Researchers have partially revived the brains of pigs that had been dead for hours, an accomplishment that suggests new ways of preventing brain damage and possibly holding promise for restoring cell function, according to The Guardian.
In their report, published in the journal Nature, the researchers were careful to clarify that the brains did not exhibit evidence of consciousness, such as different parts of the brain exchanging signals. The development also does not, according to the scientists, alter the definition of death as we know it.
But by pumping oxygen-rich fluid through the brain, researchers believe they could prevent irreversible damage and preserve cell function. The development could open up new avenues to study the inner workings of the brain, and perhaps to new treatments for conditions such as strokes in which blood flow is cut off to the brain, leading cells to die off.
“When we started this study we really never imagined we would get to this point,” according to the study’s lead researcher, Professor Nenad Sestan of Yale University. “This is not a living brain. But it is a cellularly active brain.”
Prior studies have suggested that individual brain cells may be able to survive the loss of blood circulation.
In the new study, researchers connected arteries from pig brains, from animals that had been killed in a slaughterhouse hours earlier, to a system called BrainEx that circulated oxygenated synthetic blood through the brains. In addition to oxygen, the fluid contained nutrients and other substances meant to prevent cell death.
Blood vessels dilated in response to one of the substances, and the brains consumed oxygen and released carbon dioxide at a rate close to that of a normal brain. After being connected to BrainEx for six hours, the brains had not decomposed, unlike brains that hadn’t been connected.
Even more crucially, the cells regained some functions, releasing immune-response substances. Individual neurons continued functioning even after the fluid was removed from the brains.
“What we are showing is that the process of cell death is a gradual, stepwise process and that some of those processes can be either postponed, preserved or even reversed,” according to Sestan.
Researchers said that the fluid included substances that would have blocked brain cell activity, and that there was no “organized global electrical activity” that would suggest consciousness, according to Dr. Stephen Latham, a bioethicist and co-author of the study.