Transcript Stem Cells and Cloning: Ethical Dilemmas in

Stem Cells and Cloning: Ethical
Dilemmas in Medicine and Science
What are stem cells?
Stem Cells
• Type of cell from which all other cells in our
body arise from
• Two defining characteristics:
– Can divide and continuously renew themselves
both in vivo and in vitro
– Ability to develop into specialized cells such as
muscle, nerve, skin, or pancreatic cells
• Potential to cure many illnesses!
Stem Cells
• Totipotent (spores, zygotes)
– Can produce all differentiated cells in an organism
including extra-embryonic tissue
• Pluripotent (inner mast cells)
– Can differentiate into any of the three germ layers
(endoderm, mesoderm, ectoderm)
• Multipotent (adult stem cells)
– Can differentiate into a single family of cells
• Oligopotent, Unipotent
Why have stem cells been so
controversial over the past several
years?
Stem Cell Controversy
• Ethical debate concerning the creation
treatment, and destruction of human embryos
• Harvesting pluripotent stem cells from human
embryos kills them
• When does life begin? Does the embryo have
rights?
But now we have new ways to
acquire stem cells!
iPS Cells
• Induced Pluripotent Stem Cells
• Adult cells can be reversed engineered to behave
like pluripotent stem cells
• In 2006, a Japanese team lead by Shinya
Yamanaka was able to reprogram adult skin stem
cells to behave almost like embryonic stem cells
(won the Nobel Prize in 2012 for the importance
of this work to regenerative science.
• In 2013, a Spanish team repeated this in vivo and
they reverted to an even early state of
development
Does this mean the debate is over?
No.
• Unlike hES cells, iPS cells can be derived from the
somatic tissues of a wide variety of living donors.
• A living donor means many more ethical issues
arise.
– The re-contacting and tracking of donors
– What to do with incidental findings that may impact a
living donor’s health
– Extent and scope of donors’ reach-through rights to
the downstream research uses and commercial
benefits of their genetically matched iPS cell lines
• Not a new issue.
Henrietta Lacks and HeLa Cells
• After 5th child, diagnosed with cervical cancer
• During radiation, samples of cancerous and
healthy cells were removed without permission
• Died from cancer in October of the same year
(1951)
• Autopsy revealed her cancer had metastasized
throughout her body
Henrietta Lacks and HeLa Cells
• The cells that had been harvested were given
to Dr. George Otto Gey
• He discovered that they continued to grow
• Prior to this, scientists spent more time trying
to keep cells alive than studying them
• Named immortal cell line HeLa
• Sold around the world to scientists
Henrietta Lacks and HeLa Cells
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Used by Jonas Salk to develop the polio vaccine
HeLa cells were the first to be cloned in 1955
Put into mass production
Mailed across the world for cancer, AIDS,
radiation, gene mapping, and other research
• Family knew nothing about this.
Henrietta Lacks and HeLa Cells
• Family began receiving calls in the 1970s by
scientists who wanted blood samples from
them to determine their genetics
• Huge ethical debate—racism, commercial rights
• Morehouse School of Medicine donated
headstones so that Henrietta and her daughter
would not be buried in unmarked graves
Even with controversies, stem cell
research has important
applications that can’t be ignored.
Are iPS cells really the same as ESCs?
• Heavily debated
• ESCs are still the gold standard for which all others are
compared
• By deriving and studying stem cells that are genetically
matched to diseases such as Parkinson disease and
juvenile diabetes, researchers hope to map out the
developmental course of complex medical conditions to
understand how, when, and why diseased specialized
cells fail to function properly in patients.
• One more viable way to produce disease-specific stem
cells.
Somatic Cell Nuclear Transfer (SCNT)
• Research cloning
• May be able to produce human ESCs that are
genetically matched to the patient and his or
her particular disease
• SCNT has worked recently in non-human
primates to produce cell donor–matched
primate stem cells
• Human SCNT for disease research is, in
principle, possible
Somatic Cell Nuclear Transfer (SCNT)
• Cloning is largely controversial
• Limited funding available
• Unpredictable with minimal success
Dolly
• The first
successfully
cloned
mammal
Cloned Animals
• Dolly
– 277 eggs, 29 embryos, 3 lambs, 1 Dolly
• Frogs
– First cloned animals were frogs
– Not 1 adult has ever been made
• Dozens of other types of animals have been
cloned or attempted to be cloned.
What about cloning humans?
Ethical, Legal, Social Issues
• Should anyone have the right to have children
no matter how they are created?
• Is human cloning, playing with nature?
• Does therapeutic cloning justify destroying an
embryo?
• Who is the parent of the clone?
• What would the social challenges be of the
cloned child be as he/she grows up?
• How should cloning research be regulated?
Why would we clone humans?
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Source of stem cells
Growing new organs
Replacing deceased children
Immortality?
Raelians
As of August 2008, they had over
70,000 members in 97 countries.
Raelian Beliefs
• Raëlians seek to both genetically clone
individuals and rapidly accelerate growth of
the clone to adulthood through a process like
guided self-assembly of rapid expanded cells
or even nanotechnology and then transfer the
mind and personality of the donor into the
clone.
• Raelians believe humanity can attain eternal
life through the science of cloning.
• [Video]
Clonaid
• Human cloning company founded in 1997
• Mark Hunt, West Virginia politician
– Wanted to clone his deceased son
– Donated $500000 for research equipment
• In 2002, Boisselier announced the production
of a successful live-borne clone, named Eve,
for an infertile couple.
• Refused to provide proof
Speaking With Congress
• Boisselier invited to speak with congress in
March 2001
• Rael (Claude Vorilhon) brought with her.
• Claude Vorilhon told lawmakers that banning
the development of human cloning was
comparable to outlawing medical advances
such "antibiotics, blood transfusions, and
vaccines."
What do you think?