For the first time, a group of researchers have created lungs in a laboratory and successfully transplanted them to a pig.
These bioengineering lungs, described Science Translational Medicine, developed healthy blood vessels that allowed pigs live for several weeks after surgery without medical complications.
Unlike other cases of transplanted lungs in mice that only lasted a few hours, they seem more viable. If the new procedure can be adapted to humans, with bioengineered lungs grown from a patient's own cells, the risk of organ rejection could be reduced and the waiting times for organ transplants could be shortened.
For the study, the immunologist Joan Nichols and his colleagues from the medical branch of the University of Texas at Galveston built lungs for four pigs using first a mixture of sugar and detergent to remove lung cells from donor pigs. Each designed lung grew for 30 days inside a bioreactor tank, full of nutrient cocktails that helped the cells stick to the scaffold and multiplied in the right places. Finally, the researchers replaced the left lung of each pig with the bioengineering version.
After surgery, Nichols' team got a pig to survive for ten hours, another for two weeks, a third for a month and the fourth for two months. None of the animals received immunosuppressive drugs, and none of the transplants was rejected. Within the body of a pig, the bioengineering lung blood vessels were connected to the animal's natural circulatory system, supplying the organ with oxygen and nutrients to survive.
However, while the bioengineering lungs joined with the pig circulatory systems, the organs were not connected to the animals' pulmonary arteries, which carry low oxygen blood so that the lungs replenish the oxygen from the inhaled air. That forced the pigs to rely on their natural right lung after surgery. The next step is to connect the organ to the pulmonary artery "to ensure that genetically engineered lungs can also carry out this task..