Circulating miRNA levels differ with respect to carotid plaque characteristics and symptom occurrence in patients with carotid artery stenosis and provide information on future cardiovascular events.

Introduction: Circulating microRNAs (miRNAs) levels are potentially important biomarkers and therapeutic targets of cerebral ischemic event (CIE) in patients with internal carotid artery stenosis (ICAS).

Aim: This prospective study investigated associations between circulating miRNAs and symptomatic and asymptomatic ICAS, carotid plaque morphology and future cardiovascular events.

Material and methods: Circulating miRNAs (miR-1-3p, miR-16-5p, miR-34a-5p, miR-124-3p, miR-133a-3p, miR-133b, miR-134-5p, miR-208b-3p, miR-375 and miR-499-5p) were analyzed in 92 consecutive patients with significant ICAS referred for revascularization. Group I comprised 65 subjects (41 males, age 69.3 ±9.7 years) with a recent CIE. Group II comprised 27 patients (15 males, age 68.2 ±8.4 years) with asymptomatic ICAS. The ICAS degree and plaque morphology was assessed by ultrasonography. The incidences of cardiovascular death (CVD), myocardial infarction (MI) and recurrent CIE (CVD/MI/CIE) were recorded prospectively (mean: 38.7 ±3.8 months).

Results: Groups II and I differed significantly in levels of miR-124-3p ( p = 0.036), miR-133a-3p ( p = 0.043) and miR-134-5p ( p = 0.02). Hypoechogenic, as compared to echogenic, plaques differed in levels of miR-124-3p ( p = 0.038), miR-34a-5p ( p = 0.006), miR-133b ( p = 0.048), miR-134-5p ( p = 0.045), and miR-375 ( p = 0.016), while calcified plaques differed in miR-16-5p ( p = 0.023). Ulcerated plaques showed higher levels of miR-1-3p ( p = 0.04) and miR-16-5p ( p = 0.003), while thrombotic plaques showed lower levels of miR-1-3p ( p = 0.032). CVD/MI/CIE occurred in 14 (15.5%) out of 90 follow-up patients. Multivariate Cox and ROC analysis showed associations between miR-1-3p and CVD (AUC = 0.634; HR = 4.84; 95% CI: 1.62-14.5; p = 0.005), MI (AUC = 0.743; HR = 7.8; 95% CI: 2.01-30.0; p = 0.003), and CVD/MI/CIE (AUC = 0.560; HR = 4.6; 95% CI: 1.61-13.1; p = 0.004), while miR-133b was associated with recurrent CIE (AUC = 0.581; HR = 2.25; 95% CI: 1.01-5.02; p = 0.047).

Conclusions: A significant difference in levels of selected miRNAs is observed in symptomatic vs. asymptomatic ICAS. Plaque morphology and structure is associated with change of miRNA levels. The expression of miR-1-3p may be a potential prognostic factor for future cardiovascular events.