Download stem cell ethics: an important consideration in tissue engineering

Budny 4:00
R09
STEM CELL ETHICS: AN IMPORTANT CONSIDERATION IN TISSUE
ENGINEERING ADVANCEMENTS
Andrew Sassani ([email protected])
INTRODUCTION: THE ETHICAL DILEMA
OF TISSUE ENGINEERING:
Tissue engineering is a relatively new concentration in the
medical field that focuses on all aspects of tissue growth and
regeneration [1].The field is not limited to tissues though;
many engineers focus on the development of organs via stem
cells and biological scaffolds [2]. The results of tissue
engineering can be helpful in many applications in the
biomedical field. Such applications include surgical
replacement and testing of new drugs [3]. The practical uses
of tissue engineering are numerous and more are bound to be
discovered with continual research.
Working as a tissue engineer, I have been given a new
project. Doctors at University Pittsburgh Medical Center
(UPMC) need an engineered bladder for a patient with
bladder cancer. The patient doesn’t have an immediate threat
of dying, but is experiencing discomfort from treatment. Also,
the patient has been battling cancer for almost a year and has
exhausted all other forms of treatment with no positive
results; this is his last hope for survival.
As project leader, I will be responsible for various steps in
the process of developing tissues including ordering supplies
and equipment. I will have to face an ethical dilemma over the
stem cells needed to be ordered: Should I order stem cells
from a certain company that harvests stem cells through the
destruction of embryos? Recently, researchers have
developed a method to create stem cells from patient skin cells
(the process will be described later). Or should I find stem
cells that have been formed skin cells despite their low
availability, possibly delay the project and inadvertently
discomfort the patient? As the lead engineer, I must consider
both sides of the debate and make my own decision on how
to act. By reflecting on personal values and engineering codes
of conduct, I must make a decision that will greatly impact
this project.
THE BASICS: HOW TISSUES ARE
DEVELOPED
The process of engineering a tissue/organ is a relatively
standardized process. For most laboratories, engineers start
with stem cells that can be obtained from multiple sources.
Stem cells have the ability to form mainly any type of cell in
the human body (heart, liver, nervous, etc.). Engineers
manipulate these cells to form the desired cell of the
tissue/organ they are developing. However, developing
organs is not as easy as letting cells divide in the lab. Cells
rely on interaction with neighboring cells for complete
University of Pittsburgh Swanson School of Engineering
2013-10-29
function. As a solution to this problem, engineers have
developed extremely small biological scaffolds that allow
physiological connection between cells [4]. Blood vessels are
also grown with extreme accuracy to encompass every cell in
the organ [3]. Without this precision, tissue cells could not
function, ultimately making the organ useless. After
development, these organs can have a multitude of uses.
USES FOR ENGINEERED TISSUES
Surgical Replacement
Tissues are the building blocks of all organs in the human
body. Therefore, when a large tissue or entire organ becomes
damaged enough, the organ can lose all function and
eventually die. On June 9, 2011, doctors had implanted a labgrown trachea into a patient that had been battling cancer for
almost a year. An artificial trachea mold, resembling the
patient’s trachea, was created and then covered in stem cells
from the patient. The stem cells were manipulated in the lab
so they could grow into the appropriate cells for the trachea.
Once the trachea was covered in cells, it was implanted into
the patient; the surgery was successful. The total time for an
organ to be developed using this process takes about 10-12
days [5]. The patient I am working for will undergo a similar
surgery. Knowing that he has been fighting cancer for so long,
I do not want to delay the project by ordering ethically derived
stem cells, but I cannot simply ignore the rights of the embryo.
This is another factor that must go into my final decision.
ETHICS OF TISSUE ENGINEERING
Clearly, the work of tissue engineers has led to
exponential advances over the past decade, but what sacrifices
should be made in the name of progress? How far should we
continue with medical development before we consider our
knowledge too great? These are key questions that engineers
and scientists must face in the development of tissues. The
main issue that affects the development of tissues is the use of
stem cells and how they are obtained.
