Core Metabolomics and Lipidomics Laboratory, Wellcome Trust-MRC Institute of Metabolic Science, University of Cambridge, Box 289, Cambridge Biomedical Campus, Hills Road, Cambridge CB2 0QQ, UK.
Mol Omics. 2020 Dec 1;16(6):563-572. doi: 10.1039/d0mo00102c. Epub 2020 Sep 18.
Dried blood spots (DBS) and dried milk spots (DMS) represent convenient matrices for collecting and storing human samples. However, the use of these sample types for researching lipid metabolism remains relatively poorly explored, and especially unclear is the efficiency of lipid extraction in the context of high throughput, untargeted lipidomics. A visual inspection of punched DBSs after standard extraction suggests that the samples remain largely intact. DMSs comprise a dense aggregate of milk fat globules on one side of the card, suggesting that part of the lipid fraction may be physically inaccessible. This led us to the hypothesis that decoagulating may facilitate lipid extraction from both DBSs and DMSs. We tested this hypothesis using a mixture of strong chaeotropes (guanidine and thiourea) in both DBS and DMS in the context of high throughput lipidomics (96/384w plate). Extraction of lipids from DMSs was tested with established extractions and one novel solvent mixture in a high throughput format. We found that exposure of DBSs to chaeotropes facilitated collection of the lipid fraction but was ineffective for DMSs. The lipid fraction of DMSs was best isolated without water, using a mixture of xylene/methanol/isopropanol (1 : 2 : 4). We conclude that decoagulation is essential for efficient extraction of lipids from DBSs and that a non-aqueous procedure using a spectrum of solvents is the best procedure for extracting lipids from DMSs. These methods represent convenient steps that are compatible with the sample structure and type, and with high throughput lipidomics.
干血斑 (DBS) 和干奶斑 (DMS) 是方便收集和储存人体样本的基质。然而，这些样本类型在研究脂质代谢方面的应用相对较少，特别是在高通量、非靶向脂质组学中，脂质提取的效率还不清楚。标准提取后对打孔 DBS 进行目视检查表明，样本基本保持完整。DMS 卡片一侧包含密集的乳脂球聚集物，表明部分脂质部分可能在物理上无法触及。这使我们假设，去凝聚可能有助于从 DBS 和 DMS 中提取脂质。我们使用混合强 chaotropes（胍和硫脲）在高通量脂质组学（96/384w 板）中对 DBS 和 DMS 进行了测试。在高通量格式中，用已建立的提取方法和一种新型溶剂混合物测试了从 DMS 中提取脂质。我们发现，将 DBS 暴露于 chaotropes 有助于收集脂质部分，但对 DMS 无效。DMS 的脂质部分最好在无水条件下，使用二甲苯/甲醇/异丙醇（1：2：4）混合物分离。我们得出结论，去凝聚对于从 DBS 中高效提取脂质至关重要，并且使用一系列溶剂的非水程序是从 DMS 中提取脂质的最佳程序。这些方法代表了与样本结构和类型兼容的方便步骤，并且与高通量脂质组学兼容。
