From the Technology Review: "Treating embryonic cells from mice with a cocktail of proteins triggers production of new heart-muscle cells ... Working with mouse embryos about a week old, [researchers] discovered that a trio of proteins - including a pair of transcription factors and a protein that helps loosen tightly wound DNA - could direct certain embryonic cells to form cardiac-muscle cells, called cardiomyocytes. These cells not only produced proteins characteristic of early heart cells, but they eventually started to beat. ... Human trials of cell therapies for heart disease, which have mostly used stem cells derived from a patient's own blood, have yielded mixed results. It may be that transplanting cardiac myocytes rather than undifferentiated cells will prove more effective. ... we'd like to be able to make cardiac myocytes from any cell type. That would be the ideal therapy - to be able to turn those scar-tissue cells into cardiac myocytes and restore the function that's been lost ... The dream is to be able to take a skin cell or a cardiac fibroblast, any kind of cell a person has a lot to spare, and turn those into myocytes."