The
Science of Stem Cells
The
defining characteristics of stem cells are that they are capable
of self-renewal meaning they can divide numerous times and maintain
their undifferentiated state, and they are multipotent, meaning
they have the potential to change into or differentiate into several
different cell types. Scientists and doctors are optimistic about
the growing role of stem cells to treat serious diseases.
There are two broad types of stem cells: embryonic stem cells and adult stem cells. Embryonic stem cells have the ability to create all cell types in our bodies. They have tremendous potential, but have not yielded any proven treatments and have been found to form tumors when implanted in animals. Embryonic stem cells are usually created by collecting and culturing cells from an embryo, often resulting in the embryo's destruction. The ethical and technical issues surrounding embryonic stem cells present large hurdles for successful medical applications in the near future.
Adult
stem cells are multipotent, which can form more limited cell types
than embryonic stem cells. Although adult stem cells typically
can only create fewer tissue types, they are easier to control
in research and clinical applications. Additionally since adult
stem cells can be harvested from and used by the same patient,
both immunogenic rejection and ethical controversy can be averted.
As a result, adult stem cells are currently used to treat dozens
of diseases, and the number of applications for adult stem cells
being researched, or in clinical trials, or in clinical use continue
to grow.
There
are two basic subtypes of adult stem cells. Hematopoeitic stem
cells form blood cells and are typically found in bone marrow
or umbilical cord blood. Mesenchymal stem cells form connective
tissues such as bone, tendons, muscles, fat, and nerves as well
as liver and pancreatic cells. Mesenchymal stem cells are typically
found in bone marrow or the dental pulp in teeth.
Sources
of Stem cells
Current
stem cell therapies use cells obtained from bone marrow, umbilical
cord blood and peripheral blood which can be expensive, painful,
or complex to collect and use.
Recently,
scientists at the National Institutes of Health (NIH) discovered
that potent stem cells are found in both baby teeth and wisdom
teeth, providing a new, convenient source of stem cells.
Studies
show that Dental Stem Cells can develop into tissue types complementary
to those derived from umbilical cord blood, such as bone and other
connective tissues.
As
a result, researchers around the world are investigating the potential
of dental stem cells to become a routine source of stem cells
for regenerative medicine.
Current
and Emerging Applications
Adult
stem cells from bone marrow and umbilical cord blood have been
used for decades to treat patients for dozens of diseases. Many
more applications are being studied. With advances in the science
and medicine of stem cells, experts predict a coming future of
regenerative medicine enabled by stem cells, and in a broader
array of applications.
Dental
Stem Cells are a newly identified source of adult stem cells and
the earliest applications expected are the repair of damaged tooth
structures, bone regeneration, and possibly the treatment of neural
tissue injury or degenerative diseases (Proceedings of the National
Academy of Science, 2003).
Current
Stem Cells Applications
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