Associations Of Circulating MiR-221、miR-622、miR-649Expression Levels With The Occurrence Of Ischemic Stroke

BackgroundAs our country entering an aging society gradually，Stroke incidence rate isrising about8.0%per year. Stroke has a very high morbidity and long-term disabilitywhich bring great suffering and heavey economic burden to patients and their families,and becomes a highlight public health problem in China. Ischemic stroke (IS),whichis the most common type of stroke, is a chronic diseasee with multiple factors by thecommon impact of heredity and environment. Although there are a great number ofrelevant research about IS, its pathogenesis has yet been completely elucidated.MicroRNA (miRNA) as a part of epigenetic gene regulation, more and morestudies show that miRNAs play an important role of happening and development incardiovascular and cerebrovascular diseases. Studies have shown that circulationmiR-221expression level decreased obviously in ischemic stroke patients. Existingstudies also show that miR-222takes part in the arterial plaque rupture and theprocess of angiogenesis, but not further confirmative research about the associationbetween miR-222and IS. According to the research group’s previous studies, wesuggested that the polymorphism of spleen tyrosine kinase (Syk) gene is closelyassociated with the susceptibility of IS in Chinese Han population. We usebioinformatics methods to screen the miRNAs, such as miR-622、miR-649, whichmay regulate Syk gene. And we also selected miR-221and miR-222which have beenreported in the literature. Base on comparing the expression level of these fourmiRNAs between IS patients and healthy control, we initially explore theaforementioned miRNAs’ role in IS.ObjectiveTo investigate the occurrence associated with ischemic stroke by detecting andcomparing the expression levels of miR-221、 miR-222、 miR-622、miR-649in theblood circulation between IS patients and healthy control subjects. To explore theassociations of miRNA with occurrence of IS, and further analyze the feasibility of those miRNAs as biomarkers for IS risk prediction.Subjects and methodsA case-control study with IS patients (n=52) and control group (n=52). Takingcirculation blood from cubital vein and extracted the total RNA from blood. Usingreal-time PCR to detect and compare the expression levels of miR-221、miR-222、miR-622、miR-649in the circulation between IS patients and healthy control subjects,to evaluate its significance in IS; SPSS21.0software for statistical was applied for thedate analysis. the continuous variables normality was tested by One-Sample K-S testmethod. The distribution of continuous variables was expressed with the mean±standard deviation (x±s), and Student’s t test was employed to test the differencebetween two independent sample. Mann-Whitney U and multiple independent samplerank sum test (H test) for skewed or unequal variance among two or more samples. Achi-square test was used for the comparison of categorical data. Logistic regressionwas used to analyze the correlation between miRNA expression levels and ischemicstroke occurs. ROC curve analysis was assessed the value of miRNAs in the IS riskprediction.ResultsCirculating miR-221and miR-622levels were(0.62±0.20)、(0.636±0.462)×10-3in ischemic stroke, was significantly lower than in control groups (0.88±0.16)、(1.571±0.325)×10-3,P＜0.05. And the expression level of miR-649(0.545±0.223)×10-3, significantly higher than in healthy controls (0.311±0.136)×10-3,P＜0.05. However, the expression level of miR-222does not have a statisticallysignificant difference between the two groups,P＞0.05. To analysis the correlationbetween miRNA expression levels and IS occurs by Logistic regression, and the ORfor miR-221was3.88, the miR-622was8.13, the miR-649was3.84, respectively. Onthe basis of the traditional risk factors, ROC curve analysis showed that the areaunder the curve (AUC) of miR-221was0.895, the miR-622was0.924, the miR-622was0.969, respectively. Conclusion1. We showed that circulating miR-221、 miR-221and miR-649levels weresignificantly associated with the occurrence of IS.2. Compared with the control group, miR-221and miR-622levels were markedlydown-regulated in IS, and miR-649had higher level in the patients, which may bebecome a new biomarkers for IS risk prediction.3. The miRNA can significantly improve the prediction model based on traditionalrisk factors.