Concentration of endothelin in plasma and BALF fluid from asthmatic patients.

The bronchoconstrictive peptide endothelin-1 (ET-1) has been demonstrated in the airway epithelial and endothelial cells. In this study we investigated the pathophysiological significance of endothelin-1 in asthma. We addressed the issue by assessing the concentration of ET-1 in plasma and bronchoalveolar lavage fluid (BALF) in patients with a different intensity of asthma. Twenty one asthmatic patients (11 men,10 women) and 6 healthy control subjects (C) were included in the study. Eleven asthmatic patients were classified as moderate persistent asthma (SA), all of them were atopic, and another 10 were mild persistent asthmatics (AA). Lung function tests were carried out in all patients investigated. The ET-1 concentration was determined by an ELISA method in plasma and BALF. We found that the SA patients had the highest level of ET-1 (SA - 11.4 +/-3.6 fmol/ml; AA - 7.1 +/-2.7 fmol/ml; C - 5.6 +/-1.8 fmol/ml) in BALF. The same concerned the ET-1 level in plasma (SA - 27.8 +/-3.8 fmol/ml; AA - 18.1 +/-4.3 fmol/ml; C - 17.3 +/-3.0 fmol/ml). A positive correlation between the plasma ET-1 level and lung function indices was observed. We conclude that the higher levels of ET-1 in more severe asthma suggest that endothelins may contribute to the pathophysiology of the disease, its severity, and the regulation of bronchial tone.