In an experimental first, scientists reported Wednesday that they have grown about 170 human vocal cords in a lab, starting from cells taken from four surgical patients and one cadaver.
About 20 million Americans have vocal cord injuries, and they’ve plagued some of the world’s most famous singers, including Julie Andrews, Adele, and John Mayer. The new medical engineering feat is a first step in developing better treatments for the worst of these cases.
Preliminary animal experiments suggest the lab-grown voice boxes will perform like real ones, unlike current repairs for damaged vocal cords, the scientists reported in the journal Science Translational Medicine. And the lab-grown vocal cords didn’t require immune system drugs, unlike most other transplant tissues.
“We never imagined that we would see the impressive level of function that we did,” said study senior author Nathan Welham of the University of Wisconsin Medical School at a briefing for reporters.
Although it’s still very early, Welham and his colleagues envision someday growing new voice boxes for people with the most severe scarring, and then implanting them surgically. Smaller vocal cord scars could be patched with the lab-grown tissues.
“What makes this tremendously exciting is that we just don’t have great treatments for these people,” Seth Cohen, a head and neck surgeon at Duke University who was not part of the study team, told BuzzFeed News. “You don’t miss your voice until it is gone, and then you really miss it. People cannot work and they suffer tremendous isolation.”
In the study, the team implanted their lab-grown vocal cords into the kidneys of mice genetically engineered to possess a human immune system. (Why kidneys? “We had to,” Welham said. “Their larynx is way too small.”) The tissues grafted without need of transplant drugs.
“This is not too surprising. The larynx has to be tolerant of everything we eat and breathe,” Jennifer Long, a otolaryngologist at UCLA who was not part of the study, told BuzzFeed News. But the immune system tolerance makes the prospect of transplants of lab-grown vocal cords much more appealing, she added. “You don’t want swelling from an immune reaction in your windpipe.”
The study team also attached the voice tissues to the removed larynxes of two laboratory dogs (ones donated from other research, not killed for the experiments), placed them in a plastic tube designed to mimic the human windpipe, and blew wind through them, mimicking exhalations to produce tones very close to natural voice boxes.
“It sounded like a kazoo,” Welham said. “An ‘eeeee’ noise.”
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SOURCE: Buzzfeed News, Dan Vergano