Pluripotent stem cells (SCs) can be derived from six to seven day old human embryos – hence their name embryonic stem (ES) cells. They could be useful for scientific research and possibly for a host of therapies for degenerative diseases. Being pluripotent, once transplanted they can adapt to their environment and virtually become any type of cell and thereby repair damaged tissue.
RESPECT DUE TO A HUMAN EMBRYO
Biblical texts refer to God lovingly forming the human being in the womb: “You created my inmost self, knit me together in my mother’s womb.”(Ps 139: 13) Pope John Paul II rightly says in his Gospel of Life (1995): “The human being is to be respected and treated as a person from the moment of conception.”
Alternative ethical possibilities
ALTERNATIVE ETHICAL POSSIBILITIES
There are ethical alternatives to embryo destructive research, i.e. there are many possibilities of finding or developing stem cells of wide potentiality without involving embryo destruction. Human stem cells can be derived from umbilical cord blood, bone marrow (hematopoietic), fetal tissue, and even from the nose’s olfactory-mucosa as done by Professor Mackay-Sims of Griffith University. These are non-embryonic, more popularly known as adult stem cells (SCs). Mary Horowitz estimates that over 45,000-50,000 patients worldwide annually receive transplants of hematopoietic SCs to treat blood diseases. (Thomas’ Hematopoietic Cell Transplantation, 2004, p.9).
Recently it has been found that altered mouse body cell nuclei transferred to enucleated eggs formed pluripotent SCs. This was achieved by a gene called Nanog which encodes a transcription factor that is responsible for establishing and maintaining cells in the pluripotent state. Prior to transfer, the mouse cell nuclei were modified by manipulating them to acquire high levels of expression of Nanog. This resulted in the formation of pluripotent SCs which could be grown and multiplied in culture to produce a pluripotent SC line. The same procedure could also be done using human cells. No human embryos would be formed and none would be destroyed. The ethics of this proposal has been endorsed by 34 eminent US scientists and Catholic academics. This procedure is known as altered nuclear transfer-oocyte-assisted reprogramming. (The National Catholic Bioethics Quarterly, 2005, pp.579-83). This could result in human tailor-made treatments, without the risk of immune rejection.
In another recent study (Nature, August 2006) Robert Lanza’s team reported the successful derivation of human stem cells (hES) from 8-10 cell stage IVF embryos, claiming the embryos development was unaffected. The technique adopted is similar to that used for preimplantation genetic diagnosis (PGD). It was found that the hES cells were truly pluripotent and could be used for therapeutic applications. They believe that the biopsied cells used were not totipotent, i.e. were not embryos.
The resulting cells in culture were indeed pluripotent. But it is difficult to exclude the real possibility that a single cell from 8-cell embryos is not an embryo. The benefit of the doubt should go to human life here. In a study done by J Liu’s team (Human Reproduction 1481-1486) it was found that the percentage of live born mice from 8-cell biopsied mouse embryos from which one cell was removed , was 60 whereas for the controls (not biopsied) it was 77%.
My comment is that human embryos should not be used as a live quarry at some likely risk to their own prospects for survival. This loss of life is significant in the mouse after the removal of one cell from 8-cell mouse embryos. Presumably there would be at least a similar loss rate in 8-cell human embryos from which one cell was biopsied.
Recently Takahashi and Yamanaka produced pluripotent stem cells by introducing four key factors into mouse adult cells under specific culture conditions.[ see Cell published online 12/8 2006,printed copy 25/8] What is scientifically and ethically significant is that this new procedure by-passes the use of eggs and the creation of embryos. If trials with human cells verify that this method gives rise to pluripotent stem cells, an ethical way seems to be on the horizon for medical research and therapies without the need of human eggs, the creation and destruction of embryos and even of somatic cell nuclear transfer (cloning). This is exciting news for scientists and ethicists alike, not to mention conscientious parliamentarians. However, more research needs to be carried out on the safety of these pluripotent stem cells before therapies become available.
ETHICAL ASPECTS
People who hold that the human formative process and embryo should be given absolute moral respect cannot approve any utilitarian compromise. What is immoral in itself cannot be justified by good consequences: the end does not justify the means. Human embryos, whether conceived naturally, by IVF or by cloning, should not be created in order to be destroyed or put at risk of harm for any reason.
Utilitarian arguments in favour of using embryonic stem cells collapse once alternative ethical sources of pluripotent stem cells are found. There is no ethical justification for making laws to authorise the creation of cloned human embryos.
The ethical alternative approaches outlined above are the way forward for scientific and medical research on stem cells which would be socially advantageous and less divisive for the whole community.
Dr Norman Ford SDB
Caroline Chisholm Centre for Health Ethics,
7/166 Gipps St, East Melbourne VIC 3002
Centre website
The Centre has produced a book, Stem Cells, Science, Medicine, Law and Ethics, ed. Norman Ford SDB STL PhD and Michael Herbert BSc (Hons) Available from the Centre for $15.00 incl. GST and postage. Click here to download order form.
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Dr Ford's letter published in The Age 24/8/06:
NO NEED TO 'TORTURE' THE CLONING STATS
DAVID Rivers ("Torturing statistics until they confess", Letters, 23/8) took issue with the survey on therapeutic cloning commissioned by the Southern Cross Bioethics Institute. He thought that 51 per cent of people opposed to therapeutic cloning was high and at odds with other surveys.
Readers may be interested to know that an independent professional survey conducted by Dr Christine Critchley and Dr Lyn Turner of Swinburne University of Technology was done following focus discussion groups on stem cell research and published late in 2004. They reported that the majority (53.5 per cent) indicated they would be comfortable using left-over IVF embryos. They also found that the majority (63.4 per cent) of the Australian public do not feel comfortable with scientists cloning human embryos for research purposes.
What is important is that this survey was of informed people across Australia. Clearly, Australians, properly informed, understand what therapeutic cloning of embryos means for research — and they do not like it.
Dr Norman Ford is based at the Caroline Chisholm Centre for Health Ethics, East Melbourne.