Yale neuroscientists restored some cellular function, heart rhythm 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 could one day help reverse death.
In a feat that blurs the line between life and death, researchers at the Yale School of Medicine have restored some cellular function in the organs of dead pigs. The achievement, published in Nature on Wednesday, ignites hope for future medical breakthroughs that could save thousands of lives.
An 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, restoring full blood circulation to the pigs’ bodies. There was no evidence of electrical activity in the brain. Still, the researchers say they have uncovered a previously unknown capacity for mammalian cells to recover after the blood has stopped flowing.
“Cells are actually not dying as quickly as we assumed they do, which basically opens up the possibility of intervention,” Zvonimir Vrselja, a neuroscientist on the research team at Yale, said in a press briefing. “If they intervene in the right way, we might be able to tell them not to die.”
Unlocking this ability could allow clinicians to preserve more human organs for donation after death, reducing the shortage of transplant organs and saving thousands of lives. The new technology could also revolutionize life-sustaining 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 been given an additional tool to push it,” Anders Sandberg, a neuroscientist at the University of Oxford Future of Humanity Institute, who was not affiliated with the study, said in a statement.
The same research group previously developed a perfusion system called BrainEx. In 2019, the system restored some structure and function in the brains of dead pigs four hours after they were 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 heart failure, according to Dr. Sam Parnia, director of critical care and resuscitation research at New York University Grossman School of Medicine. which was not associated with the new study.
With organ tissue preserved and cell death delayed, doctors would have time to unblock the artery that caused the heart attack, or repair the ruptured vessel that caused the patient to bleed out.
“Otherwise, healthy people, including athletes who die but where the cause of death is treatable at any given time, can potentially be brought back to life. And if the cause of death is untreatable, their organs can be preserved to give life to thousands of people every year,” said Parnia 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 from use in humans,” Dr. David Andrijevic, a neuroscientist on the research team at Yale, said in the briefing, adding, “It does not restore all function in all organs.”
Better organ preservation can save thousands of lives
Normally, when a heart stops beating and blood stops flowing, it causes other organs to swell. The blood vessels collapse and prevent new blood flow.
By preventing swelling and restoring full circulation, the new OrganEx technology may one day expand the window for saving organs from healthy people who have died. It will enable more organ donations, potentially saving thousands of people who would otherwise die on transplant waiting lists.
This newfound capacity to restore organ cell function may also lead 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 cell death, 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 completely flushed with blood and fully oxygenated, with minor bleeding and inflammation. The researchers even observed patterns of gene expression in certain cells that indicated the tissues were repairing themselves.
These potential new capabilities — preserving more organs for transplant, making life support more effective and reviving people whose blood has stopped flowing — require much more research. They also have ethical implications.
“There is a challenging ethical problem in deciding when radical life support is just futile, and as technology advances we can find more ways to keep the body alive, despite not being able to revive the person we actually We care about. Much work remains to be done to find criteria for when further treatment is useless, and also in how to bring people back from the brink, said Sandberg.
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