"Therapeutic Cloning": Alternatives and Validity

Research on the so called adult stem cells was first considered to be the primary alternative to the possible development of therapies using embryonic stem cells. For stem cells not only serve development in embryonic tissue, they also occur in developed organisms, for example in blood-forming bone marrow or the brain. If the donor and recipient in a (hitherto not yet) possible therapeutic method were to be identical, problems of immunological incompatibility could be avoided without having to fall back on the creation of embryonic stem cells. What is more, adult stem cells would appear to be less prone to degeneration through tumour formation. Yet adult stem cells are to a certain extent already differentiated, which means that they have a significantly diminished development potential compared to embryonic stem cells. In addition, adult stem cells are less abundant and therefore available only to a limited extent due to the largely unknown conditions of their cultivation and differentiation.

Since their discovery in 2006 by the Japanese stem cell researcher and doctor Shin’ya Yamananka and his team, pluripotent stem cells (iPS cells) are most of all considered as a bearer of hope for an ethically uncontroversial alternative to the research on human ES cells. Since the reprogramming of adult cells can give rise to stem cells which are genetically identical with the ones of the donor, this can offer a promising alternative to cloned ES cells especially in terms of issues of immunological compatibility.

Meanwhile, objections are raised against the application of iPS cells. It has been shown that due to epigenetic alterations the degree of similarity between ES cells and iPS cells is lower than anticipated and that the latter shows a high susceptibility for mutation. More to the latest state of the art concerning iPS cells is found under “Stem Cell Research”. In addition, successful research on iPS cells with the procedure of tetraploid embryo complementation gave rise to doubts concerning the ethical indisputability of the cell type. Using the mentioned procedure it has been shown in mice that viable clones can be generated with the aid of iPS cells. For this purpose, the German Ethics Council published an Ad hoc recommendation in September 2014.  

Rendtorff et al. (2000) and Honnefelder (2000), among others, suggest that the formation of an ethical judgement should take greater account of the question of alternative methods for obtaining human pluripotent cells and for achieving the goals pursued with "therapeutic cloning" without the generation or consumption of human embryos or totipotent human cells. The same authors also make a case for incorporating into the formation of an ethical judgement the issue of adequate validation of the therapeutic concept pursued with this approach through prior experimentation on animals.

Further information:

Rendtorff, Trutz / Winnacker, Ernst-Ludwig / Hepp, Hermann / Hofschneider, Peter Hans / Korff, Wilhelm / Knoepffler, Nikolaus / Kupatt, Christian / Haniel, Anja (1999): Das Klonen von Menschen. Überlegungen und Thesen zum Problemstand und zum Forschungsprozess. In: Forum TTN 2, 4–23 (esp. 19–21). 

Honnefelder, Ludger (2000): Ohne Alternative? In: Frankfurter Allgemeine Zeitung (18 August, 2000). 

Deutscher Ethikrat (2014): Stem cell research – new challenges for the ban on cloning and treatment of artificially created germ cells? Ad hoc recommendation. Online Version

Hermann, Ira / Heyer, Martin (2010): Wirklich Alleskönner? Bericht über Forschungsergebnisse und ausgesuchte ethische und rechtswissenschaftliche Fragen der Stammzellforschung. In: Spranger, Tade (ed.): Aktuelle Herausforderungen der Life Sciences, 159–188.

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