Embryonic stem cell or ES cell(12-18)
Because of the limitations of adult stem cells,
embryonic stem cells are more promising as they
provide a more flexible differentiation potential. Based
on current evidence, scientists have proved that the
specialized cell developed from ES cell can grow into
diseased tissues and function properly in animal
models(19-20). These successful clinical applications in
animal models have been shown in severe combined
immune deficiency, diabetes mellitus type 1, Parkinson’s
disease, spinal cord injury and demyelinated diseases.
Nevertheless, there are still many limitations
to apply this knowledge and experience from animal
models into clinical practice.
1. A limitation of knowledge on an integration
of stem derived cells and tissues into recipient tissue
and long term regulation of transplantation.
2. A limitation on developing an adequate
amount of stem cells for therapeutic purposes in
humans since the amount of stem cells used in animal
models is small.
3. A contamination problem of mouse feeder
layer for human embryonic stem cells which can trigger
adverse immunological reaction and infection.
In conclusion, stem cell knowledge has been
rapidly developing during the past decade. In addition,
stem cells have been focused as a promising tool for
replacement therapy in the future. It is well established
theoretically that stem cells have numerous potentials
and unique useful clinical characteristics. However,
there are several technical limitations and ethical controversies
that require an appropriate solution before
further application