Stem cells have caused controversy in abundance since the first embryonic cell line was developed in 1998 by James Thomson. One of the main reasons for this comes down to as single word - potential. It is known that embryonic stem cells have the potential to differentiate into almost any cell of the human body and it is believed because of this that they have the potential to take the field of medicine and developmental biology to unprecedented heights. In this dissertation the potential of stem cells both embryonic and adult will be discussed and the issues raised by each contemplated. When thinking about the issues there are several views that people may perceive, these are; the ethics in using stem cells, the social views and also the political policies and issues surrounding their use for medical research. It has even been said that no area of science before has been so deeply interwoven with ethical concern (Christopher Thomas Scott 2006). By looking at how currently stem cells are being used will give an interesting insight into how scientists are likely to want to proceed with research on stem cells and the prospects they have for possible results they will gain from this. Alongside this the future of stem cell research is another important factor to consider as whether or not peoples issues and negative views of using stem cells will be outweighed by the potential they have to cure and solve many medical problems and hence answer the title question.
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When debating a scientific issue it is crucial to first understand the central topic in relative detail. That is why firstly and foremost the science behind stem cells will be addressed in the amount of detail that is necessary to allow valid judgments and an informed discussion to be carried out.
The Science of Stem Cells
There are countless definitions of what stem cells are that can found on the internet and in many textbooks. The most important aspects of stem cells to understand are the roles they play in human development and they mechanism in which they create new and different cells. The word “stem” is a vital clue into the main role all forms of stem cells have, this is because stem cells put simply produce many more cells that originate from this “stem” cell. However it is not quite as simple as this as mentioned there are different types all defined by their potency; a word that will be used in great quantity throughout this dissertation. The two common characteristics that all types of stem cells have are the capability to divide and to differentiate into one or more specialised cell types (Robert J. Brooker 2009).
By describing the types of stem cells in parallel with their formation in human development it also allows us to look at what might be found controversial when cultivating and experimenting with these cells. The story begins when a sperm fertilises an egg, creating a single cell with the two gametes fusion of genetic information forming a zygote. This has the potential to form an entire organism making its potential total or in other words totipotent. In the first few hours this cell divides creating identical totipotent cells, only one of which is needed in the uterus of a woman to continue development. Around four days after the initial fertilisation and in this time several cell cycles of dividing; the totipotent cells begin to take shape into what is known as the blastocyst. This is a hollow sphere surrounded by an outer cell layer, which is encapsulating a cluster of cells (forty to a hundred cells) identified as the inner cell mass. The outer layer has the job of forming the placenta during development and the inner cell mass has the amazing ability to fabricate almost all of the tissues of the human body. These cells are described as pluripotent as can form all cells apart from the placenta and the ability to develop in a woman's uterus. The story however does not end there; these incredible cells still have more to offer as more specialisation is seen to allow for the synthesis of many more different cells with particular functions. This process is known as gastrulation and the pluripotent inner mass cells become either: endoderm, mesoderm or ectoderm tissue, all three being of great importance and current scientific interest in relation to the early embryonic development of humans. These tissues develop into cells that are able to produce several other cells within a certain group, the most understood example, are the blood stem cells, which undertake the essential task of constantly replenishing red blood cells, white blood cells and platelets within the body. This type of stem cell is known as mulitpotent and other examples include skin stem cells and neuronal stem cells. The mechanism by which adult stem cells do this is that when the stem cell divides it produces two daughter cells each with different fates. One of the cells will remain an identical undifferentiated stem cell in order to keep the stem cell population constant, while the other in the case of blood stem cells will differentiate into a red blood cell or any of the other multiple possibilities (Robert J. Brooker 2009). This ingenious mechanism allows a continuous supply of blood cells to be formed to replenish cells with a limited life span. The final type of stem cell that can be catorgorised is the unipotent stem cell which as the name suggests can create only one type of tissue. A good example of this being certain cells in the testis differentiate into only sperm cells.
