Stem Cell Research: will science & ethics meet?
by Kate Vanskike SmithGoogle stem cell research and you’ll discover there are 13.5 million Internet pages catalogued for the subject. The topic was on ballots in a handful of states during the 2006 elections and will likely be a topic of the presidential campaigns for 2008.
Despite the fact stem cell research continues to make national headlines, it’s a debate few people feel they really understand. For the last several years, the complicated subject has centered on patients who are literally dying for medical cures and individuals who feel the moral issues surrounding potential cures simply cannot be ignored. The one thing we have all undoubtedly understood is the effort of politicians in both parties to use stem cell research to earn a few more points in the opinion polls.
The reality is, stem cell research reaches far deeper than any political rant. The fundamental stem cell debate is about you and me as individuals. What does each of us really believe about life’s origin, about the role of science in our world, about potential cures?
Fortunately, even as we contemplate those questions, alternatives are on the rise.
One of the problems in discussing stem cell research surrounds
the inaccurate use of words. Here are a few basic terms that must
be defined before further discussion.
| Stem cells - "unspecialized" or "undifferentiated" cells, not yet designated for a specific function; capable of dividing and renewing themselves for long periods; and able to produce specialized cells (called differentiation). Two types: embryonic and adult. |
Embryonic stem cells - obtained from embryos only four or five days old. They are said to be “pluripotent” – capable of producing all of the specific cell types in the body. When cells are extracted for research, the process destroys the original embryo.
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| Embryo - what is created when a sperm fertilizes an egg; the new cell has one-half the DNA of both parents. (Typically, the term “embryo” is used from the time of conception until the eighth week of pregnancy, at which time the term “fetus” is used.) |
Adult stem cells - found in developed tissues; they exist to maintain and repair the tissues in which they are found. To clarify that they are not in “adults” (people of a certain age) but in cell masses that are mature, scientists now use the term “somatic” stem cell. These cells exist in the brain, bone marrow, blood, skin and liver. They are believed not to replicate themselves until they are activated by disease or tissue injury. |
Scientific successes & struggles
Scientists around the globe feel they are on the threshold of a whole new world of possibilities—not only effective treatments, but perhaps even cures for diseases that currently threaten the quality of life for millions of people. Termed regenerative medicine, new therapies could emerge for an array of conditions ranging from age-related wasting of muscle tissue to certain types of dementia. Recent discoveries include:
- Repair of congenital heart defects. “By using embryonic stem cells to study development, some important things have been learned about congenital heart defects … stem cells may directly replace damaged/diseased tissue, but also protect tissues from disease.” (William Lensch, PhD, Science magazine, 2004)
- Reversal of Parkinson’s disease. “The loss of highly specialized dopamine-producing brain cells in Parkinson’s disease might be reversed by the infusion of new, fully functional brain cells.” (Whitehead Institute, Massachusetts Institute of Technology)
- Treatment of Alzheimer’s disease. “Human embryonic stem cells can be used to develop a sophisticated understanding of how Alzheimer’s disease develops, what its causes are, and how new therapeutic drugs might be developed. Modified stem cells can be directed to form the types of brain cells that die in Alzheimer’s disease.” (Lawrence Goldstein, PhD, University of California-San Diego School of Medicine)
And the list goes on. People suffering from diabetes, AIDS, cancer, joint and muscular diseases and even burns could potentially live longer and enjoy an improved quality of life. At last, a way to reduce the human suffering caused by disease seems to be drawing closer.
Not too close, however.
After 20 years of studying stem cells in mice, scientists have reached a point where theories must be tested on human cells. Adult (somatic) stem cells have potential, but the most promising source of answers comes from cells that have not yet fully developed—those from embryos. That’s where the controversy heats up (and where federal funding cools).
Using human embryos has stirred relentless debates about the ethics of destroying one form of life in order to benefit another. And even more basic than that is the essential question, “When does life really begin?”
Those questions are not just left for theologians and philosophers to determine. Scientists are wrangling with these issues as well, and even colleagues at the same research facility arrive at different conclusions.
At MIT’s Whitehead Institute, James Sherley, an associate professor who chooses to concentrate on adult stem cells, challenges the majority of scientific colleagues saying, “We know that embryos are alive. (With embryonic stem cell research,) we’re talking about destroying one human being for another human being’s gain.”
Rudolph Jaenisch, who heads the Whitehead human embryonic stem cell facility, is not persuaded. Yet, in hopes of quelling the ethical debate, he has forged ahead with the development of an alternative method to use stem cells without destroying something that had the potential to have a life of its own. In 2005, using stem cells from mice, he successfully used a process called altered nuclear transfer to genetically alter embryos so they are unable to implant in a uterus and become separate beings.
Dr. Jaenisch states, “Altered nuclear transfer not only works, but is extremely efficient.” He believes all the technical concerns about this approach can be overcome.
“Reprogramming cell behavior like this is a very good goal,” says Julie Biggerstaff, PhD, cytogeneticist at Sacred Heart Medical Center. “What they’re talking about, essentially, is erasing the chalkboard … using the cell’s genetic makeup, but controlling it and guiding its function so that it becomes the cell type desired.” She continues, “How that can be done is something we truly don’t fully understand and that’s why the research is so critical.”
