Mounting evidences suggest a rising trend of non-alcoholic fatty liver disease (NAFLD) which has also considered as one of the leading liver diseases worldwide. It is characterized by hepatic steatosis and may advance to an inflammatory condition termed non-alcoholic steatohepatitis (NASH), liver cirrhosis, and hepatocellular carcinoma. Data from the studies conducted in the last years revealed that NAFLD pathophysiology is complex and includes diverse immunological and metabolic pathways. 

It has been observed that a correlation exists between intestinal signals, which are derived from the gut microbiota, and the development of obesity and its metabolic consequences such as NAFLD. Pre-clinical studies have demonstrated that germ-free experimental animals can be prevented against obesity and hepatic steatosis. Various human trials conducted from the past years have also shown that NAFLD contains a disease-specific gut microbiome signature. Few controlled studies have revealed that certain bacteria with pro-inflammatory features such as Proteobacteria or Escherichia coli are mainly present in patients with NAFLD whereas protective bacteria such as Faecalibacterium prausnitzii are reduced in these patients. Moreover, numerous bacterial metabolites and microbiota-generated secondary bile acids are implicated in NAFLD-associated metabolic dysfunction. 

These observations of bacterial metabolites open a window for new research in fatty liver diseases, as they can help regulating the evolution of hepatic steatosis and insulin signalling. However, additional research are warranted that can utilize the interference at the level of the gut microbiome for therapeutic modalities for the management of these diseases.  Therefore, deciphering disease processes can aid in the development of innovative treatment modalities desperately needed for NAFLD.

Source: Grabherr F, Grander C, Effenberger M, Adolph TE, Tilg H. Gut Dysfunction and Non-alcoholic Fatty Liver Disease. Front Endocrinol (Lausanne). 2019 Sep 6;10:611.