Effect of cardiac rehabilitation on circulating microRNA expression in heart failure: a preliminary study.

OBJECTIVES: There are benefits of exercise-based cardiac rehabilitation (CR) in patients with heart failure (HF), but their underlying molecular mechanisms remain elusive. The effect of CR on the expression profile of circulating microRNAs (miRNAs), which are short noncoding RNAs that regulate posttranscriptional expression of target genes, is unknown. If miRNAs respond to changes following CR for HF, then serum profiling of miRNAs may reveal cardioprotective mechanisms of CR. METHODS: This study enrolled three hospitalized patients with progressed systolic HF and three normal volunteer controls. In patients, CR was initiated after improvement of HF, which included 2 weeks of bicycle ergometer and resistance exercises. Genome-wide expression profiling of circulating miRNAs was performed using microarrays for the patients (mean±SD age, 60.0±12.2 years) and controls (58.7±0.58 years). Circulating miRNA expression profiles were compared between patients with HF before and after CR and the controls. RESULTS: Expression levels of two miRNAs were significantly different in patients before CR compared with controls and patients after CR. The expression of hsa-miR-125b-1-3p was significantly downregulated and that of hsa-miR-1290 was significantly upregulated in patients before CR. CONCLUSIONS: When performing CR, expression of certain circulating miRNAs in patients with HF is restored to nonpathological levels. The benefits of CR for HF may result from regulation of miRNAs through multiple effects of gene expression.