Researchers use urine to make new teeth
Toothless smiles may soon be saved by a very unlikely source: human urine.
Chinese researchers have found a way to generate solid organs and tissues—including teeth—out of stem cells derived from urine, Medical News Today reported.
"Previous stem cell research has shown how cells can be generated from urine. It is also known that cells discarded with urea can become induced pluripotent stem cells (iPSCs) that can then generate many different cell types, including neurons and heart muscle cells," it said.
It said a team from Guangzhou Institutes of Biomedicine and Health and other Chinese universities, led by Duanqing Pei, developed a chimeric tissue culture system that can induce these iPSCs into tiny structures that resemble teeth.
Such cells have the advantage of coming from a more readily accessible source than even cultured skin and blood.
"Furthermore, cells generated by this method cannot be rejected by the human immune system, being derived from the host's own cellular material," the report said.
The study is published this week in the open-access journal Cell Regeneration.
With the study, the researchers hope the technique may help provide "new, tailor-made teeth for dental patients."
Mimicking normal tooth development
The system by the researchers involves epithelial cells producing enamel, and mesenchymal cells that generate the other three main tooth components of dentin, cementum and pulp, thus mimicking normal tooth development.
In growing the new teeth, the team used chemicals to make flat sheets of epithelial cells out of the cultured iPSCs, then mixed these with mouse embryonic mesenchymal cells.
Once transplanted them into mice, the mix developed to "physically and structurally" resemble human teeth.
"They are of roughly the same elasticity, and contain pulp, dentin and enamel-forming cells," Medical News Today said.
Still too early
However, the report said it may still be too early to grow actual human teeth: the method involves mouse cells, and has a success rate of only 30 percent.
Also, the structures are only about one-third as hard as human teeth.
For now, the team said human mesenchymal stem cells could be substituted for those of mice, and the tissue culture conditions could be tweaked.
"In theory, this revised method could create a bioengineered tooth bud, cultured in a jar and then transplanted into the jawbone of a human patient to form a fully functional tooth," the report said.
A separate report on Mashable quoted University College London researcher Chris Mason as saying urine could be one of the "worst" sources of stem cells.
"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," it quoted him as telling the BBC.
He added bacteria in urine may present a risk of contamination higher than other sources.
"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," he added. — TJD, GMA News