Only ten to twenty percent of lung-transplant patients survive for ten years, but now scientists hope that statistic will improve. Although normally difficult to grow because of their complex structure and multiple cell types, functional new lungs have been cultivated for the first time in the lab. Laura Niklason of Yale University and colleagues used a technique called decellularization to grow lung organs, and then used the method to produce rodent lungs. By starting with decellularized adult rat lungs and adding a mixture of lung cells from the newborn rats, the researchers were able to grow and nurture new rat lungs in eight days. The next step was to remove the left lung of their lab rats and stitch in the lung replacement. Through x-ray, the team was able to see that the new lungs did inflate, though not fully, and that they were taking oxygen and releasing carbon dioxide. “We’ve shown that it’s possible to engineer a lung that can perform the single most important function – exchange of gases,” Niklason explains. While this breakthrough is a big advance in lung tissue reconstruction, Niklason believes it is likely to be a twenty to twenty-five year project; the next obstacle is to identify cells that can reconstruct lung tissue without provoking the immune system to attack and reject it.