Stem Cells & Cloning: Ethical Questions

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The Brave New World of
Cloning and Stem Cells
Daniel P. Sulmasy, OFM, MD, PhD
Department of Medicine & Divinity School
The University of Chicago
Back to High School:
Developmental Biology
Zygote
21 d
Embryo
Morula
3d
Blastocyst
5d
28 d Embryo
Implantation
6-7 d
14 d
Embryo
8 weeks -- Fetus
In Vitro Fertilization
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Egg retrieval
Sperm collection
Fertilization “in glass”
Maturation to embryo stage
Embryo transfer
Inefficiency
Pregnancy “reduction”
“Spare” embryos
Zygote
Morula
3d
Blastocyst
5d
In Vitro Fertilization
As cells divide and the embryo grows
• Chemical changes in DNA
• Genes turned on and off
• “Telomeres” and aging
Three basic kinds of cells
(layers of the embryo)
• Ectoderm:
– skin, brain nerves
• Endoderm:
– gut, digestive organs
• Mesoderm:
– muscle, bone, blood
Development continues in adults:
cells “turn over”
• Blood cells last 120 days
• Skin cells
• Lining of the gut
Some tissues do not regenerate
naturally
• Brain and spinal cord
• Heart muscle
Stem Cells
• “Rookie” cells
• Good young players
• Can become shortstop, third baseman, or
outfielder
• Not yet “committed”
• Can be “trained”
Development and regeneration depend
on stem cells!
• Embryo
• Regenerating tissues
– e.g. blood
“juvenile” cells
Red cell
Red stem cell
Platelet
Platelet stem cell
Lymphocyte
Hematopoetic
stem cell
Monocyte
White stem cell
Polymorphoncuclear
white cell
“Plasticity” of stem cells
• “Totipotent” – can develop into any kind of
cell, even a new individual organism (i.e.,
a twin)
• “Pluripotent” – can develop into a variety
of tissue types
• “Committed” – can develop only into one
tissue type
Stem Cells
• Embryonic – “totipotent”
• Adult – “pluripotent”
– A misnomer
– Umbilical cord blood
– Bone marrow
– Brain
– Other tissues
Cloning
• “Somatic cell nuclear
transfer”
• Even less efficient
than IVF
• Developmental
problems
Process
Egg
+
Somatic Cell
Clonal zygote
“Reproductive” vs. “NonReproductive”
• Begs the question –
• Assumes that making embryos is not
reproduction unless gestated
• But a major point of contention is whether
or not making a human embryo is
reproducing a human being
• So…..
Awkward but Accurate
“Research cloning”
vs.
“Cloning to bring babies to birth”
Why Cloning?
• To bring babies to birth
– Total infertility
– Gays and lesbians
– “Reproductive freedom”
• Research
– Run out of spare embryos for stem cells
– Immuno-compatible stem cells or fetal tissue
– Pure basic research
Scientific problems with cloning
• Not yet done in human beings (?)
– Hwang was a fraud
• Poor success rate in other animals
– 1 in 277 for Wilmut to make Dolly
• Not enough animal experiments
• Genetic abnormalities: “old wine in new
wineskins”
• Premature aging
Moral problems with cloning to
bring babies to birth
• “Offense to Human Dignity”
– Blurs the line between natural kind & artifact
• Role problems: my twin or my son?
• Begetting vs. manufacture
• Threat to human freedom
Banning only cloning to make
babies won’t work:
• Once research cloning is allowed, cloning
to bring babies to birth will follow
• All it takes is implantation, as in IVF
• Once in the freezer, how tell if cloned?
Why Stem Cells?
• Not all body parts repair themselves
• Repair of injury due to myocardial
infarction and stroke
• Degenerative diseases (e.g. diabetes;
Parkinson’s)
• Immune rejection
Possible sources of stem cells
• “Adult” stem cells (e.g. blood stem cells for
chemotherapy)
• Umbilical cord blood (e.g. Krabbe or
Hinter-Hurler)
• Amniotic fluid
• Fetal tissue (e.g. Parkinson)
• “Spare” embryos
• Cloned embryos
Moral issues
• Stem cells per se are not problematic
• Everyone wants to help treat disabling
human conditions
• No one is seriously opposed to all stem
cell research and therapy
• Moral status of the human embryo
• Practically speaking, the clinical use of
embryonic stem cells entails cloning
Basic objection to embryonic stem
cells
• Develop (or create de novo) a new human
being for the express purpose of killing
that human being in order to extract cells
• Violates the Kantian principle that every
human being is an end in him/herself and
ought never be treated as a means only
Major counter-arguments
• Before 14 days twinning can occur. Therefore there
really isn’t an individual person before that time.
• Embryo is so small you can’t see it without a
microscope. How could that be a person?
• IVF embryos will die anyway. Why not make the best of
a bad job?
• If we can help people, then not using stem cells will kill
even more people.
• What will all those people with so-called principles do
once it has been proven that embryonic stem cells can
cure people.
