Transcript PowerPoint Presentation - Morality of Stem Cells

Morality of Stem Cells
Wise Young, Ph.D., M.D.
W. M. Keck Center for Collaborative Neuroscience
Rutgers University, Piscataway, NJ 08854-8082
http://carecure.rutgers.edu, http://sciwire.org
Stem Cells

Definition of stem cells
– Stem cells are “pluripotent” cells that can produce
many different kinds of cells. A fertilized egg is
“omnipotent”, i.e. can produce all cells.

Different kinds of stem cells
– Embryonic stem cells come from embryos (<6
weeks). Stem cells from blastocysts (2 weeks) are
virtually “immortal”.
– Fetal stem cells come from fetuses (> 6 weeks)
– Stem cells are present in some adult tissues,
including brain, spinal cord, and bone marrow.
Embryonic vs. Adult Stem Cells

Embryonic stem cells
– Embryonic cells are
pluripotent and virtually
immortal.
– Embryonic stem cells can
form tumors called
teratomas.
– Several methods are now
available to control
growth of embryonic
stem cells.

Adult stem cells
– Adult stem cells also
have the capacity to
produce many different
cell types, including
neurons.
– A person’s own stem
cells should be the best
source of cells for
transplantation
– Adult stem cells will
eventually substitute for
embryonic stem cells.
Embryonic Stem Cells
Adapted from the New York Times
18 December 2001
Fetal Stem Cells
Neurosphere
from rat brain
Nestin stain
BRDU stain
The Stem Cell Debate



On August 9, 2001, President George Bush announced that NIH
will fund human embryonic stem cell (HESC) research for the
first time. The research will be restricted to 72 cell lines derived
from surplus fertilized embryos before August 9.
Both opponents and supporters of HESC research are unhappy
with the ruling. Opponents believe that federal funding of
human ESC research will open a Pandora’s box leading to baby
and organ factories. Supporters believe that the restrictions will
hold back crucial research that will benefit millions of people.
Researchers have recently found that they can create cloned
embryos. Stem cells derived from such embryos have the same
genes and are an ideal source of stem cells for transplantation.
Congress, however, is considering a bill that would outlaw
making of cloned embryonic stem cells.
Importance of Stem Cells

Studies of human embryonic
stem cells will lead to major
advances in human biology
– Embryonic stem cell
research will provide critical
insights into mechanisms of
cell differentiation, growth,
and death.
– Understanding stem cells
may provide keys to why
people age.
– Limitations on the study of
human embryonic stem cell
research will hold back
biomedical research.

Human embryonic stem cell
therapies can save lives and
restore function of people
– Human embryonic stem cell
can replace damaged or lost
cells
– These include diabetes,
degenerative neurological
diseases, demyelinative
diseases, brain & spinal
cord injury.
– These conditions are the
most common and costly
causes of disability in the
United States.
Opposition to HESC Research

Killing human embryos is
unacceptable
– Use and study of human
embryonic stem cells will
require destruction of
human embryos.
– Killing human embryos is
unacceptable, no matter
how much good such
research will bring about.
– The facts that embryos will
die anyway and that many
people would benefit from
the therapies do not justify
killing embryos. The end
does not justify the means.

Embryonic stem cell
therapies are not necessary
– Adult and other sources of
stem cells, i.e. umbilical
blood or bone marrow stem
cells can be used.
– Many studies suggest that
stem cells from these
sources are beneficial in
animal disease models
– Embryonic stem cells may
form tumors whereas adult
stem cells have limited
growth potential and are
less likely to produce
cancers.
Common Misconceptions

Human embryonic stem cell
 The research will increase
research encourages abortions.
killing of human embryos.
– The proposed NIH research will
use frozen fertilized eggs, not
aborted fetuses.
– The fertilized eggs are used
with permission of the parents
who would otherwise discard
them.
– Availability of human embryonic
stem cells should reduce the
current need for and use of
human fetal tissues to treat
Parkinson’s disease and other
conditions.
– The proposed NIH research
will not create or clone
human embryos.
– Only fertilized eggs that
were already been created
for the purposes of in vitro
fertilization are used.
– Availability of this source of
stem cells should reduce
current unrestricted creation
and destruction of human
embryos for their stem cells.
More Misconceptions

Embryonic stem cells come
from embryos that can
become adults
– Thousands of fertilized eggs
are being discarded from
fertility and not being used
for research or therapy
– Many fertilized eggs have
been stored beyond the
time when they are suitable
for producing embryos.
– Many parents do not want
their eggs to be “adopted”
by others.

