The activity of rt-PA increases only 72-fold when exposed to fibrin. The clot-busting activity of DSPA increases about 13,000-fold when exposed to fibrin. Also, rt-PA has been shown to promote brain cell death in some animal studies. rt-PA is administered to a small percentage of stroke patients because current protocols allow treatment only within three hours of stroke onset.
Ischemic strokes are caused when a blood clot or series of clots block blood supply to the brain. The only Food and Drug Administration-approved clot buster for treating ischemic stroke is intravenous recombinant tissue plasminogen activator, (rt-PA). Medcalf and Schleuning were pioneers in the cloning and the study of gene expression of t-PA and were among the first scientists to spot its potential use for heart attack.
CLOT BUSTER FOR STROKE ACTIVATOR
In the mid-1980s, Wolf-Dieter Schleuning, M.D., Ph.D., now chief scientific officer of the German biotechnological company PAION GmbH, found that the vampire bat enzyme was genetically related to the clot buster tissue plasminogen activator (t-PA) but was more potent. "When the vampire bat bites its victim, it secretes this powerful clot-dissolving (fibrinolytic) substance so that the victim's blood will keep flowing, allowing the bat to feed," Medcalf explains. NH & MRC senior research fellow at Monash University Department of Medicine at Box Hill Hospital in Victoria, Australia. DSPA targets and destroys fibrin, the structural scaffold of blood clots, says senior author Robert Medcalf, Ph.D. The vampire bat saliva-derived clot buster is called Desmodus rotundus salivary plasminogen activator (DSPA) or desmoteplase. 10 – A potent clot-busting substance originally extracted from the saliva of vampire bats may be used up to three times longer than the current stroke treatment window – without increasing the risk for additional brain damage, according to research reported in today's rapid access issue of Stroke: Journal of the American Heart Association.
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