Scientists Grow Mouse Teeth From Single Cells/OT

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Scientists Grow Mouse Teeth From Single Cells

02.19.07, 12:00 AM ET

MONDAY, Feb. 19 (HealthDay News) -- Using tissue regeneration

technology, Japanese researchers have been able to grow a new tooth

from single mouse tooth cells and use it to replace natural teeth in

a mouse.

The achievement is " a breakthrough in the development of

bioengineered organs and proposes a novel concept for the organ

replacement in future regenerative therapies, " lead researcher

Takashi Tsuji, associate professor, Department of Biological

Technology, Tokyo University of Science, said in a prepared statement.

Reporting in the Feb. 19 online issue of the journal Nature Methods,

Tsuji's team started by using the two cell types that form teeth --

mesenchymal and epithelial cells. They grew sufficient quantities of

each of these cells and then injected them into a drop of collagen.

This eventually developed into a budding tooth, which they

transplanted into the cavity left by an extracted tooth in a mouse.

The new tooth developed normally and had the same composition and

structure as natural teeth, the researchers reported. Ultimately,

such bioengineered teeth could be used instead of inlays or synthetic

implants, they said.

In addition, the new method might be applied to re-growing other

organs. In fact, the researchers used similar methods to re-grow a

mouse hair follicle that would eventually form a whisker.

" This method would be able to adopt the reconstitution of a wide

variety of organs such as whisker, hair follicle, kidney and liver, "

Tsuji said.

He said the study increases the understanding of principles by which

organ reconstitution can be achieved using bioengineered tissues.

" Our results therefore make a substantial contribution to the

development of bioengineering technologies and the future

reconstitution of primordial organs, " the Japanese researcher

said. " Our present findings should also encourage the future

development of organ replacement by regenerative therapy. "

But one expert believes this approach is still in its infancy.

" The developed tooth doesn't develop very far. As far as generating a

functional, full size tooth in humans, we still have the same

limitations of getting there, " said Pamela C. Yelick, the director of

the Division of Craniofacial and Molecular Genetics and an associate

professor in the Department of Oral and Maxillofacial Pathology at

Tufts University in Boston.

Her team has attempted similar work, she said, but the Japanese

tooth " doesn't develop any farther than our bioengineered teeth did. "

According to Yelick, the problem with all bioengineered teeth is

that, so far, they can't be made to form specific teeth. " The

limitations are generating teeth of predetermined size and shape,

which really is the big stumbling block, " she said.

" Tooth root formation is a big problem, " too, she said. Tsuji's group

was able to develop preliminary root structures, she said, " but they

are not the functional roots that are really required for a

functional tooth to stay in place. "

However, Yelick remains optimistic. She predicts that, one day, there

will be tissues engineered to replace damaged parts of organs, and

even whole organs will be grown outside the body for

transplant. " Every day, progress is being made, " she said

forbes.com