Cell differentiation, stem cells and ethics

In a nutshell

Stem cells are undifferentiated cells that can undergo cell division and then later be differentiated to form specialised cells that have specific features and functions. Stem cells are a huge research interest among scientists, but the use and research of them is controversial.

Stem cells

Definition

Stem cells are undifferentiated cells in our bodies. That means that they have no specific features yet, but they have the potential to develop them. Stem cells are really important as it means we can produce various types of specialised cells from them. They can also be used in research to understand the human body more and produce medicines. There are several types of stem cells.

Embryonic stem cells

These stem cells form when a zygote is formed from an egg and sperm cell. They are the first types of cells to form. Embryonic stem cells can differentiate to form almost any kind of cell.

Adult stem cells

These stem cells are found in specific adult organs and can only differentiate into related cell types.

Example

Stem cells found in bone marrow can differentiate to form new blood cells.

Meristems

Meristems are tissue that contain stem cells in plants. These retain the ability to differentiate into any type of cell in the plant throughout the whole life of the plant. Meristems are usually found close to the tips of shoots and roots.

Research with stem cells

Uses

Embryonic stem cells can be used to produce certain medicines.

Example

Embryonic stem cells could be artificially differentiated in a lab to produce insulin-producing cells that can be given to a person with diabetes; or they could be used to produce new neurons for people who have lost brain matter in diseases such as Alzheimer's disease.

Adult stem cells can be used in clinical medicine as a transplant for patients with blood conditions such as leukaemia. However, there is a risk of the stem cells being rejected by a person's immune system which can make them very ill.

Meristems can be extracted and used to clone a plant with a lot of care and effort. This can help us grow new plants with the qualities we like from another plant.

Ethical debate

There is some debate around whether the use and research of stem cells is worth it.

FOR	AGAINST
If used properly, stem cells can be used therapeutically to replace damaged tissues or organs.	Even if we successfully extract stem cells, it is really difficult to control differentiation. This may result in many experiments failing, which can be a waste of money.
Research into stem cells may open up the possibility of cloning, which may allow us to personalise treatment. Example A person's own stem cells could be used to produce differentiated cells, which would have less chance of rejection by the immune system.	Embryonic stem cells have to be taken from an embryo, which damages and kills the embryo. Some people view this as taking a life as an embryo has the potential to develop into a person. Some people think that it is interfering with the natural way of life, and may hold religious or ethical beliefs against it.
Using stem cells for research may be a better use of embryos that are produced in a fertility clinic that would otherwise be thrown away.	Some stem cells have shown mutations that make them behave like cancer cells. These can divide uncontrollably to form tumours.
By using and studying embryonic stem cells, scientists can learn more about the process of development.	If a contaminated stem cell culture is transplanted into a patient, the patient may suffer from a disease caused by the contaminating bacteria or virus. This poses a much greater risk to their health.