A new study shows that stem cells extracted from urine can be turned into rudimentary tooth-like structures. Oh, and the researchers did so by growing the teeth inside the kidneys of mice.


To make the teeth, Duanqing Pei, who works at the Chinese Academy of Sciences in Guangzhou, mixed the stem cells with the connective tissue cells of mice. This concoction was grown for two days prior to being implanted under the outer layer of a mouse's kidney. Once there, the cells were coaxed into becoming dental epithelial tissue, and eventually enamel.


It's worth noting that the teeth were softer than normal teeth (probably because they were not being used as they grew), and they were a bit misshapen. The researchers don't know how to grow them such that they have the exact shape and size of specific teeth (like molars or incisors).

But eventually, the researchers hope to overcome these problems and see their technique used in clinical settings.

"Teeth are vital not only for a good smile, but also good health," write the authors in the study. "Yet, we lose teeth regularly due to accidents or diseases. An ideal solution to this problem is to regenerate teeth with patients’ own cells."

As for using human urine as the source for the cells, Pei said it was because it's "the most convenient source."


But Chris Mason, a stem cell biologists at University College London, told the BBC that urine is a poor starting point:

"It is probably one of the worst sources, there are very few cells in the first place and the efficiency of turning them into stem cells is very low. "You just wouldn't do it in this way." He also warned that the risk of contamination, such as through bacteria, was much higher than with other sources of cells. Prof Mason added: "The big challenge here is the teeth have got a pulp with nerve and blood vessels which have to make sure they integrate to get permanent teeth."


Read the entire study at Cell Regeneration Journal.

Image: Chinese Academy of Sciences.