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The possible capabilities utilizing stem cell research

  1. In the case of research cloning, some raise concerns, for example, that the perfection of cloning techniques for research purposes will enable the pursuit of reproductive cloning, and that efforts to obtain the thousands of eggs required for the production of cloned embryos will result in the exploitation of women who provide the eggs President's Council on Bioethics 2002, Norsigian 2005.
  2. Stem cells also exist in adults and have varying abilities to self-renew. The main use of stem cells in medicine is as a source of donor cells to be used as therapy to replace damaged or missing cells and organs.
  3. A single somatic cell or HESC can in principle though not yet in practice develop into a mature human being under the right conditions—that is, where the cell's nucleus is transferred into an enucleated egg, the new egg is electrically stimulated to create an embryo, and the embryo is transferred to a woman's uterus and brought to term. However, certain states have placed bans on the creation or destruction of human embryos for medical research.
  4. Chemical and thermal burns can result in the loss of these stem cells, as well as normal vision.
  5. Eventually, the stem cells regenerated the damaged muscle tissue, improving the rats' heart function. But an entity's having this potential does not logically entail that it has the same status as beings that have realized some or all of their potential Feinberg 1986.

If looked at from a strictly consequentialist perspective, it's almost certainly the case that the potential health benefits from the research outweigh the loss of embryos involved and whatever suffering results from that loss for persons who want to protect embryos. However, most of those who oppose the research argue that the constraints against killing innocent persons to promote social utility apply to human embryos.

  1. Conference of Catholic Bishops 2001. The Etanercept-treated mice exhibited less joint inflammation [ 44 ].
  2. In this isolated population, one in every 200 cells generated tumors upon mammary fat pad transplantation and had a similar phenotype to the primary tumor.
  3. For these investigators to avoid the charge of complicity in the destruction of embryos, it must be the case that the researchers who derived the HESCs would have performed the derivation in the absence of external demand for the cells Siegel 2004. But an entity's having this potential does not logically entail that it has the same status as beings that have realized some or all of their potential Feinberg 1986.
  4. Research in 3-D In Europe, teams in Germany and Poland are advancing the use of stem cells for developmental neurotoxicity testing.
  5. Although culture on MEF feeder cells is the standard and more traditional protocol, there are now different protocols known to successfully allow the derivation and maintenance of undifferentiated mESCs. The goal is to populate the platform with lineage-related stem cells that can be maintained at different developmental stages, beginning with the pluripotent stage and ending with functional neurons.

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. In its most basic form, the central argument supporting the claim that it is unethical to destroy human embryos goes as follows: It is morally impermissible to intentionally kill innocent human beings; the human embryo is an innocent human being; therefore it is morally impermissible to intentionally kill the human embryo.

It is worth noting that this argument, if sound, would not suffice to show that all or even most HESC research is impermissible, since most investigators engaged in HESC research do not participate in the derivation of HESCs but instead use cell lines that researchers who performed the derivation have made available. To show that researchers who use but do not derive HESCs participate in an immoral activity, one would further need to establish their complicity in the destruction of embryos.

We will consider this issue in section 2. But for the moment, let us address the argument that it is unethical to destroy human embryos. A premise of the argument against killing embryos is that human embryos are human beings. The issue of when a human being begins to exist is, however, a contested one. The standard view of those who oppose HESC research is that a human being begins to exist with the emergence of the one-cell zygote at fertilization.

An individual who is an identical twin cannot be numerically identical to the one-cell zygote, since both twins bear the same relationship to the zygote, and numerical identity must satisfy the possible capabilities utilizing stem cell research.

That is, if the zygote, A, divides into two genetically identical cell groups that give rise to identical twins B and C, B and C cannot be the same individual as A because they are not numerically identical with each other.

Ethics of Stem Cell Research

This shows that not all persons can correctly assert that they began their life as a zygote. However, it does not follow that the zygote is not a human being, or that it has not individuated.

This would follow only if one held that a condition of an entity's status as an individual human being is that it be impossible for it to cease to exist by dividing into two or more entities. But this seems implausible.

Consider cases in which we imagine adult humans undergoing fission for example, along the lines of Parfit's thought experiments, where each half of the brain is implanted into a different body Parfit 1984. The prospect of our going out of existence through fission does not pose a threat to our current status as distinct human persons. Likewise, one might argue, the fact that a zygote may divide does not create problems for the view that the zygote is a distinct human being.

There are, however, other grounds on which some have sought to reject that the early human embryo is a human being. While each of the cells is alive, they only become parts of a human organism when there is substantial cell differentiation and coordination, which occurs around day-16 after fertilization.

Thus, on this account, disaggregating the cells of the 5-day embryo to derive HESCs does not entail the destruction of a human being. This account is subject to dispute on empirical grounds.

