Scientists restored some pig brain functions hours after death
A team of researchers from the U.S.’s Yale University reported that they were able to partially “revive” the brains of pigs four hours after they died. Researchers have restored many of the brain’s basic cellular functions, which were previously thought to cease a few moments after death.
Researchers at Yale University in New Haven connected mozg pigs into the system, whichory pumped blood substitute. MoThe zgi were obtained from a nearby slaughterhouse about four hours after the animals died. The technique restoresosomeore key functions, such as the ability of the comorek for energy generation and waste disposaloin, and also helped maintain internal structures mozgu.
SpecificoThe phony experiment was published in the journal „Nature”.
Death of the comoThe system was created in the mozg is usually considered a rapid and irreversible process. In cut off from oxygen and blood supply mozg the electrical activity ceases and signs of consciousness disappear within seconds, while energy reserves are depleted within minutes.
From the beginning of the 20th century, scientists conducted experiments thatore were to maintain the moof bringing animals back to life after the heart has already stopped functioning. By cooling the mozgu and pumping blood or blood substitute for a while this was successful. But how did such a mozg is not clear. Other studies have shown that the comorki taken from mozgu long after death can function efficiently, if only to produce proteins. This led Nenad Sestan of Yale University to wonder if the entire mozg can be restoredoconed to life a few hours after death?
In his experiment, Sestan used 32 pig headsoIn obtained from a slaughterhouse located near his lab. WspoThe scientists working with him have drawn mozgi from the skulls and placed them in a special chamber. They then matched the organointo the system they developed and four hours after the animals died, they began pumping into the veins and arteries of the mozgoin a specially prepared chemical cocktail.
The system, whichory scientists called BrainEx, mimicking blood flow, delivering nutrients and oxygen to the comorec modeath. SolutionoThe preservative used by the team ofoł contained chemicals thatore were to protect the neurons from damage and prevent the possible onset of electrical activity mozgu. Nevertheless, the researchers monitored the electrical activity of the mozgu during the experiment and were willing to administer anesthetics if they saw signs of regaining consciousness.
After pumping the solution for six hours, the researchers noticed that neurons and other comorki mozg have resumed normal metabolic functions, such as sugar consumption and carbon dioxide production. They also observed that the immune system mozgu also resumed functioning, and when they applied electrical impulses to the prob tissues mozgoin they found that afterolne neurons can continue to conduct signals.
– The intact mozg of a large mammal retains a previously underestimated ability to restore theocation of circulation and certain molecular and comorkowych many hours after cardiac arrest,” said Sestan.
The researchers sustained pig mozg alive for 36 hours. The structures of someolnych comorek and parts of the mozgu were preserved. In mozgs from the control group, whichoWhen the brain is not given a solution rich in nutrients and oxygen, these structures have disintegrated.
However, the complexoł did not observe coordinated patterns ofoin electrical activity throughout the mozgu, which would indicate advanced m activityozgu, and even the awareness. Scientists say that the resumption of activity mozg may require electrocution or preservation of mozgu in solution for an extended period of time to allow the comorkom recovery from damage, whichorych suffered deprived of oxygen.
– In the experiments, we did not observe the type of organized electrical activity associated with perception, consciousness or awareness – said Zvonimir Vrselja, cooauthor of the publication. – By definition, it is not a living mozg, but it is comorkowo active mozg,” he added.
Experiments have reignited the debate on the very nature of death. In most of the countryoIn legislation mowi that the person is dead when m activity ceasesozgu or when the heart and lungs stop functioning. Research by scientistsow from Yale University showed that some activity moHowever, the syndrome can be broughtocic even after death, at least in mozgach of pigs. This challenges long-held assumptions about the timing and irreversible nature of the cessation of someohe functions of mozg after death.
– For most of human history, death was very simple. Now we have to ask again what is really irreversible,” said Christof Koch of the Allen Institute for Brain Science, who was not involved in the study.
But there are more questions. Developoj technologies with the potential to support disembodied organsow has broad ethical implications. – In fact, there is no surveillance mechanism, ktory moheads to control the possible ethical implications of creating consciousness in something that is not a living animal, said Stephen Latham, a bioethicist at Yale, whoory wspoHe worked with Sestan’s team. But he added that in someocases in which it may be ethically justified – for example, if it allows scientists to test a drugow on such organs, not on humans.
– We could imagine that such mozg may be capable of consciousness – theorized in turn by George Mashour, a neurologist at the University of Michigan, whoseory studies near-death experiences. – But it is very interesting to think about what consciousness would be like, in the absence of the organoin and peripheral stimulation, he added.
The research has raised roalso doubts whether damage to the mozgu and death are permanent and irreversible. Lance Becker, an emergency medicine specialist at the Feinstein Institute for Medical Research in Manhasset, acknowledged that many physicians assume that even minutes without oxygen can cause irreversible harm. However, experiments on pigs suggest that mozg may remain viable much longer than previously thought, even without external support. – This publication throws a grenade into the middle of what are common beliefs. We may have greatly underestimated the ability of the mozgu to regenerate,” assessed.