Inhibition of tissue plasminogen activator inhibitor by defibrotide in atherosclerotic patients.

Defibrotide, an antithrombotic drug, was previously shown to activate fibrinolysis. In order to elucidate the relationship between defibrotide treatment and fibrinolysis, ten atherosclerotic patients were given 1200 mg/day defibrotide intravenously for 7 days and then 400 mg/day intramuscularly for another 20 days. t-PA antigen assessed before and after venous occlusion was not affected by the treatment. Tissue PAI activity significantly decreased and t-PA activity, measured after venous occlusion, increased after 8 and 28 days of treatment; both these changes disappeared after defibrotide was discontinued. No particular side effects were detected throughout the investigation. The study suggests that defibrotide increases t-PA activity by reducing PAI activity.