Moral debates
The question, “When does life begin?” is an age-old debate that has surrounded hot topics like abortion. It continues to be an issue for well-meaning couples who simply want to bear and raise children, too. Those who undergo fertility treatments at in vitro fertilization clinics face the agonizing decision of what to do with all the “leftover” embryos they’ve created. Parents can choose to give embryos to other couples to gestate and bring into the world, donate them for research, or freeze them … perhaps, indefinitely.
Governmental Decisions
On August 9, 2001, President George W. Bush announced that, where human embryonic research was concerned, federal funds would only be used on existing stem cell lines “where the life and death decision has already been made.” He went on to say, “This allows us to explore the promise and potential of stem cell research without crossing a fundamental moral line by providing taxpayer funding that would sanction or encourage further destruction of human embryos that have at least the potential for life.”
At the time, it was believed that there were more than 60 existing stem cell lines around the world, available for scientific use. (A “line” develops from a stem cell that has the potential to multiply indefinitely if the right conditions are met.) Funds would be used for research on stem cells that were derived: (1) with the informed consent of the donors; (2) from excess embryos created solely for reproductive purposes; and (3) without any financial inducements to the donors.
The National Institutes of Health would be responsible for examining those stem cell lines and maintaining a registry of them. (Two years after the announcement, only 12 lines were listed on the National Institute’s of Health registry; six of those are controlled by foreign countries.) Since the President’s declaration, there have been 18 resolutions (or amendments) presented to Congress for discussion. Eleven are still under review; two were voted down; five are related to the official law regarding human embryonic stem cell research.
The Stem Cell Therapeutic and Research Act of 2005 included responsibilities of a cord blood inventory, changes to the existing cell transplantation program, development of a stem cell therapeutic outcomes database and specification of appropriations for the work ($32 million each year from 2007 to 2010).
Today, there are an estimated 500,000 frozen embryos in storage facilities throughout the United States. Those embryos could greatly expedite the stem cell research progress and, scientists hope, ultimately provide the hope patients and families are seeking. However, with the funding restrictions on embryonic research enforced by the U.S. government (see “The buck stops here”), those embryos will remain frozen.
How long can an embryo remain frozen and still have the potential to develop into a human being if implanted into a woman’s uterus? That’s a question without an answer … and another piece of the ethical puzzle. After all, many would argue, isn’t it better to use those embryos for good than to waste them?
There are countries and organizations that declare life begins once an embryo—in a uterus—is 40 days old. Other groups, like the Catholic Church, firmly believe life begins at conception—the moment the sperm has fertilized the egg—whether inside a uterus or not. The Church asserts that destroying an embryo at even just 5 to 6 days old is a “gravely immoral act.”
“The growing acceptance of embryonic stem cell research puts Catholic health care in a difficult position,” writes Ron Hamel, PhD, senior director of ethics for the Catholic Health Association, of which Sacred Heart Medical Center is a part. “The ministry is caught between its commitment to human life in all its forms, on one hand, and on the other, its commitment to healing, the relief of suffering, medical progress, and the pressures of competition and economic stability.” He adds, “The pressure to become involved in embryonic stem cell research will only increase.”
What do we believe about the origin of life? About destruction of an early life for our own gain? To what extent do we rely on science and medicine to resolve human problems?
While Catholic leaders have always wrangled with these questions, they have also come to one more issue for debate: If stem cells have already been harvested from embryos and are available for research, and Catholic hospitals were not involved in that process, would it be morally permissible for Catholic hospitals to employ those stem cells in research?
“If the Church allows the use of vaccines [made possible, thanks to research on both animal and human subjects], then it is possible the Church may someday allow this as well,” says Jan Heller, PhD, director of ethics for Providence Health & Services (Sacred Heart’s parent organization). “My belief is, under certain circumstances, it could be permissible for Catholic hospitals to be involved.”
“We have to evaluate the purpose of the research in terms of both the potential good and the potential harm,” says James Shaw, MD, ethicist at Sacred Heart. “Right now, the part of stem cell research that is not controversial is the use of non-embryonic stem cells. Undoubtedly, something very positive will come from the research of adult stem cells and then we will be faced with the question of how to support it.”
Drs. Heller and Shaw agree adult stem cell therapy (specifically, autologous or “selfdonated” cells) is the best way to go. Unfortunately, most scientists don’t believe adult stem cells hold the same potential as those from embryos. “Adult stem cells do have promise, but in more limited applications,” explains Dr. Biggerstaff. “You can’t take adult cells from blood and use them for spinal cord regeneration.”
“The tension between those who hold to Catholic beliefs (or other religious faiths) and those who want to understand early life processes will likely not go away,” she continues. “But the reality is, we’re all trying to answer the same question of when life begins. It comes down to an individual decision: can you take it on faith or do you require scientific data to back up your beliefs?”
The potential for unending philosophical debate is obvious. So long as people are asking the hard questions about right and wrong, life and death, science and religion, there will always be controversy.
