More than 100,000 people are waiting for organ transplants in the U.S. alone; every day 18 of them die. Not only are healthy organs in short supply, but donor and patient also have to be closely matched, or the patient’s immune system may reject the transplant. A new kind of solution is incubating in medical labs: “bioartificial” organs grown from the patient’s own cells. Thirty people have received lab-grown bladders already, and other engineered organs are in the pipeline.
The bladder technique was developed by Anthony Atala of the Wake Forest Institute for Regenerative Medicine in Winston-Salem, North Carolina. Researchers take healthy cells from a patient’s diseased bladder, cause them to multiply profusely in petri dishes, then apply them to a balloon-shaped scaffold made partly of collagen, the protein found in cartilage. Muscle cells go on the outside, urothelial cells (which line the urinary tract) on the inside. “It’s like baking a layer cake,” says Atala. “You’re layering the cells one layer at a time, spreading these toppings.” The bladder-to-be is then incubated at body temperature until the cells form functioning tissue. The whole process takes six to eight weeks.