Jump to content
Powered by

A better alternative from the perspective of embryo protection

The past weeks have seen one sensational publication after another regarding stem cell research. Karin Bundschuh of BIOPRO Baden-Württemberg asked Dr. Jens Clausen how these developments should be viewed from an ethical perspective. The bioethicist spent many years studying the status of embryos, the ethics of cloning and stem cell research.

What is your view on the recently published experiments in which American researchers enucleated oocytes, implanted the nuclei in male skin cells, and used them to clone human embryos?

From a scientific perspective, this confirms that the idea of therapeutic cloning that has been a subject of debate for years is actually possible. But as therapies using this approach are not yet in sight, I would rather refer to it as extrauterine cloning. This highlights the fact that the cloned embryo remains outside the uterus, and does not create a pregnancy. The recent experiments have dispelled initial scientific concerns that were raised by the fraud scandal involving South Korean Hwang Woo Suk. It seems that the nuclear transfer approach and stem cell research can be combined in extrauterine cloning. It is certainly an important step from a scientific perspective. However, thus far it has not been possible to extract stem cells from cloned human embryos.

And how do you see the experiments from an ethical perspective?

One central criterion for the assessment of these experiments in terms of ethics is the resulting moral status of the embryo. The transfer of the nucleus results in an embryo even when it is not fertilised. There are some who actually question the reveracity of this, but they only have to look at “Dolly” the sheep. “Dolly” is the result of nuclear transfer and was an actual sheep. What else could Dolly have been before becoming a sheep but a sheep embryo? The transfer of nuclei results in embryos. These experiments therefore do not require new ethical assessments.
This is how extrauterine or therapeutic cloning would ideally take place: The nucleus of a somatic cell would be implanted into an enucleated oocyte. This would develop into a human embryo (a blastocyst). This in turn would be destroyed for the extraction
This is how extrauterine or therapeutic cloning would ideally take place: The nucleus of a somatic cell would be implanted into an enucleated oocyte. This would develop into a human embryo (a blastocyst). This in turn would be destroyed for the extraction of embryonic stem cells, which can be used to cultivate different cell types or whole organs in a Petri dish. (Figure: Clausen)

What is the current assessment of an embryo’s moral status?

One view is that an embryo has full moral status from the very beginning of its development – whether through fertilisation or nuclear transfer – just like a human who develops in the womb and is later born. Those who hold this particular belief automatically take the stance that the use and killing of embryos for research purposes is not permissible, meaning that extrauterine cloning is basically not allowed. This was the case before the currently publicised experiments, and it remains the case now.

Then there is also the position that an embryo is nothing but an accumulation of cells without any moral status. The moral status comes into being much later, for instance when embedding into the womb or at birth. The logical consequence for someone who takes this view is that work in this area should continue – if nothing else, in the name of freedom of research. This position also remains unchanged. There are also those who represent an intermediate position. In their view, the embryo does not have the same full moral status as a human being who has been born. But they do not believe that it has no moral status at all. It is not on object that can be handled arbitrarily. Those who take this stand must acknowledge that the embryo has some kind of moral status. And whether the early embryo should be protected or not is relative to other values.

As a result, the common justification for the use of embryos in stem cell research is that they might give rise to the possibility of developing new therapies. Yet issues concerning assessment are more difficult than they appear. Besides the intended research goals, it has to be taken into account whether the pursued research goals are realistic and likely to be attained as well as what the alternatives are. Finding a way of curing people is a highly valued research goal. That is, of course, absolutely out of question. However, there has recently been a great deal of activity in the search for alternatives to “therapeutic cloning”.

Before we talk about the alternatives, I would like to ask you for your ethical assessment of the recently publicised cloning experiments.

My scientific side finds these experiments incredibly fascinating. From an ethical point of view, though, they are incompatible with the required respect for early human embryos. Not even animal experiments have resulted in proof that nuclear transfer would generate tissue-compatible cells that would not be attacked by the immune system. The attempts to clone human embryos thus express the idea that embryos are not considered worthy of protection.

Considering alternatives: Late last year, several work groups independently succeeded in “rejuvenating” skin cells, reprogramming them into embryonic stem cells. Is this better from an ethical point of view?

Dr. Jens Clausen believes that from an ethical perspective “therapeutic cloning” is not compatible with the required respect for early human embryos. (Photograph: private)
The induced pluripotency that you are referring to, which was first detected in mice and then by several laboratories in human cells as well, would essentially be – I am deliberately using the conditional – the better ethical alternative. Yet this is only true under the precondition that the procedure is therapeutically applicable. But from a research perspective this is very, very exciting. Ian Wilmut, who led the research group that cloned “Dolly”, had his reasons for discontinuing his attempts to produce embryonic stem cells through therapeutic cloning after the new results were published. He says that it is no longer necessary. Extrauterine cloning initially generates embryos that must be destroyed in order to obtain pluripotent embryonic stem cells. Yet when inducing pluripotency, researchers do not take the long route via embryos.
Skin cells can be deprogrammed directly to a pluripotent stage without the development of a cell that could mature into a full human being. From the perspective of embryonic protection, this would thus be the better alternative – and it would also be a better alternative to the process of extracting individual cells from an embryo. However, the experiments as they are currently published are not yet suitable for clinical therapies. I cannot state this too clearly.

The danger that these cells could degenerate or induce tumours in their direct vicinity is considered significant.

This is true. The method that is used to reprogramme skin cells back into a pluripotent stage and the use of retroviruses as gene shuttles could in fact induce cancer. But this is not a fundamental problem to the approach. Alternative methods for inducing pluripotency are currently being explored.

That is why some stem cell experts are already talking about the “end of human cloning research”. But how to produce cloned human embryos just so happens to be a known fact. Is it not a matter of urgency to ban the cloning of humans or reproductive cloning worldwide?

Reproductive cloning incorporates the same approach as extrauterine cloning. But its aims are different. Whoever attempts to do so, wants to bring naturally born human beings into this world instead of extracting stem cells at the embryonic stage. This is not ethically justifiable especially since animal experiments have shown that whilst reproductive cloning is possible – and that is a huge insight – it clearly results in countless deformities and slow and painful animal deaths. This is simply inconceivable as an application for human beings. Ethicists – and also scientists – are unanimous in calling for this to never happen.

Dr. Jens Clausen was interviewed by Karin Bundschuh.

29.01.08
©BIOPRO Baden-Württemberg GmbH

Further information:
Dr. Jens Clausen
University of Tübingen
Department for Ethics and History in Medicine
Schleichstraße 8
D-72076 Tübingen
Tel.: +49 (0)7071/29-78031
Fax: +49 (0)7071/29-5190
E-mail: jens.clausen@uni-tuebingen.de

Website address: https://www.gesundheitsindustrie-bw.de/en/article/news/a-better-alternative-from-the-perspective-of-embryo-protection