Researchers at Yale University are challenging the idea of irreversible cardiac death after new technology tested on pigs restored some of the animals’ heart and brain cells an hour after dying.
Nature, a scientific journal, reported Wednesday that a team of scientists revived some circulation and cellular activity in the pigs’ vital organs by using a life-support type of system the group developed called OrganEx, which streams a mixture of pig blood and 13 compounds into a pig’s cardiovascular system and oxygenizes its tissue.
The experimental system evolved from technology developed in 2019 that delivered artificial blood to a pig’s brain called BrainEx.
“We made cells do something they weren’t able to do,” Zvonimir Vrselja, a neuroscientist and team member at Yale University, told the scientific journal. “We’re not saying it’s clinically relevant, but it’s moving in the right direction.”
While scientists kept the animals heavily sedated and hooked up to ventilators before and after dying from a cardiac arrest, they observed that the livers and kidneys of the pigs showed some functionality. The study also noted electrical activity and contractions in heart cells occurred.
“All cells do not die immediately,” David Andrijevic, an associate research scientist in neuroscience at Yale School of Medicine and co-lead author of the study, told the university. “There is a more protracted series of events.”
“It is a process in which you can intervene, stop, and restore some cellular function,” Andrijevic added.
During the six-hour experiment, the dead pigs began moving their head, neck, and torso involuntarily — which surprised researchers, who said the spinal cords may have controlled those motor functions.
“We can say that animals were not conscious during these moments, and we don’t have enough information to speculate why they moved,” said Dr. Nenad Sestan, a professor of neuroscience at the Yale School of Medicine and an author of the new research, according to NBC News.
Some of the brain tissue was preserved during the process. However, it did not show any coordinated activity, which could have indicated the animal regaining “consciousness or sentience.”
“If you can regain some function in a dead pig brain, you can do it in other organs, too,” Sestan said.
Researchers said it was difficult to tell the difference under a microscope between healthy organs and those treated using OrganEx.
Although the researchers have only just begun the experimental phase, the cellular restoration could potentially be replicated in humans, extending the lives of people who suffer from a stroke or a heart attack. The technology may even expand organ transplant availability.
“There are numerous potential applications of this exciting new technology,” Stephen Latham, director of the Yale Interdisciplinary Center for Bioethics, told the university. “However, we need to maintain careful oversight of all future studies, particularly any that include perfusion of the brain.”
Brendan Parent, an assistant professor of bioethics at the NYU Grossman School of Medicine, told NBC News his eyes “went wide” after reading about the new research.
“My brain went to all the crazy places we could go in 20 or 30 years,” Parent said.
The study further emphasized ethical challenges tied to using the technology and what it could mean to declare a person dead.
Arthur Caplan, a bioethicist at New York University, told Nature that as medicine evolves, the definitions of death may adapt.
“People tend to focus on brain death, but there’s not much consensus on when cardiac death occurs,” Caplan said. “This paper brings that home in an important way.”