Tooth loss is a widespread problem in adults and results in poor quality of life.
Currently, solutions to this problem include artificial teeth and implants.
But these aren’t as good as “real teeth,” and they don’t markedly improve quality
of life.
Now, scientists from Japan have made a discovery that can make re-growing teeth possible.
They found, with animal studies, that suppressing the gene USAG-1 by using its antibody can
efficiently lead to tooth growth.
The tooth fairy is a welcome guest for any child who has lost a tooth.
Not only will the fairy leave a small gift under the pillow, but the child can be assured
of a new tooth in a few months.
The same cannot be said of adults who have lost their teeth.
A new study by scientists at Kyoto University and the University of Fukui, however, may
offer some hope.
The team reports that an antibody for the gene USAG-1 can stimulate tooth growth in
mice suffering from tooth agenesis, a congenital condition.
The research paper was published in the journal Science Advances.
Although the normal adult mouth has 32 teeth, about 1% of the population has more or fewer
due to congenital conditions.
Scientists have explored the genetic causes for cases having too many teeth as clues for
regenerating teeth in adults.
According to the researcher of this study, the fundamental molecules responsible for
tooth development have already been identified.
The morphogenesis of individual teeth depends on the interactions of several molecules including
BMP, or bone morphogenetic protein, and Wnt signaling.
BMP and Wnt are involved in much more than tooth development.
They modulate the growth of multiple organs and tissues well before the human body is
even the size of a raisin.
Consequently drugs that directly affect their activity are commonly avoided, since side
effects could affect the entire body.
Guessing that targeting the factors that antagonize BMP and Wnt specifically in tooth development
could be safer, the team considered the gene USAG-1.
The researcher says that they knew that suppressing USAG-1 benefits tooth growth.
What they did not know was whether it would be enough.
The scientists therefore investigated the effects of several monoclonal antibodies for
USAG-1.
Monoclonal antibodies are commonly used to treat cancers, arthritis, and vaccine development.
USAG-1 interacts with both BMP and Wnt.
As a result, several of the antibodies led to poor birth and survival rates of the mice,
affirming the importance of both BMP and Wnt on whole body growth.
One promising antibody, however, disrupted the interaction of USAG-1 with BMP only.
Experiments with this antibody revealed that BMP signaling is essential for determining
the number of teeth in mice.
Moreover, a single administration was enough to generate a whole tooth.
Subsequent experiments showed the same benefits in ferrets.
Ferrets are diphyodont animals with similar dental patterns to humans.
The reseachers' next plan is to test the antibodies on other animals such as pigs and dogs.
The study is the first to show the benefits of monoclonal antibodies on tooth regeneration
and provides a new therapeutic framework for a clinical problem that can currently only
be resolved with implants and other artificial measures.
Conventional tissue engineering is not suitable for tooth regeneration.
This study shows that cell-free molecular therapy is effective for a wide range of congenital
tooth agenesis.