Document Sample
STS Powered By Docstoc
					                         Courtesy of Kevin Yurkerwich. Used with permission.

                                                                                      Waits 1

Should Embryonic Stem Cell Research be Permitted to Continue?

     Over the past few years a debate has been going on over the moral implications of

embryonic stem cell research and the proper funding for that research. When considering

a topic of this importance, it is essential that one take a step back and review its merits as

well as the alternatives, and ask what it is that those promoting it are trying to accomplish.

Is the cure worse than the disease? In the case of embryonic stem cell research, the

answer is yes. Embryonic stem cell research is immoral and should be stopped, as there

are other more ethical alternatives available that are being ignored by scientists that are

solely focused on embryonic stem cell research.

     To begin a discussion of stem cells, it is important to address the basic definitions

surrounding the research in order to understand its significance. The most important

distinction is between totipotent, pluripotent, and multipotent stem cells. Each of these

terms refers to the ability of the stem cell to create different kinds of cells. Totipotent

stem cells are those that can grow into an entire organism (a blastomere is an example).

Pluripotent stem cells aren‟t able to form a whole organism, but can become any cell in

the body. Multipotent stem cells, however, can only become some types of cells,

multipotent stem cells are often called unipotent as they usually only form one type of

cell. Embryonic stem cells are pluripotent cells that are obtained from the inner mass

cells of an embryo. Adult stem cells on the other hand are mostly multipotent,

undifferentiated cells that are found among different differentiated cells of a certain tissue.

Differentiability refers to the cell‟s ability to produce other kinds of cells.
                                                                                    Waits 2

Differentiated cells are those cells that can only produce one particular type of cell, while

undifferentiated cells can produce more than one type of cell.

Before discussing the controversy at hand, it is also important to understand how it is that

embryonic stem cells are formed, and how they differ from adult stem cells. Embryonic

stem cells are obtained by fusing a patient‟s cell with an enucleated egg cell forming an

embryo. The embryo is then allowed to grow for approximately five days until it is

anywhere from a few tens of cells to 150 cells. The stem cells can then be extracted from

the inner mass cells of the embryo, resulting in the destruction of the embryo. The stem

cells are cultured, and they will grow and divide indefinitely creating a “stem cell line” of

offspring sharing its genetic characteristics. Adult stem cells, however, are present in

many different tissues, most notably in bone marrow, and are responsible for the daily

production of certain specialized cells such as red blood cells. These cells are extracted

from the patient, grown in culture and then reinjected into the same patient with no

destructive effects to the tissue or the patient.

The main advantage that embryonic stem cells have over adult stem cells is that the

embryonic cells are totipotent. They have the ability to differentiate into every cell in the

body, thus making them more attractive because their potential is not limited by the kinds

of cells that they can become. Recent evidence proves that some adult stem cells can

transform into several different forms, but no human adult stem cells have been found

that are pluripotent.

     Embryonic stem cells have far fewer problems associated with their use, but the

moral issue surrounding the destruction of the embryo is the heart of the issue. Some

believe that life begins as soon as the embryo is formed and that if the embryo has the
                                                                                     Waits 3

potential to become a human, destruction of that embryo for any reason is killing a

human being. Furthermore, embryonic stem cell research is significantly behind adult

stem cell research and has not yet proven its efficacy, which begs the question: Why

invest in controversial research that isn‟t guaranteed to work as well as a solution that

already exists?

This is one of the major advantages of using adult stem cells: they are already being used

effectively for over one hundred diseases, while embryonic stem cells are still untested.

Adult stem cells also have two other very powerful advantages: they are obtained from

the patient so there are no moral issues surrounding their use, as the stem cells, first, are

obtained with consent from the patient, and, second, the procedure does not harm the


Adult stem cells research is yielding some intriguing results. As mentioned earlier, some

adult stem cells have been found that can transform into several different forms; one

example is bone marrow stem cells which are able to transform into liver, nerve, muscle

and kidney cells depending on what the body needs. Researchers have also extracted stem

cells from skin which are able to differentiate into neurons, smooth muscle cells, and

fat-cells. More surprisingly, some adult stem cells have been discovered in mice which

are claimed to be pluripotent. With time, it may be found that adult stem cells exist in

humans that are pluripotent, thus negating one of the biggest advantages embryonic stem

cells have over adult stem cells.

     Adult stem cell research is not without problems, however. Adult stem cells are

generally multipotent (though exceptions to this have been proven to exist), and can‟t

give rise to all cells. Unlike embryonic stem cells, adult stem cells are often found in
                                                                                       Waits 4

minute quantities which can be difficult to isolate and purify. Also, adult stem cells may

not have the same capacity to multiply as embryonic stem cells. Lastly, due to the length

of time that adult stem cells have been present in the body, there is a higher risk for DNA

abnormalities due to sunlight, toxins, and errors in DNA replication over the course of a

lifetime. These abnormalities could be magnified when the stem cells are cultured and

may not present as “pure” a sample of stem cells as embryonic stem cells would.

Steps have been taken to curb embryonic stem cell research. Most notable is President

Bush‟s Executive Order of 2001 concerning the use of federal funds for the research of

embryonic stem cells. The President halted federal funding for the creation of new

embryonic stem cell lines, and placed stringent criteria on the funding of existing cell

lines. In order to receive federal funding the criteria that must be met include: 1)

informed consent of the donors, 2) the lines must be from excess embryos created solely

for reproductive purposes (In Vitro Fertilization), 3) no financial inducements made to

the donors. Of the 72 embryonic cell lines that meet these criteria, only 22 are available

for distribution due to complications with cryopreservation. In addition, many lines are

contaminated with mouse feeder cells, which may hinder the FDA approval of their use

in humans.

