Endothelin-1 in stable bronchiectasis.

Endothelin (ET)-1 has been suggested to promote neutrophil adhesion to endothelium, migration to inflamed areas, and release of elastase. ET-1 might therefore play a role in the pathogenesis of bronchiectasis, a chronic inflammatory and infective airway disease which is still poorly understood. Thirty five patients with stable bronchiectasis (20 females, mean age+/-SD 49.1+/-15.0 yrs) and 18 control subjects (8 females, 49.4+/-11.3 yrs) were recruited prospectively. The ET-1 levels in serum and sputum were measured by commercially available enzyme linked immunosorbent assay (ELISA) kits. Patients with Pseudomonas aeruginosa in their sputum had a significantly higher serum level of ET-1 (median 25.8, interquartile range 13-43.9 pg x mL(-1)) than patients without P. aeruginosa (0, 0-10.5 pg x mL(-1); p=0.0004) and healthy control subjects (4.6, 0-16.3 pg x mL(-1); p=0.002). However, patients with and without P. aeruginosa infection had no significant difference in sputum ET-1 level (p=0.15). There was no correlation between serum or sputum ET-1 levels with the serum and sputum levels of the interleukin (IL)-1beta, IL-8 and tumour necrosis factor (TNF)-alpha; the number of bronchiectasis lung lobes; and spirometry. Serum ET-1 level correlated with 24 h sputum volume for the bronchiectasis patients (r=0.51, p=0.002). The results, therefore, suggest a significant pathogenic role for endothelin-1 among Pseudomonas aeruginosa-infected patients with bronchiectasis. Further studies should be performed to evaluate the clinico-pathological correlation and expression of endothelin-1 in bronchiectasis.