Vocal cord tissue in a dish could treat voice disorders
Cancer can damage the larynx (voice box). Photo: Getty
US researchers have grown vocal cord tissue in a lab, an advance that could one day help restore the voices of millions who suffer from cancer or other diseases.
For now, the research is in the early stages, according to the study in Science Translational Medicine.
The tissue has been shown to last for three months in mice that were engineered to have a human-like immune system, and produced sound vibrations when transplanted into intact voice boxes from dog cadavers.
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Lead researcher Dr Nathan Welham, a speech-language pathologist from the University of Wisconsin at Madison, said the advance was important because vocal cords are “an exquisite system and a hard thing to replicate”.
“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,” Dr Welham said.
Cancer can damage the larynx (voice box). Photo: Getty
The bio-engineered tissue was grown over the course of two weeks, using healthy vocal fold cells – known as fibroblasts and epithelial cells – from surgical patients who had these cells removed for unrelated reasons.
The cells were isolated, purified and applied to a three-dimensional collagen scaffold, much like the kind scientists use to grow artificial skin in the lab.
When grown, the “cells assembled into layers that closely resembled the structure and protein makeup of natural vocal cord mucosa”, the researchers reported.
To see if the engineered tissue would work, it was transplanted into voice boxes that had been excised from deceased dogs. When humid air was blown through, the tissue vibrated and produced sound the way scientists expected it would.
The tissue also feels like natural vocal cords, and is moist and elastic like the real thing, Dr Welham said.
Finally, the tissue was then inserted into mice that had been engineered to have human immune systems to see if it would be accepted or rejected. The tissue grew and was not rejected, performing well regardless of whether the mice had the donor’s immune system or a different immune system.
“It seems like the engineered vocal cord tissue may be like cornea tissue … in that it doesn’t set off a host reaction,” Dr Welham said.
While it is likely to be years before such engineered tissue is widely available to those in need, researchers say their work is a promising step forward for those with vocal cord dysfunction.
“Voice is a pretty amazing thing, yet we don’t give it much thought until something goes wrong,” Dr Welham said.