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Researchers at the Yale School of Medicine in the United States have developed a system similar to a dialysis machine called BrainEx, which restores the flow and flow of oxygen in a brain without a brain.
Researchers did not kill animals for the purpose of the experiment but bought pork heads at a slaughterhouse. According to studies, from a technical point of view, pigs do not show signs of electrical neuronal activity necessary for consciousness.
"From a clinical point of view, we can not talk about living brains," says Nenad Sestan, neuroscientist at the Yale University School of Medicine, co-author of the published study. in Nature.
The new system allowed the brain to stay in better shape than the brain left to decompose naturally, thus restoring functions such as the ability to absorb glucose and oxygen for six hours. The researchers say that this technique could give a major boost to studies on the treatment of disorders and diseases of the brain in humans.
"We are very excited about this discovery and the BrainEx will help us better understand the treatment of people who have had a heart attack and have lost normal blood flow to the brain, which really improves our ability to study cells as they appear interconnected. in this way three-dimensional and complex, "adds Khara Ramos, director of the Neuro Program at the National Institute of Neurological Disorders and Stroke in the United States.
Ethical dilemmas
Nevertheless, the discovery opens considerable ethical questions, a debate that researchers are constantly addressing.
"This is an extraordinary and very promising discovery for neuroscience. It immediately provides a much better model for the study of the human brain, which is extremely important given the high number of human suffering caused by brain disorders. says Nita Farahany, a bioethicist at Duke University School of Law, quoted by National Geographic.
"This also causes a number of fundamental assumptions in neuroscience, such as the fact that a loss of oxygen to the brain results in irreversible death of the body," explained the investigator.
For millennia, people were considered dead when they stopped breathing and their hearts stopped beating. But the innovations of modern medicine are constantly revolutionizing the terms. The invention of mechanical fans has kept organisms alive and decades of improvements in cardiac surgery and transplantation mean that even a stopped heart would not necessarily mean the end.
Mammalian brains, comparable to the human brain, are high performance machines that require a constant flow of oxygen-rich blood. If the blood flow is interrupted, the man loses consciousness after only a few seconds. Within five minutes, deposits of vital brain molecules, such as glucose, are depleted.
The brain then enters a spiral of death that, until now, scientists have considered irreversible.
The more researchers understand these processes, the more the definition of death has evolved over time. In 1968, a committee of doctors at Harvard University formulated a reference definition of "irreversible coma", which we now call "brain death": total lack of responsiveness, inability to breathe without the help of Devices, complete absence of reflection, and signs of large-scale electrical activity in the brain. Today, the American Academy of Neurology maintains a checklist that clinicians use to qualify for brain death.
But there are signs of greater brain resistance. Some parts of brain cells, such as mitochondria that process chemical energy, work up to 10 hours after death. Thus, in 2007, researchers reported how a woman suffering from acute hypothermia, whose body temperature was below 18 degrees Celsius, had achieved complete neurological recovery.
The "re-life"
Sethan and his colleagues decided to test the complex ability of the mammalian brain to recover. So, they designed what they call the "BrainEx" system.
After recovering the pork heads from the slaughterhouse, four hours later, the organs were connected to a system developed by the team of researchers.
The device rhythmically pumped (to mimic the pulse) a specially created brain around the brain containing synthetic blood containing oxygen and drugs to slow down or reverse the death of brain cells.
The pig's brain received the restoration cocktail for six hours.
The study, published in the journal Nature, showed a reduction in brain cell degradation, a restoration of blood vessels and signs of brain activity.
The researchers also discovered the activity of synapses, the connections between brain cells that allow them to communicate.
The brain also showed a normal response to drugs and used the same amount of oxygen as the normal brain.
Research is transforming the paradigms of brain death. Many thought that this happened quickly and irreversibly without the necessary amounts of oxygen.
Professor Nenad Sestan said, "Cell death in the brain lasts longer than we would have thought."
What we are showing is that the process of cell death is a gradual process and that some of them can be either postponed, retained, or even reversed, he said, quoted by the BBC.
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