Microbiome Composition by Pyrosequencing in Mesenteric Lymph Nodes of Rats with CCl₄-Induced Cirrhosis

Abstract

Background: The cross talk between the gut microbiota and the immune system, which is essential to maintain homeostasis, takes place at the intestinal lymphoid tissue such as the mesenteric lymph nodes (MLNs). Here, we investigated the presence of bacterial DNA in MLNs of control and cirrhotic rats and its relationship with inflammatory responses. Methods: The MLN microbiome of cirrhotic rats with ascites, which was induced by carbon tetrachloride (CCl₄), was compared to that of control rats using quantitative real-time PCR and pyrosequencing of the 16S rRNA gene. Cytokines in blood samples were assessed by ELISA. Results: Unexpectedly, sequence analysis revealed a high microbial diversity in the MLNs of both control and cirrhotic rats with Proteobacteria as one of the most dominant phylum. CCl₄-induced liver injury was not associated with a change in bacterial load, but it was linked to a decrease in microbial diversity (p < 0.05) and alterations in the microbial community in MLNs. A high proportion of Bifidobacterium animalis was also positively correlated with elevated interleukin-10 expression (p = 0.002, false discovery rate = 0.03, r = 0.94). Conclusions: For the first time, the high microbial diversity observed in MLNs of both controls and CCl₄-induced cirrhotic rats provides evidence that bacterial translocation is more than a mere dichotomic phenomenon.

VSL#3 probiotic treatment decreases bacterial translocation in rats with carbon tetrachloride‐induced cirrhosis

“…Moreover, we did not observe statistically significant changes with VSL#3 treatment in the intestinal concentration of the bacteria responsible for bacterial translocation (enterobacteria and enterococci) evaluated by microbiological culture. We cannot rule out other effects of VSL#3 on intestinal or mesenteric lymph nodes microbiota that could have been demonstrated using a more comprehensive evaluation including molecular techniques . Finally, the beneficial effects of VSL#3 on bacterial translocation seem to be related, at least in part, to improvements in the intestinal barrier, as observed by the increase in ileal occludin concentration.…”

Implications of microbiota and bile acid in liver injury and regeneration

“…Carbon tetrachloride-induced cirrhosis was linked to a decreased microbial diversity [38]. In addition, a high proportion of Bifidobacterium animalis was also positively correlated with elevated IL-10 expression, which reinforces the hepatoprotective effects of Bifidobacterium species [38].…”

“…Carbon tetrachloride-induced cirrhosis was linked to a decreased microbial diversity [38]. In addition, a high proportion of Bifidobacterium animalis was also positively correlated with elevated IL-10 expression, which reinforces the hepatoprotective effects of Bifidobacterium species [38]. Additionally, Bifidobacterium infantis has been implicated in modulating colonic microbial diversity and reducing fecal endotoxin levels [39].…”

Methods to determine intestinal permeability and bacterial translocation during liver disease

“…We have used an E. coli antibody (Dako) to determine direct hepatic translocation of PAMPs (Chen et al, 2014b). Similarly, bacterial DNA can be amplified from tissue using common 16S ribosomal primers (unpublished results) or deep 16 rRNA sequencing (Cuenca et al, 2014). …”