based on
Testimony offered on
S25, An Act Promoting
Stem Cell Research
Presented to the Joint
Committee on Economic
Development and
Emerging Technology
Wednesday, February 16, 2005
Marjorie Clay, PhD
Medical Ethicist
UMass Medical School
What are stem cells?

Cells that have the ability to divide for
long periods of time.

Cells that are developmentally “plastic”:
they can take different pathways and
develop different cell types.
Types of stem cells
Totipotent stem cells can give rise to a fully
functional organism. . . .
. . . . AND to every cell type in the body.
Pluripotent stem cells can give rise to virtually
any tissue type. . .
. . . . but NOT to a fully functional organism.
Levels of differentiation
In late 1998, James
Thompson at UWMadison discovered
how to isolate and
culture hES cells.
Sources of stem cells




Adult Stem Cells
Embryonic Stem Cells
Embryonic Germ Cells
Induced Pluripotent Stem Cells
Adult Stem Cells
 Haven’t been isolated for all tissue types
 Present in small quantities
 Difficulties in isolation and purification
 Numbers and quality decrease with age
 Differentiate into a narrower range of
cell types
Induced Pluripotent Stem Cells (iPS)
• iPS are a type of pluripotent stem cell
artificially derived from a nonpluripotent cell, typically an adult
somatic cell.
• iPS were first produced in 2006 from
mouse cells and in 2007 from human
cells.
• iPS are not totipotent and do not
involve the destruction of an embryo.
James Thomson
Shinya Yamanaka
Induced Pluripotent Stem Cells (iPS)
• Master regulator genes (turn other genes on
or off)
• Oncogenes might be turned on. [Feb. 2008]
• Retroviruses can slip other genes into the
chromosomes.
Sources of Embryonic Stem Cells
 Embryonic stem cell lines
 Excess embryos from IVF clinics
 Embryos created for research by IVF
 Therapeutic cloning
Starting an embryonic stem cell line
We start with this. . .
. . .and end with this:
Ethical problem: derivation
Is it unethical to harvest stem cells?
Is it murder,
as some
opponents of
stem cell
research have
argued?
Should we treat blastocysts as persons?
Congregation for the Doctrine of the Faith: Instruction on Respect
for Human Life in its Origin and on the Dignity of Procreation
“The
being
is to begeneration,
respected and
“Thushuman
the fruit
of human
from the
treated
as a person
from the moment
first moment
of its existence,
that is toofsay
conception;
and therefore
from
same
from the moment
the zygote
hasthat
formed,
moment
as a person
mustthat
be is
demandshis
therights
unconditional
respect
recognized,
which in
the first
is
morally dueamong
to the human
being
in hisplace
bodily
the
right of every innocent human
andinviolable
spiritual totality.”
being to life.”
Some observations

The ethical theory used by some opponents
of stem cell research is called natural law
theory.

It is based on an Aristotelian view of
science, biology, etc.

Our knowledge of biology has changed a
great deal since Aristotle!
First, there is no “moment” of conception.
It takes about 24 hours to fertilize an egg.
Reaching this two-cell stage takes about
30 hours total.
Reaching this morula stage takes about
40 hours total.
None of these zygotes have the potential to
become human beings because they are not
implanted in a uterus.
Second, until implantation, no “embryo” exists.
Reaching the blastocyst stage takes between
5-6 days total.
Many complex changes must occur before
implantation is complete (at about 13 days).
Ethical implications

There is no single ‘moment’ of conception.

Without a “host,” fertilized eggs neither are -nor can they become -- persons.

Because a blastocyst created for research
purposes will not be implanted in a uterus, it is
not a potential person.
A cell taken from a blastocyst before
implantation is not -- nor can it become -- a
person. [Taken from the inner cell mass and so
is only pluripotent].

Should we treat blastocysts as persons?
Congregation for the Doctrine of the Faith: Instruction on Respect
for Human Life in its Origin and on the Dignity of Procreation
“Thus the fruit of human generation, from the
first moment of its existence, that is to say
from the moment the zygote has formed,
demands the unconditional respect that is
morally due to the human being in his bodily
and spiritual totality.”
Ethical implications

Not all fertilized eggs become implanted in a
uterus; some are passed in menstruation. Does
anyone treat these fertilized eggs as if they were
persons?

