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 Inselspital: Fewer CT scans needed after cerebral bleeding
20.03.2019 | Universitätsspital Bern

nachricht Building blocks for new medications: the University of Graz is seeking a technology partner
19.03.2019 | Karl-Franzens-Universität Graz

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: The taming of the light screw

DESY and MPSD scientists create high-order harmonics from solids with controlled polarization states, taking advantage of both crystal symmetry and attosecond electronic dynamics. The newly demonstrated technique might find intriguing applications in petahertz electronics and for spectroscopic studies of novel quantum materials.

The nonlinear process of high-order harmonic generation (HHG) in gases is one of the cornerstones of attosecond science (an attosecond is a billionth of a...

Im Focus: Magnetic micro-boats

Nano- and microtechnology are promising candidates not only for medical applications such as drug delivery but also for the creation of little robots or flexible integrated sensors. Scientists from the Max Planck Institute for Polymer Research (MPI-P) have created magnetic microparticles, with a newly developed method, that could pave the way for building micro-motors or guiding drugs in the human body to a target, like a tumor. The preparation of such structures as well as their remote-control can be regulated using magnetic fields and therefore can find application in an array of domains.

The magnetic properties of a material control how this material responds to the presence of a magnetic field. Iron oxide is the main component of rust but also...

Im Focus: Self-healing coating made of corn starch makes small scratches disappear through heat

Due to the special arrangement of its molecules, a new coating made of corn starch is able to repair small scratches by itself through heat: The cross-linking via ring-shaped molecules makes the material mobile, so that it compensates for the scratches and these disappear again.

Superficial micro-scratches on the car body or on other high-gloss surfaces are harmless, but annoying. Especially in the luxury segment such surfaces are...

Im Focus: Stellar cartography

The Potsdam Echelle Polarimetric and Spectroscopic Instrument (PEPSI) at the Large Binocular Telescope (LBT) in Arizona released its first image of the surface magnetic field of another star. In a paper in the European journal Astronomy & Astrophysics, the PEPSI team presents a Zeeman- Doppler-Image of the surface of the magnetically active star II Pegasi.

A special technique allows astronomers to resolve the surfaces of faraway stars. Those are otherwise only seen as point sources, even in the largest telescopes...

Im Focus: Heading towards a tsunami of light

Researchers at Chalmers University of Technology and the University of Gothenburg, Sweden, have proposed a way to create a completely new source of radiation. Ultra-intense light pulses consist of the motion of a single wave and can be described as a tsunami of light. The strong wave can be used to study interactions between matter and light in a unique way. Their research is now published in the scientific journal Physical Review Letters.

"This source of radiation lets us look at reality through a new angle - it is like twisting a mirror and discovering something completely different," says...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

International Modelica Conference with 330 visitors from 21 countries at OTH Regensburg

11.03.2019 | Event News

Selection Completed: 580 Young Scientists from 88 Countries at the Lindau Nobel Laureate Meeting

01.03.2019 | Event News

LightMAT 2019 – 3rd International Conference on Light Materials – Science and Technology

28.02.2019 | Event News

 
Latest News

Solving the efficiency of Gram-negative bacteria

22.03.2019 | Life Sciences

Bacteria bide their time when antibiotics attack

22.03.2019 | Life Sciences

Open source software helps researchers extract key insights from huge sensor datasets

22.03.2019 | Information Technology

VideoLinks
Science & Research
Overview of more VideoLinks >>>