Arterial and bronchoalveolar lavage fluid endothelin-1 concentration in asthma

Endothelins are a family of peptide mediators that have a number of biological properties, including the ability to act as bronchoconstrictors and vasoconstrictors of isolated airways and vessels. Endothelin-1 (ET-1) is the more potent peptide compared with the other two peptides of the family. To examine a possible involvement of ET- 1 in the pathogenesis of asthma, we measured arterial ET-1 levels in 11 patients with atopic asthma during attack and during remission, and in 11 healthy control subjects. We also performed fiberoptic bonchoscopy and bronchoalveolar lavage (BAL) to measure ET-1 levels in the 11 asthmatic patients during remission, and in the 11 healthy control subjects. ET-1 concentrations in arterial blood and in BAL were measured by a radioimmunoassay method. Arterial ET-1 levels were very significantly higher in asthma attack (3.67 +/- 0.51 pg ml(-1)) and in asthma remission (2.65 +/- 10.62 pg ml(-1)) compared with those of the healthy controls (1.37 +/- 0.14 pg ml(-1)) (P < 0.001). Arterial ET-1 levels were also very significantly higher during asthma attack compared with those in asthma remission (P < 0.001). BAL ET-1 levels were significantly higher in asthma remission (0.73 +/- 0.53 pmol g(-1)) compared with those of the healthy controls (0.16 +/- 0.02 pmol g(-1)) (P < 0.05). No correlation was observed between arterial and BAL ET-1 levels, PaO2 and peak expiratory flow rate (PEFR). These data are consistent with the hypothesis that ET-1 contributes to the pathophysiology of asthma. However, it is likely that the true importance of this vasoconstrictor peptide will only be revealed by pharmacological studies with specific receptor antagonists.