Human stem cells

What about using adult stem cells?

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What are stem cells?

As stated elsewhere on this web site:

"The human body contains 220 different types of cells. Stem cells are a type of primitive cell. Scientists have found ways of developing stem cells derived from embryos into most types of human cells, such as blood, brain, heart tissue, nerve cells, bones, etc. Researchers are confident that they will lead to treatments to many diseases....The 'Coalition for the Advancement of Medical Research' estimates stem cell research shows promise to develop cures and/or new treatments for 100 million Americans who currently suffer from a wide variety of diseases and disorders."

The harvesting of stem cells from embryos has become a very hot political, religious, and ethical topic. As in the debate over abortion access, the pro-life and pro-choice movements take opposite positions about the ethics of embryo stem cells research. There is general agreement that an ovum, spermatozoon, pre-embryo, embryo, fetus and newborn contain human DNA and are clearly alive. Thus, they are all forms of human life. The key difference between the pro-life and pro-choice movements is the point when they believe human life (as in an ovum or spermatozoon) becomes a human person and is thus worthy of legal protection:

The pro-life movement generally believes that this happens at, or shortly after, conception. Thus, they consider the removal of stem cells from an embryo -- a procedure which kills the stem cells -- to be a form of murder of a human being. They argue that no potential health benefits to even hundreds of millions of people can justify the murder of other humans.

The pro-choice movement generally believes that personhood is attained much later in pregnancy, perhaps when the fetal brain develops consciousness during the third trimester. Thus, extracting stem cells from an five or ten-day old pre-embryo is not murder. Killing a pre-embryo, which is only a potential human being, is justified if it has the potential to cure diseases and extend the lives of people.

Stem cells can also be obtained from sources other than embryos. They are called "adult stem cells." Their use is relatively free of ethical conflicts. Both the pro-life and pro-choice movements favor further research on stem cells from these sources.

Researchers began using adult stem cells from bone marrow back in 1960. It was only in 1998 that other researchers were able to isolate and cultivate embryo stem cells. ₁₂ Adult stem cell research thus has an almost four decade head start compared to embryo-derived stem cells. As of 2004-Fall, promising trials were underway using adult stem cells. By mid-2007, there are many experimental treatments available using adult stem cells. Meanwhile stem cells from embryos are still being experimented upon in the laboratory.

In late 2007, a method was made public of reprogramming adult stem cells to have many of the properties of embryonic stem cells. This has the potential to combine the potential range of treatments and cures of embryonic stem cells with the lack of ethical concerns over the use of adult stem cells.

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Where do adult stem cells come from?

Some sources:

	One supply is from human fetal tissue. The first human stem cells were extracted from "primordial gonadal tissue which was taken from a non-living fetus." ₁ Fetal tissue research can be legally funded from government sources.
	Advanced Cell Technology claims that they have been able to extract human stem cells by fusing human fetal tissue with parts of a cow's egg. ₂
	Stem cells can be extracted from brains of cadavers, from bone marrow of living patients, from umbilical cords, and from human placentas. Unfortunately, such extraction is more difficult, and gives smaller yields. Also, it has been generally believed that the cells produced have limited potential. They can only produce a few of the 220 types of cells in the human body.
	Canadian researchers at the Montreal Neurological Institute have studied the second layer of skin, the dermis. It contains "skin-derived precursors" or SKP's. These stem cells have been coaxed into producing four different cell types. They also grow well in the laboratory. Of particular importance is that the cells contain the same DNA as the subject; thus there is no danger of rejection. They can be transplanted without the necessity of the patient taking immuno-suppressant drugs.

Promotion of adult stem cell research by the pro-life community:

The pro-life community promotes the use of stem cells from these sources, because they do not require the killing of an embryo. Most spokespersons promote adult stem cells as superior to those extracted from embryos. They rarely, if ever, mention that:

	Adult stem sells may lack the potential to generate all the tissue types needed.
	Adult stem cell research is more advanced, at least in part, because of its four decade head start over embryo stem cell studies.

Some statements supporting adult stem cell research:

James Dobson: Undated:

"Focus on the Family encourages scientists to continue to explore stem cells found in adult tissues, bone marrow and umbilical cord blood. Initial research using these sources are considered to be very promising, even more promising in some instances than embryonic stem cell sources." ₂

Jakki Jeffs of Alliance for Life Ontario: 2001-JUL:

"Adult stem cell research provides a legitimate, moral and ethical alternative area of research. Adult stem cell research has already been used successfully for therapeutic benefit in human beings..." ₃

Canadian Physicians for Life: 2001-APR:

"The scientific literature overwhelmingly demonstrates that adult stem cells are already fulfilling the goals only hoped for with embryonic stem cells, making the destruction of human embryos unjustifiable." ₄

Bioethicist Dr. Nigel Cameron: 2002-SEP:

