Implanted stem cells grow teeth in mice

Japanese scientists using stem cells have grown fully functional teeth in adult mice, which may hold promise for regrowing human organs, the scientists report.

The researchers developed a bioengineered tooth germ, or seed taken from a mouse embryo containing all the cells and instructions necessary to grow a tooth, they wrote in the journal Proceedings of the National Academy of Sciences.

Takashi Tsuji of the Tokyo University of Science and his colleagues then removed the upper first molars from 5-week-old mice, they said.

Three weeks later, after confirming no tooth remnants were still there, they transplanted the tooth germs into the mice jawbones.

Thirty-seven days later, the researchers noticed the bioengineered teeth broke through the gum and the rodents started nibbling with the new teeth, the article said.

The teeth, which had enamel and dentin just like natural teeth, also included nerve fibers, which responded to pain, The Times of London reported.

The technique could provide a prelude to the ability to grow new, fully functional bioengineered organs inside the body from stem cells or other germ cells, the researchers said in the study.

The ultimate goal of regenerative therapy is to develop fully functioning bioengineered organs which work in cooperation with surrounding tissues to replace organs that were lost or damaged as a result of disease, injury, or aging, the researchers said.

This study represents a substantial advance and emphasizes the potential for bioengineered organ replacement in future regenerative therapies, they said.