Scientists from Yale University restored circulation and cellular activity in a pig's brain four hours after its death.
The study published on Wednesday in the journal Nature showed that some basic cellular functions were observed in the brain of a postmortem pig obtained from a meatpacking plant and circulated with a chemical solution.
The researchers said that the brain showed no recognizable global electrical signals associated with normal brain function like perception, awareness, or consciousness, so "this is not a living brain, but it is a cellularly active brain," according to the paper's co-first author Zvonimir Vrselja, a neuroscientist at Yale.
Cellular death within the brain is usually considered to be an irreversible process. Cut off from oxygen and a blood supply, the brain's electrical activity and signs of awareness disappear within seconds, while energy stores are depleted within minutes.
But Yale researchers found the small tissue samples could show signs of cellular viability four hours after death as they connected the vasculature of the brain to circulate a uniquely formulated solution they used to preserve brain tissue.
They found that certain neuronal, glial, and vascular cell functionality was restored.
It is unclear whether this approach can be applied to a recently deceased human brain, since the solution used lacks many of the components found in human blood like the immune system and other blood cells.
The findings have no immediate clinical application, but they may one day lead to ways to help salvage brain function in stroke patients, or test the efficacy of novel therapies targeting cellular recovery after injury, according to the study.