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That there is some intercellular coordination in the zygote is revealed by the fact that the development of the early embryo requires that some cells become part of the trophoblast while others become part of the inner cell mass.

Without some coordination between the cells, there would be nothing to prevent all cells from differentiating in the same direction Damschen, Gomez-Lobo and Schonecker 2006. The question remains, though, whether this degree of cellular interaction is sufficient to render the early human embryo a human being.

Just how much intercellular coordination must exist for a group of cells to constitute a human organism cannot be resolved by scientific facts about the embryo, but is instead an open metaphysical question McMahan 2007a.

Growing Knowledge: Using Stem Cells to Study Developmental Neurotoxicity

On the standard argument against HESC research, membership in the species Homo sapiens confers on the embryo a right not to be killed. This view is grounded in the assumption that human beings have the same moral status at least with respect to possessing this right at all stages of their lives. Some accept that the human embryo is a human being but argue that the human embryo does not have the moral status requisite for a right to life.

There is reason to think that species membership is not the property that determines a being's moral status. We have all been presented with the relevant thought experiments, courtesy of Disney, Orwell, Kafka, and countless science fiction works. The results seem clear: This suggests that it is some higher-order mental capacity or capacities that grounds the right to life.

The main difficulty for those who appeal to such mental capacities as the touchstone for the right to life is that early human infants lack these capacities, and do so to a greater degree than many of the nonhuman animals that most deem it acceptable to kill Marquis 2002.

This presents a challenge for those who hold that the non-consequentialist constraints on killing human children and adults apply to early human infants. Some reject that these constraints apply to infants, and allow that there may be circumstances where it is permissible to sacrifice infants for the greater good McMahan 2007b.

Others argue that, while infants do not have the the possible capabilities utilizing stem cell research properties that ground a right to life, we should nonetheless treat them as if they have a right to life in order to promote love and concern towards them, as these attitudes have good consequences for the persons they will become Benn 1973, Strong 1997. Some claim that we can reconcile the ascription of a right to life to all humans with the view that higher order mental capacities ground the right to life by distinguishing between two senses of mental capacities: George and Gomez-Lobo 2002, 260.

According to this view, an individual's immediately exercisable capacity for higher mental functions is the actualization of natural capacities for higher mental functions that exist at the possible capabilities utilizing stem cell research embryonic stage of life. The difference between these types of capacity is said to be a difference between degrees of development along a continuum.

There is merely a quantitative difference between the mental capacities of embryos, fetuses, infants, children, and adults as well as among infants, children, and adults.

Stem Cells for Cell-Based Therapies

And this difference, so the argument runs, cannot justify treating some of these individuals with moral respect while denying it to others. But an entity's having this potential does not logically entail that it has the same status as beings that have realized some or all of their potential Feinberg 1986. Moreover, with the advent of cloning technologies, the range of entities that we can now identify as potential persons arguably creates problems for those who place great moral weight on the embryo's potential.

A single somatic cell or HESC can in principle though not yet in practice develop into a mature human being under the right conditions—that is, where the cell's nucleus is transferred into an enucleated egg, the new egg is electrically stimulated to create an embryo, and the embryo is transferred to a woman's uterus and brought to term.

Because this is a stance that we can expect nearly everyone to reject, it's not clear that opponents of HESC research can effectively ground their position in the human embryo's potential.

One response to this line of argument has the possible capabilities utilizing stem cell research to claim that embryos possess a kind of potential that somatic cells and HESCs lack.

  • A subset of mice was pre-treated with tenofovir, an antiretroviral gel;
  • Induced pluripotent stem cells iPS Somatic cell nuclear transfer in the mouse Cell fate has been manipulated experimentally for a number of years beginning with the frog more than 50 years ago;
  • As the group works to develop assays to test how chemicals affect these processes, one objective is to ensure the assays are amenable to high-throughput testing, Shafer says;
  • Scientists hope they can one day replicate their success in human patients.

An embryo can mature on its own in the absence of interference with its development. A somatic cell, on the other hand, does not have the inherent capacity or disposition to grow into a mature human being. However, some question whether this distinction is viable, especially in the HESC research context.

While it is true that somatic cells can realize their potential only with the assistance of outside interventions, an embryo's development also requires that numerous conditions external to it are satisfied.

In the case of embryos that are naturally conceived, they must implant, receive nourishment, and avoid exposure to dangerous substances in utero. In the case of spare embryos created through in vitro fertilization—which are presently the source of HESCs for research—the embryos must be thawed and transferred to a willing woman's uterus.

Some grant that human embryos lack the properties essential to a right to life, but hold that they possess an intrinsic value that calls for a measure of respect and places at least some moral constraints on their use: There are, however, divergent views about the level of respect embryos command and what limits exist on their use.