The popular method for harvesting the stem cells is
extraction from a fertilized embryo. A fertilized egg cell can
contain up to 250 stem cells five days after conception. These
cells can divide and form more even after they are extracted.
The stem cells are vital in a developing embryo because they
have the ability to form any cell in the body. Therefore, upon
extraction, the embryo will die and the possibility of creating
a child with that cell is impossible. Although one life is taken,
should it be deemed paramount despite the enormous benefits
of developing tissues? That is, are the needs of many more
Andrew Sassani
important than those of an individual? It surely seems
tempting to agree with this tenet, but many, including myself
find this unethical. The main driving force behind this
argument is the possibility of life the embryo possessed. The
central reason the embryo was fertilized was to bring a new
life into this world, so it rightly seems researchers are not
entitled to take that gift away [6].
Another ethical argument that arises is about the “moral
status” of the embryo. The moral status mainly refers to the
status of “personhood” so to speak. Proponents of stem cell
research claim that the embryo has no moral status because it
has no properties of a human (emotions, physical properties,
etc.). Based on that theory, they are correct and the embryo
should be utilized to help someone how actually is a living
human being. Those with opposing views claim that trying to
pinpoint an exact point of “personhood” is only an inaccurate
guess. Development of an embryo into the final stage of an
infant is a continual process, so the question of when life
begins is something we cannot fully answer. Also, it should
not matter because life is supposed to develop fully and
should not be abruptly ended [7].
Looking at the moral status from a scientific standpoint
can bring up a new viewpoint. The genetic makeup of the
embryo clearly identifies it as a human being. Although the
fertilized egg does not have the ability to think or feel (the
qualities of “personhood”), it is still technically a human
being. Therefore, this human being, along with other human
beings, is granted basic human rights for living, one of the
rights being the right to live [8]. The decision I make as an
engineer must be based on the debate issues that arise over
stem cells. However, much of the ethical considerations
should be based on public opinions of the issue. As an
engineer in charge of making the decision, I must also look at
professional engineering ethics, biomedical engineering
ethics, public opinions and personal values including my
religion.
embryo will die which would be a direct violation of this
cannon.
Another tenet from the Professional Engineering Code of
Ethics states, “Engineers shall at all times strive to serve the
public interest” [9]. If the engineers should act in the public
interest, do most people approve of stem cell research? The
answer is yes. According to one survey, 68% of the
population approves of embryonic stem cell research [10].
Therefore, in the public’s interest, it seems that the utilization
of embryos for their stem cells is acceptable and should be
done. However, 68% is not exactly an “overwhelming”
majority of the population. The Professional Engineering
Code of Ethics seems too general and vague to draw a
complete conclusion on how to act in this situation.
The Biomedical Engineering Society has their own code
of ethics developed to center around their unique medical
work. Although no specific canons address the controversy
over stem cells, a few can be interpreted to help make a
decision for the scenario. Canon 4 states, “[Biomedical
Engineers shall] Consider the larger consequences of their
work in regard to cost, availability, and delivery of health
care”. To comply with this ethical statement, before I decide
where to order the stem cells and ultimately consider the
consequences. Should I be content with knowing an embryo
was destroyed and receive stem cells on time and continue
with the project? Or should I risk a delay in progress just to
get ethically formed stem cells?
Another canon directly related to research states,
“[Biomedical Engineers in research shall] Comply fully with
legal, ethical, institutional, governmental, and other
applicable research guidelines, respecting the rights of and
exercising the responsibilities to colleagues, human and
animal subjects, and the scientific and general public”. I must
respect human test subjects which includes the embryo itself.
So even if it delays the project, it might be more beneficial to
ethically acquire the necessary stem cells for the project to act
in accordance with this cannon [11].
PUBLIC RECEPTION OF STEM CELLS
AND ETHICS
Religious Views
Despite many outside deciding factors, much of influence
on a decision will come from internal values and morals.
