Background: Hepatic encephalopathy (HE) is a complex neuropsychiatric syndrome arising from chronic liver disease (CLD). HE manifests with symptoms such as poor memory, impairment in motor coordination, lethargy and coma. The gut microbiota has been shown to influence neurological function and many studies have demonstrated the association between altered microbiota and liver disease. Fecal matter transplantation (FMT) has revealed beneficial effects in clinical studies yet many limitations of these studies render the results inconclusive. Purpose: The aim of this study is to explore the impact of FMT on gut microbiota and the beneficial effects on neuro behaviour in bile-duct ligated (BDL) rats. Method: Male Sprague-Dawley rats were randomly assigned to one of three groups; SHAM (N=10), BDL-VEH (vehicle) (N=9) and BDL-FMT (who received FMT daily from pooled feces from SHAM rats). After five weeks, behaviour analysis was performed to evaluate short and long-term memory (Novel Object Recognition), anxiety (Open Field and Elevated Plus Maze) and motor coordination (Rotarod). Other parameters such as body weight and composition, ascites, gastrocnemius muscle weight and markers of liver function (ALT, AST, bilirubin and NH3) were also measured. Finally, the feces were collected and 16S RNA was sequenced for all groups. Result(s): FMT did not alter body composition (weight, composition, ascites and gastrocnemius muscle weight as well as and degree of liver disease (liver damage markers) in BDL-FMT vs BDL-Vehicle. BDL-VEH developed a loss of short/longterm memory and motor coordination compared to Sham rats. However, alterations in neurological dysfunction were prevented in the BDL-FMT group. The microbiota -diversity was not significantly different between BDL-VEH and SHAM and furthermore, FMT did not impact α-diversity in BDL rats. In contrast, β-diversity of microbiota did significantly differ between all groups (p < 0.05). The relative abundance also was significantly different between all three groups. In the BDL-FMT group, the phylum Firmicutes was found decreased while the Bacteroidetes were increased compared to BDLVEH and SHAM. The genera Bifidobacterium and Lactobacillus significantly increased in both BDL groups, while Akkermansia and Provotellaceae UCO-001 increased only in BDL-FMT rats and Clostridium Senso Stricto increased only in BDL-VEH compared to Shams. Finally, the genus Rombustia was only present in SHAM. Conclusion(s): Our results demonstrate that FMT lead to improvement in memory and motor coordination in BDL rats. The microbiota profile was different between BDL-VEH and SHAM, and FMT lead to further alterations. The fact that FMT did not normalize microbiota profile, suggests BDL-FMT leads to a novel specific microbiota profile which in turn protects the brain. The FMT-induced increase in Akkermansia and Provotellaceae UCO-001 merits to be further investigated in regards to their beneficial neurological effect in CLD.
