脑脊液（CSF）是一系列神经病症的诊断生物标志物来源。细胞外DNA（cfDNA）可在CSF中检测到，神经退行性疾病研究中报告了细胞外线粒体DNA浓度的差异，包括阿尔茨海默病（AD）。然而，对于CSF中的cfDNA，预分析步骤的影响尚未研究，并且没有标准化的方法用于总cfDNA（核基因组或线粒体源基因目标的副本数）的定量。本研究评估了四种提取方法的适用性：QIAamp循环核酸（Qiagen）、Quick-cfDNA血清和血浆（Zymo）、NucleoSnap® DNA血浆（Macherey-Nagel）和Plasma / Serume 细胞DNA纯化Mini（Norgen）套件，用于从对照组和AD痴呆症患者的CSF中提取cfDNA，利用峰内控制提取效率与片段大小。其中一种最佳提取方法应用于比较对照组、AD痴呆和原发性和继发性脑肿瘤患者的CSF中cfDNA的浓度。基于内标回收的提取效率在所有三组中都相似，而内源性线粒体和核基因组来源的cfDNA在癌症患者的CSF中显著高于对照组和AD组，后者通常含有＜100基因组拷贝/ mL。本研究表明，测量低浓度核基因组和线粒体基因靶标在CSF中是可行的，提取产量的标准化可以帮助控制影响生物标志物测量的分析前变异性。版权所有©2022年作者。由Elsevier B.V.出版。保留所有权利。

Cerebrospinal fluid (CSF) is a source of diagnostic biomarkers for a range of neurological conditions. Cell-free DNA (cfDNA) is detected in CSF and differences in the concentration of cell-free mitochondrial DNA have been reported in studies of neurodegenerative disorders including Alzheimer's disease (AD). However, the influence of pre-analytical steps has not been investigated for cfDNA in CSF and there is no standardised approach for quantification of total cfDNA (copies of nuclear genome or mitochondria-derived gene targets). In this study, the suitability of four extraction methods was evaluated: QIAamp Circulating Nucleic Acid (Qiagen), Quick-cfDNA Serum & Plasma (Zymo), NucleoSnap® DNA Plasma (Macherey-Nagel) and Plasma/Serum Circulating DNA Purification Mini (Norgen) kits, for cfDNA extraction from CSF of controls and AD dementia patients, utilising a spike-in control for extraction efficiency and fragment size. One of the optimal extraction methods was applied to a comparison of cfDNA concentrations in CSF from control subjects, AD dementia and primary and secondary brain tumour patients. Extraction efficiency based on spike-in recovery was similar in all three groups whilst both endogenous mitochondrial and nucleus-derived cfDNA was significantly higher in CSF from cancer patients compared to control and AD groups, which typically contained < 100 genome copies/mL. This study shows that it is feasible to measure low concentration nuclear and mitochondrial gene targets in CSF and that normalisation of extraction yield can help control pre-analytical variability influencing biomarker measurements.Copyright © 2022 The Authors. Published by Elsevier B.V. All rights reserved.