Scientists grow human teeth from stem cells in urine
Teeth are important for a good smile, as well as good health. Yet, teeth are lost regularly due to accidents or diseases. An ideal solution to this problem would be the ability to regenerate teeth with a person’s own cells.
Indeed, stem cells derived from human urine could be used to generate solid organs and tissues, including teeth, according to Chinese researchers in a study published this week in the journal Cell Regeneration. The researchers are hopeful the technique will open the door to providing new, tailor-made teeth for dental patients.
Previous stem cell studies have demonstrated how cells can be generated from urine, which has led to the discovery that cells discarded with urea can become induced pluripotent stem cells (iPSCs), which can then generate many different cell types, including neurons and heart muscle cells.
In groundbreaking tissue research, Duanqing Pei and his colleagues from Guangzhou Institutes of Biomedicine and Health, along with other Chinese universities, have developed a unique chimeric tissue culture technique that can lure these iPSCs into tiny structures that resemble teeth.
Their technique mimics normal tooth development that results from an interaction between two different cell types: 1) epithelial cells, which produce enamel; and 2) mesenchymal cells, which produce the primary three tooth components consisting of dentin, cementum and pulp.
For the study, the researchers first used chemicals to entice the cultured iPSCs into flat sheets of epithelial cells. Next, they combined these cells with mouse embryonic mesenchymal cells, and then transplanted them into mice.
After three weeks, structures had grown that physically resembled human teeth. They also had the same elasticity as human teeth and contained pulp, dentin and enamel-forming cells.
This breakthrough offers new hope for the future of regenerative medicine. By the same token, the technique used to generate human teeth-like structures involves mouse cells, and has a success rate of only 30 percent. Moreover, the structures are approximately only one-third as hard as human teeth.
Accordingly, the researchers says human mesenchymal stem cells could be substituted for mouse cells, and the tissue culture conditions tweaked in order to resolve the problem. By doing this, it could theoretically result in the creation of a bioengineered tooth bud that has been cultured in a jar and then transplanted into the jawbone of a human patient to form a fully functional tooth.
When it comes to the field of regenerative medicine, iPSCs continue to be a tremendous source of optimism for two main reasons: 1) they avoid the controversial use of embryos; and 2) they come from a more readily available source than even cultured skin and blood.
SOURCE: Journal, Cell Regeneration, "Generation of tooth-like structures from integration-free human urine-induced pluripotent stem cells", published online July 30, 2013 (doi:10.1186/2045-9769-2-6)