Stem Cell FAQs
What are stem cells?
Stem cells have two characteristics that distinguish them from other types of cells: First, they are unspecialized cells that renew themselves for long periods of time through cell division. Second, they can become cells with special functions, such as the beating cells of the heart muscle or the insulin-producing cells of the pancreas.
Where do stem cells come from?
One type of stem cell comes from the human embryo. These are known as human embryonic stem cells. Some stem cells have been isolated from certain types of fully formed tissue. These are frequently referred to as ‘adult’ stem cells.
What are the key differences between embryonic and adult stem cells?
Embryonic stem cells have two unique qualities: 1.) They are able to develop into any of the 220 types of tissues that make up the human body. 2.) They have the ability to reproduce indefinitely in culture, which means it is possible to obtain large amounts of cells for scientific study or therapy.
Adult stem cells are found in some tissues of the body. Some have shown a capacity to be "reprogrammed" to become other types of cells. However, adult stem cells are limited in their ability to be reprogrammed and are difficult to culture in the laboratory because they have a tendency to stop dividing. Finally, adult stem cells are rare and difficult to find. Scientists have been unable to find adult stem cells in some tissues, such as the brain.
How are embryonic stem cells obtained for research?
Embryonic stem cells are obtained from excess embryos created as a result of in vitro fertilization treatments. The embryos are donated with the informed, written consent of patients who are no longer receiving treatment and who do not wish to keep the embryos.
Are embryos created for the specific purpose of scientific research?
No. In Wisconsin, the embryos that have been used for embryonic stem cell research have all been donated by patients being treated for infertility. The patients are no longer being treated and the embryos, which are frozen in storage, would otherwise be discarded.
What are the choices patients have for unused embryos?
Prior to treatment and creation of embryos for in vitro fertilization, patients are advised that it is likely there will be surplus embryos. Many embryos are created because the procedures are invasive and patients may have to undergo multiple treatments. Patients are informed of the following options for surplus embryos: 1.) indefinite storage (at the patient’s expense), 2.) donation to other infertile couples, 3.) donation for research, and 4.) discarding.
Why use embryonic stem cells when adult stem cells are available?
Embryonic stem cells have some distinct advantages over adult stem cells. Foremost are their unique qualities to become any cell or tissue in the body and to reproduce indefinitely in culture. The latter suggests that limitless cells or tissues could be made available for therapy and research. No adult stem cell has these capabilities. Moreover, embryonic stem cells provide the only window we have to the earliest stages of human development. It is at this stage of development that the stage is set for the development of chronic disease. Basic studies of human embryonic stem cells promise an understanding of the human body that could surpass any contributions the cells may make to transplant medicine.
What is therapeutic cloning?
"Therapeutic cloning" or somatic cell nuclear transfer, is a process where the nucleus of an unfertilized egg is removed and replaced with the nucleus of an adult cell, such as a skin cell. The resulting embryo is a genetic match to the donor of the adult skin cell. Cloning, in theory, could be used in two ways: for reproductive purposes or to create stem cells that can be used in therapy. Reproductive cloning in animals is difficult to accomplish and its safety is unproven. The scientific community does not support cloning for reproductive purposes. Therapeutic cloning has the potential to create stem cells that are a genetic match to a patient and would address the possibility of the body's immune system rejecting cells that have a different genetic identity. Cells that are genetically identical to a patient's would, in theory, not be recognized by the immune system as foreign cells and could thereby overcome the problem of immune rejection, an issue that frequently occurs in the transplant of donor tissues or organs. Therapeutic cloning, while promising, is not being conducted at WiCell or UW-Madison, and no such work is planned.
Given the limits on embryonic stem cell research, would it be wise to limit science to adult stem cells?
Science is an exploration of the unknown. Scientists cannot predict where the next great breakthrough will occur. No reasonable scientist would argue to limit legitimate, responsibly conducted research. An overwhelming majority of scientists, including those who work with adult stem cells, believe there is great promise in human embryonic stem cells, and that the research should not be limited.
What kind of stem cell research is occurring at UW-Madison?
More than 30 research groups involving more than 80 scientists at UW-Madison are working with human embryonic stem cells. Work ranges from the study of brain cells to treat Parkinson’s disease and ALS to studies of heart cells to treat heart disease and insulin-producing cells to treat diabetes. Scientists have found ways to transform ‘blank-slate’, or undifferentiated stem cells, into important cell lineages with therapeutic potential. For example, Wisconsin scientists were the first to turn embryonic stem cells into the critical motor neurons that may someday be used to treat ALS and other devastating central nervous system disorders. Wisconsin scientists were also the first to transform human embryonic stem cells into blood cells, work that could someday alleviate chronic shortages of blood products.
Why is UW-Madison a significant center of embryonic stem cell research?
The world’s first human embryonic stem cell lines were created at UW-Madison in 1998. The patents that govern embryonic stem cell technology are held by the Wisconsin Alumni Research Foundation, a private, non-profit supporting organization of the UW-Madison. Because of Wisconsin’s traditional strength in the biological sciences, the fact that the initial breakthrough occurred here, and the patents are held by WARF, the UW-Madison is arguably the world leader in human embryonic stem cell research.
What is happening in other states?
Discussions similar to those in Wisconsin are occurring elsewhere. California, where voters have approved investing up to $3 billion in stem cell research, is the most notable. Other states, including Massachusetts, Connecticut and New Jersey, have launched or are contemplating initiatives to bolster embryonic stem cell research. A bipartisan coalition of state legislators in New York has proposed spending as much as $100 million for stem cell research to keep the state competitive in the biotechnology arena.
What are the economic implications of stem cell research?
Like other forms of biotechnology, technology that emanates from research on embryonic stem cells has the potential to fuel Wisconsin’s economy. Companies founded on stem cell research are already beginning to emerge here. Moreover, Wisconsin now has a critical advantage in the international race to recruit and develop such biotechnology companies, given the critical mass of stem cell research at UW-Madison and advantages based on intellectual property held by the Wisconsin Alumni Research Foundation.
What are the potential consequences of restrictions on embryonic stem cell research?
If restrictions continue to be imposed on human embryonic stem cell research, the consequences will be significant. In addition to driving research from the state, the perception of Wisconsin as leader in modern biology would be severely and permanently damaged. The message to academic scientists, who now fuel a $750-million annual research enterprise at UW-Madison, would be unmistakable, and the university’s ability to compete for the best scientists and students would be compromised. Technology-based companies that might otherwise view Wisconsin as an ideal setting could reasonably question the state’s commitment to a knowledge-driven economy. Efforts to retain a highly educated workforce also would be weakened.
Where can I find a glossary of terms?
Click here to see the National Institutes of Health's comprehensive Glossary of Terms for stem cell research.
