Desmoteplase / PAION (First catch your bat...)
Thu Jan 9 WASHINGTON (Reuters) - An enzyme that lets vampire bats freely slurp blood from their prey may help stroke victims survive, and do it more safely than the only currently approved treatment, Australian researchers reported on Thursday.
The compound stops blood from clotting and is similar to a commercial clot-dissolving drug, the researchers report in this week's issue of the journal Stroke.
But the bat saliva enzyme -- called Desmodus rotundus salivary plasminogen activator, or desmoteplase -- is hundreds of times more powerful than current drugs.
Desmoteplase destroys fibrin, the structural scaffold of blood clots, said Robert Medcalf of Monash University in Victoria, Australia.
"When the vampire bat bites its victim, it secretes this powerful clot-dissolving substance so that the victim's blood will keep flowing, allowing the bat to feed," Medcalf said in a statement.
Many scientists have looked to the saliva of bloodsucking animals such as bats and leeches, as well as insects like ticks, for drugs that can help stop blood clots, for use in treating not only stroke but also heart attacks. Such animals often produce natural anticoagulants.
Dozens of drugs based on such compounds are in development.
Desmoteplase is being developed by PAION, a biopharmaceutical company based in Aachen, Germany. It is nearing final phase II/III trials in stroke victims.
Researchers at the company found that desmoteplase was genetically related to the clotbuster tissue plasminogen activator, known as alteplase or tPA and made by Genentech.
For the Stroke study, the Australian team injected either desmoteplase or t-PA into the brains of mice, then watched how their brain cells survived. TPA could kill brain cells but desmoteplase did not, they reported.
This could mean desmoteplase has the potential to help many more stroke victims than tPA -- because it could be given for many hours after a stroke, Medcalf said. TPA has to be given during a three-hour window of opportunity -- during which many people do not even realize they have suffered a stroke.
"This report provides data suggesting a potential advantage of a type of plasminogen activator derived from bat saliva over tPA, the only Food and Drug Administration (news - web sites)-approved treatment for selected patients with acute ischemic stroke," Dr. Larry Goldstein, chair of the American Stroke Association Advisory Committee, said in a statement.
"It needs to be understood that this study is limited to mice without stroke and focused only on toxicity," he added. Whether it actually helps stroke victims remains to be seen, he added. |
