The gut microbiota and the liver: implications for clinical practice

Abstract

While a central role for the microbiota in the precipitation of infectious and non-infectious complications of liver disease has been long established, evidence for a more fundamental role in the etiology of several liver diseases continues to accumulate. However, though progress is rapidly occurring in this area, the definitive delineation of the precise relevance of changes in the microbiota to various forms and stages of liver disease is still far from complete. While high quality clinical evidence supports the use of antibiotic therapy, in the management of hepatic encephalopathy, spontaneous bacterial peritonitis and other infectious complications, how these interventions impact on the microbiota and microbiota–host interactions has not been clearly defined. Although probiotics and even, perhaps, fecal transplantation hold promise in the management of liver disease, and the potential impact of probiotics is supported by a considerable amount of laboratory data, high-quality clinical evidence is scanty.

Keywords::

• alcoholic liver disease
• antibiotics
• hepatic encephalopathy
• liver disease
• microbiota
• non-alcoholic liver disease
• prebiotics
• probiotics
• spontaneous bacterial peritonitis

Financial & competing interests disclosure

The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.

No writing assistance was utilized in the production of this manuscript.

Key issues

• • The concept of the gut-liver axis has now been extended to the microbiota–gut–liver axis.

• • Fundamental roles for the microbiota in immunity and metabolism highly relevant to liver function and disease.

• • Extensive animal and accumulating human data to indicate a pivotal role of the microbiota in important complications of chronic liver disease.

• • Emerging literature supporting a possible role of the microbiota in the basic pathogenesis of certain liver diseases, such as non-alcoholic fatty liver disease.

• • With the exception of the role of antibiotics in hepatic encephalopathy, spontaneous bacterial peritonitis and other infectious complications little data on the therapeutic benefits of microbiota manipulation in liver disease.

• • Experimental and very limited human data suggests that microbiota modification may ameliorate liver abnormalities linked to metabolic syndrome.