The experiment, which was reported this year in the journal Nature Medicine, marked a watershed moment: the first time scientists had created a functioning heart in the lab from biological tissue. For the 62 million people living with congestive heart failure, a condition in which the heart is no longer fit enough to pump blood through the body, drugs and heart-repair procedures frequently fall short; 60 percent of patients die within five years of diagnosis. A recellularized heart like Taylor's represents the first real hope for a cure—and she recently brought it one step closer to reality by devising a way to populate it with blood vessels. "There's a lot of smoke and mirrors in this field," says Todd McAllister, the CEO of Cytograft, a California-based tissue-engineering company. "Some people say they can grow a heart from scratch in 10 years, which is ridiculous. But Dr. Taylor's approach is more realistic because it's so simple and elegant. By using an existing heart, she's taken away all of the structural issues."