Scientists Partially Revive Disembodied Pig Brains, Raising Huge Questions – gizmodo.com– by George Dvorsky – Apr 2019
Researchers from Yale have developed a system capable of restoring some functionality to the brains of decapitated pigs for at least 10 hours after death.
Developed by neuroscientist Nenad Sestan and his colleagues from Yale University, the system was shown to restore circulation and some cellular functionality to intact pig brains removed from the skull.
The brains were hooked up to the system, known as BrainEx, four hours after death was declared and after severe oxygen starvation, or anoxia, had set in.
The system pumped synthetic blood and other compounds into the disembodied organ, restoring partial functionality for a period of six hours. This research was published today in Nature.
If they have developed a functional “blood substitute”, it would be far more valuable to humans in need of transfusions when these are in short supply during mass emergencies, like huge natural disasters and wars.
It seems silly to go to all this effort and expense and then use it only for such an experiment when there is a very real need “on the ground”.
Importantly, the brains did not exhibit signs of consciousness or awareness, and the researchers took extra precautions to ensure that didn’t happen
The ability to restore partial functionality to a mammalian brain after death could result in a new model for studying brains and new medical interventions for diseases or conditions in which the brain is starved of oxygen, including strokes.
At the same time, however, the new achievement is straining our notion of death and when it should be declared—a development with implications ranging from animal experimentation through to human organ donation
studying clumps of cells in a petri dish is a far cry from being able to study a whole brain.
But sometimes my brain feels like just “a clump of cells in a Petri dish”, ruled by noxious chemical sequences completely out of my control.
scientists have struggled to understand the various processes that happen in the brain after death, such as the capacity of the brain to retain certain functions like circulation, and the rate of cellular death.
The purpose of the BrainEx experiment was to “better understand how brain cells react to circulatory arrest” and “test whether some cellular functions can be restored in the brain after death,”
Mammalian brains need lots of oxygen. Interrupted periods of oxygen-enriching blood flow, even for short periods, cause neurons to die, resulting in serious brain damage.
Anoxia, as this physiological process is called, also sets in after death. The new study was designed to assess the severity of this damage post-mortem, and whether certain brain functionality can be partially restored in the immediate hours after death is declared.
To test this possibility, Sestan and his team developed a system that provides blood flow to the brain at normal body temperature.
The custom-designed device mimicked natural organ systems inside the body, pumping a protective solution designed to promote recovery from prolonged anoxia. This artificial blood supply was delivered to isolated pig brains, preventing some of the decay typically associated with death.
The brains were removed from the skulls and hooked up to the BrainEx device four hours after death (so these brains experienced four hours of anoxia).
The brains remained on the system for six hours as the researchers carefully monitored for activity. Remarkably, the six hours of synthetic blood perfusions resulted in a restoration of cellular functionality, along with the prevention of swelling and other factors responsible for cellular damage and death. It even sparked some synaptic activity.
In addition to reducing cellular death, BrainEx preserved circulatory function in major arteries and small blood vessels.
Importantly, no higher level functionality was detected to indicate the presence of consciousness, awareness, or perception. An EEG device did not detect the signals associated with consciousness, namely low-amplitude waves in the alpha range (8-12 Hz) and beta range (13-30 Hz). No evidence emerged to suggest wide scale, full function in the pigs’ brains
To be safe, however, the researchers used neuronal activity blockers to prevent conscious awareness from arising during the experiment.
I’m surprised by the great effort made to ensure these brains “on a slab” wouldn’t suffer even the slightest suffering from either physical or mental pain, while we pain patients are expected to tolerate pain for the rest of our lives, even when an effective intervention (opioids) is available.
the scientists were confident the BrainEx system isn’t capable of reviving consciousness.
“I want to make it clear that consciousness was never detected in the course of research,” said Sestan. “It was never a goal of the research to induce consciousness in the brains.”
That said, his team “was prepared to induce anesthesia, lower the temperature of the brains,” and do whatever was required to “cease any activity should it occur,” he said. This is “not a living brain, but a cellularly active brain,” he added
This experiment shows that, under the right conditions, a large, disembodied, intact mammalian “brain possesses an underappreciated capacity for restoration of microcirculation and molecular and cellular activity after a prolonged post-mortem interval,” concluded the researchers in the study.
The degree to which this system could be used to preserve the brain even further is not clear.
Bioethicist Kerry Bowman from the University of Toront: “The definition of death in many western nations turns on the concept of an irreversible loss of all brain function. This study challenges that very concept,” Bowman wrote
“Although there was no EEG activity detected, or evidence of consciousness, this could possibly be reflective of the study design.
This study adds to a growing awareness that death is not a precipitous event but a gradual process. Over time this could potentially lead to challenges to the legal concept of brain death as a valid definition of death.”
Existing animal research ethics protocols may be increasingly inadequate, said Bowman, as nonhuman animals could potentially be kept in an undefined realm between life and death
So “zombies”, creatures that are alive, but without consciousness, are now a technical possibility. As they say, truth is stranger than fiction.
the new research upends two major assumptions about death and its immediate effects on the brain:
- First, that neural activity and consciousness are irretrievably lost within seconds to minutes of interrupting blood flow in mammalian brains.
- Second, that, unless circulation is quickly restored, there is a largely irreversible progression towards cell death and the death of the organism..
Even with all the unknowns, the discovery that mammalian brains can be made to seem ‘slightly alive’, hours after the animals had been killed, has implications that ethicists, regulators and society more broadly must now think through
..In our view, new guidelines are needed for studies involving the preservation or restoration of whole brains, because animals used for such research could end up in a grey area—not alive, but not completely dead.
Why are they so concerned about “dead” test animals’ suffering, when the world is full of human suffering for so many?
…bioethicists Stuart Youngner and Insoo Hyun said the new study is challenging the long-held assumption that big brains are hopelessly damaged in the few minutes following death.
“It also raises the possibility that researchers could get better at salvaging a person’s brain even after the heart and lungs have stopped working,” wrote Youngner and Hyun.
It scares me that they might not let us die and instead, keep us alive for their own purposes long after our enjoyment of life (or even consciousness) has ended.
I can foresee a situation where hospitals are rated on how many people die in them and, thus motivated, they’ll keep patients alive to keep their good ratings, a problem already found for complicated surgeries.
the BrainEx scientists were quick to downplay the broader philosophical implications of their research, saying the system isn’t remotely close to being capable of fully restoring brain function.
If “real” death becomes controllable, then doctors would need “permission” to let someone die. Who would have the freedom or authority to grant this permission?
That may very well be the case, but this research is laying the groundwork for more substantive breakthroughs in this area. It’s therefore critical that we discuss these important issues now as we get increasingly better at keeping brains alive.
And, just so you know this isn’t some fringe experiment by mad scientists, even the New York Times had an article on it:
The ethical issues posed by research into revived brain tissue are nearly unprecedented. Among them are questions about the welfare of laboratory animals.
How, he asked, will ethicists decide if suffering caused by the research — to a “partly alive” brain — is justified by the goals?
Even though there was no electrical activity in the brains, it may be possible to restore it, Dr. Farahany and other experts said. It’s not known what would have happened if the scientists’ solution had not contained nerve blockers.
When you have a cellularly active brain, what are the appropriate protections, she asked.
Do you treat it like a living animal?
You can’t treat it like a dead animal, she said.
Why not? That’s exactly what it is 4 hours after slaughter and decapitation.
We seem to be edging closer to the science fiction idea of the Futurama TV series: maintaining humans forever as a “brain/head in a jar” of nutrient soup.
The work also may have implications for organ donation.