Background

Extracellular vesicles (EVs) have recently attracted attention as novel diagnostic biomarkers and therapeutic tools. Several reports have correlated blood EVs with liver diseases. However, blood EVs do not reflect the liver state as it contains other systemically circulating EVs. Therefore, we focused on bile EVs, which are secreted directly from the liver, for the identification of potential biomarkers of liver failure.

Methods

Bile samples were collected from liver transplant recipients (n = 21) diagnosed with end-stage liver disease (ESLD) and donors (normal liver, NL; n = 18) during transplantation. Bile EVs were extracted using ultracentrifugation.

Results

Nanoparticle tracking analysis showed that bile EV concentration was significantly higher in recipients than in donors. Among recipients, bile EV concentration was remarkably higher in those with hepatocellular carcinoma. Next-generation sequencing revealed 461 and 465 types of microRNAs (miRNAs) in donor and recipient bile EVs, respectively, with no significant difference in diversity between the groups. Among 43 high-expression miRNAs, the expression of 86.0% of the miRNAs was higher in the bile EVs of recipients than in those of donors. Quantitative PCR validation showed that the levels of miR-17, miR-92a, miR-25, miR-423, and miR-451a significantly increased in bile EVs of recipients. Levels of miR-17 were remarkably higher in recipients with alcoholic ESLD.

Conclusions

Secretion of EVs into the bile and their miRNA content increase in the ESLD state. Additionally, miRNA levels in bile EVs are not correlated with those in serum EVs. Bile EVs could be promising novel biomarkers for liver diseases.

中文翻译：

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来自终末期肝病患者的胆汁细胞外囊泡显示出改变的 microRNA 含量

背景

细胞外囊泡（EVs）最近作为新型诊断生物标志物和治疗工具引起了人们的关注。一些报告将血液 EV 与肝脏疾病相关联。然而，血液 EV 不能反映肝脏状态，因为它包含其他全身循环的 EV。因此，我们专注于直接从肝脏分泌的胆汁 EV，用于鉴定肝衰竭的潜在生物标志物。

方法

胆汁样本收集自肝移植受者（n  = 21）和移植期间诊断为终末期肝病（ESLD）的肝移植受者（n  = 18）和供者（正常肝脏，NL；n = 18）。使用超速离心法提取胆汁 EV。

结果

纳米粒子追踪分析表明，受体的胆汁 EV 浓度明显高于供体。在受者中，肝细胞癌患者的胆汁 EV 浓度显着更高。下一代测序揭示了供体和受体胆汁 EV 中分别有 461 和 465 种 microRNA（miRNA），两组之间的多样性没有显着差异。在 43 种高表达 miRNA 中，86.0% 的 miRNA 在受体胆汁 EV 中的表达高于供体。定量 PCR 验证表明，受者胆汁 EV 中 miR-17、miR-92a、miR-25、miR-423 和 miR-451a 的水平显着增加。患有酒精性 ESLD 的受者的 miR-17 水平显着更高。

结论

在 ESLD 状态下，EV 分泌到胆汁中，其 miRNA 含量增加。此外，胆汁 EV 中的 miRNA 水平与血清​​ EV 中的 miRNA 水平无关。胆汁 EVs 可能是肝脏疾病的有前途的新型生物标志物。