Report of Council on Scientific Affairs: Stem Cell Research

CSA Report 3-A-04

Subject: Stem Cell Research

Presented by: O. Edwin McClusky, MD, Chair

Referred to: Reference Committee on Science, Education, and Public Health  

Stem cells are a distinct population of cells that have two unique characteristics: long-term survival through self-renewal and the ability to change into any specialized cell.  Although it seems logical that such cells should exist, they were discovered only 20 years ago.  Because of their exceptional abilities, stem cell research is one of the most exciting areas of current medical investigation.  Stem cells have the potential of being used to replace diseased or damaged tissue and thus treat disorders such as diabetes, Parkinson's and cardiovascular disease.  Through genetic manipulation, stem cells can be used to deliver genes or proteins in gene therapy.  At a more basic research level, stem cells can assist in understanding how organs form, why cells die, and why tissues are rejected when transplanted.

Stem cells can be derived from various sources.  The first stem cells were found in a murine tumor.  Stem cells probably exist in all human organs.  Stem cells are, of course, found in the embryo.  In most cases, to be useful in research and eventually medical therapies, these cells must be able to be grown in tissue culture, maintain genetic stability for at least eight months, and have the ability to differentiate into any organ type. Under some circumstances freshly collected stem cells may be useful without cultures. Stem cells from embryonic tissue clearly possess all of these potentials (multipotential). It is not currently known if stem cells derived from adult tissues have these potentials. 

Human embryonic stem cells are found in the inner portion of the blastocyst, a globular group of cells that has the potential to differentiate into an embryo.  Another source of multipotent stem cells is umbilical cord blood.  These cells have been used to treat hematological disorders.  Whether they have the same universal potential as embryonic stem cells is still unknown.  Yet another source of stem cells is the umbilical cord itself.  When these cells are placed into the blood stream in animal models, they appear to migrate to the brain and may become useful in treating traumatic brain injury and stroke.  Like umbilical cord blood stem cells, whether or not the stem cells from the umbilical cord have the same potential as embryonic stem cells is unknown.

As of this reporting, embryonic stem cells appear to have the most potential. There are four sources of these cells.  One source is embryonic stem cell lines that are already established.  There are currently 71 human stem cell lines approved for use in federally funded research. Only 13 of those approved are available at this time (http://grants.nih.gov/stem_cells/registry/current.htm:). A second source is from embryos that have been created by couples with reproductive problems but have not been used. A third source is the use of a technique called somatic cell nuclear transfer (SCNT).  This technique involves removing the nucleus from an egg and replacing it with a nucleus from some adult cell.  This "new cell" then forms a blastocyst from which stem cells can be harvested. This is the technique that is used in cloning.  A fourth source of stem cells involves a process called parthenogenesis. This process involves selecting eggs at a point in their maturation cycle when they still have their full complement of genes. They then are artificially stimulated to induce cell division. This technique has been successful in murine embryos but has not yet been successful in humans.

There are, therefore, multiple sources of stem cells.  The differences between these stem cells have yet to be worked out.  As of this reporting, embryonic stem cells appear to have the maximum potential.  SCNT is the preferred technique in producing embryonic stem cells because they can be administered to the donor of the nucleus without eliciting an immune response. There is no support in the scientific community for using SCNT for cloning of human beings.

If stem cells from any source other than embryos are found to have the same potential as embryonic stem cells, the use of those cells will be preferred and the use of embryonic cells reevaluated.  As of this reporting, that does not appear to be the case.  Because of the enormous potential of stem cell research, well controlled studies on all stem cells should be supported until there is a broader scientific knowledge base upon which to make future decisions.  It is clear that embryonic stem cell research is being conducted in many other countries (Feb. 12, 2004, New York Times ).  It is unfortunate for researchers in this country to have been unduly restricted as is the case with the few available embryonic stem cell lines, which does not represent a genetically diverse sample.

Despite the enormous potential that stem cell research offers, there are objections and concerns about pursuing this line of research, especially when it involves embryonic stem cells.  Such concerns are not unique to stem cell research.  Many new lines of investigation are often viewed with skepticism because they are new.  This does not mean that there are not legitimate issues that have to be addressed. The ethical considerations in stem cell research should be acknowledged and evaluated as research proceeds.

The Council on Scientific Affairs prepared this report in collaboration with the Board of Councilors Subcommittee on Bioethics. The report was vetted with the Council on Public Health, Council on Medical Education, Committee on Maternal and Child Health, Texas Transplantation Society, and the Council on Legislation, as well as several county medical societies and other individual physicians.

For those who wish more scientific and/or ethics details, please refer to the following links for the excellent work done by the AMA Council on Scientific Affairs and the AMA Council on Ethical and Judicial Affairs:

 Appendix A includes a listing of major religions and their positions on stem cell research and cloning.

