Serum MicroRNA Levels And Its Clinical Significance In Patients With Transient Ischemic Attack

Transient ischemic attack(TIA)is an acute,temporary,reversible episode of neurologic dysfunction caused by focal cerebral ischemia.Patient with previous history of TIA indicates high risks of subsequent stroke associated with an increase in disability and mortality.In recent years,research on serum microRNAs(miRNAs)has become a hotspot because of their closely association with the pathogenesis and progression of ischemic cerebrovascular disease.However,the expression levels of serum miRNAs in TIA patients still need systematic and comprehensive analyses.The clinical values of serum miRNAs for the prediction and evaluation of stroke risk after TIA still need further investigation.Objective:To identify the distinctive miRNAs in TIA patients,several serum miRNAs levels were analyzed.To provide a new biomarker for the assessment and monitoring of TIA patients,the clinical values of these miRNAs and the serological markers of brain injury for the prediction and evaluation of stroke risk after TIA were investigated and compared.Methods:A total of 126 TIA patients and 44 healthy were enrolled.All patients were classified into three risk stratification groups by the ABCD3-1 score:low-risk(0-3,n=46),medium-risk(4-7,n=45),and high-risk(8-13.n=35).Then,13 candidate miRNAs associated with ischemic cerebrovascular disease,including miR-15b,miR-30a,miR-21,miR-29b,miR-181a,miR-124,miR-335,miR-146a,miR-499,miR-144,miR-208b,miR-215 and miR-23b,were analyzed by quantitative reverse-transcription PCR(qRT-PCR)in TIA patients and controls.Moreover,the the serological markers of brain injury were also determined,including lipoprotein associated phospholipase A2(Lp-PLA2),oxidized low density lipoprotein(ox-LDL),neuron specific enolase(NSE)and brain-derived neurotrophic factor(BDNF).Spearman rank correlation were performed to investigate the association among the serum miRNAs and serological markers of brain injury.Multivariate logistic regression analysis and receiver operating curve(ROC)analysis were performed to explore the clinical values of serum miRNAs and the serological markers of brain injury for the prediction and evaluation of stroke risk after TIA.Results:Part l:QRT-PCR validation showed that serum levels of miR-23b-3p,miR-181a-5p,miR-208b and miR-215 were significantly increased in TIA patients compared with controls(all P<0.05).Their levels were also significantly increased in each risk stratification group of TIA patients compared with the control group(all P<0.05).The significant positive correlation between these four miRNAs were found by Spearman's correlation analysis(all P<0.05).Part 2:Compared with controls,serum levels of Lp-PLA2,ox-LDL and NSE were significantly increased in TIA patients(all P<0.05).Their levels were also significantly increased in high-risk group of TIA patients compared with the control group(all P<0.05).Serum Lp-PLA2 levels were positively correlated with ox-LDL(r= 0.264,P=0.002)and NSE levels was positively correlated with BDNF(r=0.197,P= 0.041).Part 3:ROC analysis showed that the area under the curve(AUC)of miR-23b-3p,miR-181a-5p,miR-208b or miR-215 for differentiating TIA and controls was 0.784,0.795,0.768 and 0.779(all P<0.01),respectively.The AUC of the combination of miR-23b-3p,miR-181a-5p,miR-208b and miR-215 for differentiating TIA and controls was 0.812(P=0.001).The AUC of Lp-PLA2 and NSE for differentiating TIA and controls was 0.725 and 0.743(all P<0.05),respectively.The AUC of the combination of Lp-PLA2 and NSE for differentiating TIA and controls was 0.817(P=0.001).The AUC of the combination of these four miRNAs,Lp-PLA2 and NSE for differentiating TIA and controls was 0.925(P<0.001).Part 4:The three risk stratification groups of TIA and the control group was treated as a dependent four-category variable and the reference category was the control group.The univariate analysis suggested that high levels of miR-23b-3p,miR-208b and miR-2]5 may be independently correlated with the different stroke risk after TIA;high levels of Lp-PLA2,ox-LDL,NSE and BDNF may be independently correlated with the high stroke risk after TIA;high NSE levels may be also independently correlated with the medium and low stroke risk after TIA.After adjustment for age,gender,blood pressure and biochemical indexes,the multivariate analysis indicated that elevated miR-23b-3p levels were closely associated with the high and medium stroke risk after TIA;elevated miR-208b levels were closely associated with high stroke risk after TIA;elevated levels of Lp-PLA2,ox-LDL and NSE were closely associated with the high stroke risk after TIA;elevated levels of Lp-PLAi and NSE were closely associated with the medium and low stroke risk after TIA.Conclusions:Serum levels of miR-23b-3p,miR-181a-5p,miR-208b and miR-215 were significantly increased in TIA patients.These distinctive miRNAs may be served as the novel biomarkers for the prediction and evaluation of stroke risk after TIA,contributing to the assessment and monitoring of TIA patients.