Featured Research

from universities, journals, and other organizations

How Life-threatening Blood Clots Take Hold

Date:
April 17, 2009
Source:
Cell Press
Summary:
When plaques coating blood vessel walls rupture and expose collagen, platelets spring into action to form a blood clot at the damaged site. Now scientists reveal how those life-threatening clots -- a leading cause of death in the United States, Europe and other industrialized countries -- get an early grip. The discovery might offer a new way to fight clot formation before it can even begin, according to the researchers.

When plaques coating blood vessel walls rupture and expose collagen, platelets spring into action to form a blood clot at the damaged site. Now, a new report in the April 17th issue of the journal Cell reveals how those life-threatening clots—a leading cause of death in the United States, Europe and other industrialized countries--get an early grip. The discovery might offer a new way to fight clot formation before it can even begin, according to the researchers.

"Compared to other diseases, blood clotting has been very well understood," said Athan Kuliopulos of Tufts Medical Center and Tufts University School of Medicine. Nevertheless, he continued, many people still suffer from heart attacks, ischemic stroke and death as a result of clot formation.

"Drugs designed to inhibit clots through known pathways are widely used by millions. They work well, but not perfectly. There is still an unmet need." Those drugs include aspirin and the so-called thienopyridines, including Clopidogrel (trade name Plavix).

Scientists have known that a protein called thrombin plays an important role in clot formation as a potent activator of platelets. It also cuts fibrinogen into fibrin, a fibrous protein that works together with platelets to form a clot.

But thrombin isn't the whole story. Enzymes known as matrix metalloproteases have recently emerged as important players in platelet function and the biology of blood vessels. Two of those enzymes, MMP-1 and MMP-2 can actually encourage platelet activation, according to earlier studies, although the means were unknown. In cancer cells too, MMP-1 activates a receptor known as PAR1 – the same receptor that is also responsible for receiving the thrombin signal on human platelets.

"There is abundant proMMP-1 coating platelets," Kuliopulos said. "We thought maybe it was on the outside waiting to be activated by something. Maybe it could be involved in an early event in blood clotting, before thrombin is around."

Indeed, Kuliopulos' team has now connected those dots. They show that exposure of platelets to collagen activates MMP-1, which in turn directly cut PAR1 on the surface of platelets. Collagen is the first thing a platelet "sees" when a blood vessel ruptures or is cut.

The MMP-1-PAR1 pathway activates another set of molecular players known to be involved in early clot formation, he said. Those activated platelets change their shape, sending out spikes and membrane sheets. "Within seconds, they become more sticky," adhering to the vessel surface and then other platelets.

Moreover, they show that treatments that block the MMP1-PAR1 pathway prevent blood clots from forming in the presence of collagen, suggesting that drugs targeting this metalloprotease-receptor system could offer a new way to treat patients with acute coronary syndromes.

According to the new results, PAR1 inhibitors already being tested in clinical trials might have an added benefit, Kuliopulos said. It's also possible they might work a little too well, since there is a careful balance between the risk of dangerous blood clots and the risk of bleeding. "An MMP-1 inhibitor might be better tolerated," he said.

The researchers include Vishal Trivedi, Adrienne Boire, Boris Tchernychev, Nicole C. Kaneider, Andrew J. Leger, Katie O'Callaghan, Lidija Covic, and Athan Kuliopulos, of Tufts University School of Medicine, Molecular Oncology Research Institute, Tufts Medical Center, Boston, MA.


Story Source:

The above story is based on materials provided by Cell Press. Note: Materials may be edited for content and length.


Cite This Page:

Cell Press. "How Life-threatening Blood Clots Take Hold." ScienceDaily. ScienceDaily, 17 April 2009. <www.sciencedaily.com/releases/2009/04/090416125201.htm>.
Cell Press. (2009, April 17). How Life-threatening Blood Clots Take Hold. ScienceDaily. Retrieved July 29, 2014 from www.sciencedaily.com/releases/2009/04/090416125201.htm
Cell Press. "How Life-threatening Blood Clots Take Hold." ScienceDaily. www.sciencedaily.com/releases/2009/04/090416125201.htm (accessed July 29, 2014).

Share This




More Health & Medicine News

Tuesday, July 29, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Deadly Ebola Virus Threatens West Africa

Deadly Ebola Virus Threatens West Africa

AP (July 28, 2014) West African nations and international health organizations are working to contain the largest Ebola outbreak in history. It's one of the deadliest diseases known to man, but the CDC says it's unlikely to spread in the U.S. (July 28) Video provided by AP
Powered by NewsLook.com
$15B Deal on Vets' Health Care Reached

$15B Deal on Vets' Health Care Reached

AP (July 28, 2014) A bipartisan deal to improve veterans health care would authorize at least $15 billion in emergency spending to fix a veterans program scandalized by long patient wait times and falsified records. (July 28) Video provided by AP
Powered by NewsLook.com
Two Americans Contract Ebola in Liberia

Two Americans Contract Ebola in Liberia

Reuters - US Online Video (July 28, 2014) Two American aid workers in Liberia test positive for Ebola while working to combat the deadliest outbreak of the virus ever. Linda So reports. Video provided by Reuters
Powered by NewsLook.com
Traditional African Dishes Teach Healthy Eating

Traditional African Dishes Teach Healthy Eating

AP (July 28, 2014) Classes are being offered nationwide to encourage African Americans to learn about cooking fresh foods based on traditional African cuisine. The program is trying to combat obesity, heart disease and other ailments often linked to diet. (July 28) Video provided by AP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins