Dolly team halts pig organ scheme

The scientists have cloned sheep

Health fears have forced the scientists who created Dolly the sheep to halt their new scheme to transplant pig organs into humans.

The group, based at the Roslin Institute in Edinburgh, had been using genetically modified pigs to create organs that might be used to make up the huge shortfall that exists in suitable human donor tissue.

But Geron Bio-Med, which has been paying for the experiments, has expressed concerns that new diseases could be passed on to humans from animals if so-called xenotransplants are carried out.

The California-based company, which resulted from the buy-out of the institute's commercial spin off Roslin Biomed, has now withdrawn its funding.

Professor Ian Wilmut, the leader of the team which created Dolly, said he was "disappointed" by the move.

Reduced optimism

He and other Roslin Institute scientists have been attempting to "switch off" specific pig genes in order to make human recipients less likely to reject the animal organs following a transplant.

Roslin scientists were involved in the work to produce the first pig clones

Professor Wilmut said: "We are in the process of reducing pig work. It has not quite finished but it will be before long.

"There is a certain reduction in the optimism of how practical it will be to take animals and use them in this way.

"The decision is disappointing because this is something we have been working on for a couple of years and we are now going to lose support.

Unknown viruses

"I think the concern is mainly unknown viruses. That's the frightening thing. If you know what the disease is you know how to look for it.

"It's possible there could be viruses we don't know about that could be released into the human population.

"British scientists have looked to animals as a potential source of organs like hearts and kidney but if that source is not available then people will go on dying because that source isn't available to them.

"It doesn't follow that just because Geron Bio-Med has taken this decision that all other companies will make the same decision."

The development follows a breakthrough from another Roslin offshoot, PPL therapeutics, which produced the world's first pig clones.

The company has also developed a technique to insert stretches of DNA into specific sites in an animal's genome. This makes the genetic modification of animals much easier - an important step in devleoping animal-to-human donor tissue.