Blood Vessels Grown From Muscle Cells
Engineered Blood Vessel Grafts Could Be Used for Heart Bypass, Kidney Dialysis
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Bioengineering Blood Vessels continued...
The researchers have not yet tested the bioengineered vessels in humans, but Dahl says this study lays the foundation to do that.
“We estimate that 500,000 patients a year could potentially benefit,” says Dahl.
At least initially, Dahl thinks those will be patients who might need vessels to help reroute blood around blockages in the heart, or for whom doctors need to build an access point so that their blood can be cleaned for kidney dialysis.
“Tissue engineering is a very important frontier in medicine,” says study researcher Jeffrey H. Lawson, MD, a vascular surgeon at Duke University Medical Center.
“Replacing and understanding the complexity of the human body and its specific parts is really quite a challenge. Probably the first places where tissue engineering will become a reality will be in things like blood vessels, because they’re relatively straightforward structurally to construct, even though they’re still amazingly complex,” he says.
A New Way to Replace Blood Vessels
When blood vessels around the heart become dangerously congested with plaques, surgeons will reroute blood flow and bypass the blockages.
To do that, they may take blood vessels from other parts of the body, usually the leg or chest wall.
But there are cases when a person’s own blood vessels can’t be harvested. In those cases, a surgeon may reach for vessels made from synthetic polymers, like Teflon or Dacron, or for vessels donated from cadavers.
“It works OK, but it gets infected more than your natural tissue, and it tends to clot off,” Lawson says.
That’s where off-the-shelf bioengineered grafts may play a role.
In the 15 years that Humacyte’s grafts have been in development, Lawson says they have made enormous progress.
“Initially, the earliest prototypes were like sewing on wet toilet paper, which wasn’t very much fun as a surgeon. They would rip. So they’ve made remarkable progress and now it’s something that sews like a vein,” Lawson says.
Indeed, researchers made sure the tissue was strong enough to hold sutures by hanging weights from the tissues with surgical thread. They also inflated them with saline solution periodically to see how much pressure it would take to make them burst.
Until they can be proven to be reliably safe and effective, bioengineered blood vessels are most likely to be used as a last resort, but some doctors envision a day when they may become the norm.
“What’s so exciting about this technology to me is that maybe one day, even in people who have veins, we won’t have to use their veins,” says study researcher Alan P. Kypson, MD, a heart surgeon at the Brody School of Medicine at East Carolina University.
“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,” Kypson says. “It will change the way we might do this surgery in the future.”