An overview of stem cells, the regulation of human embryo research and the prohibition of human cloning in Australia.
What are stem cells?
- Stem cells are ‘unspecialised’ cells that have the unique potential to develop into ‘specialised’ cell types in the body (for example blood cells, muscle cells or nerve cells). This can be either for growth and development, or for replenishment and repair.
- Stem cells occur at all stages of human development, from embryo to adult but their versatility and numbers tend to decrease with age.
- Given the right conditions in the body or the laboratory, stem cells (unlike muscle cells, nerve cells and or blood cells) can replicate themselves many times over.
- When a stem cell replicates, the resulting cells can either remain as stem cells or can become specialised cells.
What are embryonic stem cells?
- Embryonic stem cells, as their name suggests, are derived from the early embryo. They have the potential to develop into all cell types in the body.
- In Australia, human embryonic stem cells are derived from human embryos that are excess to the needs of patients undergoing assisted reproductive technology (ART) treatment programs and have been donated to research by the couple for whom they were created. They are not derived from eggs fertilised in a woman’s body.
- Embryonic stem cells can also be derived from embryos created by somatic cell nuclear transfer (see 'Cloning' section below).
What are adult stem cells?
- Adult stem cells (often called somatic stem cells) are found in many organs and tissues of the body. Their main function is to replace cells that have died in the tissue or organ where they are located.
- Adult stem cells extracted from the bone marrow of patients or compatible donors are used routinely in treating diseases such as leukaemia. (All blood cells in the body are manufactured in the bone marrow.)
- Umbilical cord blood, extracted from the umbilical cord and placenta when a baby is born, is a rich source of adult stem cells. These cells may be useful for medical research or therapeutic use in the future.
What are induced pluripotent stem (iPS) cells?
- Adult cells can be reprogrammed into cells that have similar properties to embryonic stem cells – these are termed induced pluripotent stem (iPS) cells.
- Reprogramming can be induced through the action of a small group of proteins in the adult cells.
- iPS cells were first generated in 2006. Many research groups have now produced iPS cells, including in Australia.
- A number of methods can be used to produce iPS cells. Some alter the DNA sequence of the cells, such as the use of retroviruses.
- Some researchers have shown that the genes that induce reprogramming can be removed once the iPS cells are produced. Others groups have used purified proteins to induce reprogramming, avoiding the use of DNA such as retroviruses.
- Research on iPS cells may eventually lead to the development of patient-specific stem cell lines which could be used clinically without the need to use human eggs or embryos. However, additional research is required to establish whether iPS cells are sufficiently similar to embryonic stem cells to substitute for them.
What are the potential uses for stem cells?
Researchers and clinicians are developing stem cell technologies to:
- improve our understanding of fundamental processes in biology
- contribute to novel treatment methods in the health care setting, by producing:
- models of diseases – for example, stem cells can be derived from patients with known genetic disorders, allowing researchers to study the disease process
- models for drug screening – novel compounds to treat diseases can be tested using cell lines derived from stem cells
- personalised therapeutics – stem cells may be a source of replacement cells that could be used to treat disease.
- "Cloning" is an umbrella term traditionally used by scientists to describe different processes for duplicating biological material.
- The possibility of human cloning arose when Scottish scientists at the Roslin Institute created the much-celebrated sheep 'Dolly' (Nature 385, 810-13, 1997)
- Reproductive cloning is banned in Australia under the Prohibition of Human Cloning for Reproduction Act 2002. Click here for more information.
- Therapeutic cloning, also known as somatic cell nuclear transfer (SCNT) is permitted in Australia under a licence issued by the NHMRC Embryo Research Licensing Committee.
- SCNT was the technique used to create the first cloned mammal, 'Dolly' the sheep. SCNT involves isolating a somatic cell from an adult body, often a skin cell, and transferring the nucleus from that cell to an egg from which the nucleus has been removed. This new cell is then stimulated to begin embryonic growth.
- The first human embryonic stem cell lines derived from SCNT research were announced in May 2013 by Mitalipov and coworkers from Oregon Health and Science University.
- Parthenogenesis is a process where an unfertilised egg is induced to divide and develop as though it had been fertilised.
