Navigation Links
In surprise finding, blood clots absorb bacterial toxin

Blood clots play an unexpected role in protecting the body from the deadly effects of bacteria by absorbing bacterial toxins, researchers at the University of California, Davis, have found. The research was published Dec. 2 in the journal PLOS ONE.

"It's a significant addition to the short list of defenses that animals use to protect themselves against toxin-induced sepsis," said Peter Armstrong, professor of molecular and cellular biology at UC Davis and senior author on the paper.

Even with modern antibiotics, septic shock from bacterial infections afflicts about 300,000 people a year in the U.S., with a mortality rate of 30 to 50 percent. Septic shock is caused by Gram-negative bacteria, which release a toxin called lipopolysaccharide or endotoxin. In small amounts, lipopolysaccharide triggers inflammation. When infections with these bacteria get out of hand, lipopolysaccharide courses through the bloodstream, causing catastrophic damage to organs and tissues.

These toxins cause disease in a variety of animal species lipopolysaccharide is also toxic to both horseshoe crabs and lobsters, separated from humans by hundreds of millions of years of evolution. In humans and other mammals, blood clots quickly form from a mix of specialized blood cells and protein fibers. Arthropods like horseshoe crabs and lobsters can also form clots in response to injury, with a different mix of cells and proteins.

Clots protect and help to seal wounds, prevent blood or body fluids from leaking out and form a physical barrier that entangles and blocks bacteria from entering the body. The new study shows that they also actively soak up lipopolysaccharide, reducing its release from the wound site into the body, where it could cause disease or even death.

Armstrong's laboratory had previously developed fluorescent labels to show that a lipopolysaccharide-like molecule is present in chloroplasts, structures inside cells of green plants that carry out photosynthesis and are thought to be descended from bacteria. As he also studies the role of blood clots in resisting infections, Armstrong decided to test the same techniques on blood clots that had been exposed to bacteria or to bacterial lipopolysaccharide. The fluorescent probes lit up the clots, showing that the clot fibers bound lipopolysaccharide to their surfaces.

"I was ecstatic," Armstrong said. "It was one of those moments that makes the rest of the slogging worthwhile."

Armstrong and colleagues Margaret Armstrong at UC Davis and Frederick Rickles at George Washington University looked at clots of blood, or its equivalent, from humans, mice, lobsters and horseshoe crabs. In all four species, they found that fluorescently tagged lipopolysaccharide was bound to the fibers of the blood clot. The toxin was too tightly attached to be readily removed by chemical treatments that remove weakly bound macromolecules from proteins.

During a sabbatical leave in the laboratory of Dr. Bruce Furie at Beth Deaconess Medical Center and Harvard University, Armstrong was also able to film clots in blood vessels of live mice and showed that these in vivo clots took up lipopolysaccharide in real time. These in vivo experiments, he said, confirm the bench-top observations and offer new insights into the pathology of sepsis.

One of the deadly consequences of septic shock is disseminated intravascular coagulation, when blood clots form rapidly throughout the body. But the new results suggest that on a small and local scale, this might be part of a protective mechanism against sepsis these intravascular clots can soak up quantities of lipopolysaccharide from the blood. They also show that rather than being a simple physical barrier, blood clots play an active and dynamic role in protecting the body from infections.

Parts of the research were carried out at the Woods Hole Marine Biological Laboratory. The work was funded by a grant from the National Science Foundation.


Contact: Andy Fell
University of California - Davis

Related biology news :

1. Stanford researchers surprised to find how neural circuits identify information needed for decisions
2. Surprises discovered in decoded kiwifruit genome
3. Family tree of fish yields surprises
4. Surprise finding reveals how adaptive our immune systems can be
5. Surprise species at risk from climate change
6. Science surprise: Toxic protein made in unusual way may explain brain disorder
7. Peru surprises with 2 new amazing species of woodlizards
8. EARTH: Antarctic trees surprise scientists
9. Diet of early human relative Australopithecus shows surprises, says Texas A&M researcher
10. An evolutionary surprise
11. New method for stabilizing hemoglobin could lead to stable vaccines, artificial blood
Post Your Comments:
(Date:11/12/2015)... golden retriever that stayed healthy despite having the gene ... new lead for treating this muscle-wasting disorder, report scientists ... and Harvard and the University of São Paolo in ... pinpoints a protective gene that boosts muscle regeneration, ... Children,s lab of Lou Kunkel , PhD, is ...
(Date:11/10/2015)... Nov. 10, 2015 About ... that helps to identify and verify the identity ... considered as the secure and accurate method of ... a particular individual because each individual,s signature is ... especially when dynamic signature of an individual is ...
(Date:10/29/2015)... Oct. 29, 2015   MedNet Solutions , an ... spectrum of clinical research, is pleased to announce that ... Association (MHTA) as one of only three finalists for ... – Small and Growing" category. The Tekne Awards honor ... shown superior technology innovation and leadership. ...
Breaking Biology News(10 mins):
(Date:11/25/2015)... and HOLLISTON, Mass. , Nov. 25, ... HART ), a biotechnology company developing bioengineered organ ... Jim McGorry will present at the LD Micro ... at 2:30 p.m. PT. The presentation will be webcast ... days. Management will also be available at the conference ...
(Date:11/25/2015)... Orexigen® Therapeutics, Inc. (Nasdaq: OREX ) ... chat discussion at the Piper Jaffray 27th Annual Healthcare ... discussion is scheduled for Wednesday, December 2, at 8:00 ... replay will be available for 14 days after the ... NormartVP, Corporate Communications and Business Development , BrewLife(858) 875-8629 ...
(Date:11/24/2015)... ... November 24, 2015 , ... The United States Golf Association (USGA) today announced ... Section Award. Presented annually since 1961, the USGA Green Section Award recognizes an individual’s ... , Clarke, of Iselin, N.J., is an extension specialist of turfgrass pathology ...
(Date:11/24/2015)... ... November 24, 2015 , ... Copper is an essential ... bound to proteins, copper is also toxic to cells. With a $1.3 million ... (WPI) will conduct a systematic study of copper in the bacteria Pseudomonas aeruginosa ...
Breaking Biology Technology: