Kirk sounds note of caution over Chimera pig plans

The Church of Scotland has questioned the ethics of trying to grow human organs inside pigs.

A Pig
The human-pig chimeric embryos are being allowed to develop in the sows for 28 days before the pregnancies are terminated and the tissue removed for analysis.

The Kirk's Church and Society Council said there were many questions around whether it was right to inject human stem cells into pig embryos to produce human-pig embryos known as chimeras in a bid to overcome a worldwide shortage of transplant organs.

It added that that there were questions over whether using a sentient creature to act as a "factory for human organs" was acceptable.

Scientists at the University of California in the United States say the test subjects should look and behave like normal pigs except that one organ will be composed of human cells.

The human-pig chimeric embryos are being allowed to develop in the sows for 28 days before the pregnancies are terminated and the tissue removed for analysis.

Along with many others involved in bioethics, the Church of Scotland has expressed concern that a thorough understanding of the greater consequences of such technologies is necessary.

Wider implications

The Rev Dr Richard Frazer, convener of the Church and Society Council, said: "While we clearly wish to see technologies being used in ways which benefit all of humanity, we are concerned about some of the ethical questions which this technology raises.

"Perhaps most fundamental is the question as to whether it is right to mix human and animal embryonic material in this way.

"As far back as 2006, the General Assembly of the Church of Scotland was expressing concerns about the production of human/ animal chimeras.

"Until the moral and ethical implications have been adequately addressed, the Church remains concerned about the pursuit of scientific goals without due consideration of the wider implications of the potential consequences of this research."

Dr Murdo Macdonald, policy officer of the Kirk's Society, Religion and Technology (SRT) Project, said it is well known that a variety of approaches are being taken to try to tackle a transplant organ shortfall .

"For some time, scientists have also been working on inserting human genes into pigs, in order to produce so-called 'humanised pigs'," he added.

"The organs of these pigs wouldn't be recognised by our immune system as being foreign, thus reducing the risk of rejection following transplantation.

"What is now being proposed, however, is in a whole new league.

"Researchers want to take stem cells from humans, and to add these to the early embryo of a pig, to produce what is called a 'chimera'.

"In Greek mythology, the Chimera was an animal composed of parts from a number of different animals; when modern biologists talk about making chimeras, they mean something which is made by mixing the cells of early embryos from two different sources (this is slightly different from "hybrids", where the egg of one species is fertilised with the sperm of another species).

"Up until now, this area of work has mainly been using mice and pigs, which has been relatively uncontroversial.

"However, the suggestion to start mixing cells from early human embryos with cells from animal embryos has caused some controversy."

Human patient

Dr Macdonald said scientists had essentially developed pigs genetically engineered to not have a pancreas.

"In earlier experiments, they then added stem cells from another pig strain to the early embryo," he added.

"This is a chimera, formed from cells from two different pig strains.

"The novel twist now being proposed is to add human stem cells, rather than pig stem cells, to the pig embryo, to make a human/pig chimera, with the aim of getting a human pancreas to developing inside the piglets.

"This pancreas would, in theory, be available to transplant into a human patient."

Dr Macdonald said there were many ethical questions around the new technology.

"Perhaps most fundamentally is the question as to whether it is right to mix human and animal embryonic material in this way," he added.

"There are also questions around the ethics of using a sentient creature such as a pig to act as in effect a factory for human organs."

Difficult questions

Dr Macdonald said the question and other issues related to human embryo research, was considered at length in a SRT report to the Church of Scotland General Assembly in 2006.

He added that commissioners voted to oppose the creation of human/animal chimeras.

Dr Macdonald said: "Once again, science presents us with a dilemma which could be summed up by asking: just because we can do it, should we do it?

"The answer to that question is often difficult to discern but the question needs to be asked."

For further information please see www.srtp.org.uk; email mmacdonald@churchofscotland.org.uk.