Pig research shakes up what we know about dying

With more research, the advanced 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 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 shouldn’t,” 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.

The scientific journal Nature published the study on Wednesday.

“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. This is well into the postmortem period,” 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. Parnia was not involved in the investigation.

The images at the top represent the liver and kidneys, at the bottom.  The cells on the left have been subjected to control perfusion, while the images on the right represent the organs perfused with the OrganEx system described in the new study.  They show tissue integrity and that certain cellular functions have been restored.

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,” said study co-author Stephen Latham, director of the Yale Interdisciplinary Center for Bioethics, 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 one 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,” explains Latham out. “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’s much too early.”

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The research has the potential to lead to new treatment strategies for people who have had a heart attack or stroke, said Dr. Robert J. Porte of the University Medical Center Groningen, in the Netherlands, in an article published alongside the study.

“One might 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 ensure the safety of the system’s components.” specific clinical situations,” said Porte, who was not involved in the study.

However, Latham said such a possibility was “quite a long way off.”

“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 off. The much more promising potential short-term use is with organ preservation for transplant.”

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’s been relatively little studied, Sestan said.

“Within minutes of the heart stopping beating, there’s a whole cascade of biochemical events that are caused by 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 showed… is that this progression to massive permanent cell failure doesn’t happen so fast that it can’t be averted or possibly corrected.”

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