Some opponents of HESC research hold that the treatment of human embryos as mere research tools always fails to manifest proper respect for them. Other opponents take a less absolutist view. Some, for example, deem embryos less valuable than more mature human beings but argue that the benefits of HESC research are too speculative to warrant the destruction of embryos, and that the benefits might, in any case, be achieved through the use of noncontroversial sources of stem cells e.

Many, if not most, who support the use of human embryos for HESC research would likely agree with opponents of the research that there are some circumstances where the use of human embryos would display a lack of appropriate respect for human life, for example, were they to be offered for consumption to contestants in a reality TV competition or destroyed for the production of cosmetics.

But proponents of the research hold that the value of human embryos is not great enough to constrain the pursuit of research that may yield significant therapeutic benefits. Supporters of the research also frequently question whether most opponents of the research are consistent in their ascription of a high value to human embryos, as opponents generally display little concern about the fact that many embryos created the possible capabilities utilizing stem cell research fertility treatment are discarded.

Some argue that as long as the decision to donate embryos for research is made after the decision to discard them, it is morally permissible to use them in HESC research even if we assume that they have the moral status of persons. The claim takes two different forms. One is that it is morally permissible to kill an individual who is about to be killed by someone else where killing that individual will help others Curzer, H. The other is that researchers who derive HESCs from embryos that were slated for destruction do not cause their death.

Instead, the decision to discard the embryos causes their death; research just causes the manner of their death Green 2002.

Both the possible capabilities utilizing stem cell research of the argument presume that the decision to discard spare embryos prior to the decision to donate them to research entails that donated embryos are doomed to destruction when researchers receive them. There are two arguments one might marshal against this presumption.

First, one who wants to donate embryos to research might first elect to discard them only because doing so is a precondition for donating them. There could be cases in which one who chooses the discard option would have donated the embryos to other couples were the research donation option not available. The fact that a decision to discard embryos is made prior to the decision to donate the embryos thus does not establish that the embryos were doomed to destruction before the decision to donate them to research was made.

Second, a researcher who receives embryos could choose to rescue them, whether by continuing to store them or by donating them to infertile couples. While this would violate the law, the fact that it is within a researcher's power to prevent the destruction of the embryos he or she receives poses problems for the claim that the decision to discard the embryos dooms them or causes their destruction. It does not follow that all research with HESCs is impermissible, as it is sometimes permissible to benefit from moral wrongs.

For example, there is nothing objectionable about transplant surgeons and patients benefiting from the organs of murder and drunken driving victims Robertson 1988.

If there are conditions under which a researcher may use HESCs without being complicit in the destruction of embryos, then those who oppose the destruction of embryos could support research with HESCs under certain circumstances.

Research in 3-D

Researchers using HESCs are clearly implicated in the destruction of embryos where they derive the cells themselves or enlist others to derive the cells. However, most investigators who conduct research with HESCs obtain them from an existing pool of cell lines and play no role in their derivation. This view requires qualification.

In such instances, it may be that no individual researcher's plans motivated the derivation of the cells.

Stem Cells and Its Medical Potential

For these investigators to avoid the charge of complicity in the destruction of embryos, it must be the case that the researchers who derived the HESCs would have performed the derivation in the absence of external demand for the cells Siegel 2004. The issue about complicity goes beyond the question of an HESC researcher's role in the destruction of the particular human embryo s from which the cells he or she uses are derived.

There is a further concern that research with existing HESCs will result in the future destruction of embryos: Conference of Catholic Bishops 2001. This objection faces two difficulties. First, it appears to be too sweeping: Yet, no one, including those who oppose HESC research, argues that we should not support these areas of research. Second, the claim about future demand for HESCs is speculative. Indeed, current HESC the possible capabilities utilizing stem cell research could ultimately reduce or eliminate demand for the cells by providing insights into cell biology that enable the use of alternative sources of cells Siegel 2004.

While it might thus be possible for a researcher to use HESCs without being morally responsible for the destruction of human embryos, that does not end the inquiry into complicity. Some argue that agents can be complicit in wrongful acts for which they are not morally responsible. One such form of complicity arises from an association with wrongdoing that symbolizes acquiescence in the wrongdoing Burtchaell 1989. The following question thus arises: Assuming it is morally wrongful to destroy human embryos, are HESC researchers who are not morally responsible for the destruction of embryos complicit in the sense of symbolically aligning themselves with a wrongful act?

One response is that a researcher who benefits from the destruction of embryos need not sanction the act any more than the transplant surgeon who uses the organs of a murder or drunken driving victim sanctions the homicidal act Curzer 2004.

Stem Cell Research