RETINOIDS AND FIBRINOLYSIS

Vitamin A and its analogues have been reported to increase the release of tissue plasminogen activator in vitro. The aim of the present stud y was to reevaluate these findings and to investigate whether retinoid s in doses used in dermatological therapy could enhance the release of endothelial fibrinolytic factors, Our results showed that endothelial cells incubated in vitro with retinoic acid increased the release of tissue plasminogen activator to the supernatant without concomitant se cretion of plasminogen activator inhibitor-1. In patients treated with isotretinoin or etretinate these findings were confirmed, showing enh anced baseline tissue plasminogen activator concentrations in plasma i n association with unchanged levels of plasminogen activator inhibitor -1 and von Willebrand factor. These findings are consistent with chron ically augmented tissue plasminogen activator secretion without eviden ce of endothelial cell damage and may he of importance for the interpr etation of the safety of longterm therapy with regard to retinoid-indu ced hyperlipemia and the development of cardiovascular disease.