ANIMAL TRANSPLANT PATIENTS 'WILL BECOME PART BEAST'
ACCORDING TO A JOINT REPORT BY THE British Union Against Vivisection AND Compassion in World Farming
Patients given animal transplant organs will eventually cease to be wholly human, the authors of a new report said today. They would become hybrids - part human part beast - as cells and proteins from pig or baboon organs spread around their bodies, it was claimed.
Until now the issue of "chimerism" - the mixing of features of different species - inherent in xenotransplants has been virtually ignored, according to the joint report from the British Union for the Abolition of Vivisection and Compassion in World Farming. The chimera was a mythical monster with a lion's body, goat's head and serpent's tail.
Scientists use the term to describe an animal or embryo combining the characteristics or more than one species.
Today's report, based on a review of research literature dating back to the early 1990s, said people given animal parts would effectively become chimeras as every tissue and organ in their bodies is colonised by non-human cells. Animal versions of protein factors, which play an important role in processes such as blood clotting and the transport of fatty acids, would also circulate round a patient's body.
Zoologist and neurochemist Dr Gill Langley, one of the authors, said today: "It's now clear that a human xenotransplant patient will become a literal chimera, a pig or baboon human hybrid. "Not only will an animal organ produce animal factors which will circulate around the blood stream, but cells from the animal organ will travel all over the human body and to every organ, including the heart, lungs, kidneys, bone marrow and lymph nodes." It may even be necessary for xenotransplant patients to become chimeras with a "dual-species immune system" to avoid long term rejection of the animal organ, she said.
A xenotransplant pioneer from Pittsburgh, USA, Dr Thomas Starzl, put baboon livers into two patients in the early 1990s. He coined the term "baboonisation" after finding that DNA from the primates had penetrated every tissue in their bodies.
Dr Langley, a consultant to the BUAV, said no attempt had been made to address the ethical issues surrounding chimerism which could have profound psychological and emotional as well as physical effects.
Another little known hazard of xenotransplantation was the long term risk of having an organ with a non-human biological structure, said the report. This could have serious and possibly fatal consequences even if the problem of organ rejection was overcome, it was claimed.
Blood-clotting factors from pig livers could theoretically cause life-threatening clots in humans, . Gas and blood pressures in an animal lung may not allow normal breathing in a human, and pig kidneys completely lacked an important transport mechanism which in humans helped control the excretion of some medicines including antibiotics.
A different version of the enzyme renin in pig kidneys could affect blood pressure and fluid balance, and a pig heart would probably be too weak to sustain circulation in a human, said the report.
The report also focused on the already well known dangers of pig viruses spreading to the human population. It said four new endogenous viruses had been identified in the past three years, three of which could infect human cells in the laboratory. The DNA of these viruses was embedded in the pig genes and could be passed onto offspring.
The report's authors called on the Government to impose an immediate moratorium on xenotransplantation research and said instead resources should be directed into improving the supply of human organs.
Mike Baker, chief executive of the BUAV, said: "We seem to be almost sleep-walking, oblivious to all the dangers, towards the use of a technology which causes animal suffering but which may be neither safe nor effective."
Imutran, the subsidiary of the giant Novartis group which is conducting xenotransplantation research with genetically engineered pigs, hopes to transplant pig kidneys into patients in about two years, assuming safety concerns are satisfied.
Dr David White, director of research at Imutran, said: "All transplant patients whether it be human to human or animal to human transplantation are chimeric. The definition is the mixture of tissue from two different people or animals.
"Well known transplant surgeon and pioneer, Dr Tom Starzl, has published many papers showing the benefit of microchimerism, when the immune cells of the donor lodge in the recipient and reduce the rejection response against the donor organ."
He added: "There is nothing new in the arguments put forward by these groups. The questions over safety have been raised by ourselves and others, including the Government..
"We began this work to save lives, not to endanger them, and as yet there is no reason to believe that xenotransplants from pigs to humans will cause any harm."
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