Evolving cell-based therapies for heart failure patients.

Heart failure (HF) represents the only cardiovascular disease (CVD) whose incidence continues to rise in the developed world. With recent advances in device and drug therapies, the prognosis is improving. Nevertheless, the mortality associated with HF remains high, with more than 50% of patients dying within 5 years after initial diagnosis. The loss of cardiac cells is a major contributor to the development and progression of HF, thus therapeutic interventions to repair or regenerate lost cardiac cells hold tremendous promise. During the past several years, cell-based therapy for CVD has moved at a rapid pace from animal studies to clinical trials. To date, populations enrolled in cell-based therapy trials have comprised patients with coronary artery disease and myocardial infarction, with a limited number of trials conducted in patients with congestive HF. Also, most trials have used autologous skeletal myoblasts or bone marrow cells (whole bone marrow or subpopulations). The outcomes from these studies have been largely mixed, ranging from clear beneficial effects of cell therapy to no observed improvement, although all trials demonstrated a reasonable degree of safety, at least within the study period. Several critical issues, such as the type of cells, number of cells, timing, delivery methods, and the mechanisms of action involved, remain to be elucidated. This article reviews the current status of the emerging field of cell-based therapies for CVD, with particular focus on HF treatment.