Synbiotics Alter Fecal Microbiomes, But Not Liver Fat or Fibrosis, in a Randomized Trial of Patients With Nonalcoholic Fatty Liver Disease.

BACKGROUND & AIMS: Dysbiosis of the intestinal microbiota has been associated with nonalcoholic fatty liver disease (NAFLD). We investigated whether administration of a synbiotic combination of probiotic and prebiotic agents affected liver fat content, biomarkers of liver fibrosis, and the composition of the fecal microbiome in patients with NAFLD. METHODS: We performed a double-blind phase 2 trial of 104 patients with NAFLD in the United Kingdom. Participants (mean age, 50.8 ± 12.6 years; 65% men; 37% with diabetes) were randomly assigned to groups given the synbiotic agents (fructo-oligosaccharides, 4 g twice per day, plus Bifidobacterium animalis subspecies lactis BB-12; n = 55) or placebo (n = 49) for 10-14 months. Liver fat content was measured at the start and end of the study by magnetic resonance spectroscopy, and liver fibrosis was determined from a validated biomarker scoring system and vibration-controlled transient elastography. Fecal samples were collected at the start and end of the study, the fecal microbiome were analyzed by 16S ribosomal DNA sequencing. RESULTS: Mean baseline and end-of-study magnetic resonance spectroscopy liver fat percentage values were 32.3% ± 24.8% and 28.5% ± 20.1% in the synbiotic group and 31.3% ± 22% and 25.2% ± 17.2% in the placebo group. In the unadjusted intention-to-treat analysis, we found no significant difference in liver fat reduction between groups (ß = 2.8; 95% confidence interval, -2.2 to 7.8; P = .30). In a fully adjusted regression model (adjusted for baseline measurement of the outcome plus age, sex, weight difference, and baseline weight), only weight loss was associated with a significant decrease in liver fat (ß = 2; 95% confidence interval, 1.5-2.6; P = .03). Fecal samples from patients who received the synbiotic had higher proportions of Bifidobacterium and Faecalibacterium species, and reductions in Oscillibacter and Alistipes species, compared with baseline; these changes were not observed in the placebo group. Changes in the composition of fecal microbiota were not associated with liver fat or markers of fibrosis. CONCLUSIONS: In a randomized trial of patients with NAFLD, 1 year of administration of a synbiotic combination (probiotic and prebiotic) altered the fecal microbiome but did not reduce liver fat content or markers of liver fibrosis. (ClinicalTrials.gov, Number: NCT01680640).

The characterisation of hepatic mitochondrial function in patients with non-alcoholic fatty liver disease (NAFLD) using the 13C-ketoisocaproate breath test.

Hepatic mitochondrial function (HMF) assessed by the 13C-ketoisocaproate breath test (13C-KICA BT) has been previously shown to be significantly associated with the severity of biopsy proven non-alcoholic fatty liver disease (NAFLD). However, it is uncertain whether any perturbation in HMF relates specifically to severity of liver disease or factors associated with metabolic syndrome within (NAFLD). Our aim was to investigate whether there was any change in HMF assessed by 13C-KICA BT in patients with NAFLD compared to control subjects, and to assess the factors that are independently associated with HMF. METHODS: 77 patients with NAFLD and 11 healthy control subjects were studied. HMF was assessed using 13C-KICA BT and expressed as cumulative % 13C-dose recovered on breath over 1 h (cPDR over 1 h). Liver fat and fibrosis was assessed by transient elastography. Multivariable linear regression modelling was undertaken to test the independence of associations with HMF. RESULTS: HMF (cPDR over 1 h) was lower in NAFLD compared to controls [13.4% (4.8) v. 21.0% (6.3); p < 0.0001)]. In NAFLD, HMF was lower in patients with diabetes versus no diabetes [12.7% (3.4) v. 14.3% (6.1); p = 0.003)]. Regression modelling showed age (ß = -0.08; p = 0.01), waist circumference (ß = -0.08; p = 0.01), hip circumference (ß = -0.04; p = 0.01), aspartate aminotransferase (AST) (ß = -0.05; p = 0.01) and diabetes status (ß = -1.81; p = 0.01) were independently associated with HMF (R2 = 41.5%; p < 0.0001). CONCLUSIONS: In patients with NAFLD (compared to healthy subjects), there was a reduction in HMF assessed by the 13C-KICA BT. Furthermore, in patients with NAFLD, HMF is independent and inversely associated with age, waist and hip circumference, AST and diabetes status.

Design and rationale of the INSYTE study: A randomised, placebo controlled study to test the efficacy of a synbiotic on liver fat, disease biomarkers and intestinal microbiota in non-alcoholic fatty liver disease.

BACKGROUND: Non-alcoholic fatty liver disease (NAFLD) represents a spectrum of fat-related conditions ranging from simple fatty liver, to non-alcoholic steatohepatitis (NASH), fibrosis and cirrhosis. There is growing evidence that NAFLD is a multisystem disease, affecting several extra-hepatic organs and regulatory pathways. Furthermore, since the gut and liver are linked anatomically via the portal vein, disturbances of the gut microbiota (dysbiosis) can affect the liver. OBJECTIVES: In patients with NAFLD, we are testing the effects of a synbiotic which is the combination of a prebiotic (fructooligosaccharides; 4 g/day) and a probiotic (Bifidobacterium animalis subsp. lactis BB-12 at a minimum of 10 billion CFU/day) on a) liver fat percentage, b) NAFLD fibrosis algorithm scores, c) gut microbiota composition. Additionally, there will be several hypothesis-generating secondary outcomes to understand the metaorganismal pathways that influence the development and progression of NAFLD, type 2 diabetes, and cardiovascular risk. DESIGN: In a randomised double-blind placebo-controlled trial, 104 participants were randomised to 10-14 months intervention with either synbiotic (n = 55) or placebo (n = 49). Recruitment was completed in April 2017 and the last study visit will be completed by April 2018. METHODS: Change in gut microbiota composition will be assessed using 16S ribosomal RNA gene sequencing. Change in mean liver fat percentage will be quantified by magnetic resonance spectroscopy (MRS). In addition, change in liver fat severity will be measured using two NAFLD fibrosis algorithm scores. The INSYTE study was approved by the local ethics committee (REC: 12/SC/0614) and is registered at www.clinicaltrials.gov as NCT01680640.