The Strait Times, Singapore
April 25, 2003

Leap in stem cell research fuels call to ease US restrictions

American scientists worry that Bush policy on embryos may force them
to lag behind as advances are made in S'pore and Johns Hopkins

WASHINGTON - A series of important advances - including one from
Singapore - has boosted the potential of human embryonic stem cells
to treat heart disease, spinal cord injuries and other ailments, but
researchers in the United States say they are unable to take
advantage of the new techniques under a government policy that
requires federally supported scientists to use older colonies of stem
cells.

Now pressure is building from scientists, patient advocates and
members of Congress to loosen the embryo-protecting restrictions
imposed by President George W. Bush, with some on Capitol Hill saying
they want to take up the issue next month.

Stem cells obtained from five-day-old human embryos can morph into
all kinds of human tissues and appear capable of regenerating ailing
organs.

But while newer and safer versions of the cells have been created
recently, the policy imposed by Mr Bush in 2001 puts those cells off-
limits to any scientist whose work is supported with federal money.

Supporters of embryo cell research have long grumbled about the
policy, but have acknowledged that their complaints were largely
theoretical because there was still plenty to learn from older cells.

The unexpectedly rapid advent of more medically promising cells and
the possibility of human studies within the next year or so have
changed that equation, they say, making the Bush policy a real
barrier to progress.

The older cells allowed under the Bush plan are problematic because
they have been grown in mixtures with mouse tumour cells. The tumour
cells, known as 'feeder' cells, secrete crucial, though as yet
unidentified, nutrients that help nourish human embryo cells.

But they can also pass mouse viruses or other microbes to the human
stem cells, which means the stem cells could end up sickening
patients instead of curing them.

Recently, however, scientists have learnt how to grow human embryonic
stem cells without mouse cells. The new stem cell colonies, or 'cell
lines', appear ideal for use in clinical trials, scientists say.

But they remain unavailable to the vast majority of US stem cell
researchers - most of whom depend on federal grant money - because
the US policy requires scientists to work only with cells from
embryos destroyed before Aug 9, 2001.

The goal was to prevent further destruction of stored human embryos,
but it also limits researchers to cell lines tainted by contact with
mouse cells.

The White House indicated that it has no intention of changing its
position.

The advent of medically-promising cells began when researchers from
Singapore published a landmark report last year showing that human
embryonic stem cells could be maintained in culture dishes if they
were accompanied by cells from 14-week-old aborted human foetuses,
instead of mouse cells.

Then, last month, scientists at Johns Hopkins University made another
leap, showing that human embryonic stem cells could thrive in a
culture system containing adult human bone marrow cells, which
apparently secrete all the growth factors the stem cells need.

Now, many are scrambling to find other recipes that support stem-cell
growth.

But scientists receiving federal grant money are not able to study
any of the newly derived lines under the current Bush policy, because
they come from embryos donated to research after August 2001.

Opponents of the current policy said the US stands to fall behind
other countries with access to more advanced cell lines and more open
research policies. \-- LAT-WP

Two new findings

WASHINGTON - Heart failure patients who got injections of their own
bone marrow cells got better, and may have grown new heart tissue or
blood vessels, United States and Brazilian researchers reported
earlier this week.

Their findings could offer a way to treat a hopeless and deadly
condition.

'If our findings are confirmed in larger trials, this procedure could
lead to an effective treatment for severe heart failure, and perhaps
to a new form of gene therapy,' Dr James Willerson, president of the
University of Texas Health Science Center at Houston, said in a
statement.

'The patients we treated had end-stage heart failure,' Dr Willerson
said in a telephone interview. Such patients often have only one hope
of recovery - a heart transplant - and hearts for transplant are in
desperate shortage.

Dr Willerson's team wanted to see if blood stem cells found in the
bone marrow might help regenerate the heart muscle or the blood
vessels feeding the heart. Writing in the journal Circulation, the
team said the treated patients had better heart function and less
chest pain. 'Either these stem cells became new blood vessel and new
heart muscle cells, or their presence stimulated the development of
one or both,' Dr Willerson said. \-- Reuters

WASHINGTON - Baby teeth may be a source of powerful stem cells that
hold promise for nerve and brain repairs, according to research.

The versatile cells found in tissue inside the teeth may help doctors
replace lost or diseased nerve tissue, researchers said.

Stem cells, which have the ability to adapt to many functions, have
been found in adult teeth as well as in bone, blood and other
tissues, said study leader Shi Song Tao, a National Institute of
Dental and Craniofacial Research biologist.

Baby teeth, or deciduous teeth, represent a constant, renewable
source of stem cells that can be harvested easily, Dr Shi said.

Dr Shi made the discovery after his six-year-old daughter lost four
teeth earlier this year.

'I took them to the lab and found there was still some tissue
inside,' he said. 'The stem cells inside grow very well.'

\-- Bloomberg

SOURCE: The Strait Times, Singapore
http://straitstimes.asia1.com.sg/storyprintfriendly/0,1887,185246,00.h
tml?

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