Increased levels of angiopoietin-2 in induced sputum from smoking asthmatic patients

Summary Background Active cigarette smoking has detrimental effects on asthma morbidity and severity. Angiopoietin‐1 has been shown to protect the microvessels against plasma leakage, whereas angiopoietin‐2 enhances vascular permeability and subsequently induces airway mucosal oedema. Therefore, it is recently thought that angiopoietin‐2 may contribute to the pathophysiology of asthma. Objective To determine whether angiopoietin‐2 levels in the airways are associated with clinical profiles in smoking asthmatics. Methods We measured angiopoietin‐1 and ‐2 levels in induced sputum in 35 normal controls (18 non‐smokers and 17 smokers) and 49 asthmatics (24 non‐smokers and 25 smokers) before and after inhaled beclomethasone dipropionate (BDP: 800 μg/day) therapy for 12 weeks. Results Angiopoietin‐1 and ‐2 levels in induced sputum were significantly higher in asthmatics than in normal controls. Moreover, angiopoietin‐2 levels were significantly higher in smoking asthmatics than in non‐smoking asthmatics (P=0.0001). The airway vascular permeability index was also higher in smoking asthmatics than in non‐smoking asthmatics. Moreover, the angiopoietin‐2 level was positively correlated with the airway vascular permeability index (non‐smoking asthmatics: r=0.87, P