Here is news of a technology demonstration in which yet another part of the body has some of its component parts constructed in the laboratory and successfully tested for functionality:
Tissue engineers have for the first time made structures that not only resemble real vocal cords but also function like them. Impaired vocal cords make it hard or impossible for people to speak. There is currently no way to fix severe damage, which can result from surgery, traumatic injury, or diseases like cancer. The researchers implanted the engineered tissue into a larynx that had been taken from a dog and had one of its vocal cords removed. They demonstrated that the lab-made tissue vibrates and sounds like healthy tissue. Further tests in mice showed that the tissue elicited a minimal immune response, raising the researchers' hopes that such implants could eventually work in people.
Vocal cords are bands of tissue stretched horizontally on either side of the larynx, or voice box, just above the trachea, or windpipe. In recent years researchers have tried to re-create that structure in the lab, using polymer scaffolds to culture and grow stem cells in three dimensions - a well-established tissue engineering approach. But while they've made tissues that look the part, the engineered tissue has not vibrated effectively. Those previous attempts may have been limited because they didn't use cells from vocal cord tissue. This latest effort retrieved such cells from human cadavers and from donors who had healthy tissue removed during surgery. The researchers used a collagen scaffold to culture and grow the cells, and after a couple of weeks they had what resembled vocal cords. Subsequent protein analysis confirmed that it contained a large portion of the specific kinds of proteins found in the real tissue.
It will take at least several more years of development and testing before this process might be used in vocal cord transplants on people. But if further studies confirm the observation that tissue engineered from the cells of unrelated donors doesn't cause a harmful immune response, it should be possible to generate a large amount of vocal cord tissue from a small number of sources.