Is cardiac death really irreversible? How to even define death? It was these questions that were raised by the research of a group of scientists from Yale University, who managed to do something unprecedented – they revived some of the organ cells in the body of a pig that had been dead for an hour, so that they began to function again.
The results of the study, which are still preliminary and were published this week in the prestigious Nature magazine, have already managed to shock experts across the field. For example, the magazine quotes Duke University neuroethicist Nita Farahany, who called the experiment stunning. According to her, some limits of the human body, which we thought were insurmountable, may be surmountable.
A “cocktail” of blood and drugs helped
At the heart of the experiment was the attachment of dead pig bodies to a system called OrganEx. The bodies had been dead for an hour by then. The system pumped through them a special solution containing pig blood and 13 different substances, including drugs against blood clots, which slowed down the decomposition of the organism and quickly restored partial function in some organs, such as the heart and liver.
However, no activity was observed in the pigs’ brains, so there is no evidence that this organ regeneration leads to the animals regaining consciousness.
It was the research that was devoted to the brain, but the current study followed up. In 2019, scientists from the same university managed to keep pig brains alive for several hours after removing them from their bodies. When this was achieved, the team was sure that it would also be able to keep organs alive directly in the body, neuroscientist and study author Nenad Sestan explained to Nature.
A similar technique was also used, in 2019 the team connected the brain to the BrainEx system, which they have now only modified and created from it OrganEx. But it was not entirely simple, because originally only the brain, i.e. one specific organ, was counted. The new generation had to handle a wider range of tissues and all the problems associated with them, for example immune.
How the revival went
As for the pigs, they were completely “normal”. The scientists took them from a local farmer, observed them for three days to see if they were healthy, and then put them to sleep. Subsequently, a ventilator was connected and the team induced a cardiac arrest in them. When the pigs no longer had a pulse, they were disconnected from the ventilator.
After an hour, the scientists connected the pigs to the ventilator again and some of the pigs to the OrganEx system. The other part of the pigs was connected to an ECMO machine, providing extracorporeal life support. This is used in severe cases where people’s lungs and heart are failing.
Pigs that were connected to OrganEx actually had oxygen flow throughout their bodies, unlike pigs that were connected to ECMO. The measurements also showed a partial restoration of electrical activity and contractions in the heart, but we cannot speak of a full restoration of function.
Furthermore, the livers of the OrganEx-connected pigs produced much more of a protein called albumin than the other group of pigs, and all key organs showed a greater response to glucose. This means, according to the authors, that the treatment restarted the animals’ metabolism.
Use in transplants and resuscitations
As the results of the study are preliminary, the experiment will first have to be repeated in other animals and only then can it be possible to proceed to potential clinical tests in humans, if the ethics committee allows it at all.
However, according to the authors, the data from these experiments could be as important to medicine as the advent of ventilators or the discovery of CPR, as it could help preserve organs for transplants, which are traditionally in short supply. Currently, the already mentioned ECMO is used for this, but the success rate is not high. Scientists also mention its use in resuscitation.
Source: Web Nature, study