The Use of Stem Cells for Therapeutic Purposes: A Case Study for
Middle School Students
Bryan Nicklaus Brown, BS
NIH NSRA F31 Predoctoral Fellow
McGowan Institute for Regenerative Medicine
Department of Bioengineering
University of Pittsburgh
AND
Rosa Lynn Pinkus, PhD
Professor Medicine/Neurosurgery
Associate Director, Center for Bioethics and Health Law
Director, Consortium Ethics Program
University of Pittsburgh
Note to Teachers: This module utilizes and builds upon the moral and ethical
concepts and problem solving methods described in “The Use of Animals for
Educational and Research Purposes: A Case Study for Middle School Students”.
Teachers are encouraged to use the previous module as a simple “example” case
before asking students to consider the more complex ethical dilemma presented in this
module. Also, teachers are cautioned that this module deals with more complex and
“adult” issues than the previous module. As such, you should tailor the specific details
of the case to the demographics of your class.
Joe is considering applying for graduate school. He knows that he really wants to
work on something that will help people in a big way and sets about looking for schools that
are involved in research that has the potential to make a real clinical impact. In his search, he
comes across a university that is pioneering the use of cardiac tissue engineering to develop
new therapies to help patients with heart disease. Specifically, the research is directed at
helping people who have suffered heart attacks and lost heart muscle function. Joe knows
that heart disease is not only a big problem, affecting millions of patients in the United States,
but also that it runs in his family. In fact, his uncle suffered a heart attack less than a year
ago.
With this in mind, Joe decides that he would like to get a PhD in biomedical
engineering and focus his thesis research in the cardiac tissue engineering lab of the
university he has identified.
His grades are excellent as are his GRE scores. His undergraduate advisor writes him
supportive letters of recommendation. He applies to three schools and gets an interview at the
university. In preparing for the interview, he does more background research about the
laboratory that is doing the cardiac work. He learns that they use embryonic stem cells and
collagen to repair damaged heart muscle following a heart attack. The research is considered
to be very promising, and a number of scientific journals, newspapers, blogs, and TV
programs begin to highlight the promise it holds for patients. Joe’s family, friends and
neighbors have seen these reports and are excited that Joe may actually become part of the
team that is working on the project.
1
In particular, Joe’s uncle has become interested in heart tissue engineering since he
recovered from his heart attack. He sends Joe this article about the work being performed in
the lab at the university to which he is applying:
Embryonic Stem Cell - Based Tissue Engineering May Help Repair Damaged Heart Muscle
Embryonic stem cells may hold the key to
regenerating damaged heart muscle, when
transplanted within a 3-dimensional scaffold
into the infracted heart, according to a new
study coming out in June in the Journal of
Heart and Lung Transplantation. In the study,
embryonic stem cells were more successful in
restoring heart muscle when transplanted
within a 3-dimensional matrix into damaged
hearts in an animal model of severe infarction.
The new study addresses several problems that
have plagued previous attempts to regenerate
damaged heart muscle, according to Theo
Kofidis, M.D., who has an active tissue
engineering program at Stanford.
"Tissue engineering holds out promise of
truly healing the heart after congestive heart
failure," said Dr. Kofidis, lead author of the
study and research fellow in cardiothoracic
surgery at the Falk Research Center at
Stanford University Medical School in
Stanford, Calif. "There are 460,000 cases of
congestive heart failure in the United States
each year and the preeminently efficient
treatment we have at this time is heart
transplantation. Through tissue engineering we
could actually restore the function of the heart
by replacing large portions of the damaged
heart muscle by a bioartificial one."
Kofidis and his colleagues had been
working with bone marrow stem cells, but
these cells were not able to become heart
muscle cells and regenerate the heart. "In our
most recent studies we showed that mouse and
human embryonic stem cells improved heart
function, had superior survival within the heart
– weeks later we still saw improved heart
function – and had definitely differentiated
into heart muscle cells," he said. "We inserted
a bioluminescent marker (what causes fireflies
to luminesce) into our stem cells and were able
to see that they engrafted in the living organ."
There are two components to tissue
engineering, according to Dr. Kofidis: the cells
that will replace the dead cells and regenerate
the organ, and the supporting framework that
will distribute the cells evenly and maintain
the 3-D shape necessary for proper functioning
of the organ.