Recommendation: That the following statements, amended from AMA policy, be adopted by the Texas Medical Association and the remainder of this report be filed: 

  1. Support biomedical research on multipotent stem cells (including embryonic, adult, and cord blood stem cells);
  2. Support the use of somatic cell nuclear transfer technology in biomedical research (therapeutic cloning);
  3. Oppose the use of somatic cell nuclear transfer technology for the specific purpose of producing a human child (reproductive cloning);
  4. Encourage strong public support of federal funding for research involving human pluripotent stem cells; and
  5. Will continue to monitor developments in stem cell research and the use of somatic cell nuclear transfer technology.

Relevant TMA Policy:  

280.008 Fetal Tissue Research : The Texas Medical Association supports the use of fetal tissue for research with the application of the same scientific and ethical standards that apply to other forms of human tissue research (Council on Scientific Affairs, pp 139-140, I-92; reaffirmed CSA Rep. 2-A-02).

Relevant AMA Policy:

H-140.890 Cloning for Biomedical Research: Stem cells derived from cloned human embryos resulting from somatic cell nuclear transfer technology are promising as a potential source of treatment in a wide range of diseases. However, much controversy arises from the necessity to destroy embryos in order to extract their stem cells for use in biomedical research. The conflict centers on the moral status of embryos, a question that divides ethical opinion and that cannot be resolved by medical science. 

(1)
While the pluralism of moral visions that underlie this debate must be respected, physicians collectively must continue to be guided by their paramount obligation to the welfare of their patients. In this light, cloning-for-biomedical-research is consistent with medical ethics. An individual physician remains free to decide whether to participate in stem cell research or to use its products. 
   
(2)
Cloning-for-biomedical-research requires appropriate oversight and monitoring. At a minimum, not only is the oversight of an institutional review board required, but also that of a regulatory body, such as the Office for Human Research Protections, to monitor progress in the field, assist in developing relevant guidelines, and ensure that the technique of cloning-for-biomedical-research is used only if uniquely promising 
   
(3)
Informed consent by subjects participating in cloning-for-biomedical-research is governed by standard principles: voluntary participation and disclosure of all relevant risks and benefits to subjects. Disclosure to the donor of the oocyte and the donor of the somatic cell also must include: (a) description of the procurement procedures specific to the donor; (b) statement of the intention to create a cloned human embryo through introduction of the somatic cell's nucleus into the enucleated egg for research purposes (and not for transfer to a woman's uterus); (c) acknowledgment that the extraction of stem cells will require the cloned embryo's destruction; (d) the intention to derive immortal cell lines from the stem cells to be used in research and possibly in therapeutic contexts; primary and secondary uses should be disclosed and individuals should be free to refuse the use of their biological materials for specified purposes; (e) potential commercial uses and patent or ownership issues (as described in Opinion E-2.08, "Commercial Use of Human Tissue").
   
(4)
The informed consent process for potential recipients of stem cells derived from cloned embryos should conform with ethical standards outlined in the Council on Ethical and Judicial Affairs' Opinion E-2.07, "Clinical Investigation" and address additional disclosures including provenance of stem cells.
   
(5)
Due to the possibilities of contamination by infectious agents from other species and damage to DNA during growth of new tissues and organs, products of cloning-for-biomedical research raise ethical concerns similar to those surrounding xenotransplantation. Therefore, the informed consent process for potential recipients of these products also should conform to Opinion E-2.169, "The Ethical Implication of Xenotransplantation." (CEJA Rep. 7, A-03)

H-460.915 Cloning and Stem Cell Research: Our AMA: (1) supports biomedical research on multipotent stem cells (including adult and cord blood stem cells); (2) supports the use of somatic cell nuclear transfer technology in biomedical research (therapeutic cloning); (3) opposes the use of somatic cell nuclear transfer technology for the specific purpose of producing a human child (reproductive cloning); (4) encourages strong public support of federal funding for research involving human pluripotent stem cells; and (5) will continue to monitor developments in stem cell research and the use of somatic cell nuclear transfer technology. (CSA Rep. 5, A-03)

D-460.990 Science, Policy Implications, and Current AMA Position Regarding Embryonic/ Pluripotent Stem Cell Research and Funding: Our AMA shall continue to monitor PSC research and update AMA policies as required with reference to advances in this field (CSA Rep. 15, I-99)

D-460.993 Support of Embryonic Stem Cell Research: Our AMA will encourage strong public support of federal funding for research involving human pluripotent stem cells. (Res. 526, A-99)

H-460.915 Cloning and Stem Cell Research: Our AMA: (1) supports biomedical research on multipotent stem cells (including adult and cord blood stem cells); (2) supports the use of somatic cell nuclear transfer technology in biomedical research (therapeutic cloning); (3) opposes the use of somatic cell nuclear transfer technology for the specific purpose of producing a human child (reproductive cloning); (4) encourages strong public support of federal funding for research involving human pluripotent stem cells; and (5) will continue to monitor developments in stem cell research and the use of somatic cell nuclear transfer technology. (CSA Rep. 5, A-03)

E-2.147 Human Cloning: "Somatic cell nuclear transfer" is the process in which the nucleus of a somatic cell of an organism is transferred into an enucleated oocyte. "Human cloning" is the application of somatic nuclear transfer technology to the creation of a human being that shares all of its nuclear genes with the person donating the implanted nucleus.

