By Susan Margrave
Stem-cell research holds many promising possibilities but is in its early stages. The arguments by opposing religious, ethical and philosophical camps are as plentiful as the possibilities pondered by scientists.
An audience of about 50 gathered in McBrien Hall on Oct. 14 to hear an explanation of stem cells, varieties, functions and healing possibilities by Dr. Mike Matthews, professor of biology. Dr. Kevin Durand, assistant professor of philosophy, presented a paper by the late Dr. William Gentry, a Henderson philosophy professor who suffered from Parkinson's disease and cancer.
The presentation was part of "Get Reddie to Vote," a voter education effort by Ellis College of Arts and Sciences.
Matthews began by defining for the audience what scientists mean when they refer to a stem cell. The various types of stem cells share a group of characteristics. They are unspecialized cells, which means they have the potential to become any cell in the body. They're self-renewing, which means they can multiply without changing. And they can differentiate, which means they can be stimulated to become a particular kind of cell, Matthews said.
There are four types of stem cells, he continued: embryonic, fetal, cord and adult.
Embryonic and fetal stem cells are the groups figuring most prominently in media reports these days, he said, and generating the most controversy. It is important to understand the various research roles and properties of each of the groups.
Stem cells may be pluripotent, which means that they can form all the cells of an adult human; totipotent, which means they can form all the cells of a human being from conception; or multipotent, which means they can be stimulated to form a specific type of cell.
Matthews said the scientific community first began talking about stem cells in the 1960s, when researchers were able to isolate mice stem cells in a lab. Work progressed until researchers came up with the techniques for in-vitro fertilization in 1968. Louise Brown, the first so-called "test-tube baby" was born 10 years later in England, marking another important date on the stem-cell timeline. In 1981, the first embryonic stem cells were isolated in mice. In 1996, the stem cells of rhesus monkeys and marmosets were isolated. And in a critical year in research, 1998 saw the first human embryonic stem cells grown and isolated at the University of Wisconsin, one of three leading research centers.
Researchers for a time held out hope that fetal germinal cells could be used to develop treatment or cures for diseases such as Parkinson's and diabetes and to regenerate spinal cord tissues, Matthews said. Those stem cells came from aborted fetuses and provoked the highest level of controversy among the religious, ethical and moral circles opposing stem cell research. Scientists now have found that those groups of stem cells do not have the qualities and characteristics needed to develop healing methods, and those types of cells are not getting much emphasis, he said.
When an egg and a sperm unite, they form a zygote, which is totipotent and can form any cell in the body, Matthews said. When the zygote is allowed to grow for five days, it becomes a blastocyst, which is the tissue that fertility specialists implant in the uterus of patients.
It is an inner-cell mass of 30 cells that is harvested as embryonic stem cells, which are pluripotent and can become any adult cell, he said. Researchers are more interested in studying these groups of stem cells, Matthews said, with an eye toward treating or curing diabetes, Parkinson's or spinal cord injuries. All of these cells are derived from leftover embryos in fertility clinics, he said, which would be disposed of eventually. "It's a waste," he said. "Why waste a human life by discarding it? Why not use it for research?"
Cord stem cells are adult stem cells found in the blood of a baby's umbilical cord, he said. Adult stem cells are very rare, he said, with only about 1 in every 15,000 cells in tissue being an adult stem cell.
Researchers are hopeful that their studies will lead them to discoveries like the hemopoetic stem cell, which made possible bone-marrow transplants, he said.
"We're not even close to figuring out stem cells," he added.
The issue became more clouded when politics began to mix in, he said. From August 1, 2001, forward, he said, no federal funds may be used for stem cell research except on the stem cell lines that existed before that date. Of the 50 lines that existed, only about 15 were available for research, and some of those lines were believed to be corrupted with viruses or other problems. Private foundations are providing millions for the research, however.
"Blastocysts are excess embryos not needed for transplantation," he said. "Why waste it?"
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The philosophical opposition to the use of embryonic stem cell research was uniquely covered by Durand, who read from "The Morality of Using 'Surplus' Human Embryos in Stem-Cell Research," a paper by the late Dr. William C. Gentry, emeritus professor of philosophy at Henderson.
In the paper, Gentry noted that opponents of the research insist that embryos are human beings but noted there is no way that empirical science can determine "the 'humanity' of a blastocyst of approximately two-hundred cells. The humanity of an organism is not a description of its biological composition; it must mean more than or something different from its simply having human DNA."
Gentry went on to note that the leading philosophical opponents of embryonic stem-cell research constructed their ethical views "on the theory that that which is the most real about every existing entity is a natural or God-given essence. The essence is something's 'what-ness,' its definition, or its classification within the order of entities to which it belongs. (The essence of anything is distinguishable in thought from its existence, its 'that-ness.')"
He traced the roots of this theory back to Aristotle. According to Aristotle, he said, the essence of every real entity is an intelligible "form," which is somehow "embodied" in the individual thing itself. The individual features that make an individual unique are less real and unchanging than the essence of shared humanity, according to Aristotle. Opponents of stem-cell research, then, maintain that the potential for embryonic stem cells to become thinking adult human beings outweighs the fact that they likely will never be transplanted into a uterus and allowed to grow.
Gentry, who was suffering from Parkinson's disease and was undergoing treatment for non-Hodgkin's lymphoma at the time he was writing the paper, summed up his examination with these words:
"To question, as we must, the logic of the claim that all human embryos have a moral right not to be destroyed is not to imply that human embryos have no value. All human embryos are valuable! The intrinsic value of the embryo which is successfully implanted in the mother's womb is of such a nature that we should exercise the utmost care to protect its viability. However, it is not necessary to try - and to fail - to justify a claim to moral and legal right to life for this embryo. Its intrinsic value as a potential human person is alone sufficient reason, without the imposition of legal prescriptions, to warrant the protection of its life. Surplus embryos from fertility clinics which will never develop into human persons are also extremely valuable. Their value is extrinsic rather than intrinsic, and the greater moral good will be served by employing these embryos as resources for federally funded research directed toward discovering effective means for relieving millions of people of suffering and disability."
(A copy of Gentry's paper is available in the office of Dean Maralyn Sommer of the Ellis College in McBrien Hall. The paper also will be available online shortly through links with the philosophy department.)
Dr. Mike Matthews Dr. Kevin Durand