By Professor Harry Moore
Centre for Stem Cell Biology, University of Sheffield
As the fiercely controversial debate over embryonic stem cell therapy gathers pace, two personal and opposing accounts argue the case for and against.
Professor Harry Moore sets out his views below.
Medical progress, by its nature, is never straightforward.
Prof Moore: "Some cell therapies may be available in 10 to 15 years"
With any new treatment there are always risks and potential side effects.
But I believe the potential that stem cells offer to revolutionise the treatment of several degenerative diseases, as well as spinal cord injury, definitely merits research.
The legislation in place in the UK for embryo research since 1990, and revised in 2001, is perhaps the most advanced in the world and strictly governs what studies can be undertaken.
This is welcomed by the vast majority of doctors and scientists in the field and protects both patients and researchers.
Of course the maverick scientist will always exist (and needs to be safeguarded against).
And stem cells are not the panacea for every disease (as might be thought from all the media hype).
IF... CLONING COULD CURE US
Thursday, 16 December, 2004
But, given the progress made in the last few years, some stem cell therapies may well be readily available within 10 to 15 years.
The challenge is to develop effective and safe cell therapies - which will take time, money and perseverance.
Embryonic stem cells in the laboratory retain the ability to form specific cell types such as insulin-secreting cells, nerves and heart cells.
If transplanted, these cells might halt and even cure patients of diseases such as Type 1 diabetes, Parkinson's disease or heart failure.
Transplantation studies into animals with these cells have shown much promise.
This research represents an important change in our thinking on how, in the future, we might treat these debilitating illnesses where patients require long-term care, and drugs cannot cure the condition.
Presently, a major stumbling block for cell transplantation is the lack of suitable tissue for donation.
For instance, trials to treat diabetes with pancreatic cells (which regulate blood glucose by secreting insulin) from dead donors have shown good success.
This transplantation therapy controls diabetes much better than insulin injections alone, giving patients the prospects of a much better quality of life.
But often cells from two or three donors are required to treat one patient.
This is not only very impractical but there are potential long-term risks of transmission of other blood-borne diseases to the patient.
Because embryonic stem cells proliferate indefinitely they represent an inexhaustible supply of cells, which can be cultured in quarantine conditions, free from the risk of other infectious agents.
A question often asked is: why use human embryos and embryonic stem cells - would it not be more ethical to use adult stem cells from bone marrow, babies' cord blood or other tissues?
In fact adult stem cells are used to treat certain conditions.
But I, and many other scientists, believe that only embryonic stem cells have the true capacity to develop into all the different cell types of the body and therefore represent the greatest potential for future cell therapies.
Embryos are donated by couples undergoing IVF treatment after independent counselling, are surplus to their clinical need and would often otherwise be destroyed.
These donors have confidence in the regulatory framework and inspections of the HFEA and are motivated into giving embryos with the hope research will lead eventually to clinical applications.
Nevertheless, the potential of other stem cells should, and is, being explored.
Recent experiments suggest that adult stem cells may have some capacity to change into other cells for therapy.
In time, we may be able to reprogramme many cells to other functions in the body in which case early embryos and embryonic stem cells may not be necessary.
But, in the meantime, I believe the judicious use of human embryos and the development of embryonic stem cell lines provides our best route for developing new therapies to treat a range of devastating degenerative diseases.
Professor Harry Moore's article was written to coincide with BBC Two's If... Cloning Could Cure Us, broadcast on Thursday, 16 December 2004, at 2100 GMT.