Peripheral airway epithelium in chronic airway inflammatory diseases. Expression of cytokines/chemokines and responses to growth factors. A study with an ultrathin bronchofiberscope.

To study the inflammatory responses of small airway epithelium in various airway disorders, we harvested living epithelial cells from very peripheral airways by employing a new ultrathin fiberscope. The expression levels of IL-8 or eotaxin when evaluated by reverse transcription-polymerase chain reaction (RT-PCR) were significantly increased in COPD and asthma respectively. We also studied the gene expression of transforming growth factor (TGF) -β-1, a potent fibrogenic factor, in small airway epithelium from smokers and patients with COPD. The expression levels of TGFβ-1 were elevated in smoking group and COPD than in non-smokers. Furthermore, TGFβ-1 mRNA levels correlated with the degrees of small airway obstruction as assessed by the measurements of flow-volume curves. Finally, we evaluated the growth responses of these cells to a veriety of growth factors, and found that hepatocyte growth factor (HGF) positively, and TGFβ-1 negatively regulated their proliferation in vitro.In conclusions, this approach with a new ultrathin bronchofiberscope promised as a good tool for evaluation of cellular and molecular changes in the small airways.