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Knowing the science behind how stem cells are created in nature is obviously of key importance in this discussion but another main factor that must be comprehended is how research labs obtain and use these cells outside of their natural environment. It was first noticed by Dr. James Thomson that pluripotent stem cells even after a few months in vitro still had the capability and potential to form the three main embryonic germ layers mentioned earlier; endoderm, mesoderm or ectoderm tissue and he went on to say that they “should be useful in human developmental biology, drug discovery, and transplantation medicine.” (Thomson et al. 1998). Little did he know that the word “useful” underrates just how important it is now thought these stem cell lines may prove to be. These cells were obtained from the blastocyst inner cell mass, as mentioned earlier, which contains many pluripotent stem cells. The embryos needed for this to be possible were obtained from an IVF clinic and were embryos that were in excess and therefore had no other use. At the time (1998) this was not illegal and consent was given from the donor couples. A different method at this time was also used to gain embryonic pluripotent stem cells. Dr. John Gearhart method to gain pluripotent stem cells was to isolate them from fetal tissue obtained from terminated pregnancies after informed consent was again obtained from donors. The region of the fetus where cells were taken from was the area from which the testis or ovaries would have developed (Shamblott et al. 1998). Looking at both cultures from these different locations of pluripotent stem cells, little difference could be seen and now due to the illegality of the procedures they undertook in present day America, these stem cell lines are what are used in medical research today in America. More recently another potential technique to harvest pluripotent stem cells has been discovered, called somatic cell nuclear transfer (SCNT). In brief this involves taking a normal animal egg and removing the nucleus, so that all is left are the nutrients and components needed to develop an embryo. The next step is to set up the necessary conditions to allow fusion with this egg cell with a somatic cell. This is mimicking the process of fertilisation mentioned earlier and also therefore is believed to produce a totipotent cell which will go on to form pluripotent cells within the blastocyst and using James Thomson's technique can be collected.
Current benefits from research
One of the main reasons why pluripotent stem cells are so sought after and valuable to medical researchers is that they are able to integrate into almost any human tissue and become a stem cell for this tissue. A word often used for this attribute is plasticity; the ability to incorporate itself with a wide variety of different tissues. The two areas in which medical research is being concentrated due to the belief that is in these areas that stem cells will provide the most benefits for are; in developmental genetics and in regenerative medicine as treatment for many diseases.
A current practice that is being undertaken around the world with very little obligation right now that involves adult stem cells is the process of bone marrow transplantation. This treatment is for certain cancer patients who have had their immune system disrupted by radiation treatment and also other immune related illnesses. The treatment works by simply injecting the patient with bone marrow from a healthy compatible person and the (haematopoietic) stem cells within this will work as they did in the donor and replenish the cells of the immune system by division and differentiation. Other sources of blood stem cells are now also being used for similar treatments as a replacement for bone marrow and these are peripheral blood and umbilical cord stem cells (Urbano-Ispizua 2007).
Along with the aforementioned another current research use that does not involve treatment but instead the better understanding of developmental genetics. Using stem cells and watching how exactly they develop allows scientists to identify the molecular mechanisms involved in this process. It is of particular interest in the factors involved in the cellular decision making process that result in cell specialisation (Michael Ruse Chrsitopher A. Pynes 2003). It is known that genes are involved in producing products such as transcription factors that regulate expression of other important developmental components; nevertheless current research into stem cells is telling us more about the complex mechanisms involved in human development, arguably one of the most appealing scientific discoveries for us as humans.Future areas of development and their potential
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In view of the fact that there are few fully licensed, well developed and practiced current uses of stem cells the main issues lie with the potential uses and exactly what kind of stem cells will be used. To get an understanding of this future in regards to treating diseases here is a table:
Implantation of cells into the brain to treat Parkinson's disease, Alzheimer's and other neurological diseases.
Alongside this treatment for spinal cord injuries, preventing possible paralysis.
Treatment of burn victims and other types of skin disorders such as Xeroderma Pigmentosum.
A damaged liver due to alcohol abuse or disease can be repaired or replaced.
Joints damaged by injury and arthritis can be repaired by new regenerating tissue made by stem cells implanted.
Seriously damaged muscle can be repaired or even replaced is necessary.
Heart attacks and diseases halted before fatal with stem cells used as regenerative medicine source.
Repair of damaged bone or complete replacement with new artificially made bone suitable for host to accept.
As can be seen from this table the variation of use around the body is staggering, showing potential to treat any disease that has some affect on any human tissue. It is because of this ability to integrate into tissue and replicate and replace them that the future of stem cells is providing benefits like none other ever seen. It is no secret that current transplant treatments are hindered immensely by a considerable shortage of donated organs available, overwhelmed by the amount needed . It is this potential of stem cells to be able to regenerate any human tissue that has accumulated most attention from the public and media and the issues of this shall be discussed later.
