Revised April 26, 2002
What’s the fuss about Stem Cells, Embryonic Stem Cells, Embryonic Cells?
First, let’s cover some basics.
What is a cell?
A cell is the smallest structure unit of an organism that is capable of independent functioning, consisting of one or more nucluei, cytoplasm (the protoplasm outside the cell nucleus), and various organelles (differentiated structure within a cell), all surrounded by a semipermeable membrane. Clear?
Okay then, what is a stem cell?
A stem cell is one that can be formed into virtually any human cell found in the body.
Where do we find these stem cells and how are the created you might ask?
They began with the beginning of life, when the egg from a female of the species - is fertilized by a sperm from the male of the species (the beginning of human life). This is the traditional method of developing the first cell.
When joined the two “gametes” (a reproductive cell, especially a male sperm or egg capable of participating in fertilization) create that single-cell that eventually develops into a baby.
This fertilized egg as you would expect is capable of developing into any of the 210 different types of cells found in the body. This egg is “totipotent” its potential is total. Once this cell has divided into two cells, they are both found to be “totipotent” capable of or the potential of becoming a fully developed baby. This is how and when identical twins begin their journey to becoming babies.
The process continues of cells multiplying or dividing and at some point in time they begin to “differentiate,” or become specialized into one of the 210 different types of cells found in the body.
An outer, hollow sphere of cells encompasses a cluster of cells inside, known as the "inner-cell mass." Together, the cells are known as a "blastocyst." The blastocyst's outer layer of cells will go on to become the placenta and other tissues necessary in nurturing the growth of a human baby. The cells comprising the inner-cell mass can form virtually every type of cell found in the human body, but they are unable to fully develop into a baby without the outer layer. They are know as “pluripotent” cells. If pluripotent cells alone were implanted into a woman's uterus, they would not form into a baby. Because of this, the inner-cell mass cells are not totipotent but rather are called "pluripotent."
The pluripotent stem cells undergo further specialization into stem cells that are committed to give rise to cells that have a particular function. While the inner-cell mass cells of a blastocyst go on to become various organs, nerves and tissues, some of the “multipotent” cells always remain as they are to create replacement cells for their specific functions. Examples of this include blood stem cells that give rise to red blood cells, white blood cells and platelets; and skin stem cells that give rise to the various types of skin cells. These more specialized stem cells are called “multipotent”.
While stem cells are extraordinarily important in early human development, multipotent stem cells are found in children and adults. For example, consider one of the best understood stem cells, the blood stem cell. Blood stem cells reside in the bone marrow of every child and adult, and in fact, they can be found in very small numbers circulating in the blood stream.
While multipotent cells have been found in various areas of adults, they have not yet been found for all human tissues, but progress is being made, according to the National Institutes of Health. Pluripotent and multipotent cells are both refereed to as "stem cells" and are the subject of controversial research making headlines. As you can now understand, that in order to get at these pluripotent and multipotent cells an embryo (baby) has to die. Thus we have controversy.
Complicating the current debates are very recent research findings indicating that yet another heretofore scientific mantra has been broken: the definitions of these three categories of stem cells (embryonic, fetal and adult). It was thought that only the earliest stem cells were "totipotent". But it has now been demonstrated that not only "pluripotent" cells can be "de-programmed" and returned to earlier states of differentiation, but even the most highly differentiated cells can have their biological fates so reversed - as happened with Dolly.
The process of manipulating stem cells into more specialized cells has many potential medical applications.
The three major goals usually cited for pursuing this research are: the gaining of important scientific knowledge about embryonic development and its application to related fields; curing debilitating diseases, e.g., Parkinson’s, Alzheimer’s, diabetes, strokes, spinal cord injuries, bone diseases, etc.; and screening drugs for pharmaceutical companies, instead of having to rely on animal models.
How are stem cells obtained?
As stated earlier, multipotent stem cells can be found in children and adults. The NIH says multipotent stem cells have not been found for all types of adult tissue, but more discoveries are being made. Others claim adult stem cells are not the best specimens from which to create stem-cell lines because the cells have aged and may have suffered damage.
