分支DNA技术检测血浆游离DNA方法的建立及在急性心肌梗死患者中的初步应用简

 目的 采用分支DNA（bDNA）信号放大定量技术建立检测血中游离DNA（cf-DNA）—ALU基因表达的方法并分析其在急性心肌梗死（AMI）患者血浆中的含量。方法 根据ALU基因序列特点设计探针，建立检测血ALU的bDNA信号放大定量方法，并对其线性、灵敏度及精密度进行评价；根据标准曲线计算出AMI患者血浆中ALU的含量，并与肌钙蛋白I（cTnI）、肌酸激酶同功酶MB（CK-MB）和肌红蛋白（MYO）进行相关性分析。结果 线性范围为0~400 ng/mL，相关系数为0.99，批内变异系数（CV）为7.85%~11.75%，批间CV为10.05%~14.32%。AMI患者和健康对照组血浆ALU的含量分别是中位数4223 ng/mL和118 ng/mL，四分位数区间2285~7864 ng/mL和81~218 ng/mL（P＜0.001），提示AMI患者血浆ALU含量上调，但与cTnI、CK-MB和MYO浓度无相关性。ALU的ROC曲线下面积为0.99，敏感度98.8%，特异性100.0%。结论 本研究建立的检测方法具有灵敏、重复性好等优点，升高的ALU含量与AMI存在一定相关性。

Establishment and primary application of a ALU-based bDNA for the detection of plasma circulating free DNA in acute myocardial infarction

Objective To establish a ALU-based branched DNA (bDNA) method for detection of human plasma circulating free DNA (cf-DNA) and investigate its concentration in acute myocardial infarction (AMI). Methods Based on the sequence of ALU, a bDNA method was established, Liner, sensitivity and reproducibility were evaluated; according to the standard curve created, the concentration of ALU in AMI were determined and the relationship of cf-DNA concentrations with cardiac enzymes were presented. Results The linear rang was 0-400 ng/mL, the coefficient correlation was 0.99，the intra-assay coefficient variation was 7.85%-11.75%, the inter-assay coefficient variation was10.05%-14.32%. The concentration of ALU in AMI and healthy controls were 4223 ng/mL and 118 ng/mL (P＜0.001) respectively indicating that ALU concentration was increased in AMI. No correlation was found among ALU and cardiac enzymes. The area under ROC was 0.99, the sensitivity was 98.8% and the specificity was 100.0%. Conclusions The ALU-based bDNA method is sensitive and reproductive; cf-DNA concentration is associated with AMI.