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Let me try to explain why I believe that stem cell research is so important. I shall then move to why embryonic stem cells have to be researched, as well as adult stem cells in parallel. Early embryos--blastocysts--that are under one week old consist of between 100 and 200 individual cells only. They are only one fifth of a millimetre in diameter, which is smaller than a printed full stop.
In general, it is intended to carry out the research on embryos that have been produced for in vitro fertilisation treatment. Not all of them are used. In case they are needed for further treatment, the vast majority are stored in liquid nitrogen to prevent their growth and are ultimately destroyed with the consent of the donor. Between 1991 and 1998, a total of 763,509 embryos were created by IVF methods. Almost half were used for infertility treatment but, as my hon. Friend the Member for Norwich, North (Dr. Gibson) pointed out, more than 273,000 had not been used and, by consent, were destroyed; such embryos will be used in stem cell research.
As the hon. Member for Richmond Park (Dr. Tonge) said, millions of pre-embryos or embryos are discarded naturally without women being aware of the loss. Those embryos are so small that I cannot see that they have any life structure--not even a blob for a brain or a streak for a spinal cord.
As a chemist in a former existence, I am aware of some amazing research that is being carried out throughout the world--universities such as Sheffield are leading it--whereby large molecules can recognise other molecules and attract them, in a process called molecular recognition. The molecules can assemble in fairly large complexes and already show signs of doing what machines do in factories, but at a molecular level.
Many of the molecular recognition complexes are capable of amazing things such as conducting electricity. Chemists and biochemists involved in the research are convinced that the process is the way in which life began. More than 30 years ago, an experiment was conducted by Professor Urey. With primordial gases in a discharge tube, he emulated the conditions that must have existed on primordial earth. He passed an electric discharge through the tube. A yellow liquid collected that containing the bases of life--amino acids and the four bases that go into the nucleic acids.
At this stage, we do not know how those fairly complex chemicals, produced in such a simple way, came together in a recognition process and began the elementary stages of primitive life. However, scientists have predicted-- I am one who believes the prediction--that, some time this century, through the process of molecular recognition, we will be able to generate one of the simplest forms of life synthetically. People might find that repulsive--I do
Furthermore, scientists believe that the DNA in the nucleus of a cell is a blueprint, as many hon. Members have suggested. It is capable of attracting--and does attract, in scientists' opinion--other molecules and of assembling them. In my opinion, those small embryos--the hon. Member for Richmond Park called them pre-embryos--are chemical factories in which molecular recognition occurs and clumps of molecules come together. It is fascinating how it goes through the stem cells and develops into the complex chemical factories that we all are. There will be some great discoveries this century, and I am sure that this year has seen the beginning of a major debate.
Fresh embryos as young as a few days old consist, of course, of pluripotent stem cells: cells that can differentiate into all other cells from which life is ultimately constructed. We do not know what chemicals--for chemicals they are--act as the triggers to differentiate the cells into all the other cells in our skeletons, such as nerve cells, muscle cells, skin cells and so on.
In my opinion, it is absolutely essential to know what chemical triggers differentiate primitive stem cells from other cells. Why is it important to understand that? Cancer is a disruption of normal cell differentiation and in order to understand the more than 100 different cancers that afflict us and to be able to control the development of those cancers we must fully understand cell growth. Indeed, after surgery for cancer, when huge amounts of tissue are removed internally, or after chemotherapy or radiotherapy, when normal tissues are badly damaged, it would be nice to be able to replace those tissues and return people to as normal a state as possible, their cell division having gone so hopelessly wrong. That is another reason why this research is so important. It gives great hope to many thousands of people suffering from cancer all over the world.
As far as I understand the research, the aim is to use the pluripotent stem cells, which can be extracted from few-day-old embryos, to create banks of the different cells that grow into body tissues--cell lines. Cells can be grown on in the right culture medium. The growth and differentiation of stem cells can also be halted by cooling them down and storing them in liquid nitrogen. Therefore, an endless source of stem cells might not be necessary once the cell banks, cell lines and tissue banks have been created--at least not for the study of cell growth and differentiation.
There is also the possibility of repairing major organs in the body such as the heart and kidneys, thus reducing the need for organ donation. I am sure that right hon. and hon. Members are aware that there has been a serious shortage of organs for transplantation, which has been made worse recently by the adverse publicity over removed organs being stored by pathology departments in various hospitals.
We are talking about long-term research and we do not know how far we can go with it or where it will take us, but if we do not start the research, which has shown great promise in animal experiments, we shall never know what good we can do for society.
