Understanding the Effects of Gut Microbiota Dysbiosis on Nonalcoholic Fatty Liver Disease and the Possible Probiotics Role: Recent Updates

Abstract

Nonalcoholic fatty liver disease (NAFLD) is leading chronic liver syndrome worldwide. Gut microbiota dysbiosis significantly contributes to the pathogenesis and severity of NAFLD. However, its role is complex and even unclear. Treatment of NAFLD through chemotherapeutic agents have been questioned because of their side effects on health. In this review, we highlighted and discussed the current understanding on the importance of gut microbiota, its dysbiosis and its effects on the gut-liver axis and gut mucosa. Further, we discussed key mechanisms involved in gut dysbiosis to provide an outline of its role in progression to NAFLD and liver cirrhosis. In addition, we also explored the potential role of probiotics as a treatment approach for the prevention and treatment of NAFLD. Based on the latest findings, it is evident that microbiota targeted interventions mostly the use of probiotics have shown promising effects and can possibly alleviate the gut microbiota dysbiosis, regulate the metabolic pathways which in turn inhibit the progression of NAFLD through the gut-liver axis. However, very limited studies in humans are available on this issue and suggest further research work to identify a specific core microbiome association with NAFLD and to discover its mechanism of pathogenesis, which will help to enhance the therapeutic potential of probiotics to NAFLD.

Keywords: Nonalcoholic fatty liver disease; dysbiosis; gut microbiota; nonalcoholic steatohepatitis; probiotics; small intestinal bacterial overgrowth..

Figure 1

Illustration of how small intestinal bacterial overgrowth impacts the gut microbiota dysbiosis and progression of NAFLD.

Figure 2

Proposed mechanisms showing the role of high-fat and sugar diets in the progression of gut microbiota dysbiosis and development of the nonalcoholic fatty liver disease.

Figure 3

Probiotics mechanisms of action in alleviating the host gut microbiota homeostasis. Probiotics could alleviate the gut disorders (NAFLD), by modulating the gut microbiota, prevent the translocation of bacterial toxins, reduce the gut permeability and regulate the immune response.