These human ES cell lines have come from two different sources. One line was isolated from human foetal tissue obtained from terminated pregnancies, the other was obtained from surplus early-stage human embryos donated by individuals undergoing IVF treatment. It is cells from this second line that Bresagen will use.

Despite the fact that both tissue sources were donated with the informed consent of the donors, the destruction of embryos for stem cell isolation has attracted criticism from some pro-life, religious and bioethics groups. The central ethical argument hinges on the status of an embryo.

"The early-stage embryos used for the isolation of human stem cells are no more than six days old and are invisible to the naked eye," said Dr Tolstoshev, Manager of the Cell Reprogramming Division at BresaGen. "Furthermore, these embryos are composed of around 100-200 unspecialised cells and contain no specialised cell types such as those that make up the central nervous system, including the brain," he said.

The isolation of stem cells from human embryos is legally difficult in Australia, but researchers here are permitted to import cells that have been legally isolated in another country. A research group led by Professor Alan Trounson at the Monash Institute of Reproduction and Development recently obtained human ES cells in this way. Once isolated, stem cells can be handled in the laboratory under guidelines similar to those governing other human cell types.

Because stem cells at present must be harvested from embryonic tissue, there is the possibility of an immune reaction when they are implanted into a recipient; an outcome associated with many organ and tissue transplants. There is also difficulty in obtaining sufficient donor cells. Both problems could be overcome if stem cells could, instead, be harvested from t
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Contact: Paul Tolstoshev
ptolstoshev@bresagen.com.au
618-8234-2660
Adelaide University
5-Sep-2000