GENET archive


8-Humans: Scientists raise hope for sickle cell patients

                                 PART I
------------------------------- GENET-news -------------------------------

TITLE:  Scientists raise hope for sickle cell patients
SOURCE: The Guardian, UK, by Alok Jha,11381,1683060,00.html?
DATE:   10 Jan 2006

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Scientists raise hope for sickle cell patients

- Cloned cultures could replace marrow donors
- Embryonic stem cells may offer breakthrough

Scientists have developed a technique using embryonic stem cells to
treat the genetic abnormality that causes sickle cell anaemia.

Sickle cell anaemia is one of the most common genetic disorders
worldwide and primarily affects people of African, Mediterranean, Middle
Eastern and Indian descent. More than 6,000 people in the UK are thought
to have the disease.

It is caused by a genetic mutation producing abnormal haemoglobin, the
molecule inside red blood cells which carries oxygen. While healthy red
blood cells can bend and flex easily, the abnormal haemoglobin makes
cells rigid and sickle-shaped and as a result they cannot squeeze
through small blood vessels. This prevents oxygen from getting to where
it is needed, causing severe pain and damage to organs such as the
liver, kidney, lungs, heart and spleen. In extreme cases, sickle cell
anaemia can lead to death.

Although symptoms can be treated, a cure is only possible with a bone
marrow transplant from a donor. Scientists searching for drugs to
prevent the sickle cells sticking together have so far had no success.
Stem cells - the body's master cells which can be turned into tissue of
different kinds - from the umbilical cord have been used in the past to
treat the disease, but did not greatly increase the pool of available
donor tissue. However, embryonic stem cells, which have the greatest
potential to become any kind of tissue, could get around the current

Yuet Wai Kan, of the University of California at San Francisco, used
genetically-engineered mice carrying human genes with the sickle cell
mutation to produce embryos. He extracted stem cells from the embryos
when they were just a few days old, a stage called a blastocyst.

Dr Kan replaced the defective haemoglobin genes in these stem cells with
healthy versions and grew blood cells from them. All the cells which
grew from these stem cells turned out healthy.

The results appear today in the journal Proceedings of the National
Academy of Sciences. "This approach can be applied to human [embryonic
stem] cells to correct the sickle mutation," said the researchers.
"Theoretically, such an approach could be used to treat sickle cell
anaemia for those clinically severe patients who do not have
[compatible] donors for transplantation."

In theory, this type of corrected stem cell could be produced from a
cloned embryo produced from a person suffering from sickle cell anaemia,
and then injected back into their body to produce a supply of healthy
and normal blood cells. Because stem cells can be cultured and grown
indefinitely in the laboratory, doctors using this technique in future
would have a much larger choice of tissue to match their patients'
requirements, removing the need for bone marrow donors.

The technique is in its earliest stages with the production of embryonic
stem cells a costly business. Dr Kan's team successfully produced only
12 embryonic stem cell lines from 129 fertilised eggs.

But he and his colleagues are optimistic about the applications of their
work, adding that it could also be used to cure beta-thalassaemia,
another inherited blood disorder where abnormal haemoglobin leaves blood
cells prone to mechanical injury and early death.

                                 PART II
------------------------------- GENET-news -------------------------------

TITLE:  Royal Society urges caution on cloning claims
SOURCE: The Guardian, UK, by Liz Ford and agencies
DATE:   10 Jan 2006

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Royal Society urges caution on cloning claims

Scientists must guard against becoming "blinded by the prospect of
public acclaim" when conducting cloning and stem cell research, the
Royal Society warned today.

Following the revelations that the claims by the South Korean scientist
Hwang Woo-suk to have cloned human embryonic stem cells were fake, the
society said researchers assessing new results should remain sceptical
until they were confirmed by another laboratory.

The chairman of the society, Sir Richard Gardner, said: "The latest
revelations from South Korea emphasise the need for independent
confirmation of the results of research in this high profile field."

Opponents of stem cell research might try to use this "example of
wrongdoing" to further their campaigns, he added, warning that peer
review was not a foolproof method of detecting erroneous or fabricated

Sir Richard did, however, go on to say that it was vital high quality
research continued in this "exciting field".

The Institute for Stem Cell Research, at Edinburgh University, said Dr
Hwang's fraud did not alter the opinion of most scientists that patient-
specific stem cell lines could be cloned.

"Most importantly, therefore, these revelations about Dr Hwang do not
invalidate the body of rigorous scientific evidence supporting the
potential of a range of human stem cells, including embryonic stem
cells, to provide medical benefit," the institute said in a statement.

Today's announcement by Seoul National University followed months of
speculation about the validity of Dr Hwang's work.

The panel ruled that the scientist - hailed as a pioneer of stem cell
research and tipped for a future Nobel prize - "did not have any proof
to show that cloned embryonic stem cells were ever created" and disputed
claims in his 2004 paper published in the journal Science that he cloned
a human embryo and extracted stem cells from it.

It did, however, uphold Dr Hwang's claims last year to have created the
world's first cloned dog, an Afghan hound named Snuppy.

Last month, the university concluded that Dr Hwang had fabricated
results published last year in another article in Science. The panel
said it could not find any of the 11 stem cell lines matched to
patients, as Dr Hwang had reported to have done in that research.

Dr Hwang had also come under fire for using human eggs in his studies
donated by junior researchers on his team.

He conceded in November that two scientists had donated eggs without his
knowledge and that other women were paid to take fertility drugs to
produce eggs for research. Both practices are viewed as coercive and

Dr Hwang resigned from the university last month. He maintains that he
has the technology to clone stem cells.

Scientists hope one day to use human stem cells - master cells that can
grow into any body tissue - to cure diseases such as Alzheimer's and diabetes.

Creating stem cells genetically matched to a specific patient would be a
breakthrough because they would not be rejected by the patient's immune
systems. But despite years of research, Dr Hwang was the only person to
claim success in extracting the cells from an embryo.


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