[The change of concentration of endothelin derived from alveolar macrophages and in induced sputum in patients with chronic bronchitis]

Abstract

Objective: To evaluate the changes of levels of endothelin (ET) in induced sputum, the culture supernatants of alveolar macrophages (AMs) and the culture supernatants of alveolar macrophages (AMs) when cultivated with aminophylline and lipopolysaccharide (LPS) in patients with chronic bronchitis and COPD. Then to investigate the role of ET derived from AMs in chronic bronchitis and COPD.

Methods: Fourteen patients with chronic bronchitis and thirteen patients with COPD were studied. Fourteen healthy were enrolled as control. Bronchoscopy and bronchial alveolar lavage were performed routinely, BAL cells were count with hemacytometer and differentater with wright stain. Sputum induction with 4% saline was performed on twenty-six subjects. The levels of ET in BALF and in the culture supernatants of AMs were measured by radioimmunoassay methods.

Results: (1) The number of all cells, neutrophils and AMs in BALF of patients with chronic bronchitis and COPD were significantly higher than those of healthy control group (P < 0.01 respectively). (2) The levels of ET in the culture supernatants of AMs and induced sputum were higher in heathy than those in patients with chronic bronchitis and COPD (P < 0.01 respectively). But there were no differences between patients with chronic bronchitis and COPD (P > 0.05 respectively). (3) Positive correlation was found between the levels of ET in the culture supernatants of AMs and those in induced sputum (r = 0.741, P < 0.01), between the number of AMs and the levels of ET in induced sputum (r = 0.597, P < 0.01). (4) Negative correlation was found between FEV(1)% of predicted value and the levels of ET in the culture supernatants of AMs in patients with COPD (r = -0.828, P < 0.01), between FEV(1)% of predited value and the levels of ET in induced sputum in patients with COPD (r = -0.748, P < 0.05). (5) In the culture with aminophylline, the level of ET derived from AMs remained stable (P > 0.05). But in the culture with LPS, the level of ET was significantly higher than that in the culture with DMEM (P < 0.01).

Conclusions: (1) The characteristics of non-specific airway inflammation in patients with chronic bronchitis and COPD is the increased numbers of neutrophils and AMs. (2) AMs are perhaps important sources of ET in the lung. LPS can stimulate AMs to secrete more ET. ET derived from AMs takes part in development of COPD.