Yale neuroscientists restored some cellular function, heartbeat, and blood flow in dead pigs, they said Wednesday.
The discovery shows that intervention can stop cells from dying and preserve organs after death.
The new technology could lead to more organs for transplant, and may someday help reverse death.
In a feat that blurs the boundary between life and death, researchers at the Yale School of Medicine have restored some cell functions in the organs of dead pigs. The achievement, which was published in Nature on Wednesday, ignites hopes for future medical breakthroughs that could save thousands of lives.
One hour after death, researchers connected pigs to a system of pumps, heaters, and fillers called OrganEx. By artificially flushing the pigs’ organs with blood — a process called perfusion — they restored molecular and cellular function in the heart, brain, liver and kidneys.
The hearts even contracted to pump blood, indicating renewed electrical activity, and restored full blood circulation in the pigs’ bodies. There was no sign of electrical activity in the brain. Still, the scientists say they’ve uncovered a previously unknown capacity for mammalian cells to recover after blood has stopped flowing.
“Cells actually don’t die as quickly as we assumed that they do, which basically opens up the possibility for intervention,” Zvonimir Vrselja, a neuroscientist on the research team at Yale, said in a press briefing. “If properly intervened, we can maybe tell them not to die.”
Unlocking that ability could allow clinicians to preserve more human organs for donation after death, reducing the transplant-organ shortage and saving thousands of lives. The new technology could also revolutionize life-support treatment. Some researchers said the discovery could even pave the way for bringing people back to life hours after death.
“Death is not an instantaneous event, but rather a gradual process, and we have gained a further tool to nudge it,” Anders Sandberg, a neuroscientist at the University of Oxford Future of Humanity Institute, who was unaffiliated with the study, said in a statement.
The same research group previously developed a perfusion system called BrainEx. In 2019, that system restored some structure and function in the brains of dead pigs four hours after they’d been decapitated.
Death is more reversible than scientists thought
The OrganEx process could one day save people who die from drowning, heart attacks, massive bleeding from car accidents, or athletes who die suddenly from a heart defect, according to Dr. Sam Parnia, director of critical care and resuscitation research at New York University Grossman School of Medicine, who was unaffiliated with the new study.
With the organ tissues preserved and cell death delayed, doctors would have time to unblock the artery that caused the heart attack, or repair the torn vessel that caused the patient to bleed out.
“Otherwise healthy people, including athletes who die, but in whom the cause of death is treatable at any given time, can potentially be brought back to life. And if the cause of death is not treatable, then their organs can be preserved to give lives to thousands of people every year,” Parnia said in a statement.
“Scientifically, death is a biological process that remains treatable and reversible for hours after it has occurred,” he added.
Still, the Yale researchers cautioned against getting too excited about life after death.
“This is very far away from use in humans,” Dr. David Andrijevic, a neuroscientist from the research team at Yale, said in the briefing, adding, “It doesn’t restore all function in all organs.”
Better organ preservation could save thousands of lives
Normally, when a heart stops beating and blood stops flowing, it causes other organs to swell. Blood vessels collapse and prevent new blood flow.
By preventing swelling and restoring full circulation, the new OrganEx technology could one day extend the window for salvaging organs from healthy people who have died. That would allow for more organ donations, potentially saving thousands of people who would otherwise die on transplant waitlists.
This newfound capacity for restoring organ cell function could also lead researchers to more effective life support.
To sustain patients whose heart or lungs have stopped working, hospitals use a technique called extracorporeal membrane oxygenation (ECMO) to flush blood through the dysfunctional organ, a process called perfusion. ECMO only slows the death of cells, and it often fails to fully saturate organs with blood, leaving some smaller blood vessels to collapse.
OrganEx is “like ECMO on steroids,” said Dr. Nenad Sestan of the Yale neuroscience team, and in the new study it performed much better than ECMO. The organs showed signs of being fully flushed with blood and fully oxygenated, with less hemorrhage and inflammation. The researchers even observed patterns of gene expression in certain cells that indicated the tissues were repairing themselves.
These potential new abilities — preserving more organs for transplant, making more effective life support, and reviving people whose blood has stopped flowing — require much more research. They carry ethical implications, too.
“There is a challenging ethical issue in determining when radical life support is just futile, and as technology advances we may find more ways of keeping bodies alive, despite being unable to revive the person we actually care about. Much work remains to find criteria for when further treatment is futile, and also in how to get people back from the brink,” Sandberg said.
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