Rifaximin prevents ethanol-induced liver injury in obese KK-A^y mice through modulation of small intestinal microbiota signature

Abstract

Exacerbation of alcoholic hepatitis (AH) with comorbid metabolic syndrome is an emerging clinical problem, where microbiota plays a profound role in the pathogenesis. Here, we investigated the effect of rifaximin (RFX) on liver injury following chronic-binge ethanol (EtOH) administration in KK-Ay mice, a rodent model of metabolic syndrome. Female, 8-wk-old KK-Ay mice were fed Lieber–DeCarli diet (5% EtOH) for 10 days, following a single EtOH gavage (4 g/kg body wt). Some mice were given RFX (0.1 g/L, in liquid diet) orally. Small intestinal contents were collected from mice without binge. Intestinal microbiota was quantified using aerobic and anaerobic culturing techniques and further analyzed by 16S rRNA sequencing in detail. EtOH feeding/binge caused hepatic steatosis, oxidative stress, and induction of inflammatory cytokines in KK-Ay mice, which were markedly prevented by RFX treatment. Hepatic mRNA levels for cluster of differentiation 14, Toll-like receptor (TLR) 4, TLR2, and NADPH oxidase 2 were increased following EtOH feeding/binge, and administration of RFX completely suppressed their increase. The net amount of small intestinal bacteria was increased over threefold after chronic EtOH feeding as expected; however, RFX did not prevent this net increase. Intriguingly, the profile of small intestinal microbiota was dramatically changed following EtOH feeding in the order level, where the Erysipelotrichales predominated in the relative abundance. In sharp contrast, RFX drastically blunted the EtOH-induced increases in the Erysipelotrichales almost completely, with increased proportion of the Bacteroidales. In conclusion, RFX prevents AH through modulation of small intestinal microbiota/innate immune responses in obese KK-Ay mice. NEW & NOTEWORTHY Here we demonstrated that rifaximin (RFX) prevents chronic-binge ethanol (EtOH)-induced steatohepatitis in KK-Ay mice. Chronic EtOH feeding caused small intestinal bacterial overgrowth, with drastic alteration in the microbiota profile predominating the order Erysipelotrichales. RFX minimized this EtOH induction in Erysipelotrichales with substitutive increases in Bacteroidales. RFX also prevented EtOH-induced increases in portal lipopolysaccharide, and hepatic cluster of differentiation 14, toll-like receptor (TLR) 2, and TLR4 mRNA levels, suggesting the potential involvement of microbiota-related innate immune responses.

Effective Combination Therapy of Angiotensin-II Receptor Blocker and Rifaximin for Hepatic Fibrosis in Rat Model of Nonalcoholic Steatohepatitis

“…Oxidative stress was increased by CDAA, and ARB administration showed decreased oxidative stress compared to CDAA. And rifaximin prevented oxidative stress caused by alcoholic liver injury [40]. So, in some points, both ARB and rifaximin may reduce oxidative stress, which may lead to improve liver fibrosis.…”

Nonalcoholic fatty liver disease and alcohol-related liver disease: From clinical aspects to pathophysiological insights

“…52 We investigated the alteration in the small intestinal microbiota profile following chronic EtOH feeding in KK-A y mice, and the effect of rifaximin (RFX) on liver injury following chronic/binge administration of EtOH. 53 Treatment with RFX significantly suppressed hepatic steatosis, as well as the increase in oxidative stress and inflammatory cytokines, in KK-A y mice given EtOHfeeding/binge. Chronic EtOH feeding increased the net amount of small intestinal bacteria, but RFX did not prevent this increase.…”

The Role of the Gut Microbiome in Liver Fibrosis

“…Rifaximin is a gastrointestinal selective antibiotic with a wide range of antimicrobial activity, minimal drug interactions and negligible effect on the overall gut microbiome [29] (Table 1). In a study in EtOH-induced liver injury in obese mice, treatment with rifaximin increased proportion of the Bacteroidales and decreased ALT and TG levels via modulation of small intestine [30].…”