Kühn Tilman, Rohrmann Sabine, Sookthai Disorn, Johnson Theron, Katzke Verena, Kaaks Rudolf, von Eckardstein Arnold, Müller Daniel
Clin Chem Lab Med. 2017 Feb 1;55(2):261-268. doi: 10.1515/cclm-2016-0374.
Circulating trimethylamine-N-oxide (TMAO) has been implicated in the development of cardiovascular and chronic kidney diseases (CKD). However, while higher TMAO levels have been associated with increased risks of cardiovascular or renal events in first prospective studies, it remained unclear how much plasma TMAO concentrations vary over time.
We measured fasting plasma levels of TMAO and two of its precursors, betaine and choline by LC-MS, in two samples of 100 participants of the European Investigation into Cancer and Nutrition (EPIC)-Heidelberg study (age range: 47-80 years, 50% female) that were collected 1 year apart, and assessed their intra-individual variation by Spearman's correlation coefficients (ρ).
Correlations of metabolite concentrations over 1 year were at ρ=0.29 (p=0.003) for TMAO, ρ=0.81 (p<0.001) for betaine, and ρ=0.61 (p<0.001) for choline. Plasma levels of TMAO were not significantly associated with food intake, lifestyle factors, or routine biochemistry parameters such as C-reactive protein (CRP), low-density lipoprotein (LDL)-cholesterol, or creatinine.
In contrast to fasting plasma concentrations of betaine and choline, concentrations of TMAO were more strongly affected by intra-individual variation over 1 year in adults from the general population. The modest correlation of TMAO levels over time should be considered when interpreting associations between TMAO levels and disease endpoints.
循环中的氧化三甲胺（TMAO）与心血管疾病和慢性肾脏病（CKD）的发生有关。然而，虽然在最初的前瞻性研究中较高的TMAO水平与心血管或肾脏事件风险增加相关，但血浆TMAO浓度随时间的变化情况仍不清楚。
我们通过液相色谱-质谱法（LC-MS）测量了欧洲癌症与营养调查（EPIC）-海德堡研究中100名参与者（年龄范围：47 - 80岁，50%为女性）的两个样本中TMAO及其两种前体物质甜菜碱和胆碱的空腹血浆水平，这两个样本相隔1年采集，并通过斯皮尔曼相关系数（ρ）评估其个体内变异。
1年内代谢物浓度的相关性，TMAO为ρ = 0.29（p = 0.003），甜菜碱为ρ = 0.81（p < 0.001），胆碱为ρ = 0.61（p < 0.001）。TMAO的血浆水平与食物摄入量、生活方式因素或常规生化参数如C反应蛋白（CRP）、低密度脂蛋白（LDL）胆固醇或肌酐无显著关联。
与甜菜碱和胆碱的空腹血浆浓度不同，一般人群中成年人的TMAO浓度在1年内受个体内变异的影响更大。在解释TMAO水平与疾病终点之间的关联时，应考虑TMAO水平随时间的适度相关性。
