Scientists have demonstrated a new system that can restore crucial molecular and cellular functions in pigs one hour after death. Experiments showed that some tissue damage from loss of oxygen can be reversed, which could widen the organ transplantation pool and may even lead to new treatments for heart attacks.
After the heart stops beating, the supply of oxygen and other nutrients to organs is interrupted, and within minutes cellular death and tissue damage begins that’s usually thought to be largely irreversible. As such, organs often degrade too quickly for transplantation, leading to worldwide shortages. There are methods for preserving individual organs, but the ultimate goal would be to restore circulation to the whole body and save all the organs at once.
Now, researchers has made a breakthrough in doing just that. They started with a system called BrainEx, which they demonstrated in 2019 by restoring some brain function to pigs as long as four hours after death.
The new system, named OrganEx, is essentially a scaled-up version of that technology. The machine is connected to an animal's natural circulatory system, pumping through a fluid specifically designed to counteract the metabolic and electrolyte imbalances that occur after blood flow stops.
The team tested the system in pigs, and compared it to an existing circulation-restoring technology known as an extracorporeal membrane oxygenation system (ECMO). These were hooked up to pigs one hour after cardiac arrest, followed by six hours of circulation with the restoring fluid.
The group that received the OrganEx treatment showed much higher tissue integrity, and reduced cell death, hemorrhaging and tissue swelling than those treated with ECMO. Even better, some key molecular and cellular processes were restored in several organs of the OrganEx pigs, including the heart, brain, liver and kidneys. Gene expression patterns indicated that even some repair processes were occurring in the body.
"Under the microscope, it was difficult to tell the difference between a healthy organ and one which had been treated with OrganEx technology after death,” said Zvonimir Vrselja, an author of the study.
The team notes that no electrical brain activity associated with normal brain function was detected during the procedure, so any “zombie pig” concerns can be put to rest.
Instead, the team says that the breakthrough highlights that mammal bodies can recover far better from interruptions to blood flow than was previously realized. While there’s still much more work to be done to investigate the technique, OrganEx could help save more organs for transplant, or lead to new treatments for recovering from heart attacks or stroke.
The research was published in the journal Nature.