The lack of precise biomarkers that identify patients at risk for myocardial injury and stable angina delays administration of optimal therapy. Hence, the search for noninvasive biomarkers that could accurately stratify patients with impending heart attack, from patients with stable coronary artery disease (CAD), is urgently needed in the clinic. Herein, we performed comparative quantitative proteomics on whole plasma sampled from patients with stable angina (NMI), acute myocardial infarction (MI), and healthy control subjects (Ctrl). We detected a total of 371 proteins with high confidence (FDR < 1%, p < 0.05) including 53 preliminary biomarkers that displayed ≥2-fold modulated expression in patients with CAD (27 associated with atherosclerotic stable angina, 26 with myocardial injury). In the verification phase, we used label-free LC–MRM-MS-based targeted method to verify the preliminary biomarkers in pooled plasma, excluded peptides that were poorly distinguished from background, and performed further validation of the remaining candidates in 49 individual plasma samples. Using this approach, we identified a final panel of eight novel candidate biomarkers that were significantly modulated in CAD (p < 0.05) including proteins associated with atherosclerotic stable angina that were implicated in endothelial dysfunction (F10 and MST1), proteins associated with myocardial injury reportedly involved in plaque destabilization (SERPINA3, CPN2, LUM), and in tissue protection/repair mechanisms (ORM2, ACTG1, NAGLU). Taken together, our data showed that candidate biomarkers with potential diagnostic values can be successfully detected in nondepleted human plasma using an iTRAQ/MRM-based discovery-validation approach and demonstrated the plausible clinical utility of the proposed panel in discriminating atherosclerotic stable angina from myocardial injury in the studied cohort.

中文翻译：

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通过基于iTRAQ / MRM的方法鉴定出的一组候选血浆生物标志物，可将心肌损伤与稳定型心绞痛区分开来

缺乏确定有心肌损伤风险和稳定型心绞痛患者的精确生物标志物，这延迟了最佳治疗的实施。因此，在临床上迫切需要从稳定的冠状动脉疾病（CAD）患者中寻找可以准确地将即将发作的心脏病患者分层的非侵入性生物标志物。在本文中，我们对从稳定型心绞痛（NMI），急性心肌梗塞（MI）和健康对照受试者（Ctrl）采集的全血浆样品进行了比较定量蛋白质组学。我们检测到总共371种蛋白质，具有很高的置信度（FDR <1％，p<0.05）包括53项在CAD患者中显示≥2倍调节表达的初步生物标志物（27例与动脉粥样硬化稳定型心绞痛相关，26例心肌损伤）。在验证阶段，我们使用了无标记的基于LC–MRM-MS的靶向方法，以验证合并血浆中的初步生物标志物，排除了与背景分辨差的肽，并对49个单独血浆样品中的其余候选物进行了进一步验证。使用这种方法，我们确定了由CAD显着调节的8种新的候选生物标志物的最终面板（p<0.05），包括与内皮功能障碍有关的与动脉粥样硬化稳定型心绞痛有关的蛋白质（F10和MST1），与心肌损伤有关的蛋白质据报道与斑块失稳有关（SERPINA3，CPN2，LUM）和组织保护/修复机制（ORM2， ACTG1，NAGLU）。综上所述，我们的数据表明，使用基于iTRAQ / MRM的发现-验证方法，可以在未消耗的人类血浆中成功检测出具有潜在诊断价值的候选生物标志物，并证明了拟议中的该小组在将动脉粥样硬化稳定型心绞痛与心肌损伤相鉴别方面的可行性在研究的队列中。