Colin Blakemore on Stem-cell Research
This is part of an interview of Colin Blakemore by Jeremy Stangroom which took place in 2004. The whole interview appears in What Scientists Think, Routledge 2005.
The issue of animal experimentation is not the only area of dispute in the field of medical science. There is also, for example, considerable public debate about the use of stem cells – roughly speaking, cells which have the capacity to differentiate into cells of any type – in medical research. What, I ask Blakemore, is the importance of stem cell research?
‘It’s very easy to slip into hype when answering this question, but even so, I would say that the discovery of stem cells, and of their potential to transform into any tissue type in the body, really offers the possibility of one of the most significant advances in the history of medical treatments,’ he replies. ‘Most importantly, the kinds of diseases which potentially can be treated with stem cell therapy is a whole range of presently incurable diseases which are growing in rate in the population because of ageing. These are the degenerative diseases. The possibility of replacing tissue which no longer functions properly is extremely exciting. The kinds of conditions which might well be treatable, and for which there are already animal models of treatment, include Parkinson’s disease, Alzheimer’s disease, diabetes, heart disease, bone disease, stroke and cancer.’
In May 2004, the world’s first stem cell bank, partly funded by the MRC, was opened in the UK. On its opening, it contained two stem cell lines, developed by teams from Newcastle and London. What’s the idea behind banking different stem cell lines like this?
‘There are actually a number of reasons for banking stem cell lines,’ Blakemore answers. ‘The main one is to provide uniform standards for typing the cells; for understanding their composition and makeup. It is estimated that perhaps as few as one or two hundred different stem cell lines, each with different immunological characteristics, will be enough to provide tissue type matching for virtually every person who needs a transplant. So it’s a bit like matching blood groups, or indeed tissue typing for organ transplants; it is necessary to get the match right, which is the main reason for collecting more than one line.
‘The other reason is that different stem cell lines might have a better capacity to transform into particular kinds of adult tissue. We don’t know enough yet about the basic biology of stem cells to know this for certain, but it is possible that although all stem cells from embryos are derived at a similar stage of development, between 0 and 14 days of age, some of the lines will be better at transforming into say heart or brain than others. So this is a second reason for having more than one line.’
The moral objections to stem cell research tend to be voiced primarily by people who object to the use of embryos in the collection of stem cells. For example, Patrick Cusworth, spokesperson for the anti-abortion charity Life, claimed that the use of embryos in stem cell research ‘reduces human life to little more than a pharmaceutical product’. What does Blakemore make of this kind of argument?
‘Well, I said earlier that we should have a special attitude towards other humans, so crucial to this argument is how we define a person,’ he replies. ‘A pro-Life group will say that a fertilised egg is a human being. I don’t accept this; if any cell which has a full complement of DNA and is capable of transforming into a human being is a person, then every cell in a human body is a person. We now know from Dolly the sheep that if we take the nucleus from an adult somatic cell – a cell from our skin, for example – and put it into a vacant egg, then it can become a human being. Should we therefore be worried about every cell which sloughs off from the surface of our skin? Should we treat each one of those cells as if it were a person? Obviously not. We have to recognise that an embryo, certainly before the nervous system begins to form, is just a bundle of cells.’
People who are opposed to research which uses stem cells taken from embryos also claim that there is no scientific case for the practice; that adult stem cells will do just as well. Is there any truth to this claim?
‘This sounds very like the argument which the animal rights lobby makes about the alternatives to animal experimentation,’ Blakemore replies. ‘My response is to say show me the heart surgery which is going on using adult stem cells. It doesn’t exist. It might be that harvesting adult stem cells will be the right thing to do at some point in the future. One of the great advantages of adult stem cells is that you can do autotransplantation; you can take cells from a patient, let’s say bone marrow stem cells, or neural stem cells from the nose, grow them up so that there are enough of them, and then use them to treat whatever problem the person you took them from is suffering. In this situation, there is no difficulty with tissue typing, it will match perfectly. But we don’t have the expertise at the moment to do this; we would need to know a lot more about stem cells, and this knowledge is going to come from the study of embryonic stem cells. But the hope is that one day we will be able to use adult stem cells.’
What about if a person has an illness which is caused by a genetic mutation? Presumably it won’t be easy to treat something like Huntington’s, for example, with a patient’s own stem cells?
‘It’s true that if a person carries a genetic mutation then it is present in their stem cells; but actually this doesn’t necessarily mean that you couldn’t use their own stems cells in a treatment,’ Blakemore says. ‘Huntington’s disease is a dominant genetic disorder. The symptoms, though, don’t appear until the person is thirty-five or forty years old. So although the gene is carried from birth, it doesn’t express itself until later; the problems accumulate gradually. It is conceivable, therefore, that if you were to derive neural stem cells from someone with Huntington’s disease, and you then transformed them into new nerve cells, that they too would last for many years before the condition showed itself. So there is this possibility.
‘One of the things which should be emphasised about stem cell research is that it is going to provide much greater insight into the nature of disease. It isn’t just a matter of developing new treatments, it is a way to understanding disease. For example, stem cells are helping us to understand the cancer process, because, like cancer cells, stem cells are immortal. Also, our understanding of the normal development of human embryos will be helped by understanding stem cells; we’ll learn about the rules which cause uncommitted cells to transform into committed cells. Finally, we can learn about the nature of certain diseases by studying the stem cells of people who carry genetic defects.’
Does Blakemore have a view about how the various issues and debates surrounding medical research are likely to play out? Is he optimistic about the future?
‘I think it is necessary to learn the lessons of history,’ he replies. ‘I remember that after the first heart transplant there was intense criticism from the church, civil libertarians, medical ethicists and the animal rights lobby. People complained that the original research had been done on pigs; that the procedure was a dangerous experimental technique; and that it was possible that patients were being coerced into undergoing transplants. All the same kinds of arguments that we hear now were being played out then. But people today think that heart transplants are a medical miracle. The public completely accepts the procedure. Social and moral attitudes then are not absolute and fixed; they are influenced by the evidence of benefit. My view is that if we keep the public informed, if we move forward gradually, then, as and when the benefits accrue, the issues will become progressively less contentious. I am actually extremely optimistic about the future of medical research. The investment of the last fifty years in basic biological research is going to deliver in very big ways in terms of human health and the quality of people’s lives.’