RESUMEN
Endothelin-1 [ET-1] is a potent bronchoconstrictor which may have a role in the pathogenesis of asthma. To clarify the interrelation between ET-1 and bronchial asthma, the concentrations of ET-1 in plasma and BAL fluid were measured [by ELISA technique] in [10] healthy subjects, [10] patients with atopic asthma treated with bronchodilators alone [Group 1], and [10] patients with atopic ashma treated with inhaled an/or oral corticosteroids [Group II]. Pulmonary functions [FEV1% predicted and FEF25-75% predicated] and the provocation concentrations of methacholine required to reduce FEV1 by 20% of the prechallenge baseline [PD20 were also measured. There was no significant difference in the plasma ET-1 level among either the control group and group 1 [15.95 +/- 6.5 pg/ml versus 17.84 +/- 7.8 pg/ml][and group II [15.95 +/- 6.5 pg/ml versus 16.75 +/- 6.7 pg/ml] or group I and II [17.84 +/- 6.7 pg/ml]. There was a significant increase in BAL fluid ET-1 levels in both the non steroid treated patients with asthma [Group I] and the steroid treated patients [Group II] compared with the normal subjects [20.94 +/- 3.96 pg/ml versus 15.61 +/- 3.37 pg/ml][and [16.03 +/- 3.5 pg/ml] respectively. There was statistically significant difference in BAL ET-1 level between Group II and group I indicating that ET-1 level may be modulated by corticosteroid therapy. In group I and II there was a significant negative correlation between the BAL ET-1 concentrations and ventilatory functions [% predicated FEV1 and FEF25-75].No correlation between BAL fluid ET-1 concentrations and bronchial reactivity or plasma ET-1 level was found in either Group I and II. These findings indicate that the potent bronchoconstricitive substance, endotheline, may contribute to pathogenesis of airflow obstruction in asthma