“Stem cells and regenerative medicine: prospects for realising the Prometheus myth”

Professor John Rasko, Centenary Institute

Wednesday 6 July 2011, 6.30 for 7 pm

Lecture Theatre 106, New Law Building, University of Sydney

Professor John Rasko was appointed to the first clinical gene therapy position in Australia. Currently, he is head of the gene and stem cell therapy programme at the Centenary Institute and is a Professor in the faculty of medicine at Sydney University. At the general meeting of the Society on Wednesday 6 July, Professor Rasko gave a wide-ranging talk on the status of cellular therapies for regenerative medicine and cancer treatment and the potential and use of both embryonic and adult stem cells in the treatment of a wide range of diseases. Importantly, there was a comprehensive discussion on the ethical issues in relation to the use of both embryonic and adult stem cells, not only in the treatment of disease but also the implications for technologies such as in-vitro fertilisation. 

The Centenary Institute has a large research programme for cellular medicine and extraordinarily sophisticated facilities for the manufacture and cultivation of biological material. This includes four specialised laboratories with hyper-pure air flow, positive air pressure differentials, both for preventing contamination and the release of biologically-active material and sophisticated human-access protocols. 

Research programmes include techniques such as extraction and cultivation of red cells and bone marrow prior to treatments such as chemotherapy and radiation therapy in order to speed up patient recovery and exploring the extent to which adult stem cells might be used as a source of genetic material to help rebuild damage organs such as the liver, and blood and bone marrow. 

Professor Rasko explained the potential of embryonic stem cells that, one day, might be used to treat a range of diseases by replacing damaged or diseased tissue. Embryonic stem cells are taken from embryos at the time when little differentiation between cells has yet taken place. These stem cells theoretically are able to be cultivated and differentiated as “master cells” that could produce all types of fully-differentiated tissue in the body. Despite the theoretical potential for these, progress has been slow. The medical drawbacks of using embryonic stem cells are that the embryo has the same immune signature as the mother and father, so recipients of tissue cultivated from these cells would mean constant immunosuppressant therapy. So far, only three clinical trials have been undertaken. But a more significant challenge for embryonic stem cells may well be the moral issues. Pro-life groups have opposed the use of embryonic stem cells because they believe that cells taken from an embryo have the potential to form a complete individual; to them, destroying such an embryo amounts to taking a human life.

 An alternative to using embryonic stem cells is to take adult cells and to reprogram them to make them the same as embryonic cells. In the last few years, there appears to have been significant progress in making so-called “induced pluripotent stem cells”. If this technology turns out to be viable (and there are still many challenges that have been identified), it could solve a number of the issues of embryonic stem cells. For example, because adult cells could be taken from the individual requiring treatment, induced pluripotent stem cells could be used without the need for immunosuppressant therapy. It also avoids the moral controversy that surrounds the destruction of an embryo. But this may not be the panacea that many had hoped for. There are two medical disadvantages in “reprogramming” cells: two of the transgenes required are oncogenic so pose an enhanced risk of inducing cancer in the patient; and the viruses used to carry the transgenes can be incorporated into the genetic material of cells and the consequences of this are unpredictable. It also appears that the older the organism, the more abnormalities there are in the resultant stem cell. Furthermore, the ethical issues may not be solved either. To date the efficacy of all adult stem cells need to be compared against embryonic stem cells, so the research programmes cannot be separated. In addition, there is the moral argument that if every cell in your body has the potential to produce a full range of differentiated cells (perhaps even a fully-formed individual) then it could be argued that every cell in your body has the same moral status as you do!