Cord blood
Cord blood yields ‘ethical’ embryonic stem cells
00:01 18 August 2005
NewScientist.com news service
Andy Coghlan
Hopes for treating disease with stem cells from umbilical cord blood
has received a major boost, following the discovery of primitive
cells with clinical potential matching that of the far more
controversial embryonic stem cells (ESCs). The latter are originally
derived from human fetuses, which are then destroyed, and have become
a major ethical issue, especially in the US.
Furthermore, the same team is applying new microgravity technology -
originally developed by NASA for the International Space Station – to
make large enough quantities of the stem cells to repair tissue
damage in patients.
The newly discovered human cells, named “cord-blood-derived
embryonic-like stem cells” or CBEs, are not quite as primitive as
embryonic stem cells, which can give rise to any tissue type of the
body. But they appear to be much more versatile than “adult stem
cells” such as those found in bone marrow which repair damaged tissue
during life.
“We have found a unique group of cells that bring together the
essential qualities of both types of stem cells for the first time,”
says Colin McGuckin of Kingston University in Surrey, UK, who co-led
the team with colleague Nico Forraz.
In laboratory experiments, the team successfully coaxed CBEs into
becoming liver cells. They also showed that the cells have most of
the surface “markers” considered as identifiers of embryonic stem
cells and form “embryoid bodies” – characteristic clumps of cells
formed by ESCs.
Ethically acceptable
But the factor that may make the discovery very significant is that
umbilical cord blood can be saved, stored and multiplied without any
of the ethical dilemmas facing embryonic stem cell use, which are
derived from human fetuses.
And with more and more “banks” around the world for saving cord
blood, the potential for finding tissue matches for every patient
becomes more and more realistic. “There are now eight banks in the UK
alone,” says McGuckin.
Stephen Minger, director of the Stem Cell Biology Laboratory at
King’s College London, UK, says he is “intrigued” by the claims but
would like to see more proof of the cells’ embryonic character. Can
they, for example, differentiate into the three fundamental cell
types that go on to form all adult tissues, he asks. McGuckin says
his team has already shown this, and that the work is awaiting
publication.
Free-floating production
The technology used by the team to start multiplying the CBEs was
originally developed for NASA by Synthecon Incorporated in Houston,
Texas, US, for isolating proteins with clinical potential from cells
grown aboard the International Space Station.
The spinning devices used essentially put “the cells in a constant
state of freefall in a liquid”, McGuckin explains. He says that in
these free-floating “three-dimensional” conditions, the cells grow
faster than if grown in “two dimensions” in a lab dish.
Nor do they need to be nourished from underneath by “feeder layers”
of animal cells which have been shown to contaminate human cells
grown, making them unsuitable for use in medical treatments.
“We’re now developing a new bioreactor to make considerably more,
which means we can make thousands and thousands more stem cells than
are available from embryonic sources,” says McGuckin.
Journal reference: Cell Proliferation (vol 38, p 245)