Such scientists advocate pluripotent stem-cell research. But those cells can only be found in a developing embryo, which is where the cells are created. To obtain the cells, left-over embryos from in-vitro fertilization clinics are used. A blastocyst's outer- and inner-cell layers are separated, thus destroying the embryo.
Most commentators agree that the use of stem cells derived from adult human beings are ethically acceptable (assuming other ethical parameters are met). The major point of disagreement involves the use of stem cells derived from early human embryos and aborted fetuses.
Most of those “pro” human embryonic and fetal stem cell research use utilitarian ethical arguments as justification; it is ethically acceptable – even morally required – to destroy a few human beings in order to possibly benefit millions of patients. Besides, these cells do not cause the same immuno-incompatibility problems after transplantation as do adult stem cells from different patients. Further, these early cells from human embryos and fetuses are MORE “totipotent” and “ pluripotent” than adult stem cells, and therefore they can be “coaxed” to become more different kinds of tissues, and can last longer in culture awaiting use. Besides, fetuses and left over IVF produced human embryos are going to die anyway, so “we might as well get some good use out of them”.
In response, opponents of human embryonic stem cell research identify the major ethical problem as the source of those cells. Living human embryos, who are the most vulnerable of human beings, must be destroyed in the process of taking their stem cells out of their bodies for this research, and it is never ethically acceptable to intentionally kill any innocent human being – no matter how small, even if the “possible benefit” is to the “many”. Nor is it ever permissible to do evil that good may come of it. Given that the goals cited by the proponents are laudable and good, the means to those goals must also be ethically good-and here the “means” used in these experiments are the death and destruction of living innocent human beings. It is to reduce them to mere objects for the use of others, rather that subjects with inherent ethical rights deserving of equal protection.
All of which is reminiscence of US slavery laws, Nazi medicine, the Tuskegee syphilis experiments] [1] and US government-sponsored radiation experiments which operated on a two-tier caste of “humanity”. And if impending death were the criteria for being allowed to kill human beings, then we could kill terminally ill patients, death-row inmates and military service personnel facing combat for their organs and stem cells too –for the “greater good”.
Note that fetal cord blood cells have already proven successful, and the use of adult stem cells from the same ill patient would by-pass the medical crisis of immuno-incompatibility. Even foreign adult stem cells can be treated with drugs to “hide” the guilty antigens. New drugs like telomersae can keep these cells growing in culture indefinitely, and new hormones like growth factor are being successfully used to encourage cell specialization. Most critically, even adult stem cells can be “coaxed” to become less specialized (less differentiated), and can even provide cell types distinct from their own usual fate (as already mentioned). Finally, adult stem cells are already closer to the kinds of cells that patients already need.
So there is really NO NEED TO USE HUMAN EMBRYONIC CELLS AT ALL. This has been acknowledged by major researchers, companies and massive numbers of medical research journal articles recently published in this field.
In addition to these arguments, many objectors to this research base their concerns on fundamental Christian principles. Scripture assures us that every human being is made in the image of God from whom we receive our dignity and rights, and from whom we have been promised constant love, protection and guidance. We may not turn the most innocent and most vulnerable human beings into sacrificial lambs for the sake of others, nor weigh only the ends and not also the means.
News on the latest Adult (Somatic –of the body, especially distinguished from a body part) Stem Cell research achievements or incredible breakthroughs.
Ultimate Stem Cell discovered :The cells were found in the bone marrow of adults by Catherine Verfaillie at the University of Minnesota. Extraordinary claims require extraordinary proof, and though the team has so far published little, a patent application seen by New Scientist shows the team has carried out extensive experiments. These confirm that the cells - dubbed multipotent adult progenitor cells, or MAPCs - have the same potential as ESCs. "It's very dramatic, the kinds of observations [Verfaillie] is reporting," says Irving Weissman of Stanford University. "The findings, if reproducible, are remarkable." At least two other labs claim to have found similar cells in mice, and one biotech company, MorphoGen Pharmaceuticals of San Diego, says it has found them in skin and muscle as well as human bone marrow. But Verfaillie's team appears to be the first to carry out the key experiments needed to back up the claim that these adult stem cells are as versatile as ESC’s. (Embryonic Stem Cells)
- Adult stem cells found in skin; An unexpected source of flexible adult stem cells has been found by Canadian researchers - the skin. The finding raises hopes that skin could one day provide an easily accessible source of stem cells compatible with a patient's own immune system. Stem cells are "immature" cells which researchers hope could be coaxed into specific tissues for transplant or therapies. They have previously been isolated from a variety of adult tissues, including the brain, bone marrow, the retina, skeletal muscle and even fat cells. But extracting these tissues can be difficult. See http://www.newscientist.com (a chronicle of Stem Cell development)
- Canadian researchers discovered that nerves can regenerate in the spine when cells from the intestine are transplanted into a severed spinal cord. – National Post, August 16th, 2001-Tom Arnold
- John Hopkins School of Medicine researchers injected non-embryonic stem cells into the spinal fluid of paralyzed mice and rats, half of which partially or fully recovered. National Post, July 28th, 2001 – Michael Fumento
- Cells from liposuction have been transformed into bone, muscle, cartilage and mature fat cells, according to th Journal of Tissue Engineering.