     There are several problems with this policy. The president, and most proponents of

embryonic stem cell research, argue that the extra embryos created during in vitro

fertilization are destroyed, but could be put to good use. The problem with this thought

process is a fundamental rule of ethics: the ends can never justify the means. The

destruction of human embryos is wrong, as it is a human life (or the potential to become a

human being) that is being destroyed; but to benefit from their destruction is also wrong.
                                                                                      Waits 5

The other problem with the policy is the first point of the funding criteria, „informed

consent of the donor.‟ If it is assumed that the embryo is a human life, or the potential to

become a human life, are we saying that a parent can donate a child to science? Where

will this volunteered sacrifice end, and who‟s in charge? This can quickly spiral. Who

knows where it will end? Is it so far fetched to imagine a future ,based on this foundation,

where we can give consent for the termination of the elderly as well? Preventing funding

for the creation of new cell lines was a step in the right direction, but it did not go far

enough in that the President should have denied all embryonic stem-cell-research funding

where the destruction of a human embryo was involved.

Many people disagree with this stance, citing all of the ways that embryonic stem cells

can improve our lives. It is true that they have the potential to help, but few people realize

how many alternatives there are to embryonic stem cells. Perhaps these alternatives are

not being considered because so many are focused on embryonic stem cells, and haven‟t

considered that there could be another option that would work better. Some of these

options include: umbilical cord blood stem cells, adult stem cells, the use of Reversine,

and altered nuclear transfer.

     Blood from the umbilical cord and placenta is a source of adult stem cells. In order

to use them, the umbilical cord is removed and blood is extracted. The blood is then

analyzed for infectious diseases and the tissue type is determined. This blood is frozen

and when it is needed, it is thawed and injected through a vein of the patient. Cord blood

stem cells have been used since 1988 to treat Gunther‟s Disease, Hunter syndrome,

Hurler syndrome, and Acute lymphocytic leukemia as well as many more problems

occurring mostly in children.
                                                                                      Waits 6

                 Adult Stem cells are being used in a number of surprising ways; the more

research that is done, the more is discovered that was never known. Adult stem cells have

been used to treat paralysis due to spinal cord injuries, Parkinson‟s disease and other

illnesses. Injecting adult stem cells into the brains of rats has be successful in treating

cancerous tumors. Adult stem cells have been shown to repair muscle damaged after

heart attacks by injecting bone-marrow stem cells into mice that had heart attacks,

causing 33% improvement in function of the heart, and damaged tissue regrew by 68%.

Researchers were able to harvest stem cells from the brains of cadavers and were then

able to get them to divide into valuable neurons. Scientists at the University of Toronto

were able to form neural stem cells by using skin cells, showing that adult stem cells are

not as unipotent as originally believed. In fact, in time of emergency, multipotent stem

cells in the bone marrow change to become almost any type of cell responding to the

body‟s needs. Finally, adult-derived stem cells are endowed with additional

developmental instructions, which may cause them to be better suited for therapeutic


     Another breakthrough alternative to embryonic stem cells is Reversine, a small

molecule identified by researchers from Scripps Research Institute which causes a cell to

undergo dedifferentiation back to its own precursor cell. This precursor cell has the

potential to become different cell types, and presents a tool for generating an unlimited

supply of precursors which can be converted to other cell types such as bone or cartilage.

     The last, and one of the most promising alternatives is altered nuclear transfer.

Altered nuclear transfer engineers a human egg that generates cells with full potential of

embryonic stem cells without ever forming an actual embryo. This is accomplished by
                                                                                     Waits 7

turning off a gene in the donor DNA before it is fused with the enucleated egg. The gene

that is turned off directs the formation of the trophectoderm, a layer of cells crucial in the

first stages of development. All cells in the mass will eventually die, but scientists can

still harvest embryonic-type stem cells from it. The important part of this process is that

the mass is not an embryo so it won‟t be “killing” it by harvesting the stem cells (though

the mass is destroyed, it is not a human embryo). Some of these steps have been

demonstrated in mice, but the challenge will be silencing the gene and then turning it

back on in the stem cells so they aren‟t flawed. The last hurtle for altered nuclear transfer

will be to gain a consensus that the mass of cells is not a human embryo – we must be

able to distinguish between a damaged embryo and something that can not be considered

an embryo at all. A professor of jurisprudence at Princeton said that in order to be

considered not to be an embryo, it “should not have integrated organization, it must not

have „the self-directed active disposition to become the next mature stage,‟ and crucially,

the genetic alteration must be made „ab initio‟ – or from the beginning – so it cannot be

argued that the procedure merely creates a disabled embryo,” [Cook]. All three of these

criteria are met by altered nuclear transfer.

     These options show that a number of alternatives to embryonic stem cell research

currently exist. Embryonic stem cell research is immoral; it exploits a life that cannot

give its consent. Therefore, all embryonic stem cell research must stop, including

research utilizing those stem cell lines already created. Continuing research on these lines

of cells may open Pandora‟s box. If it has been decided that it is wrong to make new lines,

what happens if a miracle cure in the existing lines? Will we just ignore the fact that it is

wrong and open new lines to exploit the wonder cure? Where will it end?
                                                                                 Waits 8

As Michael Crichton wrote of the scientists in Jurassic Park: they were so caught up in

whether they could that they never stopped to think if they should. There are other

solutions that can benefit humanity without relying on immoral means to do so. We must

acknowledge our responsibility to conduct the exploration into these solutions in an

ethical manner. We must look deeper for a solution that balances the needs of humanity

and the requirements of ethics.

Shared By: