Kimihiro Takeyabu

Increased levels of interleukin-8 in BAL fluid from smokers susceptible to pulmonary emphysema

Background: It has previously been shown that smokers with computed tomographic (CT) evidence of subclinical emphysema have signs of neutrophil activation, despite having no appreciable increase in the number of neutrophils in their bronchoalveolar lavage (BAL) fluid. Methods: The levels of the following chemoattractants in BAL fluid from 61 community based older volunteers classified into four groups according to current smoking status and the presence or absence of emphysema were determined: interleukin 8 (IL-8), epithelial neutrophil activating protein 78 (ENA-78) and leukotriene B4 (LTB4) which are primarily chemotactic for neutrophils; monocyte chemoattractant protein 1 (MCP-1) and macrophage inflammatory protein-1α (MIP-1α) which are predominantly chemotactic for mononuclear leucocytes. Results: Of the five chemoattractants studied, only the level of IL-8 in BAL fluid clearly distinguished between subjects with and without emphysema among current smokers (median values 34.7 and 12.2 pg/ml, respectively, p<0.01). In addition, the levels of IL-8 and neutrophil elastase-α1 protease inhibitor complex in BAL fluid were significantly correlated (r=0.65, p<0.01). There was no difference in either the release of IL-8 from cultured alveolar macrophages at 24 hours or the expression of IL-8 messenger RNA of alveolar macrophages in the two groups of current smokers with and without emphysema. Conclusion: An accelerated response of IL-8 to chronic smoking is a factor that characterises those smokers who are susceptible to pulmonary emphysema, although the cellular source of IL-8 remains to be determined.

Cysteine proteinases and cystatin C in bronchoalveolar lavage fluid from subjects with subclinical emphysema

This study examined the role of cysteine proteinases and their inhibitor in the development of emphysema in comparison with neutrophil elastase (NE) complexed with alpha1-protease inhibitor (NE-alpha1-PI), which was previously demonstrated to be increased in bronchoalveolar lavage (BAL) fluid from subjects with subclinical emphysema. Eight nonsmokers and 31 current smokers with (n=17) and without (n=14) emphysema, as evidenced by lung computed tomographic scans, were studied. The concentrations of immunologically detected cathepsin L and cystatin C, but not cathepsin B, were significantly increased in BAL fluid from the smokers with emphysema compared with those without emphysema, although the activity of cathepsin L, measured using a synthetic substrate and cathepsin L, released from cultured alveolar macrophages at 24 h, did not show any significant difference between the two groups. When comparison was made only for the subjects aged <60 yrs, the difference between the two groups disappeared for cathepsin L, but remained for NE-alpha1-PI. There was no significant correlation between the level of cathepsin L and that of NE-alpha1-PI in BAL fluid from the subjects with emphysema. In conclusion, increased levels of cathepsin L and cystatin C were demonstrated in bronchoalveolar lavage fluid from subjects with subclinical emphysema. However, the roles of cathepsin L and neutrophil elastase in the development of emphysema may vary between subjects and between the young and the old.

Decline in FEV1 in Community-Based Older Volunteers with Higher Levels of Neutrophil Elastase in Bronchoalveolar Lavage Fluid

Background: Neutrophil elastase (NE) is thought to be one of the key proteinases in the development of chronic obstructive pulmonary disease (COPD). Previously, we have shown that the NE-α1-proteinase inhibitor (NE-α1PI) complex in bronchoalveolar lavage (BAL) fluid was markedly elevated in asymptomatic smokers who had subclinical emphysema on CT scans. We proposed that excessive NE-α1PI complex in BAL fluid was a factor which might differentiate smokers who were developing emphysema from others. Objective: In this study, we addressed the question of whether elevated levels of the NE-α1PI complex in BAL fluid are linked to the accelerated decline in pulmonary functions in those subjects. Methods: We conducted a follow-up study to analyze the decline in FEV1 for 4.3 years on average for 26 community-based volunteers who had received pulmonary function tests, CT scans and BAL. The levels of the NE-α1PI complex in BAL fluid and in plasma was measured. Results: Neither pulmonary function measurements nor the presence of emphysema on CT scans could predict the decline in FEV1. The number of inflammatory cells in BAL fluid was also not an indicator of progression. By contrast, subjects with higher levels of the NE-α1PI complex in BAL fluid had a significantly accelerated decline in FEV1 compared to those with lower levels. Conclusion: These data seem to support the hypothesis that NE in the lung is related to the onset and/or progression of COPD.

