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 Correct connections are crucial
26.06.2017 | Charité - Universitätsmedizin Berlin

nachricht One gene closer to regenerative therapy for muscular disorders
01.06.2017 | Cincinnati Children's Hospital 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: Can we see monkeys from space? Emerging technologies to map biodiversity

An international team of scientists has proposed a new multi-disciplinary approach in which an array of new technologies will allow us to map biodiversity and the risks that wildlife is facing at the scale of whole landscapes. The findings are published in Nature Ecology and Evolution. This international research is led by the Kunming Institute of Zoology from China, University of East Anglia, University of Leicester and the Leibniz Institute for Zoo and Wildlife Research.

Using a combination of satellite and ground data, the team proposes that it is now possible to map biodiversity with an accuracy that has not been previously...

Im Focus: Climate satellite: Tracking methane with robust laser technology

Heatwaves in the Arctic, longer periods of vegetation in Europe, severe floods in West Africa – starting in 2021, scientists want to explore the emissions of the greenhouse gas methane with the German-French satellite MERLIN. This is made possible by a new robust laser system of the Fraunhofer Institute for Laser Technology ILT in Aachen, which achieves unprecedented measurement accuracy.

Methane is primarily the result of the decomposition of organic matter. The gas has a 25 times greater warming potential than carbon dioxide, but is not as...

Im Focus: How protons move through a fuel cell

Hydrogen is regarded as the energy source of the future: It is produced with solar power and can be used to generate heat and electricity in fuel cells. Empa researchers have now succeeded in decoding the movement of hydrogen ions in crystals – a key step towards more efficient energy conversion in the hydrogen industry of tomorrow.

As charge carriers, electrons and ions play the leading role in electrochemical energy storage devices and converters such as batteries and fuel cells. Proton...

Im Focus: A unique data centre for cosmological simulations

Scientists from the Excellence Cluster Universe at the Ludwig-Maximilians-Universität Munich have establised "Cosmowebportal", a unique data centre for cosmological simulations located at the Leibniz Supercomputing Centre (LRZ) of the Bavarian Academy of Sciences. The complete results of a series of large hydrodynamical cosmological simulations are available, with data volumes typically exceeding several hundred terabytes. Scientists worldwide can interactively explore these complex simulations via a web interface and directly access the results.

With current telescopes, scientists can observe our Universe’s galaxies and galaxy clusters and their distribution along an invisible cosmic web. From the...

Im Focus: Scientists develop molecular thermometer for contactless measurement using infrared light

Temperature measurements possible even on the smallest scale / Molecular ruby for use in material sciences, biology, and medicine

Chemists at Johannes Gutenberg University Mainz (JGU) in cooperation with researchers of the German Federal Institute for Materials Research and Testing (BAM)...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Plants are networkers

19.06.2017 | Event News

Digital Survival Training for Executives

13.06.2017 | Event News

Global Learning Council Summit 2017

13.06.2017 | Event News

 
Latest News

Touch Displays WAY-AX and WAY-DX by WayCon

27.06.2017 | Power and Electrical Engineering

Drones that drive

27.06.2017 | Information Technology

Ultra-compact phase modulators based on graphene plasmons

27.06.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>