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 Inselspital: Fewer CT scans needed after cerebral bleeding
20.03.2019 | Universitätsspital Bern

nachricht Building blocks for new medications: the University of Graz is seeking a technology partner
19.03.2019 | Karl-Franzens-Universität Graz

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: The taming of the light screw

DESY and MPSD scientists create high-order harmonics from solids with controlled polarization states, taking advantage of both crystal symmetry and attosecond electronic dynamics. The newly demonstrated technique might find intriguing applications in petahertz electronics and for spectroscopic studies of novel quantum materials.

The nonlinear process of high-order harmonic generation (HHG) in gases is one of the cornerstones of attosecond science (an attosecond is a billionth of a...

Im Focus: Magnetic micro-boats

Nano- and microtechnology are promising candidates not only for medical applications such as drug delivery but also for the creation of little robots or flexible integrated sensors. Scientists from the Max Planck Institute for Polymer Research (MPI-P) have created magnetic microparticles, with a newly developed method, that could pave the way for building micro-motors or guiding drugs in the human body to a target, like a tumor. The preparation of such structures as well as their remote-control can be regulated using magnetic fields and therefore can find application in an array of domains.

The magnetic properties of a material control how this material responds to the presence of a magnetic field. Iron oxide is the main component of rust but also...

Im Focus: Self-healing coating made of corn starch makes small scratches disappear through heat

Due to the special arrangement of its molecules, a new coating made of corn starch is able to repair small scratches by itself through heat: The cross-linking via ring-shaped molecules makes the material mobile, so that it compensates for the scratches and these disappear again.

Superficial micro-scratches on the car body or on other high-gloss surfaces are harmless, but annoying. Especially in the luxury segment such surfaces are...

Im Focus: Stellar cartography

The Potsdam Echelle Polarimetric and Spectroscopic Instrument (PEPSI) at the Large Binocular Telescope (LBT) in Arizona released its first image of the surface magnetic field of another star. In a paper in the European journal Astronomy & Astrophysics, the PEPSI team presents a Zeeman- Doppler-Image of the surface of the magnetically active star II Pegasi.

A special technique allows astronomers to resolve the surfaces of faraway stars. Those are otherwise only seen as point sources, even in the largest telescopes...

Im Focus: Heading towards a tsunami of light

Researchers at Chalmers University of Technology and the University of Gothenburg, Sweden, have proposed a way to create a completely new source of radiation. Ultra-intense light pulses consist of the motion of a single wave and can be described as a tsunami of light. The strong wave can be used to study interactions between matter and light in a unique way. Their research is now published in the scientific journal Physical Review Letters.

"This source of radiation lets us look at reality through a new angle - it is like twisting a mirror and discovering something completely different," says...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

International Modelica Conference with 330 visitors from 21 countries at OTH Regensburg

11.03.2019 | Event News

Selection Completed: 580 Young Scientists from 88 Countries at the Lindau Nobel Laureate Meeting

01.03.2019 | Event News

LightMAT 2019 – 3rd International Conference on Light Materials – Science and Technology

28.02.2019 | Event News

 
Latest News

Laser processing is a matter for the head – LZH at the Hannover Messe 2019

25.03.2019 | Trade Fair News

A Varied Menu

25.03.2019 | Life Sciences

‘Time Machine’ heralds new era

25.03.2019 | Information Technology

VideoLinks
Science & Research
Overview of more VideoLinks >>>