Role of secretory leukocyte protease inhibitor in the development of subclinical emphysema.

Secretory leukocyte protease inhibitor (SLPI) is a potent inhibitor of human leukocyte elastase. In some chronic airway diseases, the level of SLPI is decreased in sputum, leading to the continuation of neutrophil inflammation. In this study, the role of SLPI in subclinical pulmonary emphysema was examined. Sequential bronchoalveolar lavage was performed in an attempt to separately evaluate the levels of SLPI in the large airways and in the peripheral airways for two groups of smokers. One group had subclinical emphysema by computed-tomography scans and one group did not. SLPI localized in alveolar macrophages (AM) was also assessed. The level of SLPI was significantly elevated in the peripheral airways from the subjects with emphysema compared to those without emphysema (1589.2±353.9 versus 729.1±31.0 ng·mL−1), although it was similar in the large airways (3442.3±499.6 versus 2535.7±578.8 ng·mL−1). There was a trend for higher amount of SLPI to be released from AM in subjects with subclinical emphysema, although this did not reach statistical significance. In conclusion, there is compensatory upregulation of secretory leukocyte protease inhibitor in peripheral airways in subclinical pulmonary emphysema, which is in sharp contrast to the decreased level of secretory leukocyte protease inhibitor reported in some chronic airway diseases.

Distinct Phenotypes of Cigarette Smokers Identified by Cluster Analysis of Patients with Severe Asthma

RATIONALE Smoking may have multifactorial effects on asthma phenotypes, particularly in severe asthma. Cluster analysis has been applied to explore novel phenotypes, which are not based on any a priori hypotheses. OBJECTIVES To explore novel severe asthma phenotypes by cluster analysis when including cigarette smokers. METHODS We recruited a total of 127 subjects with severe asthma, including 59 current or ex-smokers, from our university hospital and its 29 affiliated hospitals/pulmonary clinics. Twelve clinical variables obtained during a 2-day hospital stay were used for cluster analysis. After clustering using clinical variables, the sputum levels of 14 molecules were measured to biologically characterize the clinical clusters. MEASUREMENTS AND MAIN RESULTS Five clinical clusters were identified, including two characterized by high pack-year exposure to cigarette smoking and low FEV1/FVC. There were marked differences between the two clusters of cigarette smokers. One had high levels of circulating eosinophils, high IgE levels, and a high sinus disease score. The other was characterized by low levels of the same parameters. Sputum analysis revealed increased levels of IL-5 in the former cluster and increased levels of IL-6 and osteopontin in the latter. The other three clusters were similar to those previously reported: young onset/atopic, nonsmoker/less eosinophilic, and female/obese. Key clinical variables were confirmed to be stable and consistent 1 year later. CONCLUSIONS This study reveals two distinct phenotypes of severe asthma in current and former cigarette smokers with potentially different biological pathways contributing to fixed airflow limitation. Clinical trial registered with www.umin.ac.jp (000003254).

Distinct Phenotypes of Smokers with Fixed Airflow Limitation Identified by Cluster Analysis of Severe Asthma

Rationale: Smoking may have multifactorial effects on asthma phenotypes, particularly in severe asthma. Cluster analysis has been applied to explore novel phenotypes, which are not based on any a priori hypotheses. Objectives: To explore novel severe asthma phenotypes by cluster analysis when including smoking patients with asthma. Methods: We recruited a total of 127 subjects with severe asthma, including 59 current or ex‐smokers, from our university hospital and its 29 affiliated hospitals/pulmonary clinics. Clinical variables obtained during a 2‐day hospital stay were used for cluster analysis. After clustering using clinical variables, the sputum levels of 14 molecules were measured to biologically characterize the clinical clusters. Results: Five clinical clusters, including two characterized by low forced expiratory volume in 1 second/forced vital capacity, were identified. When characteristics of smoking subjects in these two clusters were compared, there were marked differences between the two groups: one had high levels of circulating eosinophils, high immunoglobulin E levels, and a high sinus score, and the other was characterized by low levels of the same parameters. Sputum analysis revealed intriguing differences of cytokine/chemokine pattern in these two groups. The other three clusters were similar to those previously reported: young onset/atopic, nonsmoker/less eosinophilic, and female/obese. Key clinical variables were confirmed to be stable and consistent 3 years later. Conclusions: This study reveals two distinct phenotypes with potentially different biological pathways contributing to fixed airflow limitation in cigarette smokers with severe asthma.