ENDOTHELIAL-CELL ASSOCIATED ANTI-ELASTOLYTIC ACTIVITY

Addition of cultured and then carefully-washed bovine pulmonary artery endothelial cells (EC) decreased (p < 0.05) human neutrophil elastase activity (HNE) in vitro. HNE activity was also decreased (p < 0.05) b y addition of histone or protamine treated EC. However, addition of pa pain or trypsin treated EC decreased HNE activity less than addition o f untreated cells suggesting that a protein rather than a difference i n cell surface charge was responsible. Other observations suggest that EC anti-elastolytic activity was not due to binding of antiprotease f rom culture media but was dependent on EC protein synthesis. First, ad dition of EC grown previously in serum-free media decreased HNE activi ty the same (p < 0.05) as addition of EC cultured in media containing serum. Second, addition of EC treated beforehand with cycloheximide de creased HNE activity less than (p < 0.05) addition of untreated contro l EC. We conclude that EC most likely make and have antielastolytic ac tivity on their surfaces and speculate that EC associated anti-elastol ytic activity may modulate inflammatory, repair and other biologic pro cesses involving neutrophil elastase.