Therapeutic cloning

Transplanting stem cells

Adult stem cell transplants use a patient's own stem cells. They are therefore genetically identical and will not be rejected by the patient's immune system.

There are also fewer complications if the stem cells come from a close member of the family. Alternatively, donor cells can come from a person with closely-matched tissue types.

Embryonic stem cells will always come from a donor – unless stem cells were collected from the patient as an embryo.

Therapeutic cloning

Therapeutic cloning could produce stem cells with the same genetic make-up as the patient.

The technique involves the transfer of the nucleus from a cell of the patient, to an egg cell whose nucleus has been removed.

The technique involves the transfer of the nucleus from a cell of the patient, to an egg cell whose nucleus has been removed.

Stem cells produced in this way could be transferred to the patient. Although human stem cells have been produced in this way, and used in research, there is no evidence that, as yet, they have been used to treat anyone.

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. But 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 variables which would be considered when discussing stem cells include:

Clinical issues

  • There is no guarantee how successful these therapies will be, for example the use of stem cells in replacing nerve cells lost in Parkinson’s disease patients.
  • 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

  • A source of embryonic stem cells is unused embryos produced by in vitro fertilisation (IVF)
  • 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.
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