Potential role of pentosidine on susceptibility to small airway closure in elderly and smoking asthma.

Background: Small airway closure in asthma is determined by a complex interaction of structural and functional characteristics including lung elastic recoil. Recently, we determined that loss of elastic recoil might be attributable to pentosidine level in the airways. This study was designed to investigate the influences of aging and smoking on small airway closure in asthma.

Methods: Sixty-one patients with asthma (20 non-smoking young adult, 23 non-smoking elderly, and 18 smoking young adult) and 36 control subjects (12 non-smoking young adult, 11 non-smoking elderly, and 13 smoking young adult) were included. We assessed airway responses during methacholine provocation and calculated the closing index. In addition, we measured pentosidine levels in induced sputum from all study subjects.

Results: Pentosidine levels in induced sputum were markedly higher in asthmatic patients than in controls. In control subjects, the intergroup differences in pentosidine level among 3 subgroups were significant. Similarly, pentosidine levels were significantly higher in non-smoking elderly and smoking young adult asthmatics than in non-smoking young adult asthmatics. There was no significant difference in pentosidine levels between non-smoking elderly and smoking young adult asthmatics. The closing index was also significantly higher in non-smoking elderly and smoking young adult asthmatics than in non-smoking young adult asthmatics. Moreover, pentosidine levels in non-smoking elderly and smoking young adult asthmatics were closely correlated with closing index.

Conclusions: We determined the correlation of pentosidine level with susceptibility to small airway closure in elderly and smoking asthmatics. Our results might facilitate the understanding of elderly and smoking asthma.