Paris:
Scientists announced on Wednesday that they have restored blood flow and cell function in the bodies of pigs that had been dead for an hour, in a breakthrough, experts say this could mean updating the definition of death itself.
The discovery sparked hopes for a range of future medical applications in humans, the most immediate being that it could help organs last longer, potentially saving the lives of thousands of people around the world who need transplants.
However, it could also spark debate over the ethics of such procedures — especially after some of the apparently dead pigs startled scientists by making sudden head movements during the experiment.
The US-based team stunned the scientific community in 2019 by succeeding in restoring cell function in the brains of pigs hours after they were decapitated.
For the latest study, published in the journal Nature, the team sought to extend this technique to the whole body.
They caused a heart attack in the anesthetized pigs, which stopped the blood flowing through the bodies.
This robs the body’s cells of oxygen – and without oxygen, cells in mammals die.
The pigs then sat dead for an hour.
Destruction of cells can be stopped
The scientists then pumped the bodies with a fluid containing the pigs’ own blood, as well as a synthetic form of hemoglobin — the protein that carries oxygen in red blood cells — and drugs that protect cells and prevent blood clots.
The blood started circulating again and many cells started to function, including in vital organs such as the heart, liver and kidneys, during the next six hours of the experiment.
“These cells were functioning hours after they shouldn’t have been — what this tells us is that the demise of cells can be stopped,” Nenad Sestan, the study’s senior author and a researcher at Yale University, told reporters.
Co-lead author David Andrijevic, also of Yale, told AFP the team hopes the technique, called OrganEx, “can be used to save organs.”
OrganEx could also enable new forms of surgery, as it “creates more medical leeway in cases without circulation to fix things,” said Anders Sandberg of Oxford University’s Future of Humanity Institute.
The technique could also potentially be used to resuscitate people. However, this could increase the risk of bringing patients back to a point where they are unable to live without life support — caught on what’s been called the “bridge to nowhere,” said Brendan Parent, a bioethicist at NYU Grossman School of Medicine, said in a linked comment in Nature.
Would death be treatable?
Sam Parnia of the NYU Grossman School of Medicine said it was “a truly remarkable and incredibly important study.”
It showed that death was not black and white, but rather a “biological process that remains treatable and reversible for hours after it has occurred,” he said.
Benjamin Curtis, a philosopher focused on ethics at Nottingham Trent University in the United Kingdom, said the definition of death may need updating because it depends on the concept of irreversibility.
“This research shows that many processes that we thought were irreversible are in fact not irreversible, so according to the current medical definition of death, a person may not really be dead until their bodily functions have stopped,” he told AFP. .
“Indeed, there may be bodies in morgues right now that haven’t ‘died’ yet, if we consider the current definition to be valid.”
During the experiment, virtually all OrganEx pigs made vigorous head and neck movements, said Stephen Latham, a Yale ethicist and co-author of the study.
“It was quite shocking for the people in the room,” he told reporters.
He stressed that while it was not known what caused the movement, at no time was any electrical activity recorded in the pigs’ brains, showing that they never regained consciousness after death.
While there was a “small burst” on the EEG machine that measures brain activity at the time of the movement, Latham said it was likely caused by the head shifting that affected the recording.
However, Curtis said the movement was a “major concern” because recent neuroscience research has suggested that “conscious experience can continue even when electrical activity in the brain cannot be measured.”
“So it’s possible that this technique caused the pigs in question to suffer, and humans would suffer if it were used on them,” he added, calling for more research.
(Except for the headline, this story has not been edited by DailyExpertNews staff and has been published from a syndicated feed.)