Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Engineered blood vessels prove durable and clot resistant

18.11.2002


American Heart Association meeting report



Researchers have built mechanically sound blood vessels out of tissue from human skin cells, according to a study reported today at the American Heart Association’s Scientific Sessions 2002. The technique involves tissue engineering, an emerging science that takes cells from the body, manipulates them in the laboratory to create functional tissue, and puts the new tissue back into the patient.

The goal is to produce healthy, functioning blood vessels built exclusively from a person’s own cells, so the body’s immune system won’t reject the new tissue. Such vessels would be important in heart and leg bypass operations and for vessels called arteriovenous shunts used for dialysis patients.


The scientists reported that tissue-engineered blood vessels didn’t burst or develop blood clots in laboratory tests and short-term animal experiments.

"The study’s most important findings were: First, the technology works from a commercial perspective, meaning we can build mechanically sound vessels for a wide array of patients using the exact same protocol," says Todd McAllister, Ph.D., president and chief executive officer of Cytograft Tissue Engineering in Novato, Calif., which developed the vessel-building technique.

"Second, we demonstrated that thrombogenesis (the formation of blood clots) does not appear to be a problem in the short term – up to 14 days. Short-term blood clots are the biggest challenge facing most synthetic materials, whether they are used for blood vessels, new heart valves, or other vascular prostheses. We expect to begin this research in humans within 18 months."

In the study reported today, researchers took fibroblast cells from 11 patients (ages 54 to 84) with advanced cardiovascular disease who had coronary artery bypass operations at Stanford University. Fibroblasts form the outer wall of blood vessels. The researchers used endothelial cells from animals to make the inner lining of the vessels.

Typically, tissue engineering involves growing cells on a synthetic scaffold to create a specific shape, such as a piece of bone for use in facial reconstruction surgery. These scaffolds have traditionally been necessary to provide mechanical strength to the new tissue.

However, Cytograft’s chief scientific officer Nicolas L’Heureux, Ph.D., has developed a different approach called sheet-based tissue engineering.

"We can build a tissue that is only a few hundred microns thick, the diameter of several human hairs, that is robust enough that we don’t need synthetic materials or scaffolding to support it," L’Heureux says. The cell sheets are removed from the dish and wrapped around a temporary stainless steel cylinder 4 millimeters (0.15 inch) in diameter. The vessel then goes through a maturation phase where the separate layers fuse into a homogeneous tissue.

After removing the tissue from the steel cylinder, endothelial cells are seeded to the inside to create the inner lining of the blood vessel. Finally, the vessels are exposed to increasing rates of fluid flow and pressure to precondition them for implantation.

The engineered vessels were implanted as a femoral (leg) artery graft in study animals. The vessels were then removed at three, seven and 14 days after implantation. All but two of the vessels survived past day three and seemed mechanically stable without forming blood clots.

One question they had going into this study is whether the same chemicals and techniques that could successfully engineer tissue cells from one human into a new blood vessel would also work on cells from other humans.

"It was quite conceivable that differences from patient to patient would be so significant that the same recipe for making blood vessels could not be used in all cases," McAllister says. "We had no idea whether we could do this across a wide range of age- and risk-matched patients."

With early evidence showing the vessels’ reliability and clot resistance, researchers plan to implant tissue-engineered blood vessels in humans in 12 to 18 months, he says. The first patients will be those with peripheral vascular disease, the severe blockage of a leg artery that can lead to amputation.


Co-authors are Mark Koransky, M.D.; Nathalie Dusserre, Ph.D.; Gerhardt Konig, B.S.; and Robert Robbins, M.D. Abstract 1864

Carole Bullock | EurekAlert!
Further information:
http://www.americanheart.org/

More articles from Health and Medicine:

nachricht Plasmonic biosensors enable development of new easy-to-use health tests
14.12.2017 | Aalto University

nachricht ASU scientists develop new, rapid pipeline for antimicrobials
14.12.2017 | Arizona State University

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: Long-lived storage of a photonic qubit for worldwide teleportation

MPQ scientists achieve long storage times for photonic quantum bits which break the lower bound for direct teleportation in a global quantum network.

Concerning the development of quantum memories for the realization of global quantum networks, scientists of the Quantum Dynamics Division led by Professor...

Im Focus: Electromagnetic water cloak eliminates drag and wake

Detailed calculations show water cloaks are feasible with today's technology

Researchers have developed a water cloaking concept based on electromagnetic forces that could eliminate an object's wake, greatly reducing its drag while...

Im Focus: Scientists channel graphene to understand filtration and ion transport into cells

Tiny pores at a cell's entryway act as miniature bouncers, letting in some electrically charged atoms--ions--but blocking others. Operating as exquisitely sensitive filters, these "ion channels" play a critical role in biological functions such as muscle contraction and the firing of brain cells.

To rapidly transport the right ions through the cell membrane, the tiny channels rely on a complex interplay between the ions and surrounding molecules,...

Im Focus: Towards data storage at the single molecule level

The miniaturization of the current technology of storage media is hindered by fundamental limits of quantum mechanics. A new approach consists in using so-called spin-crossover molecules as the smallest possible storage unit. Similar to normal hard drives, these special molecules can save information via their magnetic state. A research team from Kiel University has now managed to successfully place a new class of spin-crossover molecules onto a surface and to improve the molecule’s storage capacity. The storage density of conventional hard drives could therefore theoretically be increased by more than one hundred fold. The study has been published in the scientific journal Nano Letters.

Over the past few years, the building blocks of storage media have gotten ever smaller. But further miniaturization of the current technology is hindered by...

Im Focus: Successful Mechanical Testing of Nanowires

With innovative experiments, researchers at the Helmholtz-Zentrums Geesthacht and the Technical University Hamburg unravel why tiny metallic structures are extremely strong

Light-weight and simultaneously strong – porous metallic nanomaterials promise interesting applications as, for instance, for future aeroplanes with enhanced...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

See, understand and experience the work of the future

11.12.2017 | Event News

Innovative strategies to tackle parasitic worms

08.12.2017 | Event News

AKL’18: The opportunities and challenges of digitalization in the laser industry

07.12.2017 | Event News

 
Latest News

Plasmonic biosensors enable development of new easy-to-use health tests

14.12.2017 | Health and Medicine

New type of smart windows use liquid to switch from clear to reflective

14.12.2017 | Physics and Astronomy

BigH1 -- The key histone for male fertility

14.12.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>