Breakdown of the Potentiality Principle and Its Impact on Global Stem Cell Research

Abstract

Totipotency, defined as the ability of a single cell to generate an entire individual, has traditionally served as a cornerstone to frame the moral relevance of nascent human life. This "potentiality principle" has served as an ethical reference point for shaping legal regulations for stem cell research in most Western countries. Based on heterogeneous ethical, religious, and political views, different countries cope with recent advances in mammalian cloning and reprogramming in a remarkably diverse manner. This and related issues were key topics at a recent meeting held in Berlin, Germany, on ethical aspects of stem cell research in Europe. An emerging view from this event is that international heterogeneity in stem cell politics and legislation must be overcome in order to develop this field toward biomedical application.

The context of embryonic development and its ethical relevance

“…Potentiality is not an independent property of the embryo per se, but is strongly related to and depends on the biological context [7]. An embryo in an incubator and an embryo in a uterus have a different potentiality degree, and therefore should be treated differently.…”

“…A different context creates a unique cell, by regulating its genetic expression and epigenetic status. It is not correct to state that an embryo is an independent entity with a moral status regardless of its context, since the context in which the embryo develops is essential for potentiality [7].…”

“…The fact that A (embryo) has the potentiality of becoming B (an adult human being) does not logically imply that you have to treat A as if it were B [7]. We all know of cases in which this holds valid, others in which it does not: a 10-year-old child has the potentiality of becoming an adult; but should it be given the rights and privileges of adulthood [8]?…”

“…Nonetheless, it would be false that they differ in this property from other cell systems, as it is often claimed to accord to embryo and ES cells special protection rights [7].…”

How can ethics relate to science? The case of stem cell research

“…Therefore, adult stem cells are more realistically being proposed as a possible source of material to treat the tissue of origin or closely related tissues. 28 Another aspect that is often neglected relates to the fact that research with adult stem cells may not result necessarily in applications involving transplantation of cells cultured and modified ex vivo but lead to strategies focusing on interventions stimulating resident stem cells in the body. Going back in developmental time, stem cells from the amniotic fluid and umbilical cord seem promising, 18 but, again, whether the unexpected pluripotency reported in some studies is reproducible and reliable remains an unresolved issue.…”