Repair of the damaged heart by bone marrow cells: from experimental evidence to clinical hope.

Heart failure remains the leading cause of death in developed countries in spite of improvements in medical and surgical treatments. However, recent observations in experimental studies that bone marrow cells may repair cardiac tissue have offered renewed hopes for the treatment of heart failure. This optimism is further supported by encouraging results from some clinical trials, although the degree of benefits, the underlying mechanisms, and the cell types involved remain to be elucidated. This review summarizes the relevant experimental and clinical studies supporting the use of bone marrow cells in myocardial repair, as well as the controversies and challenges encountered.