Groundbreaking experiment brings dead pig brains partly back to life

19 Apr 2019

Image: © Angel Simon/

Researchers have restored basic brain functions in a dead pig, raising serious ethical questions when it comes to brain damage.

Is the brain really ‘dead’ when starved of oxygen for a prolonged period of time? That was the focus of a study of which the results have been published in Nature, revealing a groundbreaking discovery that could upend our thinking on life and death itself.

As part of the experiment, the researchers created an artificial circulation system and connected it with the brains of pigs that had died just four hours prior. In doing so, the neuroscientists discovered that this successfully restored some key functions and structures within the donated brains.

While there was no evidence of restored consciousness in the pigs, the result challenges the notion that mammalian brains are fully and irreversibly damaged by a lack of oxygen.

“The assumptions have always been that after a couple minutes of anoxia, or no oxygen, the brain is ‘dead’,” said Stuart Youngner who co-authored a commentary piece about the study with Insoo Hyun, both of Case Western Reserve University in the US. “The system used by the researchers begs the question: How long should we try to save people?”

In the experiment, the researchers used a type of cell-free ‘artificial blood’ – known as artificial perfusate – that helped brain cells maintain their structure and some functions. Resuscitative efforts in humans, such as CPR, are also designed to get oxygen to the brain and stave off brain damage.

If such efforts fail, the medical responders will declare the patient dead, but the amount of time given to such resuscitative efforts varies quite a lot depending on the country, hospital or even emergency team. In Europe, for example, responders who have declared a patient dead will restart resuscitation to keep blood circulating in organs that would later be taken for transplantation.

Ethical questions

However, this latest pig experiment shows that it might be possible to keep the brain alive in humans if the right technology is developed. While admitting that this possibility is a long way off yet, Youngner said that it means people declared legally dead after a catastrophic loss of oxygen could become candidates for brain resuscitation, instead of organ donation.

“As we get better at resuscitating the brain, we need to decide when are we going to save a patient, and when are we going to declare them dead – and save five or more who might benefit from an organ,” Youngner said.

In the meantime, given that brain resuscitation strategies are in their infancy, this study will likely trigger a series of scientific and ethical discussions and, according to Hyun, he and Youngner wrote their commentary in a bid to “get ahead of the hype and offer an early, reasoned response to this scientific advance”.

“We urge policymakers to think proactively about what this line of research might mean for ongoing debates around organ donation and end of life care,” Hyun said.

Colm Gorey was a senior journalist with Silicon Republic