Gut microbiota dysbiosis in patients with biopsy-proven nonalcoholic fatty liver disease: A cross-sectional study in Taiwan

The gut microbiota plays a role in nonalcoholic fatty liver disease (NAFLD), but data about gut dysbiosis in Asians with NAFLD remains scarce. We analyzed the differences in fecal microbiota between adults with and without NAFLD. This cross-sectional study examined adults with histology-proven NAFLD (25 nonalcoholic fatty liver (NAFL) patients, 25 nonalcoholic steatohepatitis (NASH) patients, and 25 living liver donors (healthy controls)). The taxonomic composition of the gut microbiota was determined by 16S ribosomal RNA gene sequencing of stool samples. The NAFL and NASH groups showed lower total bacterial diversity and richness than the controls. NAFLD patients had higher levels of the phylum Bacteroidetes and lower levels of Firmicutes than controls. The genus Ruminococcaceae UCG-010, family Ruminococcaceae, order Clostridiales, and class Clostridia were less abundant in patients with NAFL or NASH than healthy individuals. The lipopolysaccharide biosynthesis pathway was differentially enriched in the NASH group. This study examined the largest number of Asian patients with biopsy-proven NAFL and NASH in terms of dysbiosis of the gut microbiota in NAFLD patients. NAFLD patients had higher levels of Bacteroidetes and lower levels of Firmicutes. These results are different from research from western countries and could provide different targets for therapies by region.