Harvesting organs from animals for human transplants 'Cruel'

By Kent Atkinson

February 2, 2005

A leading animal welfare lobbyist says it will strongly oppose any moves to allow xenotransplantation - the use of animal tissues in humans - not only because it is cruel to animals, but it may also endanger humans.

"All animals harbour viruses, and there is no better way to jump the species barrier than to implant animal organs into humans," said Save Animals From Exploitation (Safe) campaign director Hans Kriek.

The Aids pandemic began when the human immunodeficiency virus (HIV) which causes the illness crossed from monkeys into humans, he said.

Human T-cell lymphotropic virus (HTLV) which caused some forms of leukaemia, had similarly crossed the species barrier into humans.

"Xenotransplantation raises the stakes even further by increasing the danger of new, dreadful epidemics".

Mr Kriek was commenting on a discussion paper released yesterday by a government advisor on biotechnology, the Bioethics Council, which is consulting the public on xenotransplantation.

The report of the Royal Commission on Genetic Modification in 2001 led to a law change which required approval by the health minister for any animal-to-human transplant clinical trials, but that amendment is now set to expire in June.

The Bioethics Council has said the Government will have to take action on xenotransplants this year, and the Health Ministry is reported to want to ban animal-to human transplants completely, pending further research, because the animal organs may carry "retroviruses" - similar to HIV - into the human population.

Some retroviruses sit in the genetic material of their host, and can then be spread to sexual partners and their children. And even if the viruses are not active at the time they cross species, retroviruses can "switch on" later in the life of the new host, or that of their children.

But Mr Kriek said that xenotransplantation was not only a threat to human survival, but also to millions of animals in laboratories.

"Animal organs used for xenotransplantation are not by-products from the slaughterhouse but come from transgenic animals which suffer genetic engineering, cloning, reproductive manipulations, surgical operations and close confinement in unnatural indoor conditions," he said.

GE animals were subjected to many distressing and painful procedures: "Xenotransplantation is heavily promoted by biotech and pharmaceutical companies who would gain huge profits from breeding transgenic animals and selling anti-rejection and other drugs," he said.

The Bioethics Council said that non-human primates such as baboons and other monkeys were not a suitable source for xenotransplants because of their close genetic relationship to humans posed a risk of cross-species infections.

The US Food and Drug Administration has effectively prohibited the use of non-human primates in animal-to-human xenotransplantation since 1999.

Use of primates also raised serious ethical issues, as they had complex behavioural and social needs that were difficult to meet in a research laboratory.

But the council noted baboons were the most suitable species for animal-to-animal studies (such as pig-to-baboon) to obtain important information on the effectiveness of a procedure before it can be tested in an animal-to-human trial.

Pigs were considered to be the most likely and appropriate non-human source of organs and tissues - South Korea recently announced that it will spend $NZ83 million over the next 10 years to mass-produce genetically engineered pigs so their organs can be harvested for human transplants.

But animal-to-animal transplantation studies would use a variety of animal species in the early stages of the research (such as mice, rats and rabbits).

If these studies showed promising results, researchers would trial the procedure in an animal study in baboons, though fish and cattle might also be used for some procedures, such as helping to grow skin. Researchers were also considering the use of other species (such as cattle, fish and mice) for cellular transplants.

Researchers said that immune rejection of animal-to-human transplants could be avoided by genetically engineering source animals, inserting some human genes into the animals to make their cells, tissues and organs behave more like human-to-human transplants.

"This raises some difficult ethical issues about the rights and welfare of the animals, such as whether the insertion of human genes may make the animal in some way 'human', or whether inserted genes cause unexpected side-effects in the animals," the council said.

People who believe that human benefits outweigh the harm caused to animals often based their argument on the belief that humans have a moral status superior to that of animals, and that therefore the needs of humans outweigh the rights of animals.

Some people thought it was wrong to cause suffering to or kill animals even if this had major benefits, and others opposing the exploitation of animals said that the benefits to humans of xenotransplantation were often overstated and the suffering of animals understated.

Some types of xenotransplantation involve killing young pigs under anaesthesia, but others involve the destruction of a chimpanzee's immune system through chemotherapy and radiation.

Source animals for xenotransplantation would probably need to be bred and raised in isolation.

The Animal Welfare Act provided no guidance on balancing the harm to animals against the human benefits of the research. Weighing the interests of animals against those of humans could depend on the animal type - whether apes, pigs or mice - how much the animal suffered, and the benefits to humans.

The council said people with strong objections to genetic engineering might accept the transfer of an un-modified animal organ, but oppose the use of xenotransplantation if it involved genetic engineering of the donor animal.

Genetic engineering of pigs could "knock out" a gene that coats their organs with a sugar molecule, called a-1,3-galactosyltransferase or GGTA1, which triggered organ rejection when transplanted into humans.

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This article posted March 5, 2005.