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 Correct connections are crucial
26.06.2017 | Charité - Universitätsmedizin Berlin

nachricht One gene closer to regenerative therapy for muscular disorders
01.06.2017 | Cincinnati Children's Hospital Medical Center

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: Can we see monkeys from space? Emerging technologies to map biodiversity

An international team of scientists has proposed a new multi-disciplinary approach in which an array of new technologies will allow us to map biodiversity and the risks that wildlife is facing at the scale of whole landscapes. The findings are published in Nature Ecology and Evolution. This international research is led by the Kunming Institute of Zoology from China, University of East Anglia, University of Leicester and the Leibniz Institute for Zoo and Wildlife Research.

Using a combination of satellite and ground data, the team proposes that it is now possible to map biodiversity with an accuracy that has not been previously...

Im Focus: Climate satellite: Tracking methane with robust laser technology

Heatwaves in the Arctic, longer periods of vegetation in Europe, severe floods in West Africa – starting in 2021, scientists want to explore the emissions of the greenhouse gas methane with the German-French satellite MERLIN. This is made possible by a new robust laser system of the Fraunhofer Institute for Laser Technology ILT in Aachen, which achieves unprecedented measurement accuracy.

Methane is primarily the result of the decomposition of organic matter. The gas has a 25 times greater warming potential than carbon dioxide, but is not as...

Im Focus: How protons move through a fuel cell

Hydrogen is regarded as the energy source of the future: It is produced with solar power and can be used to generate heat and electricity in fuel cells. Empa researchers have now succeeded in decoding the movement of hydrogen ions in crystals – a key step towards more efficient energy conversion in the hydrogen industry of tomorrow.

As charge carriers, electrons and ions play the leading role in electrochemical energy storage devices and converters such as batteries and fuel cells. Proton...

Im Focus: A unique data centre for cosmological simulations

Scientists from the Excellence Cluster Universe at the Ludwig-Maximilians-Universität Munich have establised "Cosmowebportal", a unique data centre for cosmological simulations located at the Leibniz Supercomputing Centre (LRZ) of the Bavarian Academy of Sciences. The complete results of a series of large hydrodynamical cosmological simulations are available, with data volumes typically exceeding several hundred terabytes. Scientists worldwide can interactively explore these complex simulations via a web interface and directly access the results.

With current telescopes, scientists can observe our Universe’s galaxies and galaxy clusters and their distribution along an invisible cosmic web. From the...

Im Focus: Scientists develop molecular thermometer for contactless measurement using infrared light

Temperature measurements possible even on the smallest scale / Molecular ruby for use in material sciences, biology, and medicine

Chemists at Johannes Gutenberg University Mainz (JGU) in cooperation with researchers of the German Federal Institute for Materials Research and Testing (BAM)...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Plants are networkers

19.06.2017 | Event News

Digital Survival Training for Executives

13.06.2017 | Event News

Global Learning Council Summit 2017

13.06.2017 | Event News

 
Latest News

Touch Displays WAY-AX and WAY-DX by WayCon

27.06.2017 | Power and Electrical Engineering

Drones that drive

27.06.2017 | Information Technology

Ultra-compact phase modulators based on graphene plasmons

27.06.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>