Open Access Research article

Changes in gut bacterial populations and their translocation into liver and ascites in alcoholic liver cirrhotics

Sari Tuomisto13*, Tanja Pessi13, Pekka Collin2, Risto Vuento3, Janne Aittoniemi3 and Pekka J Karhunen13

Author Affiliations

1 Department of Forensic Medicine, University of Tampere, School of Medicine, Medisiinarinkatu 3, 33014 Tampere, Finland

2 Department of Gastroenterology and Alimentary Tract Surgery, Tampere University Hospital, Tampere, Finland

3 Fimlab Laboratories, Pirkanmaa Hospital District, Biokatu 4, 33520 Tampere, Finland

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BMC Gastroenterology 2014, 14:40  doi:10.1186/1471-230X-14-40

Published: 24 February 2014

Abstract

Background

The liver is the first line of defence against continuously occurring influx of microbial-derived products and bacteria from the gut. Intestinal bacteria have been implicated in the pathogenesis of alcoholic liver cirrhosis. Escape of intestinal bacteria into the ascites is involved in the pathogenesis of spontaneous bacterial peritonitis, which is a common complication of liver cirrhosis. The association between faecal bacterial populations and alcoholic liver cirrhosis has not been resolved.

Methods

Relative ratios of major commensal bacterial communities (Bacteroides spp., Bifidobacterium spp., Clostridium leptum group, Enterobactericaea and Lactobacillus spp.) were determined in faecal samples from post mortem examinations performed on 42 males, including cirrhotic alcoholics (n = 13), non-cirrhotic alcoholics (n = 15), non-alcoholic controls (n = 14) and in 7 healthy male volunteers using real-time quantitative PCR (RT-qPCR). Translocation of bacteria into liver in the autopsy cases and into the ascites of 12 volunteers with liver cirrhosis was also studied with RT-qPCR. CD14 immunostaining was performed for the autopsy liver samples.

Results

Relative ratios of faecal bacteria in autopsy controls were comparable to those of healthy volunteers. Cirrhotics had in median 27 times more bacterial DNA of Enterobactericaea in faeces compared to the healthy volunteers (p = 0.011). Enterobactericaea were also the most common bacteria translocated into cirrhotic liver, although there were no statistically significant differences between the study groups. Of the ascites samples from the volunteers with liver cirrhosis, 50% contained bacterial DNA from Enterobactericaea, Clostridium leptum group or Lactobacillus spp.. The total bacterial DNA in autopsy liver was associated with the percentage of CD14 expression (p = 0.045). CD14 expression percentage in cirrhotics was significantly higher than in the autopsy controls (p = 0.004).

Conclusions

Our results suggest that translocation of intestinal bacteria into liver may be involved as a one factor in the pathogenesis of alcoholic liver cirrhosis.

Keywords:
Alcoholic liver cirrhosis; Gut microbiota; RT-qPCR; Bacterial translocation; Microbiology; CD14