The first article is background information on therapeutic
cloning
First steps in therapeutic cloning taken as stem cells collected from cloned
mouse embryos produce neurons, cells.(Brief Article)
Transplant News - May 12, 2001
Word count: 783.
citation details
Two teams of scientists have extracted stem cells from cloned mouse embryos and
used them to form both basic and specialized cells, including a type of neuron
that is deficient in Parkinson's disease and insulin-producing cells that are
damaged in diabetes.
If these first successful attempts at therapeutic cloning work in humans, it
might one day be possible to treat degenerative diseases such as Parkinson's,
Alzheimer's, and multiple sclerosis, as well as illnesses like diabetes, using
stem cells harvested from embryos cloned from the patient's own cells. The
replacement tissue would be genetically identical to the person's own cells,
virtually eliminating the risk of immune system rejection.
In a study published in the April 27th issue of Science, researchers from
Rockefeller University and Memorial Sloan-Kettering Cancer Center in New York
described using adult mouse cells to create cloned embryos. One week later,
after the embryos had reached the blastocyst stage and contained approximately
100 cells each, the scientists removed the stem cells and expanded them in
culture. The cells then were coaxed into forming either ectodermal, mesodermal,
or endodermal cell types-the most basic cells of early development-or
specialized brain cells. This achievement, according to Teruhiko Wakayama, PhD
and coauthors, demonstrated that the stem cells truly were pluripotent and
capable of developing into a variety of cell types from the most primitive to
the most specialized.
In another study appearing in the April 26th online issue of Sciencexpress,
investigators at the National Institute of Neurological Disorders and Stroke in
Bethesda, MD reported the generation of insulin-producing clusters from mouse
embryonic stem cells-again cloned from adult mouse cells. When implanted into
diabetic mice, the cell clusters functioned like normal pancreata, producing
insulin and other hormones required to maintain healthy blood sugar levels.
Furthermore, glucose from food triggered the release of insulin from the cells
through a mechanism similar to the body's natural insulin-release mechanism.
"This is the first example of assembling a functional, multicellular organ from
cells grown in the lab," said Ron McKay, PhD and coauthors.
The possibility of developing new treatments through human therapeutic cloning
led British lawmakers in January to pass a law allowing it (but not human
reproductive cloning), so long as embryos are not permitted to develop beyond 14
days. The Bush administration has delayed the first meeting of a committee
charged with reviewing applications for government funding of embryonic stem
cell research. President Bush has said he is opposed to such investigations, and
a bill was introduced in Congress on April 26th that would ban all human
cloning, including therapeutic cloning. But other officials, including
Department of Health and Human Services Secretary Tommy Thompson, have supported
the work.
The debate pits researchers against religious conservatives, with opponents
contending that creating or harvesting human embryos for stem cells is
tantamount to murder. But many scientists who oppose human reproductive cloning
believe that therapeutic cloning research holds the potential for fantastic
medical advances and should be permitted. Rudolf Jaenisch, PhD, a professor of
biology at the Massachusetts Institute of Technology in Cambridge, is a critic
of reproductive cloning because animal studies suggest the technique can produce
abnormal offspring. But he and other researchers argue that before the cloned
embryo is implanted in a uterus and starts forming specialized tissues, it
essentially is an undefined "ball of cells."
"Is this a small person? Some people would probably believe it is," Jaenisch
said. "I think the majority of scientists do not believe that." Similar
arguments are made for embryonic stem cell research that does not involve
cloning, said Jaenisch. Most of this work, done with private funding, uses extra
embryos originally created for in vitro fertilization.
In an editorial appearing in the same issue of Science, Nobel laureate David
Baltimore, president of the California Institute of Technology in Pasadena,
warned that a moratorium on embryo stem cell research and transplantation could
be "devastating." Although work with adult stem cells is promising, it still is
only a hope, Baltimore wrote, "and it would be foolish to abandon the surer path
for the unproven one." If US researchers do not move ahead on such work, he
warned, advances may come from Britain and other nations where the research is
permitted.