Twinning
• Since it can twin, isn’t an individual
• Reply:
– One ameba  two amebas
– If a legitimate argument, then internally
contradictory:
• none of us would be persons, since we could also
potentially be twinned through cloning
Size shouldn’t matter
• As cogent as teenage boys in a locker
room
• Societal prejudice against the small
– Growth hormone
• Dr. Seuss – Horton Hears a Who
– “A person’s a person no matter how small”
Against Orin Hatch
• “Embryo wastage” – many will die anyway
• Reply:
– Infant mortality in developing nations
– Death row
• Jack Kevorkian
Leftover IVF embryos
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There aren’t enough!
400,000 in U.S.
Not all are viable
Need informed consent (< 3%)
Won’t “match” recipients
“If we don’t pursue stem cells we’re killing all
the people who could be cured using them”
• Confuses the basic distinction between killing
and allowing to die
– All the money we’re spending on all stem cell
research could provide clean water in the
developing world
• Ignores the fundamental principle that the end
ought not justify the means
– Philippa Foot – serum for five
What will become of their principles?
• If the moral basis for public policy is that
people will abandon their principles
whenever it is in their self-interest, then
there is no moral basis for public policy.
Problems with embryonic stem cells
• “First do no harm”
• Numerous genetic abnormalities in clones
• Potentially harmful to a recipient of stem
cells derived from clones
• Embryonic stem cells tend to form tumors
-- teratomas
Slippery slope:
• Eugenics
• Egg donors:
– 17 million US diabetics (type 1 + type 2)
– 250 eggs per stem cell line (if as easy as
sheep)
– 4.2 billion eggs for all US diabetics
– Where will these eggs come from?
Moral status of the embryo: what’s
in the dish?
• Property?
– Commodification and human dignity
• Just a tiny bit of “tissue,” not a person
– Further than Roe v. Wade
– No “privacy” argument
• Individual member of the human natural
kind in the initial stages of development
• Only natural kinds have intrinsic
value
• Artifacts always have attributed
value
Intrinsic Human Dignity
• The value we have by virtue of being the
kind of thing that we are – i.e. – a human
being
• The foundation of all human rights
• The basis for all interpersonal morality
What’s at stake, then?
• The fundamental basis of human morality
A phase sortal is not a kind
sortal…
zygote  embryo  fetus  neonate  infant 
toddler  child  adolescent  young adult 
middle-aged  older adult  very old
What’s in the dish?
• An individual member of the human
natural kind at the earliest stages of
development
The intrinsic value of the kind of
thing that is in the dish:
• Whatever is in the dish is the same kind of
thing, whether it is to be brought to birth or
disaggregated for its stem cells
• Therefore it must have the same intrinsic
value regardless of the purposes for which
it is used
Dignity and Embryonic Stem Cells
• Troubling because obtaining these cells by the
destruction of embryos tends to blur the
distinction between an artifact and a natural kind
• To the extent that human beings are created de
novo, especially for the benefit of others, they
tend to be considered artifacts and this explains
our worries about dignity
• Explains “begetting vs. manufacture”
Is the disaggregation of a cloned
human embryo compatible with
respect?
• To clone a human embryo (or create
through IVF) with the premeditated plan of
taking it apart, killing it, and using its parts,
even for a noble cause, cannot
conceivably be considered ‘respectful’
Alternatives:
• Hematologic stem cells  malignancy
• Stem cells in brain, liver, elsewhere
• Umbilical cord stem cells  sickle cell,
Krabbe, Hurler’s
• Bone marrow  heart cells
• Amniotic fluid
• Biochemically “de-differentiating” adult
stem cells (iPS cells)
Alternatives
• Adult stem cells
• Induced pluripotent stem cells (iPS cells)
Adult stem cells
• Proven successes
• Problem of de-differentiation
• Problem of immortalization
iPS cells: “de-differentiating
Embryonic
Totipotent
Ectodermal
Cutaneous
Pluripotent
Dermal stem cell
Committed
Dermal skin cell
iPS cells
• First accomplished in humans 2 years ago
• “Toggling” no more than 4 genes with
transcription factors (Oct3/4; Sox2 critical)
• Appear to be immortalized
• Can be “re-differentiated” into retinal cells, heart
muscle cells
• The problem of viral vectors
– Has been overcome in mice (valproic acid)
• Still, all the problems of embryonic stem cells
(e.g. tumors) if pushed back to the embryonic
stage
Prudence
• Even if unconvinced by my arguments:
• When faced with two alternatives
– One that raises profound moral questions
(embryonic)
– Another that is morally unobjectionable
(adult stem cells or iPS cells)
• Prudence dictates choosing the morally
unobjectionable means
Picasso, “Ciencia y Caridad,” 1897
The Major Driving Force
Dignity is the intrinsic value of the members
of any natural kind that is (as a kind):
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Rational
Affective
Mutually interdependent/social
Aesthetic
Worshipping
Free willing
Capable of love
A sense of humor
Able to grasp the finite and the infinite
Practically moral
• Independent deliberation
• Coordinated action
• Mutual binding of wills
Anti-speciesist
• All members of any kind that has these
qualities have dignity
• E.T., angels, arguably other known
species
Conclusions
• Stem cell therapies have great promise
• Cloning, even for stem cells, is deeply
morally problematic and impractical as
therapy
• Human embryonic stem cells for therapy
also raise deep moral problems
• Adult stem cells and iPS cells appear able
to fill clinical needs without raising moral
problems
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