The stem cell issue-2: The ethics

Yesterday, I discussed the science involved in stem cell research. Today I want to discuss the ethics.

The ethical problems associated with stem cell research occur because although the fertilized eggs were not created for the purposes of research but to help infertile couples, since the method of in vitro fertilization for the treatment of infertility has not been perfected, more fertilized eggs are created than can be used to actually generate pregnancies, and the question of what to do with these extra frozen stored embryos is problematic.

If the extra ones are not needed for future implantation in a womb, then the options are to destroy them, preserve them forever, or use them for research. Those favoring stem cell research argue that preserving them forever is not realistic, that they will have to be thrown away eventually, and that using them for research is better than destroying them without any benefit being obtained, even though the resulting blastocyst must be destroyed in order to produce the stem cell lines,

Those opposed to stem cell research (and abortion) have a simple and clear argument: Life begins at the instant when an egg is fertilized, and no human action is permissible thereafter to prevent that egg from being eventually born. So once an egg is fertilized, whether in the uterus or outside, then we have a human life and using a blastocyst for research is effectively destroying life. This is a secular argument, even though many, or even the majority, of those who support it may have religious reasons for their stand, such as the idea that god inserts the soul at the moment of conception when the egg is fertilized. They argue that if such a position requires the preservation of unused embryos indefinitely, then we should do so, however impractical that might be.

Those who support a woman’s right to terminate a pregnancy and/or the use of embryonic stem cells for research have more difficulty in justifying their position because drawing a clear line as to when ‘life’ begins or a clump of cells becomes ‘human’ is hard. One thing they are agreed upon is that a human being is much more than a fertilized egg or a bunch of cells such as a blastocyst. But where does one draw the line?

One line is that until such time as the fetus can exist independently outside the womb, it is not a human being. Right now that time corresponds roughly to the third trimester of the pregnancy. But as technology improves, that is likely to shift to earlier times. Others argue that any organism (human or otherwise) must have some higher level of capacity, such as a brain, before its life becomes worthy of protection from harm. After all, when it comes to question of death, society seems to have decided that when the brain stops functioning one is effectively dead and one no longer needs to take steps to keep the body alive. And as the Terry Schiavo case tragically illustrated, what we mean by a functioning brain is more than just brain stem functions that maintain basic body processes and some reflexes. It means that the part of the brain, such as memory and cognition, that gives us our personality and makes us who we are must be functioning. Once a person has reached the stage of being in what is known as a ‘persistent vegetative state’, that person is considered to be effectively dead.

In this debate, both sides usually ignore the need for consistency across species. Why should only human life be so valued? What makes us superior and worthy of special consideration? If life is precious and life begins with a fertilized egg or with higher brain function, then what about the lives of other species? After all, we kill animals, even though they are fully functioning living things with a level of brain function that we would undoubtedly value if a human had it. We even think nothing of eating them after killing them. Why should we have one standard for humans and another for nonhuman animals?

One can take a speciesist position and simply assert as a given that human beings are superior to others and so we have a right to do what we like to other animal forms while treating human life as sacrosanct. But that is hard to justify on general moral or ethical grounds. There is no clear marker that justifies treating humans as special, unless you throw in ideas such as that humans have a soul and other animals do not. This is an argument based on a particular religious viewpoint and should have no place in determining public policy, which should always be based on secular arguments.

In my opinion, the position taken by ethicists such as Peter Singer is the most consistent moral and ethical one, that does not give humans special privileges. They take a utilitarian position, that what one should seek is the minimization of suffering. Since suffering involves sentience, this requires that an organism must have at least some primitive brain function and the development of a nervous system before it can be said to have the possibility of suffering. So it would be acceptable to destroy any system of cells (whether from a human or non-human animal) as long as it has not yet reached the stage where it has the ability to suffer, or it has passed that stage at the end of life.

Even if we do not achieve the high level of consistency that it requires of us, the utilitarian argument that says that what we should aim for is a net reduction of global suffering seems to me to be a workable ethical principle on which to base decisions like these. Hence it is ethically allowable to use embryonic stem cells from a blastocyst (before the cells themselves have reached the capacity to suffer) in order to do research to reduce the suffering of actual living organisms.

Of course, this raises other potential problems that are sure to come down the road. Is it ethical, for example, to deliberately produce blastocysts purely for the purpose of research, as opposed to using those that are the by-products of infertility treatments? If, for example, one wanted to study the early development of a disease that had a genetic basis, would it be ethical to take an egg and sperm from people who have that disease and create a fertilized egg purely in order to study the early onset of that disease or to develop treatments for it?

These are very tough questions but ones that are going to come at us thick and fast in the near future as science and technology inexorably advance.

POST SCRIPT: God will decide if and when and how the world will end

Two days ago, I suggested that religious people make unreliable allies in the battle to save the environment because of their belief in god’s plan. Right on cue, we have a member of the US Congress during hearings last week on cap-and-trade policies to reduce carbon emissions, quoting the Bible (Genesis 8:21,22 and Matthew 24:31) to support his belief that the future of the Earth is part of god’s plan. Yes, god has our back, based on what he supposedly told Noah after the flood. So don’t worry, burn those fossil fuels because Jesus has it covered!

The stem cell issue-1: The science

The decision by the Obama administration to reverse the Bush-era policy of banning the use of federal funds for stem cell research has created some controversy. The earlier policy had led to some frustration in the scientific community.