Robert Lanza, vice present for research at Advanced Cell Technology in
Worcester, MA which plans on pursuing therapeutic cloning in humans, said he
believes other nations surely will move ahead with therapeutic cloning even if
the United States does not. "I would say at least one or two groups will report
something within the next year," Lanza said.
Citation Details
Title: First steps in therapeutic cloning taken as stem cells collected from
cloned mouse embryos produce neurons, cells.(Brief Article)
Publication: Transplant News (Newsletter)
Date: May 12, 2001
Publisher: Transplant Communications, Inc.
Volume: 11 Issue: 9 Page: NA
This next article is an editorial against therapeutic cloning by a person in the
right to life movement.
Therapeutic Dreaming: The false promise of experimental cloning.
National Right to Life News - October 1, 2003
Wesley J. Smith
Word count: 1418.
citation details
Polls show that most Americans want to ban all human cloning. President Bush is
eager to sign such a measure into law. The House has twice enacted a strong
legal prohibition with wide, bipartisan votes. But cloning advocates have so far
blocked passage of a ban in the Senate (Brownback/Landrieu) by asserting that
"therapeutic cloning" might someday provide stem cell treatments for horrible
illnesses such as Parkinson's and multiple sclerosis. (I believe the term
"therapeutic cloning," is loaded and misleading. However, I use it here because
the term is currently part of the popular lexicon.)
According to the Biotechnology Industry Organization, the biotech industry's
lobbying arm, here's how therapeutic cloning would work:
Suppose a middle-aged man suffers a serious heart attack while hiking in a
remote part of a National Park. By the time he reaches the hospital, only a
third of his heart is still working, and it is unlikely he will be able to
return to his formerly active life. He provides scientists a small sample of
skin cells. Technicians remove the genetic material from the cells and inject it
into donated human eggs from which the chromosomes have been removed. These
altered eggs [actually, cloned embryos] will yield stem cells that are able to
form heart muscle cells. Since they are a perfect genetic match for the patient,
these cells can be transplanted into his heart without causing his immune system
to reject them. They grow and replace the cells lost during the heart attack,
returning him to health and strength.
This scenario is typical of the hype that has pervaded discussions of
therapeutic cloning over the last few years. But now, cold reality is setting
in. Biotech researchers and cloning advocates are admitting difficulties in
their professional journals, if not yet in the popular press, that make
therapeutic cloning look more like a pipe dream than a realistic hope.
Consider a paper by Peter Mombaerts of Rockefeller University, "Therapeutic
Cloning in the Mouse," just published by the National Academy of Sciences (NAS).
Mombaerts has been investigating therapeutic cloning techniques in mice. It has
been tough going. Of these efforts, he sadly reports, "The efficiency, or
perhaps better, the lack of efficiency thereof, is remarkably consistent." It
takes about 100 tries to obtain one viable cloned mouse embryonic stem cell
line.
Mombaerts notes that creating human cloned embryos using "nuclear transfer is
unlikely to be much more efficient" than it is in mice, especially given that
"the efficiency of nuclear transfer has not increased over the years in any of
the mammalian species cloned." Nuclear transfer, more precisely somatic cell
nuclear transfer (SCNT), is the same procedure used to create Dolly the sheep.
The nucleus from an egg is removed and replaced with the nucleus from a clone
donor's somatic cell, such as a skin cell. The modified egg is stimulated with
an electric current. If the cloning "works," a cloned embryo is created that
then develops just like a naturally created embryo.
Given the significant difficulties researchers have already had, deriving cloned
embryonic stem cell lines is likely to be far less efficient in humans than it
has been in mice (assuming that it can be accomplished at all).