- Two studies in Nature Medicine reported that non-embryonic stem cells injected into rodents can transform themselves naturally into neurons and insert themselves into the brain, giving hope to people with Parkinson’s disorders. A third study found that injecting a chemical into damaged areas of rats’ brains stimulated stem cells to grow and differentiate into a massive number of normal, fully developed nerves. The cells were able to repair damage and restore mobility to the rodents.
- As reported in Molecular and Cellular Neuroscience, rats with degraded retinas were injected with non-embryonic stem cells that traveled to the site of damage, which then showed signs of making connections with the optic nerve and hence improve or even restore vision.
- Dr. Donald Orlic of the National Genome Research Institute told NBC News in later March that “we are currently finding that these adult stem cells can function as well, perhaps even better than, embryonic stem cells.”
- One of the richest source of cells that are not adult, but more importantly non-embryonic, are umbilical cords and placentas from live births. Each year, more than four million umbilical cords are discarded in Canada.
- Adult Stem Cell Procedure Offers Hope to Patients With Crohn's Disease. While the debate rages adult stem cells extracted from the blood of two patients with Crohn's disease have already been used to counteract the autoimmune disease. Researchers from Northwestern Memorial Hospital in Chicago, where the procedures were performed, say that the early results in both cases are very encouraging.. https://www.acurian.com
- CBS News; November 28, 2001 Adult Stem Cells Completely Cure Sickle Cell Patient - Pittsburgh, PA -- Stem cells are thought of as the Holy Grail of medicine. One young boy agrees with that. He made medical history because he's been cured of his life-threatening disease. The key to his cure did not come from a human embryo, where all the controversy is, but from something that is routinely toss in the garbage - an umbilical cord. Umbilical cords were always considered medical waste.
- NY Times December 13, 2001 - Drugs to Spur New Cells - companies are actively working on drugs that stimulate the brain and other organs to grow new cells and repair themselves.
- Doctors in Germany report the successful use of a patient’s own adult stem cells from bone marrow to regenerate tissue damaged after a heart attack. (Reuters Health, July 23, 2001)
- Japanese Scientists use Neural Stem Cells to Decrease Parkinson’s, Japan Neurological Society on Oct. 24 in Okayama.
- Human Adult Bone Marrow Stem Cells Can Form Kidney Tissue, Researchers in Great Britain have found that human adult bone marrow stem cells can form kidney tissue. The work, published in the Journal of Pathology and regeneration,” The Journal of Pathology 195, 229-235; Sept. 2001 (published online July 25, 2001; DOI: http://dx.doi.org/10.1002/path.976
- Treatment of Multiple Sclerosis using the Patient’s Own Cells - Researchers have developed a combined therapy using a patient’s own stem cells for treatment of severe cases of multiple sclerosis. Treatment decreased tissue damage in the patients, and had the capacity to completely suppress further tissue damage, an effect that appears to be sustained with time. Reference G.L. Mancardi et al., “Autologous hematopoietic stem cell transplantation suppresses Gd-enhanced MRI activity in MS,” Neurology 57, 62-68; July 10, 2001.
- Umbilical Cord Blood Effective At Treating Adult Blood Disorders - A new report shows that umbilical cord blood can provide effective treatment of various blood disorders in adults.
