The Study Of Circulating MicroRNA In The Early Diagnosis Of Acute Myocardial Infarction

Aims:More and more studies have shown that microRNAs are present in the blood of human and are considered as a new biomarker for the diagnosis of disease.To investigate the possibility of circulating microRNAs as the biomarkers for the early diagnosis and prognosis of acute myocardial infarction by detecting the variability expression of miR-208,miR-214 and miR-21 in serum between acute myocardial infarction patient and healthy control with real-time polymerase chain reaction(PCR)。To lay the foundation for the further experimental study and gene therapy of miRNA gene in the process of acute myocardial infarction.Methods:Blood samples for miRNA detection were collected from 38 AMI (without any treatment),25 non-AMI patients with chest disress and pain,20 healthy volunteers admitted to the primary affliated hospital.Total RNA in plasm were isolated by using TRIzol following the instructions.MiRNAs were quantified by using quantitative reverse transcriptase-polymerase chain reaction(qRT-PCR) assay.The degree of coronary artery disease is divided according to Gensini score system:A group of 11 patient(total score<30 points),B group 15 patient(total score 31-90 points),C group,12 patients(total score>90 points).To analyse the relationship between the expression of miRNA in serum of acute myocardial infaction as healthy group and the severity of coronary artery, detect the change of myocardial injury markers CK-MB simultaneously, and make the correlation analysis for detected miRNA and CK-MB.Result:(1),miR-208,miR-214,miR-21 were detected in serum with real-time quantitative PCR.miR-208 and miR-214 are up-regulated while miR-21 is down-regulated in serum of acute myocardial infarction contrast with Control group (Coronary Heart Disease without AMI and healthy group),(P<0.05).(2),miR-208 and miR-214 are up-regulated in CHD contrast with health group while no significant difference(P>0.05),miR-21 is down-regulated(P<0.05). (3),The expression of miRNA in the group of low score is significantly lower than the high group according to Gensini.(P<0.05).(4),The expression level of miR-208 and miR-214 is positively correlated with CK-MB(r=0.81,073).,but the expression of miR-21 is negatively correlated with CK-MB(r=0.6).Conclusion:Circulating microRNA molecules express abnormally in the serum of patients with Acute Myocardial infarction,and there is a poor correlation between the expression of target miRNA,gender and age.It is revealed that the miRNA in serum may be a new candidate biomarkers for the early diagnosis of AMI.The analysisi show that the expression of miRNA between AMI group and healthy group is positively correlated with the severity of coronary artery with paried-rank test..In this study,the selected cardiac-specific miRNA genes miR-208,miR-214 were verified to be over-expressed with the quantitative RT-PCR technique. The experimental results show that cell-specific miRNA can be used as a new biomarkers for the early diagonosis,treatment and prognosis of clinical disease.The quantitative RT-PCR technique will provide an impetus for serum sample in target discovery studies.These results suggest that specific miRNA myocardial cells can be used as a new class of biomarkers for early diagnosis of clinical disease and the assessment of prognosis.