Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Vampire bat bite packs potent clot-busting potential for strokes

10.01.2003


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.



The vampire bat saliva-derived clot buster is called Desmodus rotundus salivary plasminogen activator (DSPA) or desmoteplase. DSPA targets and destroys fibrin, the structural scaffold of blood clots, says senior author Robert Medcalf, Ph.D. NH & MRC senior research fellow at Monash University Department of Medicine at Box Hill Hospital in Victoria, Australia.

"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.


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. 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.

The only Food and Drug Administration-approved clot buster for treating ischemic stroke is intravenous recombinant tissue plasminogen activator, (rt-PA). Ischemic strokes are caused when a blood clot or series of clots block blood supply to the brain. rt-PA is administered to a small percentage of stroke patients because current protocols allow treatment only within three hours of stroke onset. Also, rt-PA has been shown to promote brain cell death in some animal studies.

The clot-busting activity of DSPA increases about 13,000-fold when exposed to fibrin. The activity of rt-PA increases only 72-fold when exposed to fibrin.

Researchers injected either DSPA or rt-PA into the brains of mice, then tracked the survival of brain cells. They discovered that while DSPA zeros in on fibrin, it had no affect on two brain receptors that can promote brain damage, Medcalf says. In contrast, rt-PA greatly enhanced the degree of brain cell death following receptor activation and may therefore be detrimental if it’s delivered too long after stroke onset.

The highly fibrin-specific activity demonstrated by DSPA may be an important advantage over rt-PA. It is this single-minded clot-busting action that has stroke researchers especially intrigued because while rt-PA is effective at breaking up and dissolving clots, it must be given quickly – within just three hours of the onset of stroke symptoms. By contrast, Medcalf says DSPA could be a safe treatment option for a longer period since it has no detrimental effect on brain cells. The three-hour time window often allows insufficient time for patients to undergo imaging tests to determine that they have a true ischemic stroke before rt-PA can initiated, he says.

"This report provides data suggesting a potential advantage of a type of plasminogen activator derived from bat saliva over t-PA, the only FDA-approved treatment for selected patients with acute ischemic stroke," says Larry Goldstein, M.D., chairperson of the American Stroke Association Advisory Committee. "It needs to be understood that this study is limited to mice without stroke and focused only on toxicity. Whether this approach will prove either safe or efficacious in improving stroke outcomes requires further testing."

Goldstein is director of the Center for Cerebrovascular Disease at Duke University in Durham, N.C.

DSPA is being tested up to nine hours after stroke onset in human stroke patients in Europe, Asia and Australia. A U.S. study could begin this year, Schleuning says. Other co-authors are Gabriel T. Liberatore, Ph.D, André Samson; and Christopher Bladin, M.D.


###
CONTACT: For journal copies only,
please call: (214) 706-1396
For other information, call:
Carole Bullock: (214) 706-1279
Bridgette McNeill: (214) 706-1135

Carole Bullock | EurekAlert!
Further information:
http://www.americanheart.org/

More articles from Health and Medicine:

nachricht How cancer metastasis happens: Researchers reveal a key mechanism
19.01.2018 | Weill Cornell Medicine

nachricht Researchers identify new way to unmask melanoma cells to the immune system
17.01.2018 | Duke University Medical Center

All articles from Health and Medicine >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Artificial agent designs quantum experiments

On the way to an intelligent laboratory, physicists from Innsbruck and Vienna present an artificial agent that autonomously designs quantum experiments. In initial experiments, the system has independently (re)discovered experimental techniques that are nowadays standard in modern quantum optical laboratories. This shows how machines could play a more creative role in research in the future.

We carry smartphones in our pockets, the streets are dotted with semi-autonomous cars, but in the research laboratory experiments are still being designed by...

Im Focus: Scientists decipher key principle behind reaction of metalloenzymes

So-called pre-distorted states accelerate photochemical reactions too

What enables electrons to be transferred swiftly, for example during photosynthesis? An interdisciplinary team of researchers has worked out the details of how...

Im Focus: The first precise measurement of a single molecule's effective charge

For the first time, scientists have precisely measured the effective electrical charge of a single molecule in solution. This fundamental insight of an SNSF Professor could also pave the way for future medical diagnostics.

Electrical charge is one of the key properties that allows molecules to interact. Life itself depends on this phenomenon: many biological processes involve...

Im Focus: Paradigm shift in Paris: Encouraging an holistic view of laser machining

At the JEC World Composite Show in Paris in March 2018, the Fraunhofer Institute for Laser Technology ILT will be focusing on the latest trends and innovations in laser machining of composites. Among other things, researchers at the booth shared with the Aachen Center for Integrative Lightweight Production (AZL) will demonstrate how lasers can be used for joining, structuring, cutting and drilling composite materials.

No other industry has attracted as much public attention to composite materials as the automotive industry, which along with the aerospace industry is a driver...

Im Focus: Room-temperature multiferroic thin films and their properties

Scientists at Tokyo Institute of Technology (Tokyo Tech) and Tohoku University have developed high-quality GFO epitaxial films and systematically investigated their ferroelectric and ferromagnetic properties. They also demonstrated the room-temperature magnetocapacitance effects of these GFO thin films.

Multiferroic materials show magnetically driven ferroelectricity. They are attracting increasing attention because of their fascinating properties such as...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

10th International Symposium: “Advanced Battery Power – Kraftwerk Batterie” Münster, 10-11 April 2018

08.01.2018 | Event News

See, understand and experience the work of the future

11.12.2017 | Event News

Innovative strategies to tackle parasitic worms

08.12.2017 | Event News

 
Latest News

Let the good tubes roll

19.01.2018 | Materials Sciences

How cancer metastasis happens: Researchers reveal a key mechanism

19.01.2018 | Health and Medicine

Meteoritic stardust unlocks timing of supernova dust formation

19.01.2018 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>