- New Corneas Grown from Patients’ Own Adult Stem Cells Treat Corneal Scarring. Several recent reports show the effectiveness of using a patient’s own adult corneal stem cells to treat corneal scarring. The research groups report growth of new corneal tissue and improvement of sight in most patients. Investigators noted that “The technique is suitable not only for acute ocular injury but also for ‘chronic-phase patients with massive scarring’.”
New Orleans, Louisiana, November 13th, 2006 Adult stem cells may soon be used to treat human diabetes, after a study by U.S. Researchers showed the cells increased insulin in mice with Type 2 diabetes, and may also have aided in kidney repair. The study was pulbished online in the early edition of the Porceedings of the National Academies of Sciences. http://www.pnas.org/cgi/reprint/0608249103v1
Human Liver grown from Cord Blood Stem Cells - Media ignores UK breakthrough http://www.lifesite.net/ldn/2006/nov/06110105.html
Adult Stem Cells used to treat
emergency Heart Attack Patients
http://www.lifesite.net/ldn/2006/nov/06110809.html
Adult Stem Cells used to Cure
Blindness
http://www.lifesite.net/ldn/2005/apr/05042907.html
Success Stories with Adult Stem
Cells comming in almost too fast to track.
http://www.lifesite.net/ldn/2005/jan/05012007.html
A New Blood Bank that is worth your Life Saving.
After a baby is born, there is just a 15-minute window to retrieve the four to six ounces of blood in the umbilical cord. And in that blood are potentially lifesaving stem cells that can be saved for future use.
"This is really where, I think, so much of biomedicine is going to be going in the 21st century," says Dr. Andrew Yeager of the University of Pittsburgh.
March 8th, 2002 from Lifesite News
ADULT STEM CELLS IN BLOOD ABLE TO DIFFERENTIATE INTO ORGAN CELLS
HOUSTON, March 7, 2002 (LSN.ca) - Beyond stem cells in bone marrow, scientists have found that stem cells circulating in the blood can also differentiate into mature cells of various organs. Lead researcher Dr. Martin Körbling from the University of Texas demonstrated the finding with biopsy specimens from the liver, gastrointestinal tract, and skin obtained from 12 patients who had undergone transplantation of blood stem cells from peripheral blood. The biopsies gave evidence that the donor blood cells had differentiated into the organ cells of the recipients' organs.
Dr. Martin noted that the finding reflects a change in the perception of the healing of organs. "For years, the school of thought was that when tissue was injured, the repair came from the tissue itself. But we can prove the existence of a systemic supply of stem cells distributed via the blood that are capable of tissue repair," he said.
Importantly, Dr. Martin noted that the adult blood stem cells can be acquired easily. "But unlike bone-marrow stem cells, circulating stem cells can be easily collected from the blood by a routine blood-banking procedure know as apheresis," he said. "So it is conceivable that adult peripheral blood stem cells could be used for repairing injured tissue or even replacing diseased tissue."
See the abstract from the Journal and coverage in the Sun Times:
http://content.nejm.org/cgi/content/abstract/346/10/738
http://www.suntimes.com/output/health/cst-nws-stem07.html
For More Information;
www.lifesite.net
http://www.stemcellresearch.org/
New additions March 11th,
2002
Adult Stem Cell Research More Successful Than Embryonic by Do No Harm
[Pro-Life Infonet Note: Do No Harm: The Coalition of Americans for Research Ethics is a national coalition of researchers, health care professionals, bio-ethicists, legal professionals, and others dedicated to the promotion of scientific research and health care which does not harm human life.]
A report today in the journal Cell, announced by the Associated Press, purports to use "therapeutic" cloning to partially correct a genetic based immune system defect in mice.
However, this report comes years after "remedied" adult stem cells - not embryonic stem cells - were used to cure human infants of severe combined immunodeficiency syndrome, in the first successful clinical trials in human gene therapy.
In the cloning experiments, performed by researchers at the Whitehead Institute (W.M. Rideout et al., "Correction of a genetic defect by nuclear transplantation and combined cell and gene therapy," Cell Immediate Early Publication, published online March 8, 2002) mice with an immune defect causing some white blood cells to be missing were cloned, and the cloned mouse embryos were destroyed for their stem cells. Since the embryonic stem cells were genetically identical to the mice (supposedly to prevent transplant rejection), they carried the same genetic defect. The researchers used gene therapy to fix the defective gene in the embryonic stem cells.
