Another example of progress in tissue engineering from the Boston Globe: "researchers have created a strip of pulsing heart muscle from mouse embryonic stem cells, a step toward the eventual goal of growing replacement parts for hearts damaged by cardiovascular disease. ... I think over the last five years or so, we've made great progress in being able to guide stem cells into whatever cell type we want, in this case the heart ... For years, scientists have been able to turn embryonic stem cells into a variety of heart cells, producing dramatic videos of cells beating in a dish. In the new work, [biologists] first isolated a progenitor cell that would only give rise to ventricular muscle cells - the working muscle that drives blood around the body, and the tissue that is damaged during a heart attack. Then, collaborating with biomedical engineers, they seeded those cells on a thin film that had been engineered in such a way that it encouraged them to begin to form cardiac muscle." This doesn't seem quite as far along as some other groups, and it's still far behind what can be done with decellularization and a donor organ - but progess is underway.