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 study was to reevaluate these findings and to investigate whether retinoids 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 secretion of plasminogen activator inhibitor-1. In patients treated with isotretinoin or etretinate these findings were confirmed, showing enhanced baseline tissue plasminogen activator concentrations in plasma in association with unchanged levels of plasminogen activator inhibitor-1 and von Willebrand factor. These findings are consistent with chronically augmented tissue plasminogen activator secretion without evidence of endothelial cell damage and may be of importance for the interpretation of the safety of lon-term therapy with regard to retinoid-induced hyperlipemia and the development of cardiovascular disease.