It is true that stem cells are also present in adults. They are multipotent rather than pluripotent, which simply means that they do not have the capacity to produce as many cell types as embryonic stem cells. In any case, they are aged and there is the consequent possibility that they have mutated, which is a danger. Additionally, they are extremely difficult to isolate free of contaminants. Nevertheless I accept that advances are being made in adult stem cell research, but that is not the reason, often cited by those who oppose embryonic stem cell research, for not allowing parallel research to begin on the development of pluripotent embryonic stem cells.
Ms Kelly: My hon. Friend cites all the disadvantages of using adult stem cells as opposed to embryonic stem cells. Does he agree that there are also advantages of using adult stem cells as opposed to embryonic stem cells? For instance, they are much less likely to be rejected by the adult recipient. In addition, their growth is much easier to control than that of embryonic stem cells.
Dr. Iddon: I had not finished my remarks on adult stem cells, but I admit that if it were possible to switch all the research to adult stem cells, I too would encourage that. There is no doubt about that. However, we just do not know what the chemical triggers are for differentiation--which will be best explained by research on embryonic stem cells. The research must be in parallel. We cannot delay one whole sphere of research and concentrate on the research on which my hon. Friend the Member for Bolton, West (Ms Kelly) would like to concentrate.
If adult stem cells prove to do everything that we require of them, I am sure that the Human Fertilisation and Embryology Authority will reduce the number of licences that it grants for embryonic stem cell research. Each new research programme will, after all, require a fresh licence.
Another difference between adult stem cells and embryonic stem cells is that the former seem to lose their ability to differentiate after long storage in culture. However, my hon. Friend the Member for Bolton, West will be pleased to know that there is new hope that adult stem cells can be reprogrammed and, essentially, taken back in time, so that they regain the ability to differentiate as embryonic stem cells are able to. That might allow scientists to turn one tissue type into another tissue.
I accept that stem cells are present in foetal tissue, placental tissue and umbilical cords, especially in the cord blood. However, they also have limited ability to differentiate, unlike embryonic stem cells.
I should like briefly to address the issue of cloning, particularly therapeutic cloning. It is rather unfortunate that we have to use the word cloning, which has been given such a bad press by science fiction writers. The hon. Member for North Devon (Mr. Harvey) mentioned the language being used by scientists, and that language does concern our constituents. In this debate, however, it is important to understand the difference between therapeutic cloning, which the regulations deal with, and reproductive cloning, which they do not deal with. Indeed, even if reproductive cloning were technically possible with humans, I would not support it. I do not know one hon. Member who would support it. Clearly the Government would not support it. It is illegal now, and it will remain illegal.
Why is therapeutic cloning necessary? Obviously the problem is that unless tissues are grown to avoid rejection by the immune system of the person into whom they are to be implanted, rejection will occur. To date, human embryos have only ever been created from eggs and sperm. However, the Dolly the sheep experiment in 1997 showed that embryos can be created without sperm. That is what the process of cell nuclear replacement is all about. As well as sheep, the process has been applied to cows, goats, pigs and mice.
In order to avoid the rejection problem, it is necessary to take a cell from the tissue or organ of a recipient patient, extract its nucleus--which contains most of the patient's DNA and genetic identity--and implant the nucleus in an unfertilised egg with its nucleus removed. The fusion produces an embryo fusion or blastocyst from which the stem cells can be extracted and grown into tissues that can be implanted in that patient without rejection. That is cloning and, theoretically, if such an embryo were allowed to develop full term through implantation in a womb, human cloning would be possible. For that reason, tough regulation of the process is absolutely essential, and that is what the regulations that we shall discuss on Tuesday are about.
More than 50 inherited metabolic diseases--some not so well known as others--are caused by defects in mitochondrial DNA, which is present in the cytoplasm surrounding the nucleus of the mother's egg. It has now become theoretically possible to remove the nucleus of the mother's egg and to transfer it into a donor egg with
I emphasise that this is not reproductive cloning, given the genetic make-up of the child likely to born through use of this technique. My hon. Friend the Member for Bolton, West said that, if a human being were ever born following such a procedure, he or she would have two mothers and one father. I do not accept that, because most of the DNA is in the nucleus of the egg. Only a small part--the part responsible for energy processes in the body--is present in the cytoplasm. The DNA in the nucleus of the egg is responsible for the genetic fingerprint of a human being. I totally reject what my hon. Friend said earlier.