The answer may now have been discovered in at the University of Minnesota, where, using 3-D printing technology, researchers have been able to help heal scarred heart tissue after a heart attack. Using a bio-printed cell patch, researchers have placed the patch on a mouse following a simulated heart attack. The researchers then saw a significant increase in functional heart capacity after just four weeks. This research study was published in Circulation Research, a journal published by the American Heart Association. Read more on the University of Minnesota website here.