Yale University researchers say they were able to restore blood circulation and other cellular functions in pigs a full hour after the animals were killed, suggesting cells didn’t die as quickly as scientists had believed.
With more research, the advanced technique may one day help preserve human organs for longer, allowing more people to receive transplants.
The researchers used a system they developed called OrganEx that allows oxygen to be recirculated through a dead pig’s body, preserving cells and some organs after cardiac arrest.
“These cells function for hours after they should not be,” said Dr. Nenad Sestan, the Harvey and Kate Cushing professor of neuroscience and professor of comparative medicine, genetics and psychiatry at Yale, who led the study.
“And what this tells us is that the destruction of cells can be stopped. And their functionality can be restored in multiple vital organs even an hour after death,” he told a news conference.
“This is a truly remarkable and incredibly important study. It shows that cells in mammalian organs (including humans) such as the brain do not die for many hours after death,” Dr. Sam Parnia, an associate professor of critical care medicine and director of critical care and resuscitation research at NYU Grossman School of Medicine, told the Science Media Center in London.
“This is well into the postmortem period.”
The OrganEx system pumps a liquid 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 the OrganEx treatment, the team found that certain key cellular functions were active in many parts of the pigs’ bodies, including the heart, liver and kidneys, and some organ function had been restored.
It builds on research published in 2019 by the same team that used a similar experimental system called BrainEx that delivered artificial blood to the pig brain, preventing degradation of key neural functions.
How could the research be applied to humans?
While the research is still at an extremely early stage and highly experimental, the researchers said they hoped their work in pigs could 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 have been removed from a donor,” study co-author Stephen Latham, director of the Yale Interdisciplinary Center for Bioethics, said during the briefing.
“You could take the organ from a deceased donor and hook it up to the perfusion technology, and then maybe be able to transport it over a long distance over a long period of time to get it to a recipient who needs it.”
The researchers made it clear that they were in no way bringing the pigs back to life and that more work would have to be done to understand if the organs were useful for transplants.
“We couldn’t say that this study showed that any of this pig’s organs … was ready for transplantation into other animals, we don’t know if all of them are functioning, what we’re looking at is at the cellular and metabolic levels,” Latham explains. .
“And we’re still a long way from being able to say, ‘Oh, my God, we’ve restored not only this pig, but each of its individual organs, to life.’ We can’t say that yet. It is still much too early.”
The research has the potential to lead to new treatment strategies for people with a heart attack or stroke, said Dr Robert J. Porte of the University Medical Center Groningen in the Netherlands, in a paper published alongside the study.
“You could imagine that the OrganEx system (or components thereof) could be used to treat such people in an emergency. Note, however, that more research will be needed first to confirm the safety of the system’s components in specific clinical situations,” said Porte, who was not involved in the study.
However, Latham said such a possibility was “quite remote.”
“This idea of hooking up (a) person who has had an ischemic injury, you know, someone who has drowned or had a heart attack, I think is pretty far off. The much more promising potential use in the near term is with 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 triggered.
The research also helps scientists better understand the process of death — something that has been relatively little studied, Sestan said.
“Within minutes of the heart stopping beating, there is a whole cascade of biochemical events caused by a lack of blood flow, which is ischemia. And what that leads to is that oxygen and nutrients that cells need to survive are stopped. And this is starting to destroy cells,” Sestan added.
“What we have shown… is that this progression to massive permanent cell failure is not happening so fast that it cannot be averted or possibly corrected.”