Being a practicing Catholic, a considerable portion of
decision I make will based on religious teaching. Catholics
oppose stem cell research because they feel it is immoral to
destroy an innocent embryo that would have formed into an
actual person. Some Catholic bishops claim that embryo
research will lead to a “domino-effect” where we will begin
to test on living humans because we have crossed a “moral
line”. They claim that stopping testing on embryos will deter
future testing on other subjects [12]. Although I do not
necessarily agree with the domino-effect philosophy, I
understand the moral objection to destruction of embryos.
Many Catholic officials do not completely disregard the
importance of stem cells though. In fact, there is much
attention given by Catholics to ethically harvested stem cells.
Professional Views
Engineers are held to high standards which are listed in
the Professional Engineering Code of Ethics. This code tends
to be more general guidelines because most engineering
disciplines have their own codes unique to their profession;
however, some canons from the professional code can be
applicable to this situation. Cannon II.1 states that, “Engineers
shall hold paramount the safety, health, and welfare of the
public” [9]. This tenet can justify both sides of the argument.
If engineers are to hold the health and welfare of the public at
upmost importance, then it seems that stem cells should
harvested to develop tissues to help the public in need.
However, when harvesting embryonic stem cells, the human
2
Andrew Sassani
In fact, in 2005, Catholics in South Korea raised $10 million
into advancing adult stem cell research [13]. However, adult
stem cells are not as versatile as embryonic stem cells because
they can only form certain cells based on where they were
found. For example, bone marrow is responsible for large
amounts of blood and blood cell production. Many stem cells
can be harvested from marrow, but they would only be able
to form blood related cells. Since I am trying to engineer a
new bladder, I would need to find stem cells from the patient’s
bladder [10]. It isn’t the most efficient way of harvesting stem
cells, but at least the Catholic Church does not completely
ignore the necessity of stem cells in many medical
procedures.
FIGURE 1 [14]
Process of Developing Stem Cells from Skin Cells
ETHICAL HARVESTING OF STEM CELLS
Researchers at Oregon Health and Science University
have developed a method that uses human skin cells and
unfertilized egg cells to develop stem cells. The process
begins by obtaining skin cells from the patient and an
unfertilized egg from a donor. The DNA is removed from the
egg and the skin is inserted into the egg cell membrane. The
researchers then initiate a series of chemical reactions that
allow the cells to fuse. When the cells fuse, the combined cell
is basically identical to an embryo. The formed embryo can
exhibit all the properties of a fertilized egg too, therefore, it
can form useable stem cells. A diagram that illustrates the
process can be seen to the right. The main attraction to
forming stem cells this way is the fact that unfertilized eggs
are used. Without a fertilized egg, no embryo (an embryo is a
fertilized egg) is destroyed, and therefore there is no debate if
a human being was murdered or not [9].
The diagram above outlines the process of how researchers
at Oregon Health & Science University grew stem cells from
skin cells and unfertilized embryos [14].
CONCLUSION: THE DECISION NEEDS TO
BE MADE
Approaching the final decision, there are many
considerations I must keep in mind. The patient and the
embryo are the two entities that will be affected by my
decision. I cannot simply place the importance of one over the
other. To help make the decision, I kept in mind the pros and
cons of each debatable topic on stem cells, the professional
ethics I work by and the personal values that define me. I feel
that stem cells created from skin cells are the best way to solve
the ethical dilemma. They might not be as readily available as
embryonic stem cells, but they can be found and used for this
project to produce desired results. Once they are received by
my lab, coworkers and I will put the project at top priority and
work past normal hours to complete the project on time and
3
Andrew Sassani
[12] N. O’Brien. (2013). “Embryonic stem-cell research
immoral, unnecessary, bishops say.” Stem-cell Research and
the
Catholic
Church.
