Transplanting any organ is, unsurprisingly, a complicated process, but lungs are particularly vulnerable to damage before being implanted. Now, researchers at Columbia Engineering and Vanderbilt University have developed a way to repair that damage, keeping the lungs of pigs alive outside the body for up to 36 hours and allowing them to bring the organ up to a transplantable quality.

According to the researchers on the study, up to 80 percent of donated lungs are considered too damaged for transplantation. The most common injury is caused when gastric material makes its way into the respiratory tract, where it can start dissolving important tissue.

Rather than just let these crucial and scarce organs go to waste, the team set out to develop a new way to rehabilitate damaged lungs to the point that they can then be transplanted. In experiments with pigs, the team removed a lung from one animal, damaged it with gastric material, and then set about repairing it.

Few machines can stack up against the body itself, so the researchers tapped into that with a cross-circulation system. They hooked up the donated lungs up to the recipient animal, so that its blood would flow through the damaged tissue and back into the body. Using this technique, the researchers managed to keep the lungs alive and breathing outside the body for 36 hours.

In that time, the cells in the organs regenerated themselves, resulting in improved lung function. By the end, the regenerated lungs met all the quality criteria currently required for transplantation.

It also gave the doctors more time to evaluate the organs and explore new ways to fix the damage. Normally that window is only about six hours, so giving them more time to examine the options could reduce the rates of donated lungs that go to waste.

"Our work has established a new benchmark in organ recovery," says Matthew Bacchetta, senior author of the study. "It has opened up new pathways for translational applications and basic science exploration. We have literally spent years refining this technology to improve the recovery and regeneration of organs."

The next steps are to look deeper into how well the repaired lungs function, how safe the method is, and how they respond to drugs given to patients after transplantation. If all goes well, other organs might benefit from similar techniques.

It's been a big few months for keeping pig organs alive outside of the body. In April, researchers reported they had partially restored function to pig brains some four hours after death, which could help repair damage caused by strokes or heart attacks – and may even challenge our understanding of death itself.

The new research was published in the journal Nature Communications. The team demonstrates the technique in the video below.

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