Abstract 15162: Plasma Levels of Circulating MicroRNAs Correlate with Coronary Plaque Burden as Assessed by Cardiac Computed Tomography
Background: MicroRNAs play a major role in angiogenesis. Though there is limited data on their clinical relevance, they potentially contribute to subclinical atherosclerosis. We investigated the correlation between coronary artery plaque burden assessed by Computed Tomography (CT) and plasma levels of endothelial miR-92a and miR-126 and smooth muscle miR-145 and miR-155 in patients without known coronary artery disease (CAD).
Methods: 33 patients (26 male, mean age 61±13y) underwent Dual Source-Computed Tomography for the exclusion of CAD. Plasma levels of miR-92a, miR-126, miR-145 and miR-155 were determined before scan, and miRNAs were quantified by real time-PCR. The levels were normalized to spiked c.elegans miRNA to control for the RNA extraction efficacy. CT data sets were quantified, classifying plaques by the predominantly present plaque type and by the number of plaques.
Results: MiR-92a, miR-126 and inflammation-related miR-155 were not significantly different in patient subgroups. However, there was a trend towards higher levels of miR-92 in patients with calcified plaques. Levels of miR-145 were significantly regulated: MiR-145 levels were reduced in patients with coronary plaques (0.09±0.07, n=24) if compared to patients without (0.23±0.18, n=9, p=0.006). Lowest miR-145 levels were detected in patients with non-calcified and mixed plaques (0.05±0.04, n=6 and 0.07±0.06, n=10). Moreover, the number of coronary plaques negatively influenced miR-145 levels (p=0.02 for >1 plaque vs. no plaque, Figure).
Conclusion: Coronary plaque identified by CT is associated with dysregulated levels of miRNAs. Endothelial and inflammation-derived miRNAs are not significantly changed, but miR-145, which regulates smooth muscle phenotypes, is reduced in subjects with atherosclerotic lesions. Since miR-145 is known to protect against atherosclerosis, the detection of suppressed miR-145 levels may help to identify vulnerable atherosclerotic lesions.
- © 2011 by American Heart Association, Inc.