In April of 2014, a major breakthrough was established in human
stem cell research. In that month two
laboratories independently reported the successful production of human
embryonic stem (ES) cells derived from skin cells cultured in the laboratory (
in-vitro). This a significant
achievement in that an application of this technique could be exceedingly
useful in the production of replacement tissues in-vitro for the treatment of
such diseases as juvenile (type 1)diabetes
and Parkinson’s disease – both of which arise from the precipitous loss of the
cells required to manufacture insulin and dopamine, respectively. The added benefit of such an approach is that
since the cells can be derived from the patient being treated, graft rejection
is no longer an issue.
The cloning technique that was employed is referred to as
somatic cell nuclear transfer (SCNT); an analogous method was used to clone the
now famous sheep, Dolly. It was
subsequently applied to cloning cattle, mice dogs and other animals. There is no desire among members of the
scientific community to apply this approach to cloning humans but rather to
produce early-stage human embryos from which ES cells could be derived. Heretofore, human cells have been
problematic in regards to cloning.
Dr. Dong Ryul Lee and his colleagues at CHA University in
Seoul, Korea successfully created human ES cells from the skin cells of two
individuals – men ranging in ages from 35 to 75 years old. Later in April of the same year, Dr. Dieter Egli
and his collaborators from the New York Stem Cell Foundation (NYSCF) Research
Institute used the skin cells of a young woman patient suffering from type 1
diabetes to also produce ES cells and then induced these cells to become
insulin-producing cells. Following this
momentous result, the investigative team then introduced these
insulin-producing cells into
experimental mice where it was shown that the hormone insulin was made in-vivo. This latter finding has yet to be published.
The overall technique that was employed in Egli’s laboratory
is briefly described below –
·
DNA is removed from an unfertilized human egg
cell (oocyte)
·
The DNA from skin cells grown in-vitro from a
patient with type 1 diabetes is transferred to the oocyte that had its own DNA
removed
·
If the transfer is successful, the oocyte begins
to divide
·
At a very early point in cell division – the
Blastocyst stage – ES cells are harvested
·
Finally, these cells are coaxed into
differentiating into insulin-producing pancreatic cells.
These results are very exciting; however, the possible application
to human disease faces considerable obstacles that need to be addressed. Nonetheless, it is a significant step in the
goal to successfully treat implacable diseases such as type 1 diabetes and
Parkinson’s through tissue –replacement therapies.
