Scientists have managed to reactivate blood circulation and the functioning, for a few hours, of the cells of the body of pigs that died shortly before, according to a study published this Wednesday in the journal Nature. These results give hope for medical uses, but also raise ethical questions.
In 2019, a team of researchers based in the United States surprised the scientific community by successfully restoring cell function in the brains of pigs within hours of their decapitation. These same scientists are behind this latest research, in which they sought to extend this technique to the entire body of the animal.
“The disappearance of cells can be stopped”
They caused heart attacks in anesthetized pigs, stopping blood flow and depriving their cells of oxygen; without oxygen, mammalian cells die.
After an hour, they injected the carcasses with a liquid containing the pigs’ blood (taken from them alive) and a synthetic form of haemoglobin, the oxygen-carrying protein in red blood cells. As well as medications that protect cells and prevent the formation of blood clots.
The blood began to flow again, and many cells began to function again, including in vital organs like the heart, liver, and kidneys, over the next six hours.
“These cells were working hours later when they shouldn’t have been. This shows that you can stop the cells from disappearing,” said Nenad Sestan, lead author of the study and a researcher at Yale University.
Under a 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.
“Save organs” by prolonging their function
The team hopes that this technique, called OrganEx, could be used to “save organs” by prolonging their function, he explained. Which potentially saves the lives of people waiting for a transplant. OrganEx could also enable new forms of surgery by giving “more medical freedom,” according to Anders Sandberg of the University of Oxford.
But this technique raises a number of medical, ethical, and even philosophical questions. It could “increase the risk that resuscitated people may not be able to recover from a life-support state,” warned Brendan Parent, a bioethicist at New York University’s Grossman School of Medicine, in a commentary published in parallel by Nature.
For Sam Parnia, from the department of medicine at the same university, this “really remarkable” study also shows that “death is a biological process that can be treated and is reversible hours later.” 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.
“With this study, many processes that we thought were irreversible would not be,” he told AFP. “And, according to the current medical definition of death, a person might not actually be dead for hours,” with some processes continuing for a time beyond the cessation of bodily functions.
“It is possible that this technique caused suffering to the pigs”
This discovery could also spark a debate about the ethics of such procedures. Especially since almost all the pigs made powerful head and neck movements during the experiment, according to Stephen Latham, one of the study’s authors. “It was quite surprising to the people in the room,” he told reporters.
The origin of these movements is unknown, but he assured that at no time was electrical activity recorded in the brain of the animals, so a recovery of consciousness is excluded.
However, these head movements are “of great concern,” said Benjamin Curtis, because recent research in neuroscience has suggested that “conscious experience can continue even when electrical activity in the brain cannot be measured.”
“Therefore, it is possible that this technique caused suffering in pigs and could cause suffering in humans if used on them,” he added, calling for further investigation.
Source: BFM TV
