West Coast Metabolomics Center, Genome Center, University of California Davis, Davis, CA, USA.
Department of Nutrition, University of California Davis, Davis, CA, USA.
Metabolomics. 2018 Nov 15;14(11):151. doi: 10.1007/s11306-018-1450-9.
Population-based biorepositories are important resources, but sample handling can affect data quality.
Identify metabolites of value for clinical investigations despite extended postcollection freezing delays, using protocols representing a California mid-term pregnancy biobank.
Blood collected from non-pregnant healthy female volunteers (n = 20) underwent three handling protocols after 30 min clotting at room temperature: (1) ideal-samples frozen (- 80 °C) within 2 h of collection; (2) delayed freezing-samples held at room temperature for 3 days, then 4 °C for 9 days, the median times for biobank samples, and then frozen; (3) delayed freezing with freeze-thaw-the delayed freezing protocol with a freeze-thaw cycle simulating retrieved sample sub-aliquoting. Mass spectrometry-based untargeted metabolomic analyses of primary metabolism and complex lipids and targeted profiling of oxylipins, endocannabinoids, ceramides/sphingoid-bases, and bile acids were performed. Metabolite concentrations and intraclass correlation coefficients (ICC) were compared, with the ideal protocol as the reference.
Sixty-two percent of 428 identified compounds had good to excellent ICCs, a metric of concordance between measurements of samples handled with the different protocols. Sphingomyelins, phosphatidylcholines, cholesteryl esters, triacylglycerols, bile acids and fatty acid diols were the least affected by non-ideal handling, while sugars, organic acids, amino acids, monoacylglycerols, lysophospholipids, N-acylethanolamides, polyunsaturated fatty acids, and numerous oxylipins were altered by delayed freezing. Freeze-thaw effects were assay-specific with lipids being most stable.
Despite extended post-collection freezing delays characteristic of some biobanks of opportunistically collected clinical samples, numerous metabolomic compounds had both stable levels and good concordance.
基于人群的生物库是重要资源，但样本处理会影响数据质量。
使用代表加利福尼亚中期妊娠生物库的方案，确定尽管有延长的采集后冷冻延迟，但仍对临床研究有价值的代谢物。
从非妊娠健康女性志愿者（n=20）采集的血液在室温下凝结 30 分钟后，根据以下三种处理方案进行处理：（1）理想样本 - 在采集后 2 小时内冷冻（-80°C）；（2）延迟冷冻 - 在室温下放置 3 天，然后在 4°C 下放置 9 天，这是生物库样本的中位数时间，然后冷冻；（3）延迟冷冻加冻融 - 模拟检索的样本分样的延迟冷冻方案加上冻融循环。对初级代谢物和复杂脂质进行基于质谱的非靶向代谢组学分析，并对氧化脂类、内源性大麻素、神经酰胺/鞘氨醇碱基和胆汁酸进行靶向分析。比较了不同处理方案下的代谢物浓度和组内相关系数（ICC），以理想方案为参考。
428 种鉴定化合物中有 62%的化合物具有良好到极好的 ICC，这是衡量不同处理方案下样品测量值一致性的指标。鞘磷脂、磷脂酰胆碱、胆固醇酯、三酰甘油、胆汁酸和脂肪酸二醇受非理想处理影响最小，而糖、有机酸、氨基酸、单酰基甘油、溶血磷脂、N-酰基乙醇酰胺、多不饱和脂肪酸和许多氧化脂类则受到冷冻延迟的影响。冻融效应具有特定的检测方法，脂质最为稳定。
尽管一些机会性收集临床样本的生物库具有延长的采集后冷冻延迟特征，但仍有许多代谢组学化合物具有稳定的水平和良好的一致性。
Zotero 插件