The Potential of Stem Cells for Developing New Therapies

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6. Because of their ability to reproduce themselves, and to differentiate into other cell types, stem cells offer the prospect of developing cell-based treatments, both to repair or replace tissues damaged by fractures, burns, and other injuries and to treat a wide range of very common degenerative diseases, such as Alzheimer's disease, cardiac failure, diabetes, and Parkinson's disease. These are some of the most common serious disorders, which affect millions of people in the United Kingdom alone, and for which there is at present no effective cure. Stem cell treatments, unlike most conventional drug treatments, have the potential to become a lifelong cure.

1. See memorandum by Professor Angelo Vescovi (pp. 473-475).

2. This is exemplified in recent debate over the efficacy or otherwise of stem cell transplants for Parkinson's disease. A 2001 study (reported in the New England Journal of Medicine (344:710-719)) suggesting that such a treatment had unwelcome side-effects has been cited by some as grounds for concern about the safety of embryonic stem cells. However, although these experiments were carried out with stem cells from an embryo, they were in fact from 7- to 8-week embryos and were therefore fetal and not ES cells.

7. This potential has given stem cell research a high profile and is leading to significant interest and investment in academic, medical and commercial research throughout the world. The main funding bodies gave evidence on the level of their investment in stem cell research (much of it in work on animals):

The Biotechnology and Biological Research Council has invested about £17 million in stem cell research over the last ten years.

The Chief Executive of the Medical Research Council (MRC), Professor Sir George Radda, told us that the MRC gives stem cell research a very high strategic priority and supports it to the tune of about £4.5million a year.

Since 1995 the Wellcome Trust has awarded some 15 project and programme grants specifically for stem cell research, totalling about £4.5 million. Although this is only just over half of one per cent of the total Trust spend, the Director of the Trust, Dr Mike Dexter, envisages many more applications in the future.

Although the amounts so far invested are relatively modest, all the funding bodies saw this as a major growth area.

8. The simplest way of using stem cells for therapy is by implanting a tissue which contains appropriate stem cells into an individual in whom that tissue is diseased or damaged, so that the transplanted stem cells regenerate the various cell types of that tissue. This type of therapy is in routine clinical use for treating patients with leukemia and other blood disorders by introducing hematopoietic stem cells, for example by bone marrow transplants. Despite the fact that such treatments have been successfully applied for about 20 years, few other examples of this type of approach have been developed. This is because the haematopoietic system is unusual in its accessibility and in the fact that it has evolved specifically to continuously replenish cells in the blood at high rates.

9. Recent scientific advances have opened up the possibility of treating a much wider range of disorders by isolating and growing stem cells in the laboratory. In some cases it may be possible to administer stem cells directly to an individual, in such a way that they would migrate to the correct site in the body and differentiate into the desired cell type in response to normal body signals. However, currently it seems more likely that stem cells will be grown and induced to differentiate into a defined cell type in the laboratory prior to implantation. In the longer term it may also be possible to induce stem cells to differentiate into several cell types, generating whole tissues, prior to implantation. For these approaches a much greater understanding of differentiation and developmental "signals" will be required.

10. None of our witnesses seriously questioned the therapeutic potential of stem cells for a wide range of disorders. There were differences of view as to when such therapies might be realized. Most witnesses believed that the introduction of effective stem-cell-based therapies would be a gradual process over the next five to twenty years, requiring much basic and clinical research prior to clinical application. This is a normal timespan for the development of any new treatment. Even "conventional" drugs therapies take five to fifteen years and several hundred million pounds of investment to reach the patient.

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