The Pigs Died. Then Scientists Revived Their Cells

The pigs had he’s been dead for an hour. Cause: cardiac arrest. But six hours after Yale University researchers connected their bodies to a machine that pumped a nutrient-rich fluid, their organs began to show signs of life again.

Although the organs did not suddenly start functioning normally, some of the cellular damage caused by the loss of blood flow after death appeared to be reversed. The pigs’ hearts emitted electrical activity. The cells in his kidneys, liver and lungs were working again and showing signs of repair. The discovery, published Wednesday in the journal Nature, suggests that cell death could be delayed longer than is currently possible. If these processes could be slowed, it could mean saving more organs for transplant.

“This new system showed that not only can we slow down cellular damage, but we can actually activate processes at the genetic level for cellular repair,” says Brendan Parent, assistant professor of bioethics at New York University , who did not participate in the study, but wrote a commentary in Nature at his side. “This could force us to reconsider what we decide is ‘dead’.”

In 2019, the Yale team challenged the idea that brain death is definitive when they reported that they had partially revived the brains of pigs for hours after the animals had been sacrificed. For the current experiment, the researchers wanted to see if the same method, in which a blood substitute is brought into the animal’s circulatory system, could also be used to revive other organs.

“We have restored some functions to cells across multiple vital organs that would have been dead without our interventions,” lead author Nenad Sestan, a Yale neuroscientist, told reporters on a call Tuesday. “These cells are working hours after they shouldn’t be working, and what this tells us is that the death of the cells can be stopped and their functionality can be restored in multiple vital organs, even within an hour. after death.”

Deepali Kumar, president of the American Transplant Society and a professor of medicine at the University of Toronto, says that with further refinement, the system could one day be used to expand the pool of human organs available for donation. “There is a significant shortage of organs for transplantation, and we certainly need new technologies that can help improve the supply of organs,” he says.

In the United States, about 106,000 people are on the national transplant waiting list, and 17 people die each day waiting for an organ, according to the federal Health Resources and Services Administration. Despite the enormous need, around 20 percent of organs are discarded each year due to poor quality. This could mean they are too old or damaged, which can happen when organs are cut off from an oxygen-rich blood supply for too long.

The standard practice for preserving organs for transplantation is static cold storage. Cooling organs quickly after removal reduces their oxygen demand and can prevent cell death, but does not save all organs. There is also growing interest in using a technique called extracorporeal membrane oxygenation, or ECMO, for patients who cannot be resuscitated, in order to preserve their organs for transplant. Typically used as life support for patients whose hearts or lungs are severely damaged, an ECMO machine pumps blood out of the body to remove its carbon dioxide and add oxygen, then returns it to the body.

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