Vampire bats yield potent clot buster for ischemic stroke.

While tissue-type plasminogen activator (tPA) is currently the standard "clot-busting" drug used to treat patients with acute ischemic stroke, another new option for treatment is now under clinical study. Desmodus rotundus plasminogen activator (DSPA), an enzyme found in the saliva of vampire bats, may offer another therapeutic option instead of tPA, a current therapy for stroke. Animal research indicates that tPA may mediate neuronal death as well as increase systemic plasminogen consumption and fibrinogenolysis. Conversely, DSPA's activity is dependent on the presence of fibrin and therefore has not been associated with the systemic plasminogen consumption and fibrinogenolysis that potentially may occur in those receiving tPA. In animal studies, tPA was found to exhibit "inherent neurotoxic properties" not seen with DSPA. In addition, DSPA may be administered up to 9 hours after the onset of symptoms, unlike tPA, which cannot be given after 3 hours without potential risk of additional brain injury. Phase II clinical trials have demonstrated a positive result in human subjects. Phase III trials are currently under way in stroke populations.