Before more is spoken about the potential benefits that will be seen, it is key to first state what future development is needed before these aspirations can be reached. As mentioned in the current progress of research, a better understanding of the cellular events that results in cell specialisation must be achieved so that pluripotent stem cells can be induced to become the tissue of choice. Another jump to hurdle is the problem of host rejection in transplantation, due to genetically different tissues. Current research has shown the technique explained earlier of SCNT to be a possible way of overcoming this problem.
A final area where future research could flourish is in the use of pluripotent stem cells for developing drugs and testing them for safety. In the way that cancer cell lines are used for testing on to see if they are susceptible to new drugs developed the same could be done with cell lines of many different tissues made by induced differentiation of pluripotent stem cells into the human tissue needed for testing. This would make the time a drug is made to the time it is tried and tested exceptionally faster as cell lines could be immediately tested on to see if the drug is safe for human use.
The research behind adult and embryonic stem cells
Adult stem cells such as the haematopoietic in bone marrow are mulitpotent and in nature are able to produce several different types of cells to the region of the body it is in. However research by scientists has indicated towards signs of the possibility of artificially inducing an adult stem cell to differentiate into a different type of cell giving them the desirable properties of pluripotent stem cells. This new found flexibility of adult stem cells however as only been seen so far in experiments on animals and applies only to a few tissue types found so far (Michael Ruse Chrsitopher A. Pynes 2003). Work is currently being done to induce human somatic cells to become pluripotent cells known as iPS, which are remarkably similar to those pluripotent stem cells from an embryo. It was found that expression of four transcription factors proved to be a effective method to induce reprogramming of somatic cells to a pluripotent state (Shi 2009). So far experiments on rats has shown that iPS cells have improved symptoms of Parkinson's (Wernig et al. 2008) and also on mice the treatment worked with mice suffering from sickle cell anaemia (Hanna et al. 2007). The creation of stem cells from human adult skin cells was first reported in 2007 by Japanese and US researchers. The technique that was developed involved using viruses to insert four genes into the cells which prompt the switching on and off of other genes and cause the cells to revert to stem cells (BBC NEWS 2009a). This was a lengthy process with minimal positive results but recently in 2009 the process has been remarkably improved with the use of chemicals creating a safer, more efficient way or reprogramming cells to pluripotency (Lin et al. 2009).
Now that there is a clear comprehension of the science of stem cells and alongside that how research is currently being undertaken with them, especially with the breakthrough methods of giving mulitpotent stem cells more potency the issues and views can be discussed.
The Issues and Views
Ethical, Social and Political
For many people it is the overall benefit at the end of a process is what is most important and the label given to this is consequentialists. Those with this view can therefore easily be able to answer the title question by weighing up the benefits and comparing them to any negatives they personally feel with stem cell research.
One question that could be considered the fundamental question that many ask on the ethics of researching with embryonic stem cells is whether or not this research is a form of abortion? (Ted Peter 2007). In relation to this the question that is important to answer for many is when an embryo can be judged to be a life? The answer from the Vatican on behalf of the Catholics views is that it is indeed a form of abortion which they are against on so therefore strongly oppose research with embryonic stem cells. In fact Pope John Paul II was quoted as saying “Stem cell scientists promote the culture of death”. This slightly extreme view is shared also by American evangelicals and orthodox Christians. The reason behind this view is the belief that the blastocyst is a potential human life that is being destroyed. More specifically Catholics believe that when the sperm and egg unite, alongside this god has created an immortal spiritual soul for the early embryo and with this immortal soul a life has been created and thus must be protected from scientists. With this is mind it is clear to see that the views of this religion will stand firm against the use of stem cells. The ethics concerned here by these religions takes the precedence of the embryo's life over what potential life saving qualities it could provide for an adult or child. Of course views against this view come from many scientists and doctors who often debate that why can't the thousands of discarded and spare embryo's from IVF clinics be used? It is estimated that 400,000 to 500,000 embryo's sitting in the freezers of IVF clinics will stay there until they deteriorate (Ted Peter 2007). It is often the view of the head figures in the clinics holding these many embryos that they should be allowed to donate them to scientists for the chance of them being able to be used to help develop the progression of better medicine. It seems this view is held my many politicians also; however a key point to make is that many religions especially Roman Catholics did not give their approval of IVF treatment and storage of embryos. Another extreme view stated by Richard Doerflinger on behalf of Catholic Bishops was that “Intentional destruction of innocent human life at any stage is inherently evil, and no good consequence can mitigate that evil.” (Richard Doerflinger 2001). A scientists view would usually not involve the stage of soul giving (ensoulment) by God but would argue the point that a pluripotent cell taken from a blastocyst to be researched on, has itself no ability to become a individual life when placed in a female uterus, unlike the totipotent cell does, therefore if what is being used cannot develop into a life then surely no life is being destroyed. Of course this view does not take into consideration God and so is disregarded by the religions mentioned earlier.
