Retrorsine Cooperates with Gut Microbiota to Promote Hepatic Sinusoidal Obstruction Syndrome by Disrupting the Gut Barrier

Background and Aims:Hepatic sinusoidal obstruction syndrome(HSOS)is a life-threatening syndrome,and a cause is exposure to pyrrolizidine alkaloid(PA)-containing products.It is well-established that retrorsine(RTS),a rep-resentative Pas,insults hepatic sinusoidal endothelial cells and ensues congestion of hepatic sinusoids.However,little known about the impact of Pas on gut microbiota and intesti-nal barrier and inflammation in HSOS.Methods:Mice were gavaged with or without nonabsorbable antibiotics(ABX),followed by a single dose of RTS.The gut microbiota was examined by 16S rDNA sequencing.Results:ABX pretreat-ment significantly reversed RTS-induced liver damage.RTS altered gut microbiota composition,increasing Gram-nega-tive bacteria and resulting in a sharp elevation of circulating lipopolysaccharides(LPS)in HSOS mice.Gut decontamina-tion with ABX alleviated RTS-induced intestine inflamma-tion,protected against disruption of the intestinal epithelial barrier and gut vascular barrier(GVB),and suppressed he-patic LPS-NF-κB pathway activation in RTS-induced HSOS.Importantly,the LPS level was positively correlated with MELD score in patients with HSOS.Elevated LPS in patients with HSOS confirmed that Gram-negative bacteria were in-volved in the pathogenesis of HSOS.Conclusions:RTS,a PA,cooperated with gut dysbiosis to cause intestinal inflam-mation and gut barrier compromise that increased transport of gut-derived LPS into the liver through the portal vein,which contributed to the pathology of HSOS.Modulating the gut microbiota,protecting the intestinal barrier,and sup-pressing intestinal inflammation with prebiotics or antibiot-ics might be a useful pharmacologic intervention in HSOS.