Embryonic stem cells come
from embryos with
recognizable body parts
– Embryonic stem cells come
from blastocysts (2 weeks),
little round balls of cells with
no discernible organs or
body parts.
– The blastocysts are never
implanted into a uterus.
– Embryos form only after the
notochord appears at about
2 weeks. Embryos become
fetuses at 6 weeks.
Current Situation

Current laws do not regulate
embryo production or use by
private companies
– Many companies produce
stem cells from human
embryos created for this
purpose.
– Some private organizations
are developing stem cells
from aborted fetuses.
– Some companies are even
cloning human embryos to
develop stem cell lines.

Most human embryonic stem
lines belong to private
companies.
– Companies therefore must
develop their own lines if
they want to do human stem
cell research.
– A “public” source of human
embryonic stem cells should
significantly reduce the
number of embryos that are
created and destroyed for
their stem cells.
Stem Cells vs non-Stem Cells

Stem cell therapies will
revolutionize medicine.
– The current generation of
doctors will be the first to
use stem cell transplants to
repair and replace tissues.
– Genetically modified stem
cells can deliver molecules.
For example, insulinsecreting cells may replace
life-time insulin injections.
– Stem cells are important
class of transplantable cells
because they are robust
and produce many cell
types.

Non-stem cells may be
better for some purposes
– Genetically modified
fibroblasts, for example,
have already been shown to
deliver gene products
– Mixtures of progenitor cells
that produce only one kind
of cell may be more easy to
control than stem cells.
– Some specialized cells may
have advantages over stem
cells. For example, Sertoli
cells have anti-immune
properties.
Slippery Slope Arguments

Federal funding of HESC
research may lead to a slide
down a slippery slope.
– A oft-stated fear is that
embryonic stem cell
research will go the way of
abortion. The United States
went from a complete ban to
abortions on demand.
– People feel that there are no
safeguard against a similar
slide towards a “Brave New
World” with embryo farms
and body parts for sale.

Limited stem cell availability
may lead to a slide down
another slippery slope:
– The stem cell lines created
before August 9 are not
sufficiently available nor
diverse for therapy
– HESC research will
continue in the private
sector and overseas where
embryo use is not regulated.
– Embryos are being created
for the purpose of stem cell
production.
Human Cloning
First human clone by
placing human nucleus into
a cow’s egg and growing it
to 32-cell stage.
Nov 1997
Scientific American article reporting the
“first” cloned human embryo showing a
fertilized cloned oocyte and cumulus
cells. Advanced Cell Technology
Nov 24, 2001
http://news.bbc.co.uk/hi/english/sci/tech/newsid_371000/371378.stm
http://www.sciam.com/explorations/2001/112401ezzell/
Therapeutic Cloning

Reproductive cloning
– The process of creating an
individual organism that is
genetically identical.
– Current method requires
somatic nuclear transfer
(transfer of nucleus of a
somatic cell to an oocyte)

Clonaid claims also to have
created first human clones and
plans for reproductive cloning.
- CNN, 27 Nov 2001
http://www.cnn.com/HEALTH/
Therapeutic cloning
– The process of creating
genetically identical cells for
therapeutic purposes.
– Many methods can be used,
including somatic nuclear
transfer & parthenogenesis
Religious Positions

Human embryonic stem cells are immoral
– The Catholic and Greek Orthodox Churches believe that
embryos are potential humans. Even if embryos are being
destroyed for other reasons, their use is immoral.

Research and use of early embryos is not immoral
– The Synod (Protestant) believes that human embryonic
research is not immoral if it occurs before implantation
– Islamic schools do not recognize early embryos as moral
persons and have no difficulty with use and study of them.

Life-saving research is a moral obligation
– The Jewish faith believes that saving human lives is a moral
obligation and a divine mandate as long as care is taken to
ensure that the process is fair to all parties involved.
Philosophical Positions

The “wisdom of repugnance” argument
– Dr. Leon Kass applied this phrase to therapeutic cloning,
meaning that we know, deep down, that it is immoral to
create human embryos to use them.

The “sanctity of life” argument
– Some philosophers have invoked the ”sanctity of life” as an
argument against using embryonic stem cells. This reduces
the question to our definition of life and a person.

The “respect for the embryo” argument
– Human life demands respect. While it is not disrespectful to
use an organ from a dead person, some argue that it is
disrespectful to create an embryo and kill it for its stem cells
U.S. Government Positions

In August 2000, NIH proposed to fund research on human
embryonic stem cells obtained from excess fertilized human
eggs that will be discarded by fertility clinics.
– These embryos were not produced for the purposes of research or
therapy. If they are not used for research, they would be discarded.

President Bush ruled that NIH can fund research on human
embryonic stem cells but only cell lines derived from fertilized
embryos before August 9, 2001
– This compromise ensures that no federal funding will support
destruction embryos for research or therapy
– President Bush strongly opposes human cloning or the creation
and killing embryos for the purposes of research or therapy.
– NIH has since identified about 72 human embryonic cell
lines created before August 9 and are eligible for study.
U.S. Legislative Positions

H.R.2747 Stem Cell Research for Patient Benefit Act of 2001.
– NIH research with human pluripotent stem cells, restricted to cell
lines available before August 9. Also funds an Institute of Medicine
study and establishes a Biomedical Advisory Commission.

