In November, America will vote for a new President.   The next President, whomever it is, has said he will overturn the restrictions President Bush placed on use of federal money for human embryonic stem cell (hESC) research that does not meet criteria established in 2001.   

The controversy surrounding hESC research is too much to go into here but here are 5 things you should know about the science of stem cell research, including the hESC kind.

1. There are three key areas of stem cell research: embryonic stem cells,  tissue/adult  stem cells and induced pluripotent (or “reprogrammed”) stem cells.   Around the world, these three kinds of stem cells are under intense study for possible treatments for conditions from spinal cord injuries to juvenile diabetes.   Because embryonic stem cell research is unknown territory, scientists and medical researchers hope it could bring new insight into cancer or make it possible to avoid birth defects. 

Much of the controversy has focused on embryonic stem cells.

2. Embryonic stem cells that scientists study come from early-stage embryos.  These embryos are created in fertility clinics for the purpose of fertility treatment. But for a variety of reasons, not all embryos can be used for fertility treatment.   Many of these surplus embryos, which number about 400,000 nationwide, are otherwise discarded.

The cells scientists use come from embryos just five days after fertilization. Embryos at this stage, called blastocysts, are spheres containing about 100 cells that have not yet differentiated into more specialized cells. If some of these cells are placed in a lab dish in the right conditions, they can become stem cell lines that can be maintained indefinitely in an undifferentiated state, or guided to become specific types of cells. 

Scientists want to use these embryonic cells because they have the capacity to turn into any of the 200 cell types in the body. These “master cells” promise to provide large enough quantities of specialized nerve, pancreas or other cells to effectively help patients whose own cells are not functioning.

Scientists in most states are allowed to use embryos from these clinics to create stem cell lines and develop disease therapies in their laboratories. 

3. Adult stem cells have had a lot of success also.   'Adult' stem cells does not mean they are only in adults or even just in children; they are also present in developing fetuses.   They are more specialized cells that arise from embryonic stem cells. Also known as tissue-specific stem cells, they have the ability to make one or two kinds of cells, such as blood and immune system cells, brain or muscle cells. Adult stem cells have a more limited capacity to replace themselves than do embryonic stem cells.

Decades of work with adult blood stem cells have led to successful bone marrow transplant treatments that are used today to treat people who have leukemia, lymphoma and some inherited blood disorders. Today, blood stem cells can often be isolated from the blood rather than bone marrow. 

Although scientists continue to try to expand the use of adult stem cells, so far it has been very difficult to get many types of adult stem cells to reproduce in sufficient amounts to lead to effective treatments.

4. Induced pluripotent stem cells, or iPS cells, are adult cells reprogrammed to behave like embryonic stem cells.   Recently, Japanese and American scientists have developed a third type of stem cell, which are skin cells that have been 'reprogrammed' to be similar to embryonic stem cells. 

These induced pluripotent cells (iPS) are reprogrammed using viruses, which may predispose those cells to cancer.  To date, none of the reprogrammed lines that have been used in patients.   iPS cells are an exciting discovery but it is unknown whether the reprogrammed cells can function the way embryonic stem cells do.

5. In 2001, President George W. Bush announced that federal funds may be awarded for research using human embryonic stem cells that meet approved criteria.    Bush was the first President to fund embryonic stem cell research.  

 - The derivation process (which begins with the destruction of the embryo) was initiated prior to 9:00 P.M. EDT on August 9, 2001.
- The stem cells must have been derived from an embryo that was created for reproductive purposes and was no longer needed. 

- Informed consent must have been obtained for the donation of the embryo and that donation must not have involved financial inducements.

 State and private companies not using federal funds are exempt from these restrictions.

The National Institutes of Health (NIH), as the Federal government's leading biomedical research organization, implements the President's policy. The NIH funds research scientists to conduct research on existing human embryonic stem cells and to explore the enormous promise of these unique cells, including their potential to produce breakthrough therapies and cures.

Investigators from 14 laboratories in the United States, India, Israel, Singapore, Sweden, and South Korea have derived stem cells from 71 individual, genetically diverse blastocysts. These derivations meet the President's criteria for use in federally funded human embryonic stem cell research. The NIH has consulted with each of the investigators who have derived these cells. These scientists are working with the NIH and the research community to establish a research infrastructure to ensure the successful handling and the use of these cells in the laboratory.

Sean Morrison outlines several key facts that citizens can keep in mind as they navigate through a flood of often conflicting information about stem cell research. Courtesy: University of Michigan Health System