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 Team discovers how bacteria exploit a chink in the body's armor
20.01.2017 | University of Illinois at Urbana-Champaign

nachricht Rabies viruses reveal wiring in transparent brains
19.01.2017 | Rheinische Friedrich-Wilhelms-Universität Bonn

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: Traffic jam in empty space

New success for Konstanz physicists in studying the quantum vacuum

An important step towards a completely new experimental access to quantum physics has been made at University of Konstanz. The team of scientists headed by...

Im Focus: How gut bacteria can make us ill

HZI researchers decipher infection mechanisms of Yersinia and immune responses of the host

Yersiniae cause severe intestinal infections. Studies using Yersinia pseudotuberculosis as a model organism aim to elucidate the infection mechanisms of these...

Im Focus: Interfacial Superconductivity: Magnetic and superconducting order revealed simultaneously

Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.

While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...

Im Focus: Studying fundamental particles in materials

Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales

Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...

Im Focus: Designing Architecture with Solar Building Envelopes

Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.

As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Sustainable Water use in Agriculture in Eastern Europe and Central Asia

19.01.2017 | Event News

12V, 48V, high-voltage – trends in E/E automotive architecture

10.01.2017 | Event News

2nd Conference on Non-Textual Information on 10 and 11 May 2017 in Hannover

09.01.2017 | Event News

 
Latest News

Helmholtz International Fellow Award for Sarah Amalia Teichmann

20.01.2017 | Awards Funding

An innovative high-performance material: biofibers made from green lacewing silk

20.01.2017 | Materials Sciences

Ion treatments for cardiac arrhythmia — Non-invasive alternative to catheter-based surgery

20.01.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>