(Credit: Duke Medicine)
In an operation that's the first of its kind for the US, surgeons have implanted a bioengineered blood vessel into a human patient.
We hear a bit about exciting technologies that are creating lab-grown body parts — but, while humans have been experimenting with bioengineering for quite some time, the trials have been pretty strictly off-limits to humans (although mice are OK).
That quietly ended in December last year, when Poland started a human clinical trial on lab-grown blood vessels. Now, the trial has moved over to the US, with the very first patient, a 62-year-old man suffering renal failure, receiving a vein grown entirely in a laboratory from surgeons at the Duke University Hospital in Durham, North Carolina, on 5 June.
The process of building the vein is the result of a 15-year research collaboration between Jeffrey H Lawson, MD, PhD, a vascular surgeon and vascular biologist at Duke Medicine, and Laura Niklason, MD, PhD, co-founder of Duke spin-off company Humacyte and a former faculty member at Duke, who is now at Yale.
The vein is constructed using a biodegradable tubular mesh scaffolding. This is seeded with donated human tissue, and placed in a culture bath of amino acids, vitamins and nutrients. Starting in the early stages, nutrients are pumped through the vein in a heartbeat rhythm to prepare the tissue for application. As the cells grow, the scaffolding dissolves, leaving behind a tubular blood vessel.
This is then treated to remove the chance of implant rejection. The vein is washed using a solution that rinses out the cellular properties. The resulting collagen structure does not trigger an immune response. Of course, the researchers could have created the veins using the patient's own tissue — but this process is too time consuming, and rules out mass production.
Another benefit of using this type of vein, Nklason and Lawson explained, is that unlike other available vein replacements made of Teflon or Dacron, the vein is flexible and adopts the cellular properties of the vein to which it is grafted. "They are functionally alive," Lawson said. "We won't know until we test it if it works this way in humans, but we know from the animal models that the blood travels through the blood vessels, and they have the natural properties that keep the blood cells healthy."
The first operation saw the vein implanted in an easily accessible site in the patient's arm.
"This is a pioneering event in medicine," said Lawson. "It's exciting to see something you've worked on for so long become a reality. We talk about translational technology — developing ideas from the laboratory to clinical practice — and this only happens where there is the multi-disciplinary support and collaboration to cultivate it."
The US Food and Drug Administration has approved 20 such implantations, after which the research team will undertake a safety review.