Adult bone marrow-derived cells for cardiac repair: A systematic review and meta-analysis

Background: The results from small clinical studies suggest that therapy with adult bone marrow (BM)-derived cells (BMCs) reduces infarct size and improves left ventricular function and perfusion. However, the effects of BMC transplantation in patients with ischemic heart disease remains unclear. Methods: We searched MEDLINE, EMBASE, Science Citation Index, CINAHL (Cumulative Index to Nursing and Allied Health), and the Cochrane Central Register of Controlled Trials (CENTRAL) (through July 2006) for randomized controlled trials and cohort studies of BMC transplantation to treat ischemic heart disease. We conducted a random-effects meta-analysis across eligible studies measuring the same outcomes. Results: Eighteen studies (N=999 patients) were eligible. The adult BMCs included BM mononuclear cells, BM mesenchymal stem cells, and BM-derived circulating progenitor cells. Compared with controls, BMC transplantation improved left ventricular ejection fraction (pooled difference, 3.66%; 95% confidence interval [CI], 1.93% to 5.40%; P<.001); reduced infarct scar size (?5.49%; 95% CI, ?9.10% to ?1.88%; P=.003); and reduced left ventricular end-systolic volume (?4.80 mL; 95% CI, ?8.20 to ?1.41 mL; P=.006). Conclusions: The available evidence suggests that BMC transplantation is associated with modest improvements in physiologic and anatomic parameters in patients with both acute myocardial infarction and chronic ischemic heart disease, above and beyond conventional therapy. Therapy with BMCs seems safe. These results support conducting large randomized trials to evaluate the impact of BMC therapy vs the standard of care on patient-important outcomes.