‘Zombie’ pigs raise ethical issues
The brains of dead pigs have been restarted by scientists in an experiment that raises serious ethical and philosophical questions about what it means to be alive and the prospect of bringing people back from the dead.
Researchers at Yale University pumped chemicals into the brains of 32 pigs that had been slaughtered in a nearby abattoir four hours earlier and their heads removed. Although the ‘‘zombie’’ animals never regained consciousness, many basic functions – including blood circulation – switched back on for 10 hours, ending assumptions that brain death was irreversible.
Experts have raised concerns that the tests may open the door for unscrupulous cryogenic companies to try to reanimate people who had their bodies frozen after death, or even retrieve memories or images from the brains of the dead.
There are also fears that the pigs did not regain consciousness only because the chemicals included drugs to limit the activity of brain cells.
Co-author Stephen Latham, director of Yale’s Interdisciplinary Centre for Bioethics, said: ‘‘I want to make clear that consciousness was never detected.’’
Dr Zvonimir Vrselja, the first author, added: ‘‘Clinically defined, this is not a living brain, but it is a cellularly active brain.’’
The death of brain cells and awareness was thought to be a swift process, occurring within seconds or minutes of oxygen and blood being cut off.
The Yale team used a machine called BrainEx, which pumped a solution mimicking oxygenated blood into the brain. It also included chemicals to protect nerve cells.
Nita Farahan, professor of law and philosophy at Duke University, said groups such as the Royal Society and Nuffield Council on Bioethics needed to set ethical principles for research.
‘‘It opens up possibilities that were previously unthinkable,’’ Farahan wrote in the journal
Nature. "Hundreds of people worldwide have already paid to have their brains frozen and stored, in the hope that scientists will one day be able to revive them. It’s easy to imagine misapplications of brain perfusion following the publication of the BrainEx study alone. Another question is what information, if any, could plausibly be retrieved from the brain.’’
The BrainEx therapy could one day help salvage brain function in stroke patients. Dominic Wilkinson, professor of medical ethics at the University of Oxford, said: ‘‘If, in the future, it was possible to restore the function of the brain after death, to bring back someone’s mind and personality, that would, of course, have important implications for our definitions of death.’’ –