The pigs had been dead for seven hours. But scientists noticed that their hearts, livers and kidneys still showed signs of life.
Within minutes of the final heartbeat, the lack of blood flow, oxygen and nutrients triggers a cascade of biochemical events that begin to destroy the body’s cells and organs.
So how were the pigs’ organs performing certain functions so long after their last breath?
Researchers at the Yale School of Medicine in the US used a new technology that provides a specially designed cell-protective fluid.
The cutting-edge technique meant they were able to restore blood circulation and other cellular functions in the pigs within an hour of death, with many functions observed up to seven hours later.
The findings could help extend the health of human organs during surgery and expand the availability of donated organs, said the authors of the study published in the journal Nature.
Read more: Genetically modified pig hearts transplanted into brain-dead humans
“All the cells don’t die right away, there’s a more prolonged series of events,” said David Andrijevic, a research associate in neuroscience at the Yale School of Medicine and co-lead author of the study.
“It’s a process where you can intervene, stop and restore some cellular function.”
In a study that may sound a bit like science fiction, cardiac arrest was induced in anesthetized pigs, which were treated with OrganEx one hour after death.
Six hours after the OrganEx treatment, the scientists found that certain important cellular functions were active in many areas of the pigs’ bodies – including the heart, liver and kidneys – and that some organ functions had been restored.
For example, they found evidence of electrical activity in the heart, which maintained its ability to contract.
“We were also able to restore circulation throughout the body, which surprised us,” said Nenad Sestan, professor of neuroscience and professor of comparative medicine, genetics and psychiatry at Harvey and Kate Cushing.
Normally, when the heart stops beating, the organs start to swell, collapsing blood vessels and blocking circulation, he said.
However, circulation was restored and organs from the deceased pigs that received OrganEx treatment appeared to be functional at the cellular and tissue level.
Read more: Scientists keep live brains of decapitated pigs to spark debate on ethics
“Under the microscope, it was difficult to tell the difference between a healthy organ and one that had been treated with OrganEx technology after death,” said Zvonimir Vrselja, research associate.
The researchers emphasized that further studies are needed to understand the apparently restored motor functions in animals, and that a rigorous ethical review from other scientists and bioethicists is needed.
The OrganEx technology could eventually have several potential applications, the authors said.
For example, it could prolong the life of organs in human patients and expand the availability of donor organs for transplantation.
It can also help treat organs or tissues damaged by ischemia during heart attacks or strokes.