New York: Scientists at the University of Wisconsin-Madison (UW) have succeeded in growing functional vocal cord tissue in the laboratory, a major step toward restoring a voice to people who have lost their vocal cords to cancer surgery or other injuries.
The researchers from several disciplines were able to bio-engineer vocal cord tissue to transmit sound.
"Our vocal cords are made up of special tissue that has to be flexible enough to vibrate, yet strong enough to bang together hundreds of times per second. It's an exquisite system and a hard thing to replicate," said lead researcher Dr Nathan Welham, an associate professor of surgery in the UW School of Medicine.
Welham and colleagues began with vocal cord tissue from a cadaver and four patients who had their larynxes removed but did not have cancer.
Welham said the lab-grown tissue "felt like vocal cord tissue", and materials testing showed that it had qualities of viscosity and elasticity similar to normal tissue.
To see if it could transmit sound, the researchers transplanted the bio-engineered tissue onto one side of larynges that had been removed from cadaver dogs.
The larynges were attached to artificial windpipes and warm, humidified air was blown through them.
Not only did the tissue produce sound, but high-speed digital imaging showed the engineered mucosa vibrating like the native tissue on the opposing side.
"It seems like the engineered vocal cord tissue may be like cornea tissue in that it is immunoprivileged, meaning that it doesn't set off a host immune reaction," Welham said.
The findings were published in the journal Science Translational Medicine.