Emerging alternatives
In recent weeks, scientists have reported new discoveries that show there may be additional options for research, beside the controversial embryonic sources and the more limited adult stem cells. For example, amniotic fluid from a pregnant woman’s uterus and blood from a baby’s umbilical cord are available immediately following a baby’s birth, and use of these sources has no ill effect on the life of the baby or the mother.
While these alternatives appear to be without a controversial “twist,” work with these sources is in very early stages. And while it avoids the dilemma of the embryo altogether, scientists are not yet sure these cells have the same potential as embryonic cells.
Oftentimes, when the term “stem cell therapy” is used, people confuse it with the controversial topic of stem cell research. Stem cell therapy uses stem cells from the normal bone marrow that are the parent cells to all of the normal components of blood: red blood cells, white blood cells and immune system lymphocytes. The procedure involves an “autologous” (self-donated) supply of stem cells that are reinfused back into the donor’s body.
At Sacred Heart Medical Center, stem cell therapy was introduced in 1995 as part of a clinical trial for women with breast cancer. Today, patients with blood-related cancers, such as non-Hodgkin’s lymphoma and multiple myeloma, are experiencing positive results from stem cell therapy. Some patients experience a total remission, while others have a long disease-free interval.
How does it work? A patient’s own stem cells are extracted from his bone marrow and the cells are frozen and stored at a blood center in Seattle. Patients with cancer undergo chemotherapy doses that are powerful enough to permanently damage the normal bone marrow function. When the patient’s own stem cells are re-infused into his body, they allow the bone marrow to resume normal functions.
This procedure is done at Sacred Heart, although some physicians still send patients to Seattle for it. The Inland Northwest Blood Center in Spokane currently has plans to open a lab for adult stem cell storage so local hospitals won’t have to send patients’ supplies out of the area.
The first pediatric stem cell re-infusion occurred at Sacred Heart Children’s Hospital this March.
The original intent of cord blood banking is to have self-donated blood products available if and when a baby (or his family members) need it. Despite heavy marketing to expecting parents, cord blood banking is not yet common practice since banking a baby’s cord blood currently can cost families $2,000 in start-up fees, plus $50-150 per month of storage. If hospitals and research facilities want to expand research on this stem cell supply, they face the challenge of finding alternative ways to store the supplies and to reduce costs.
In addition to research purposes, cord blood is a great source of blood products for treatment purposes and can be used as an alternative to bone marrow for stem cell therapy. In Spokane, the Inland Northwest Blood Center does not provide cord blood banking services, but will help local patients make arrangements for collection.
Scientists have already used stem cells from amniotic fluid to create muscle, bone, fat, blood vessel, nerve and liver cells in the laboratory. Anthony Atala, MD, senior researcher for the Institute for Regenerative Medicine at Wake Forest University School of Medicine, says, “Our hope is that these cells will provide a valuable resource for tissue repair and for engineering organs as well.” He believes true stem cells can be captured from the population of cells in amniotic fluid and that they represent an intermediate stage between embryonic stem cells and adult stem cells.
Research projects require time—and lots of it. It takes years to test theories and then more years to evaluate data and arrive at conclusions. Stem cell research is no different. Embryonic stem cell projects, especially with current constraints, could take decades to evolve from paperwork into real-life therapies. Adult stem cell therapies, which have existed for 40 years, still require more research to develop the kind of widespread cures scientists anticipate.
New opportunities will continue to arise, and even while they relieve some of the moral pressure surrounding this genre of research, they, too, will require time.
The problem is the unfortunate reality that people suffer while we wait.
Resources:
To read more about stem cell research, visit these helpful sites:
- National Institutes of Health
www.nih.gov - International Society for Stem Cell Research
www.isscr.org - Viacord (cord blood banking)
www.viacord.com
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Embryonic stem cells |
Adult (somatic) |
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| Purpose: | “Pluripotent” – able to become all cell types of the body | Able to differentiate (or specialize) within their tissue of origin. |
| Quantity: | Able to be produced in mass quantities (grown in cultures in a laboratory) | More rare; methods for expanding their numbers in cultures have not been perfected. |
| Rejection factor: |
Real potential for “rejection” by the recipient, since it is “foreign” material (like organ transplants) | A patient’s own cells can be reintroduced into his or her body, eliminating the risk of rejection. |
| Most common source: |
Embryos created at fertility clinics | Bone marrow |
| Most promising treatments: |
Parkinson’s and Alzheimer’s diseases, spinal cord injury, stroke, burns, heart disease, diabetes, osteoarthritis, rheumatoid arthritis, muscular dystrophies, liver disease and kidney disease. So far, the research has been limited to non-human subjects. | Primarily blood cancers and other blood disorders, but additional therapies are on the horizon. |
| Research challenges: |
The source of stem cells has presented ethical concerns and controversy. | Their type and isolation present difficulties. They are rare within a given tissue type. |
| Availablilty of treatments: | Cures and treatments (in humans) are still many years away. | A variety of treatments are available and widely used. (See sidebar, “Stem cell Therapy: treatments available now”). |
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