I don't think they can. The reason they use the "decellularized heart" is because they need a scaffold for the cells to grow on. This has basically been what's

I don't think they can. The reason they use the "decellularized heart" is because they need a scaffold for the cells to grow on. This has basically been what's holding back growing organs. They may, however, be able to use another mammal's heart for the scaffold, such as a cow or pig, with the help of some genetic engineering. I read something a while back about a group of scientists that genetically engineered a pig so that its organs could be transplanted into humans. If I remember correctly, a pig's organs have a salty layer on them or something making them incompatible with humans.