Ongoing work in regenerative medicine: "scientists have succeeded in taking skin cells from heart failure patients and reprogramming them to transform into healthy, new heart muscle cells that are capable of integrating with existing heart tissue. The research [opens] up the prospect of treating heart failure patients with their own, human-induced pluripotent stem cells (hiPSCs) to repair their damaged hearts. As the reprogrammed cells would be derived from the patients themselves, this could avoid the problem of the patients' immune systems rejecting the cells as 'foreign'. ... Recent advances in stem cell biology and tissue engineering have enabled researchers to consider ways of restoring and repairing damaged heart muscle with new cells, but a major problem has been the lack of good sources of human heart muscle cells and the problem of rejection by the immune system. Recent studies have shown that it is possible to derive hiPSCs from young and healthy people and that these are capable of transforming into heart cells. However, it has not been shown that hiPSCs could be obtained from elderly and diseased patients. In addition, until now researchers have not been able to show that heart cells created from hiPSCs could integrate with existing heart tissue. [Researchers] took skin cells from two male heart failure patients (aged 51 and 61) and reprogrammed them by delivering three genes or 'transcription factors' ... Crucially, this reprogramming cocktail did not include a transcription factor called c-Myc, which has been used for creating stem cells but which is a known cancer-causing gene. ... The resulting hiPSCs were able to differentiate to become heart muscle cells (cardiomyocytes) just as effectively as hiPSCs that had been developed from healthy, young volunteers who acted as controls for this study. Then the researchers were able to make the cardiomyocytes develop into heart muscle tissue, which they cultured together with pre-existing cardiac tissue. Within 24-48 hours the tissues were beating together. ... The tissue was behaving like a tiny microscopic cardiac tissue comprised of approximately 1000 cells in each beating area. ... Finally, the new tissue was transplanted into healthy rat hearts and the researchers found that the grafted tissue started to establish connections with the cells in the host tissue."