Diverse associations observed between pregnancy complications and RBC or plasma folates determined by an in-house developed LC-MS/MS method

As folates are essential for embryonic development and growth, it is necessary to accurately determine the levels of folates in plasma and red blood cells (RBCs) for clinical intervention. The aims of this study were to develop and validate a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for quantitation of folates in plasma and RBCs and to examine the association between plasma and RBC folate concentrations and gestational diabetes mellitus (GDM), gestational hypertension (GH) and preeclampsia (PE). With the in-house developed LC-MS/MS, a retrospective cross-sectional study was conducted. The healthy pregnant women of first- (<i>n</i> = 147), second- (<i>n</i> = 84) and third-trimester (<i>n</i> = 141) or the women diagnosed with GDM (<i>n</i> = 84), GH (<i>n</i> = 58) or PE (<i>n</i> = 23), that were aged between 22 and 46 years old and registered at our institute, were subjected for measurement of folic acid (FA) and 5-methyltetrahydrofolate (5-MTHF), followed by appropriate statistical association analysis. The assay for simultaneous quantitation of FA and 5-MTHF in plasma and RBCs was linear, stable, with imprecision less than 15% and recoveries within ±10%. The lower limits of quantification for FA and 5-MTHF measurement in whole blood were 0.57 and 1.09 nmol/L, and in plasma were 0.5 and 1 nmol/L, respectively. In the association analysis, the patients with lower RBC folate level (&lt;906 nmol/L) presented higher risks of PE development (OR 4.861 [95% CI 1.411–16.505]) by logistic regression and restricted cubic spline (RCS) regression in a nonlinear fashion. In addition, higher level of plasma folates in pregnancy was significantly associated with GH risk but may be protective for the development of GDM. The in-house developed LC-MS/MS method for folates and metabolites in plasma or RBC showed satisfactory analytical performance for clinical application. Further, the levels of folates and metabolites were diversely associated with GDM, GH and PE development.

鉴于叶酸盐类（folates）对胚胎发育与生长至关重要，精准检测血浆与红细胞（red blood cells, RBCs）内的叶酸盐水平，对于临床干预而言不可或缺。本研究旨在建立并验证一种可定量检测血浆与红细胞内叶酸盐水平的液相色谱-串联质谱法（liquid chromatography-tandem mass spectrometry, LC-MS/MS），同时探究血浆与红细胞叶酸盐浓度与妊娠糖尿病（gestational diabetes mellitus, GDM）、妊娠高血压（gestational hypertension, GH）及子痫前期（preeclampsia, PE）之间的关联。
依托本实验室自主建立的LC-MS/MS方法，本研究开展了一项回顾性横断面研究。纳入年龄介于22~46岁、在本机构注册的受试者，包括孕早期（n=147）、孕中期（n=84）及孕晚期（n=141）的健康孕妇，以及确诊为GDM（n=84）、GH（n=58）或PE（n=23）的孕妇；所有受试者均接受叶酸（folic acid, FA）与5-甲基四氢叶酸（5-methyltetrahydrofolate, 5-MTHF）的检测，随后开展恰当的统计关联分析。
该可同时定量检测血浆与红细胞内FA与5-MTHF的检测方法线性良好、稳定性佳，精密度小于15%，回收率介于±10%之间。全血中FA与5-MTHF检测的定量下限分别为0.57 nmol/L与1.09 nmol/L，血浆中的定量下限则分别为0.5 nmol/L与1 nmol/L。
关联分析结果显示，经logistic回归与限制性立方样条（restricted cubic spline, RCS）回归分析后，红细胞叶酸盐水平较低（<906 nmol/L）的受试者发生PE的风险更高（比值比OR=4.861，95%置信区间CI：1.411~16.505），且该关联呈非线性特征。此外，妊娠期间血浆叶酸盐水平升高与GH风险升高显著相关，但或许可降低GDM的发生风险。
本实验室自主建立的可检测血浆或红细胞内叶酸盐及其代谢物的LC-MS/MS方法，具备良好的分析性能，可满足临床应用需求；进一步分析表明，叶酸盐及其代谢物水平与GDM、GH及PE的发生存在不同模式的关联。