Pig brains partially restored four hours after death

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US scientists partially restored pig brain four hours after slaughter of animals.

The findings could fuel debate on the barrier between life and death and provide a new avenue for research on diseases such as Alzheimer's disease.

The study showed that brain cell death could be stopped and even restored some connections in the brain.

However, there was no brain signal that would indicate an awareness or awareness.

Unexpected discoveries challenge the idea that the brain undergoes an irreversible decline a few minutes after the cessation of blood flow.

How was it done?

Thirty-two pork brains were taken from a slaughterhouse.

Four hours later, the organs were connected to a system created by the Yale University team.

He was pumping rhythmically (to mimic the pulse) a specially designed liquid around the brain, which contained synthetic blood to carry oxygen and drugs to slow or reverse the death of brain cells.

The brains of pork received the catering cocktail for six hours.

What did the study show?

Legend

The researchers found that synapses – connections between brains – worked

The study, published in the journal Nature, showed a reduction in cerebral cell death, restoration of blood vessels and some brain activity.

The researchers found functional synapses – the connections between brain cells that allow them to communicate.

The brains also showed a normal response to the drugs and consumed the same amount of oxygen as a normal brain.

It was every 10 hours after the decapitation of the pigs.

Especially in an electroencephalogram (EEG brain scan), the electrical activity at the brain scale did not signal an awareness or perception.

Basically, they were still dead brains.

What did we learn?

Research is transforming ideas about brain death, which many thought would have happened quickly and irreversibly without oxygen.

Professor Nenad Sestan, professor of neuroscience at Yale University, said, "Cell death in the brain occurs over a longer time window than we previously considered.

"What we show, the process of cell death is a gradual and progressive process.

"And that some of these processes can be either postponed, retained, or even reversed."

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Are these experiences ethical?

Pork brains came from the pig industry; the animals were not raised in a laboratory for this experiment.

But Yale's scientists were so afraid that pigs would be aware of giving drugs to the disembodied brain to reduce brain activity.

And the team was constantly monitoring the brains to see if there were any signs of higher brain function.

In this case, they would have used anesthetic and ended the experiment.

The ethicists, writing in Nature, believe that new guidelines are needed in this area, because animals used for research purposes could end up in a "gray area – not living, but not completely dead".

What purpose?

The immediate benefit of this work will be for scientists studying the brain in diseases such as Alzheimer's disease.

The organ is the most complex structure in the known universe, but techniques such as the freezing of brain slices or the growth of brain cell colonies in a satellite dish do not allow researchers to explore the full three-dimensional cabling. of the brain.

In the long run, scientists hope to find better ways to protect the brain after trauma such as a stroke or lack of oxygen at birth.

Dr. Andrea Beckel-Mitchener, Brain Initiative of the US National Institute for Mental Health, said, "This line of research could lead to a whole new way to study the post-mortem brain.

"It could also stimulate research to develop interventions that promote brain recovery after a loss of cerebral blood flow."

However, the researchers said it was still too early for the field to make a difference for patients after an injury.

Professor Sestan said, "We do not know yet whether we will be able to restore normal brain function."

Does this change the meaning of death?

For now, no, but some ethicists believe that we should have the debate now because people who are "brain dead" are a major source of organs to transplant.

Prof. Dominic Wilkinson, professor of medical ethics and neonatology consultant at Oxford, said: "Once a person has been diagnosed as" brain dead ", it is currently impossible for that person to heal.

"The human person that they were was gone forever.

"If, in the future, it was possible to restore the function of the brain after death, to bring back the mind and personality of someone, this would, of course, have important implications for our definitions of death. "

But this is not the case now.

Tara Spiers-Jones, Deputy Director of the Center for Discovery Brain Sciences at the University of Edinburgh, said: "This study is far from preserving the functioning of the human brain after death, as shown in the cartoon Futurama, where the heads were kept alive.

"It is rather a temporary preservation of some of the most basic cellular functions of the pork brain, and not the preservation of thought and personality."

Could the pig brain be aware of this?

In this experiment, the answer is clearly negative. The brains were actually silent.

But the research poses as many questions as she answers:

How long can researchers keep the brain in activity?
Would the results be even better if researchers did not wait four hours before starting?
In addition, the team used drugs to suppress brain activity – would decapitated brains be aware if they had not done so?

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