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Connecting human lungs to live pigs could help with transplants, study finds

Swine may breathe new life into transplant waitlists, scientists have found.

Over 360 people in the US died while waiting for a lung transplant in 2018, but new findings show that such individuals’ fates may no longer be determined by shortages of quality organs: Live pigs could restore lungs previously unfit for transplant.

In research published this month in the journal Nature Medicine, study authors reported that they were able to heal damaged human lungs by connecting them to a live pig’s circulatory system. Researchers acquired six donor lungs — all deemed too damaged to be transplantable — and connected them to a pig’s neck, allowing the pig’s blood to flow through the lungs and back into the pig.

The damaged lungs all showed signs of recovery after 24 hours of cross-circulating the pig’s blood.

“We were able to repair these lungs and achieve remarkable improvements in their function,” Gordana Vunjak-Novakovic, senior study author and Columbia University biomedical engineering professor, told OneZero of the findings.

“The idea was if we could at least temporarily support these human organs, they would recover from these acute reversible injuries, and then we would be able to utilize them for transplantation,” added Matthew Bacchetta, co-author and Vanderbilt University associate professor. “If we could increase our recovery rate on organs, it would open up the opportunity for more transplants for people who need them.”

Indeed, only about 20% of donated organs are in good enough condition to be transplanted, and even premium lungs only have a six- to eight-hour window after being harvested before they too become unsuitable, OneZero reported. While researchers can now use the ex vivo lung perfusion, or “lung in a box” technique, to sustain donated lungs a bit longer, and new curative medicines make lungs with hepatitis C transplant-viable, the pig cross-circulation tactic could be an even bigger discovery.

The findings come at a vital moment: Over 1,000 people are waiting for lung transplants in the US, a number which may soon skyrocket because of the coronavirus pandemic.

“We don’t know how many of the 3 to 4 million Americans who have been infected with COVID-19 will need an organ transplantation a few years from now,” Abbas Ardehali, UCLA Heart and Lung Transplant Program surgical director — who was not involved in the study — told OneZero. “There could potentially be a tsunami of need for lung transplantation in the years to come.”

More research is still necessary to confirm there aren’t any adverse side effects from the method before it can be tested on lung transplant patients, a necessary step before it is implemented for routine use.

pig-lungs
Illustration of the envisioned application of cross-circulation to expand the number of organs that can be used for life-saving transplants.Ahmed Hozain and John O'Neill/Co