Tooth cells induce hair follicles to grow
Stem cell research has become a cutting edge phenomena in modern
science. Stem cells have been found to produce miraculous effects
toward the regeneration of certain biological parts of the body.
This promises many great things for the future.
One such area of the body that has been extensively researched
are the teeth and hair in both animals and humans. Scientists
have recently discovered that Mesenchymal stem cells in both tooth
and hair follicles can be interchanged between humans and animals
to produce positive effects in either of the transplanted areas.
An example of this was recently shown to be the case when both
animal and human tooth cells were first transferred into hair
follicles. This was done to see if they could help the growth
of human hair. The results were extremely interesting. It was
discovered that the transplantation of stem cells from both human
and animal teeth helped to stimulate healthier hair growth in
humans. Some of the tests were not as successful as others. The
results depended a lot upon the age of the donor and upon other
environmental factors. However, the overall results proved that
there is great hope for this type of treatment in hair growth
somewhere down the road.
Although teeth and hair follicles are extremely different items
on both the animal and human body, they actually have a lot of
similarities on the cellular level. Both teeth and hair are built
from very similar stem cells that merely group together in different
ways to eventually create the larger tooth or hair follicle formations.
The early stages of growth of these larger formations, which depends
upon the activity of stem cells, tends to be very similar.
Specifically, what happens when teeth and hair begin to form
is that the stem cells group together underneath the surface of
other, larger concentrations of cell growth. The process of this
gathering of cells is guided by certain governing cells called " papilla
cells" in hair follicle formation the cells are called “dermal
papilla” cells and in teeth they are called “dental
papilla” (or pulp) cells. These papilla cells are very versatile
governors because they can travel to entirely different "regions" of
tissue and govern the growth of cells in the foreign area just
as they do in their own region. Of course, there are some exceptions
to the rule and certain environmental characteristics often come
into play. Nevertheless, there is great promise for these dermal
papilla cells as scientists are just beginning to discover.
One particular procedure that scientists investigated took place
in an experiment involving whisker follicles. Scientists found
that, when a section just larger than one third the length of
any whisker follicle was removed, the remaining upper section
of the whisker follicle would become completely inactive and no
more hair growth would take place. The whisker that was cut off
from the bottom became essentially dead. Scientists took these
dead whiskers and were able to re-activate them by simply adding
dermal papilla cells to the upper "dead" follicle. The
amazing thing was that this didn't just work when transplanting
hair cells into whiskers, this proved to be true when scientists
transplanted tooth papilla cells as well! Furthermore, this result
was duplicated in both animal and human whiskers that received
the transplants and was also duplicated when both animals and
humans acted as the donors! The results, all around, had at least
some sort of positive effect.
The method by which these papilla cells were transferred into
the hair follicles was very interesting. It involved widening
the central canal of the hair follicle in order to allow for a
deposit of cells to be placed into the hair follicle itself. To
do this, scientists used fine tipped watchmaker forceps with papilla
cells packed inside! These scientists are very resourceful when
they want to be!
The scientists tried several different types of cells from different
rats as donors for their experiments. When they transplanted these
rat cells into the hair follicles, they found that the specific
papilla cells from the incisor teeth seemed to produce the best
results. They also found that 3 week old rats did the best as
cell donors rather than older rats. Newborn rats also did well,
but were not as successful as, specifically, the three week old
rat donors.
In all the cases of transplantation from rat donors, scientists
found one problem with the hair formation that resulted. The papilla
cells from animal teeth gave the unfortunate result of producing
small bone formations or tooth fragments in the hair follicles
where they were transplanted to. There had indeed been hair formation
due to the transplants of cells but the bone formations also grew
inside the hair follicles and that was obviously less than ideal.
When transplanting dental papilla cells from adult human teeth,
scientists had somewhat better results. For this experiment, they
chose two adult human donors. The first donor was a 22 year old
female and the second donor was a 34 year old female. After the
tooth cells were transplanted from the 22 year old donor into
the whisker follicles, scientists found that 3 out of 4 of the
follicle portions that had undergone transplants showed strong
hair production. The results were even better with the transplants
from the 34 year old donor. When those stem cells were transplanted
into the hair follicles, all of the follicle portions from that
donor showed strong hair production.
In terms of the age of the human tooth cell donors, it was found
that younger adult donors were not always the best choice for
transplantation methods. Although the younger human donor did
not produce the unfortunate result of bone formations in the transplanted
hair follicles that rat donors produced, the hair formations were
still not as good as they were from the 34 year old adult human.
Scientists found that it was best to stick with older adult human
donors when transplanting tooth cells into hair follicles.
In addition to the problems derived from transplanting animal
stem cells into human hair, dermal papilla cells also didn't do
as well going in the opposite direction from hair into teeth.
This seems self-evident, that you can't make teeth out of hair,
and yet scientists were sure to confirm what, to the rest of the
world may have already seemed like common sense! Scientists found
that when the papilla cells were transplanted from hair into teeth
there were obvious problems. The hair cells did not help to produce
the necessary dentine or the enamel that normal tooth cells usually
govern. For scientists, it was "back to the drawing board"!
The production of bone formations in hair follicles had seemed
an unfortunate blow to the growth of healthy human hair. The lack
of dentine and enamel similarly did not fair well for the growth
potential of teeth. Still, The success of transplanting human
stem cells from teeth to hair had been more successful.
Even with the success of transplanting human stem cells from
teeth into hair, there were still some problems in terms of the
applicability of the experiments to male pattern baldness in the
mainstream market. The experiments involved alot of extenuating
environmental conditions that simply were not practical for male
pattern baldness patients. Still, scientists have not been discouraged.
Scientists have gone on to suppose that the discovery of bone
formations in hair follicles could still be seen in a positive
light as it may be applied to future dental research. Although
the hair specialists may not appreciate it, the tooth specialists
just might! Scientists are now looking in new directions toward
the prospect that stem cells may still provide certain prospects
for the growth of both healthy hair and healthy teeth. The search
goes on.
Regardless of the mild success that they have had with human
hair growth, scientists still do not envisage a solution to male
pattern baldness just yet. They will continue to research stem
cells in the future and hopefully find new avenues in which their
discoveries can be applied. Stem cell research is truly making
headway as the cutting edge of scientific discovery. Hopefully,
the future will hopefully bring even better news.
Tooth cells induce hair follicles to grow references
- Reynolds AJ, Jahoda CA. Cultured human and
rat tooth papilla cells induce hair follicle regeneration and
fiber growth. Differentiation. 2004 Dec;72(9-10):566-75.
PMID: 15617567
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