"We have been working for a long time on
developing the ideal scaffolding to support the
injected cells and the architecture of the
organ," said Dr. Kofidis. "We have identified a
collagen, a mesh-like structure, that we have
manipulated into an excellent framework. The
cells distribute evenly into this meshwork,
which is a liquid. Then, due to its liquid nature,
we are able to inject it into the heart through an
endoscope, with much less surgical trauma
than if we had to open the chest to reach the
heart. This liquid tissue solidifies at body
temperature.
"We let Nature integrate this tissue," said
Dr. Kofidis. "We inject it as a liquid and let it
consolidate within the affected heart where it
supports the geometry of the damaged region.
One of the problems in congestive heart failure
is that the wall of the heart's chamber becomes
thinner and thinner as the heart muscle cells
die off. Eventually it is too weak to beat
properly."
With the integration of the human
embryonic stem cells and their patented
supporting framework, Kofidis hopes that they
have the two pieces of the puzzle needed to
successfully integrate regenerative cells into
the damaged heart, maintain its geometry and
restore its function.
"A word of warning may be appropriate
here. Only a few years ago many people
thought an artificial heart was around the
corner," said Dr. Kofidis. "We now know that
there are many problems to overcome and
questions to answer. In order to reproduce
nature with the highest possible fidelity we
have to build something that follows the
natural architecture of the heart.”
1
Note to Teachers: This is only one of many examples of scientists using stem cells to
develop regenerative therapies. Teachers are encouraged to supplement the above
article with additional articles that further illustrate the use of stem cells in research,
describe the ethical concerns associated with their use, or involve local
researchers/patients in order to provide students examples to which they can relate.
1
Article adapted from: Embryonic Stem Cell - Based Tissue Engineering May Help Repair Damaged
Heart Muscle. ScienceDaily (May 18, 2004). Online:
http://www.sciencedaily.com/releases/2004/05/040518075414.htm
2
A few weeks before his interview, Joe’s uncle tells him how excited he is that Joe
might soon be participating in the kind of research he read about in the article and wonders if
a regenerative medicine treatment might have helped to speed his own recovery?
Joe says “I think that the research that they are doing is great. It sounds like the
embryonic stem cell treatment they are using is working and can help people. I really hope
that I can get into the lab.”
Peggy, overhearing the conversation that Joe is having with their uncle, becomes
interested. She has been learning about the reproductive and developmental process in her
science class. She knows that, during reproduction, an embryo is a cluster of cells that
eventually goes on to become a baby animal, or person. She is confused, though, about what
exactly a stem cell is, and how they get them from an embryo to use in research and asks Joe
to explain.
Note to Teachers: This is a good opportunity to stop and do an activity related to the
development and biology of reproduction/embryos, if it has not already been covered
in class. This is also a good opportunity to discuss the source of the embryos for
research purposes (i.e. embryos remaining from in vitro fertilization). Teachers are
referred to ??? (Dr. Pinkus, can you please fill in the name/pg number of the NIH
materials that we have for this?) for more detailed information on this subject. You
are encouraged tailor the content of this discussion to fit the maturity/demographics
of your students.
Joe explains, “You’re right. An embryo is a cluster of cells that has the potential to
continually divide and differentiate to become an animal or a human. Scientists are able to
collect cells from a part of an embryo that have the ability to develop into a variety of
different types of cells in the body. These cells are called embryonic stem cells”
“Are all of the cells in an embryo stem cells?” asks Peggy.
“No, only some of the cells in an embryo are stem cells. The other cells aren’t.
Scientists have to use special techniques to separate the stem cells from the other cells.”
“Oh. So, what’s the difference between the stem cells and the other cells?”
“That’s a very complicated question, but let me see if I can answer it. Stem cells are
unspecialized cells that can make exact copies of themselves by dividing and can also turn
into more specialized cells like bone cells or skin cells. Other cells are already specialized
cells and can’t become another type of cell. For example, a cell that has already turned into a
red blood cell can’t become a skin cell, but a stem cell can become a blood cell or a skin cell.
Does that answer your question?”
“I think I get it. But, what do stem cells do, exactly? Why are they so important?”
“Well, like I said, they can create copies of themselves and turn into other types of
cells in the body. This how they are able to divide and create new cells as we develop from
an embryo. But stem cells aren’t only in embryos, adults also have stem cells that keep
working as we get older.”
“Really?”
“Really. For example, our skin cells are dying and being replaced every day. There
are stem cells in our skin that divide and produce new cells that turn into skin cells. This
allows the skin to keep growing and protecting our bodies, even if some of the cells die or get
damaged.”