This is big news and let's hope senators are paying attention. If they are, it
should sink the rival to Brownback/Landrieu, Orrin Hatch and Dianne Feinstein's
cynically misnamed Human Cloning Ban and Stem Cell Research Protection Act of
2003, which would not outlaw human cloning at all but would explicitly legalize
it. If it takes 100 or more tries to make a single human cloned embryonic stem
cell line, therapeutic cloning is all but doomed as a viable future medical
treatment.
It's a simple matter of resources. There are more than 100 million Americans,
according to the National Academy of Sciences, who might one day benefit from
therapeutic cloning if all the high hopes for it panned out. Each therapeutic
cloning attempt would require one human egg. If it takes 100 tries per patient
for a cloned embryonic stem cell line to be successfully created, therapeutic
cloning will never become a widely available therapy in medicine's armamentarium
because there will never be enough eggs.
Do the math: 100 million patients at 100 eggs each would mean that
biotechnologists would need access to at least 10 billion eggs just to treat the
Americans the NAS has identified as having degenerative conditions that might
respond positively to stem cell therapy. Even if we decided to strictly ration
therapeutic cloning to, say, the sickest 100,000 patients, you would still need
10 million eggs! Even this strict rationing would require one million women of
childbearing age to submit to egg extraction. These numbers are mind-boggling.
Is there a way out of this egg dearth? Mombaert's article suggested two
potentialities, to which I add a horrific third:
(1) Researchers could use animal eggs. Animal eggs are more readily available
than human eggs, which would reduce the price of therapeutic cloning
considerably. But using animal eggs would mean creating human embryos containing
some non-human dna. I doubt the American people would stand for this violation
of nature's laws. (Mombaerts understates the case when he admits, "The idea of
generating embryos with mixed human/animal properties, even transiently, is
offensive to many people.") From a practical standpoint, the stem cells and
indeed all tissues that would be extracted from such human/animal hybrids would
contain nonhuman mitochondrial DNA. This could easily stimulate an auto-immune
response or risk mitochondrial diseases in patients.
(2) Researchers might be able to learn how to transform embryonic stem cells
taken from fertilized embryos into fully formed human eggs. This has been done
in mice, but it will take many years to determine whether it can also be done
with humans. But even if researchers learn how to morph stem cells into eggs,
that does not mean they would be ready for use in cloning. Researchers would
also have to ensure that they were not genetically defective and learn how to
mature these eggs to the point where they would be usable for cloning. And even
if they were able to learn how to do that, considering the huge number of eggs
that would have to be produced in this way for therapeutic cloning to become
widely available, morphing eggs out of embryonic stem cells hardly seems a
plausible answer to the implacable egg dearth.
(3) Researchers could take the ovaries from female fetuses destroyed in
late-term abortions, and maintain them in the hope of harvesting and maturing
their eggs. I know this is revolting, but, sad to say, Dutch and Israeli
researchers are already experimenting on this very thing with second- and
third-trimester aborted fetuses, toward the goal of obtaining eggs for use in
infertility treatments. Not only does this macabre research open the possibility
that an aborted baby girl could become a mother, but if the procedure were
perfected, it could result in aborted late-term female fetuses becoming a prime
source of eggs for use in human cloning. As if that weren't troubling enough,
the abortions of these female fetuses would have to be done in a way that did
not damage their nascent ovaries, perhaps providing utilitarian impetus for the
odious partial-birth abortion technique.
To pursue therapeutic cloning is to chase a mirage. On the other hand, adult
stem cell research, a practical and moral alternative to therapeutic cloning, is
already in human trials and moving ahead at tremendous speed. It was just
announced, for example, that four out of five seriously ill human heart patients
in a trial in Brazil no longer need heart transplants after being treated by
their own bone marrow stem cells.
With all of the serious problems, both moral and practical, associated with
human cloning, there is no longer any excuse for the current political impasse.
The time has come for our senators to toss the Hatch/Feinstein phony cloning ban
in the round file and pass the Brownback/Landrieu ban without further delay.
