Breakthrough over stem cells may end need for embryos
1/7/2007 8:24:00 PM
By STEPHEN MCGINTY
SCIENTISTS have discovered a new source of stem cells that might help repair the body and sidestep the controversy over destroying embryos for research.
Using stem cells is controversial because the best source is human embryo tissue. Some campaigners argue that creating embryos for research leads to the destruction of human life.
However, scientists in the United States have grown tissue from stem cells taken from amniotic fluid. The cells, which have the potential to become almost any type of tissue, were grown into muscle, bone, fat, blood vessel and nerve and liver cells. Furthermore, they remove some of the ethical problems associated with harvesting stem cells from human embryos.
Researchers at Wake Forest University School of Medicine in North Carolina and Harvard Medical School discovered a small number of stem cells in amniotic fluid (estimated at 1 per cent). They named them amniotic fluid-derived stem (AFS) cells and said they represent an "intermediate stage" between embryonic and adult stem cells.
The cells have the same potential as embryonic stem cells and their ready availability makes them vital to research, they argued. Professor Anthony Atala, a director of the Institute for Regenerative Medicine at Wake Forest, announced the discovery: "Our hope is that these cells will provide a valuable resource for tissue repair and for engineered organs as well."
Last night, Professor Ian Wilmut of the Roslin Institute, where the world's first cloned animal, Dolly the sheep, was created, welcomed the discovery: "This is very interesting work, but we should not get too carried away. We need to confirm that they really do have as long a life-span as embryo stem cells and just how many different cell types they can form.
"But if they do prove to be equally powerful, they will be a very convenient source."
Prof Atala began his work seven years ago and said it had taken that long to verify they were true stem cells. "These cells are capable of extensive self- renewal, a defining property of stem cells," he said. "They also can be used to produce a broad range of cells that may be valuable for therapy."
Last week, British scientists said the future of research into diseases such as Alzheimer's, diabetes and motor neurone disease was in jeopardy. They want to create embryos that are part animal and part human, by taking eggs from cows or rabbits, but are waiting for approval.
At present, scientists rely on eggs left over from fertility treatment, but these are in short supply and are often poor quality.
Today's research, published in the journal Nature Biotechnology, was based on harvesting stem cells from amniotic fluid taken during amniocentesis.
That procedure examines cells in the fluid to help diagnose genetic disorders before birth. Similar stem cells were also isolated from the placenta and other membranes.
Prof Atala said a bank with 100,000 specimens taken from amniotic fluid could theoretically supply 99 per cent of the US population with perfect genetic matches for transplants.
Dr Stephen Minger, a senior lecturer in stem-cell biology at King's College in London, said: "Their findings still require a lot of replication from other groups before they can be conclusive.
"They have only shown that these particular stem cells can turn into a couple of different types of other stem cells. I would say that a hell of a lot more work is required."
HUMAN embryonic stem cells, which are created in the first days after conception, can turn into any of the more than 220 cell types that make up the human body.
Researchers are hopeful they can train these cells to repair damaged organs in need of healthy cells.
It is hoped they could be used to treat degenerative diseases such as Parkinson's and Alzheimer's, as well as heart disease and burns.
The best source of stem cells is human embryos, but many people oppose the destruction of embryos on ethical grounds.
President Bush used his power of veto over legislation for the first time in his six years in the White House to block a bill allowing stem-cell research.
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