Goggs Robert
Department of Clinical Sciences, Cornell University College of Veterinary Medicine, Ithaca, New York, USA.
Vet Rec Open. 2019 Oct 1;6(1):e000357. doi: 10.1136/vetreco-2019-000357. eCollection 2019.
Cell-free DNA (cfDNA) and nucleosomes are two biomarkers of cell death and neutrophil extracellular trap formation that are increased in dogs with sepsis, immune-mediated haemolytic anaemia, cancer and following trauma and have diagnostic and prognostic values. cfDNA and nucleosomes are typically measured in plasma samples using DNA-specific fluorophores and ELISA assays, respectively, but their concentrations may be affected by pre-analytical variables such as sample type. The present study aimed to investigate the influence of sample type on the plasma cfDNA and nucleosome concentrations of a heterogeneous group of dogs presenting to an emergency room. Triplicate samples were collected into K-ethylenediamine tetraacetic acid, 3.2% citrate and a specialised DNA stabilisation tube (Streck BCT), processed rapidly and frozen for batch analysis. Biomarker concentrations were compared between sample types by calculation of Spearman's correlation coefficients, and with Deming regression, Bland-Altman plots and the Friedman test. Overall, biomarker concentrations were highly correlated between the three sample types. The most concordant results were obtained using citrate samples and the DNA stabilisation tube. Matched cfDNA concentrations between the different sample types were significantly different but there was no significant difference between the nucleosome concentrations in any of the sample types. The present study suggests that cfDNA and nucleosomes can be successfully measured in various sample types, but distinct sample types do not produce interchangeable results. This argues for use of a consistent sample type within studies and suggests standardisation may be useful for the field.
游离DNA（cfDNA）和核小体是细胞死亡和中性粒细胞胞外诱捕网形成的两种生物标志物，在患有败血症、免疫介导的溶血性贫血、癌症的犬以及创伤后的犬中含量会升高，具有诊断和预后价值。通常分别使用DNA特异性荧光团和酶联免疫吸附测定（ELISA）法在血浆样本中测量cfDNA和核小体，但它们的浓度可能会受到诸如样本类型等分析前变量的影响。本研究旨在调查样本类型对送至急诊室的一组异质犬的血浆cfDNA和核小体浓度的影响。将一式三份的样本收集到含有乙二胺四乙酸钾、3.2%柠檬酸盐的试管以及专用DNA稳定管（Streck BCT）中，快速处理后冷冻以便进行批量分析。通过计算斯皮尔曼相关系数、采用戴明回归、布兰德-奥特曼图和弗里德曼检验来比较不同样本类型之间的生物标志物浓度。总体而言，三种样本类型之间的生物标志物浓度高度相关。使用柠檬酸盐样本和DNA稳定管获得的结果最为一致。不同样本类型之间匹配的cfDNA浓度存在显著差异，但任何样本类型中的核小体浓度之间均无显著差异。本研究表明，可以在各种样本类型中成功测量cfDNA和核小体，但不同的样本类型不会产生可互换的结果。这支持在研究中使用一致的样本类型，并表明标准化可能对该领域有用。
