Restoration of circulation in the brain a few hours after death
Previously it was believed that after a cardiac arrest or cessation of brain activity for other reasons, without oxygen and electrical activity, brain cells begin to die after a few minutes, and this process is irreversible. In this regard, the doctors declared that the patient was brain dead, which was the legal basis for acknowledging death.
A study by scientists at Yale University in New Haven - Zvonimir Vrselja, Stefano G. Daniele et al. - showed that this is not the case.
Experts have previously challenged the previous approach, because:
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However, to date, alternative hypotheses have not been subjected to experimental verification.
In a study published in Nature on April 17, 32 pig brains were involved, each of which was already dead for 4 hours at the time of the survey.
Scientists have developed a Brainex device that supplied the blood substrate to the vessels of the brain extracted from the body: nutrients, substances for contrast on ultrasound - and another to prevent neuron electrical activity (in order to protect cells from damage, as well as for ethical reasons - to do not interfere with the possible effects of brain activity outside the body, even hypothetically).
These brains maintained metabolic activity (sugar absorption, carbon dioxide release) and immune responses, cytoarchitecture, cell death was weakened in them compared to the control group, where no recovery actions were taken. They also maintained electrical conductivity during stimulation from the outside.
Coordinated electrical activity, which, according to scientists, could talk about the flow of conscious processes, was not observed.
Thus, the brain is able to survive much longer than previously thought. And this allows us to look at the question of resuscitation and the onset of death from a new angle.
“For most of human history, death was very simple,” says Christoph Koch, President and Chief Researcher of the Institute of Brain. Allen in Seattle, WA. “Now we have to call into question THAT is irreversible.”
Original source
Ethical discussion
A study by scientists at Yale University in New Haven - Zvonimir Vrselja, Stefano G. Daniele et al. - showed that this is not the case.
Experts have previously challenged the previous approach, because:
')
- Studies on cats and monkeys have shown that brain activity can be fully restored even a few hours after the complete cessation of oxygen: science.sciencemag.org/content/168/3929/375 , www.sciencedirect.com/science/article/pii/0006899374904788 ;
- The experience of people who have experienced stroke and acute hypothermia has shown that when blood circulation is restored, the brain returns to functioning in a life-adaptive format: emj.bmj.com/content/24/7/511.short , www.nejm.org/doi /full/10.1056/NEJMoa1713973;
- Cells extracted from the brain and placed in a “cup” survived in the laboratory for several weeks: www.fasebj.org/doi/10.1096/fj.01-0504com .
However, to date, alternative hypotheses have not been subjected to experimental verification.
In a study published in Nature on April 17, 32 pig brains were involved, each of which was already dead for 4 hours at the time of the survey.
Scientists have developed a Brainex device that supplied the blood substrate to the vessels of the brain extracted from the body: nutrients, substances for contrast on ultrasound - and another to prevent neuron electrical activity (in order to protect cells from damage, as well as for ethical reasons - to do not interfere with the possible effects of brain activity outside the body, even hypothetically).
These brains maintained metabolic activity (sugar absorption, carbon dioxide release) and immune responses, cytoarchitecture, cell death was weakened in them compared to the control group, where no recovery actions were taken. They also maintained electrical conductivity during stimulation from the outside.
Coordinated electrical activity, which, according to scientists, could talk about the flow of conscious processes, was not observed.
Thus, the brain is able to survive much longer than previously thought. And this allows us to look at the question of resuscitation and the onset of death from a new angle.
“For most of human history, death was very simple,” says Christoph Koch, President and Chief Researcher of the Institute of Brain. Allen in Seattle, WA. “Now we have to call into question THAT is irreversible.”
Original source
Ethical discussion
Source: https://habr.com/ru/post/450062/
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