According to a study that offers hope for medical applications but also raises ethical questions, scientists have managed to revive the blood flow and function of cells from the bodies of pigs that have just died for a few hours.
In 2019, a US-based team of researchers stunned the scientific community by successfully restoring cell function in the brains of pigs a few hours after they were decapitated.
In their latest research, published Wednesday in the journal Nature, the same scientists attempted to extend this technique to the animal’s entire body.
They caused heart attacks in anesthetized pigs, which stopped blood flow and deprived their cells of oxygen – without oxygen, mammalian cells die.
After an hour, they injected the corpses with a fluid containing the pigs’ blood (taken from the living) and a synthetic form of hemoglobin — the protein that carries oxygen in red blood cells. As well as drugs that protect cells and prevent blood clots from forming.
The blood began to flow again and many cells began to function again for the next six hours, including in vital organs such as the heart, liver and kidneys.
– Death, “reversible process”? –
“These cells worked hours later than they shouldn’t have. This shows that cell disappearance can be stopped,” said Nenad Sestan, lead author of the study and a researcher at Yale University.
Under the microscope, it is difficult to distinguish a normal, healthy organ from a postmortem treated organ, added David Andrijevic, co-author of the study, also from Yale.
The team hopes this technique, called OrganEx, can be used to “save organs” by prolonging their function, he explained. Which can potentially save the lives of people awaiting transplants.
According to Anders Sandberg from the University of Oxford, OrganEx could also enable new forms of surgery by giving “more medical leeway”.
But this technique raises a number of medical, ethical, and even philosophical questions.
It could “increase the risk that resuscitated people will then be unable to recover from a state of life support,” warned Brendan Parent, a bioethicist at New York University’s Grossman School of Medicine, in a parallel published commentary by nature.
For Sam Parnia of the same university’s medical school, this “really remarkable” study also shows that “death is a biological process that can be treated and is reversible hours later”.
– “Main concern” –
So much so that the medical definition of death may need updating, said Benjamin Curtis, a philosopher specializing in ethics at Britain’s Nottingham Trent University.
“In light of this study, many processes that we thought were irreversible would not be irreversible,” he told AFP. “And under the current medical definition of death, a person may not actually be dead for hours,” with some processes continuing beyond the cessation of bodily functions.
This discovery could also spark debate about the ethics of such procedures.
According to Stephen Latham, one of the authors of the study, almost all of the pigs made vigorous head and neck movements during the experiment. “It was quite surprising to people in the room,” he told reporters.
The origin of these movements remains unknown, but he asserted that at no time was electrical activity recorded in the animals’ brains, which rules out a recovery of consciousness.
These head movements are still “a big problem,” said Benjamin Curtis, because recent research in neuroscience suggests that “conscious experiences can continue even when electrical activity in the brain cannot be measured.”
“Therefore, it is possible that this technique causes suffering to pigs and could cause suffering to humans when applied to them,” he added, calling for more research.
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