Due to their ability to differentiate into multiple cell types, stem cells have huge potential in the therapeutic treatment of disease
For many countries, such as the USA and some countries within the EU, the use of embryonic stem cells is banned, even for research
In other countries, such as the UK, the use of embryonic stem cells is allowed for research but is very tightly regulated
Embryonic stem cells can be one of two potencies:
Totipotent if taken in the first 3-4 days after fertilisation
Pluripotent if taken on day 5
The embryos used for research are often the waste (fertilised) embryos from in vitro fertilisation treatment
This means these embryos have the potential to develop into human beings
This is why many people have ethical objections to using them in research or medicine
Use of multipotent adult stem cells
Adult stem cells can divide (by mitosis) an unlimited number of times but they are only able to produce a limited range of cell types
A small number of adult stem cells are found in certain tissues within the body such as:
Bone marrow - used to produce different types of blood cell
Brain - used to produce different types of neural and glial cells
These small numbers of stem cells remain to produce new cells for the essential processes of growth, cell replacement and tissue repair
Research is being carried out on stem cell therapy, which is the introduction of adult stem cells into damaged tissue to treat diseases (e.g. leukaemia) and injuries (e.g. skin burns)
The use of adult stem cells is less controversial than embryonic stem cells because the donor is able to give permission
For example, many people donate bone marrow to help treat leukaemia patients
However, if multipotent stem cells are being donated from one person to another they need to be a close match in terms of blood type and other body antigens
There is a chance that the cells used are rejected by the patient's immune system
Ideally, the patient's own adult stem cells are used to treat them, as there is a much lower chance of rejection
Table Showing the Uses of Stem Cells in the Treatment of Certain Conditions