Cell therapy for cardiovascular disease: what cells, what diseases and for whom?

Experimental and human data suggesting progenitor cells possess the capacity to regenerate tissue and augment repair in injured organs has generated widespread interest in the basic research and clinical communities. Nowhere have these findings been more tantalizing than in human cardiovascular disease, in which vasculogenesis and myocardial regeneration logically and understandably remain as attractive therapeutic targets. Burgeoning experimental evidence attests to the proangiogenic, vasculogenic and tissue reparative capabilities of a broad range of progenitor cells derived from the bone marrow, circulation and a number of other tissues in vivo. Studies demonstrating the most apparent therapeutic success are those implicated in revascularization and repair of acute or chronically ischemic tissues in the heart and the peripheral vascular system. Numerous small clinical trials have yielded promising preliminary results without clear evidence of a superiority for a specific cell type or clinical disease entity as the most suitable target for cell therapy. This review will evaluate the scientific rationale for use of a specific cell or cells, the cardiovascular disease states most appropriate for targeted cell therapy, and the patient-specific barriers to therapeutic success, including emerging hurdles such as cardiovascular risk factors and comorbidities in eligible subjects.