Cord blood yields 'ethical' embryonic stem cells
00:01 18 August 2005 by 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)
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