An oat drink fermented by lactobacillus plantarum reduces formation of liver fibrosis via beneficial effects on the gut microbiome and circulating bile acids in patients with advanced alcohol-related liver disease: a 24-week randomized controlled trial

Background: Gut dysbiosis and permeability are suggested treatment targets for alcohol-related liver disease (ArLD). ReFerm®, a post-biotic drink made from an oat composition fermented with Lactobacillus plantarum 299v, improves the gut barrier in patients with irritable bowel syndrome. We investigated the effect of ReFerm® on formation of liver fibrosis by hepatic stellate cell activity, composition of gut microbiome, and circulatory bile and amino acids in patients with compensated advanced chronic liver disease (cACLD) related to alcohol. Methods: We randomized 56 patients with cACLD 1:1 to receive ReFerm® or Fresubin®, a medical protein-rich supplement, for 24 weeks, with liver biopsies, plasma, and stool collected at baseline and end-of-treatment. We assessed hepatic stellate cell activity by immunohistochemistry of liver biopsies for quantification of α-smooth muscle actin (α-SMA) using automated digital imaging analysis. Primary outcome was ≥10% reduction in α-SMA. Compliance was assessed every two weeks. Microbiome composition was analyzed by shotgun metagenomics, and concentrations of plasma amino- and bile acids were obtained by liquid chromatography-mass spectrometry (LC-QQQ, Agilent). To facilitate comparison across outcome measures, the treatment effect was standardized as Cohens d. Results: Median age was 63 years (57-67), most patients were male (83%) mainly with cirrhosis (F2/F3/F4=4/15/33). Baseline alcohol intake was 36 grams/day, comparable between groups during the study. Thirteen in the ReFerm® group and 18 in the Fresubin® group achieved high compliance (>85%). In the Referm® group, 8/20 (40%) of patients improved ≥10% in α-SMA compared to 4/20 (20%) in the Fresubin® group (OR=2.3; 95%CI 0.6-9.5; p=0.246). In patients with high compliance, ReFerm® significantly improved α-SMA compared to Fresubin® (OR=5.6; 95%CI 1.2-27.1; p=0.032). Increasing compliance of ReFerm® correlated with improvements in α-SMA (Rho=-0.6623, P=0.0011). Referm® decreased the abundance of Flavonifractor platii and Veillonella dispar (p=0.0118, p=0.0129), two species that have been associated with liver fibrosis formation. We found a clear tendency of plasma bile acids decreasing in the ReFerm® group compared to the Fresubin® group, a possible sign of better liver performance. The reversed tendency was found within plasma amino acids, as ReFerm® increased amino acids overall compared to the Fresubin® group, hereof four significantly (Taurine (p=0.037), Homocitrulline (p=0.028), L-Isoleucine (p=0.046), and L-Leucine(p=0.039)). There is increasing evidence that these amino acids benefit the liver, especially in the advanced stage of fibrosis. Conclusion: Treatment of advanced ArLD with the post-biotic drink ReFerm® reduces liver fibrosis formation by decreasing α-SMA. ReFerm® may act via a reduction in gut microbes driving fibrogenesis and improvements in circulating bile and amino acids.