Several different attempts were then made to correct the immune defect in the mice using these stem cells.
In one experiment, the "repaired" embryonic stem cells were differentiated in culture into blood-forming cells and these were transplanted into the defective mice. The authors note that this showed little to no success (though the data are not shown in the paper).
Next they tried reducing the number of those cells in the recipient mice that were blocking successful transplant. Again, this approach was essentially negative (again, the data are not shown in the paper).
Finally, the researchers transplanted the "repaired" blood-forming cells into a different mutant mouse that had the same genetic defect, but also lacked the cells that had been destroying the transplanted cells. This situation resulted in a modest restoration of the missing blood cells, but at less than one-tenth the amounts in normal mice.
However, the researchers were able to restore normal levels of the missing blood cells by first using the "repaired" embryonic stem cells to grow born mice, then using the bone marrow stem cells or blood stem cells (similar to umbilical cord blood) of those born mice for the transplant. In other words, the researchers were most successful when they resorted to using adult stem cells.
The published scientific paper actually shows that the "repaired" embryonic stem cells from cloned embryos were unsuccessful in treating the gene defect in the mice that provided the donor cells for cloning. The authors note: "Our results raise the provocative possibility that even genetically matched cells derived by therapeutic cloning may still face barriers to effective transplantation for some disorders."
This study also bears out the enormous global risk to women's health entailed in the speculative idea of "therapeutic cloning" to treat diseases in humans. Only 1 embryonic stem cell line was successfully cultured, starting with 202 cloning attempts. Even if the experiment had been successful, the number of human eggs needed for such treatments would translate to 303 million human eggs needed to treat the 1.5 million Parkinson's patients in the U.S., and over 3.2 billion human eggs needed to treat the 16 million diabetes patients in the U.S.
Far from being a step forward, this report shows that cloning is years behind the far more successful advances using adult stem cells, including their use to reverse immune deficiencies in humans.
As reported in April 2000 in the journal Science, French scientists restored the immune systems of 3 infants with severe combined immunodeficiency (the "bubble boy syndrome") using gene therapy with the patients' own bone marrow stem cells. ...Since the procedure used the patients' own cells, there was no problem of transplant rejection. ... and the children were living at home and developing normally with no further treatment (M.Cavazzana-Calvo, et al., "Gene Therapy of Human Severe Combined Immunodeficiency (SCID)-X1 Disease," Science 288, 669-672, April 28, 2000).
Far from showing the supposedly superior benefits of stem cells from cloned embryos, the new study shows that this approach continues to lag behind adult stem cell advances - even in mice, where embryonic stem cell research has been pursued for over twenty years. Adult stem cells are successfully treating real human children with serious diseases.
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Texas university researchers have found that human blood stem cells
can be used to grow gut- and liver-tissue, and skin. Blood stem cells
closely resemble those from bone marrow. [New England Journal of
Medicine via AP on New Jersey online, 7 March] 2002
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April 2002
Researchers in the US claim to have treated sufferers of multiple sclerosis (MS) by using the patients' own stem cells. Doctors at the University of Washington Medical Center in Seattle succeeded in stabilising a number of MS patients by removing stem cells from their blood, killing the cells that were working against the immune system,
and then transplanting the healthy cells back into the patients' bodies. The researchers managed to isolate adult stem cells from the patients' blood by generating anti-bodies to the stem cells which were attached to tiny magnetic beads and then mixed with the blood. A magnetic device was then used to draw out the stem cells. [BBC News online, 16 April] Adult stem cell technology provides a promising and ethical alternative to the use of stem cells from embryos and so-called therapeutic cloning.
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Source: Washington Post; April 9, 2002
Adult Stem Cells Work Well in Parkinson's Disease Case
Chicago, IL -- The hand tremors and other symptoms of Parkinson's disease that had started to interfere with a California man's life have largely disappeared since doctors retrieved stem cells from his brain, grew them
into neurons and then transplanted those cells back into his brain, doctors reported yesterday.
