British Association for the Advancement of Science festival:A UK scientist wants to modify pig genes to grow organs for transplantation into humans, writes Dick Ahlstrom, Science Editor, in York
The ability to create genetically modified animals is of fundamental importance to the future of human and animal health, says a controversial expert on human fertility. It also outstrips in importance the mapping of the human genome, according to scientist, author and professor, Lord Robert Winston.
"The ability to create [ transgenic animals] is infinitely more important than the mapping of the human genome," Lord Winston stated yesterday at the BA Festival of Science, under way in York. "I believe it is fundamentally a very, very important technology."
Lord Winston addressed a session entitled: Altering the genome of large animals.
Based at Imperial College London, he described his own experiments on mice and pigs where he is attempting to add genes to animal sperm cells as a way to permanently alter their genetic makeup.
The goal, he said was to be able modify animals, particularly the pig, to make organs such as heart and liver suitable for transplantation into humans.
These studies would greatly support improved animal health but would also provide "humanised organs" for transplantation, thus overcoming the severe shortage of human organs for transplants, he stated.
His experiments on what are known as germline cells, including sperm, is controversial in that it introduces genetic changes in an animal before it is born and subsequent offspring would also carry these genetic alterations.
For this reason regulatory authorities have been very slow to permit germline experiments if these animals are to be bred.
He said he had already successfully modified mouse sperm and had subsequently bred these "transgenic" mice. He also modified sperm in six "minipigs", a species of small pig weighing about 140kg, but his request to breed these animals was blocked by authorities earlier this year.
It was very complex science but the current difficulty related to regulation, he said. "There are numerous problems and one of them is the British regulating framework." He said that an EU directive actually blocked the pig experiments. "That is very disappointing," he stated, adding that he was considering moving the experiment to an animal research centre in the US state of Missouri. He had also applied to the US National Institutes of Health for funding to support the work.
Cloning served as a way to modify an animal, but it could not pass on the change to its offspring. Producing transgenic animals would allow a change to appear in subsequent generations. "The gene is not the only mode of inheritance," Lord Winston stated.
The ultimate goal was to produce a transgenic pig where genes are added to make its organs more like human organs. It would not affect structure, but would change the surface of cells so that once transplanted the organ would not be attacked and rejected by the immune system.
Immune rejection is the single greatest hurdle to human or animal transplantation.
He defended the use of animals in this way, saying that if it was ethical to raise animals as a source of food, it was "ethical to save lives" by making transgenic animal organs for transplant.
Suitable transplant organs would then be readily available.
"The ability to make a large animal transgenic is very close," he said, and could be here within two years. However, it would take much more research before the desired traits could be introduced and organs become available for use in humans.