Stem Cell Research: Select Committee Report

Part of the debate – in the House of Lords at 6:11 pm on 5th December 2002.

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Photo of Baroness Cox Baroness Cox Conservative 6:11 pm, 5th December 2002

My Lords, I speak with trepidation because this subject has such profound ethical, theological, scientific and clinical implications and because of my respect for members of the committee, for the enormous amount of work they have devoted to the preparation of this report, and to their personal commitment to ethical and scientific integrity. I therefore express my concerns with profound humility. However, I have voiced them previously, and subsequent developments have not allayed them. These include the apparent arrogance of the United Kingdom in going it alone while other European countries and the United States have been constrained by scientific and ethical arguments from going down the path recommended in this report. That point has been very fully made by the noble Lord, Lord Alton.

Furthermore, while great emphasis is laid on the therapeutic potential of embryonic stem cells, it is acknowledged that these cannot have any effective clinical application for many years. However, the progress being made with adult stem cell research suggests that they may have more to offer without the immense ethical or safety problems associated with embryonic stem cells. Everyone wishes to hasten therapeutic developments to alleviate the anguish of illnesses such as Parkinson's disease. As a nurse, I cannot feel anything other than passionately committed to measures to relieve suffering in a whole range of diseases which may be treated by stem cell therapies. However, the question must be asked whether it is prudent to proceed now with a more ethically and clinically problematic route of embryonic stem cells when the option of adult stem cells is generating very positive results and is being used successfully in many parts of the world. Indeed, the United Kingdom is being left behind in this field of research.

The right reverend Prelate the Bishop of Oxford referred to the report's encouragement for adult stem cell research. Encouragement is one thing, funding is another. In the United States, 75 per cent of private funding is going to adult stem cell research organisations, whereas embryonic stem cell research organisations are receiving a very small amount and are struggling to survive. I should therefore like to ask either the Minister or the right reverend Prelate how much funding is currently underpinning the encouragement for adult stem cell research. I should also like to concur with the noble Lord, Lord Tombs, when he expressed his grave concern about the suggestion that the situation should be reviewed towards the end of the decade. The issue is much more urgent than the end of the decade. However, I shall focus on the risks of embryonic stem cells as they seem to receive such inadequate consideration in the report, perhaps because the relevant experts who could present the alternative arguments were under-represented in the witnesses giving evidence.

The report claims that there is no reason to suppose that the risk of tumour formation is higher in embryonic stem cells than in adult stem cells and that cultured embryonic stem cells are unaltered and can be grown and manipulated safely in culture. But these claims are contrary to all the available peer reviewed evidence. I therefore offer some counter arguments which are grounded in reputable scientific research. Time will not permit me to cite the sources but I shall make those available in a fuller paper which I shall place in the Library for anyone to check my claims and arguments.

First, the report does not address the very serious risk of teratoma or teratocarcinoma formation with embryonic stem cells. These are tumours composed of a mixture of various inappropriate tissue types such as bone, cartilage, hair or teeth, which can develop anywhere in the body, for example, in the heart or in the brain.

Tumour formation is not a hypothetical risk but is, or can be described as, an intrinsic property of embryonic stem cells. Indeed, the presence of only a minute number of embryonic stem cells (relative to the numbers implanted in stem cell therapies) is sufficient to generate these tumours. The report also clearly implies that adult stem cells are just as likely to form teratomas, stating that there is

"no reason to believe that (there) is a significantly greater risk for embryonic stem cells than for (adult) stem cells".

But, so far, adult stem cells have not been found to produce these tumours.

Secondly, there are a number of ways that embryonic stem cells and their differentiated progeny could generate cancer, when they are cultured as would occur in the process of multiplying embryonic stem cells for therapies and to an even greater extent in the case of the proposed stem cell bank. The risk is greater still if the embryonic stem cells are obtained from "therapeutic" cloning.

Recently, a form of mutation in embryonic stem cells in culture has been identified which could result in cancer. In this case the cells appear to have the correct number of chromosomes, but they are the wrong chromosomes. There are no copies of a chromosome from one parent but two from the other parent. It is a particularly dangerous form of mutation. The study, which investigated mutations in embryonic stem cells, was reported in the proceedings of the National Academy of Sciences in the United States of America earlier this year. The authors state that the increased risk of tumour formation after (embryonic) stem cell therapy should be viewed with concern. By contrast, they state that this mutation

"is not commonly observed in other normal somatic cells"— this includes adult cells.

Thirdly, the report also claims that cultured embryonic stem cells are unaltered and safe because these cells, at least in the case of mice, can form normal offspring. But the report does not reveal the vast numbers of embryos produced from cultured embryonic stem cells that fail before one succeeds, and the very high percentage that have foetal abnormalities or are born with gross abnormalities or that die at or around the time of birth or shortly after.

The reality is that the experiments described so positively in the report demonstrate clearly that cultured embryonic cells are altered and unsafe, not unaltered and safe. It thus appears to give them a clean bill of health whereas there are numerous ways in which they could cause tumours, including cancers. If this issue is not addressed thoroughly, and if in future years people develop such tumours from embryonic stem cell therapies, they and their relatives will not look kindly on the committee which claimed that embryonic stem cells were unaltered and could be safely cultured despite the fact that there is much evidence to the contrary.

With respect to "therapeutic" cloning, the risks would be even higher because of the very high incidence of severe abnormalities in cloned embryos. If these defective embryonic stem cells were used for "therapeutic" cloning, they would produce defective cells. Unfortunately, in the majority of cases, the abnormalities would not be detectable, as at present in many cases there is no way to tell which are the defective cloned embryos. If such defective cells were used for therapies, they would be likely to cause cancer.

Finally, through ignoring the dangers of embryonic stem cells, and attributing the unique advantages of adult stem cells also to embryonic stem cells, the report commends a procedure that would instantly result in tumour formation if embryonic stem cells were used, despite having received clear warning of those dangers.

Numerous studies with animals with serious diseases such as heart attack, liver failure, stroke and traumatic brain injury have shown that adult stem cells can be injected intravenously or transplanted some distance from the site of injury, since they migrate to the site of injury, differentiate into the appropriate cell type and begin to repair the damage. There have been astonishing levels of success with disorders such as heart attack and liver failure, and dramatic reductions in mortality.

Those studies show that adult stem cells have the ability to migrate to the site of injury and repair the damage. In some cases, differentiation of the stem cells at the site of injury was also clearly demonstrated. That is extremely advantageous, since it means that adult stem cells in many cases could be injected or even mobilised from internal stores rather than surgically transplanted. That is particularly helpful in cases like stroke, heart attack and spinal cord injuries, where surgery could be dangerous. It also means that the adult stem cells do not need to be either dedifferentiated or differentiated before transplant, since local signals in the body direct events appropriately. It therefore provides a very elegant, quick, simple and safe procedure. However, that procedure cannot be carried out using embryonic stem cells, because of the severe risk of tumour formation when injecting or transplanting undifferentiated embryonic stem cells into the body.

I conclude by arguing that there seem to be strong grounds for concern about the conclusions of the report. I hope that they will be taken into account before it leads to potentially irreversible developments that could harm those whom it is intended to help.