It is hard to mend a broken heart, but in a few years doctors might be able to do essentially that. Scientists are closing in on ways to help patients grow new heart muscle after a heart attack, as well as new lung tissue to treat fibrosis, corneas to erase eye pain, and other body parts to gain a new chance at life.

If the science works, it could represent a new approach to medicine: reversing rather than alleviating chronic illnesses. The idea “is really to restore function to the organ such that the quality of life of that person is normalized,” said one expert.

The need for regenerated hearts alone is huge. Up to 3% of the world’s population suffers from heart failure, in which a heart whose muscle has been damaged by a heart attack or another disease gradually loses its ability to pump blood. The condition affects about 6.5 million people in the U.S. and is the leading cause of hospitalization among Medicare patients.