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[IP] Stem cell research doubts


Wednesday, 13 March, 2002, 22:06 GMT
Stem cell research doubts

The potential of stem cell therapy is hotly debated The use of adult stem
cells to develop new transplant therapies might be seriously flawed, a group
of scientists said on Wednesday.

The UK and US researchers claimed to have
found abnormalities in the way the cells
behaved when studied closely in the lab.

The scientists from Edinburgh and Gainesville said it was essential that
work continued on embryonic sources of the special cells to see if they had
better potential.

The medical world is hopeful that stem cells,
the master cells in the body that can develop
into other cell types, could form the basis of
novel treatments for degenerative conditions
such as Parkinson's and heart disease.

But the field is a controversial one because
some scientists believe the best source of the
cells will come from embryos that have been
cloned from patients' own tissues.

Fluorescent markers

Recent studies have shown that adult stem
cells from one tissue such as blood, can give
rise to other cell types, such as nerve and

The adult cells are thought to revert to a state similar to that of
embryonic stem cells, which are even less specialised, before becoming the
new cell types.

Scientists at Edinburgh University took adult
stem cells from mouse brains and marked them with a fluorescent tag. The
researchers then mixed them with embryonic stem cells in a petri dish.

And on first examination, it appeared that the
adult brain cells had indeed reverted to the
less specialized state of the cells placed
alongside them. However, on closer examination, the new cells proliferating
in the
petri dish contained the florescent marker from
the brain cells and the DNA from the embryonic stem cells.

In other words, the adult cells had simply fused with the embryonic ones -
the new cells
had twice the number of chromosomes
("packets" of genetic material).

If used in humans, these hybrid cells could
have unknown effects on the body.

Similar results were seen by scientists at the
University of Florida in Gainesville.

No restrictions on stem cell work

Professor Austin Smith, who was behind the
British work, said if the study results were
confirmed then it would put a big question
mark against the use of adult stem cells.

"If nothing else, our study indicates that calls
for a halt to embryonic stem cell research are
not scientifically justified and confirms the
far-sightedness of the UK legislature in
approving embryonic stem cell derivation and

Stem cells have the potential to grow into
nearly all the different kinds of tissue in the
body, including nerves, bone, skin, muscle and organs.

Allied with cloning technology, they could
prove revolutionary in organ regeneration -
organ transplants can fail because the body's
immune system rejects the new "foreign"

Using stem cells taken from a patient's embryo
clone to create replacement cells could
completely bypass the problem of tissue

Not applicable

But Professor Nick Wright, from Cancer
Research UK, said that nothing shown in this
research cast doubt in his mind on the results
of adult stem cell research in animals.

"These are extremely preliminary results and
are not applicable to adult stem cells," he told
BBC News Online.

Professor Wright himself published research
showing how damaged livers can be repaired
using adult stem cells taken from bone marrow.

He said this new research had only been
carried out in the test tube and not in living
animals and so could only be applied to this
one particular situation.

He added that polypliody - having more than
one set of chromosomes in a cell - occurred
naturally in the liver anyway.

The Edinburgh/Gainesville work is published in the journal Nature.
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