Hernan A. Bazan, Chasity B. Coleman, Taylor Smith, W. Charles Sternbergh III, T. Cooper Woods
Ochsner Clinic, New Orleans, LA.
OBJECTIVES: 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.
METHODS: 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.
RESULTS: 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).
CONCLUSIONS: 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.
AUTHOR DISCLOSURES: H. A. Bazan, Nothing to disclose; C. B. Coleman, Nothing to disclose; T. Smith, Nothing to disclose; W. Sternbergh III, Nothing to disclose; T. Woods, Nothing to disclose.
*p = .039
Posted April 2012