Multiple gut–liver axis abnormalities in children with obesity with and without hepatic involvement

Summary Background Gut–liver axis (GLA) dysfunction appears to play a role in obesity and obesity-related hepatic complications. Objectives This study sought to concurrently explore several GLA components in a paediatric obese population with/without liver disease. Methods Thirty-two children (mean age 11.2 years) were enrolled: nine controls with normal weight and 23 patients with obesity (OB+). Of the 23 patients OB(+), 12 had not steatosis (ST−), and 11 had steatosis (ST+) (associated [n = 8] or not [n = 3] with hypertransaminasaemia [ALT +/−]). Subjects were characterized by using auxologic, ultrasonographic and laboratory parameters. A glucose hydrogen breath test was performed to test for small intestinal bacterial overgrowth, a urinary lactulose/mannitol ratio (LMR) was obtained to assess intestinal permeability, and tests for transaminases, blood endogenous ethanol, endotoxin and faecal calprotectin were also conducted. Results Eleven out of 23 patients OB(+) (p  90th percentile of the control group values) LMR, with values paralleling the grade of liver involvement (normal weight < OB[+] < OB[+]ST[+]ALT[−] < OB[+)]ST[+]ALT[+] [p < 0.05]). LMR significantly correlated with ethanolaemia (r = 0.38, p = 0.05) and endotoxaemia (r = 0.48, p = 0.015) concentrations. Increased permeability was a risk factor for the development of steatosis (p < 0.002). SIBO was present only in patients with obesity. Faecal calprotectin concentrations were within normal limits in all subjects. Conclusions Increased permeability, endogenous ethanol and systemic endotoxin concentrations reflect some GLA dysfunction in obesity and its hepatic complications. Pending further results to establish their potential causative roles, the modulation of the GLA appears to represent a possible target for the prevention and treatment of these conditions.