Biomedical Engineering Reference
In-Depth Information
currently very few technologies close to clinical success that have
been derived from human embryonic stem cells.
While for many people the isolation of human embryonic stem
cells heralded the start of a new kind of medicine, the reality is that
this was an incremental development with a long history. Not as
radically new as it often appears, the existence of human embryonic
stem cells had been known for some time, but no one had been able
to isolate them prior to 1998. The burgeoning global interest in
human embryonic stem cells owes its success to decades of
incremental research that began with teratocarcinomas and
embryonal carcinoma cells, decades before finally developing into
research on embryonic stem cells (Solter, 2006).
Teratocarcinoma research in the early 1950s explored how
traditional teratomas could continue to grow when transplanted
(Solter, 2006). Teratomas are rare, benign spontaneous growths
emerging from the sex organs, often appearing with teeth, hair and
other human-like characteristics. Teratocarcinomas occur when
these growths continue developing, threatening the life of the
organism in which they are found. Experimental work in the 1950s
on the origins and growth mechanisms of teratocarcinomas in mice
showed that a small collection of cells found in the gonads were
responsible for their development (Solter, 2006). Another experiment
highlighted how just a single cell from this group could produce all
the cell tissues of the teratocarcinoma when implanted into the
abdomen of a mouse, resulting in the hypothesis that teratocarcinoma
cells were highly similar to embryonic cells, if not the same (Solter,
2006). Further experimental work in the 1960s on mice showed that
when grown
in vitro
, the teratocarcinoma cells started to exhibit
features similar to early embryos, resulting in them being called
embryonal carcinoma cells (Solter, 2006). Further experimentation
throughout the 1960s and 1970s with mouse and human embryonal
carcinoma cells led to the eventual attempts to derive embryonal
cells directly, with mouse embryonal cells being isolated and grown
in vitro
in 1981 (Solter, 2006). Since then, whole mice have been
grown from one embryonal cell (Solter, 2006).
The isolation and
in vitro
growth of human embryonic stem cells
indicated that the same principle might be applied to human tissues.
