Of the more than 4,000 people in the U.S. waiting for a heart transplant, only about 2,500 will get one this year. Even among those lucky few, however, many of the patients' bodies will attack the foreign cells within them and reject the transplant. It's clear that we need a better way, and medical researchers have been hard at work trying to find one. The dream is to figure out a way to grow whole, beating human hearts from a patient's own cells, and in 2016, scientists from Massachusetts General Hospital and Harvard Medical School got the closest we've ever come to that goal.
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