Bush’s policy was intended to be a compromise: it banned the use of federal funds for the creation of new embryonic stem-cell lines while allowing scientists to study 21 lines that had already been created. But researchers say those lines aren’t diverse enough and they have been eager to study hundreds of other lines, some of which contain specific genetic mutations for diseases like Parkinson’s. There have been practical challenges as well. The restrictions forced scientists to use different lab equipment for privately funded and government-funded research; some even built entirely separate lab space. One of the most disconcerting aspects, researchers say, has been the negative effect on collaboration, a hallmark of the scientific process. Researchers supported by private money haven’t been able to team up with scientists funded by the government, potentially holding back new insights and advances.

Stem cells are those that have three properties. Unlike most cells like muscle or blood or nerve cells, 91) they are capable of replicating themselves for a long period (making them a valuable source to regenerate the body by replacing cells that die), (2) they are unspecialized, and (3) when they reproduce they can produce either more stem cells or become specialized cells like muscle or nerve or bone (a process known as differentiation). The National Institutes of health has an informative FAQ page on this topic.

The two main kinds of stem cells are the embryonic ones and the non-embryonic ones. The embryonic ones can proliferate for a year or more in the laboratory without differentiating while the non-embryonic ones cannot do so for very long, but the reasons for this difference are not known as yet. The embryonic stem cells are capable of eventually differentiating into any type of specialized cell, and are called pluripotent. Such pluripotent cells are valuable because they can be used to repair tissue in any part of the body as needed. But eventually they need to differentiate into specialized cells in order to perform the functions that those specialized cells carry out in the body. The process by which stem cells differentiate is still not fully understood, but part of it involves interaction with the external environment in which the stem cell finds itself.

Adult stem cells are one form of non-embryonic cells and are found amongst the differentiated cells that make up the tissues of the body, such as the brain and heart and bone marrow, and they are the cells that are used to maintain and repair those tissues by differentiating when needed to produce new tissues. Some adult stem cells seem to have the capacity to differentiate into more than one type of specialized cell though the range is limited, unlike in the case of embryonic stem cells. Such cells are called multipotent.

For example, some multipotent stem cells found in the bone marrow can generate bone, cartilage, fat, and connective tissue. Stem cells taken from umbilical cord blood and the placenta seem to also have multipotent properties and thus in the future it may become routine that a stock of umbilical or placental cells will be taken after every birth and preserved for possible future use. Adult stem cells have some uses but working with them is much more difficult since they are harder to obtain and are less flexible.

To understand the ethical issues involved in using embryonic stem cells, one should be aware that creating embryonic stem cell lines for research requires extraction of cells from the blastocyst. This is the stage reached by a fertilized egg after about three to five days when, after repeated cell division and duplication, there are about 70-100 identical cells in the shape of a hollow ball containing an inner clump of cells. The inner clump becomes the embryo and the outer hollow ball becomes the placenta. When this occurs in the uterus, this stage is reached before this collection of cells gets implanted in the uterus wall. Sometimes implantation does not occur, in which case the pregnancy is spontaneously terminated.

This video explains what stem cells are and how they work.

The embryos from which embryonic stem cells are taken are produced during treatment for infertility when a woman’s egg is taken from her body and fertilized and grown to blastocyst stage in a culture outside the woman’s body. In the very early days after the egg is fertilized and the cell starts splitting and reproducing itself, all the cells are identical. Embryonic stem cells are obtained from that inner clump of cells and thus the blastocyst has to be destroyed in the process. The cells from a single blastocyst can be used to generate millions of embryonic stem cells that can be divided among researchers, and these are the stem cell ‘lines’ that are referred to. The cells in a single line are all genetically identical.

While there are promising new ways of creating embryonic stem cells using adult skin cells (called induced pluripotent stem cells), they have their own ethical issues.

Since tissues created from a person’s stem cells have the same genetic information as the host, the host body will not reject the implanted tissues as a foreign body, thus overcoming one of the biggest hurdles in organ transplants. While the possibility of growing tissues and entire organs for transplant purposes is often publicized as the biggest potential benefit of using stem cells, there are other more immediately realizable potential uses for embryonic stem cells.

One is that it enables the process by which cells differentiate into their specialized forms to be studied. Another is that by creating cells that have a particular disease, say Parkinson’s or Lou Gehrig’s, one can observe under a microscope even the earliest stages of the progression of the disease and thus hope to develop better treatments. Another use is to test the effects of drugs on cells before testing them on a real person. That would enable you to see if they are toxic to a particular individual, creating a level of personalized medicine that we do not currently have.

The potential benefits of embryonic stem cells in research are clear, even though it is very early days yet and there is still a long way to go before we can hope to even begin realizing those benefits. The key question is how to balance the ethical concerns involved in using such cells with the benefits.

This question will be examined in the next post.

POST SCRIPT: The Daily Show on stem cells

The Daily Show With Jon Stewart M – Th 11p / 10c
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Are religious people reliable allies on the environment?

Evolutionary biologist E. O. Wilson gave Case Western Reserve University’s annual Distinguished Lecture on March 3, 2009 in Severance Hall, the magnificent building where the equally magnificent Cleveland Orchestra plays, was packed for the occasion. It seemed to underscore the community’s support for, at least interest in, the theory of evolution.
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