“Cold is the old thing, and warm is the new thing” when it comes to organ transplants, according to Dr. Korkut Uygun. Uygun is an assistant professor in surgery at Harvard Medical School and founder of Organ Solution, a startup focused on recovering donated livers.

“The current state of the art is the University of Wisconsin (UW) organ preservation solution,” which is a preservation medium for keeping donated organs just above freezing, he says. “It’s a miracle. It enables transplantation as we have it today, [but] now it seems to have reached its boundaries, because we can only use these organs that are already in perfect condition.”

But times are changing.

“Now we are going back to what I like to call ‘functional organ preservation.’ So rather than the static box where the organ is basically suffocating as you transport it to the recipient hospital, we actually hold it in a functional state,” Uygun says. “To some extent it can actually repair itself. The hope and the early indications are that we can actually use some of the organs that are not so perfect to save lives.”

The new technique is called “warm perfusion” and it’s out of this world. In a box with support equipment, lungs are kept breathing and hearts are kept beating. Both of these applications have already been used in clinical trials.

“For all abdominal organs we are talking about switching [to warm perfusion],” Uygun says. “For things like vascular composite tissues (face limbs, hands) there’s a driving force to do the exact same because there’s a lot of muscle, and they still need energy supplied.”

There’s a timeline for integrating this technique with different organs. “For lungs we’ll probably start as soon as possible. It’s already being used; it’s just not the dominant technology,” he says. “It usually takes a few years for these things to say for sure whether they are better or not. The results are already very impressive—and then the same thing will happen for other organs. Heart is probably the next one, and then livers, and then kidneys, and then we’ll talk about other things like hands and limbs.”

Uygun also offers his thoughts on phasing out the current cold technology: “What is great with the old technology is it’s so cost effective and so easy. On the short term, we don’t want to break what’s already working, so we’ll try to push things cautiously. Long term (5-10 years), I think they’re going to try this warm perfusion idea with almost every major organ and every active tissue.”

But cold methods still have their uses. “The old technology is still good for tissues which are not very vascularly linked or metabolically active,” Uygun explains. “If it’s something like cartilage, then you don’t really need to supply it with oxygen and nutrients the whole time, and probably you have enough time to ship it wherever you want.”

How will the field change even further down the road? “In the next 10 years we’ll go back to cold,” Uygun predicts. “In the longer term the idea is to be very efficient in shutting down metabolic activity, so we can actually bank these organs. Cryobiology is the field that popularized this. [So far] we haven’t been very successful with cryo-preserving organs. ”

Uygun predicts warm transfer will be the standard of care in the near future, and that’s nothing short of thrilling. “Transplantation science is such a science fiction field. It’s why I ended up here. It’s extremely exciting. It’s really cutting-edge stuff.”