Low serum miR-320b expression as a novel indicator of carotid atherosclerosis

We aimed to investigate correlation of carotid plaque with serum microRNA level and provide a potential mechanism for ischemic stroke prevention. Fasting serum was obtained from 177 patients with carotid plaques diagnosed using B ultrasound and 155 healthy subjects for RNA extraction and measurement of glucose, lipid and related biochemical indices. microRNAs level was assayed using microarray, validated using real-time PCR and statistically analyzed for their correlation with relevant clinical information. Statistical analyses showed significant differences between control and plaque groups in age, smoking history, and histories of cerebrovascular diseases, blood pressure, diabetes and coronary diseases. Patients in plaque group had significantly higher LDL-C level but significantly lower miR-320b level than healthy subjects. The P50 (P₂₅-P₇₅) of miR-320b was 2.38 (1.46-3.80) in control group and 1.20 (0.80-2.01) in plaque group (P=0.000), as well as 1.39 (0.83-2.08) in stable plaque group and 0.77 (0.590.99) in vulnerable plaque group (P=0.000). The area under the ROC curve of traditional factors, miR320b with traditional factors, traditional factors with plaque diameter, and traditional factors with IMT for patients with carotid plaques was 0.710, 0.834, 0.826 and 0.808, respectively. This study suggests that miR-320b is a specific serum marker of carotid atherosclerosis and vulnerable plaque, and its combination with traditional factors is the best means for diagnosis of cerebrovascular diseases. The carotid atherosclerosis complicated with vulnerable plaque is a high risk factor for cerebral infarction. B-ultrasound examination combined with serum miR-320b expression and traditional indices could be used to predict subjects with high-risk for ischemic stroke.