Purpose: High LDL-cholesterol plasma levels constitute an independent risk factor for the pathogenesis of atherothrombotic cardiovascular (CV) disease. We aimed to study miRNAs, non-coding RNAs involved in post-transcriptional regulation of gene expression, in circulating exosomes as prognostic markers of future cardiovascular events.
Methods: Exosomes were isolated from platelet-free plasma (PFP) obtained from patients that suffered an ischemic event (n=42) within 3.0 ± 0.4 years post-sampling (CVE) and from age/treatment-matched patients (n=30) that did not have an event within the same time-frame (nCVE). Patients were from the SAFEHEART cohort and were fully clinically characterized. RNA from exosomes was obtained with the Exo-MiR extraction kit. miRNA profiling was performed using Megaplex pool Á microRNA arrays. Differentially expressed miRNAs were validated by RT-qPCR that was measured with Taqman miR Custom Array Cards.
Results: microRNA profiling revealed that 22 exosomal miRNAs were differentially expressed in CVE patients compared to nCVE patients. RT-qPCR validation confirmed that five of these miRNAs, including (miR-130b, miR-142-3p, miR-200c, miR-660, miR-744) are significantly increased in CVE patients. A ROC curve analysis of the predicted probabilities of this miRNA signature was calculated and an AUC of 0.795±0.069 [95%CI: 0.660-0.930] (p<0.001) for ischemic event presentation was obtained.
Conclusions: Exosomal miRNA signature could be used as a predictor of ischemic event presentation in hypercholesterolemic patients.