S.1349 Responsible Stem Cell Research Act (2001)
–

$275 million for a National Stem Cell Donor Bank for qualified
human stem cells: human placenta, umbilical cord blood, organs or
tissues of adults, or unborn humans who died of natural causes
HR2505 Cloning Prohibition Act of 2001
– Criminalizes attempts, transport, or participation in human cloning
with a penalty of 10 years in prison and $1 million fine. Cloning is
defined as “human asexual reproduction, accomplished by
introducing nuclear material from one or more human somatic cells
into a fertilized or unfertilized oocyte”,
A Flawed Policy

Encourages private creation and use of embryos
– Private use of human embryos is unregulated.

Delays in stem cell therapies for people
– Available cell lines are not sufficient ly diverse for therapeutic
purposes
– Non-cloned stem cells are not immunologically compatible

Flight of research overseas
– Scientists and companies will move their research overseas
to more supportive environments

Banning of therapeutic cloning is not enforceable
– It is difficult to detect the origins of transplanted cells.
Extreme Positions
Only consequences matter
Prohibit all
human
embryonic
stem cell or
cloning
• Risk Analyses
• Consequences
• Alternatives
Ends do not justify means
Unrestricted
human stem
cell and
cloning
research
Scientific Consequences

Consequences of slowing HESC research
– Greater emphasis on adult stem cell technologies
– Limited human stem cell clinical trials for 3-5 years
– Flight of academic and commercial research to countries
that are more supportive of HESC work
– Intensified HESC research overseas

Consequences of federal funding of HESC research
– Availability of human stem cells for research and therapy
– Reduced creation and destruction of human and animal
embryos and fetuses for research and therapy
– Replacement of embryonic stem cells by adult stem cell
therapies in 3-5 years
Human Consequences

Restricted federal funding
and human stem cell lines is
slowing progress in moving
stem cell therapies to trial
– Millions of people are dying
from progressive disease,
I.e. Alzheimer’s, Parkinson’s
& Huntington’s, amyotrophic
lateral sclerosis.
– We cannot and should not
ask people with progressive
diseases and severe brain
and spinal cord injuries to
wait years for human stem
cells to reach clinical trial.

Limited availability of human
stem cells is encouraging
use of higher risk therapies.
– Genetically modified porcine
(pig) stem cells are being
transplanted into people to
treat stroke, brain & spinal
cord injury.
– Xenotransplants pose
special risks of animal
diseases passing to humans
– Human fetal tissues are
being transplanted to people
with Parkinson’s disease &
spinal cord injury.
Risk Analyses

Risks of slowing HESC research
– Alternatives are being applied (xenotransplants, fetal cell
transplants) with higher risks to individuals and society
– Slowing down biological research crucial for understanding
mechanisms of life, development, and death
– Delaying therapies for people who are dying and suffering
from severe disability
– Unregulated private sector creation and destruction of
embryos for stem cell production

Risks of federal funding of HESC research
– Slide down the slippery slope of condoning embryonic use
– The research will encourage cloning, baby-organ “factories”
Some Alternatives

Increase NIH funding of adult stem cell research
– This would strongly encourage scientists to develop
alternatives to embryonic stem cells
– It will provide alternatives to embryonic stem cell therapies
that will be developed overseas

Prohibit reproductive cloning but allow therapeutic
zygote cloning (<2 weeks) for stem cell production
– This allows federal regulation of stem cell production.
– This, however, will be opposed by anti-cloning groups.

Do nothing
– Companies will continue to clone and make stem cells
– Adult stem cells will be preferred over embryonic stem cells
A Better Compromise

Allow NIH to use stem cells derived from fertilized
eggs under a strict guideline of demonstrated need.
– This provides sufficient diversity for therapy.
– It will reduce the embryos use by private companies.

Ban implant of non-fertilized eggs into human uterus
– This ban on reproductive cloning is eminently enforceable.
– It would allow cloning of eggs for infertile women.

Allow therapeutic cloning with a sunset clause
– This provides a temporary solution until adult stem cells and
other alternatives can be developed
– It will prevent the flight of stem cell and cloning research
overseas
Conclusions


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Both sides of the debate share the same goal:
minimize creation and destruction of human embryos
while accelerating stem cell therapies
The current policy of limiting stem cells created
before August 9, 2001 will encourage unregulated
use of embryos while delaying stem cell therapies
Proposed anti-cloning legislation banning therapeutic
cloning is not enforceable, delays stem cell therapies,
and will drive scientists and companies overseas
A better policy would be to allow NIH to use new
stem cell lines, ban reproductive cloning, and allow
therapeutic cloning with a sunset clause