Pig research challenges our knowledge of death

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 recirculates oxygen through the body of a dead pig, preserving cells and certain organs after cardiac arrest.

“These cells are functioning hours later than they should be,” said Dr. Nenad Sestan, 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 disappearance of cells can be stopped. And their functionality restored in several vital organs. Even an hour after death,” he said during a press briefing. .

The scientific journal Nature published the research on Wednesday.

“This is a truly remarkable and incredibly significant study. It demonstrates that after death, cells in mammalian (including human) organs such as the brain do not die for many hours. well into the post-mortem period,” Dr. Sam Parnia, associate professor of critical care medicine and director of critical care and resuscitation research at NYU Grossman School of Medicine, told Science Media Center from London. Parnia did not participate in the research.

The upper images represent the liver and kidneys, the lower ones.  The cells on the left were subjected to a control perfusion while the images on the right represent organs subjected to perfusion with the OrganEx system detailed in the new study.  They show the integrity of the tissues and that certain cellular functions have been restored.

The OrganEx system pumps a liquid called perfusate, mixed with blood, into the blood vessels of dead pigs. 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 certain organ functions had been 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 breakdown of important neural functions.

How could the research be applied to humans?

Although the research is still at an extremely early and highly experimental stage, the researchers said they hope their work in pigs may eventually be applied to humans, primarily in terms of developing ways to extend the window of transplants. The current organ supply is extremely limited, with millions of people around the world waiting for transplants.

“I think the technology holds great promise for our ability to preserve organs after they are removed from a donor,” said 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 infusion technology, and then maybe be able to transport it long distances over a long period of time to get it to a recipient who has it. need.”

The researchers clarified that they were in no way bringing the pigs back to life and that more work would need to be done to understand if the organs were suitable for transplants.

“We couldn’t say that this study showed that any of the organs in this pig were…ready to be transplanted into another animal, we don’t know if they all work, what we’re looking at is at the cellular and metabolic levels,” Latham explained. “And we’re a long way from being able to say, ‘Oh my God, we’ve brought back to life not just this pig, but all of the individual organs. We can’t say that yet. . It’s still way 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 in Groningen, the Netherlands, in an article published alongside the study.

“One would imagine that the OrganEx system (or its components) could be used to treat such people in an emergency. It should be noted, however, that further research will first be needed to confirm the safety of the components of the system in specific clinical situations,” said Porte, who was not involved in the research.

However, Latham said such a possibility was “pretty 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 that’s pretty far. The potential short-term use far more promising here is with the preservation of organs for transplantation.”

The researchers used up to 100 pigs in the study, and the animals were under anesthesia when the heart attack was induced.

The research also helps scientists better understand the dying process — something that’s relatively understudied, Sestan said.

“Within minutes of the heart stopping, there’s a whole cascade of biochemical events triggered by a lack of blood flow, which is ischemia. And what that leads (to) is that the “Oxygen and nutrients that cells need to survive are cut off. And it starts to destroy the cells,” Sestan added.

“What we showed… is that this progression to massive permanent cellular failure, which does not occur so rapidly that it cannot be prevented or possibly corrected. »

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