Human embryonic stem

 Human embryonic stem (ES) cells are derived from human embryos that are 5 to 6 days old. At this stage of development the embryo is a hollow ball of about 200 to 250 cells, no bigger than a pinhead, and is called a blastocyst. Within the blastocyst is a small group of 30 to 34 cells, called the inner cell mass. These inner mass cells are able to develop into any type of cell (pluripotent) and are the source of all the highly specialised cells found in an adult organism. The remaining cells generate all other tissues such as the foetal membranes and placenta.
Stem cell

Once the inner mass cells are obtained, they may be used to create pluripotent stem cell ‘lines’ – cell cultures that can be grown indefinitely in the laboratory. These lines are important tools for scientists, as they are all the same and it means new cells do not need to be isolated every time they want to do an experiment.

It is illegal in Australia to conduct any type of research on embryos that are conceived naturally. ES cells are taken from embryos that come from eggs fertilised in an IVF (in vitro fertilisation) clinic. Only embryos not required for implantation are used. They are donated for research purposes only with informed consent from the donors. They are not derived from eggs fertilised within a woman’s body, and embryos are not created specifically for research purposes.

ES cells can become any cell type of the body because they are pluripotent, making them attractive for developing different tissues for cell-based therapies.

Large numbers of embryonic stem cells can be grown in the laboratory relatively easily. ES cell lines are sometimes referred to as immortal, due to their ability to keep dividing (self-renew) over many generations. Therefore established cell lines can be maintained in laboratories for further research and generation of cells for cell-based therapies for many years.