Wesley J. Smith, a senior fellow at the Discovery Institute, is writing a book
about the science, morality, and business of human cloning. This article first
appeared in the Weekly Standard in a slightly different form.>EN
This article is for therapeutic cloning and written by a scientist.
Take therapeutic cloning forward
The Scientist - July 22, 2002
Arlene Judith Klotzko
Word count: 1470.
citation details
What will the US Senate actually do about therapeutic cloning-the procedure of
using nuclear transfer to derive embryonic stem cells? The saga continues with
the sudden plot changes, reversals of fortune, mischievous machinations, and the
cliff-hanger ending worthy of a mystery thriller. The latest twist has not
occurred in the Senate itself but in the laboratory. The journal Nature
published two reports on stem cells in rodent models that are no less than
thrilling to those of us who hope for-and wait for-- cures. Ron McKay and his
team at the National Institutes of Health have shown that stem-cell therapy
actually works.1 In a rat model, mouse embryonic stem cells differentiated into
neurons, secreting dopamine, and actually reversed the symptoms of Parkinson
disease.
Research by Catherine Verfaillie and her team at the University of Minnesota
demonstrates that a certain type of adult bone marrow cell, called MAPC, can
differentiate into a wide range of cell types.2 Until now, it was believed that
only embryonic stem cells had such an open biological future. MAPCs are
remarkably malleable; they are also far less morally contentious.
Before this research became known, US Sen. Sam Brownback's (R-Kan.) bill to
criminalize therapeutic cloning seemed virtually dead. His fallback position is
said to be a moratorium rather than an outright ban. Indeed, in a 10-7 split
vote, President George W. Bush's bioethics advisory council has just recommended
a four-year moratorium on all forms of cloning. A competing bill-cosponsored by
Sens. Dianne Feinstein (D-Calif.), Orrin Hatch (R-Utah), Arlen Specter (R-Pa.),
and Ted Kennedy (DMass.)-that would allow and regulate therapeutic cloning was
given an excellent chance of reaching the magic number of 60 votes. How should
the Senate view the two Nature papers in the context of the emerging consensus
for the Feinstein bill? Is it still important to leave this avenue open to
scientists? Yes, more than ever.
Opponents of therapeutic cloning and stem cell research say that what is at
stake is the very idea of what it means to be human. I would put it rather
differently. At stake, right here, right now, is the sense that Americans have
that we are masters of our fate. That we can face the future with confidence.
That we can grow and change and thrive in a new world lying just beyond the
horizon.
This was the belief that drew millions of immigrants to our shores to embrace
lives they did not yet know. This same belief gave courage to those who headed
west in covered wagons. And it is the core belief that has made Americans the
people we arethe optimists and doers of the world, the people for whom the
frontier is a challenge, not a barrier.
The 21st century will be the century of biology. With information from the human
genome sequence and with stem cell technology, medicine will move from
treatments that are often clumsy, toxic, and just not very effective to disease
prevention, and to self-- repair. Devastating illnesses that have blighted our
lives could, one day, be stopped in their tracks. Such a paradigm shift is
possible only if we face the future with confidence and humility. And with a
commitment to plumb the depths of this new knowledge to extract the good and
avoid the bad.
No society venerates the law as much as ours. How strange then that so many see
the law as powerless in the face of biotechnology. How strange and how wrong.
Powerful technologies need to be guided-to be reined in. We can do that.
Therapeutic cloning unites two scientific discoveries that closed out the old
millennium and promise to transform the new one. The cloning of Dolly the sheep3
was breathtaking biology. Scientists had taken a cell that only knew how to do
and be one thing and tricked it into providing the instructions to reconstruct a
new organism. Then, in 1998, John Gearhart at Johns Hopkins and Jamie Thomson at
the University of Wisconsin published papers showing that they had derived human
pluripotent stem cells4,5-- cells that divided indefinitely in culture and had
the potential to produce all the cell and tissue types in the human body.
