- Stem cell: An unspecialised cell that can divide to produce more stem cells or different kinds of specialised cell.
- In human embryos that are a few days old they have embryonic stem cells. These cells can be differentiated into almost any human cell such as neurones, muscle cells etc. However, one the stem cells have differentiated, they cannot change again.
- Stem cells found in differentiated body tissues (e.g. bone marrow), which are called adult stem cells, can only differentiated into a few types of cell while embryonic stem cells are the opposite; they are known to be pluripotent as they can transform into any type of cell.
- In many plant cells they don’t lose the ability to differentiate unlike animal cells.
Stem Cell treatments
- Since the 1960s, adult stem cells from bone marrow have been used to treat leukaemia, a cancer of certain white blood cells. To do this, the patient’s white blood cells are destroyed and replaced with adult stem cells from someone else. These cells multiply to produce healthy white blood cells.
- This is known as a bone marrow transplant. However, the treatment doesn’t always work because if the cells are too different, the patient’s body destroys it.
- This problem can be solved by cloning. If a cloned embryo is created by the skin cell of the patient with leukaemia the embryonic stem cells on the embryo can be taken and used to produce the cells that make white blood cells. These will survive in the patient as their body would recognise the new white blood cells as their own cells.
- This technique could treat many more problems than adult stem cells could as embryonic stem cells can differentiate into almost every kind of cell. However, that means that this could be used illegally by people to produce human clones.
- Scientists have also been investigating ways of reprogramming specialised cells into stem cells. This would avoid the ethical problem with using embryos if it works. But further research is required to make any treatment with stem cells safe as if injected into the body they may produce the wrong kind of cell or even create cancer cells.
People don’t like using embryos as they believe it is a form of murder as they are destroying a potential human life. However, some say that curing patients who are suffering is more important than potential life.