PS192. The Pro-Proliferative and Anti-Apoptotic Micro-RNA 221 Is Decreased in Vulnerable Carotid Atherosclerotic Plaques

Abstract

MicroRNAs (miRs) are a class of recently discovered noncoding endogenous, small RNAs that negatively regulate gene expression. miR-221 is associated with vascular smooth muscle cell proliferation and inhibition of apoptosis. We aimed to determine whether miR-221 is decreased in acutely symptomatic as opposed to stable, asymptomatic carotid plaques. Relative changes in gene expression levels of miR-221 were compared using a commercial real-time PCR assay and the ΔΔCt method. All samples were run in duplicate; mean and standard error were calculated. One-way ANOVA with Tukey's test and Pearson's correlation were used to determine significance between groups. Levels of miR-221 were quantified from asymptomatic (n=16) and symptomatic (n=6) carotid plaques. In order to capture the acute state of plaque rupture, patients undergoing urgent CEA (n=11) for acute neurologic symptoms were included. The proportion of miR-221 in urgent compared to asymptomatic carotid plaques was reduced (.30±.16 vs. 1.00±.44, P = .039) (see figure). Moreover, a decreasing trend in miR-221 levels was noted in asymptomatic-to-symptomatic-to-urgent plaques (R=.43, P = .013). Carotid plaque levels of miR-221 are decreased in patients presenting with acute neurological symptoms compared to patients with asymptomatic carotid disease. As miR-221 levels are decreased in ruptured (urgent CEA) carotid plaques, we postulate that loss of miR-221 may be important in the transition of a stable to an unstable carotid atherosclerotic plaque and possible fibrous cap degradation and rupture. *:P = .039.