Stem cells are undifferentiated cells with the potential to develop into most of the 220 kinds of cells in the human body. Stem cells serve as a natural repair system, replenishing other cells as long as the person or animal is still alive. When a stem cell divides, each new cell could either remain a stem cell or become another type of cell, such as a muscle cell, brain cell, liver cell, etc. Stem cells are important for living organisms for several reasons. In the three - to five-day-old embryo, a blastocyst, stem cells divide and become the various cell types that make up the heart, the lungs, and other tissues of the human body. In some adult tissues, bone marrow, muscle, and the brain, discrete populations of adult stem cells divide and replace cells lost through normal wear and tear, injury, or disease.
Scientists discovered how to obtain or to derive stem cells from early mouse embryos more than 20 years ago. Many years of research led to the breakthrough, in 1998, of how to isolate stem cells from human embryos and grow those cells in a laboratory. The embryos used in these studies were created for the purpose of overcoming infertility in women through in vitro fertilization. Once the embryos were no longer needed, the donor consented to donate the remaining embryos for research.
Currently, scientists conduct research on both embryonic stem cells and adult stem cells. Scientists hypothesize that stem cell research may, some time in the future, become the basis for new treatments for diseases such as Parkinson’s, diabetes, and heart disease. It may also become possible to use stem cells to screen new drugs and toxins and to understand the origins of the various types of birth defects.
The research on embryonic stem cells has generated a great deal of public debate. The Catholic Church, the great majority of pro-life organizations, and many individual citizens expressed ethical concerns about the use of embryos in research. Extracting the stem cells kills the embryo, which these organizations and individuals consider to be murdering the embryo for research purposes. The controversy became a national issue as politicians debated whether to allow federal funding of embryonic stem cell research. On August 9, 2001, President George W. Bush put forward a compromise solution. Federal funds could be awarded for research using embryonic stem cells under certain criteria. Deriving the embryonic stem cells, including the destruction of the embryo, had to take place before August 9, 2001. The embryonic stem cells must have been derived from an embryo created for reproductive purposes that was no longer needed, and the donors must have given their informed consent for the donation of the embryo, with the further stipulation that the donation did not involve any financial inducements. Under the Bush criteria, no federal funding would be awarded for any research that involved destroying an embryo; federal funding would only be allowed to finance research on already existing lines of embryonic stem cells.
Under the Bush administration policy, embryonic stem cell research went forward using the 78 existing lines of stem cells whose embryos had already been destroyed. That policy ran into a problem in just a few years. The scientists involved in stem cell research began developing culture conditions that were much better and safer than the original culture conditions under which the existing embryonic stem cell lines had been developed. At the same time, more and more clinically relevant lineages were being developed, although these cells were not ready to put into patients. That meant any cells derived from the original cell lines, which might be put into patients if the scientists performed a number of safeguards, would not be the safest cells to use on a patient. No matter how much testing the scientists might do, they might miss something. If the stem cells had been derived from lines developed from day one under completely defined conditions, those cells would have a higher level of safety for use in patients. As scientists got closer to developing stem cell lines under completely defined conditions, some prominent Republicans as well as Democrats began pushing for a change in federal policy. The lack of movement at the federal level led the states to begin funding embryonic stem cell research themselves.
In the November 2, 2004, general election, California voters approved Proposition 71, which provided $3 billion to fund stem cell research in the state without the limits imposed by the Bush administration. Four other states, Connecticut, Illinois, Maryland, and New Jersey, followed California’s lead and approved state-funded stem cell research programs, although at significantly lower monetary levels. It remains to be seen how much of an impact the state initiatives will have. In the United States, public policy allows state and private funding for research. The reality is, the federal government, through the National Institutes of Health, provides the funding that drives basic research and research into new therapies. In 2005 the House OF Representatives enacted a bill allowing embryonic stem cell research on stem cells derived from embryos at in vitro fertilization clinics, the vast majority of which would otherwise be discarded. The Senate enacted the bill on July 18, 2006. In spite of the strong bipartisan support for the bill, Bush rejected the bill with the first veto of his presidency on July 20, 2006. The Congress failed to override the President’s veto later that same day.
Opponents of embryonic stem cell research supported the president’s veto, arguing they were in favor of stem cell research, just not embryonic stem cell research. According to scientists doing research with stem cells, the problem with this solution is that, while you might find an adult stem cell that might work for a particular application, the ability to sustain the making of all the various types of differentiated human cells is limited to embryonic stem cells. That does not mean that embryonic stem cell research will lead to cures for various diseases. The real potential of embryonic stem cell research is in the realm of basic science. There may be some transplantation-based therapies to come out of this research, but even if there are none, many scientists think embryonic stem cell research is extraordinarily important. It is expected to become a pervasive research tool for understanding the human body. And that will lead to knowledge that could spark the development of new drugs or other treatments to cure a disease such as Parkinson’s.
The difficulty for scientists is that embryonic stem cell research has become part of a political and social debate rather than a scientific debate. Scientists see embryonic stem cell research as providing a more useful model to answer the questions they have about various diseases. The knowledge gained from that is just as likely to be applied to adult stem cells as to embryonic stem cells. In 2009 President Barack Obama signed an executive order that removed certain restrictions on federal funding for human stem cell research. This debate shows no signs of resolution in the immediate future.
Further reading: National Institutes of Health. Stem Cell Information. Available online. URL: Http://stemcells. nih. gov/. Accessed January 8, 2009.
—Stephen E. Randoll
World History