What would it mean to give them ‘the unconditional
respect that is morally due to the human being in his
bodily and spiritual totality’?

Would we allow cryopreservation of zygotes if we
thought they were living persons?
What follows from those observations?

We don’t treat zygotes as human persons and
there are good scientific reasons why we don’t.

Until implanted in a uterus, zygotes do not have
the conditions necessary for development.

Nor do we have a moral obligation to provide
those conditions.

If we did have an obligation, it would
require “rescuing” fertilized eggs passed in
menstruation.
Sources of Embryonic Stem Cells
 Embryonic stem cell lines
 Embryos created for research by IVF
 Excess embryos from IVF clinics
 Therapeutic cloning
Does this “argument” make sense?
If we thought
they were
human
persons,
would we
“pitch ‘em”?
 400,000 fertilized eggs have been frozen and
stored since the late 1970s.
[American Society of Reproductive Medicine study]

In July 2002, the DHHS designated $900,000±
to support “embryo adoption.”

Many ethicists oppose the use of this term
because it is inaccurate and misleading:
• a fertilized egg is not an embryo
• misapplication of adoption law
• substitutes labels for argument.
Sources of Embryonic Stem Cells
 Embryonic stem cell lines
 Excess embryos from IVF clinics
 Embryos created for research by IVF
 Therapeutic cloning
Somatic cell nuclear transfer
Remove DNA from egg cell; insert a body (somatic) cell.
Does therapeutic cloning start us down
a slippery slope . . . .
. . . to reproductive cloning?
Source: “Stem Cells: A Primer”
Developmental Research
90% of what we know about early human
development is inferred from studies on
mouse embryos.
Embryonic stem cells provide a window
into early human development that
researchers have never had before.
Potential Clinical Uses
 Identify teratogens
 Drug toxicity tests
 Regenerative medicine
 Cardiomycetes for heart disease
 Islet cells for diabetes
 Neural cells
 Immunodeficiency
The target diseases/conditions






Juvenile Diabetes
Multiple Sclerosis
Parkinson’s Disease
Alzheimer’s Disease
Leukemia
Arthritis






Muscular Dystrophy
Lou Gehrig’s Disease
Spinal Injuries
Burns
Heart failure
Stroke
The Benefits of Stem Cell Research
“We believe that not to develop the technology
would do great harm to over 100 million patients
in the United States alone who are affected by
diseases potentially treatable by the many
medical applications of hES cells.”
Thomas B. Okarma
Geron President and Chief Executive Officer
“Human Embryonic Stem Cells: A Primer on the
Technology and Its Medical Applications”
Drug Development and Testing
http://www.news.wisc.edu/9064.html
hES Cell-derived cardiac cells spontaneously organize
themselves and begin to beat.
Tissue/Cells for Therapy

MS results from a degradation of
myelin, resulting in the interruption
of electrical signals traveling down
nerve fibers.

Shiverer mice have an MS-like
condition, and so are used as a
model to study potential MS
treatments.

Researchers injected stem cells
from a healthy mouse into the
brains of shiverer mice. The stem
cells multiplied, migrated
throughout the brain, and became
myelin-producing cells. Injected
mice stopped shivering.

If injected young enough, shiverer
mice never start shivering.
Impatient Patients
• Stem cells may be able to
replace damaged cells in
the body.
• Today: lymphoma, leukemia
• Future? Parkinson’s,
Alzheimer’s, diabetes...
The real ethical issues

The distinction between public and private
sectors and the question of oversight
 Creating a “level playing field”
 Limiting applications and participants
(e.g., control misuses of power)
Minimizing the occurrence of ‘mistakes’
and unintended consequences
The real ethical issues (con’d)
 Questions raised by commercialization
(e.g., patents, ownership, profit,
corporations, shareholders and other
third-party sponsors)
 Justice: access and distribution
In Georgia, 60% of urban white women age 40+
but only 0.5% of rural African-American women
age 40+ used prenatal genetic testing.
Will using stem cells cause us to devalue
life?
Uniformly
applied
regulations
should do
much to
prevent this
outcome.
Conclusion




Immanuel Kant -- “Ought implies can.”
“Technological imperative” -- “Can
implies ought.”
Ethical position -- “Not all that we can
do but only what we should do.”
All things considered, promoting stem cell
research is an ethically sound decision. It is
something we should do: we owe it to the
100+ million people who might be helped.