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The Brave New World of Cloning and Stem Cells Daniel P

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Title: The Brave New World of Cloning and Stem Cells Daniel P


1
The Brave New World of Cloning and Stem Cells
  • Daniel P. Sulmasy, OFM, MD, PhD
  • Department of Medicine Divinity School
  • The University of Chicago

2
Back to High SchoolDevelopmental Biology
Zygote
Morula 3d
Blastocyst 5 d
Implantation 6-7 d
14 d Embryo
21 d Embryo
28 d Embryo
8 weeks -- Fetus
3
In Vitro Fertilization
  • Egg retrieval
  • Sperm collection
  • Fertilization in glass
  • Maturation to embryo stage
  • Embryo transfer
  • Inefficiency
  • Pregnancy reduction
  • Spare embryos

4
In Vitro Fertilization
Zygote
Morula 3d
Blastocyst 5 d
5
As cells divide and the embryo grows
  • Chemical changes in DNA
  • Genes turned on and off
  • Telomeres and aging

6
Three basic kinds of cells (layers of the embryo)
  • Ectoderm
  • skin, brain nerves
  • Endoderm
  • gut, digestive organs
  • Mesoderm
  • muscle, bone, blood

7
Development continues in adults cells turn over
  • Blood cells last 120 days
  • Skin cells
  • Lining of the gut

8
Some tissues do not regenerate naturally
  • Brain and spinal cord
  • Heart muscle

9
Stem Cells
  • Rookie cells
  • Good young players
  • Can become shortstop, third baseman, or
    outfielder
  • Not yet committed
  • Can be trained

10
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
11
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

12
Stem Cells
  • Embryonic totipotent
  • Adult pluripotent
  • A misnomer
  • Umbilical cord blood
  • Bone marrow
  • Brain
  • Other tissues

13
Cloning
  • Somatic cell nuclear transfer
  • Even less efficient than IVF
  • Developmental problems
  • Process

Egg

Somatic Cell
Clonal zygote
14
Reproductive vs. Non-Reproductive
  • 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..

15
Awkward but Accurate
  • Research cloning
  • vs.
  • Cloning to bring babies to birth

16
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

17
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

18
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

19
Banning only cloning to make babies wont 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?

20
Why Stem Cells?
  • Not all body parts repair themselves
  • Repair of injury due to myocardial infarction and
    stroke
  • Degenerative diseases (e.g. diabetes
    Parkinsons)
  • Immune rejection

21
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

22
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

23
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24
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

25
Major counter-arguments
  • Before 14 days twinning can occur. Therefore
    there really isnt an individual person before
    that time.
  • Embryo is so small you cant 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.

26
Twinning
  • Since it can twin, isnt 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

27
Size shouldnt matter
  • As cogent as teenage boys in a locker room
  • Societal prejudice against the small
  • Growth hormone
  • Dr. Seuss Horton Hears a Who
  • A persons a person no matter how small

28
Against Orin Hatch
  • Embryo wastage many will die anyway
  • Reply
  • Infant mortality in developing nations
  • Death row
  • Jack Kevorkian

29
Leftover IVF embryos
  • There arent enough!
  • 400,000 in U.S.
  • Not all are viable
  • Need informed consent (lt 3)
  • Wont match recipients

30
If we dont pursue stem cells were killing all
the people who could be cured using them
  • Confuses the basic distinction between killing
    and allowing to die
  • All the money were 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

31
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.

32
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

33
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?

34
Moral status of the embryo whats 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

35
Only natural kinds have intrinsic value
Artifacts always have attributed value
36
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

37
Whats at stake, then?
  • The fundamental basis of human morality

38
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39
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40
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41
A phase sortal is not a kind sortal
zygote ? embryo ? fetus ? neonate ? infant
? toddler ? child ? adolescent ? young adult
? middle-aged ? older adult ? very old
42
Whats in the dish?
  • An individual member of the human natural kind at
    the earliest stages of development

43
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

44
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

45
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

46
Alternatives
  • Hematologic stem cells ? malignancy
  • Stem cells in brain, liver, elsewhere
  • Umbilical cord stem cells ? sickle cell, Krabbe,
    Hurlers
  • Bone marrow ? heart cells
  • Amniotic fluid
  • Biochemically de-differentiating adult stem
    cells (iPS cells)

47
Alternatives
  • Adult stem cells
  • Induced pluripotent stem cells (iPS cells)

48
Adult stem cells
  • Proven successes
  • Problem of de-differentiation
  • Problem of immortalization

49
iPS cells de-differentiating
Embryonic
Ectodermal
Cutaneous
Dermal stem cell
Dermal skin cell
Totipotent
Pluripotent
Committed
50
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

51
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

52
Picasso, Ciencia y Caridad, 1897
53
The Major Driving Force
54
Dignity is the intrinsic value of the members of
any natural kind that is (as a kind)
  • 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

55
Anti-speciesist
  • All members of any kind that has these qualities
    have dignity
  • E.T., angels, arguably other known species

56
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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