Cardiologists are increasingly using adult stem cells in clinical trials to repair hearts following heart attacks, but no one has understood how the therapy actually works. Now, in animal experiments, researchers at The University of Texas M. D. Anderson Cancer Center have deconstructed the process, describing how the stem cells fuse with heart muscle cells to create new cells that repopulate the ailing organ. In a paper posted at Online First of the journal Circulation Research, investigators found that this fusion is only possible if two cell adhesion proteins that stick to each other like Velcro are available to attach...