Source: Zvonimir Vrselja, Stefano G. Daniele, John Silbereis, Francesca Talpo, Yury M. Morozov, André M. M. Sousa, Brian S. Tanaka, Mario Skarica, Mihovil Pletikos, Navjot Kaur, Zhen W. Zhuang, Zhao Liu, Rafeed Alkawadri, Albert J. Sinusas, Stephen R. Latham, Stephen G. Waxman & Nenad Sestan. Restoration of brain circulation and cellular functions hours post-mortem. Nature 568, pages336–343. 2019. DOI: 10.1038/s41586-019-1099-1
Historically, those who attempted to reverse works of the Grim Reaper were ridiculed and labeled as “mad scientists” like the fictitious Dr. Victor Frankenstein. In modern times, the lofty pursuit of resurrecting organic matter is not viewed as deranged, but rather ingenious.
Scientists at the Yale School of Medicine recently dipped their toes into the macabre to bring a pig back to life… well, bring its brain back to life… sorta. In a study lead by Neuroscientist Nenad Sestan, researchers succeeded in restoring rudimentary cellular activity in a pig brain four hours after death.
Whether it be human or pig, all mammalian brains share a similar design and function. The brain is comprised of billions of cells called neurons. These specialized cells have a unique electric language. By transmitting an electrical signal to a neighboring neuron, the cell relays a message to the nerves which radiate throughout the body.
Prior to this study, neuroscientists believed large mammalian brains were irreversibly damaged within minutes of being cut off from oxygenated blood flow. It has been accepted fact that the brain was an extremely fragile organ.
Through their studies Sestan and collaborators repeatedly witnessed cellular viability in small samples of mammalian brain tissue harvested hours after death. With this knowledge, Sestan and his team theorized mammalian brains could have the same viability.
To test their theory, the researchers experimented on more than 300 pig brains over six years. In order to prevent decay, the researchers had to create a system to circulate oxygen and nutrients to the intact brain. After six years of trial and error, they succeeded in doing so by creating BrainEx, a machine that acts as a substitute heart pumping fluids throughout the brain.
With BrainEx up and running, Sestan’s team conducted a comprehensive study on 32 intact pig brains. The specimens were hooked up to BrainEx four hours postmortem. The brains were injected with a preserving liquid that acted as a synthetic blood, which circulated through the organs for 6 hours.
While BrainEx pumped oxygenated fluids throughout the organ, Sestan and his team noted something remarkable: Many of the neurons ceased decomposition. Even more miraculous, some neurons were revived. The revived neurons resumed rudimentary cellular activity such as consuming oxygen and glucose. These neurons also responded to electrical and pharmaceutical stimulation.
Despite successful neuron revival, the brain never regained consciousness. The organ lacked signs of coordinated electrical signals meaning the subject lacked higher brain functions such as cognitive functions or the ability to feel. It was a cellularly active brain, not a living brain.
So, the team did not bring back a brain from beyond the grave, but that was never their intention. Sestan did not want to restore full brain function in the specimen do to the complicated ethics of resurrection. As a matter of fact, his team took careful precautions to prevent bringing Babe back from the dead.
The importance of Sestan’s discovery is two-fold. First, it will allow scientists to study intact brains hours after death. Previously, scientists were restricted by only being able to study small pieces of brain tissue. This is like trying to figure out a massive puzzle with just a handful of pieces. Second, the regeneration of neurons holds promise for future research into reversing or preventing further damage after severe brain injuries.