Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Exploring the molecular origin of blood clot flexibility

17.01.2007
Well-known protein structure acts as a molecular spring

How do blood clots maintain that precise balance of stiffness for wound healing and flexibility to go with the flow? Researchers at the University of Pennsylvania School of Medicine and the School of Arts and Sciences have shown that a well-known protein structure acts as a molecular spring, explaining one way that clots may stretch and bend under such physical stresses as blood flow.

They report their findings in a Letter in the latest online edition of the Biophysical Journal. This knowledge will inform researchers about clot physiology in such conditions as wound healing, stroke, and cardiovascular disease.

Clots are a three-dimensional network of fibers, made up primarily of the blood protein fibrinogen, which is converted to fibrin during clotting. A blood clot needs to have the right degree of stiffness and plasticity to stem the flow of blood when tissue is damaged, yet be flexible enough so that it does not block blood flow and cause heart attacks and strokes.

... more about:
»Fibrin »Fibrinogen »stiff

In previous research, senior author John W. Weisel, PhD, Professor of Cell and Developmental Biology, measured the elastic properties of individual fibers and found that the fibers, which are long and very thin, bend much more easily than they stretch, suggesting that clots deform in flowing blood or under other stresses, primarily by the bending of their fibers.

The current research extends those earlier findings to the molecular level, suggesting a way that individual fibers flex - by the unraveling of the three, tightly twisted rod-like regions within fibrinogen molecules, called alpha-helical coiled-coils. The researchers measured this change by pulling engineered strands of fibrinogen molecules using an atomic force microscope. This alpha-helical coiled-coil "spring" is a common motif in protein structure, first identified more than 50 years ago and so its stretchiness may have broader implications in biology and medicine.

By understanding mechanical processes at the molecular level, it may eventually be possible to see how they relate to the mechanical properties of single fibers and a whole clot. This knowledge may enable researchers to make predictions about the function of differently formed fibrin clots in the circulating blood or in a wound. For example, when clots are not stiff enough, problems with bleeding arise, and when clots are too stiff, there may be problems with thrombosis, which results when clots block the flow of blood. First author André Brown, a physics graduate student at Penn, notes that this research is a first step towards understanding the mechanics of the relationship between clot elasticity and disease.

Recent research by other scientists showed that a fibrin fiber could stretch four to five times its original length before snapping. "This is among the most extensible, or stretchy, of polymers that anyone has ever found," says Weisel. "But, how is the stretching happening at a molecular level? We think part of it has to be the unfolding of certain parts of the fibrin molecule, otherwise how can it stretch so much?"

Previous research from senior coauthor Dennis Discher, PhD, Professor in the Physics and Cell & Molecular Biology graduate groups, suggested the possibility that alpha-helical structures in some blood-cell proteins unfold at low levels of mechanical force. But "it wasn't known before that the coiled coil region of the fibrinogen molecule would be the part to unfold under the stress induced by the atomic force microscope," notes Brown.

Once the origins of the mechanical properties of clots are well understood, it may be possible to modulate those properties, note the study authors. "If we can change a certain parameter perhaps we can make a clot that's more or less stiff," explains Weisel. For example, various peptides or proteins, such as antibodies, bind specifically to fibrin, affecting clot structure. The idea would be to use such compounds in people to alter the properties of the clot, so it can be less obstructive and more easily dissolved.

In the future, the researchers will examine other processes at the molecular and fiber levels that may be responsible for the mechanical properties of clots to eventually develop a model that can then be used to predict the effect of changes at one scale on clot properties at other scales. Such a model should be useful for developing prophylactic and therapeutic treatments for many aspects of cardiovascular disease and stroke, suggest the investigators.

Karen Kreeger | EurekAlert!
Further information:
http://www.uphs.upenn.edu

Further reports about: Fibrin Fibrinogen stiff

More articles from Life Sciences:

nachricht Scientists uncover the role of a protein in production & survival of myelin-forming cells
19.07.2018 | Advanced Science Research Center, GC/CUNY

nachricht NYSCF researchers develop novel bioengineering technique for personalized bone grafts
18.07.2018 | New York Stem Cell Foundation

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Future electronic components to be printed like newspapers

A new manufacturing technique uses a process similar to newspaper printing to form smoother and more flexible metals for making ultrafast electronic devices.

The low-cost process, developed by Purdue University researchers, combines tools already used in industry for manufacturing metals on a large scale, but uses...

Im Focus: First evidence on the source of extragalactic particles

For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.

To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...

Im Focus: Magnetic vortices: Two independent magnetic skyrmion phases discovered in a single material

For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.

Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...

Im Focus: Breaking the bond: To take part or not?

Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.

A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...

Im Focus: New 2D Spectroscopy Methods

Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.

"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Leading experts in Diabetes, Metabolism and Biomedical Engineering discuss Precision Medicine

13.07.2018 | Event News

Conference on Laser Polishing – LaP: Fine Tuning for Surfaces

12.07.2018 | Event News

11th European Wood-based Panel Symposium 2018: Meeting point for the wood-based materials industry

03.07.2018 | Event News

 
Latest News

A smart safe rechargeable zinc ion battery based on sol-gel transition electrolytes

20.07.2018 | Power and Electrical Engineering

Reversing cause and effect is no trouble for quantum computers

20.07.2018 | Information Technology

Princeton-UPenn research team finds physics treasure hidden in a wallpaper pattern

20.07.2018 | Materials Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>