(P0.05),FEV1%预计值与血清抗Hp-IgG水平呈负相关(P0.05)。与无H.pylori感染的COPD患者相比,合并H.pylori感染的COPD患者外周血CD_3~+和CD_4~+T细胞含量、CD_4~+/CD_8~+比值、血清免疫球蛋白(IgA、IgG、IgM)水平均明显较低(P0.05),经H.pylori根除治疗后各指标水平明显升高(P0.05)。结论 H.pylori感染可导致宿主免疫功能紊乱,可能因此促进了COPD的发生和发展。根除H.pylori可明显改善合并H.pylori感染COPD患者的免疫功能,有利于患者恢复。     

慢性阻塞性肺疾病急性加重期病原菌与其综合评估分级间关系的研究

目的研究慢性阻塞性肺疾病急性加重期（AEC0PD）病原菌分布及耐药情况,与其综合评估分级之间的关系。方法对2008年1月至2012年6月金华市第五医院住院142例AEC0PD患者的痰标本进行细菌培养和药物敏感试验;所有患者按慢性阻塞性肺疾病全球倡仪（GOLD）20U版的要求进行综合评估后分级为A级、B级、C级、D级。结果142例AEC0PD患者有99例患者分离到病原菌,共129株。其中,革兰阴性菌最多,占59.6%,依次为铜绿假单胞菌、肺炎克雷伯菌、鲍曼不动杆菌、大肠埃希菌,体外药敏结果显示大部分革兰阴性菌对亚胺培南有较好敏感性（72% ）;革兰阳性菌占20. 9%,依次为金黄色葡萄球菌、肠球菌、肺炎链球菌,大部分革兰阳性菌对万古霉素有较好敏感性（85% ）;真菌占19. 3% ,分别为A色念珠菌、热带念珠菌等,对氟胞嘧啶、两性霉素、伊曲康唑、伏立康唑等敏感度高。混合感染占总患者的27.2%。A、B、C和D级AEC0PD患者,病原菌为革兰阴性菌的分别占46.6% ,50.0% ,59. 0%和66.0% ;真菌分别为6. 2%、12. 5%、20. 4%和24. 0% ;混合感染患者分别为15. 3%、23.0%、22. 9%和36. 8%。C级、D级患者革兰阴性菌和真菌检出率,混合感染率较A级、B级高（P 〈 0. 05 ）。结论AEC0PD患者病原菌以革兰阴性菌为主,真菌感染、混合感染率亦较髙,病原菌耐药现象严重,患者综合评估分级高。     

阿托伐他汀对慢性阻塞性肺疾病合并肺动脉高压患者外周血ROCK2激酶活性及肺动脉压力的影响

目的：探讨口服阿托伐他汀片对慢性阻塞性肺疾病（chronic obstructive pulmonary Disease,COPD）合并肺动脉高压（pul-monary hypertension,PH）患者外周血ROCK2激酶活性及肺动脉压力的影响。方法：选取COPD合并PH患者60例为研究对象,并将其随机分为对照组（给予吸氧、抗感染、化痰、平喘等基础治疗）和阿托伐他汀治疗组（在基础治疗的基础上给予阿托伐他汀片20mg／d治疗）;随访观察周期12周,于试验开始前和结束后检测外周血ROCK2的活性,利用彩色多普勒检测肺动脉压力的变化,肺功能变化（测定FEV1,FVC）。结果：与对照组比较,阿托伐他汀治疗可显著降低患者血浆中ROCK2的水平（P〈0．01）;降低患者的肺动脉压力,改善患者的肺功能（FEV1,FVC）,P均〈0．05。结论：在常规吸氧、抗感染等治疗的基础上,联合应用阿托伐他汀可显著降低ROCK2激酶的活性和肺动脉压力,从而改善肺功能。     

Analysis of longitudinal changes in dyspnea of patients with chronic obstructive pulmonary disease: an observational study

Background

Guidelines recommend that symptoms as well as lung function should be monitored for the management of patients with chronic obstructive pulmonary disease (COPD). However, limited data are available regarding the longitudinal change in dyspnea, and it remains unknown which of relevant measurements might be used for following dyspnea.

