Approach to the Peripheral Airway Epithelial Cells by an Ultrathin Bronchoscope(Bronchoscopy in Non-tumorous Pulmonary Disorders)(The 23rd Annual Congress of the Japan Society for Bronchology)

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The inflammatory changes in small airways have been believed to be important in the pathogenesis of chronic obstructive pulmonary disease(COPD). We successfully harvested epithelial cells from these sites by using an ultrathin fibroptic bronchoscope BF2.7(Chest 106; 1443, 1994). We first evaluated IL-8 and ICAM-1 expression in small airway epithelium, both being important in the recruitment and activation of inflammatory cells such as neutrophils. The IL-8 and ICAM-1mRNA levels corrected by beta-actin transcripts were significantly more increased in COPD patients and smokers than non-smokers. Secondly, we studied the levels of TGF β-1 expression, an important growth factor in tissue remodeling. Heavily smoking volunteers(>1 packs/day), COPD patients and never-smokers underwent bronchoscopic examination after an informed consent, and epithelial cells from small airways were harvested. Levels of TGF β-1 mRNA/bata-actin transcripts were significantly higher in smokers and COPD patients than in non-smokers. The levels showed a positive correlation with daily cigarette consumption. Importantly, there was an inverse correlation between TGF β-1 mRNA and V25 on flow-volume curves. In conclusion, small airway epithelium of smokers and COPD expresses higher levels of IL-8, ICAM-1 and TGF β-1, which may be involved in neutrophil inflammation and irreversible airway obstruction found in small airways.