- What is the current federal policy on embryonic stem cell research?
- Why is legislation now necessary 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?
What is the current federal policy on embryonic 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.
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. As a result of the Bush policy, state governments such as California, Connecticut, Illinois, Maryland, Massachusetts, New Jersey, New York and Wisconsin began funding embryonic stem cell research.
Why is legislation now necessary and what is the history of the bills in Congress?
What is therapeutic cloning?The Stem Cell Research Enhancement Act (H.R. 873/S. 487) has been introduced again by long-time champions Reps. Diana DeGette (CO) and Mike Castle (DE) and Sens. Tom Harkin (IA) and Arlen Specter (PA) to ensure that a future president cannot reinstate similar restrictions.
Under this legislation, 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.
In the 110th Congress, the House of Representatives passed the bill on January 11, 2007. The Senate passed their version with strong bipartisan support, 63-34 on April 11, 2007. The Senate bill differed from the House version and included language that encourages the NIH to pursue other forms of stem cell research. The House passed the Senate’s version of the Stem Cell Research Enhancement Act, 247-176 on June 7, 2007. President Bush vetoed the bill on June 20, 2007.
In the 109th Congress, the House passed the Stem Cell Research Enhancement Act (H.R. 810) with strong bipartisan support, 238 to 194 in May 2005. The Senate approved H.R. 810 on July 18, 2006, 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.
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.
Can research on adult stem cells be substituted for embryonic stem cell research?
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.
Some scientists are exploring the possibility that adult stem cells are more flexible than previously thought. However, many questions remain about the potential of adult stem cells, and much more research is required to answer them.
Can research on amniotic stem cells be substituted for embryonic stem cell research?
Amniotic stem cells are found in the fluid that surrounds a fetus. Scientists recently 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.
Why have no treatments or cures resulted from embryonic stem cell research?
The first isolation of human embryonic stem cells was documented only nine years ago in 1998 by Dr. James Thomson. Federal funding for research on embryonic stem cells began six years ago in 2001 and is limited to a small number of stem cell lines that many scientists say are not useful for research. These lines are of limited use because they are very difficult to maintain in the lab and because mutations have accumulated in the lines so that they behave differently from newer stem cell lines. 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.
Should scientists pursue embryonic or adult stem cell research?
The scientific community agrees that both adult and embryonic stem cell research show great potential to revolutionize the practice of medicine and that both types of research should be pursued.