Pig research halt 'a commercial decision'

Pigs are one potential solution to an organ shortage

A leading scientific institute is set to halt its research into pig organ transplantation - but says the decision is a "purely commercial" one.

Professor Grahame Bulfield, the director of the Roslin Institute in Edinburgh, UK, which is famous for creating Dolly the Sheep, stressed that scientists were not abandoning projects because of new health fears.

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

Professor Ian Wilmut, Roslin Institute

The pioneering team 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 discussions between scientists at Geron, the US-based company which is funding the work, and the Roslin Institute team are thought likely to lead to the research programme being halted.

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

Reduced optimism

He and other Roslin 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.

"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."

'Pragmatic decision'

Dr Bulfield said that although the decision had yet to be finalised, the feeling was that other centres might be better equipped to pursue xenotransplantation research than Roslin.

He said: "It is an entirely pragmatic decision - we are simply deciding where our strengths lie."

He denied that the team had uncovered any new evidence of health risks from xenotransplantation, as some newspapers reported on Monday. These risks involve the possibility of latent porcine viruses being activated in transplant patients.

The development follows a breakthrough from another Roslin offshoot, PPL therapeutics, which has 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. These developments make the genetic modification of animals for use in xenotransplantation much easier.

Potential solutions

Preventing the transmission of new, possibly devastating diseases into humans is one of the greatest obstacles to xenotransplantation.

Usually, it is very difficult for a virus which affects an animal to cross the "species barrier" and become a human virus.

But fears were heightened after a case in which an HIV patient given a baboon liver transplant was found to have a baboon virus.

The body which regulates xenotransplantation research in the UK has given a cautious go-ahead to pig organ transplantation provided safety concerns such as this have been fully addressed.

However, this has yet to happen. Fears about virus transmission are such that future regulation may require potential recipients to sign contracts undertaking not to have children - or even sex without barrier protection. Quite how this would be enforced is not entirely clear.

One potential solution put forward to the virus problem is to deliver the pigs by Caesarean section and then keep them isolated in a completely sterile environment for their entire lives to keep them free of natural pig infections.

But pigs are social animals, and ethical concerns have been raised about a practice that might limit their contact with other creatures.