"Long before it's in the papers"
June 04, 2013


Scientists report growing new teeth for mice, in place

Aug. 3, 2009
Courtesy PNAS
and World Science staff

Re­search­ers say they have en­gi­neered the growth of fully func­tion­al re­place­ment teeth in mice, with the growth oc­cur­ring in the tooth’s prop­er place.

Tech­nol­o­gy ex­ists to de­vel­op some tis­sues in the lab that can be trans­planted in­to an­i­mals. But Et­suko Ike­da of To­kyo-based Or­gan Tech­no­log­ies Inc. and To­kyo Un­ivers­ity of Sci­ence in Chi­ba, Ja­pan, and col­leagues ex­plored ways to grow an or­gan in place.

A glow­ing tooth re­gen­er­at­ed in an adult mouse mouth. (Im­age cour­te­sy  Ta­ka­shi Tsuji, PhD., To­kyo Uni­ver­si­ty of Sci­ence, Or­gan Tech­nolo­gies Inc.)

The work could serve as a prel­ude to oth­er or­gan re­place­ments us­ing a si­m­i­lar tech­nique, they pro­posed.

The re­search­ers de­vel­oped a bioen­gi­neered tooth germ, a seed-like tis­sue con­tain­ing the cells and ge­net­ic in­struc­tions nec­es­sary to form a tooth. They then trans­planted the germ in­to the jaw­bones of mice.

The germs reg­u­larly grew in­to re­place­ment teeth, the in­ves­ti­ga­tors said. Track­ing gene ac­ti­vity in the trans­planted germ with a flu­o­res­cent glow­ing pro­tein, the re­search­ers found that genes nor­mally ac­tivated in tooth de­vel­opment were al­so ac­tive dur­ing the en­gi­neered re­place­ment’s growth. 

The en­gi­neered tooth’s hard­ness was com­pa­ra­ble to that of nat­u­ral teeth, and nerve fibers could grow through­out and re­spond to pain stimula­t­ion, they al­so found. The re­sults are re­ported in this week’s early on­line edi­tion of the re­search jour­nal Pro­ceed­ings of the Na­tio­n­al Aca­de­my of Sci­en­ces.

“We pro­pose this tech­nol­o­gy as a mod­el for fu­ture or­gan re­place­ment ther­a­pies,” the re­search­ers wrote.

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Researchers say they have engineered the growth of fully functional replacement teeth in mice, with the growth occurring in the tooth’s proper place. Technology exists to develop limited tissues in the lab that can be transplanted into animals, but Etsuko Ikeda of Tokyo University of Science in Chiba, Japan and colleagues explored ways to grow a three-dimensional organ in place. The work could serve as a prelude to other organ replacements using a similar technique, they proposed. The researchers developed a bioengineered tooth germ, a seed-like tissue containing the cells and genetic instructions necessary to form a tooth. They then transplanted the germ into the jawbones of mice. The germs regularly grew into replacement teeth, the investigators said. Tracking gene activity in the transplanted germ with a fluorescent glowing protein, the researchers found that genes normally activated in tooth development were also active during the engineered replacement’s growth. The engineered tooth’s hardness was comparable to that of natural teeth, and nerve fibers could grow throughout and respond to pain stimulation, they also found. The results are reported in this week’s early online edition of the research journal pnas. “We propose this technology as a model for future organ replacement therapies,” the researchers wrote.