Therapeutic cloning to derive embryonic stem cells-because it could circumvent
the immune rejection elicited by therapies derived from generic stem cells-might
give us our own body repair kit. And, even if it does not make it into the
clinic as a practical and cost-effective tool, basic therapeutic-cloning
research could elucidate the still mysterious biological mechanisms that turned
one body cell into a sheep. We could then avoid the morally contentious embryo
stage altogether and, say, transform a skin cell directly into a neural cell to
cure our own Parkinson disease. The McKay research shows us that neurons derived
from embryonic stem cells can alleviate Parkinson disease-perhaps permanently.
An estimated 500,ooo Americans have this terrible disease, and another 50,000
cases are diagnosed yearly. Is it really right to turn our backs on them? The
moral case made by opponents of this research is based on the absolute sanctity
of the very early embryo-- a five-day-old ball of cells no larger than a grain
of sand. But what of the moral case to be made for the sick and the dying?
Americans have always stepped lightly from the past. It has not shackled us. It
has not prevented us from dreaming big dreams. For 18 months, I have been an
expatriate in Britain. Especially now, in the year of Queen Elizabeth's Golden
Jubilee, the irony of our disparate responses to therapeutic cloning has been
striking. So much of Britain-its culture, its governmental institutions, its
gentle way of life-- is anchored in the past. Yet, Tony Blair recently gave a
speech championing science as an engine for human progress. The United Kingdom
will forge ahead in all three areas-adult and embryonic stem cells and
therapeutic cloning-and is poised to lead the world.
The British have been pondering the moral and policy issues surrounding embryo
research for almost 20 years. When Dolly came along, when human embryonic stem
cells were derived in culture, when therapeutic cloning became a real
possibility, they had a legal framework within which to situate it all.
We, alas, do not. And we have suddenly realized that we have been flying by the
seats of our legal pants in areas that the British have tightly regulated for a
dozen years. It is far easier to venture into morally complex territory-which
therapeutic cloning certainly is-when there are clear rules, norms, and
procedures. It is not only easier, it is smarter and safer. The best way forward
is not criminalization of science out of fear. Nor is it a continuation of the
unregulated status quo. The Feinstein bill would allow cloning for therapies
(not reproduction), subject to strict scientific and ethical regulation. This is
the environment of British science. Americans and American science deserve no
less.
Scientists do not want to be our collective conscience; nor should they be. It
is up to us as a society to decide on permissible uses of technology. Evidence
of potential and of efficacy is coming thick and fast, but we are still a long
way from knowing which kinds of therapies-those derived from embryonic or adult
stem cells-will work for particular diseases. The widest range of options must
be kept open. Cutting science off at the knees-throwing away the benefits
because we have inchoate, science fiction-generated fears about sinister
applications at the bottom of slippery slopes-is what is criminal, what should
be criminal. Not therapeutic cloning. It should be allowed and regulated now.
References
1. J.-H. Kim et al., "Dopamine neurons derived from embryonic stem cells
function in an animal model of Parkinson's disease," Nature, 418:5o-6, July 4,
2002.
2. Y Jiang et al., "Pluripotency of mesenchymal stem cells derived from adult
marrow," Nature, 418:41-9, July 4, 2002.
3. I. Wilmut et al., "Viable offspring derived from fetal and adult mammalian
cells," Nature, 386:80-3,1997.
4. J. Thomson et al., "Embryonic stem cell lines derived from human blastocysts,"
Science, 282:1145-7,1998.
5. M.J. Shamblott et al., "Derivation of pluripotent stem cells from cultured
human primordial germ cells," Proceedings of the National Academy of Sciences,
95:13726-31, 1998.
ARLENE JUDITH KLOTZKO, a lawyer and bioethicist, is writer in residence at the
Science Museum, London, and adviser on science and society, Medical Research
Council Clinical Sciences Centre. She is editor of The Cloning Sourcebook and
author of the forthcoming A Clone of Your Own?, both published by Oxford
University Press.