They manage to "resuscitate" part of an animal's brain and a gap widens between life and death – 21/04/2019

In a study that raises profound questions about the demarcation line between life and death, researchers have restored some of the cell activity in brains extracted from slaughtered pigs.

Brains have not found anything that resembles consciousness: there was no signal indicating coordinated electrical signals, needed for higher functions such as consciousness or intelligence.

Although, as part of an experimental treatment, the blood vessels in the brains of pigs began to function as a blood substitute, and some brain cells regained metabolic activity, even in response to drugs. When the researchers evaluated the sections of brain tissue treated, they discovered electrical activity in some neurons.

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This work is very preliminary and has no immediate impact on the treatment of brain lesions in humans. Although the idea that parts of the brain can be retrieved after death, as conventionally defined, contradicts all that medical evidence believes about the organ and poses metaphysical enigmas.

"We had clear lines drawn between & # 39; This is alive & # 39; and & c & dquo; is dead & # 39; "Says Nita A. Farahany, bioethics specialist and law professor at Duke University." How do we now think of this "partially alive" enigma category? We did not think it could exist. "

For decades, doctors and family members in mourning have been wondering if it was possible to reinstate the duties of a person who has sustained prolonged brain injury as a result of a medical condition. a stroke or a heart attack. Were these brains really irrecoverable?

The new research confirms how little we know about the injured brain and so-called brain death. Bioethicists like Farahany were surprised and intrigued by the discoveries published in Nature.

"It's crazy," said Jonathan Moreno, a specialist in bioethics at the University of Pennsylvania. "If there was one issue that deserved a public debate on the ethics of science and medicine, it was this one."

Until now, it was badumed that the brain was deteriorating rapidly when the blood supply was interrupted. The cells deteriorate and the connections between the neurons collapse. Scientists believe that these changes are irreversible unless the blood is quickly restored.

Researchers at Yale University had the heads of 32 pigs slaughtered to obtain their meat. Scientists sawed the skulls and removed the brains. At the moment the experiment started, the brain They had no more blood and were at room temperature for four hours.

The team has developed a system called BrainEx that injects an experimental solution into the intact brain. Scientists hope that technology will help pave the way for new treatments for stroke, traumatic brain injury and diseases such as Alzheimer's disease.

The scientists injected the solution into the brains of the pigs for six hours. It brought oxygen to the tissues and contained chemicals that allowed scientists to track its flow with ultrasound.

The solution also contained chemicals to block the nerve signals. Scientists felt that brain cells could be better preserved and that their metabolisms would restart more quickly if they were not active.

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However, the researchers also did not want the brains to regain consciousness, as unlikely as it may seem. If the team saw an electrical activity suggesting a real awareness, she planned to administer anesthetic drugs to the brain and cool them immediately to stop the process.

In addition to the brains that received the BrainEx solution, the scientists examined brains that had not received infusions and those that received infusions of a dummy substance. The brains of both groups showed no signs of activity and their cells were deteriorating.

The National Institutes of Health, which supported the research, organized an information session to discuss its importance. "This is not a living brain, although it's an active cell brain," said Dr. Nenad Sestan, neuroscientist at Yale University, who led the tissue recovery research. "We wanted to check if certain functions of intact brain cells could be restored," he added. Some people who looked dead after prolonged exposure to the cold were resurrected and their brains continued to function, he observed. Patients with ACV who spent up to 16 hours with a clot blocking their blood to parts of the brain recovered their brain function once the doctors removed the clots.

"It's a real breakthrough," said Andrea Beckel-Mitchener, who leads the brain research efforts at NIH. "This has never been done before in the intact brain of a large mammal."

Christine Grady, head of bioethics at the NIH Clinical Center, said the work "presents, for the first time, an opportunity to study the entire brain of a mammal outside the body after death" . "This allows researchers to map cells and connections between them in a way that has never been possible before," he added. And the technique can expand the study of brain damage and cell repair, as well as how drugs affect the brain

Animal welfare

The ethical issues raised by research on resuscitated brain tissue are almost unprecedented. Among them are the questions about the welfare of laboratory animals.

"It's very new," said Stephen R. Latham, bioethics specialist at Yale. "This is not animal research.The brain reaches the researchers from a dead animal."

He asks how ethicists decide whether the suffering caused by research, to a "partially alive" brain, is justified by the objectives?

Although there is no electrical activity in the brains, it may be possible to restore it, said Farahany and other experts. It is unclear what would have happened if your solution did not contain nerve inhibitors.

When you have a cell-active brain, what are the appropriate protections, he asks. Is it treated like a living animal? He can not be treated like a dead animal, said Farahany. "What does it mean to talk about a pig's consciousness?" What are we looking for? "Moreno asked.

Implications in the donation of organs

In France and Spain, if a person has, for example, a heart attack that deprives them of blood reaching the brain, the emergency medical services staff tries to 30 minutes about to recover the cardiac activity, said Stuart Youngner, bioethicist at Case Western Reserve University, co-author of an editorial accompanying the study.

In the event of a failure, rescuers keep the organs in a portable cardiopulmonary device to pump the body; They also insert a balloon to prevent the blood from reaching the brain. In this way, the person can be an organ donor, since the brain is dead.

But "if something similar to BrainEx is available, why would not we do that instead of trying to preserve the organs?" Said Youngner.

In the United States, said Youngner, the ball system is considered unethical. But a system like BrainEx would probably encourage doctors and rescuers to try to resuscitate patients longer and harder. This could result in fewer patients with brain death and fewer organ donors.

The researchers confirmed that it would take years before brain resuscitation even reaches preliminary tests in humans. But, Farahany said he could imagine the day when brain resuscitation would become a standard medical practice. "Maybe we'll see this in our life," he said.

The New York Times. Special