With more research, the cutting-edge technique could one day potentially help preserve human organs for longer, allowing more people to receive transplants.
The researchers used a system they developed called OrganEx, which allows oxygen to recirculate the body of a dead pig, preserving cells and some organs after a cardiac arrest.
“These cells function hours after they shouldn’t,” said Dr. Nenad Sestan, the Harvey and Kate Cushing Professor of Neurology and Yale Professor of Comparative Medicine, Genetics and Psychiatry, who led the study.
“And what that tells us is that cell death can be stopped. And their functionality restored in many vital organs. Not even an hour after death,” he told a news briefing.
The scientific journal Nature published the study on Wednesday.
“This is truly remarkable and incredibly significant research. It demonstrated that after death, cells in mammalian organs (including humans), such as the brain, do not die for many hours. It’s well into the postmortem period,” Dr. Sam Parnia, associate professor of critical care medicine and director of the Critical Care and Resuscitation Study at New York University’s Grossman School of Medicine, told the Science Media Center in London. Parnia was not involved in the study.
The OrganEx system pumps a fluid called perfusate mixed with blood through the blood vessels of the dead pigs. The perfusate contains a synthetic form of the protein hemoglobin and several other compounds and molecules that help protect cells and prevent blood clots. Six hours after treatment with OrganEx, the team found that certain 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.
It builds on research published by the same team in 2019 that used a similar experimental system, called BrainEx, that delivered artificial blood to the brains of pigs, preventing the deterioration of important neural functions.
How can the research be applied to humans?
Although the research is still extremely early and very experimental, the researchers said they hope their work in pigs can eventually be applied to humans, mainly in terms of developing ways to expand the window for transplants . The current supply of organs is extremely limited, with millions of people worldwide waiting for transplants.
“I think the technology holds great promise for our ability to preserve organs after they are removed from a donor,” co-author Stephen Latham, director of Yale’s Interdisciplinary Center for Bioethics, said at the briefing.
“You could take the organ from a deceased donor and connect it to the perfusion technology and maybe then be able to transport it over a long distance over a long period of time to get it to the recipient who needs it.”
The researchers made it clear that they were by no means bringing the pigs back to life, and more work needed to be done to find out whether the organs were suitable for transplant.
“We wouldn’t be able to say that this study shows that any of the organs in this pig are … ready to be transplanted into other animals, we don’t know if they’re all functioning, what we’re looking at is cellular and metabolic levels,” he explained Latham. “And we’re not close to being able to say, ‘Oh my God, we’ve restored life not only to this pig, but to any of the individual organs.’ We can’t say that yet. It’s still very early.”
The research has the potential to lead to new treatment strategies for people who have a heart attack or stroke, said Dr. Robert J. Porte of the University Medical Center Groningen, Netherlands, said in an article published alongside the study.
“One can imagine that the OrganEx system (or its components) could be used to treat such people in an emergency. It should be noted, however, that more research will first be needed to confirm the safety of the system’s components in specific clinical situations,” said Port, who was not involved in the research.
However, Latham said such a possibility was “quite remote”.
“This idea of hooking up (a) person who’s had an ischemic injury, you know, someone who’s drowned or had a heart attack, I think is pretty far-fetched. The much more promising short-term potential use here is in organ preservation for transplantation.”
The researchers used up to 100 pigs as part of the study, and the animals were under anesthesia when the heart attack was induced.
The research also helps scientists better understand the process of death, something that is relatively understudied, Sestan said.
“Within minutes after the heart stops beating, there is a whole cascade of biochemical events triggered by a lack of blood flow, which is ischemia. And what this leads to is that the oxygen and nutrients that the cells need to survive are cut off. And that starts to destroy the cells,” Sestan added.
“What we’ve shown … is that this progression to massive permanent cell failure that doesn’t happen so quickly that it can’t be prevented or possibly corrected.”
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