(Online
Article).
http://www.americancatholic.org/News/StemCell/
[13] (2013). “Catholic Support for Ethically Acceptable Stem
Cell Research.” Stem Cell Research. (Website).
http://www.usccb.org/issues-and-action/human-life-anddignity/stem-cell-research/catholic-support-for-ethicallyacceptable-stem-cell-research.cfm
[14] J. Koebler. (2013). “Scientists Convert Human Skin
Cells Into Embryonic Stem Cells.” News. (Online Article).
http://www.usnews.com/news/articles/2013/05/15/scientistsconvert-human-skin-cells-into-embryonic-stem-cells
[15] “Presidential commission for the Study of Bioethical
Issues.” Presidential commission for the Study of Bioethical
Issues. (Website). http://www.bioethics.gov/
ultimately minimize the discomfort by the patient. I believe
that issues engineers face should be solved through the most
ethical and efficient manner possible. President Barack
Obama once stated, “As our nation invests in science and
innovation and pursues advances in biomedical research and
health care, it's imperative that we do so in a responsible
manner” [15]. In accordance with presidential advice, I feel
this solution has provided effective medical care that is done
in “a responsible matter” yielding an optimal solution for an
ethical engineering dilemma.
REFERENCES
[1] A. Mikos, P. Johnson. (2012). “Overview.” Tissue
Engineering, Parts A,B, & C. (Online Journal).
http://www.liebertpub.com/overview/tissue-engineeringparts-a-b-and-c/595/
[2] R. Yang, W. Gao. (2013). “Introduction.” Generation of
functional organs from stem cells. (Online Article).
http://www.cellregenerationjournal.com/content/2/1/1
[3] A. Trafton. (2012) “Tissue Engineering: Growing new
organs, and more.” MIT news. (Online Article).
http://web.mit.edu/newsoffice/2012/engineering-healthtissue-engineering-growing-organs-1214.html
[4] J. Lannutti, D. Reneker, T. Ma, D. Tomasko, D. Farson.
(2007). “Abstract.” Electrospinning for tissue engineering
scaffolds.
(Online
Article).
http://www.sciencedirect.com/science/article/pii/S09284931
06001421
[5] M. Park. (2011). “Lab-made organ implanted for first
time.”
CNN
Health.
(Online
Article).
http://www.cnn.com/2011/HEALTH/07/07/trachea.transplan
t/index.html
[6] A. Siegel. (2013). “Ethics of Stem Cell Research.”
Stanford Encyclopedia of Philosophy. (Online Encyclopedia).
http://plato.stanford.edu/entries/stem-cells/
[7] K. Hug. (2011). “The ethical dilemma.” Embryonic stem
cell research: an ethical dilemma. (Online Article).
http://www.eurostemcell.org/factsheet/embryonic-stem-cellresearch-ethical-dilemma
[8] R. Doerflinger. (2010). “Old and ethics in the stem cell
debate.” American Society of Law, Medicine & Ethics.
(Online
Article).
http://go.galegroup.com/ps/i.do?action=interpret&id=GALE
%7CA231407923&v=2.1&u=upitt_main&it=r&p=LT&sw=
w&authCount=1
[9] (2013). “NSPE Code of Ethics for Engineers.” Ethics.
(Website).
http://www.nspe.org/Ethics/CodeofEthics/index.html
[10] “Stem Cell Facts.” Americans for Cures: Stem Cell
Facts.
(Website).
http://www.americansforcures.org/article.php?uid=1000
[11] (2004). “Biomedical Engineering Society Code of
Ethics.” 2004 Approved Code of Ethics. (Online Document).
http://bmes.org/files/2004%20Approved%20%20Code%20o
f%20Ethics(2).pdf
ACKNOWLEDGEMENTS
I wish to commend the library for providing the useful
search engine to find compelling articles about stem cell
ethics. In addition, I would like to recognize Cody Fannin,
Andrew Sivaprakasam and Henry Phalen for proofreading my
essay. I would also like to thank Daxton Scholl for providing
help with formatting.
4
Andrew Sassani
5