Bioengineered Blood Vessels May Revolutionize Bypass & Hemodialysis Surgeries
A new bioengineering technique for creating 'off the shelf' blood vessels was unveiled today in the journal Science Translational Medicine. Researchers believe their technique might one day obviate the need to use the patient's own blood vessels to replace those that are not functioning, specifically in heart by-pass and hemodialysis surgeries, saving as many as 500,000 lives a year in the U.S. alone.
Humacyte Inc., the biomedical company that has been working on this technique for 15 years, led the study. Participating researchers from Duke University Medical Center, Yale University, and East Carolina University were also involved.
The bioengineered blood vessels were grown from cadaver muscle tissue on a synthetic scaffold made from material (polyglycolic acid) similar to that used for dissolvable stitches. Once placed on the scaffold, the cells eventually released proteins, mostly collagen, which grew around the scaffold as the scaffold dissolved.
The scaffolds, now tubes, were tested to see if they could withstand the pressure of blood passing through them by with the pressure of another liquid. Then the artificial veins were flushed out with detergents to insure that no living cells that could be rejected by a recipient were remaining.
The bioengineered veins were then stored for a year, after which they proved to be as smooth, resilient, and strong as they had before.
Muscle cells for the replacement veins were taken from humans and dogs. The 'veins' initiated with human cells were tested in baboon models for 'arterivenous access of hemodialysis.' Those initiated with dog cells were tested in dog models of peripheral and coronary artery bypass. After six months, 88 percent of the baboon grafts were still open and trouble free. After one month, about 83 percent of the dog grafts were still open.
Researchers say that it is likely that the first place where tissue engineering will be used for blood vessels; however, for now. this technology would only be used as a last resort. In many cases, due to peripheral artery disease, or other weakness in the veins, using a person's own veins to replace a blood vessel to the heart is not possible.
But Alan P. Kyson, MD, a heart surgeon at Brody School of Medicine at East Carolina University told WebMD, "What's so exciting about this technology to me is that maybe one day, even in people who have (good) veins, we won't have to use their veins."
"We can just pull this stuff off the shelf. I don't have to cut your legs open. You don't have to complain of swelling and pain in your legs, you might avoid getting an infection, potentially, it will make your operation go quicker.... It will change the way we might do this surgery in the future."