Sunday, January 07, 2007
A major breakthrough in stem cell science could quell the controversy surrounding the cutting-edge medical research, it was revealed.
Scientists have shown for the first time that amniotic fluid is a rich source of stem cells, suggesting the powerful cells can be ethically harvested. Stem cells are hugely important in the hunt for new treatments for conditions such as Parkinson's disease, Alzheimer's, multiple sclerosis, heart disease and strokes. Blank cells, capable of turning into different types of tissue, they are seen as a repair kit, with the potential to regenerate damaged parts of the body.
Embryonic stem cells - plucked from an embryo in the first days of life - are more versatile than those gleaned from adults as they are capable of turning into virtually any form of cell. However, research on embryonic stem cells is mired in controversy, as extraction of the cells lead to the death of the embryo - and protests that human life, even in its earliest stages, is being sacrificed in the interests of medical research.
Now, US researchers have shown that amniotic fluid could provide an alternative - and more ethically acceptable - source of stem cells. They found that human stem cells, shed by the unborn baby into the surrounding amniotic fluid, can be coaxed into turning into muscle, bone, fat, blood vessel, nerve and liver cells in the lab. When the nerve cells were transplanted into mice with a degenerative brain disease, they grew and repopulated the diseased areas. Bone and liver cells also functioned well, the journal Nature Biotechnology reports. In addition to being easily obtainable, the cells can be grown quickly in large quantities.
Although stem cells have been extracted from amniotic fluid before, this is the first time they have been shown to have such broad potential. Researcher Professor Anthony Atala, of Wake Forest University in North Carolina, said: 'These cells are capable of extensive self-renewal, a defining property of stem cells.
'They can also be used to produce a broad range of cells that may be valuable for therapy.
'Our hope is that these cells will provide a valuable resource for tissue repair and for engineered organs as well.'
The scientists also showed that the same cells are found in the placenta. However, stem cells taken from the umbilical cord are much harder to grow and so not so useful. The amniotic fluid - which would otherwise have been discarded - was taken from pregnant women for amniocentesis, a test commonly used to detect Down's Syndrome and other genetic conditions in the unborn baby. In the future, the cells could be collected after amniocentesis tests or from the placenta when it is expelled after the birth of the baby. They could then be banked until needed later in life either by the individual or by others.
Prof Atala said: 'In the future, banking of these stem cells may provide a convenient source for both therapy in later life and for matching of donor cells with recipients.'
Professor Malcolm Alison, a stem cell expert from the University of London, said the researchers had found a new, ethically-acceptable source of stem cells that are at least as versatile as the much-feted embryonic stem cells.
'It is a readily available source and an attractive source that would otherwise be thrown away,' said Prof Alison. 'They appear to be at least as malleable as embryonic stem cells but without all the ethical baggage.'
Reproductive ethics campaigner Josephine Quintavalle said:'The extras of childbirth have wonderful life-giving potential,' she said. 'We need to outline to the public that these cells can be obtained ethically, without any sacrifice of embryos.'
Paul Tully, of the Society for the Protection of Unborn Children, said it was wrong to invest so much time and hope in embryonic stem cell research,' he said. 'It is entirely unreasonable to suggest that the only possible treatment offers hope to someone with Parkinson's disease, motor neurone disease or other conditions,' he said.
'There are many avenues of stem cell research apart from embryonic stem cells which are proving very exciting and have great possibilities.'
Jim Dobbin, chairman of the All-Party Party Pro-Life Group, said he would welcome the use of stem cells from the amniotic fluid, provided they could be extracted without harming the unborn baby. However, other scientists cautioned that more work has to be done to establish the true potential of these stem cells. Professor Stephen Minger, a stem cell expert from King's College London, said that while it would be useful to have other sources of stem cells, there would always be a place for embryonic stem cells in research. 'This isn't a way of saying we don't need embryonic stem cells,' he said. 'This is interesting work but it needs to be reproduced on a large scale.' He added that it is unclear whether the cells would still be of use after being stored for a long period.
Stem cell research offers hope for treating and curing a host of conditions. Powerful opponents of embryonic stem cell research include the Vatican and George Bush. President Bush, who has banned government funding of stem cell research in the US, is said to view the use of embryonic stem cells as 'murder'.
Vetoing funding, he said: 'It crosses a moral boundary that our decent society needs to respect.'
However, the work has also attracted much praise with actor Michael J Fox, who suffers from Parkinson's disease campaigning for politicians who support research on human embryos. And, in the last few days of his life, Superman actor Christopher Reeve recorded an advert which stated stem cells were 'the future of medicine'.
Last month, it emerged that London doctors are about to start injecting heart attack patients with stem cells in bid to repair damaged muscle damaged during the attack. Also in recent weeks, British scientists have revealed they have grown a mini-liver - a tiny bundle of liver cells - from stem cells and used stem cells to restore the sight in blind mice.
Last week, UK researchers warned that stem cell research aimed at finding cures for a range of crippling diseases could be jeopardised because of government plans to outlaw the creation of stem cell-rich part human, part animal 'chimera' embryos.