Scientists have restored blood circulation and other cellular functions in pigs an hour after their death using new technology that delivers cell-protective fluid to organs and tissues.
The findings were published on Wednesday in the journal Nature, can help extend the health of human organs during surgery and also make more transplants possible.
While the researchers, including those from the Yale School of Medicine in the US, found no electrical brain activity associated with normal brain function after the procedure, the research confounds conventional wisdom about life and death.
“This study shows that our social convention regarding death, ie as an absolute black-and-white ending, is not scientifically valid,” said Sam Parnia, director of critical care and resuscitation research at New York University Grossman School of Medicine.
“Scientifically speaking, death, on the other hand, is a biological process that remains treatable and reversible for hours after it has occurred,” said Dr Parina, who was not involved in the study.
Just minutes after the last heartbeat, blood circulation begins to stop and cells in the body begin to die due to lack of oxygen, and chemical changes that damage tissue and organ function begin.
However, the new study suggests that cascading cell failure on such a massive and permanent level does not happen so quickly.
“All cells don’t die immediately, it’s a more long-term series of events. It’s a process where you can intervene, stop and restore some cellular function,” said David Andrijevic, study leader at the Yale School of Medicine.
In the research, the researchers used a new technology consisting of a perfusion device similar to heart-lung machines – which does 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 pig. body.
They induced cardiac arrest in anesthetized pigs and treated them with the new technology, called OrganEx, an hour after death.
Researchers found that some key cellular functions were active in many areas of the pigs’ bodies, 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 retained the ability to contract, after treatment with the device.
“We were also able to restore whole-body circulation, which surprised us,” said Nenad Sestan, professor of comparative medicine, genetics and psychiatry at Yale and co-author of the study.
“Under the microscope, it was difficult to see 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.
Researchers said they were “particularly surprised” to observe involuntary and spontaneous muscle movements in the head and neck regions when evaluating the treated animals, indicating preservation of some motor functions.
However, researchers said further studies are needed to understand the restored motor functions.
They added that strict ethical review by other researchers and bioethicists is also required.
“This is a truly remarkable and incredibly important study. It shows that after death, cells in mammalian organs (including humans) such as the brain do not die for many hours. This is well into the post-mortem period,” said Dr Parnia.
While the research could lead to more lives saved via organ transplants each year, the professor of critical care medicine said the new method could also find use in preserving organs in those who have died but where the underlying cause of death can still be treated.
“Today this would include 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 allow time for doctors to fix the underlying condition (such as a blocked blood vessel in the heart that had led to a massive heart attack and death, or repair a torn blood vessel that had led to death from massive bleeding after trauma), restore organ function and bring such people back to life many hours after death,” added Dr Parnia.
Researchers say the findings also raise ethical questions about when a person can be definitively declared dead.
“There is a challenging ethical issue in deciding when radical life support is simply futile, and as technology advances we may find more ways to keep the body alive despite not being able to revive the person we actually care about,” Anders Sandberg, senior researcher at the Future of Humanity Institute, University of Oxford, said.
“Much work remains to find criteria for when further treatment is futile, and also for how to bring people back from the brink,” added Dr Sandberg, who was also not involved in the study.