REVOLUTIONARY medical treatments that replace damaged organs with replicas made from a patient鈥檚 own tissue or from 鈥渙ff-the-shelf鈥� tissue banks moved a stage closer this week in Britain. In a momentous decision that could catalyse similar moves in other industrialised countries, Tony Blair鈥檚 government has recommended changes to the law that would allow controversial research on human embryos.
But the British government is not ordering its own MPs to vote for the changes in the law. When the proposed legislation is presented to MPs later this year, they will be free to vote according to their consciences.
To make the spare organs, doctors would use so-called stem cells, primordial cells that can grow into almost any type of tissue. These stem cells could hopefully be grown into the tissue of choice, such as muscle, heart, liver or lung.
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鈥淥ff-the-shelf鈥� tissue could be created from mass-produced stem cells stored in tissue banks. Patients would either receive immunosuppressive drugs to stop them rejecting the graft, or cells might be tissue-typed to suit groups of patients in the way that blood groups are now.
An alternative is 鈥渢herapeutic cloning鈥�, a way of making perfectly matched organs from a patient鈥檚 own tissue by applying the technique used to create Dolly the sheep. Doctors would take a patient鈥檚 cell, from skin say, then fuse it with a donated human egg stripped of its own genetic material. The cells would divide to create an early embryo, or blastocyst, from which stem cells could be harvested (see Diagram).
The problem is that in both these cases, the stem cells come from embryos. Pro-life groups oppose such research because they believe it means killing a potential human being, even though the cells in blastocysts have not changed into specialised tissues and organs.
At present in Britain, researchers can legally experiment on embryos up to 14 days old, but only in five research categories linked to infertility. In December 1998, a panel of advisers urged the government to change the law to allow two further categories. One was therapeutic cloning; the other would allow research using the Dolly technique to treat inherited diseases of mitochondria, the energy factories of cells.
The recommendations came from a joint report by the government鈥檚 independent Human Genetics Advisory Commission (HGAC) and the Human Fertilisation and Embryology Authority (HFEA). But the government responded in May 1999 by stalling, setting up a second panel to re-examine the issue under its Chief Medical Officer, Liam Donaldson. This week, the government finally released the Donaldson report. Blair鈥檚 government is now backing in full the changes that would legalise the two new categories of embryo research. But MPs will be allowed to vote on the issue.
Some have attacked the free vote as a ploy to avoid offending opponents of therapeutic cloning, such as the Catholic Church. 鈥淚t shows lack of leadership,鈥� says Alistair Kent of the Genetic Interest Group, which represents patients with hereditary diseases. 鈥淭o put it to a free vote is to abdicate responsibility for taking control.鈥�
Others are more conciliatory. 鈥淚t鈥檚 right to say that a moral issue of this sort is put to a free vote,鈥� says Martin Bobrow, a medical geneticist at the University of Cambridge and a member of the HGAC, which originally proposed the law change.
There is also pressure for change in the US, where government researchers are banned from working on stem cells to avoid offending the pro-life lobby. The ban does not apply in the private sector, however, and calls are intensifying for government labs to be allowed to do the research to avoid monopolisation for private gain.
Within weeks, the National Institutes of Health is expected to issue guidelines allowing federal researchers to work on but not harvest stem cells from embryos. A bill passing through Congress goes further, proposing that federal money should be used both to harvest and work on stem cells.
Ironically, the bill has found support among many Republicans who are pro-lifers. Despite their stance on abortion they reject the notion that embryos left over from IVF treatment are potential human beings. They have been persuaded by personal experience with illnesses and by patients鈥� rights groups who say that it鈥檚 morally reprehensible to deny them new treatments.
Other groups, such as the United Methodist Church, oppose it on the grounds that it brings human life closer to being a commodity. A stronger argument, perhaps, is that adult stem cells might prove to be a way round the whole problem because they don鈥檛 come from embryos (see 鈥淥ld cells, new tricks鈥�). 鈥淲hy should we start opening up this entire ethical quagmire when we really don鈥檛 need to,鈥� says Gene Tarne of the Coalition of Americans for Research Ethics.
Researchers agree with this, but argue it can鈥檛 happen without research on embryos first (see 鈥淏ack to the source鈥�). Tom Okarma, chief executive of Geron in California, which has exclusive access to stem cells (see 鈥淗ighly cultured鈥�), says research would accelerate if the federal research ban was lifted: 鈥淚t鈥檚 a medical and global tragedy that this is taking so long.鈥