Otani Kosuke, Fujioka Yusei, Okada Muneyoshi, Yamawaki Hideyuki
Laboratory of Veterinary Pharmacology, School of Veterinary Medicine Kitasato University Towada Aomori Japan.
J Extracell Biol. 2025 Apr 25;4(4):e70047. doi: 10.1002/jex2.70047. eCollection 2025 Apr.
Various molecules in plasma extracellular vesicles (EVs) are expected to be applied to minimally invasive diagnosis; however, the high concentration of lipoproteins in plasma, which are similar in size, density and content to EVs, hampers analysis on plasma EVs. To overcome this, we explored an effective isolation method for plasma EVs that excludes lipoproteins by applying precipitation methods that are conventionally used to separate lipoproteins. Human plasma was mixed with heparin and MnCl, phosphotungstic acid and MgCl, or polyethylene glycol (PEG), and the expression level of CD9, Apo B and Apo A-I in both the supernatant and pellet was measured by enzyme-linked immunosorbent assay. Morphology was observed by transmission electron microscopy to assess EV yield and lipoprotein contamination. The combination of heparin and MnCl, or phosphotungstic acid and MgCl, could not separate plasma EVs and lipoproteins. PEG precipitated EVs and lipoproteins differently, and EVs were specifically precipitated by PEG (3%) to some extent. In comparison with differential ultracentrifugation (UC), size-exclusion chromatography, density gradient centrifugation and precipitation with PEG (8%) followed by UC, PEG (3%) was not inferior in efficiency but was superior in terms of time and cost. The precipitation method using PEG (3%) may contribute to the application of plasma EVs in disease diagnosis.
血浆细胞外囊泡(EVs)中的各种分子有望应用于微创诊断;然而,血浆中脂蛋白的高浓度对血浆EVs的分析造成了阻碍,因为脂蛋白在大小、密度和成分上与EVs相似。为了克服这一问题,我们探索了一种有效的血浆EVs分离方法,即通过应用传统上用于分离脂蛋白的沉淀方法来排除脂蛋白。将人血浆与肝素和氯化锰、磷钨酸和氯化镁或聚乙二醇(PEG)混合,通过酶联免疫吸附测定法测量上清液和沉淀物中CD9、载脂蛋白B和载脂蛋白A-I的表达水平。通过透射电子显微镜观察形态,以评估EVs产量和脂蛋白污染情况。肝素和氯化锰或磷钨酸和氯化镁的组合无法分离血浆EVs和脂蛋白。PEG对EVs和脂蛋白的沉淀方式不同,并且PEG(3%)在一定程度上特异性沉淀了EVs。与差速超速离心(UC)、尺寸排阻色谱、密度梯度离心以及PEG(8%)沉淀后再进行UC相比,PEG(3%)在效率上并不逊色,在时间和成本方面更具优势。使用PEG(3%)的沉淀方法可能有助于血浆EVs在疾病诊断中的应用。