Das Potenzialitätsargument (PA) ist das wohl wichtigste Argument der Gegner der verbrauchenden Embryonenforschung und des Schwangerschaftsabbruchs. Weil schon der frühe Embryo eine potenzielle Person sei, so das Argument, besitze er bereits den moralischen Status einer Person. Mit der Möglichkeit, aus differenzierten somatischen Zellen „ethisch unproblematische“ induzierte pluripotente Stammzellen (iPS-Zellen) zu gewinnen, schien diese PA-Problematik zumindest für die Forschung umgangen. Indessen zeigen neuere wissenschaftliche Erkenntnisse, dass auch aus pluripotenten Zellen neue Organismen erwachsen können. Der Beitrag argumentiert dafür, dass nach der Logik (...) von PA nicht nur iPS-Zellen, sondern auch die somatischen Zellen, aus denen diese entstehen, als potenzielle Personen mit Würde und Lebensrecht anzusehen wären. Aufgrund dieser Implikationen ist PA auch nicht als Argument für ein Lebensrecht von Embryonen geeignet. (shrink)

ZusammenfassungDas Potenzialitätsargument ist das wohl wichtigste Argument der Gegner der verbrauchenden Embryonenforschung und des Schwangerschaftsabbruchs. Weil schon der frühe Embryo eine potenzielle Person sei, so das Argument, besitze er bereits den moralischen Status einer Person. Mit der Möglichkeit, aus differenzierten somatischen Zellen „ethisch unproblematische“ induzierte pluripotente Stammzellen zu gewinnen, schien diese PA-Problematik zumindest für die Forschung umgangen. Indessen zeigen neuere wissenschaftliche Erkenntnisse, dass auch aus pluripotenten Zellen neue Organismen erwachsen können. Der Beitrag argumentiert dafür, dass nach der Logik von PA (...) nicht nur iPS-Zellen, sondern auch die somatischen Zellen, aus denen diese entstehen, als potenzielle Personen mit Würde und Lebensrecht anzusehen wären. Aufgrund dieser Implikationen ist PA auch nicht als Argument für ein Lebensrecht von Embryonen geeignet. (shrink)

The recent discussions about alternative sources of human embryonic stem cells , while stirring new interest in the developmental potential of the various abnormal embryos or constructs proposed as such sources, also raise questions about the potential of the derived embryonic stem cells. The data on the developmental potential of embryonic stem cells that seem relevant for ethical considerations and aspects of patentability are discussed. Particular attention is paid to the meaning of “totipotency, omnipotency and pluripotency” as illustrated by a (...) comparison of the developmental potential of three-dimensional clusters of blastomeres , embryonic stem cells, somatic or stem cells or other somatic cells. This paper focuses on embryoid bodies and on direct cloning by tetraploid complementation. Usage and patenting of these cells cannot be considered to be ethically sound as long as totipotency and tetraploid complementability of embryonic stem cells are not excluded for the specific cell line in question. Testing this poses an ethical problem in itself and needs to be discussed in the future. (shrink)

The recent discussions about alternative sources of human embryonic stem cells , while stirring new interest in the developmental potential of the various abnormal embryos or constructs proposed as such sources, also raise questions about the potential of the derived embryonic stem cells. The data on the developmental potential of embryonic stem cells that seem relevant for ethical considerations and aspects of patentability are discussed. Particular attention is paid to the meaning of “totipotency, omnipotency and pluripotency” as illustrated by a (...) comparison of the developmental potential of three-dimensional clusters of blastomeres , embryonic stem cells, somatic or stem cells or other somatic cells. This paper focuses on embryoid bodies and on direct cloning by tetraploid complementation. Usage and patenting of these cells cannot be considered to be ethically sound as long as totipotency and tetraploid complementability of embryonic stem cells are not excluded for the specific cell line in question. Testing this poses an ethical problem in itself and needs to be discussed in the future. (shrink)

In lieu of an abstract, here is a brief excerpt of the content:Direct Nuclear Reprogramming: Response to Condic, Lee, and GeorgeGerard Magill, Ph.D. and William B. NeavesWe read with great interest the response of Maureen Condic, Patrick Lee, and Robert George (2009) to our essay, “Ontological and Ethical Implications of Direct Nuclear Reprogramming” in the March 2009 issue of the Kennedy Institute of Ethics Journal (Magill and Neaves 2009). Much of their response addressed issues that are not in dispute: somatic (...) cells are not zygotes, neurons and hepatocytes are different, growth-factor signals from the trophoblast influence development of the inner cell mass, membranes derived from the trophectoderm are critically required for embryonic survival, and stem cells cannot produce a fetus “on their own.”The crucial point of disagreement deals with the fact that iPS cells are not totipotent but zygotes are. Zygotes can generate their own placental structures while iPS cells must be given them through tetraploid complementation. Condic, Lee, and George consider totipotency to be crucial to natural potentiality. We present an alternative view in our essay (Magill and Neaves 2009, pp. 28–29). Placental structures make no lasting contribution to the postnatal organism, and the equivalency of iPS cells with the inner cell mass of the blastocyst is apparent from tetraploid complementation experiments.The respondents acknowledge the following:... somatic cells can be “converted” into zygotes by the process of somatic cell nuclear transfer (SCNT) or direct reprogramming in combination with tetraploid complementation—just as sperm and egg cells can be “converted” into a zygote by the process of natural fertilization—....(Condic, Lee, and George 2009, p. 35)As the respondents recognize, different ways of manipulating cells can lead to embryogenesis: sperm and egg cells in the process of natural fertilization, the enucleated egg and an ordinary body cell in the process of somatic cell nuclear transfer, and reprogrammed skin cells and a tetraploid blastocyst in the case of induced pluripotent stem (iPS) cells. In each case, different cells are manipulated—or “converted” in the respondents’ terminology—in a process that alters their biological fate within a supportive environment facilitating embryogenesis.The developmental potential that resides in the human genome does not unfold in isolation, not even in a zygote. In all cases, whether involving a zygote or an iPS cell, interaction with a supportive environment is required to express the developmental program residing in the genome. [End Page 201]This biological reality supports what we have described as “early cellular development along the continuum of natural potentiality that can result in the formation of a fetus” (Magill and Neaves 2009, p. 30), and it presents a significant challenge to the natural potentiality argument.Gerard MagillVernon F. Gallagher Chair for the Integration of Science, Theology, Philosophy, and Law, and Professor, Center for Healthcare Ethics Duquesne University Pittsburgh, PA.William B. NeavesPresident and CEO Stowers Institute for Medical Research and Professor of Basic Medical Science University of Missouri at Kansas City School of Medicine Kansas City, MOReferencesCondic, Maureen L.; Lee, Patrick; and George, Robert P. 2008. Ontological and Ethical Implications of Direct Nuclear Reprogramming: Response to Magill and Neaves. Kennedy Institute of Ethics Journal 19: 33–40. Google ScholarMagill, Gerard, and Neaves William B. 2009. Ontological and Ethical Implications of Direct Nuclear Reprogramming. Kennedy Institute of Ethics Journal 19: 23–32. Google ScholarCopyright © 2009 The Johns Hopkins University Press... (shrink)