Insights into the Impact of Microbiota in the Treatment of NAFLD/NASH and Its Potential as a Biomarker for Prognosis and Diagnosis

Abstract

Non-alcoholic fatty liver disease (NAFLD) is an increasing cause of chronic liver illness associated with obesity and metabolic disorders, such as hypertension, dyslipidemia, or type 2 diabetes mellitus. A more severe type of NAFLD, non-alcoholic steatohepatitis (NASH), is considered an ongoing global health threat and dramatically increases the risks of cirrhosis, liver failure, and hepatocellular carcinoma. Several reports have demonstrated that liver steatosis is associated with the elevation of certain clinical and biochemical markers but with low predictive potential. In addition, current imaging methods are inaccurate and inadequate for quantification of liver steatosis and do not distinguish clearly between the microvesicular and the macrovesicular types. On the other hand, an unhealthy status usually presents an altered gut microbiota, associated with the loss of its functions. Indeed, NAFLD pathophysiology has been linked to lower microbial diversity and a weakened intestinal barrier, exposing the host to bacterial components and stimulating pathways of immune defense and inflammation via toll-like receptor signaling. Moreover, this activation of inflammation in hepatocytes induces progression from simple steatosis to NASH. In the present review, we aim to: (a) summarize studies on both human and animals addressed to determine the impact of alterations in gut microbiota in NASH; (b) evaluate the potential role of such alterations as biomarkers for prognosis and diagnosis of this disorder; and (c) discuss the involvement of microbiota in the current treatment for NAFLD/NASH (i.e., bariatric surgery, physical exercise and lifestyle, diet, probiotics and prebiotics, and fecal microbiota transplantation).

Associations Between GGT/HDL and MAFLD: A Cross-Sectional Study

“…56,57 Accumulating evidence indicated that gut microbial dysbiosis was associated with the pathogenesis of MAFLD, 58 which was related to low-grade inflammation. 59 Therefore, GGT/HDL was closely correlated with MAFLD.…”

Impact of Dietary Patterns on H. pylori Infection and the Modulation of Microbiota to Counteract Its Effect. A Narrative Review

“…Diet has a considerable effect on the composition of gastrointestinal microbiota and an unhealthy diet, among other factors, alters its composition and induces gastric microbial dysbiosis [ 52 ]. The gut microbiome is the genetic material of all the microbes that live on and inside the human body [ 53 , 54 , 55 ]. H. pylori colonization results in the alteration of gastric microbiota and a reduction in bacterial diversity [ 56 , 57 ], thus modifying the host’s gut microbiome [ 58 ].…”

Biodiversity of Gut Microbiota: Impact of Various Host and Environmental Factors

“…They have also been linked to the prevention and treatment of cardiovascular diseases like hypertension [ 8 , 9 ], along with enhanced predisposition towards various viral and bacterial infections. In various other studies, these “healthy” microbiota have been associated with the treatment of various metabolic diseases like obesity [ 10 , 11 ], diabetes, and nonalcoholic fatty liver disease (NAFLD) [ 12 ]. The emerging role of these microbiota has also been reported as a mitigation strategy against various respiratory viral infections [ 13 ] including COVID-19 [ 14 , 15 ].…”