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Stem cells and the heart—the road ahead

After 20 years of research, pluripotent stem cells move to the fore to treat heart disease Heart disease is the primary cause of death worldwide, principally because the heart has minimal ability to regenerate muscle tissue. Myocardial infarction (heart attack) caused by coronary artery disease leads to heart muscle loss and replacement with scar tissue, and the heart's pumping ability is permanently reduced. Breakthroughs in stem cell biology in the 1990s and 2000s led to the hypothesis that heart muscle cells (cardiomyocytes) could be regenerated by transplanting stem cells or their derivatives. It has been ∼18 years since the first clinical trials of stem cell therapy for heart repair were initiated (1), mostly using adult cells. Although cell therapy is feasible and largely safe, randomized, controlled trials in patients show little consistent benefit from any of the treatments with adult-derived cells (2). In the meantime, pluripotent stem cells have produced bona fide heart muscle regeneration in animal studies and are emerging as leading candidates for human heart regeneration.