Scientists restored blood circulation and other cellular functions in pigs an hour after their death using a new technology that delivers protective cell fluid to organs and tissues.
The findings, published Wednesday in the journal Nature, could help prolong the health of human organs during surgery and also make more transplants possible.
While scientists, including those at the Yale School of Medicine in the US, have not found any electrical brain activity associated with normal brain function after the procedure, the research confounds conventional wisdom about life and death.
“This study demonstrates that our societal convention regarding death, namely as an absolute black and white end, is not scientifically valid,” said Sam Parnia, director of critical care and resuscitation research at the Grossman School of Medicine at the University of New York.
“On the other hand, scientifically, death is a biological process that remains treatable and reversible for hours after it occurs,” said Parina, who was not involved in the study.
Just a few minutes after the final heartbeat, blood circulation begins to stop and cells in the body begin to die from lack of oxygen, and chemical changes begin that impair tissue and organ function.
However, the new study suggests that cascading cellular failure on such a large and permanent level does not happen so quickly.
“All the cells don’t die immediately, there is a more prolonged series of events. It’s a process where you can intervene and stop and restore some cellular function,” said David Andrijevic, co-author of the study at the Yale School of Medicine.
In the research, the scientists applied a new technology consisting of a perfusion device similar to heart-lung machines – which do the work of the heart and lungs during surgery – and an experimental fluid containing compounds that can promote cellular health and suppress inflammation throughout the swine. body.
They induced cardiac arrest in anesthetized pigs and treated them with the new technology, called OrganEx, an hour after death.
The researchers found that some important cell functions were active in many areas of the pigs’ body, including the heart, liver and kidneys, and that some organ functions were restored six hours after treatment with OrganEx.
The study also found evidence of electrical activity in the heart, which maintained its ability to contract, after treatment with the device.
“We were also able to restore circulation throughout the body, which surprised us,” said Nenad Sestan, a professor of comparative medicine, genetics and psychiatry at Yale and co-author of the study.
“Under the microscope, it was difficult to tell the difference between a healthy organ and one that had been treated with OrganEx technology after death,” added Zvonimir Vrselja, another author of the study.
The scientists said they were “especially surprised” to see involuntary and spontaneous muscle movements in the head and neck region when they evaluated the treated animals, indicating the preservation of some motor functions.
However, the researchers said additional studies are needed to understand restored motor functions.
They added that a rigorous ethical review from other scientists and bioethicists is also needed.
“This is a truly remarkable and incredibly significant study. It demonstrates that after death, cells in mammalian (including human) organs, such as the brain, do not die for many hours. This is well into the post-mortem period,” said Dr. parnia.
While research could lead to more lives saved through organ transplants each year, the professor of critical care medicine said the new method could also be used to preserve organs in those who have died but in whom the underlying cause of death remains treatable. .
“Today, this includes athletes who die suddenly from a heart defect, people who die from drowning, heart attacks, or massive bleeding after trauma (such as car accidents),” he explained.
“This will give doctors time to correct the underlying condition (such as a blocked blood vessel in the heart that led to a massive heart attack and death, or repair a torn blood vessel that led to death from massive bleeding after trauma), restore function organ and bring these people back to life many hours after death,” added Dr. parnia.
The researchers say the findings also raise ethical questions about when a person can be conclusively declared dead.
“There is a challenging ethical issue in determining when radical life support is useless, and as technology advances, we may find more ways to keep bodies alive despite being unable to revive the person we truly care about.” Anders Sandberg, a senior fellow at the Future of Humanity Institute at the University of Oxford, said.
“A lot of work remains to find criteria for when further treatment is futile and also on how to bring people back to the brink,” added Sandberg, who was also not involved in the study.