BackgroundCerebrospinal fluid (CSF) metabolomic investigations are a powerful tool for studying neurometabolic diseases. We aimed to assess the effect of CSF contamination with blood on the concentrations of selected biomarkers.MethodsCSF samples were spiked in duplicate with increasing volumes of whole blood under two conditions: (A) pooled CSF spiked with fresh whole blood and frozen to cause red blood cell (RBC) lysis; (B) pooled CSF spiked with fresh blood and centrifuged (the supernatant with no RBCs was frozen until the moment of analysis). CSF concentrations of amino acids, biogenic amines, pterins, and vitamins were analysed by HPLC coupled with tandem mass spectrometry, electrochemical and fluorescence detection.ResultsAspartate, glutamate, taurine, ornithine, glycine, citrulline, pyridoxal 5´-phosphate, 5-methyltetrahydrofolate, and thiamine showed higher values when RBCs were lysed when compared with those of CSF with no RBC, while arginine, 5-hydroxyindoleacetic and homovanillic acids showed lower values. When RBCs were removed from CSF, only some amino acids, thiamine and pyridoxal 5´-phosphate showed moderately higher values when compared with the non-spiked CSF sample.ConclusionsCSF-targeted metabolomic analysis is feasible even when substantial RBC contamination of CSF has occurred since CSF centrifugation to remove RBC prior to freezing eliminated most of the interferences observed.

中文翻译：

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脑脊液血液污染对氨基酸、生物胺、蝶呤和维生素的影响

背景脑脊液 (CSF) 代谢组学研究是研究神经代谢疾病的有力工具。我们的目的是评估血液中 CSF 污染对所选生物标志物浓度的影响。 方法 在两种条件下，随着全血体积的增加，CSF 样品一式两份加入：(A) 混合 CSF 加入新鲜全血并冷冻以产生红血细胞 (RBC) 裂解；(B) 混合的 CSF 中加入新鲜血液并离心（没有 RBC 的上清液在分析前被冷冻）。CSF 中氨基酸、生物胺、蝶呤和维生素的浓度通过 HPLC 结合串联质谱、电化学和荧光检测进行分析。 结果天冬氨酸、谷氨酸、牛磺酸、鸟氨酸、甘氨酸、瓜氨酸、5'-磷酸吡哆醛、5-甲基四氢叶酸、与没有 RBC 的 CSF 相比，当 RBC 被裂解时，硫胺素显示出更高的值，而精氨酸、5-羟基吲哚乙酸和高香草酸显示出更低的值。当从 CSF 中去除 RBC 时，与未加标的 CSF 样本相比，只有一些氨基酸、硫胺素和吡哆醛 5'-磷酸显示出适度更高的值。结论 CSF 靶向代谢组学分析是可行的，即使在此后 CSF 发生了大量 RBC 污染时在冷冻前通过 CSF 离心去除 RBC 消除了大部分观察到的干扰。