The next issue to be addresses can be considered a more social one and revolves around the question; are scientists playing God by using genetics and the manipulation of it to get a result good or bad? In regards to this issue my personal opinion would be to say that from looking at history and the successive development of medicine and in fact all technology, the past evidence shows us that scientists have only ever endeavoured their research along the path of to discover the unknown in an attempt to be able to achieve tasks to benefit us as a human race. Arguments against this could clearly come from the fact that scientists have helped develop the most horrific of weapons to kill humans. However whether or not they were forced at the time, must be addressed alongside the point of whether at the time they thought they were on the side of good and justice and by creating this weapon the greater good would be achieved. This view is shared by Christopher Thomas Scott who says “The steady march of humankind's medical discoveries has been overwhelmingly used for good.” (Christopher Thomas Scott 2006).
Those who agree with this statement say that scientist's experiments are unnatural in that they are changing our origin, more religious opinions talk of God not willing his/her creations to be tampered with in this way, alongside general naturalists and social activists who believe that scientists cannot be controlled and are reckless in their path to discovery.
The view against this would immediately argue that this “unwarranted” question is born out of fear. It is well known that human nature is to fear that of which is unfamiliar and in some respects completely new. Therefore some scientists have come out to say that the scientific community should allow their research into stem cells be better documented and not in a complexity that will baffle the general public. “Scientists, having made their research inaccessible to the layperson, must shoulder some of the blame for the confusion.” (Ann A. Kiessling, Scott Anderson 2003). The focal argument of the social activists and nature protectionists is that with further study into genetics as a whole, not just stem cell research, we are beginning to step down a slippery slope from which there is no return. This was also voiced by bishops of the Orthodox Church in America who said that this slippery slope is dangerous and may not be one that can be climbed out of, leading to a tragic devaluation of human life. Another statement along this line of thinking was from one of George Bush's government members Charles Krauthammer who stated a slightly extreme view that “we will go from stem cells to embryo farms to factories with fetuses hanging (metaphorically) on meat hooks waiting to be cut open and used by the already born.” (Leon R. Kass 2002). Alongside this nature protectionists also argue that even in the case of stem cells being deemed ethically okay, the overall spread that biotechnology advances and the pursuit for them cannot be sufficiently anticipated and that human desire for advancement of themselves will go passed just medicine but into unnecessary cosmetic enhancement and so is not socially okay (Ted Peter 2007). It is interesting to see that with this argument targets both embryonic and adult stem cells unlike the embryo life argument before which only applies to embryonic stem cells.
However the view of many, including most predominantly scientists but also many ethics committee's, disagree with this extreme view and that this protectiveness toward mother nature is due to a vague fear that modernity is moving too quickly (Ted Peter 2007). Similar to the issue on when is an embryo a life there are many views that are based on peoples beliefs and opinions, because of this changing the mind of these people is an almost impossible task especially in the case of religion. Yet in a more social view people who are simply unsure about stem cells and the roles scientists play today in genetics, educating them may make the fear and opposition disappear.