In order to clarify the many existing misconceptions about human cloning, physicians should help educate the public about the intrinsic limits of human cloning as well as the current ethical and legal protections that would prevent abuses of human cloning. These include the following: (1) using human cloning as an approach to terminal illness or mortality is a concept based on the mistaken notion that one's genotype largely determines one's individuality. A clone-child created via human cloning would not be identical to his or her clone-parent. (2) Current ethical and legal standards hold that under no circumstances should human cloning occur without an individual's permission. (3) Current ethical and legal standards hold that a human clone would be entitled to the same rights, freedoms, and protections as every other individual in society. The fact that a human clone's nuclear genes would derive from a single individual rather than two parents would not change his or her moral standing.

Physicians have an ethical obligation to consider the harms and benefits of new medical procedures and technologies. Physicians should not participate in human cloning at this time because further investigation and discussion regarding the harms and benefits of human cloning is required. Concerns include: (1) unknown physical harms introduced by cloning. Somatic cell nuclear transfer has not yet been refined and its long-term safety has not yet been proven. The risk of producing individuals with genetic anomalies gives rise to an obligation to seek better understanding of-and potential medical therapies for-the unforeseen medical consequences that could stem from human cloning. (2) Psychosocial harms introduced by cloning, including violations of privacy and autonomy. Human cloning risks limiting, at least psychologically, the seemingly unlimited potential of new human beings and thus creating enormous pressures on the clone-child to live up to expectations based on the life of the clone-parent. (3) The impact of human cloning on familial and societal relations. The family unit may be altered with the introduction of cloning, and more thought is required on a societal level regarding how to construct familial relations. (4) Potential effects on the gene pool. Like other interventions that can change individuals' reproductive patterns and the resulting genetic characteristics of a population, human cloning has the potential to be used in a eugenic or discriminatory fashion-practices that are incompatible with the ethical norms of medical practice. Moreover, human cloning could alter irreversibly the gene pool and exacerbate genetic problems that arise from deleterious genetic mutations, resulting in harms to future generations.

Two potentially realistic and possibly appropriate medical uses of human cloning are for assisting individuals or couples to reproduce and for the generation of tissues when the donor is not harmed or sacrificed. Given the unresolved issues regarding cloning identified above, the medical profession should not undertake human cloning at this time and pursue alternative approaches that raise fewer ethical concerns.

Because cloning technology is not limited to the United States, physicians should help establish international guidelines governing human cloning. (V) Issued December 1999 based of the report "The Ethics of Human Cloning," adopted June 1999.

D-460.998 Cloning and Human Embryo Research: Our AMA will support efforts to convene a conference of scientists, physicians, bioethicists, and other relevant experts to develop consensus on the scientific and bioethical issues raised by somatic cell nuclear transfer technology. (CSA Rep. 7, A-99)

Appendix A

Many religions allow the various segments of the religion to determine their unique statements. Those religions with a definite statement as an organization are listed below.

 

Religion

Supports research on cord blood and adult stem cells

Supports use of embryonic stem cells in research

Supports therapeutic cloning

Supports reproductive cloning

         

U.S. Catholic Bishops
www.usccb.org

Yes

Opposes

Opposes

Opposes

         

Orthodox Jewish
www.ou.org

Yes

Yes

Yes

Opposes

         

Reform Judaism
www.rac.org

Yes

Yes

Did not locate

Did not locate

         

Southern Baptist
www.sbc.net; www.sbcannualmeeting.org

Yes

Opposes

Yes for molecules, DNA, cells, tissues, organs

Opposes

         

United Methodist
www.umc-gbcs.org

Yes

Opposes

Opposes

Opposes

         

Episcopal
www.episcopalarchives.org

Yes

Opposes

Did not locate

Did not locate

         

United Church of Christ
www.ucc.org

Yes

Yes

Did not locate

Did not locate

Evangelical Lutheran
www.elca.org

No global statement; various synods have unique statements

Various

Various

Various

         

Islam

No central institution

Did not locate

Did not locate

Did not locate

         

Hinduism

No single authoritative

voice

Did not locate

Did not locate

Did not locate

         

Buddhism
www.buddhanet.net

Various sects

Various

Various

Various

 


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