The brain cell transplant was the first in humans involving "adult neural stem cells," a recently discovered type of cell that can morph into every kind of brain cell.
If studies confirm the procedure's usefulness in other patients, the approach could evolve into a biological therapy for the disease in which patients would essentially grow their own cures from a few starter cells taken from their own brains.
"It's very exciting and promising as research," said Alex Valadka, a neurosurgeon at Baylor College of Medicine in Houston who heard the results presented yesterday in Chicago at an American Association of Neurological Surgeons meeting. "However, it's always a good idea to temper your enthusiasm with a little bit of caution. This is, after all, reported in only one patient."
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Expert Condemns Media Reports on Supposed
Failure of Adult Stem Cells
A recent scientific study was "distorted" by the media according to
one author of the study. Dr. Naohiro Terada was dismayed that most of the media
left out the most important detail-the adult stem cells which failed had been
mixed with embryonic stem cells.
The experiment included brain and bone marrow adult stem cells from mice which
were mixed with the embryonic stem cells from mice. The adult stem cells had
fused with the embryonic stem cells instead of reprogramming to become the tissues
they were intended to become.
The incident underscores how many in the news media are eager to jump on to
any story that would seem to undercut the most scientifically sound treatment
and research options that exist and instead promote the politically correct
line.
--To read the CNS News article, follow this link: http://www.cnsnews.com/ViewForeignBureaus.asp?Page=/ForeignBureaus/archive/200203/FOR20020325g.html
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April 2002
Canadian researchers claim to have discovered how to take adult stem cells from the blood and mass-produce them in a laboratory. A team working for the British Columbia Cancer Agency inserted a copy of a
gene called HOXB4 into adult stem cells with the result that the cells multiplied at an unprecedented rate. It is suggested that the discovery could be of major importance because adult stem cells are difficult to obtain from the body and have proven almost impossible to multiply outside of the body until now. [National Post online, 2
April] Adult stem cell technology provides an ethical alternative to the destructive extraction of stem cells from embryos and so-called therapeutic cloning.
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Comment: This article is excellent fodder for those who aren’t convince by the past, natural law or absolute moral convictions. (hhw)
The False Promise of "Therapeutic"
Cloning
Or "Where Are We Going to Get the Eggs?"
by Wesley J. Smith
The Senate will shortly take up one of the most pressing moral, ethical, and
scientific issues of our time: the Brownback proposal to outlaw human cloning.
Two alternative proposals would ban only "reproductive cloning," which
would mean explicitly legalizing human cloning but not the implantation of a
clone embryo into a womb.
However, there is increasing evidence that
therapies based on cloned embryo cells would be so difficult and expensive to
develop and utterly impractical to bring to the bedside. Not only is
human cloning immoral but it may have negative utility-in other words,
attempting to develop human cloning technologies for therapeutic use may drain
resources and personnel from more useful and practical therapies.
Those cloning advocates who want cloning research argue that they must be allowed
to legally clone human embryos in order to overcome the problem of tissue rejection
in stem cell treatments. There are two absolutely essential ingredients to successful
nuclear cell transfer cloning. One is a somatic cell (adult) from the clone
donor. No problem there. The other is the egg. And here is where therapeutic cloning hits a brick
wall: We can only create as many patient clones for therapeutic use as there
are eggs available. Where are we going to get the eggs we would need to treat
the millions of patients who would supposedly benefit from clone embryonic stem
cell therapy?
The simple answer is: We aren't going to get them. Assuming that therapeutic
cloning researchers could overcome the genetic defects problem, and assuming
that they could also control the growth of the new cells so as to prevent tumors,
and even assuming perfect clinical conditions, there is no way around the fact
that at least one human egg would be required for each patient. Consider the
number of patients in this country alone with medical conditions for which embryonic
stem cell therapies are being promoted as promising-people with Parkinson's
disease, stroke, Lou Gehrig's disease, multiple sclerosis, spinal cord injuries,
Huntington's disease, and more. According to a National Academy of Sciences
estimate, there are more than 100 million such patients in the United States
alone, meaning that even in a perfect cloning world, we would need at least
100 million human eggs to treat them.
And that isn't the half of it. As daunting as that number is, for the foreseeable
future it will take many eggs to successfully create just one clone embryo.
