Wednesday, November 5, 2008

Scientists attempt stem cell breakthrough

Sydney scientists have been given the go-ahead to try to achieve a controversial world first in medical research - obtaining stem cells from cloned human embryos.

Researchers at the fertility company Sydney IVF were yesterday issued with Australia's first licence to produce cloned human embryos. By extracting stem cells from them, they hope to gain unprecedented insights into how crippling conditions including muscular dystrophy and Huntington's disease develop, and how to treat them.

The director of research and development at Sydney IVF, Tomas Stojanov, said the company had a unique combination of skills, technology and access to human eggs - 7200 of them - to be the first to succeed.

"The race is on," he said.

A national ban on the research, known as therapeutic cloning or somatic cell nuclear transfer, was lifted in December 2006 after a rare conscience vote in Federal Parliament.

The Prime Minister, Kevin Rudd - then an Opposition MP - was among those who voted to retain the ban on the process, which involves putting DNA from a patient's cell into an empty egg to produce a days-old cloned embryo, or blastocyst, from which embryonic stem cells are collected.

The director of Australians for Ethical Stem Cell Research, David van Gend, criticised the issuing of the licence by the National Health and Medical Research Council. He said cloning research was no longer necessary because of recent advances in stem cell science.

"It is unspeakable that we should continue this project of creating living human embryos with the sole purpose of destroying them when the compelling justification for such experiments has gone."

But Dr Stojanov said Australia had one of the strictest sets of ethical standards in the world for cloning research.

It did not involve the creation of a human life. "We are not creating an embryo for reproductive purposes," he said.

In 2005 British researchers produced a cloned human embryo, and in January this year a Californian company, Stemagon, produced three from 23 eggs, but neither team was able to extract stem cells from them.

Julia Schaft, who will lead the Sydney IVF project, said that only eggs that were unusable for IVF because they were immature or had not been fertilised properly, and which donors had given consent for, would be used.

The licence allows for 7200 of these eggs, which would otherwise be discarded, to be used over three years.

Her team will use three different types of cells - embryonic stem cells, cumulus cells attached to the collected eggs, and skin cells - to produce the cloned embryos.

Dr Schaft said the researchers had the necessary micromanipulation skills, and had developed special cocktails of chemicals for growing blastocysts to the five-day stage.

As well, Sydney IVF was the first, in 2004, to extract stem cells from Australian IVF embryos, and has since extracted and grown 10 more colonies of embryonic stem cells this way.

"So we have experience at every step [of the cloning process]," Dr Schaft said.

The managing director of Sydney IVF, Robert Jansen, said stem cell research sat well with the company's emphasis on helping parents avoid passing on genetic diseases to their children, by carrying out pre-implantation genetic diagnosis of IVF embryos.

"Families appreciate the opportunity to help develop treatments for a genetic disease in their families," Professor Jansen said.

The short-term aim of the cloning research was to produce disease-specific stem cells from patients that could be used to test for new drugs.

Longer term, therapeutic cloning would be the only way to produce new tissue that was perfectly matched to a patient, he said.

Last year, Japanese researchers developed a new way of producing embryonic-like stem cells, called induced pluripotent stem cells, by simply adding four genes to a cell from a patient.

Dr van Gend said this negated any argument for carrying out therapeutic cloning.

But Andrew Laslett, of the Australian Stem Cell Centre, said it was not yet clear which type of stem cell would lead to new therapies.

Although the induced pluripotent stem cells were ethically uncontroversial, there were safety concerns because viruses were used to add the genes.

"The jury definitely is still out," Dr Laslett said.

If Sydney IVF succeeds in obtaining stem cells from cloned embryos, their properties will be compared with those of induced pluripotent stem cells imported from the United States in a $550,000 research project funded by the NSW and Victorian governments.