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The Biology and Ethics of Human Stem Cell Research

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The Biology and Ethics of Human Stem Cell Research A Look at the Good, the Bad, and the Ugly Dr. Richard Holdeman, Indiana University rholdema_at_indiana.edu – PowerPoint PPT presentation

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Title: The Biology and Ethics of Human Stem Cell Research


1
The Biology and Ethics of Human Stem Cell Research
  • A Look at the Good, the Bad, and the Ugly
  • Dr. Richard Holdeman, Indiana University
  • rholdema_at_indiana.edu

2
What is your stem cell I.Q.?
  • Answer the following as True or False
  • 1. T F Stem cells hold great promise for the
    future of medicine.
  • 2. T F Stem cells have been used by doctors to
    treat disease for decades.
  • 3. T F The same technology used in stem cell
    research could be used to clone humans.
  • 4. T F President Bush has made research on
    human embryonic stem cells illegal.
  • 5. T F Human diseases have been successfully
    treated with stem cells taken from human
    embryos.

3
Stem Cell Biology
  • What are stem cells?
  • Stem cells are cells that have the remarkable
    potential to develop into many different cell
    types in the body. Serving as a sort of repair
    system for the body, they can theoretically
    divide without limit to replenish other cells for
    as long as the person or animal is still alive.
    When a stem cell divides, each "daughter" cell
    has the potential to either remain a stem cell or
    become another type of cell with a more
    specialized function, such as a muscle cell, a
    red blood cell, or a brain cell.
  • - NIH Website (http//stemcells.nih.gov/)

4
Stem Cell Biology
5
Stem Cell Biology
  • What classes of stem cells are there?
  • There are three classes of stem cells
    totipotent, multipotent, and pluripotent.
  • A fertilized egg is considered totipotent,
    meaning that its potential is total it gives
    rise to all the different types of cells in the
    body.
  • Stem cells that can give rise to a small number
    of different cell types are generally called
    multipotent.
  • Pluripotent stem cells can give rise to any type
    of cell in the body except those needed to
    develop a fetus.
  • - NIH Website (http//stemcells.nih.gov/)

6
Stem Cell Biology
7
Stem Cell Biology
8
Stem Cell Biology
9
Stem Cell Biology
Potential Benefits of Using Embryonic Stem Cells
  • Totipotent cells could theoretically be used to
    regenerate any tissue in the body.
  • Embryonic cells are easy to obtain from culture.
  • A virtually limitless supply of cells would be
    available in culture.
  • If enough cell lines were established and
    maintained in a bank, patients could be treated
    with cells that might not be rejected by the
    their immune systems.

10
Stem Cell Biology
Potential Problems with Embryonic Stem Cells
  • Difficulties establishing and maintaining lines
  • Difficulties obtaining pure cultures
  • Potential for tumor formation
  • Lack of proper differentiation
  • Genomic instability
  • Immune system rejection
  • Ethical considerations

11
Stem Cell Biology
  • To date there have been some encouraging results
    using embryonic stem cells to treat mice and
    monkeys, but there have been no clinically
    successful treatments in human beings.

12
Stem Cell Biology
  • What about using adult stem cells to treat
    disease?

13
Stem Cell Biology
  • Many of the technical hurdles have already been
    overcome without the ethical challenges
    surrounding embryonic stem cell research.
  • Adult Stem Cells, in fact, have been used to
    successfully treat 65 human diseases to date.

14
Stem Cell Biology
15
Stem Cell Biology
16
Stem Cell Biology
  • For the first time in 19 years, a Korean woman
    walks on her own after being treated with adult
    stem cells from umbilical cord blood.
  • - Korean Times (11/26/04)

17
Stem Cell Biology
  • For the first time researchers reconstitute a
    complete organ. New bladders were made by
    growing bladder cells from the patients on a
    biodegradable scaffolding.
  • - Reported in the Lancet (April, 2006)

18
Stem Cell Biology
  • Some scientists, who support the use of embryonic
    stem cells in research, have also pushed for the
    creation of new cell lines through a process
    known as somatic cell nuclear transfer (scnt).
    This technology has also been called therapeutic
    cloning.

19
Stem Cell Biology
20
Stem Cell Biology
21
Stem Cell Biology
  • Does therapeutic cloning lead to the cloning of
    human beings?

22
Stem Cell Biology
Reproductive Cloning
Therapeutic Cloning
23
Stem Cell Biology
  • Problems with therapeutic cloning
  • 1. 100 rate of death for the embryo.
  • Creation of embryos for the purpose of harvesting
    their cells.
  • Transplant rejection is still likely.
  • Process is inefficient (1 cell line/50-100
    oocytes).
  • Pressure will be exerted to allow embryos to
    develop longer to harvest specialized cells.
  • This is the same technology used for human
    reproductive cloning.

24
Stem Cell Ethics
  • This is an ethical issue.
  • Science is designed to tell us what is possible
    what we can do.
  • Science is not designed to tell us what is right
    what we should do.
  • To evaluate this technology one must employ some
    ethical system that comes from outside of science.