This means that the actual number of eggs that would be necessary for clinical
application of therapeutic cell cloning is in the hundreds of millions-an utterly
staggering number.
David Prentice, an expert in stem cell research at Indiana State University
and fellow of the Wilberforce Forum, has done the math for just one patient
group: diabetics. There are some 16 million diabetics in the United States.
Prentice assumed that twenty percent of cloning attempts would succeed in reaching
the blastocyst stage of development. This number is based on published reports
on successful production of blastocysts from animal cloning. The number is more
than fair since cloning a genetically sound human embryo would be more difficult
than cloning an embryonic mouse, sheep, or cat.
He next assumed that stem cells would be successfully
derived from ten percent of these clone embryos. This figure is also fair. It
took thirty-six embryos for James Thomson of the University of Wisconsin to
create five human embryonic stem cell lines, a 13.8 percent success rate.
The Jones Institute used 110 embryos to get only three stem cell lines, a 2.7
percent success rate. And these embryos were created through fertilization,
which does not pose the genetic defect problem found in clone embryos.
Using these figures, Prentice computed that it would take 800 million eggs just
to treat the 16 million American diabetics with a therapy involving cloned embryonic
stem cells.
Obtaining human eggs for this purpose would involve stimulating the ovaries
to hyper-ovulate, which generally produces seven to ten eggs. Assuming a liberal
ten eggs harvested from each procedure, 80 million women of childbearing age
would be needed as donors.
Now, consider the difficulties involved
with hyper-ovulation. After the ovaries are stimulated to release multiple eggs,
the eggs are surgically extracted. A partial list of potential
side effects from the procedure include rupture of the ovaries, severe pelvic
pain, accumulation of fluid in the abdomen as well as around the heart and lungs,
bleeding into the abdominal cavity, acute respiratory distress, and pulmonary
embolism. That being so, how many women are going to be willing to provide
eggs for use in cloning? Will we have to create markets in human eggs?
The "egg dearth" is a mathematical certainty. This means that if clone
embryonic stem cell therapy were ever successfully developed, it would have
to be either severely rationed or available only to the very rich. But therapeutic
cloning is being held out as a panacea for the many, not as a rare procedure
available to the very few. That's a false hope. The real "promise"
of therapeutic cloning is this: Millions of Third World women being paid to
submit to operations for the benefit of rich Americans.
When it comes to the issue of stem cell therapies, the evidence is becoming
overwhelming that our limited resources are most wisely spent pursuing research
into adult stem cells as our best and quickest hope for developing efficacious
new medical treatments. Adult cells don't appear
to lead to tumors. And since the patient's own cells are used, tissue rejection
is not an issue. Moreover, adult stem cells are already used to treat human
ailments such as heart disease and auto immune deficiencies-which even
the most optimistic proponents of therapeutic cloning admit are many years away
using embryonic stem cells. In this regard, it is worth noting that the American
Red Cross recently refused a National Institutes of Health grant to work on
embryonic stem cells in order to focus more intensely on research involving
stem cells found in umbilical cord blood. Why concentrate on umbilical cord
blood and exclude work on embryos? The Red Cross representative could not have
been clearer: "We really need to focus our resources, our attention, on
those areas where we could most likely provide, in the shortest period of time,
some therapies for our patients."
To pour money into human cloning embryonic stem cell research is to risk drilling
one dry hole after another. The moral policy thus also turns out to be the pragmatic
one. The United States Senate should vote to ban all human cloning now.
This article was adapted from the original article in The Weekly Standard
http://www.weeklystandard.com/Content/Public/Articles/000/000/000/972qujyx.asp
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Scientists transform adults' stem cells
Discovery could increase pressure to stop using embryos
Brad Evenson
National Post
Friday, June 21, 2002
U.S. scientists report they have transformed stem cells found in adult bone marrow into virtually all types of cell in the body, raising hopes they could be used to create a bottomless pool of cells for treating diseases ranging from AIDS to Alzheimer's.
If the findings are confirmed by other labs, this will increase pressure on scientists to stop experimenting with stem cells derived from human embryos.
"If this is absolutely true, I think it will change everything," says Dr. Abdullah Daar of the University of Toronto Joint Centre for Bioethics. "Should adult stem cells ever prove to be as good as [embryonic] cells, then why would anybody want to bother with embryonic stem cells?"
