Stem Cell research is a highly controversial and emotive subject that is, more often that not, misunderstood, misrepresented and fraught with ‘ifs and buts’. There are fears that science is moving too fast without giving proper consideration to potential impacts and to ethical concerns. The subject is a confusing and complex one that is difficult to grasp and constantly changing. Governments around the world struggle to develop policies and guidelines at the same time as individuals struggle with their conscience and beliefs.
There are two key areas of debate:
The scientific debate; what is proven, what is debatably proven, research results that are received with skepticism.
The ethical/moral debate; some people base their objections on religious beliefs, some on ethical grounds, others believe simply, that changing or ‘messing with’ the human genome is simply not right, against nature and a highly dangerous path to follow. Others harbour concerns about the directions in which stem cell research can be taken.
Significantly much of the debate is held at an emotional level with scientific facts often overlooked or conveniently ignored. So with that in mind lets first look at the issues that are currently facing scientist in the field.
Exciting claims are regularly reported by scientists with their findings published in reputable science journals with all the relevant data and background information, the media, picking up on these stories, repackages the findings for public consumption and dutifully supplies the splash headline:
‘Brain stem cells to cure diabetes’
‘Giant leap for the ’secret of long life’
Unfortunately the fine detail is the thing that is often lost leading to much misconception, once you get to the small print you discover that all is not as it seems. Sentences like ‘hold much promise’, ’seems to suggest’, ‘has the exciting potential to be’, ‘it is reasonable to assume’ abound in reports of advances in genetic engineering and stem cell research.
WHAT ARE SOME OF THE SCIENTIFIC HURDLES STILL TO BE OVERCOME?
As rapidly as the field of stem cell research is developing new questions and problems arise, with each new discovery another set of problems seems to arrive. Scientist really don’t fully understand why embryonic stem cells can proliferate successfully in the laboratory without differentiating but adult stem cells are not so easily controlled or proliferated. As yet there is no reliable and reproducible way to create stem cell lines. For experimentation to continue successfully it is essential that results can be reproduced repeatedly, at present this simply doesn’t happen. Scientists have yet to agree a set of test to confirm that the fundamental properties of a stem cell exists in a set of laboratory stem cells. Even the test that are used are not wholly reliable and accurate.
In actuality scientist don’t really know exactly how the process of stem cell differentiation takes place, whether the stem cell be embryonic or adult. Differentiation occurs when a stem cell becomes a specific cell type, this happens when the stem cell receives signals telling it to start to become a cell. Scientists barely know what those signals are and how they affect the process. Directing the differentiation of stem cells has developed over the years but is still not an wholly exact science. It seems likely the process relies on a series of complex interactions. Controlling the differentiation is proving to be a major difficulty, how to make a stem cell become the exact cell type you want is not so easy and certainly not reliably reproducible in all areas.
Scientist simply don’t know how many different types of adult stem cells exist and where they exist. They also don’t know how adult stem cells come to exist or how they know where to go to do their repair and replacement functions. The question of just how flexible different adult stem cell types are is still unknown. Some scientist claim that adult stem cells can differentiate into many kinds of cells outside of their specialism, others argue that this is a fluke of the laboratory.
One of the major goals for scientists is to develop a way to use stem cells to repair damaged tissue. To do this they require a large amount of cells. Embryonic stem cells are the easiest to proliferate but are not a genetic match for the patient, adult stem cells are a match but are not easy to grow or control in large numbers. The recent announcement from Seoul University is being seen as a major step forward in this area.
There are many other problems that face the scientists; the laboratory process requires the use of some animal products that leave residue, how long a laboratory created cell survives in a human is an unknown. There has been significant progress in the field but there are still many unanswered questions.
THE ETHICAL DEBATE
The biggest problem with the ethical debate is that the potential for stem cell research to produce cures for some of the worlds most deadly and debilitating diseases is pitted against fervently and deeply held moral and faith based beliefs.
