Institute of Forensic Medicine, Forensic Toxicology and Chemistry, University of Bern, Bern, Switzerland.
Department of Chemistry, Biochemistry and Pharmaceutical Sciences, University of Bern, Bern, Switzerland.
Eur J Mass Spectrom (Chichester). 2023 Oct;29(5-6):338-347. doi: 10.1177/14690667231200143. Epub 2023 Sep 14.
Alcohol biomarkers are able to reflect the degree of recent or long-term alcohol consumption, covering different windows of detection. Phosphatidylethanols (PEths) are an emerging group of direct alcohol biomarkers that are widely applied in clinical and forensic applications. Their quantification can provide insight into an individual's drinking behaviour. Here, we present a new sub-class of yet unknown PEth species, LysoPEths, which are structurally related to PEth, but miss one fatty acyl chain. LysoPEths can be either a degradation product of PEth or a product of transesterification of lyso-phosphatidylcholine (LysoPC) with ethanol. To set up an analytical method, LysoPEth 16:0 was synthesised from PC 16:0/18:1 and characterised by LC-MS/MS, using an enzymatic method: phospholipase D (PLD), followed by phospholipase A (PLA). Then, an LC-MS/MS method in MRM mode for LysoPEth 16:0 with additional LysoPEth species (LysoPEth 18:1, LysoPEth 18:2, and LysoPEth 20:4) and PEth 16:0/20:4 was developed. By incubation of freshly sampled venous blood of a teetotaller with ethanol at different concentrations, the formation of LysoPEth in parallel to PEth was investigated. With increasing ethanol concentrations, LysoPEth 16:0 was formed besides the known PEth species (PEth 16:0/18:1, PEth 16:0/18:2) for up to 72 h with LysoPEth concentrations being about three times lower than PEth concentrations. Storage of ethanol-free PEth-positive blood of an alcohol consumer at 37 °C showed that LysoPEth 16:0 concentrations increased, while PEth 16:0/18:1 concentrations decreased in the first 24 h for frozen/thawed blood, however not for freshly collected blood. Furthermore, LysoPEth 16:0 was detected in venous as well as lyophilised blood from clinical and forensic case work alongside with PEth 16:0/18:1, 16:0/18:2, and other PEth and LysoPEth species (PEth 16:0/20:4, LysoPEth 18:1, LysoPEth 18:2, and LysoPEth 20:4). LysoPEth 16:0 concentrations were found to be in linear correlation with PEth 16:0/18:1 (r= 0.75).
酒精生物标志物能够反映近期或长期的酒精摄入量，涵盖了不同的检测窗口。磷酸乙醇胺（PEth）是一组新兴的直接酒精生物标志物，广泛应用于临床和法医领域。它们的定量可以深入了解个体的饮酒行为。在这里，我们介绍了一种新的未知 PEth 物质亚类，即溶血磷脂酰乙醇胺（LysoPEth），它与 PEth 结构相关，但缺少一个脂肪酸链。LysoPEth 可以是 PEth 的降解产物，也可以是溶血磷脂酰胆碱（LysoPC）与乙醇发生转酯化反应的产物。为了建立一种分析方法，我们从 PC 16:0/18:1 合成了 LysoPEth 16:0，并通过 LC-MS/MS 进行了表征，采用酶法：磷脂酶 D（PLD），然后是磷脂酶 A（PLA）。然后，我们开发了一种 LC-MS/MS 方法，以 MRM 模式检测 LysoPEth 16:0 及其它 LysoPEth 物质（LysoPEth 18:1、LysoPEth 18:2 和 LysoPEth 20:4）和 PEth 16:0/20:4。通过在不同浓度的乙醇中孵育新采集的静脉血，我们研究了 LysoPEth 与 PEth 同时形成的情况。随着乙醇浓度的增加，除了已知的 PEth 物质（PEth 16:0/18:1、PEth 16:0/18:2）外，还形成了 LysoPEth 16:0，其浓度高达 72 小时，而 LysoPEth 浓度约为 PEth 浓度的三分之一。将一位酒精消费者的不含乙醇的 PEth 阳性血液在 37°C 下储存，结果表明 LysoPEth 16:0 浓度增加，而冷冻/解冻血液中的 PEth 16:0/18:1 浓度在最初 24 小时内下降，但新鲜采集的血液则没有。此外，我们在临床和法医案例工作中，从静脉血和冻干血中同时检测到了 LysoPEth 16:0 和 PEth 16:0/18:1、16:0/18:2 以及其它的 PEth 和 LysoPEth 物质（PEth 16:0/20:4、LysoPEth 18:1、LysoPEth 18:2 和 LysoPEth 20:4）。LysoPEth 16:0 浓度与 PEth 16:0/18:1 呈线性相关（r=0.75）。
