Scientists blur border between life and death by revving organs in dead pigs

Scientists reanimate dead cells in pigs, a potential breakthrough for organ transplants

The new research challenges the idea that the beginning of cell death is irreversible, though bioethicists say it also poses significant questions.

New research is confounding conventional wisdom about life and death.

Researchers at Yale University used a new technology to restore cells in some organs of pigs that had just died, bringing the animals’ cells back to function. The findings, which were published Wednesday in the scientific journal Nature, raise profound ethical questions about how medicine defines death but also teases new possibilities for the collection of human organs for transplant.

“My eyes went wide,” Brendan Parent, an assistant professor of bioethics at the NYU Grossman School of Medicine, said about the moment he first read the new findings. “My brain went to all the crazy places we could go in 20 or 30 years.” Parent was not involved in the study, but was asked by Nature to write a commentary discussing the implications of the new technology.

The research is still in an early, experimental phase and many years from potential use in humans. It could ultimately help to extend the lives of people whose hearts have stopped beating or who have suffered a stroke. The technology also shows potential to dramatically shift how organs are collected for transplant and increase their availability to patients in need.

When the heart stops beating, blood flow is cut off from the body in a process called ischemia and a cascade of biochemical effects begins. Oxygen and nutrients are cut off from tissues. Cells begin to die. It’s a path toward death that causes damage that scientists have considered irreversible.

The new research challenges that idea.

“The demise of cells can be halted,” Dr. Nenad Sestan, a professor of neuroscience at the  Yale School of Medicine and an author of the new research, said during a news conference. “We restored some functions of cells across multiple organs that should have been dead.”

The Yale researchers accomplished this feat by constructing a system of pumps, sensors and tubing that connects to pig arteries. They also developed a formula with 13 medical drugs that can be mixed with blood and then pumped into the animals’ cardiovascular systems. The research builds on previous work at Yale, which demonstrated that some damage to brain cells could be reversible after blood flow was cut off. Yale has filed a patent for the new technology, but is making its methods and protocols freely available for academic or nonprofit use, the study says.

To evaluate how well the new system, called OrganEx, works, the researchers caused heart attacks in pigs that had been anesthetized. The pigs were dead for an hour, and the researchers cooled their bodies and used neural inhibitors to ensure the animals did not regain consciousness during subsequent experiments.

Then, the researchers began to use the OrganEx system. They compared its performance against ECMO, a life-support technology used in hospitals today in which a machine oxygenates blood and circulates it throughout the body.

OrganEx restored circulation and prompted the repair of damaged cells. For example, the scientists saw heart cells contract and electrical activity return. Other organs, including kidneys, also showed improvements, the study says.

The pigs treated with OrganEx startled researchers. During experimentation, the dead pigs’ heads and necks moved under their own power. The animals remained under heavy anesthesia.

“We can say that animals were not conscious during these moments and we don’t have enough information to speculate why they moved,” Sestan said.

The researchers do view the neck jerk is an indication some muscle function was restored after death.

The OrganEx research is a single study in a laboratory setting in which researchers had total control over the circumstances of the pigs’ death and treatment. Even so, the early results open up possibilities that would have seemed like science fiction a few years ago.

“The assumption that loss of oxygen to the brain or organs within seconds to minutes means those organs are irretrievably damaged and loss — that’s not true,” said Nita Farahany, a neuroethicist and law professor at Duke University, who was not involved in the study.

The definition of death is a moving target that has shifted as new life-support technology like ventilators or ECMO were developed. Ethicists view OrganEx as ECMO on steroids and something that could change the definition of what medical death means.


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