Effects of endothelin-converting enzyme inhibitors on hemolysate-induced morphological changes and production of endothelin-1 in bovine cerebrovascular endothelial cells

The effects of CGS 26303, a dual inhibitor of endothelin-converting enzyme (ECE) and neutral endopeptidase 24.11, and its prodrug, CGS 26393, on bovin e cerebrovascular endothelial cells stimulated with hemolysate were investi gated. Upon incubation with hemolysate for 48 h, cell density was significa ntly decreased, with concomitant increases in endothelin-1 (ET-1) (42 vs 11 pg/ml) and big ET-1 (79 vs 27 pg/ml) levels in culture medium when compare d with controls. Simultaneous addition of CGS 26303 (10 and 100 muM) and he molysate protected against cell loss and decreased cellular vacuolization c aused by hemolysate. The levels of ET-1 and big ET-1 in the culture medium were decreased dose-dependently. More drastically, pretreatment with 100 mu M CGS 26303 for 30 min decreased the production of ET-1 and big ET-1 by 94% and 87%, respectively, when compared with the untreated control. However, treatment with CGS 26393 was much less effective. These results suggest tha t suppression of ET-1 production by ECE inhibitors may prove to be efficaci ous for the treatment of hemolysate-induced cytotoxicity on cerebral endoth elial cells.