Wang Zeneng, Levison Bruce S, Hazen Jennie E, Donahue Lillian, Li Xin-Min, Hazen Stanley L
Department of Cellular & Molecular Medicine, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195, USA.
Department of Cellular & Molecular Medicine, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195, USA.
Anal Biochem. 2014 Jun 15;455:35-40. doi: 10.1016/j.ab.2014.03.016. Epub 2014 Apr 1.
Trimethylamine-N-oxide (TMAO) levels in blood predict future risk for major adverse cardiac events including myocardial infarction, stroke, and death. Thus, the rapid determination of circulating TMAO concentration is of clinical interest. Here we report a method to measure TMAO in biological matrices by stable isotope dilution liquid chromatography tandem mass spectrometry (LC/MS/MS) with lower and upper limits of quantification of 0.05 and >200μM, respectively. Spike and recovery studies demonstrate an accuracy at low (0.5μM), mid (5μM), and high (100μM) levels of 98.2, 97.3, and 101.6%, respectively. Additional assay performance metrics include intraday and interday coefficients of variance of <6.4 and <9.9%, respectively, across the range of TMAO levels. Stability studies reveal that TMAO in plasma is stable both during storage at -80°C for 5years and to multiple freeze thaw cycles. Fasting plasma normal range studies among apparently healthy subjects (n=349) show a range of 0.73-126μM, median (interquartile range) levels of 3.45 (2.25-5.79)μM, and increasing values with age. The LC/MS/MS-based assay reported should be of value for further studies evaluating TMAO as a risk marker and for examining the effect of dietary, pharmacologic, and environmental factors on TMAO levels.
血液中的氧化三甲胺（TMAO）水平可预测未来发生重大不良心脏事件（包括心肌梗死、中风和死亡）的风险。因此，快速测定循环中的TMAO浓度具有临床意义。在此，我们报告一种通过稳定同位素稀释液相色谱串联质谱法（LC/MS/MS）测量生物基质中TMAO的方法，其定量下限和上限分别为0.05和>200μM。加标回收率研究表明，在低（0.5μM）、中（5μM）和高（100μM）水平下的准确度分别为98.2%、97.3%和101.6%。其他分析性能指标包括在TMAO水平范围内，日内和日间变异系数分别<6.4%和<9.9%。稳定性研究表明，血浆中的TMAO在-80°C储存5年以及多次冻融循环过程中均保持稳定。对明显健康的受试者（n = 349）进行的空腹血浆正常范围研究显示，范围为0.73 - 126μM，中位数（四分位间距）水平为3.45（2.25 - 5.79）μM，且随年龄增长而升高。所报道基于LC/MS/MS的分析方法对于进一步评估TMAO作为风险标志物以及研究饮食、药理和环境因素对TMAO水平的影响的研究应具有价值。
