Disease Progression and Pharmacological Intervention in a Nutrient-Deficient Rat Model of Nonalcoholic Steatohepatitis

Abstract

Background There is a marked need for improved animal models of nonalcoholic steatohepatitis (NASH) to facilitate the development of more efficacious drug therapies for the disease. Methods Here, we investigated the development of fibrotic NASH in male Wistar rats fed a choline-deficient l -amino acid-defined (CDAA) diet with or without cholesterol supplementation for subsequent assessment of drug treatment efficacy in NASH biopsy-confirmed rats. The metabolic profile and liver histopathology were evaluated after 4, 8, and 12 weeks of dieting. Subsequently, rats with biopsy-confirmed NASH were selected for pharmacological intervention with vehicle, elafibranor (30 mg/kg/day) or obeticholic acid (OCA, 30 mg/kg/day) for 5 weeks. Results The CDAA diet led to marked hepatomegaly and fibrosis already after 4 weeks of feeding, with further progression of collagen deposition and fibrogenesis-associated gene expression during the 12-week feeding period. Cholesterol supplementation enhanced the stimulatory effect of CDAA on gene transcripts associated with fibrogenesis without significantly increasing collagen deposition. Pharmacological intervention with elafibranor, but not OCA, significantly reduced steatohepatitis scores, and fibrosis-associated gene expression, however, was unable to prevent progression in fibrosis scores. Conclusion CDAA-fed rats develop early-onset progressive NASH, which offers the opportunity to probe anti-NASH compounds with potential disease-modifying properties.

Attenuation of the Hepatoprotective Effects of Ileal Apical Sodium Dependent Bile Acid Transporter (ASBT) Inhibition in Choline-Deficient L-Amino Acid-Defined (CDAA) Diet-Fed Mice

“…Although not injurious when hepatic PC synthesis is intact, the ASBTi-induced shift to a more hydrophobic bile acid pool may be injurious under PC-deficient conditions. The absence of beneficial effects in the CDAA model has been noted for other therapeutic interventions such as FXR agonism with obeticholic acid (50). Moreover, feeding a choline-deficient, iron-supplemented L-amino aciddefined diet to rats has been shown to induce a persistent fibrosis, potentially secondary to increased oxidative stress (51).…”

Towards a standard diet-induced and biopsy-confirmed mouse model of non-alcoholic steatohepatitis: Impact of dietary fat source

“…This makes it imperative to control for inherently variable dynamics in NAFLD progression that could otherwise lead to misinterpretation of data obtained in longitudinal studies. Liver biopsy procedures have therefore recently been introduced to prevent bias and enable stringent within-subject analyses in both mice[18,22,23,27] and rats[30].…”

Validity of biopsy-based drug effects in a diet-induced obese mouse model of biopsy-confirmed NASH

“…area or volume fractions) [52], whereas steatosis scores are graded based on the percentage of hepatocytes having lipid droplets, irrespective of the size of the lipid droplets [38]. Similarly, staging of fibrosis is based on the localizations of fibrotic bands, and not the area or thickness of fibrotic bands which is estimated in image analysis [25, 26, 53]. Lastly, scoring of lobular inflammation depends on the number of inflammatory foci (clusters of inflammatory cells) in 200X field of view [38], and not the total content of inflammatory cells (here assessed by gal-3 IHC).…”