T helper type 17-related cytokine expression is increased in the bronchial mucosa of stable chronic obstructive pulmonary disease patients

There are increased numbers of activated T lymphocytes in the bronchial mucosa of stable chronic obstructive pulmonary disease (COPD) patients. T helper type 17 (Th17) cells release interleukin (IL)-17 as their effector cytokine under the control of IL-22 and IL-23. Furthermore, Th17 numbers are increased in some chronic inflammatory conditions. To investigate the expression of interleukin (IL)-17A, IL-17F, IL-21, IL-22 and IL-23 and of retinoic orphan receptor RORC2, a marker of Th17 cells, in bronchial biopsies from patients with stable COPD of different severity compared with age-matched control subjects. The expression of IL-17A, IL-17F, IL-21, IL-22, IL-23 and RORC2 was measured in the bronchial mucosa using immunohistochemistry and/or quantitative polymerase chain reaction. The number of IL-22(+) and IL-23(+) immunoreactive cells is increased in the bronchial epithelium of stable COPD compared with control groups. In addition, the number of IL-17A(+) and IL-22(+) immunoreactive cells is increased in the bronchial submucosa of stable COPD compared with control non-smokers. In all smokers, with and without disease, and in patients with COPD alone, the number of IL-22(+) cells correlated significantly with the number of both CD4(+) and CD8(+) cells in the bronchial mucosa. RORC2 mRNA expression in the bronchial mucosa was not significantly different between smokers with normal lung function and COPD. Further, we report that endothelial cells express high levels of IL-17A and IL-22. Increased expression of the Th17-related cytokines IL-17A, IL-22 and IL-23 in COPD patients may reflect their involvement, and that of specific IL-17-producing cells, in driving the chronic inflammation seen in COPD.

Functional classes of bronchial mucosa genes that are differentially expressed in asthma

BACKGROUND

Asthma pathogenesis and susceptibility involves a complex interplay between genetic and environmental factors. Their interaction modulates the airway inflammation and remodelling processes that are present even in mild asthma and governs the appearance and severity of symptoms of airway hyperresponsiveness. While asthma is felt to develop as the result of interaction among many different genes and signalling pathways, only a few genes have been linked to an increased risk of developing this condition.

RESULTS

We report the results of expression microarray studies using tissue obtained from bronchial biopsies of healthy controls and of subjects with allergic asthma, both before and following inhaled corticotherapy. We identified 79 genes that show significant differences in expression (following Bonferroni cutoff using p < 6.6 x 10(-6) to correct for multiple testing) in asthmatics compared to controls at significance levels. These included 21 genes previously implicated in asthma, such as NOS2A and GPX3, as well as new potential candidates, such as ALOX15, CTSC and CX3CR1. The expression levels of one third of these transcripts were partially or completely corrected following inhaled corticosteroid therapy.

CONCLUSION

The study shows that bronchial biopsies obtained from healthy and asthmatic subjects display distinct expression profiles. These differences provide a global view of physiopathologic processes active in the asthmatic lung and may provide invaluable help to clarify the natural history of asthma.

IL-17-high asthma with features of a psoriasis immunophenotype

BACKGROUND

The role of IL-17 immunity is well established in patients with inflammatory diseases, such as psoriasis and inflammatory bowel disease, but not in asthmatic patients, in whom further study is required.

OBJECTIVE

We sought to undertake a deep phenotyping study of asthmatic patients with upregulated IL-17 immunity.

METHODS

Whole-genome transcriptomic analysis was performed by using epithelial brushings, bronchial biopsy specimens (91 asthmatic patients and 46 healthy control subjects), and whole blood samples (n = 498) from the Unbiased Biomarkers for the Prediction of Respiratory Disease Outcomes (U-BIOPRED) cohort. Gene signatures induced in vitro by IL-17 and IL-13 in bronchial epithelial cells were used to identify patients with IL-17-high and IL-13-high asthma phenotypes.

RESULTS

Twenty-two of 91 patients were identified with IL-17, and 9 patients were identified with IL-13 gene signatures. The patients with IL-17-high asthma were characterized by risk of frequent exacerbations, airway (sputum and mucosal) neutrophilia, decreased lung microbiota diversity, and urinary biomarker evidence of activation of the thromboxane B2 pathway. In pathway analysis the differentially expressed genes in patients with IL-17-high asthma were shared with those reported as altered in psoriasis lesions and included genes regulating epithelial barrier function and defense mechanisms, such as IL1B, IL6, IL8, and β-defensin.