25
Stem Cell Ethics
  • Experimentation on human embryos violates the
    standards of the Nuremberg Code for research
    involving human subjects
  • No experiment should be conducted where there is
    an a priori reason to believe that death or
    disabling injury will occur
  • 7. Proper preparations should be made and
    adequate facilities provided to protect the
    experimental subject against even remote
    possibilities of injury, disability ,or death.

26
Stem Cell Ethics
  • Embryonic stem cell research, particularly
    therapeutic cloning, involves the creation of
    human life, which will be destroyed, for the
    purposes of harvesting cells for use in research
    or to treat disease in other individuals.
  • What is the status of the human embryo?
  • How is the embryos status weighed against the
    lives that might be saved by the technology?

27
Stem Cell Ethics
  • Results with adult stem cells have shown that
    there is a proven, effective alternative to
    embryonic stem cell research that is not burdened
    with ethical problems. This should make research
    with human embryos unnecessary and undesirable.

28
Stem Cells The Good
  • Regenerative medicine holds tremendous promise
    for the future.
  • Profound advances have already been made with
    adult stem cells.
  • Efforts to address the ethical issues surrounding
    this technology are being made (e.g., altered
    nuclear transfer or ANT).
  • The US government is not supporting research that
    involves the creation or destruction of embryos,
    but it is supporting research on existing
    embryonic stem cell lines.

29
Stem Cells The Bad
  • State and private money is continuing to fuel
    research that will involve the creation and/or
    destruction of human embryos.
  • The potential financial gains to be made by
    companies doing work on these technologies has
    put incredible pressure on scientists to push the
    envelope on this issue without due regard for the
    ethical issues involved.

30
Stem Cells The Bad
  • Out-and-out fraud has been committed by Hwang
    Woo-Suk, one of the leading scientists in this
    field, who was the first to claim that he had
    established human embryonic cell lines from
    clones (SCNT).

31
Stem Cells The Ugly
  • Politicians and others have made ridiculous
    claims about the prospects of embryonic stem cell
    research. Thus, giving false hope to people and
    families afflicted with debilitating diseases.

32
Stem Cells The Ugly
  • If we do the work that we can do in this
    country, the work that we will do when John Kerry
    is president, people like Christopher Reeve are
    going to walk, get up out of that wheelchair and
    walk again.
  • - Vice Presidential Candidate John Edwards on
    embryonic stem cells, 10/11/04.

33
Stem Cells The Ugly
  • This issue has become a political football with
    politicians lining up according to pro-life or
    pro-choice sentiments. The facts of the science
    have been lost in the process.

34
Stem Cells The Ugly
  • Scientists, who want to do science unfettered by
    ethical constraints, are decrying the current
    restrictions on embryonic stem cell research as
    major impediments to the scientific endeavor in
    general.

35
Stem Cells The Ugly
  • A second major issue sapping the confidence
    of US biomedical researchers is the increasing
    opinion that the present political leadership and
    certain influential parts of society appear to
    have little understanding of or respect for,
    science.
  • - Nobel Laureate Paul Nurse,
  • US Biomedical Research under Siege, Cell
    (1/13/2006).

36
Stem Cells The Ugly
  • The limited successes of embryonic stem cell
    research to date and the more encouraging
    developments with adult stem cells have not been
    reported accurately in the media, although as
    evidence continues to pile up, this may change.

37
Conclusion
  • Exciting developments in the field of
    regenerative medicine are now occurring.
  • Most of these are coming from non-controversial
    research using adult stem cells.
  • You have a responsibility to consider the ethics
    and the science involved and to act accordingly.

38
Conclusion
Regardless of your view of the human embryo, you
have to be able to make ethical distinctions.
  • What limits should there be on this technology?
  • Is reproductive cloning ok? How about human
    genetic enhancement? How about making
    human-animal chimeras? If any of these things
    are wrong, what makes them wrong?
  • Why use a technology that offends a significant
    percentage of the population when there are other
    alternatives available?

39
Conclusion How did you do?
  • Answer the following as True or False
  • 1. T F Stem cells hold great promise for the
    future of medicine.
  • 2. T F Stem cells have been used by doctors to
    treat disease for decades.
  • 3. T F The same technology used in stem cell
    research could be used to clone humans.
  • 4. T F President Bush has made research on
    human embryonic stem cells illegal.
  • 5. T F Human diseases have been successfully
    treated with stem cells taken from human
    embryos.

40
Stem Cell Resources
  • AAAS Stem Cell Report (http//www.aaas.org/spp/sfr
    l/projects/stem/index.shtml)
  • Bioethics.com (http//www.bioethics.com/)
  • The Center for Bioethics and Human Dignity
    (http//www.cbhd.org/)
  • Colson, Charles and Nigel Cameron, eds. Human
    Dignity in the Biotech Century A Christian
    Vision for Public Policy. Intervarsity Press
    (2004).
  • Do No Harm the Coalition of Americans for
    Research Ethics (http//www.stemcellresearch.org/)
  • NIH Stem Cell Resources (http//stemcells.nih.gov/
    )
  • Presidents Council on Bioethics
    (http//bioethics.gov/)
  • Smith, Wesley J. Consumers Guide to a Brave New
    World. Encounter Books (2004).
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