Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

New source for heart bypass replacement blood vessels: Fibrin-based TEVs

09.11.2004


Fibrin gel matrix-based vessel ready for test transplantation after only two weeks in culture

The search for a stable, renewable source of blood vessels, especially for potential use in heart bypass surgery, has reached a milestone at the State University of New York at Buffalo. A multi-disciplinary team at SUNY Buffalo designed tissue engineered blood vessels (TEVs) using a matrix of vascular smooth muscle embedded in fibrin gels. After only two weeks in culture, the TEVs showed the strength and resiliency necessary for implantation. Even more exciting, 15 weeks after implantation, the fibrin-based TEVs "exhibited remarkable remodeling with considerable production of collagen and elastin, and significantly increased mechanical strength (and) physiological levels of blood flow and vasoreactivity," according to a paper published online in the American Journal of Physiology-Heart and Circulatory Physiology.

Currently, blood vessels are usually "harvested" from the patient’s own leg, often causing pain and discomfort, as well as extra surgical steps. So the need for a source of strong, yet elastic -- and physiologically responsive – replacement blood vessels has been the subject of laboratory searches and experimentation for decades.



The study, "Fibrin-based functional and implantable small diameter blood vessels," was written by Daniel D. Swartz and James A. Russell from the SUNY Buffalo Department of Physiology and Biophysics, and Stelios T. Andreadis of SUNY Buffalo’s Department of Chemical and Biological Engineering, Buffalo, New York.

Fibrin-based TEVs develop strength and reactivity after two weeks in culture

The researchers concluded that "fibrin-based TEVs hold significant promise for treatment of vascular disease and as a model system to address interesting questions with regards to blood vessel development and pathophysiology." Replacement of large (6-millimeter and larger) blood vessels has been successful using several synthetic materials, but smaller-diameter grafts usually failed due to thrombus or plaque formation. Various tissue-engineering approaches were developed using natural or synthetic biomaterials as scaffolds for cell growth. Biodegradable scaffolds using polyglycolic acid (PGA) have shown promise and collagen gels also worked, though 7mm collagen-based TEVs needed Dacron mesh reinforcement.

Prior to this study, the SUNY Buffalo researchers thought fibrin could be substituted for collagen as a scaffold for TEV because it shares high seeding efficiency (with smooth muscle cells, or SMCs) and uniform cell distribution. Indeed, in "contrast to collagen, fibrin stimulates synthesis of collagen and elastin and yields TEV constructs with improved mechanical properties, suggesting that fibrin may be a more appropriate scaffold for cardiovascular tissue engineering," they said.

In the current study, the SUNY Buffalo researchers took lamb vascular smooth muscle and endothelial cells to engineer small diameter (4mm) blood vessels, "which attained considerable mechanical strength and vasoractivity after only two weeks in culture." When the thrombin/fibrinogen solution was poured into the fibrin mold to start the process, it "gelled within 5-10 seconds." Tests using vasoactive receptor and nonreceptor substances showed that the fibrin-based TEVs exhibited an ability to expand and contract over time, similar to native vessels. This is a very important property that allows blood vessels to adapt to changes in blood flow rate.

Transplanted TEVs produce new collagen, elastin

Furthermore, after "a short time in culture, SMCs remodeled the extracellular matrix by substituting the fibrin gel with collagen." They found that after only about two weeks, the structure was ready for transplantation. "TEVs containing SMC and endothelial cells were implanted as interpositional grafts into the external jugular veins of 12-week-old lambs," Swartz et al. reported. "After implantation TEVs integrated very well with the cephalic and caudal ends of the jugular vein and remodeled successfully producing new collagen and elastin," they said. When the implants were removed after 15 weeks, there was no fibrin left; it had been completely replaced by collagen.

"Most importantly," the researchers wrote, fibrin-based "TEVs remained patent and demonstrated blood flow comparable with that of the control (natural, non-operated) jugular vein, suggesting that fibrin based blood vessels may provide a promising therapeutic modality and a good model system to study vascular development."

Next steps

According to Stelios Andreadis, the team is preparing to submit a grant application to the National Institutes of Health "to improve vessels’ mechanical strength." They will also seek to make the matrix stronger using recombinant DNA techniques and "engineer vessels from bone marrow-derived stem cells to provide a source of autologous cells for transplantation, and therefore avoid the use of native vessels as a cell source," Andreadis noted.

Mayer Resnick | EurekAlert!
Further information:
http://www.the-aps.org

More articles from Health and Medicine:

nachricht How prenatal maternal infections may affect genetic factors in Autism spectrum disorder
22.03.2017 | University of California - San Diego

nachricht Camouflage apples
22.03.2017 | Empa - Eidgenössische Materialprüfungs- und Forschungsanstalt

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: Giant Magnetic Fields in the Universe

Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.

The results will be published on March 22 in the journal „Astronomy & Astrophysics“.

Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...

Im Focus: Tracing down linear ubiquitination

Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.

Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...

Im Focus: Perovskite edges can be tuned for optoelectronic performance

Layered 2D material improves efficiency for solar cells and LEDs

In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...

Im Focus: Polymer-coated silicon nanosheets as alternative to graphene: A perfect team for nanoelectronics

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...

Im Focus: Researchers Imitate Molecular Crowding in Cells

Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to simulate these confined natural conditions in artificial vesicles for the first time. As reported in the academic journal Small, the results are offering better insight into the development of nanoreactors and artificial organelles.

Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

International Land Use Symposium ILUS 2017: Call for Abstracts and Registration open

20.03.2017 | Event News

CONNECT 2017: International congress on connective tissue

14.03.2017 | Event News

ICTM Conference: Turbine Construction between Big Data and Additive Manufacturing

07.03.2017 | Event News

 
Latest News

Pulverizing electronic waste is green, clean -- and cold

22.03.2017 | Materials Sciences

Astronomers hazard a ride in a 'drifting carousel' to understand pulsating stars

22.03.2017 | Physics and Astronomy

New gel-like coating beefs up the performance of lithium-sulfur batteries

22.03.2017 | Materials Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>