Methods

We previously consecutively recruited 137 male outpatients with moderate to very severe COPD, and followed them every 6 months for 5 years. We then reviewed and reanalyzed the data focusing on the relationships between the change in dyspnea and the changes in other clinical measurements of lung function, exercise tolerance tests and psychological status. Dyspnea with activities of daily living was assessed with the Oxygen Cost Diagram (OCD) and modified Medical Research Council dyspnea scale (mMRC), and two dimensions of disease-specific health status questionnaires of the Chronic Respiratory Disease Questionnaire (CRQ) and the St. George’s Respiratory Questionnaire (SGRQ) were also used. Dyspnea at the end of exercise tolerance tests was measured using the Borg scale.

Results

The mMRC, CRQ dyspnea and SGRQ activity significantly worsened over time (p < 0.001), but the OCD did not (p = 0.097). Multiple regression analyses revealed that the changes in the OCD, mMRC, CRQ dyspnea and SGRQ activity were significantly correlated to changes in forced expiratory volume in one second (FEV₁) (correlation of determination (r²) = 0.05-0.19), diffusing capacity for carbon monoxide (r² = 0.04-0.08) and psychological status evaluated by Hospital Anxiety and Depression Scale (r² = 0.14-0.17), although these correlations were weak. Peak Borg score decreased rather significantly, but was unrelated to changes in clinical measurements.

Conclusion

Dyspnea worsened over time in patients with COPD. However, as different dyspnea measurements showed different evaluative characteristics, it is important to follow dyspnea using appropriate measurements. Progressive dyspnea was related not only to progressive airflow limitation, but also to various factors such as worsening of diffusing capacity or psychological status. Changes in peak dyspnea at the end of exercise may evaluate different aspects from other dyspnea measurements.     

Integrative genomics of chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is a complex disease with both environmental and genetic determinants, the most important of which is cigarette smoking. There is marked heterogeneity in the development of COPD among persons with similar cigarette smoking histories, which is likely partially explained by genetic variation. Genomic approaches such as genomewide association studies and gene expression studies have been used to discover genes and molecular pathways involved in COPD pathogenesis; however, these “first generation” omics studies have limitations. Integrative genomic studies are emerging which can combine genomic datasets to further examine the molecular underpinnings of COPD. Future research in COPD genetics will likely use network-based approaches to integrate multiple genomic data types in order to model the complex molecular interactions involved in COPD pathogenesis. This article reviews the genomic research to date and offers a vision for the future of integrative genomic research in COPD.     

Implication of Interleukin (IL)-18 in the pathogenesis of chronic obstructive pulmonary disease (COPD)

Interleukin (IL)-18 is a pro-inflammatory cytokine that was firstly described as an interferon (IFN)-γ-inducing factor. Similar to IL-1β, IL-18 is synthesized as an inactive precursor requiring processing by caspase-1 into an active cytokine. The platform for activating caspase-1 is known as the inflammasome, a multiple protein complex. Macrophages and dendritic cells are the primary sources for the release of active IL-18, whereas the inactive precursor remains in the intracellular compartment of mesenchymal cells. Finally, the IL-18 precursor is released from dying cells and processed extracellularly.IL-18 has crucial host defense and antitumor activities, and gene therapy to increase IL-18 levels in tissues protects experimental animals from infection and tumor growth and metastasis. Moreover, multiple studies in experimental animal models have shown that IL-18 over-expression results to emphysematous lesions in mice. The published data prompt to the hypothesis that IL-18 induces a broad spectrum of COPD-like inflammatory and remodeling responses in the murine lung and also induces a mixed type 1, type 2, and type 17 cytokine responses. The majority of studies identify IL-18 as a potential target for future COPD therapeutics to limit both the destructive and remodeling processes occurring in COPD lungs.     