Underscoring the field's potential, a second study yesterday found stem cells replaced damaged brain cells and reduced symptoms of Parkinson's disease in mice. Both studies were published online by the journal Nature.
Sometimes called the "ultimate spare parts," stem cells have the unique ability to copy themselves or grow into any of the body's 220 specialized cells, from neurons to liver cells.
Embryonic stem cells are controversial because embryos must be destroyed to recover them.
But adult stem cells could, in theory, be withdrawn from a patient and induced to blossom into whatever cell types the patient needs, such as immune cells in the case of AIDS patients.
Last year, scientists at the University of Minnesota Stem Cell Institute reported their lab had found stem cells in the bone marrow of adult humans that grew into a variety of cell types -- but only in a test tube.
Yesterday, the same team reported the next step. Working in mice and rats, it reported adult stem cells -- multipotent adult progenitor cells, known as MAPCs -- could morph into hundreds of specialized cells inside the body. In one experiment, researchers injected single MAPCs into a mouse embryo. After birth, descendant cells of the MAPCs showed up in "pretty much every organ we looked at," said lead researcher Catherine Verfaillie.
The study is drawing praise from top experts.
Alan Bernstein, president of the Canadian Institutes of Health Research and a world authority on stem cells, called it a "beautiful paper." Indeed, some of the techniques used at the Verfaillie lab draw on Dr. Bernstein's own research from the 1980s. He says using adult cells makes good medical sense.
"Aside from the ethical issues, if one could take one's own adult ... stem cells from bone marrow and use them to cure Parkinson's disease, you wouldn't have to worry about [immune] rejection problems," he says. "So this would be just a huge advance."
This study adds to the sea change in scientific thinking that adult cells are not as "plastic" as embryonic cells. "In general, there has been a dogma that's grown up over the years that cells that are neurons are not going to switch and become blood cells tomorrow, or muscle," says Dr. Bernstein.
"It looks like the minimum one can say is the old view ... is going to have to be modified."
However, Dr. Bernstein says much more research is required.
One key question that has dogged adult stem cell research is whether such cells actually function when they become specialized cells.
For example, Montreal Neurological Institute researcher Freda Miller has found adult stem cells in the skin called SKPs. They can morph into nerve, muscle and heart cells, but no one knows if they actually work yet.
"It's not enough to look like a liver cell, you have to behave like one, too," says University of Toronto stem cell researcher Peter Zandstra.
The Minnesota study offers a hint the new cells are working. In some mice and rats, up to 45% of the heart's cells descended from MAPCs and the animals remained healthy, so the heart cells were evidently working fine, says Dr. Verfaillie.
A second study by scientists at the U.S. National Institute of Neurological Disorders and Stroke adds further hope. Among the first studies to show stem cells can develop into neurons that function in the brain, it found that stem cells could morph into neurons that secrete dopamine, the brain chemical that dries up in Parkinson's patients. Parkinsonian rats that received stem cell transplants showed improvement in their symptoms.
Taken together, the Nature studies will put political pressure on scientists to justify why they choose to conduct research on embryonic cells instead of adult cells.
However, many questions about adult stem cells remain, says Ron Worton, scientific director of the Canadian Stem Cell Network, based at the University of Ottawa.
In the meantime, embryonic stem cell research should move ahead, he says, since understanding how these primitive cells grow will allow doctors to understand what controls their behaviour.
"There is no question that before we put these things into humans, we'll have to know how they're regulated," says Dr. Worton.
He paints a nightmare scenario of a stem cell being transplanted into a patient's brain, "but it turns into bone."
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[1] [1] ): "Beginning in the 1930s, 399 men signed up with the U.S. Public Health Service for free medical care. The service was conducting a study on the effects of syphilis on the human body. The men were never told they had syphilis. They were told they had "bad blood" and were denied access to treatment, even for years after penicillin came into use in 1947. By the time the study was exposed in 1972, 28 men had died of syphilis, 100 others were dead of related complications, at least 40 wives had been infected and 19 children had contracted the disease at birth." (Quoted from CNN Interactive's Tuskegee Study Website)