Thrombolysis in a rabbit stroke model using liposomal-encapsulated streptokinase

Plasminogen activators have been used for years to treat thrombotic crises. While some have focused on the development of more fibrin-specific thrombolytics, the authors have chosen to examine alternative methods of delivering thrombolytic proteins to clots. Specifically, the authors and others have shown that plasminogen activators are more effective when encapsulated in liposomes than when infused as free proteins. In this study, the authors have explored the potential benefits of encapsulating streptokinase (SK) in the treatment of strokes by comparing the effects of free intravenous SK and liposomal-encapsulated SK (LESK). Following simulation of a stroke in a rabbit model, the authors infused comparable doses of either LESK or SK to determine the effect of each on reperfusion. LESK showed a significantly improved clot dissolving time over free SK [LESK: 19.3±12.1 min.; free SK: 74.3±41.4 min.]. Thus, the thrombolytic efficacy of SK is improved by encapsulation in liposomes for this experimental rabbit model, presumably by preventing premature inactivation of SK prior to LESK arrival and rupture at the clot