What are Stem Cells? | Stem Cells Australia | What are stem cells? | Stem Cells Australia

What are stem cells?

Stem cells are a special type of cell that have the remarkable ability to make copies of themselves, as well as create more specialised cells found in the body.

Different types of stem cells have different qualities that determine when researchers and doctors use them in their work. Click on links below to learn more.

What are stem cells?

What are tissue stem cells?

Tissue stem cells are found in organs all over the body. They have the ability to make cells specific to the tissue of the organ where they are found and are required for the normal function of that organ.

One of the most well recognised tissue stem cells are those found in bone marrow. These blood or haematopoietic stem cells are responsible for making red blood cells, white blood cells and platelets. These include:

The red blood cells that transport oxygen around our body. They only have a life span of 120 days and are continuously being made in the bone marrow
The white blood cells, which are important for protecting you against infection and
Platelets, which play a major role in forming blot clots.

If something goes wrong with the stem cells within the bone marrow production line, the patient could develop anaemia (lack of red blood cells), leukaemia (too many abnormal blood cells) or suffer a massive loss of blood (failure of blood to clot).

Tissue stem cells can also be found in other organs such as the skin, the lining of the gut, liver and even the brain. You may also have heard of ‘mesenchymal stem cells’ or MSCs (also called ‘mesenchymal stromal cells’). These cells are found in bone marrow, fat and other tissues and in the lab can make cartilage as well as bone and fat. MSCs will have different properties depending on where in the body they are obtained and how they are handled and grown in the lab.

What are pluripotent stem cells?

Pluripotent stem cells include those obtained from embryos – called ‘embryonic stem cells’ – or can be generated in a lab from a patient’s or donor’s cell - called ‘induced pluripotent stem cells.’ These stem cells are different to tissue stem cells because scientists can make large numbers of a particular type of body cell from them on demand. However, it is important that the scientists give pluripotent stem cells the right signals otherwise the stem cell might turn into something unintended.

Embryonic stem cells

Embryonic stem cells are isolated from IVF embryos that have been donated for research. In Australia it has been possible to use human embryos in research but only for licenced and ethically approved research projects. Once isolated, embryonic stem cells can be readily grown and expanded in the lab and can also be frozen and stored for future use. Researchers around the world use embryonic stem cells to learn more about how the body develops and the processes that determine how a stem cell turns into a particular body cell. Ultimately, such information will help scientists develop new cell-based therapies.

Induced pluripotent stem cells

Induced pluripotent stem cells (or iPSCs) are stem cells that are made in the lab by converting a cell from one part of the body back into a ‘blank slate’ stem cell. They behave in a very similar way to embryonic stem cells and can be used to make almost any type of body cell in the lab. Scientists are using iPSCs to understand not only normal development but also what happens during disease. It is possible to take the cell from a patient with a particular disease, for example Motor Neuron Disease, and then make large numbers of the affected cells that can be studied in the lab. Using such an approach, scientists can test promising new drugs as well as potentially use iPSCs as a source of cells for regenerative medicine.