BACKGROUND: MicroRNA (miRNA) expression profiles in endothelial progenitor cells 
(EPCs) contribute to EPC dysfunction in patients suffering from coronary artery 
disease. However, it remains unclear whether miRNA expression in EPCs is 
associated with the prognosis of chronic heart failure (CHF) secondary to 
ischemic cardiomyopathy (ICM) or non-ischemic cardiomyopathy (NICM).
METHODS AND RESULTS: One hundred six patients with CHF (55 ICM and 51 NICM) and 
30 healthy controls were followed until the end of 24 months or when the end 
point was obtained (cardiovascular death). The miRNA expression profile was 
analyzed by TaqMan Human MicroRNA Array Set v2.0 in 30 randomly assigned samples 
(ICM=10, NICM=10, and healthy controls=10). During the 24-month follow-up, 26 
patients died from cardiovascular disease. Sixteen miRNAs (miR-126, miR-508-5p, 
miR-34a, miR-210, miR-490-3p, miR-513-5p, miR-517c, miR-518e, miR-589, miR-220c, 
miR-200a*, miR-186*, miR-7i*, miR-200b*, miR-595, and miR-662) were found to be 
differentially expressed between ICM and NICM patients. Survival analysis showed 
that miR-126 and miR-508-5p levels in EPCs were independent prognostic factors 
(P=0.003; HR (hazard ratio): 0.19; 95% CI (confidence intervals): 0.06-0.58, 
P=0.002; HR: 2.292; 95% CI: 1.37-3.84) for the outcome of ICM or NICM patients 
with CHF. Pathway enrichment analysis showed that the angiogenesis pathway was 
the most likely pathway regulated by miR-126 and miR-508-5p.
CONCLUSIONS: The miRNAs miR-126 and miR-508-5p are associated with the outcome 
of ICM and NICM patients with CHF. These two miRNAs could be useful in the 
diagnosis of CHF patients, and might provide novel targets for prevention and 
treatment of CHF.