The Association of Gut Microbiota with Nonalcoholic Steatohepatitis in Thais

Abstract

Objectives Nonalcoholic steatohepatitis (NASH) can progress to advanced fibrosis; the link between intestinal bacterial overgrowth and NASH has been proposed. Gut microbiota may promote inflammation and provoke disease progression. We evaluated gut microbiota pattern in NASH and its influencing factors. Methods A case-controlled study with sixteen NASH and eight control subjects was done. We performed DNA extraction from stool samples and bacterial 16S rRNA sequencing using MiSeq™. The sequences were clustered into operational taxonomic units using Quantitative Insights Into Microbial Ecology software. We calculated relative abundances, determined alpha diversity, obtained beta diversity by principal coordinate analysis, and conducted the partial least-squares regression model. Results The relative abundance of Bacteroidetes tended to be higher in NASH group. The Bacteroidetes/Firmicutes (B/F) ratio was significantly elevated in NASH patients. The pattern of gut microbiota in NASH was clearly separated from that of control subjects. Factors influencing the separation of NASH from control subjects were age, diabetes, body mass index, Bacteroidetes phylum, metformin, Actinobacteria, Verrucomicrobia, Thermotogae, and Caldithrix and Bacteroidetes/Firmicutes ratio. Conclusions Bacteroidetes phylum (Bacteroides and Prevotella genus) is abundant in NASH subjects, who exhibited an elevated B/F ratio. NASH patients showed a specific pattern of gut microbiota independent of diabetes or metformin use.

Role of Gut Dysbiosis in Liver Diseases: What Have We Learned So Far?

“…Marked differences between their results and other results may reflect variations in environmental and dietary factors, as well as age, among the patient cohorts [93]. Coming back to the fecal levels of Bacteroidetes, these studies are in quite contrast to those by Zhu et al [84] and Sobhonslidsuk et al [94], which showed enriched Bacteroidetes in NASH patients compared with healthy controls. Although the reason for this discrepancy is far from clear, marked increase in Prevotella within Bacteroidetes phylum is the common finding in the latter two studies [84,94].…”

“…Sobhonslidsuk et al [94] also noted enriched fecal Prevotella in NASH patients in Thailand. The increase in fecal Prevotella was further reported in Chinese cirrhotic patients [98].…”

“…Although the reason for this discrepancy is far from clear, marked increase in Prevotella within Bacteroidetes phylum is the common finding in the latter two studies [84,94]. Sobhonslidsuk et al [94] discussed advanced fibrosis stages in their patients compared with those in other studies may explain the increased fecal abundance of Bacteroidetes, as Boursier et al [95] reported higher fecal abundance of Bacteroidetes in NAFLD patients with significant fibrosis than those with mild fibrosis.…”

Phenotyping non‐alcoholic fatty liver disease by the gut microbiota: Ready for prime time?

“…Thirteen cross‐sectional studies analyzing the gut bacterial microbiota composition in humans with NAFLD were included. Most of these studies performed 16S rRNA gene sequencing, obtained by different sequencing technologies, namely, pyrosequencing 2,11,14,16,18,20,22 and Illumina NGS sequencing 15,17,23,24 . Two studies used whole genome shotgun sequencing 19 and quantitative polymerase chain reaction, 21 respectively.…”

“…Several studies show alterations in the gut microbiota composition of NAFLD patients; however, results are inconsistent. Different analytical methods and study populations might contribute to this inconsistency; culture‐based and culture‐free methods like 16S rRNA gene sequencing as well as whole genome shotgun sequencing were used most widely 2,11,14–24 …”