Mending broken hearts

Human cardiac disease involving a disruption of blood flow, for example, in myocardial infarction, initiates a process in which heart muscle cells (the myocardium) die. Natural repair mechanisms do exist, including an enlargement of the heart, an increase in the number of cells present, and the traveling of bone-marrow–derived stem cells (BMCs) to effect some repair, but none are effective in the long term. To effect additional repair, harvesting and direct injection of BMCs and mesenchymal stems cells (MSCs) into ischemic myocardium has been undertaken. This has met with partial success and is partly explained by the poor viability of the transplanted cells. In the August 10 Nature Medicine, Abeel A. Mangi and colleagues at Brigham and Women's Hospital and Harvard Medical School genetically engineered MSCs designed to overcome previous problems with cell death during transplantation into infarcted hearts (Nature Medicine, DOI:10.1038/nm912, August 10, 2003).

Mangi et al. grew large ...