The thought of the dead coming back to life evokes images of zombie horror movies like Dawn of the Dead and 28 Days Later. Yet to everyone’s amazement, science fiction could slowly be transforming into science fact. Some have even taken to calling it ‘predictive fiction’ for that very reason. And good predictive fiction often stirs up controversy.
Researchers at the Yale School of Medicine bridged the science fiction gap after they successfully restored some functions to pig brains that had been dead for up to four hours. The study was designed to investigate whether any cellular functions could be restored in a mammalian brain hours after death. The goal of the project is to eventually develop therapies for brain injuries and other neurodegenerative conditions such as Parkinson’s, Alzheimer’s, and Lou Gehrig’s disease (ALS).
Researchers used an artificial perfusion system called BrainEx, which is a device that replicates blood flow. They pumped an experimental solution through the brain bringing oxygen and other vital nutrients to the tissue, which in turn gave brain cells the resources to begin many normal functions. The Yale researchers were astounded with the results. As cells began consuming and metabolizing sugars – the brain’s immune system kicked in, neuron samples could carry signals, and some brain cells even reacted to drugs. (1)
It’s Alive! – Well, Kind Of
Though the brain appeared to be working in a limited capacity, there was no evidence of the kind of neural activity that is thought to signal consciousness, the ability to perceive the environment, or experience sensations such as pain. However, BrainEx did restore and sustain circulation to major arteries, small blood vessels, capillaries, and supported cerebral metabolism. As a control, other brains received either a fake solution or no solution at all. Neither of these groups exhibited revived brain activity and they deteriorated as normal. (2)
Yale researchers have managed to keep some brains alive for up to 36 hours with BranEx and currently, don’t know if the system could have sustained the brains longer. The team stopped the experiment after six hours because of the limited availability of fresh solution and the difficulties of having someone constantly monitor and adjust the BrainEx system. “It is conceivable we are just preventing the inevitable, and the brain won’t be able to recover. We just flew a few hundred meters, but can we really fly?” said Nenad Sestan, Yale neuroscientist and lead researcher. (4)
Lance Becker, an emergency medicine specialist at the Feinstein Institute for Medical Research in Manhasset, New York commented on the study. “This paper throws a hand grenade into the middle of what the common beliefs are, we may have vastly underestimated the ability of the brain to recover.”
An Impending Ethical Quandary
This research signals a massive debate to come regarding medical ethics and our definition of death. In most countries, a person is declared as legally dead if they show irreversible loss of brain or circulatory function. (5) This definition is already at odds with some traditional understandings, but questions remain. How do we classify death if it becomes possible to reverse clinical death with pumps and artificial blood? Another possible consequence involves organ donations. Some countries require emergency responders to use a process that preserves organs when they cannot resuscitate a person. They continue to pump blood through the body but use a “thoracic aortic occlusion balloon” to prevent it from reaching the brain. This process is already controversial because it raises concerns over what actually caused a patient’s death. But what happens when brain death becomes readily reversible?
Stuart Younger, a bioethicist at Case Western Reserve University told Nature that if BrainEx were to become widely available, it could reduce the pool of eligible donors due to the ability to extend the resuscitation window.
“There’s a potential conflict here between the interests of potential donors — who might not even be donors — and people who are waiting for organs.” (4)
The Long Road Ahead
It will likely be a very long time before BrainEx sees it’s first trials with a human brain. In the meantime, scientists and governments are faced with the legal and ethical challenges related to the possibility of creating a conscious brain without a body. Sounds to me like an idea straight from an episode of Futurama.
Christof Koch, president and chief scientist of the Allen Institute for Brain Science in Seattle, Washington commented on the study. “For most of human history, death was very simple. Now, we have to question what is irreversible. This really is a no man’s land.” says Koch.
Koch wants a broader ethical discussion to take place before any researcher tries to induce consciousness in a disembodied brain.
“The law will probably have to evolve to keep up. It is a big, big step” he says. “And once we do it, it’s impossible to reverse it.” (4)
