The pig study raises questions about the line between life and death: US scientists used a special perfusion system – called OrganEx – to restore some cell and organ functions to pigs that had been dead for an hour. This is reported by a team from Yale University in the journal “Nature”.
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“Even under a microscope, it was difficult to tell a healthy organ from one that was treated with OrganEx after death,” co-author Zvonimir Vrselja said in a statement from the university. “These recent results raise many questions, not the least of which is whether the medical and biological determination of death needs to be revised,” writes Brendan Parent of New York University in a commentary on Nature.
What is it about? If mammalian cells are cut off from oxygen, a cascade of various disintegration processes begins, at the end of which cells, organs, and sometimes even the entire body die. However, it is doubtful how long it will take for irreversible damage to occur.
The Yale team, led by neurologist Nenad Sestan, raised this question three years ago. During this time, the team restored some cell activity in the pigs’ brains that had been slaughtered about four hours earlier.
At that time, using a specially designed machine, they pumped a special solution through the main arteries of the heads, and six hours later, they discovered that some cell functions were still intact – such as nerve cell activity, metabolic activity, or blood vessel reactions to drugs, for example.
This is where current research comes in, which goes far beyond its time: “If we were able to restore certain cell functions in the dead brain – the organ known to be the most sensitive to ischemia – we assumed that something similar would also be possible in others. vital organs would be possible, ”explains Sestan.
It stimulates the body’s repair processes
The team tested it in pigs after cardiac arrest. An hour after his death, the scientists linked the animal circulation to the OrganEx machine. This pumped the mixture of animal blood and a special fluid into the circulatory system for six hours according to a special scheme.
This perfusate contained several special ingredients, including anticoagulants, anti-inflammatory, anti-immune and anti-cell death agents. “We were able to restore circulation throughout the body, which surprised us,” concludes Sestan.
The team then recorded the restored function of cells and sometimes even organs in many organs such as the heart, liver and kidneys – for example, the heart’s ability to contract. Gene expression analyzes have shown that repair processes take place in the body.
The technology is not yet ready for human use
Scientists even recorded complex movements of the torso, neck and head in many joints and muscle units. This shows that some motor functions are preserved. As in 2019, the team also found cell activity in the brain, but no evidence of electrical activity or even consciousness.
“Overall, our technology needs to be further optimized and expanded to fully understand its wider implications for hypoperfused tissues,” the team writes.
The researchers point out that this applies particularly to the regeneration of certain functions of the brain, as well as to previously unexplained movements of the neck and head. The technology is very promising, but still far from being used in humans, the researchers said at a press conference on Tuesday afternoon.
The future “The potential of new treatment strategies”
“This comprehensive and well-planned study has the potential to open up new treatment strategies for people who have had a heart attack or stroke,” says Robert Porte of Groningen University Hospital in a commentary to Nature.
“It is conceivable that the OrganEx system (or its components) could be used to treat such people in an emergency.” However, before doing this, the safety of the procedure should be clarified. However, the system is most important for organ donation.
Jan Gummert from the Heart and Diabetes Center NRW in Bad Oeynhausen tells about a very exciting study. “If these data were confirmed, then the use in transplant medicine would certainly be conceivable” – says the director of the Department of Thoracic and Cardiovascular Surgery.
Transplant surgeon Uta Dahmen from Jena University Hospital is also impressed. “This system and the knowledge gained through it have great potential for a wide range of clinical applications,” says the Head of Experimental Transplant Surgery. You can imagine, for example, the improvement of organs previously damaged prior to transplantation, or the treatment of organs that do not have sufficient blood supply after a heart attack.