The pigs had been dead in the lab for an hour—their bodies had no blood circulation, their hearts were motionless, and their brain waves were flat. Then a team of scientists from Yale University pumped a special solution into the bodies of dead pigs using a device similar to a heart-lung machine.
What happened next adds questions to what science considers the wall between life and death. Although the pigs were by no means considered conscious, their seemingly dead cells came to life. Their hearts raced as the solution, which the scientists named OrganEx, circulated through their veins and arteries. The cells in their organs, including the heart, liver, kidneys and brain, functioned again, and the animals never stiffened like a typical dead pig.
Other pigs that died within an hour were treated with ECMO, a machine that pumps blood through their bodies. They became stiff, their organs were swollen and damaged, their blood vessels collapsed, and purple spots appeared on their backs where blood accumulated.
Group reported his results Wednesday in nature.
The researchers say their goal is to one day increase the supply of human organs for transplant, allowing doctors to obtain viable organs long after death. And, they say, they hope their technology can also be used to prevent serious damage to the heart after a devastating heart attack, or to the brain after a severe stroke.
But the results are just the first step, said Stephen Latham, a bioethicist at Yale University who worked closely with the group. He emphasized that this technology is “very far from being used in humans.”
A group led by Dr. Nenad Sestan, professor of neurology, comparative medicine, genetics, and psychiatry at the Yale School of Medicine, was stunned by its ability to revitalize cells.
“We didn’t know what to expect,” the doctor said. David Andrievich, also a neuroscientist at Yale University and one of the authors of the article. “Everything we recovered was incredible for us.”
Others not connected with the work were equally astonished.
“It’s incredible, just mind-blowing,” said Nita Farahani, a law professor at Duke University who studies the ethical, legal and social implications of new technologies.
And etc. Farahani added that the work raises questions about the definition of death.
“We assume that death is a thing, it is a state of being,” she said. “Are there reversible forms of death. Or not?”
The work began a few years ago when the group similar experiment with brains from dead pigs from the slaughterhouse. Four hours after the pigs died, the group poured in an OrganEx-like solution they called BrainEx and saw that Brain cells that should have been dead can be revived.
This made them wonder if they could revive the entire body, the doctor said. Zvonimir Vrselja, another member of the Yale University team.
The OrganEx solution contained nutrients, anti-inflammatory drugs, drugs to prevent cell death, nerve blockers—substances that inhibit neuronal activity and prevent any possibility of the pigs regaining consciousness—and artificial hemoglobin mixed with each animal’s own blood.
As they treated the dead pigs, investigators took precautions to ensure the animals were not harmed. The pigs were anesthetized by cardiac arrest before death, and deep anesthesia was continued throughout the experiment. In addition, the nerve blockers in the OrganEx solution stop nerve firing to ensure that the brain is not active. The researchers also cooled the animals to slow down chemical reactions. Individual brain cells were alive, but there was no evidence of any organized global neural activity in the brain.
There was one startling discovery: OrganEx-treated pigs twitched their heads as the researchers injected the iodine contrast solution for imaging. Dr. Latham stressed that while the cause of the movement is unknown, there is no evidence of brain involvement.
Yale University has applied for a patent for this technology. Next step, Dr. Sestan said that it would be necessary to see if the organs were functioning properly and could be successfully transplanted. Over time, the researchers hope to test whether this method can repair a damaged heart or brain.
The journal Nature asked two independent experts to write comments on the study. One, Dr. Robert Porte, a transplant surgeon at the University of Groningen in the Netherlands, discussed the possible use of the system to expand the pool of organs available for transplantation.
In a telephone interview, he explained that OrganEx could in the future be used in situations where patients are not brain dead, but brain damaged to the point where life support is useless.
In most countries Dr. Porte said there is a five-minute “no touch” policy after the respirator is turned off and before the organs are harvested by transplant surgeons. But, he says, “there will be additional minutes before you rush into the operating room,” by which time the organs may be so damaged that they become unusable.
And sometimes patients don’t die immediately after life support is cut off, but their hearts are beating too weakly for their organs to remain healthy.
“In most countries, transplant teams wait two hours” for patients to die, the doctor says. Porte said. Then, he says, if the patient isn’t already dead, they don’t try to harvest the organs.
As a result, 50 to 60 percent of patients who died after the end of life support and whose families wanted to donate their organs could not be donors.
If OrganEx can restore these organs, Dr. The effect “would be huge” – a rapid increase in the number of organs available for transplants, Porte said.
other comments was with Brendan Parent, a lawyer and ethicist who is director of transplant ethics and policy studies at New York University’s Grossman School of Medicine.
In a phone interview, he discussed what he called “the tricky questions about life and death” that OrganEx raises.
“According to the generally accepted medical and legal definition of death, these pigs were dead. The parent said. But, he added, “the big question is: what function and what function will make a difference?”
Would the pigs still be dead if the group hadn’t used nerve blockers in their solution and their brains were functioning again? This would create ethical issues if the goal was to preserve organs for transplantation and the pigs were to some extent conscious during the process.
But restoring brain function may be the goal if the patient has had a severe stroke or drowned.
“If we are going to take this technology to the point where it can help people, we will need to see what happens in the brain without nerve blockers,” he said. The parent said.
In his opinion, the method will eventually have to be tested on people who may benefit, such as victims of a stroke or drowning. But this would require much thought on the part of ethicists, neuroscientists, and neuroscientists.
“How we get there will be the critical question,” Parent said. “When does the data we have justify this jump?
Another issue is related to the implications that OrganEx can have on the definition of death.
If OrganEx continues to show that the length of time after deprivation of blood and oxygen to which cells cannot recover is much longer than previously thought, then there must be a change in the time when a person is determined to be dead.
“It’s strange, but no different from what we went through in developing the ventilator,” Parent said.
“There is a whole population of people who in another era could be called dead,” he said.