Stem cells in medicine

In a nutshell

Stem cells are cells that have not become specialised yet. They can be used in transplants and in therapeutic cloning as a way to treat many medical conditions. Stem cell treatments come with many issues, therefore they raise many scientific, ethical and social questions.

Stem cell transplants

Transplants of the bone marrow, which contains stem cells, have been carried out since $1968$ . There are very few stem cells in the bone marrow, which is why they are instead isolated from the blood. Blood left in the umbilical cord and placenta after a baby is born is a source of stem cells. This blood is easy to collect and store.

Rejection of stem cell transplants

Rejection of stem cell transplants by a patient's immune system is a problem. One way to avoid this problem is to find a close match between donor and patient such as siblings. Another way to avoid transplant rejection is to give the patient drugs that suppress their immune system. These are known as immunosuppressants.

Therapeutic cloning

Definition

Therapeutic cloning is a way to produce stem cells with the same genes as the patient, ensuring they would not be rejected by their immune system. The process involves nuclear transfer.

Note: There is no evidence that this has been used to treat any humans as of yet.

Biology; Global challenges; KS4 Year 10; Stem cells in medicine

1.	A human egg cell.
2.	Patient's body cell.
3.	The nucleus is removed from the egg cell.
4.	A nucleus from a patient's body cell is placed into an egg that has had its nucleus removed.
5.	The cells are stimulated to divide.
6.	An embryo is produced and is allowed to grow.
7.	After $4-5\ days$ , the stem cells are removed.
8.	Stem cells from the embryo are cultured. The stem cells are used to treat the patient and the embryo is discarded.

Scientific, ethical and social questions

Many questions arise from stem cell therapy. One important scientific question that must be considered is 'how successful might these therapies be?'. There are safety concerns, as stem cells kept in culture can show similarities to cancer cells, after around $60$ divisions mutations in the cells have been observed and it is possible for viruses to be transferred to these stem cells.

There are also ethical questions such as 'Is it morally right to create an embryo with the intent of destroying it?'. Some people consider an embryo a human life and would therefore disagree with stem cell therapy.

Social questions such as considering whether the benefits outweigh the objections and the requirement for further public education on this issue have arisen.