- Parthenogenetic embryos cannot be used for reproduction as they will not develop past an early stage of pregnancy. Furthermore they are prohibited embryos under section 20 of the Prohibition of Human Cloning for Reproduction Act 2002.
- Creation of embryos by parthenogenesis and their use for research is permitted in Australia under a licence issued by the NHMRC Embryo Research Licensing Committee.
- Embryonic stem cell lines derived from a parthenogenetic embryo are genetically matched to the woman who provided the egg.
Use of human embryos to derive embryonic stem cell lines
Research Involving Human Embryos Act 2002
- The use of human embryos to derive human embryonic stem cell lines for research is governed by the Research Involving Human Embryos Act 2002. The Act allows the use under licence of embryos created through ART that are no longer required by the couples or that are unsuitable for implantation. The Act also allows the creation and/or use of certain other types of embryos for research under licence.
Assisted Reproductive Technology (ART) guidelines
- ART includes techniques such as IVF (in-vitro fertilisation, or fertilisation in an artificial environment such as a test tube).
- ART itself is subject to the Ethical Guidelines on the use of Assisted Reproductive Technology in Clinical Practice and Research (2007) and the requirements of the National Statement on Ethical Conduct in Human Research (2007) issued by the NHMRC.
- The ethical guidelines on ART outline the comprehensive consent process for couples who wish to declare embryos as excess to their requirements, and to allow the embryos to be used for research purposes.
- The ethical guidelines also outline the consent process for people giving consent to the use of their reproductive or genetic material or cells in the creation or use of embryos for research
Embryo Research Licensing
- Human embryos can only be used for research purposes in Australia if authorised by a licence issued by the NHMRC Embryo Research Licensing Committee.
Use of cell lines in research
- The use of human or animal cell lines in health and medical research is covered by guidelines and other statements issued by the National Health and Medical Research Council (NHMRC).
- Researchers should abide by the provisions of the National Statement on Ethical Conduct in Human Research (2007)
More information and advice on the regulatory framework
- More information and advice on the regulatory framework relating to human cloning and research involving human embryos, and Commonwealth and State and Territory legislation, is available on the NHMRC's Policy and Guidance web page.
Facts and figures on embryos, licences and funding
What are the licence holders hoping to achieve through the use of human embryos for research?
- The licences issued to Genea Limited will enable them to undertake research leading to improved IVF success rates; gain a better understanding of embryo metabolism; undertake specialised work to derive embryonic stem cells and to attempt to create embryos by somatic cell nuclear transfer and then, if successful, to attempt to derive embryonic stem cells from the embryos.
- Fertility Australia (trading as Fertility East Assisted Conception Clinic) and the Division of Biological Engineering, Faculty of Engineering, Monash University have been issued with a joint licence to create parthenogenetic embryos and to attempt to derive embryonic stem cells from these embryos.
- Monash IVF has been issued with a licence to investigate the interactions between embryos and the endometrium to provide insight into the requirements for successful ART pregnancies.
Number of embryos and eggs
- There were 118700 embryos in frozen storage in Australia in 2006 (the most recent time for which data are available). Almost all of these were embryos were intended to be used to achieve a pregnancy.
- Very few ART embryos in storage have been declared to be excess to ART requirements.
- At 31 August 2013:
- The total number of embryos authorised to be used under current licences was 1795
- The total number of clinically unusable eggs authorised to be used under current licences was 9400
- 1056 excess ART embryos had been used in licensed research in Australia
- 929 clinically unusable eggs had been used in licensed research in Australia
- Information on embryo and licence numbers
- Information about the results of the licensed research is available in the NHMRC Embryo Research Licensing Committee Reports to Parliament.
How many excess ART embryos or eggs will be used in the licensed activities?
There are currently 10 active licences issued by the NHMRC Embryo Research Licensing Committee:
|1000 eggs / 285 embryos|
Fertility Australia (trading as Fertility East Assisted Conception Clinic) and Division of Biological Engineering, Monash University
|Licence 309722||200 embryos|
These details are included in the information on each licence that is provided on the NHMRC website.
Funding of Stem Cell Research
The Australian Government funds stem cell research through various grant schemes.
International website links
The following websites provide useful and authoritative information on stem cells, cloning and related issues