Hurdles remain, but technology
might someday regenerate other structures, organs
By Steven Reinberg,
HealthDay Reporter
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 aand 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
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
More
information
For
more on tissue regeneration, visit the Pittsburgh
Tissue Engineering Initiative.