Models of chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is a major global health problem and is predicted to become the third most common cause of death by 2020. Apart from the important preventive steps of smoking cessation, there are no other specific treatments for COPD that are as effective in reversing the condition, and therefore there is a need to understand the pathophysiological mechanisms that could lead to new therapeutic strategies. The development of experimental models will help to dissect these mechanisms at the cellular and molecular level. COPD is a disease characterized by progressive airflow obstruction of the peripheral airways, associated with lung inflammation, emphysema and mucus hypersecretion. Different approaches to mimic COPD have been developed but are limited in comparison to models of allergic asthma. COPD models usually do not mimic the major features of human COPD and are commonly based on the induction of COPD-like lesions in the lungs and airways using noxious inhalants such as tobacco smoke, nitrogen dioxide, or sulfur dioxide. Depending on the duration and intensity of exposure, these noxious stimuli induce signs of chronic inflammation and airway remodelling. Emphysema can be achieved by combining such exposure with instillation of tissue-degrading enzymes. Other approaches are based on genetically-targeted mice which develop COPD-like lesions with emphysema, and such mice provide deep insights into pathophysiological mechanisms. Future approaches should aim to mimic irreversible airflow obstruction, associated with cough and sputum production, with the possibility of inducing exacerbations.     

Gait mechanics in patients with chronic obstructive pulmonary disease

Background

Chronic obstructive pulmonary disease (COPD) is characterized by the frequent association of disease outside the lung. The objective of this study was to determine the presence of biomechanical gait abnormalities in COPD patients compared to healthy controls while well rested and without rest.

Methods

Patients with COPD (N = 17) and aged-matched, healthy controls (N = 21) walked at their self-selected pace down a 10-meter walkway while biomechanical gait variables were collected. A one-minute rest was given between each of the five collected trials to prevent tiredness (REST condition). Patients with COPD then walked at a self-selected pace on a treadmill until the onset of self-reported breathlessness or leg tiredness. Subjects immediately underwent gait analysis with no rest between each of the five collected trials (NO REST condition). Statistical models with and without covariates age, gender, and smoking history were used.

Results

After adjusting for covariates, COPD patients demonstrated more ankle power absorption in mid-stance (P = 0.006) than controls during both conditions. Both groups during NO REST demonstrated increased gait speed (P = 0.04), stride length (P = 0.03), and peak hip flexion (P = 0.04) with decreased plantarflexion moment (P = 0.04) and increased knee power absorption (P = 0.04) as compared to REST. A significant interaction revealed that peak ankle dorsiflexion moment was maintained from REST to NO REST for COPD but increased for controls (P < 0.01). Stratifying by disease severity did not alter these findings, except that step width decreased in NO REST as compared to REST (P = 0.01). Standardized effect sizes of significant effects varied from 0.5 to 0.98.

Conclusions

Patients with COPD appear to demonstrate biomechanical gait changes at the ankle as compared to healthy controls. This was seen not only in increased peak ankle power absorption during no rest but was also demonstrated by a lack of increase in peak ankle dorsiflexion moment from the REST to the NO REST condition as compared to the healthy controls. Furthermore, a wider step width has been associated with fall risk and this could account for the increased incidence of falls in patients with COPD.     

肺微生物组与慢性阻塞性肺疾病的研究进展

慢性阻塞性肺疾病（COPD）是一种慢性炎症性呼吸道疾病,其特征是持续气流受限和肺部炎症反应异常。气道内微生物是COPD恶化的主要原因,并且使气道中的炎症反应持续存在而促成COPD进展,这导致肺功能的进一步损害和巨大的医疗保健成本。近年来随着高通量测序技术的发展和运用,人类肺微生物组的研究逐渐成为热点。大量研究表明,COPD患者肺内存在明显不同的微生物群落,而且与COPD的疾病严重程度及恶化状态有关。肺微生物组学的研究有助于人们更全面地理解COPD患者肺内的微生态系统及其在该病恶化和进展中的作用。本文就肺微生物组在COPD中的研究进展作一综述,并探讨未来的研究前景。