The issue that gets the most attention and is often the focus for opponents of stem cell research is the use of embryonic stem cells. This is because during the process of stem cell line creation the embryo is destroyed, opponents argue that this is the taking of human life – murder. Opponents argue that, as every embryo has the potential to become a human being that each and every one is sacrosanct. Proponents argue that even under natural conditions not all embryos go on to form a baby, that unused harvested embryos would anyway be destroyed and that, ultimately the ends justify the means. Many opponents of Embryonic stem cell research put forward compelling arguments for more vigorous experimentation and research into the use of Adult stem cells. They see this as an answer to the dilemma of the potential for disease relief. In reality this debate is quite clear cut, either you believe that embryonic stem cell research is fundamentally wrong because it destroys a potential human or you believe embryonic stem cell research is acceptable because the embryo will never become a human even if it has the potential to do so.
But this argument is merely a very vocal, media fed argument that only scratches at the surface of far deeper and potentially more impactful debates. There are big questions regarding the potential directions in which stem cell research can be taken; designer babies and eugenics, cloning, chimera. What of the rights of the women who donate their eggs for research and just how much attention is being paid to the health risks? What are the potential impacts of research on the future?
CHIMERA
A chimera is an organism constructed out of living parts from more than one biological species. Many scientist see the creation of chimera as a useful tool for the observation of stem cell behaviour.
The Science
The use of chimera is seen as a way to overcome some of the hurdles outlined above. Basically it allows the scientist to test what happens when stem cells are introduced into a patient, without experimenting on humans. For experimentation purposes what happens is that human stem cells are implanted into an animal host, either an animal embryo or an adult animal. Most commonly used are mice and monkeys. Some of the experiments that have been done already involve implanting brain cells and creating mice with entire human immune systems. It is also worth noting that this is not an entirely new idea and that human-animal chimera also exist in the form of animal tissue implanted into humans; pig heart valves are commonly used as replacement organs for people with heart disease. The extent to which the implanted human stem cells affect the host animal is dependent on the stage at which the material is introduced. If the human stem cells are introduced into an early stage animal embryo then they have a much more profound effect because the stem cells of the host are less differentiated. If the stem cells are introduced into an adult animal the effect, in theory is much less profound because much less differentiation is taking place so the stem cells are more of an addition. But just how far should we go with the use of chimera? Where should the boundaries be drawn? When does the ‘yuck’ factor kick in?
The Ethics
The ‘yuck factor’ is the point at which our reaction to a piece of information or something we see makes us squirm. If we see a monkey running around a cage, we’re unlikely to squirm even if we know that a percentage of that monkeys brain is made up of human cells. But what if we saw a sheep with human feet? Although there is no proof that this has happened, it is theoretically possible. In fact there are a lot of theoretically possible outcomes of chimeric experimentation and many of them may not be so evident to the naked eye. It is the mixing of animal and human cells that concerns the ethicists that have bothered to notice this element of stem cell research. For example how human would a monkey with 20% human cells be, is it human or monkey? Some might say that 20% human cells does not make a monkey human but where is the line to be drawn? These are some of the issues that the bioethicists are fighting with.
For more information on the chimera debate a good starting point is The Other Stem-Cell Debate
For a Christian Perspective: The Stuart Little Syndrome
CLONING
There are two basic types of cloning Reproductive cloning and Research cloning. Reproductive cloning means to recreate a genetic duplicate of a human being and in itself raise a great many ethical issues, therefore it is dealt with separately on this site. Research cloning is the use of cloning techniques to create an embryo for research purposes only.
