| Cloning and Stem Cell Research Read full text Summary Objectives. To provide an update on the scientific advances in stem cell research since 1999 and present recommendations.
Data Sources. Literature searches were conducted in the MEDLINE database for English-language articles published between 1998 and April 2003 using the search term stem cells in conjunction with human and cloning. The Council on Scientific Affairs (CSA) report, Cloning and Embryo Research (CSA Report 7, A-99), was used to identify references prior to 1999. The World Wide Web was searched for articles relating to stem cell research. Scientists from biotechnology companies involved in adult (OsirisTherapuetics, Baltimore MD) and embryonic (Geron Corporation, Menlo Park, CA) stem cell research were also consulted to gain an industry perspective on this technology.
Results. Stem cells hold tremendous promise for treating a wide variety of human diseases as well as answering some basic biological questions regarding development. There are 2 sources of human embryonic stem cells: embryonic stem (ES) cells isolated from the pre-implantation embryo (blastula) and embryonic germ cells isolated from the genital ridge of the post-implantation embryo (fetus). Animal models provide strong evidence that stem cells can be successfully transplanted into target tissue and functionally integrated into existing systems, supporting the potential of these cells for regenerative therapy. Somatic cell nuclear transfer (SCNT) enables the generation of stem cells that are specifically tailored for an individual. The technique involves removing the nuclear material from a donor oocyte (enucleation) and replacing it with the nucleus from a somatic cell (nuclear transfer). SCNT technology is also being utilized in more basic research applications to understand molecular and cellular events underlying human diseases. However, recent legislation restricting the use of human embryos in research has limited access of U.S. laboratories to human ES cells. Generation of additional human ES cell lines via technology such as SCNT is still possible in laboratories not using federal funding but pending legislation would criminalize this type of research as well as prevent importation of cell lines developed outside this country. There is fear that much of the work conducted on human stem cells will shift to other countries if federal legislation is approved banning the generation of new ES cells in the United States. Recent studies have demonstrated that stem cells also exist in many types of adult tissue. One of the main questions surrounding adult stem cells is whether they are truly pluripotent like their embryonic counterparts or have a more limited potential (multipotent). While adult stem cell plasticity remains controversial, their possible use in repairing diseased tissue remains promising. It is anticipated that human stem cells will one day play a major role in preventing and alleviating human disease. The question of whether adult or ES will have a greater impact in regenerative medicine remains to be answered.
Conclusions. Advances in stem cell research continue at a rapid pace. These developments continue to support the potential use of human stem cells in clinical applications, although significant hurdles remain before they will be in widespread use. Thus, the use of multipotent stem cells in biomedical research, including adult and cord blood stem cells, should be supported. The use of SCNT technology for regenerative medicine (therapeutic cloning) should also be supported while the use of this technology for the specific purpose of producing a human child (reproductive cloning) should not. However, ethical considerations should be acknowledged and evaluated as research in SCNT technology proceeds. Federal funding to support research involving human pluripotent stem cells should be encouraged. Previous conflicting AMA policies should be rescinded in favor of a new policy reflecting the above views. RECOMMENDATIONS The following statement, recommended by the Council on Scientific Affairs, was adopted by the AMA House of Delegates as AMA policy at the 2003 AMA Annual Meeting: The 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. (Policy)
Also see the AMA's Genetics and molecular medicine Web site.
CSAPH home page
Reports by topic | 
