Featured Research

from universities, journals, and other organizations

Fighting infections with blood clots

Date:
August 4, 2010
Source:
Ludwig-Maximilians-Universität München
Summary:
Clot formation within small blood vessels helps in the fight against pathogenic microbes, researchers in Germany have shown. At the molecular level, clot formation turns out to be intimately connected with the innate immune system, a finding that may open up new therapeutic possibilities.

A research team at Ludwig-Maximilians-Universitaet in Munich has shown that clot formation within small blood vessels helps in the fight against pathogenic microbes. At the molecular level, clot formation turns out to be intimately connected with the innate immune system, a finding that may open up new therapeutic possibilities.

The adaptive immune system can recognize and respond specifically to particular infectious agents. But the first line of defence against pathogens is the so-called innate immune system. This system reacts to invaders by initiating unspecific inflammatory responses which attract various types of specialized cells such as neutrophils to the site of the incursion.

"Neutrophils secrete proteins that inactivate bacteria and other microbes," says LMU researcher Professor Bernd Engelmann, "but they also play a role in blood coagulation."

A research team led by Engelmann has now shown that the processes of blood coagulation and antimicrobial defence are functionally coupled -- and that neutrophils provide an important link between them. "During systemic infections neutrophils induce the formation of harmless clots in small blood vessels, which inhibits the dissemination of pathogens," says Engelmann. "Taken together, our results suggest that clot formation inside blood vessels is a part of the normal physiological response to pathogens. Hence there is also a physiological form of thrombosis. However, when clot formation is erroneously induced, in the absence of pathogens and within the larger blood vessels, then there is a high risk of heart attack or stroke. Our findings may provide new insights into the mechanisms responsible for pathological thrombosis, and suggest new ways of preventing them."

The results are published in the journal Nature Medicine.

The arthropods, which include insects and spiders, are the most species-rich division of the animal kingdom. All arthropods have in common that they are dependent on their innate immune system for protection against infections. This system mobilizes a rather unspecific set of defences, and reacts to attack by inducing inflammation at the site of infection. As part of this reaction, clots can form in the haemolymph that bathes the tissues and cells, effectively trapping invading cells and preventing the establishment of a systemic infection. Humans, like all other mammals, also have an innate immune system that reacts rapidly to invaders. It therefore seemed possible that a connection between blood coagulation and antimicrobial responses existed in humans as well

Researchers led by Professor Bernd Engelmann of the Institute of Clinical Chemistry at LMU Munich and Professor Steffen Massberg of the Technical University of Munich have just published a study in which they took a close look at the role of neutrophils in the innate immune system. Together with the circulating cells known as platelets, neutrophils accumulate rapidly at wound sites, which potentially provide portals of entry for pathogens. "The neutrophils produce antimicrobial factors, but they also play a role in blood coagulation," says Engelmann. "We suspected that this dual function has been conserved during evolution, and that neutrophils could serve as a functional link between blood clotting and antimicrobial defence."

The study revealed that some of the antimicrobial proteins secreted by neutrophils, in particular so-called serine proteases, also participate in the process of blood coagulation, and so facilitate the formation of clots in the blood vessels. In a systemic infection, when the invader has gained entry into the bloodstream and threatens the whole organism, bacterial pathogens were found to be trapped in tiny clots in small blood vessels in the liver, where the thrombi presumably cause no damage. But the new work showed that they effectively prevent the microbes from penetrating into the surrounding tissue. "Overall, our findings suggest that clot formation can be a physiological weapon that helps to fight off pathogenic microbes," says Engelmann. "Indeed, activation of the blood coagulation process is probably an important and widespread antimicrobial defence mechanism."

The process becomes problematical only when it contributes to the formation of clots in large blood vessels. "Thromboses are the most important cause of heart attack, stroke and pulmonary embolism, but they are also involved in the life-threatening long-term effects of sepsis and many types of infection," says Engelmann. "Arterial thrombosis, which can result from various pathologies, is actually one of the leading causes of death worldwide." Hence the new results could be useful in the search for new therapeutic strategies. "They do, after all, demonstrate that the same molecular mechanisms underlie the formation of both physiological and pathological forms of thrombosis, and they may point to new targets for treatment of the latter."


Story Source:

The above story is based on materials provided by Ludwig-Maximilians-Universität München. Note: Materials may be edited for content and length.


Journal Reference:

  1. Steffen Massberg, Lenka Grahl, Marie-Luise Von Bruehl, Davit Manukyan, Susanne Pfeiler, Christian Goosmann, Volker Brinkmann, Michael Lorenz, Kiril Bidzhekov, Avinash B Khandagale, Ildiko Konrad, Elisabeth Kennerknecht, Katja Reges, Stefan Holdenrieder, Siegmund Braun, Christoph Reinhardt, Michael Spannagl, Klaus T Preissner, Bernd Engelmann. Reciprocal coupling of coagulation and innate immunity via neutrophil serine proteases. Nature Medicine, 2010; DOI: 10.1038/nm.2184

Cite This Page:

Ludwig-Maximilians-Universität München. "Fighting infections with blood clots." ScienceDaily. ScienceDaily, 4 August 2010. <www.sciencedaily.com/releases/2010/08/100803101920.htm>.
Ludwig-Maximilians-Universität München. (2010, August 4). Fighting infections with blood clots. ScienceDaily. Retrieved September 2, 2014 from www.sciencedaily.com/releases/2010/08/100803101920.htm
Ludwig-Maximilians-Universität München. "Fighting infections with blood clots." ScienceDaily. www.sciencedaily.com/releases/2010/08/100803101920.htm (accessed September 2, 2014).

Share This




More Health & Medicine News

Tuesday, September 2, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

U.N. Says Ebola Travel Restrictions Will Cause Food Shortage

U.N. Says Ebola Travel Restrictions Will Cause Food Shortage

Newsy (Sep. 2, 2014) — The U.N. says the problem is two-fold — quarantine zones and travel restrictions are limiting the movement of both people and food. Video provided by Newsy
Powered by NewsLook.com
Get on Your Bike! London Cycling Popularity Soars Despite Danger

Get on Your Bike! London Cycling Popularity Soars Despite Danger

AFP (Sep. 1, 2014) — Wedged between buses, lorries and cars, cycling in London isn't for the faint hearted. Nevertheless the number of people choosing to bike in the British capital has doubled over the past 15 years. Duration: 02:27 Video provided by AFP
Powered by NewsLook.com
Can You Train Your Brain To Eat Healthy?

Can You Train Your Brain To Eat Healthy?

Newsy (Sep. 1, 2014) — New research says if you condition yourself to eat healthy foods, eventually you'll crave them instead of junk food. Video provided by Newsy
Powered by NewsLook.com
We've Got Mites Living In Our Faces And So Do You

We've Got Mites Living In Our Faces And So Do You

Newsy (Aug. 30, 2014) — A new study suggests 100 percent of adult humans (those over 18 years of age) have Demodex mites living in their faces. Video provided by Newsy
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