Hepatic encephalopathy (HE) is a neuropsychiatric syndrome in chronic liver disease (CLD/cirrhosis). With an increasing prevalence of obesity-induced cirrhosis and evidence linking blood-derived lipids to neurological impairment, we hypothesize that obesity increases the risk, severity and progression of HE. Aim: Development of an animal model of cirrhosis and obesity to investigate the synergistic effect of obesity and CLD on the development of neurological impairment and HE. M&M: Model of CLD and HE: 6-week bile-duct ligation (BDL) rats and Sham-controls were used. Inducing obesity: High-fat diet (HFD) was given for 3 weeks before BDL or Sham surgery. Obese-BDL received HFD for 3 weeks pre-BDL and regular diet (RD) for 6 weeks post-BDL; Lean-BDL received RD pre-/post-BDL; Lean-Sham received RD pre-/post-Sham. Recognition memory, motor-coordination, muscular-strength and body-composition (fat vs lean mass) were assessed before, 3 and 6 weeks post-surgery. Results: Before surgery, body weight (BW) and fat mass of rats on HFD (Obese-BDL) were increased vs rats on RD (Lean-BDL, Lean-Sham). 3 weeks post-surgery, BW, fat and lean mass were increased in Obese-BDL vs. Lean-BDL. Long-term memory was reduced in Obese-BDL, but not in Lean-BDL, vs. Lean-Sham. 6 weeks post-surgery, similar to Lean-BDL, Obese-BDL lost BW, fat and Lean mass vs. Lean-Sham. Motor-coordination, forelimb strength and long-term memory were impaired in Obese-BDL vs Lean-BDL or Lean-Sham, whereas hind-limb strength and short-term memory were impaired in both Obese- and Lean-BDL. Conclusion: HFD induces obesity features in healthy non-cirrhotic rats. Such effects are maintained in cirrhotic-BDL rats. Interestingly, some neurological impairments are detected in Obese-BDL but not in Lean-BDL rats, while others are exacerbated. A synergistic effect of obesity and CLD accelerates/worsens the disease-associated abnormalities observed in HE, suggesting more susceptibility to poor neurological performance in obese-induced cirrhotic patients.
