Leticia Muñoz1,2, María-José Borrero1,2, María Úbeda1,2, Elisa Conde3, Rosa Del Campo4, Macarena Rodríguez-Serrano3, Margaret Lario1,2, Ana-María Sánchez-Díaz4, Oscar Pastor5, David Díaz1,2,6, Laura García-Bermejo3, Jorge Monserrat1,2,6, Melchor Álvarez-Mon1,2,6, Agustín Albillos1,2,7. 1. Departamento de Medicina y Especialidades Médicas, Universidad de Alcalá, Alcalá de Henares, Spain. 2. Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd), Instituto de Salud Carlos III, Madrid, Spain. 3. Unidad de Biomarcadores y Dianas Terapéuticas, Hospital Universitario Ramón y Cajal, IRYCIS, Madrid, Spain. 4. Servicio de Microbiología, Hospital Universitario Ramón y Cajal, IRYCIS, Red Española de Investigación en Enfermedades Infecciosas (REIPI), Instituto de Salud Carlos III, Madrid, Spain. 5. Servicio de Bioquímica Clínica, Hospital Universitario Ramón y Cajal, IRYCIS, Madrid, Spain. 6. Servicio de Enfermedades del Sistema Inmune y Oncología, Hospital Universitario Príncipe de Asturias, Universidad de Alcalá, Alcalá de Henares, Spain. 7. Servicio de Gastroenterología y Hepatología, Hospital Universitario Ramón y Cajal, Universidad de Alcalá, IRYCIS, Madrid, Spain.
Abstract
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 CCl4 -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.
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 CCl4 -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.
Authors: Jasmohan S Bajaj; Nita H Salzman; Chathur Acharya; Richard K Sterling; Melanie B White; Edith A Gavis; Andrew Fagan; Michael Hayward; Mary L Holtz; Scott Matherly; Hannah Lee; Majdi Osman; Mohammad S Siddiqui; Michael Fuchs; Puneet Puri; Masoumeh Sikaroodi; Patrick M Gillevet Journal: Hepatology Date: 2019-06-18 Impact factor: 17.425