Expression of miRNA-33 and miRNA-155 in symptomatic and asymptomatic carotid artery stenosis

Background: The aim of this study was to evaluate miRNA-33 and miRNA-155 expression in Peripheral Blood Mononuclear Cells (PBMC) and carotid specimens of patients affected by Critical Carotid Artery stenosis (CAS). Material and Methods: We selected 17 asymptomatic (CAS-A group) and 10 symptomatic (CAS-S group) patients with CAS. Ten patients with traditional cardiovascular risk factors (RF group), matched for age and sex, were used as control group. Results: A significant increase in miRNA-33 expression was observed both in peripheral blood and in carotid specimens of CAS-A patients (p 0.04) in comparison with CAS-S and RF, whereas no significant difference were found among the groups regarding miRNA-155 expression both in peripheral blood and in carotid specimens. Conclusions: This is to our knowledge the first report on miRNAs expression in human PBMCs from CAS patients. Results of this study suggest that miRNA-33 in involved in the process underling plaque formation and growth, but not is plaque instability and ischemic brain damage, whereas miRNA-155 is expressed during all the phases of atherosclerotic disease.