Neopterin in patients with COPD, asthma, and ACO: association with endothelial and lung functions

BACKGROUND AND OBJECTIVE

Endothelial dysfunction has been widely recognized in chronic airway diseases, including chronic obstructive pulmonary disease (COPD) and asthma; however, it remains unclear in asthma-COPD overlap (ACO). Neopterin (NP), a metabolite of guanosine triphosphate, is a novel biomarker for identifying the increased risk of adverse cardiovascular events. This study aims to investigate the association of NP with endothelial dysfunction and impaired lung function in COPD, asthma, and ACO patients.

METHODS

A total of 77 subjects were prospectively recruited. All the participants underwent lung function test, endothelial function evaluation, including pulse wave velocity (PWV) and flow-mediated dilation (FMD), and blood sample detection. Moreover, the effect of NP on endothelial cells (ECs) in anoxic environments was assessed in vitro.

RESULTS

Endothelial function was significantly decreased in the COPD and ACO patients compared with that in the healthy controls (P < 0.05). Forced expiratory volume in 1 s (FEV1) was negatively correlated with PWV and positively correlated with FMD (P < 0.05). NP was significantly increased in patients with chronic respiratory diseases compared with that in the control group, with COPD being the highest, followed by asthma, and ACO as the last (P < 0.05). The plasma level of NP exhibited negative correlations with FEV1 and positive correlations with PWV (P < 0.05). In vitro, a high level of NP increased the reactive oxygen species (ROS) and decreased the mitochondrial membrane potential (ΔΨm) of ECs dose-dependently in a hypoxic environment (P < 0.05).

CONCLUSION

NP was related to disease severity of chronic airway diseases and involved in the pathogenesis of endothelial dysfunction. A high NP level may contribute to endothelial dysfunction by increasing the oxidative stress of ECs dose-dependently in a hypoxic environment. Our findings may provide a novel evaluation and therapeutic target for endothelial dysfunction related to chronic airway diseases.

The prevalence and clinical features of asthma-COPD overlap (ACO) definitively diagnosed according to the Japanese Respiratory Society Guidelines for the Management of ACO 2018

Background Asthma-COPD overlap (ACO) is a disease that shares clinical features of both asthma and COPD. The purpose of this study is to investigate the prevalence and clinical features of ACO. Methods We retrospectively reviewed data for 170 patients with persistent airflow limitation and diagnosed them according to "The Japanese Respiratory Society Guidelines for the Management of ACO 2018". Results Of the 170 patients, 111 were diagnosed as follows : COPD (74 patients, 66.6%), ACO (34 patients, 30.6%), and asthma (3 patients, 2.8%). There was no significant difference in clinical features between ACO and COPD patients. The following pulmonary function tests were significantly lower in ACO than in COPD patients : forced expiratory volume in 1 second/forced vital capacity, peak expiratory flow, maximal mid-expiratory flow, and the maximum expiratory flow at 50%and75%. The following respiratory impedance parameters were significantly higher in ACO than in COPD patients : respiratory resistance (Rrs) at 5 Hz (R5), Rrsat 20 Hz (R20), R5-R20, and low-frequency reactance area. Conclusions About 30% of patients with persistent airflow limitation were diagnosed with ACO. ACO patients had lower lung function and higher respiratory impedance compared with COPD patients. J. Med. Invest. 66 : 157-164, February, 2019.

Challenges in the management of asthma associated with smoking-induced airway diseases

INTRODUCTION

Smoking-induced airway diseases such as chronic bronchitis, emphysema, and small airway dysfunction contribute to the chronic respiratory symptoms experienced by adults with asthma, including those with spirometric chronic obstructive pulmonary disease (COPD), termed asthma-COPD overlap (ACO). Drug treatment of symptomatic smokers with asthma or ACO is uncertain due to their exclusion from most clinical trials.

AREAS COVERED

This review summarizes evidence for the efficacy of small molecule drugs used in the clinic to treat current and former smokers with a diagnostic label of asthma or ACO. Other therapeutic interventions are reviewed, including smoking cessation and biologics.

EXPERT OPINION

Clinical trials and observational studies suggest that smoking cessation and approved drugs used to treat non-smokers with asthma produce clinical benefits in smokers with asthma or ACO, although the overall quality of evidence is low. The efficacy of some treatments for asthma is altered in current smokers, including reduced responsiveness to short-term inhaled corticosteroids and possibly improved responsiveness to leukotriene receptor antagonists. Preliminary findings suggest that low-dose theophylline, statins, and biologics, such as omalizumab, mepolizumab, and dupilumab, may improve clinical outcomes in smokers with asthma or ACO. Improved phenotyping and endotyping of asthma and smoking-induced airway diseases should lead to better targeted therapies.