- What is the current federal policy on embryonic stem cell research?
- Why is legislation important and what is the history of the bills in Congress?
- What is therapeutic cloning?
- What is reproductive cloning?
- Can research on adult stem cells be substituted for embryonic stem cell research?
- Can research on amniotic stem cells be substituted for embryonic stem cell research?
- Why have no treatments or cures resulted from embryonic stem cell research?
- Should scientists pursue embryonic or adult stem cell research?
On March 9, 2009, President Barack Obama lifted the restrictions on federal funding for embryonic stem cell research imposed by President George W. Bush. Prior to President Obama's Executive Order, only the embryonic stem cell lines in existence before August 9, 2001 were eligible for federal research funding.
On July 9, 2009, the National Institutes of Health published its guidelines for the use of stem cells in extramural NIH-funded stem cell research. These established a procedure and policy for the NIH funding of this research intended to ensure responsible and ethical use of all cell lines, including human embryonic stem cells. As a result of this policy change, forty human embryonic stem cell lines have been approved for use in federally-funded research as of December 15, 2009.
Federal research funding is important to all basic scientific research, such as stem cell research. Private investors are reluctant to invest in research that is not likely to produce a profit in the short-term.
The Executive Order signed by President Obama in March 2009 accomplished a goal that congressional champions and advocates worked toward for many years. As outlined in this section, there is a history of bipartisan support for increasing federal funding for embryonic stem cell research that was not supported by the previous presidential administration.
Legislative action will be necessary to make the current policy immune to Executive Order in the future.
The 111th Congress
March 2009: President Barack Obama lifted restrictions on federal funding for embryonic stem cell research by Executive Order.
February 2009: The Stem Cell Research Enhancement Act of 2009 (H.R.873) was introduced and sent to committee.
The 110th Congress
September 2008: The Stem Cell Research Enhancement Act of 2008 (H.R. 7141) was re-introduced and referred to the House Subcommittee on Health.
June 2007: The House passed the Senate's version of the Stem Cell Research Enhancement Act, 247-176. President Bush vetoed the bill on June 20, 2007.
April 2007: The Senate passed their version The Stem Cell Research Enhancement Act (S. 5) with strong bipartisan support, 63-34. The Senate bill differed from the House version and included language that encouraged the NIH to pursue other forms of stem cell research.
January 2007: The House of Representatives passed The Stem Cell Research Enhancement Act (H.R. 3), 253-174. This allowed federally funded researchers could use all stem cell lines derived from embryos originally created for in vitro fertilization and that would otherwise be discarded, regardless of the date they were derived. Donors would be required to provide written informed consent and would not receive any compensation.
The 109th Congress
July 2005: The Senate approved H.R. 810, but President Bush swiftly vetoed the bill the following day, sending it back to Congress. When the House voted on the bill, a majority (235-193) voted in favor of the bill, but the two-thirds needed to override the veto was not reached.
May 2005: The House passed the Stem Cell Research Enhancement Act (H.R. 810) with strong bipartisan support, 238 to 194.
Therapeutic cloning is the use of cloning technology in the search for new treatments and cures for diseases and disabilities. The genetic material or DNA is removed from an unfertilized egg and replaced with the genetic material of an adult somatic cell (e.g., skin cell). Stem cells that genetically match the adult somatic cell donor can be derived from this process. See graphic.
Once stem cells have been obtained, they can be induced to develop into specific types of cells or tissues. Since these specialized cells or tissues genetically match the adult somatic cell donor, they can be transplanted into the donor with little or no chance of the body rejecting them. Scientists also hope to use stem cells derived from therapeutic cloning to better understand how cells behave throughout their lifespan and how disease develops.
Reproductive cloning is the use of cloning technology to produce a child. The genetic material of an adult somatic cell is transplanted into an unfertilized egg that no longer has its own genetic material. Theoretically, the modified egg would then be transferred to the uterus with the expectation that it would develop into a child. Without implantation in the uterus, there is no potential of the modified egg becoming a complete organism.
Adult stem cells are multipotent, which means that they can become only a limited number of types of tissues and cells in the body. For example, adult blood-forming stem cells (found in bone marrow) have only been used successfully to treat blood-based diseases such as leukemia and lymphoma. Embryonic stem cells have greater potential to treat a wider variety of diseases because they are pluripotent, which means that they can become almost all types of tissues and cells in the body.
Adult stem cells are found in small quantities in adult tissues and umbilical cord blood, and scientists think they do not have the same capacity to produce diverse tissues or multiply as embryonic stem cells. If a patient receives an adult stem cell transplant from a donor, the patient's body might reject it-a problem that researchers anticipate could be overcome with therapeutic cloning. Adult stem cells may have more genetic abnormalities, which occur naturally during the aging process and with exposure to harmful agents.
In 2007, researchers first reported the development of induced pluripotent stem cells (iPS cells), adult cells that have been genetically reprogrammed to an embryonic stem cell-like state. These cells are already useful tools for drug development and modeling of diseases, and scientists hope to one day use them in transplants. Many questions remain about the potential of iPS cells and other adult stem cells, and much more research is required to answer them.
Amniotic stem cells are found in the fluid that surrounds a fetus. In 2007, scientists showed that they can be induced to create more cell types than previously thought. However, the author of the study himself said that his research is not intended as a replacement for embryonic stem cell research. Rather, embryonic stem cells and amniotic stem cells will likely be useful for different therapies, thus broadening the potential for these cells.
The first isolation of human embryonic stem cells was documented in 1998 by Dr. James Thomson. Federal funding for research on embryonic stem cells began in 2001 and was until recently limited to a small number of stem cell lines that many scientists deemed not suitable for research. A new treatment or cure typically takes many years to develop because scientists and doctors must ensure that it works and is safe.
Adult stem cells from bone marrow are a great example of the long and arduous process of developing a new treatment or cure. Bone marrow was first identified as a possible treatment for leukemia in the early twentieth century, and the first bone marrow transplants were attempted in the late 1950s. At first, the only successful transplants were between identical twins. It took scientists a decade to discover how to perform transplants between siblings who were not identical twins, and it was not until 1973 that bone marrow from an unrelated donor was used successfully for a transplant. Today, scientists and doctors are continuing to develop new treatments that are the result of research that started one hundred years ago.
In January 2009, the U.S. Food and Drug Administration approved the first U.S. clinical trial to test an embryonic stem cell therapy, signaling progress in this area.
The scientific community agrees that adult, iPS and embryonic stem cell research show great potential to revolutionize the practice of medicine and that all types of stem cell research should be pursued.