CONCLUSION

The IL-17-high asthma phenotype, characterized by bronchial epithelial dysfunction and upregulated antimicrobial and inflammatory response, resembles the immunophenotype of psoriasis, including activation of the thromboxane B2 pathway, which should be considered a biomarker for this phenotype in further studies, including clinical trials targeting IL-17.

Association of current smoking with airway inflammation in chronic obstructive pulmonary disease and asymptomatic smokers

BACKGROUND

Inflammation in the airways and lung parenchyma underlies fixed airway obstruction in chronic obstructive pulmonary disease. The exact role of smoking as promoting factor of inflammation in chronic obstructive pulmonary disease is not clear, partly because studies often do not distinguish between current and ex-smokers.

METHODS

We investigated airway inflammation in sputum and bronchial biopsies of 34 smokers with chronic obstructive pulmonary disease (9 Global initiative for Chronic Obstructive Lung Disease stage 0, 9 stage I, 10 stage II and 6 stage III) and 26 asymptomatic smokers, and its relationship with past and present smoking habits and airway obstruction.

RESULTS

Neutrophil percentage, interleukin-8 and eosinophilic-cationic-protein levels in sputum were higher in chronic obstructive pulmonary disease (stage I-III) than asymptomatic smokers. Inflammatory cell numbers in bronchial biopsies were similar in both groups. Current smoking correlated positively with macrophages: in bronchial biopsies in both groups, and in sputum in chronic obstructive pulmonary disease. Pack-years smoking correlated positively with biopsy macrophages only in chronic obstructive pulmonary disease.

CONCLUSION

Inflammatory effects of current smoking may mask the underlying ongoing inflammatory process pertinent to chronic obstructive pulmonary disease. This may have implications for future studies, which should avoid including mixed populations of smokers and ex-smokers.

Distinctive characteristics of bronchial reticular basement membrane and vessel remodelling in chronic obstructive pulmonary disease (COPD) and in asthma: they are not the same disease

AIMS

This study compared reticular basement membrane (Rbm) and vascular remodelling within the bronchial mucosa of subjects with chronic obstructive pulmonary disease (COPD) with those from patients with asthma, to test the 'Dutch hypothesis' of whether these are essentially the same or different pathological conditions.

METHODS AND RESULTS

Bronchoscopic biopsies were stained with anti-collagen IV antibody; 18 current smoking COPD, 10 symptomatic asthmatics and 13 healthy non-smoking controls were studied. The Rbm in COPD was fragmented, non-homogeneous, variable in thickness and hypervascular, whereas in asthma the Rbm was compact and homogeneous with no evidence of increased vascularity compared to controls. Length of Rbm splitting presented as percentage of Rbm length was used to measure fragmentation; it was greater in COPD than in controls and asthmatics [median (range) 20.7% (0.4-68.5) versus 5.3% (0.0-21.7) versus 1.5% (0.0-15.1), P < 0.001]. The number of Rbm vessels/mm Rbm [median (range) 10.1 (1.6-23.0) versus 4.5 (0.0-26.4) versus 4.4 (0.4-8.1), P < 0.01] and area of Rbm vessels, μm(2) /mm Rbm [median (range) 953 (115-2456) versus 462 (0-3263) versus 426 (32-2216), P < 0.05] was also increased in COPD compared to normal subjects and asthmatics.

CONCLUSIONS

The characteristics of Rbm remodelling are quite different in asthma and COPD.

Effects of inhaled corticosteroids on airway inflammation in chronic obstructive pulmonary disease: a systematic review and meta-analysis

Background:

Chronic obstructive pulmonary disease (COPD) is characterized by chronic inflammation in the small airways. The effect of inhaled corticosteroids (ICS) on lung inflammation in COPD remains uncertain. We sought to determine the effects of ICS on inflammatory indices in bronchial biopsies and bronchoalveolar lavage fluid of patients with COPD.