The final issue to cover is the role politics plays in the debate of using stem cells in medical research. The reason why politics is such a big issue is because many research labs depend heavily on the funding from government to enable them to carry out experiments. It is also important for another reason, this being even more so relevant in research on stem cells, and that is the laws put in place and guidelines made for any this type of research. A good example of its influence over medical research is in America. President George Bush in 2001 after much debate allowed research on a number of already existing embryonic stem cells lines; this enabled American scientists to try to catch up with European scientists who under different laws were already ahead in medical research regarding stem cells. It is not until now President Barack Obama has come into power that restrictions have been eased further on their use and in 2009 thirteen more embryonic stem cell lines have been allocated for use. The new stem cell policy that allows the use of excess embryos from IVF clinics could see 69 more added to this number, thus showing how politics is crucial with regards to allowing medical research to flourish and thrive (BBC NEWS 2009b). It is also interesting to see how the policies are affected by a countries religious views and how this affects research on embryonic stem cells. As mentioned Catholics are highly against research and therefore countries predominantly of this religion generally have laws banning research. Whereas the Muslim view is that ensoulment and life is 120 days after fertilisation and so research in countries such as Iran is underway without political restrictions. Alongside this is the commercial benefit of stem cell research seen by countries such as in Singapore, allowing again for embryos to be harvested for their stem cells. A final generalisation that can be made is that if a country is more liberal, research is allowed more often than if a country is mainly conservative (Knowles 2004). Nevertheless it is imperative to remember that these are generalisations and that opinions change regularly over time, for example the Catholic countries of France and Spain have recently changed their political guidelines and are beginning to allow research on human embryos (Michael Ruse Chrsitopher A. Pynes 2003).
With the issues and the views being seen it is now possible to discuss the question of whether the potential benefits are worthwhile. Of course the answer will be different for many and I will pose my opinion backed up by the evidence and deductions I have made from presenting the two sides of each issue. The issues raised are dependent on the type of stem cell being used in medical research. The science of these different types is now known and the difference in the potential of embryonic stem cells compared to that of adult stem cells is critical. The use of adult stem cells has almost no objections and this is why in the issues section is barely mentioned. The real controversy comes from the use of embryonic stem cells which are heavily opposed by many different groups of people as seen for many different reasons. This is unfortunate as the science shows that these are the cells that have the real potential and are desired by scientists due to their ability to differentiate into most cells, a trait that would be revolutionary in regenerative medicine. Recently though a breakthrough has occurred and scientists are starting to develop techniques to induce adult stem cells to become more potent and differentiate into a wider variety of cells as mentioned under the medical research section. If success along this road continues it could soon see the stem cell debate come to an unexpected early end as there are no real obligations to the technique of inducing normal adult cells to become pluripotent. “Reprogramming human somatic cells into induced pluripotent stem (iPS) cells without the need of embryos or eggs will solve the technical and ethical problems” (Shi 2009). This view is held by many scientists and is the reason why dedicated research is being undergone in achieving success down this future area of development.
Along with the aforementioned it has come to my attention from researching and reading many reviews on this debate that the course of action that always seems to take place at some point is the eventual need of the scientist to find alternatives to be able to research and use these miraculous cells. This point is proven by the extent of research that has gone into trying to coax adult stem cells to become more potent in an attempt to simply not offend the views of others. It can also be seen that in many countries such as America it is a necessity to do this as the opposition from religion and social activists is fierce and unrelenting in its protest due to their strong beliefs that an embryo at any stage is a life being killed. This observation I feel can reflect on many other current issues in medical genetics, showing the constant battle between religion and science that has been seen throughout the decades.
In regards to my opinion on the use of embryonic stem cells I take the stance that the use of them should be allowed as the benefits (if only potential) to medicine and science in general are unquestionably worthy. I believe this because I feel that from looking at the science and forming my own opinion, the stage at which an embryo is a life should be determined by the parents as it is their creation and their beliefs that matter and if they are willing to donate extra embryos in the case of IVF, I think there should be no problem with this. The fact that the law in most countries allows use of these spare embryos backs up this opinion as a general agreed consensus. My opinion on whether scientists are playing God I have already stated in the previous section.
The main points which I have covered are first and foremost that the exciting and rapidly development of iPS means that soon all issues surrounding embryonic stem cells could be irrelevant as pluripotent cells no longer need to be harvested from early embryo's. In the mean time (however long this may be) use with embryonic stem cells is increasing and even though there are many issues surrounding whether it is morally right the view taken by most is a consequentialists one that the potential benefits are worthwhile. This is proven by the fact that advances are being seen in our understanding of them through allowed medical research with them. Another main point that has emerged is the shear extent of benefits the pluripotent stem cell has and how this may one day come into reality with the continued less restricted progression of medical research.
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