However, most of those who oppose the research argue that the constraints against killing innocent persons to promote social utility apply to human embryos. Thus, as long as we accept non-consequentialist constraints on killing persons, those supporting HESC research must respond to the claim that those constraints apply to human embryos.
Advanced Search Abstract The use of human embryos for research on embryonic stem ES cells is currently high on the ethical and political agenda in many countries. Despite the potential benefit of using human ES cells in the treatment of disease, their use remains controversial because of their derivation from early embryos.
There are several reasons for this. To date, most embryos used for the establishment of hES cell lines have been spare embryos from IVF, but the creation of embryos specifically for deriving hES cells is also under discussion. The UK has been the first to pass a law governing the use of human embryos for stem cell research.
The European Science Foundation has established a committee to make an inventory of the positions taken by governments of countries within Europe on this issue European Science Foundation, In order to discuss the moral aspects of the isolation and use of hES cells, which is the aim of the present article, it is first essential to understand exactly what these cells are, where they come from, their intended applications and to define the ethical questions to be addressed.
What are embryonic stem cells? Broadly speaking, two types of stem cell can be distinguished: In humans, hEG cells were first established in culture inshortly after the first hES cells, from tissue derived from an aborted fetus Shamblott et al.
In the adult individual, a variety of tissues have also been found to harbour stem cell populations. Examples include the brain, skeletal muscle, bone marrow and umbilical cord blood, although the heart, by contrast, contains no stem cells after birth reviewed in McKay ; Fuchs and Segre, ; Watt and Hogan, ; Weissman et al.
These adult stem cells have generally been regarded as having the capacity to form only the cell types of the organ in which they are found, but recently they have been shown to exhibit an unexpected versatility Ferrari et al. Evidence is strongest in animal experiments, but is increasing in humans, that adult stem cells originating in one germ layer can form a variety of other derivatives of the same germ layer e.
To what extent transdifferentiated cells are immortal or acquire appropriate function in host tissue remains largely to be established but advances in this area are rapid, particularly for multipotent adult progenitor cells MAPCs of bone marrow Reyes and Verfaillie, Answers to these questions with respect to MAPCs, in particular whether they represent biological equivalents to hES and can likewise be expanded indefinitely whilst retaining their differentiation potential, are currently being addressed Jiang et al.
For other adult stem cell types, such as those from brain, skin or intestine Fuchs and Segre,this may remain unclear for the immediate future. Examples in fundamental research on early human development are the causes of early pregnancy loss, aspects of embryonic ageing and the failure of pregnancy in older women where genetic defects in the oocyte appear to be important.
A second category might be toxicology, more specifically research on possible toxic effects of new drugs on early embryonic cells which are often more sensitive than adult cells drug screening.
The most important potential use of hES cells is, however, clinically in transplantation medicine, where they could be used to develop cell replacement therapies. It is unfortunate that sensational treatment in the media, which implied the generation of whole organs from hES cells, initially left this impression so that the more realistic view emerging is already a disappointment to some patient groups.
There are, at least in theory, various sources of hES cells. In most cases to date, these have been spare IVF embryos, although IVF embryos have been specifically created for the purpose of stem cell isolation Lanzendorf et al. This option is purported to be the optimal medical use of hES technology since the nuclear DNA of the cells is derived from a somatic cell of a patient to receive the transplant, reducing the chances of tissue rejection see Barrientos et al.
It is of note that the oocyte in this case is not fertilized, but receives maternal and paternal genomes from the donor cell nucleus. Since by some definitions an embryo is the result of fertilization of an oocyte by sperm, there is no absolute consensus that nuclear transfer gives rise to an embryo see below.
Growth of the cell lines over extended periods and in some cases under defined conditions Xu et al. In addition, research will be required on how to deliver cells to the appropriate site in the patient to ensure that they survive, integrate in the host tissue and adopt appropriate function.
These are the current scientific challenges that will have to be overcome before cell therapy becomes clinical practice; the problems are common to both hES and adult stem cells.
The efficiency of establishing embryonic stem cell lines from nuclear transfer embryos is currently unknown, but expected to be lower than from IVF embryos. Ethical exploration In the following section, the status of hES cells is first considered.
Should they be considered equivalent to embryos or not? What, then, is the status of the individual cells from the ICM once isolated, and the embryonic stem cell lines derived from them?
Commentators who, against this background, regard hES cells as equivalent to embryos, apparently take recourse to the opinion that any cell from which a human being could in principle be created, even when high technology micromanipulation would be required to achieve this, should be regarded as an embryo.
It is therefore unreasonable to regard hES cells as equivalent to embryos.
Between these extremes are various intermediates. Differences of opinion exist on the weight of these arguments how much protection does the embryo deserve? In view of the fact that up to 14 days of development, before the primitive streak develops and three germ layers appear, embryos can split and give rise to twins or two embryos may fuse into one, it may reasonably be argued that at these early stages there is in principle no ontological individuality; this limits the moral value of an embryo.
The precise implications of this moral difference for the regulation of the instrumental use of embryos is, however, beyond the scope of the present article. The international debate focuses on defining these conditions.
Ethics of using surplus IVF embryos as a source of hES cells Possible objections are connected to the principle of proportionality, the slippery slope argument, and the principle of subsidiarity.
Opinions differ on how this should be interpreted and made operational.The essays address the ethics of stem cell research from a variety of viewpoints. The first essay by Katrien Devolder and John Harris argues that our view of embryos is ethically inconsistent.
This inconsistency is evident in the example of identical twins, which result from splitting of the early embryo. The Importance of Stem Cell Research - Stem cell research is a topic almost everybody in the world has a viewpoint on.
Many view the issue of stem cell research and stem cell therapy as morally wrong and a crime against humanity, others view the study of stem cells as the next step in modern science. Research Papers on the ethics of stem cell research argue that as technology becomes more refined, the ethical questions raised by the technology become more persistent and more pervasive.
When the discovery of stem cells was first reported in the literature, the. Stem Cell Research Pros and Cons – Biotech/Biomedical – attheheels.com – Debates over the ethics of embryonic stem cell research continue to divide In November the first published research paper reported that stem cells could .
In November the first published research paper reported that stem cells could be taken from human embryos. Subsequent research led to the ability to maintain undifferentiated stem cell lines (pluripotent cells) and techniques for differentiating them into cells specific to various tissues and organs.
Stem cell research and ethical dilemmas: How far have we.