E-Mail IMAGE: Researchers from the University of Tsukuba showed that cardiac scar tissue (fibroblasts) can be directly reprogrammed to heart muscle cells (cardiomyocytes) in mice. By treating mice post-heart attack with a... view more Credit: University of Tsukuba Tsukuba, Japan - It is estimated that during a heart attack, one billion cells in the heart are lost. In the wake of the heart attack, the lost tissue is replaced by scar tissue, which can lead to heart failure, arrhythmia and death. In a new study, researchers from the University of Tsukuba have shown how cells in the scar tissue can be converted to heart muscle cells, effectively regenerating the injured heart.