Fixing a broken heart with bone

The use of bone marrow-derived stem cells from matched donors to reconstitute the immune system in patients with certain types of leukemia is now standard practice, and there is great interest in using stem cells to treat other human diseases. This approach received a major boost with the demonstration by Donald Orlic (New York Medical College, NY, USA) and colleagues that bone marrow stem cells delivered locally into an infarcted heart resulted in myocardial regeneration and a recovery in cardiac function in a mouse model of coronary heart disease. Stem cells from the bone marrow appeared to differentiate into cardiomyocytes, smooth muscle cells and endothelial cells, demonstrating the multipotent nature of the bone marrow cells used. Importantly, the infarct size was reduced, limiting the amount of scar tissue remaining. This study raises the possibility that heart-attack victims could be treated with stem cells from their own bone marrow, thus eliminating concerns about stem-cell rejection. Nature (2001) 410, 701–705. LON