The Science
The technique can be used to produce stem cells for research. The technique used is called Somatic Cell Nuclear Transfer: SCNT, what happens is that nucleus from a body cell is transplant into an egg. Using electricity or chemicals this entity is triggered into producing an embryo. The resulting embryo can then be used to obtain embryonic stem cells. This process is also know as embryo cloning or therapeutic cloning. Some of the uses for this technique include producing patient specific stem cells, the genetic material of the patient is implanted into a donor egg thus producing stem cells that are a genetic match for the patient. This stem cells could then be used for therapeutic cell transplant. Another proposed use is that stem cells could be created with genetic disorders allowing research of that disorder to be carried out. There are however a few scientific problems; the cost of therapeutic patient specific cell production may make it a non-starter or at least only available to the very rich; the very specificness of the cells means that they can only be given to the patient they were grown for, unlike conventional drugs which can be given to almost anyone. Even though recent research has improved the efficiency of cell line production it still takes a lot of time and eggs to produce very few usable lines. Also lets be clear the technique is still only useful for research purposes and there are many hurdles to be overcome before any real human use is possible.
The Ethics
Lets not forget that cloning in itself uses human embryos whether created using the in vitro fertilization method or using donated eggs, so already we have the ethical difficulties previously outlined. But there are yet more ethical problems arising out of cloning cells. There are fears that research cloning will open the door to human cloning. With the proliferation of cloned embryos the chances of a few hundred embryos going astray becomes more possible. One of the major concerns is the treatment of the women who donate their eggs. How informed is the consent they give?
THE DONORS
Whichever method is used to obtain stem cells at some point or other an egg is needed. Adult stem cells are near to impossible to proliferate outside of an egg, embryonic stem cells are taken from an embryo. So a donor is needed; enter the women. Eggs are often donated by women who seek fertility treatment, they give their spare eggs to science. Some women are paid to produce eggs for research. As far as it is know all women give ‘informed’ consent for the eggs to be taken. But there are big questions being asked as to exactly how informed that consent actually is.
The Science
Cloning and stem cell production requires an enormous amount of eggs. Initial attempts at cloning needed 242 eggs to produce a single usable embryonic line, since then that figure has been reduced to 20 eggs for one embryonic line. During a normal cycle a woman produces just one egg so inevitably women are treated with drugs to stimulate multiple egg production. The process requires a two stage drug programme, firstly to shut down the ovaries and then to stimulate them to produce the eggs. A woman treated with drugs to stimulate multiple egg production can produce about 10 eggs.
The Ethics
At its simplest the procedure for egg extraction is painful and invasive. However the drugs used to stimulate multiple egg production can produce serious health risks. Whilst most women suffer only minor symptoms such as headaches or nausea some can develop much serious problems such as severe ovarian hyperstimulation syndrome, which can lead to dangerous fluid buildup, clotting disorders, renal failure, infertility and even death. One drug that is used in the procedure is called Lupron (leuprolide acetate) a drug that is not approved or tested for this purpose, although it is being legally used because it is approved for other purposes. Lupron has caused many problems which have been reported to the US Food and Drug Administration (FDA) including chest pain, nausea, depression, emotional instability, loss of libido (sex drive), amblyopia (dimness of vision), syncope (fainting), asthenia (weakness), asthenia gravis hypophyseogenea (severe weakness due to loss of pituitary function), amnesia (disturbance in memory), hypertension (high arterial blood pressure).
A woman who donates spare eggs from fertility treatment has a clear motive for wanting to undertake such a procedure, she wants a baby. However those choosing to voluntarily donate eggs will have different motivations; possibly they believe they are helping to find ways to cure disease, but how many realise just how far into the future those cures are? Maybe they are doing it for the money, tho’ laws exist preventing excessive payments in some countries, in other poorer countries that money can be more than useful, but how aware are the women of the risks they are taking ?
EUGENICS AND DESIGNER BABIES
There are issues associated with the connections between stem cell research, eugenics and designer babies. It is within the area of stem cell research that information will be found that will enable scientists to pursue eugenics, the betterment of humanity and the ability for parents to choose not only the sex but also physical and character traits of their offspring, designer babies. Because these are such big issues they are covered elsewhere on this site.