Methods:

We searched Medline, Embase, Cinahl, and the Cochrane database for randomized, controlled clinical trials that used bronchial biopsies and bronchoalveolar lavage to evaluate the effects of ICS in stable COPD. For each chosen study, we calculated the mean differences in the concentrations of inflammatory cells before and after treatment in both intervention and control groups. These values were then converted into standardized mean differences (SMD) to accommodate the differences in patient selection, clinical treatment, and biochemical procedures that were employed across the original studies. If significant heterogeneity was present (P < 0.1), then a random effects model was used to pool the original data; otherwise, a fixed effects model was used.

Results:

We identified eight original studies that met the inclusion criteria. Four studies used bronchial biopsies (n =102 participants) and showed that ICS were effective in reducing CD4 and CD8 cell counts (SMD, −0.52 units and −0.66 units, 95% confidence interval). The five studies used bronchoalveolar lavage fluid (n =309), which together showed that ICS reduced neutrophil and lymphocyte counts (SMD, −0.64 units and −0.64 units, 95% confidence interval). ICS on the other hand significantly increased macrophage counts (SMD, 0.68 units, 95% confidence interval) in bronchoalveolar lavage fluid.

Conclusion:

ICS has important immunomodulatory effects in airways with COPD that may explain its beneficial effect on exacerbations and enhanced risk of pneumonia.

Where We Stand: Lung Organotypic Living Systems That Emulate Human-Relevant Host-Environment/Pathogen Interactions

Lung disorders such as chronic obstructive pulmonary disease (COPD) and lower respiratory tract infections (LRTIs) are leading causes of death in humans globally. Cigarette smoking is the principal risk factor for the development of COPD, and LRTIs are caused by inhaling respiratory pathogens. Thus, a thorough understanding of host–environment/pathogen interactions is crucial to developing effective preventive and therapeutic modalities against these disorders. While animal models of human pulmonary conditions have been widely utilized, they suffer major drawbacks due to inter-species differences, hindering clinical translation. Here we summarize recent advances in generating complex 3D culture systems that emulate the microarchitecture and pathophysiology of the human lung, and how these platforms have been implemented for studying exposure to environmental factors, airborne pathogens, and therapeutic agents.

Early Airway Pathological Changes in Children: New Insights into the Natural History of Wheezing

Asthma is a heterogeneous condition characterized by reversible airflow limitation, with different phenotypes and clinical expressions. Although it is known that asthma is influenced by age, gender, genetic background, and environmental exposure, the natural history of the disease is still incompletely understood. Our current knowledge of the factors determining the evolution from wheezing in early childhood to persistent asthma later in life originates mainly from epidemiological studies. The underlying pathophysiological mechanisms are still poorly understood. The aim of this review is to converge epidemiological and pathological evidence early in the natural history of asthma to gain insight into the mechanisms of disease and their clinical expression.

HO1 mRNA and Protein do not Change in Parallel in Bronchial Biopsies of Patients After Long Term Exposure to Sulfur Mustard

Sulfur mustard (SM), is an alkylating agent and has been emerged as a chemical weapon in various battlefields. More recently, SM was employed in the Iraq conflict against Iranian military forces and civilians. Nowadays there are more than 40,000 people suffering from pulmonary lesions special chronic obstructive pulmonary disease (COPD) due to mustard gas in Iran. SM causes the endogenous production of reactive oxygen species (ROS).Heme oxygenases (HOs) are the rate-limiting enzyme for heme metabolism. Numerous studies have confirmed that HOs are concerned in diverse biological processes such as anti-oxidation.The present study was undertaken to consider the regulation of HO-1 and HO-2 n the human airway wall, and to suggest a probable role that HOs may play in cellular defense against oxidative stress due to SM.In this research ten unexposed SM individuals and twenty SM exposed patients were included. Evaluation of HO-1& HO -2 expressions in unexposed and SM exposed patients samples was performed by semiquantitative RT-PCR, real-time RT-PCR and Immunohistochemistry analysis.While unexposed SM samples expressed same levels of HOs, expression level of HO-1 was upregulated about 3.58 ± 1.93 folds in SM exposed patients in comparison with unexposed ones, we could not find any difference in expression of HO-2 n two groups. In contrast, Immunohistochemistry results showed negative HO-1 protein expression in SM injured patients.Our results revealed that HO1 may plays an important role in cellular protection against oxidative stress due to mustard gas toxicity in airway wall of SM exposed patients at mRNA level, but translational modifications might cause decrease in the amount of HO1 protein.