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t m c » p u l s e | j u n e 2 0 1 9 11 engineering and organ regeneration lab at UTMB. "A lot of things there didn't happen until much later. We really thought outside the box at that time. … It's still kind of science fiction-y now." More than a decade after their first meeting, Cortiella and Nichols took one large step toward turning science fiction into reality by creat- ing and subsequently transplanting four lungs into adult pigs—with no medical complications. Oreo cookies Cortiella and Nichols hope to quell the national shortage of donor organs with bioengineered organs. More than 113,000 patients are listed on the national transplant waiting list, according to the U.S. Department of Health & Human Services. Unfortunately, the organ shortage in the country continues to grow, as the number of patients in need exceeds the number of donors. Another person is added to the waiting list every 10 minutes, while 20 people die each day waiting for a lifesaving organ transplant. Yet a large number of less- than-perfect donated organs are discarded because they don't meet the strict federal criteria for transplantation. In 2016, nearly 5,000 donated organs were thrown out—including 221 lungs—because they were deemed "unsuitable" for transplantation due to "dis- ease, injury to the organ, and the lapse of too much time between recovery and transplantation," according to a 2017 report from the National Academies of Sciences, Engineering, and Medicine. "There are more lungs that are being thrown away than there are being transplanted, so there are a lot more people also waiting on a list to be transplanted. Unfortunately, the majority of them don't get it," Nichols said. "This was a way to look and see if we could take a lung that they're going to throw away or put somewhere, isolate the cells, take the scaffold and then start again." A bioengineered lung hangs in a bioreactor, where it is infused with nanoparticles delivering a special concoction of growth factors. Throughout the entire study, the pigs were trained exclusively with Oreo cookies, which allowed the researchers to perform tests and checkups without the pigs squirm- ing. The team's veterinarian wrote an actual prescription with strict instructions to feed the pigs with Oreos for "pre- and post-transplant enrichment," according to Nichols. In total, the researchers har- vested and transplanted four lungs. As the lungs stewed in the biore- actor for a month, Nichols treated each of the pigs and each lung like a patient awaiting a transplant. "I'd come in in the middle of the night and check on them," Nichols said. "We've got a lung for a pig, and the pig is waiting to receive the lung, so we'd better have a lung to give them. … They were all import- ant to us. They were our transplant patients, and they gave us every- thing to do this research. We couldn't have done it without their involvement." To create the scaffold, the team took a single lung from another pig and stripped the cells—a process called decellularization—using a detergent and sugar solution. The detergent removes all traces of blood and cells, while the sugar protects the collagen and elastin proteins from deteriorating. What is left is an off-white, gauze-like ghost of a lung. Washed clean of all traces of DNA, the lung scaffold is translucent, with only its branching arteries visible. ➟