A farmer outside Paige, Texas, hosing down pigs to cool them in July. Photo: Sergio Flores/Bloomberg via Getty Images
Researchers at Yale University recently used an experimental system to restore the cells and some function to vital organs of pigs an hour after the animals died, according to a new preliminary study published in the journal Nature on Wednesday.
The big picture: The study's results confront the idea of irreversible death and raise philosophical and ethical questions about our definition of death.
Why it matters: The resuscitation system could one day help preserve organs for transplantation, though it does not yet have any practical clinical relevance, the researchers found, per Nature.
- This follows a 2019 study by the same researchers in which the disembodied brains of pigs were revived and kept alive several hours after the animals were slaughtered through the use of a similar experimental system.
How it works: The pigs, which were sourced from a local farm, were sedated before researchers stopped their hearts, thus stopping blood flow to and setting off cellular decomposition within their vital organs.
- One hour after the pigs died, a control group of pigs were hooked up to a extracorporeal membrane oxygenation machine or were given no treatment, while another group were attached to the new system, called OrganEx, which is a blood substitute that's pumped through the animal's cardiovascular system.
- The substitute is a fusion of the animal's blood and 13 medical compounds — including anticoagulants, immunosuppressants, anesthetics and neuronal blockers — that researchers hypothesized would slow decomposition and restore organ function.
The intrigue: Although, in the pigs that received OrganEx, the researchers did not observe coordinated electrical activity in the brain — which would be evidence of consciousness — they did see "preserved tissue integrity, decreased cell death and restored selected molecular and cellular processes across multiple vital organs" in those animals.
- This included electrical activity and contraction of their hearts, though the cardiac organs never fully restarted. They also found evidence of gene expression patterns associated with cellular repair processes and the restoration of cellular metabolism.
- After the OrganEx application was completed, the pigs experienced involuntarily movements, like jerking of the head and torso, while the scientists were injecting a contrast dye to help define the animals’ brain for observation.
- The researchers attributed this movement to electrical activity in the spinal cord and not the brain.
What they're saying: “We made cells do something they weren’t able to do” after the animal was technically dead, Zvonimir Vrselja, a neuroscientist at Yale University and a member of the research team told Nature.
- “We’re not saying it’s clinically relevant, but it’s moving in the right direction," Vrselja said of the study.
- The study "reveals an underappreciated potential for cellular recovery after prolonged" death in a large mammal, the abstract reads.
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