"We know that adult stem cells, which have no ethical problem, can do the job, as well." ₅

Massachusetts Family Institute: 2004-OCT:

"Adult stem cells are regenerative cells of the human body that can be coaxed to become a whole host of tissues, including heart tissue and neural matter. With these adult stem cells, physicians have successfully treated autoimmune diseases such as lupus, multiple sclerosis, Crohn�s disease, and rheumatoid arthritis. They have also restored proper cardiac function to heart attack victims, and improved movement in spinal cord injury patients. Embryonic stem cells have yet to yield one single success in the treatment of any ailment." ₆

Original assumption: adult stem cells have limited potential:

Research prior to 2002 caused researchers to conclude that adult stem cells are very limited in potential. They are difficult to obtain, grow slower, and are less robust when compared to cells extracted from embryos.

National Institutes of Health stated that: "...there is evidence that adult stem cells may have more limited potential than hPSCs [human pluripotent stem cells]. First, stem cells for all cell and tissue types have not yet been found in the adult human. Significantly, cardiac stem cells or pancreatic islet stem cells have not been identified in adult humans. Second, stem cells in adults are often present in only minute quantities, are difficult to isolate and purify, and their numbers may decrease with age." ₇

Newsroom.com reported that: Cells from adults "are available in far smaller quantities and could treat only a limited range of body parts, researchers contend. No adult stem cell has yet been found that could treat heart disease, for example, so scientists would rather cultivate embryos to harvest their stem cells." ₈

The National Bioethics Advisory Commission stated: "In our judgment, the derivation of stem cells from embryos remaining following infertility treatments is justifiable only if no less morally problematic alternatives are available for advancing the research � The claim that there are alternatives to using stem cells derived from embryos is not, at the present time, supported scientifically. We recognize, however, that this is a matter that must be revisited continually as the demonstration of science advances."

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Adult stem cells may offer greater potential than originally believed:

In early 2002, New Scientist magazine reported that Catherine Verfaillie's team at the University of Minnesota had found stem cells in the bone marrow of adults that may be capable of becoming almost any of the 220 tissue types in the human body. These "multipotent adult progenitor cells" or (MAPCs) might match the flexibility and potential of stem cells derived from embryos. Verfaillie's team, was able to isolated MAPCs from about 70 of the approximately 100 people who donated samples of their bone marrow. ₁₀

Meanwhile, Osiris Therapeutics has produced "mesenchymal stem cells" (MSCs) which has been shown capable of producing a few tissue types, such as bone, cartilage, fat and muscle. They have one unusual property: when transplanted, they appear to trigger little or no immune reaction. ₁₁

The jury is still out on the relative potential of adult and embryo stem cells:

	Steve Brozak, a New York biotechnology investment banker who is running for Congress in New Jersey as a Democrat said: "This is voodoo science. This is only a political sidestep. Adult-stem-cell research holds no real promise that I can see. It's not usable."
	Jay P. Lefkowitz, a former adviser to Bush on stem-cell policy said: "Adult stem cells are really where the real progress is being made."

A new technique was announced in 2007-NOV that may be able to reprogram adult stem cells to behave as if they had many of the properties of embryonic stem cells. This may allow adult stem cells to have the same potential as embryonic stem cells without significant ethical concerns.

References used:

Anon, "Human Embryo research/fetal experimentation," Focus on the Family, Policy statement dated 1997-DEC-15. See: http://www.family.org/
"Focus on the Family statement on human embryo stem cell research," at: http://www.family.org/d
Jakki Jeffs, "An alternative exists to embryonic stem cell research," Toronto Star, 2001-JUL-6
"Stem Cell Research," Canadian Physicians for Life, at: http://www.physiciansforlife.ca/
Steve Jordahl, "Calif. Governor Signs Stem Cell Bill," at: http://www.family.org/
"Stem Cell Research," Massachusetts Family Institute, E-Alert, 2004-OCT-14.
National Institutes of Health guidelines for research using human pluriopent stem cells," at: http://www.nih.gov/
"Britain debates cloning embryos to treat disease," Maranatha Christian Journal, at: http://www.mcjonline.com/
"Ethical Issues in Human Stem Cell Research," , National Bioethics Advisory Commission September, 1999. Quoted in: The Coalition of Americans for Research Ethics at: http://www.stemcellresearch.org/
Sylvia Pagan Westphal, "Is this the cell that could revolutionise medicine?," 2002-JAN-26, New Scientist (http://www.newscientist.com) Online at: http://www.eurekalert.org/
Sylvia Pagan Westphal, "Greater potential of adult stem cells revealed," New Scientist, 2004-MAY-17, at: http://www.newscientist.com/
Michael S. Rosenwald, "Researchers Turn To Adult Stem Cells. Biotech Firms See Potential for Medical Use," Washington Post, 2004-AUG-220, Page E01. Online at: http://www.washingtonpost.com/