Pig-to-human transplant hopes rise

The pig research is being carried out by the same firm that created Dolly the sheep

LONDON, England -- The prospect of using pig organs in human transplants has moved a step closer.

Scientists in Scotland announced on Wednesday that they have produced five piglets genetically modified to provide organs for human patients.

PPL Therapeutics said it had produced five healthy "knock-out" piglets, born on Christmas Day.

They are so-called because a gene that causes the human immune system to reject pig organs within minutes of transplantation has been "knocked out" of their genetic make-up.

PPL, which was behind the cloning of Dolly the sheep, has found a way to inactivate the alpha 1,3 galactosyl transferase gene.

The piglets -- named Noel, Angel, Star, Joy and Mary -- were born at PPL's U.S. subsidiary in Virginia and the company said it thought they were the world's first cloned knock-out pigs.

QUICKVOTE Should pig organs ever be used in human transplants? Yes No View Results

Their birth is a major step towards successful xenotransplantation -- the transfer of cells or organs from one species to another, the firm said.

"With one of the major technical hurdles and scientific risks overcome, the promise of xenotransplantation is now a reality, with the potential to revolutionise the transplant industry," Alan Colman, PPL's research director, told the UK Press Association.

The technology could also be extended to include the potential transplant of cells to patients suffering from diseases such as Parkinson's, Alzheimer's and diabetes, PPL said.

Dr David Ayares, from PPL's U.S. division, described the development as a "critical milestone" in its research and said: "This advance provides a near term solution for overcoming the shortage of human organs for transplants as well as insulin-producing cells to cure diabetes."

'Limitless organ supply'

Doctors described the announcement as a significant step towards successful xenotransplantation.

Dr Andrew George, Reader in Molecular Immunology at Imperial College, London, told PA: "It is extremely significant because without knocking out the gene, pig organs would be destroyed by the human immune system while patients were still on the operating table.

"Xenotransplantation has a lot of possibilities for the treatment of patients with end stage organ failure. There are not enough organs out there for everybody who needs them.

"Obviously we would like to have a limitless organ supply and if pigs are bred for organs, we could effectively have a continual supply.

"Even if xenotransplantation never works, many of the technologies used could be applied to the treatment of other diseases."

Opponents of xenotransplantation said the development did not make the transfer of organs from pigs to humans any safer.

Dr Andre Menache, president of Doctors and Lawyers for Responsible Medicine, said xenotransplantation still presented a "Frankenstein scenario."

"There are about 600 genes responsible for tissue matching. You don't have to get all 600, but I would have thought you have to get quite a lot more than one right.

"I am by no means convinced. It belies common sense. The issue is a lot more complex than these people make it out to be," he said.

"We are opposed to xenotransplantation from a public health point of view, from a moral point of view and from an animal cruelty point of view.

"The strongest argument is still the threat of transmission of known and unknown viruses.

"It only needs one successful transmission of a disease-causing virus from an animal to man to start an epidemic. Viruses which are not dangerous in pigs can become dangerous in humans."

The British Union for the Abolition of Vivisection said clinical trials for xenotransplantation were still not a viable proposition.

Sarah Kite, BUAV's Research and Information Director, said: "Xenotransplantation research causes unacceptable suffering to sentient animals.

"Not only do we question the right to genetically engineer animals to use as spare-parts, we also believe that the science of xeno is so poorly developed that clinical trials cannot be reasonably be considered.

"In the meantime we should be doing all we can to improve the shortage of available human donor organs without resorting to animals."