This article appears in the May 2001edition of the Catholic Medical Quarterly
The birth of Dolly the sheep in February 1997 has precipitated the greatest bio-ethical
debate of the decade and threatens many more decades of the new millenium.
Yet what a chancy affair it was, as John McLean pointed
out at the recent Symposium in Manchester. Of the 277
cells from Dolly's 'mother' that were fused with donor egg cells,
less than 30 developed to the blastocyst stage, and out of that generation
only Dolly was born alive: the others had varying degrees
of abnormalities. So much so that Ian Wilmut, the scientist
who created Dolly, has said that the procedure is so risky that to
perform it to create a human embryo would be utterly unethical. Few embryos
created by cloning could be expected to survive for long:
those that did would be likely to suffer
from birth defects, Dr. Wilmut said in an article written with Professor Rudolph Jaenisch. an America expert on the technology, in the journal Science. Cloning they say results in gestational or neonatal development failures. At best, a few per cent of the nuclear transfer embryos survive to birth, and of those many die within the perinatal period. Even apparently healthy survivors may suffer from immune dysfunction, or kidney or brain malformations, which can contribute to death later. So, if human cloning is attempted, those embryos that do not die early may: live to become abnormal adults.
However, their opposition to reproductive cloning does not diminish their approval of research in embryonic stem cells for the repair of organs and tissues. Yet the idea of therapeutic cloning is now falling from favour. Hailed in 1999 as bringing "the greatest possible benefits," it is now receiving a careful reassessment from many experts. A recent article in Nature by Peter Aldhous (April 5th) states that, aside from the problem with the supply of human egg cells, and ethical objections to any therapy requiring the destruction of human embryos, many researchers doubt whether it will be efficient enough to be commercially viable. It has. been labelled as 'astronomically expensive'. Although there has been great emphasis on the therapeutic advances possible in the future from this source, its hazards and limitations have not been adequately presented. A major disadvantage is that, if the embryonic stem cells do not come from the patient's own cells, the problem of rejection remains. In most tissues grafts grown from foreign stem cells would be quickly rejected. A possible solution to this would be the use of immunosuppressive drugs; but in the long term these may contribute to an increased risk of infection and cancer.
In a remarkably unnoticed sentence in the Chief Medical Officer s Report, it was stated that 'In the long term the scientific view is that it will be possible to reprogramme adult cells to make them behave like stem cells with the full potential of embryonic stem cells but without the morally more contestable need to create an embryo'. His opinion must be viewed alongside the acknowledgement of the Parliamentary Secretary of State for Health that it could be 30 years before any benefit from these experiments might be seen. "We do not know how long it will take" she admitted. Why then this unseemly haste to destroy embryos when the adult human cell route is becoming more promising?
In our last issue we outlined some of developments in the research on adult stem cells. Since then many reports of fundamental advances have appeared but none more exciting than that from Dr. Abuljadayel now working in Cambridge. Trying to destroy white blood cells by using a particular antibody, she forgot to add one ingredient to the mixture. The result was not dead cells but cells transformed into stem cells. She calls the process retro-differentiation: a reversal of the normal process by which immature stem cells differentiate to become normal mature adult cells. Professor Adrian Newland of the Royal Hospital Medical School said he had repeated her experiments with the same results. Naturally more work is necessary before clinical trials commence in leukaemia. Dr. Abuljadayel says that blood would be taken from the patient and treated to create a population of new stem cells, a process that takes only a few hours.
In a recent issue of The Economist (April 14th) an article entitled 'The Politics of Genes: America's next ethical war' points out that politicians and regulators in America are floundering as they try to understand the immense implications of genetic science. As it has the most advanced biotech industry and as some of these ethical questions overlap with the tortured abortion debate, America is likely to be the debate's rnost important battle ground. The article comments that the politicians and regulators seem almost completely unprepared for what is about to hit them.
Congress has generally stayed almost entirely clear of baby-making technology. A National Bioethics Advisory Commission gives advice to the president, but, it says, there is no formal overseer of the subject such as Britain's HFEA. This surely over estimates the objectivity of the latter organisation. The HFEA is in favour of human cloning for medical research. The authority includes strong representation from the test tube baby industry, and its membership is open only to those who agree to sanction destructive experiment on embryos.