Departamento de Medicina y Especialidades Médicas, Universidad de Alcalá, Alcalá de Henares, Spain.
Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd), Instituto de Salud Carlos III, Madrid, Spain.
Hepatology. 2019 Sep;70(3):925-938. doi: 10.1002/hep.30349. Epub 2019 Mar 5.
In cirrhosis, intestinal dysbiosis, intestinal barrier impairment, and systemic immune system abnormalities lead to gut bacterial translocation (GBT) and bacterial infection. However, intestinal immune system dysfunction and its contribution to barrier damage are poorly understood. This study correlates immune system dysregulation in the intestines of rats at different stages of CCl -induced cirrhosis with barrier function and pathogenic microbiota. The following variables were addressed in the small intestine: intraepithelial lymphocyte (IEL) and lamina propria lymphocyte (LPL) activation status and cytokine production (flow cytometry), cytokine mRNA and protein expression (quantitative real-time PCR and immunofluorescence), microbiota composition of ileum content (16S recombinant DNA massive sequencing), permeability (fecal albumin loss), and epithelial junctions (immunohistochemistry and immunofluorescence). The intestinal mucosa in rats with cirrhosis showed a proinflammatory pattern of immune dysregulation in IELs and LPLs, which featured the expansion of activated lymphocytes, switch to a T helper 1 (Th1) regulatory pattern, and Th17 reduction. In rats with cirrhosis with ascites, this state was associated with epithelial junction protein disruption, fecal albumin loss, and GBT. Direct correlations (P < 0.01) were observed between elevated interferon gamma (IFNγ)-expressing T cytotoxic LPLs and fecal albumin and between inflammatory taxa abundance and IFNγ-producing immune cells in the ileum. Bowel decontamination led to redistributed microbiota composition, reduced proinflammatory activation of mucosal immune cells, normalized fecal albumin levels, and diminished GBT; but there were no modifications in Th17 depletion. Conclusion: The intestinal mucosa of rats with cirrhosis acquires a proinflammatory profile of immune dysregulation that parallels the severity of cirrhosis; this impaired intestinal immune response is driven by gut dysbiosis and leads to disrupted barrier function, promoting GBT.
在肝硬化中，肠道菌群失调、肠道屏障损伤和全身免疫系统异常导致肠道细菌易位（GBT）和细菌感染。然而，肠道免疫系统功能障碍及其对屏障损伤的贡献仍知之甚少。本研究将 CCl4 诱导的肝硬化大鼠不同阶段肠道免疫系统失调与屏障功能和致病微生物群相关联。在小肠中研究了以下变量：上皮内淋巴细胞（IEL）和固有层淋巴细胞（LPL）的激活状态和细胞因子产生（流式细胞术）、细胞因子 mRNA 和蛋白表达（定量实时 PCR 和免疫荧光）、回肠内容物的微生物群组成（16S 重组 DNA 大规模测序）、通透性（粪便白蛋白损失）和上皮连接（免疫组织化学和免疫荧光）。肝硬化大鼠的肠道黏膜显示出 IEL 和 LPL 中炎症性免疫失调的模式，其特征是激活淋巴细胞的扩张、向 T 辅助 1（Th1）调节模式的转变以及 Th17 的减少。在伴有腹水的肝硬化大鼠中，这种状态与上皮连接蛋白破坏、粪便白蛋白损失和 GBT 相关。在肝硬化大鼠中，IFNγ 表达的 T 细胞毒性 LPL 与粪便白蛋白之间以及回肠中炎性分类群丰度与 IFNγ 产生免疫细胞之间存在直接相关性（P<0.01）。肠道去污导致微生物群组成重新分布，减少了黏膜免疫细胞的促炎激活，使粪便白蛋白水平正常化，并减少了 GBT；但 Th17 耗竭没有改变。结论：肝硬化大鼠的肠道黏膜获得了炎症性免疫失调的特征，与肝硬化的严重程度平行；这种受损的肠道免疫反应是由肠道菌群失调驱动的，导致屏障功能障碍，促进 GBT。
