Benefits and risks associated with the use of stem cells in medicine

Stem cells have great potential, in treating patients with currently untreatable conditions, growing organs for transplants, and research.

To collect them they can be removed from human embryos that are a few days old. These could be embryos left over from fertility treatments or cloned from a patient's own cells (therapeutic cloning). Sometimes adult stem cells can be used, but they are not as useful as embryo stem cells because they can only differentiate into a limited number of different specialised cells.

Stem cells could be used for:

  • making new brain cells to treat people with Parkinson's disease
  • rebuilding bones and cartilage
  • repairing damaged immune systems
  • making replacement heart valves

However, there are clinical, ethical and social issues with their use. These issues will be different for growth and transplant of adult, embryonic and therapeutically cloned stem cells. They will also depend on whether the stem cells are to be used for therapy or research.

It is important to obtain a balanced view. Sometimes, there are no right or wrong answers, or even answers at all.

Some factors to be considered regarding use of stem cells include:

Clinical issues

  • There is no guarantee of success, for example, the use of stem cells in replacing nerve cells lost in Parkinson's disease patients has had limited success.
  • The current difficulty in finding suitable stem cell donors.
  • The difficulty in obtaining and storing a patient's embryonic stem cells. These would have to be collected before birth - some clinics offer to store blood from the umbilical cord when a person is born.
  • Mutations have been observed in stem cells cultured for a number of generations, and some mutated stem cells have been observed to behave like cancer cells.
  • Cultured stem cells could be contaminated with viruses which would be transferred to a patient.

Ethical issues

  • Unused embryos produced by in vitro fertilisation (IVF) can be a source of stem cells.
  • For therapeutic cloning, is it right to create embryos for therapy, and destroy them in the process?
  • Embryos could come to be viewed as a commodity, and not as an embryo that could develop into a person.
  • At what stage of its development should an embryo be regarded as, and treated as a person?

Social issues

  • Educating the public about what stem cells can, and can't do, is important.
  • Whether the benefits of stem cell use outweigh the objections?
  • Much of the research is being carried out by commercial clinics, so reported successes are not subject to peer review. Patients could be exploited by paying for expensive treatments and being given false hope of a cure as stem cell therapies are only in their developmental stages.

Tissue transplantation and rejection

If someone has heart failure then they may be treated with a heart transplant. The patient that receives the new heart must take immuno-suppressant drugs which will stop their immune system from attacking the new heart and organ rejection occurring. If the patient's own stem cells could be used to grow a new heart, then the body would not reject the transplanted organ.

This is an area of medicine that scientists are carrying out a lot of research into. Being able to grow the organs that a patient needs would save a lot of money and overcome the problem of trying to find an organ donor. This technology is still new and a lot more work needs to be done before it becomes commonplace in medicine.