A group of scientists managed resume blood flow and function for a few hours of cells in the body of pigs that had died shortly before, according to a study published Wednesday.
In 2019, a team of researchers in the United States shocked the scientific community by managing to restore cell function in the brain of pigs a few hours after their decapitation.
In their latest research, published Wednesday in the journal Nature, the same scientists tried to extend this technique to the entire body of the animal.
They caused a heart attack in anesthetized pigs, stopping blood flow and depriving their cells of oxygen (without oxygen, mammalian cells die).
After an hour, the corpses were injected with a liquid containing the blood of pigs (taken while they were alive) and a synthetic form of hemoglobin, the protein that carries oxygen in red blood cells.
They also injected drugs that protect cells and prevent blood clots from forming.
The blood began to flow again and many cells began to function again, even in vital organs such as the heart, liver, and kidneys, for the next six hours.
death, a ‘reversible process‘?
“These cells were working hours later when they shouldn’t have been working. This demonstrates that it can stop the disappearance of cells”, Nenad Sestan, lead author of the study and a researcher at Yale University, told a news conference.
Under the microscope, it was difficult to tell a normal, healthy organ from a post-mortem treated organ, added study co-author David Andrijevic, also of Yale.
The team hopes that the technique, called OrganEx, can be used to “save organs” prolonging its function, he said.
This could save the lives of people waiting for a transplant.
According to Anders Sandberg of the University of Oxford, OrganEx could also enable new forms of surgery by giving “doctors more leeway.”
But the technique poses a series of medical, ethical and even philosophical questions.
It could, for example, “increase the risk that resuscitated people will not be able to come off life support,” warned Brendan Parent, a bioethicist at New York University Grossman School of Medicine, in a commentary published in parallel by Nature.
According to Sam Parnia, from the Department of Medicine at the same university, this “truly remarkable” study also shows that “death is a treatable and reversible biological process hours after”.
So much so that the medical definition of death may need to be updated, says Benjamin Curtis, an ethical philosopher at Nottingham Trent University in the UK.
Considering this study, many processes that we thought were irreversible would not be”, he told the AFP.
“And, based on the current medical definition of death, a person may not actually be dead for hours,” since some processes continue for a time beyond the cessation of bodily functions.
The discovery could also spark a debate about the ethics of these procedures, especially since almost all pigs performed powerful head and neck movements during the experimentaccording to Stephen Latham, one of the study’s authors.
“It was quite surprising for the people in the room”, he told reporters.
The origin of these movements remains unknown, but he assured that at no time was electrical activity recorded in the animals’ brains, which rules out the return to consciousness.
These head movements are, however, “of great concern,” said Benjamin Curtis, as recent neuroscientific research has suggested that “conscious experience can continue even when electrical activity in the brain cannot be measured.”
“Therefore, this technique may have caused suffering in pigs and could cause suffering in humans if used on them”, he added, calling for more investigation. (YO)