Lab-grown vocal cords bring hope of treating people with voice disorders

Lab-grown vocal cords

There is hope for people with voice disorders if the research conducted by UW-Madison scientists is successful. UW- Madison scientists have harvested human vocal cord tissue in a Petri dish, and it produced sound when transplanted into voice boxes from cadaver dogs.

Such implants may not be ready for human use as of now and would require testing that will take years. However the fact that recreating a tissue particularly the Vocal Fold and ensuring that it is functional is by itself a big deal. The vocal fold was functioning well in dog larynges and was also not rejected by the mouse model of the human immune system.

The research team was led by Nathan Welham, a UW-Madison speech-language pathologist who was excited about the latest discovery because it was created with actual human vocal fold cells and was functioning at an impressive level. The material will have a strong potential as a therapy.

The going has not been easy and the researchers were tasked with creating a replacement for the vocal cord that was soft and pliable to create waves of vibration but tough enough to weather rapid acceleration and stress.

Welham adds that there is no other tissue in the human body which endures so much stress and biomechanical demands. Welham along with Changying Ling, an associate scientist in Welham’s lab collected healthy vocal chords from a person who had just died and four other patients who had their larynx removed due to reasons other than cancer. The research team isolated and purified two types of cells –fibroblasts and epithelial cells and let it grow in a dish on a 3-D scaffold.

During two weeks, the cells started making tissues that produced the same proteins as normal vocal cord cells.

Brian Frey, another scientist, involved in the study said that they are effectively talking and interacting with one another, producing proteins that enable this special tissue capable of vibration. Frey added that using the correct cells and giving the right environment and let biology do the rest of the work.

Engineered Vocal Fold Tissue

The researchers then transplanted the artificial vocal chords onto larynges that were obtained from dead dogs and attached to artificial windpipes. When humidified air was blown through, the tissue produced a sound much akin to what human voice sounds before its modulation by throat, mouth and nose.