The Relationship Between Mitochondrial DNA Content And Coronary Atherosclerotic Heart Disease

Objectives:To investigate the relationship between peripheral blood mtDNA content,the coronary atherosclerotic heart disease(CHD)and the severity of coronary stenotic lesions.Methods:A total of 420 inpatients who received coronary angiography(CAG)was consecutively enrolled in this study.They were divided into CHD group(321cases)and control group(99 cases)according to CAG results.A quantitative real-time PCR-based method was used to measure relative content of mtDNA in peripheral blood.Then we analyzed the relationship of mitochondrial DNA content and CHD.Results:1 Clinical features:Compared with the control group,the CHD group had more male patients[73.5%(236/321)vs 45.5%(45/99),P<0.001],the patients with hy p e r t e n s i o n and current smoking were significantly higher in CHD group than those in control group[62.3%(200/321)vs 49.5%(49/99);58.3%(187/321)vs 31.3%(31/99),P<0.05].2 Comparison of mtDNA content in CHD group and control group:2.1 Detection of mtDNA content by RT-PCR:mtDNA content in CHD group[0.42(0.28,0.65)]was significant lower than that in control group[0.79(0.62,1.05)].The difference has statistical significance(P<0.05).2.2 Multi-factor unconditioned Logistic regression analysis:after adjusted for confounding factors,the results suggest that the independent factors for the prevalence of CHD was male(OR=3.487,95%CI:2.062-5.894),hypertension(OR=1.742,95%CI:1.025-2.959),white blood cell count(OR=1.84,95%CI:1.072-3.159),fasting blood glucose(OR=1.774,95%CI:1.013-3.107)and mtDNA content(OR=0.202,95%CI:0.12-0.338).The mtDNA content was the protective factor.2.3 ROC curve analysis shows that area under the curve of mtDNA content was used in the diagnosis of CHD was 0.782(95%CI:0.728-0.835).The difference was statistically significant(P<0.001).The optimal cut-off point was 0.69,the sensitivity and specificity were 77.6%and 62.6%,respectively.3 The correlation of mtDNA content and vessel lesion counts:In accordance with vessel lesion counts,CHD patients were divided into single vessel lesion group,double vessel lesion group and three vessel lesion group.Subjects of the CHD group were divided into three groups according vessel lesion counts.mtDNA content in single vessel lesion group[0.5(0.32,0.78)],double vessel lesion group[0.44(0.31,0.65)],three vessel lesion group[0.37(0.25,0.49)]were lower than that in the control group[0.79(0.62,1.05)].With the increase of vessel lesion counts,mtDNA content was in a downward trend.The difference have statistical significance with compared between each two groups(P<0.001).4 The correlation of mtDNA content and the Gensini score:4.1 Based on the Gensini score results,all the subjects can be divided into four groups,<9 score(103 cases),9~<28 score(106 cases),28~<60 score(107 cases),>60 score(104 cases),respectively.The mtDNA content in<9group,9~<28 group,28~<60 group,>60 group were 0.81(0.63,1.05),0.56(0.38,0.81),0.4(0.27,0.72),0.36(0.23,0.43),respectively.The mtDNA content showed gradual decline in the four groups.The difference have statistical significance with compared between each two groups(P<0.001).4.2 Spearman correlation analysis showed a negative correlation between Gensini score and mtDNA content(r_s=-0.537,P<0.001).5 The correlations of mtDNA and clinical characteristics:mtDNA content was negatively correlated with male(r_s=-0.108),type 2 diabetes mellitus(r_s=-0.101),history of stroke(r_s=-0.134),current smoking(r_s=-0.13),the fasting blood glucose(r_s=-0.192),the differences were statistically significant(P<0.05).Conclusions:mtDNA content was significantly decreased in CHD group when compared with the control group,and an independent protective factor for CHD.mtDNA content showed significant differences with the change of vessel lesion counts and Gensini score.Gensini score was negatively correlated with mtDNA content,which can reflect the severity of coronary atherosclerosis.In conclusion,mtDNA is associated with CHD and the severity of coronary stenotic lesions.mtDNA may be used as biomarkers for the clinical diagnosis and evaluation of CHD.