“In class we learned that our blood cells only live for a little while and have to be
replaced all the time. Are we able to do this because of stem cells too?”
“Yes, I think you’ve got it. Blood cells only live for about four months and our blood
cells are dying by the billions every day. These cells have to be replaced to make sure that we
have enough blood cells left to live. Actually, if you think about it, in four months every
blood cell in your body right now will be gone. This is possible because we have stem cells
3
in our bone marrow that are able to create enormous numbers of blood cells that replace the
ones that die. In fact, lots of our organs have cells that are dying and being replaced twentyfour hours a day. Stem cells allow us to create the specialized cells that we need to replace
dying cells by dividing and then turning into more specialized cells like those in the blood or
on our skin.”
“Wow. I didn’t realize that stem cells could do so many things. Does this mean that
if a scientist has a stem cell, he can make enough cells to replace any part of our bodies? That
would be really cool, and I bet it would help a lot of people.”
Note to Teachers: This is another good time to stop and highlight examples of the
types of treatments being developed using stem cells. You can ask your students to
discuss whether or not they would undergo a stem cell therapy and why. You can also
ask students to discuss whether it is acceptable to use stem cells in life saving, life
improving, or cosmetic/performance enhancing therapies. Is it more acceptable to use
stem cells in one case than in another? Does it depend on the source of the stem cell
(see the provided Ethics and Stem Cell primers for a description of various stem cell
sources)? You can ask your students to answer these same questions again after
completion of the module to see how their opinions have changed and why.
“That would be really cool, but it’s a lot more complicated than that. Scientists have
to treat stem cells using very complex methods just to get them to divide and change into the
type of cells they want. It has taken many years just to figure out how to collect them and
prove that they can do all of these things. Scientists are only just now learning how to use
them as treatments for people and there are a lot of questions that still have to be answered.”
Peggy, now with a better understanding of what an embryonic stem cell is and where
they come from asks Joe, “Wait, do scientists have to destroy the embryos to get stem cells
out?”
“Usually,” says Joe.
“Isn’t this the same thing as destroying a life? An embryo is the beginning of what
eventually becomes a living animal or person, right? If they destroy it, it can never go on to
become a living animal or person. I know that the research is meant to help patients, and it
sounds like it really works, but is it right to destroy life?”
Note to Teachers: This is a potential “red-flag” issue. The debate over the use of stem
cells is driven by many views and opinions. Students should be encouraged to speak
with their parents, siblings, teachers, and/or religious leaders, etc. to help them form
their own opinions about the topics of “when life begins”. Teachers are encouraged to
refer to the provided Ethics and Stem Cell Primers for more information on how to
approach this question with students. Also, if you feel that a discussion of the subject
of embryonic stem cells is inappropriate for your class, there are a number of other
types of stem cells that may be examined instead of embryonic stem cells. Information
on these cell types may be found in the Ethics and Stem Cell Primers that accompany
this material.)
“I guess I hadn’t really thought about that too much. I was just focusing on how
much good these cells might be able to do for people.”
“It sounds like they might be able to help a lot of people. But, couldn’t an embryo
become a person? Aren’t there any alternatives?”
“Actually, now that you mention it, there are a number of alternative sources of stem
cells. But each one has its own scientific and ethical questions that must be answered before
they can be used to develop a treatment.”
4
Note to Teachers: This case raises a number of questions about stem cells, their
sources, and how they are used. You should choose which of these questions is most
appropriate for your class to examine.
Some suggestions:
Discuss both the scientific and ethical considerations involved with the use of multiple
types of stem cell (see the provided Ethics and Stem Cell primers for more
information regarding the different types of stem cell, their sources, and ethical and
scientific considerations). Have students split into groups and have each one present
the considerations associated with one of the types of stem cell.
Ask students to identify the ethical dilemmas and the types of moral and ethical
reasoning associated with each type of stem cell.
Ask students to create lists of the “Pros” and “Cons” associated with each type of cell.
Ask students to use the line drawing techniques presented in “The Use of Animals for
Educational and Research Purposes: A Case Study for Middle School Students” to
organize and analyze their thoughts about each cell type (see the Harris text for a
more in-depth description of the line drawing technique).
Ask students to discuss how their opinions about the use of stem cells changed
following a discussion of the ethical and scientific considerations associated with their
use.
Ask students for examples of how they think stem cells could be used to help people in
a way that they think is ethically acceptable.
5