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 bovine cerebrovascular endothelial cells stimulated with hemolysate were investigated. Upon incubation with hemolysate for 48 h, cell density was significantly 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 compared with controls. Simultaneous addition of CGS 26303 (10 and 100 microM) and hemolysate protected against cell loss and decreased cellular vacuolization caused by hemolysate. The levels of ET-1 and big ET-1 in the culture medium were decreased dose-dependently. More drastically, pretreatment with 100 microM 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 that suppression of ET-1 production by ECE inhibitors may prove to be efficacious for the treatment of hemolysate-induced cytotoxicity on cerebral endothelial cells.