Research Article Details

Article ID: A16707
PMID: 28231800
Source: Lipids Health Dis
Title: Dietary intervention, but not losartan, completely reverses non-alcoholic steatohepatitis in obese and insulin resistant mice.
Abstract: BACKGROUND: Dietary intervention is the cornerstone of non-alcoholic steatohepatitis (NASH) treatment. However, histological evidence of its efficacy is limited and its impact on hepatic pathways involved in NASH is underreported. The efficacy of the angiotensin receptor type 1 blocker losartan is controversial because of varying results in a few animal and human studies. We evaluated the effect of dietary intervention versus losartan on NASH and associated systemic metabolic features in a representative mouse model. METHODS: Male C57BL/6&#160;J mice with high fat-high sucrose diet (HF-HSD) induced NASH, obesity, insulin resistance and hypercholesterolemia were subjected to dietary intervention (switch from HF-HSD to normal chow diet (NCD)) (n&#8201;=&#8201;9), continuation HF-HSD together with losartan (30&#160;mg/kg/day) (n&#8201;=&#8201;9) or continuation HF-HSD only (n&#8201;=&#8201;9) for 8&#160;weeks. 9 mice received NCD during the entire experiment (20&#160;weeks). We assessed the systemic metabolic effects and performed a detailed hepatic histological and molecular profiling. A P-value of&#8201;<&#8201;0.05, using the group with continuation of HF-HSD only as control, was considered as statistically significant. RESULTS: Dietary intervention normalized obesity, insulin resistance, and hypercholesterolemia (for all P&#8201;<&#8201;0.001), and remarkably, completely reversed all histological features of pre-existent NASH (for all P&#8201;<&#8201;0.001), including fibrosis measured by quantification of collagen proportional area (P&#8201;<&#8201;0.01). At the hepatic molecular level, dietary intervention targeted fibrogenesis with a normalization of collagen type I alpha 1, transforming growth factor &#946;1, tissue inhibitor of metalloproteinase 1 mRNA levels (for all P&#8201;<&#8201;0.01), lipid metabolism with a normalization of fatty acid translocase/CD36, fatty acid transport protein 5, fatty acid synthase mRNA levels (P&#8201;<&#8201;0.05) and markers related to mitochondrial function with a normalization of hepatic ATP content (P&#8201;<&#8201;0.05) together with sirtuin1 and uncoupling protein 2 mRNA levels (for both P&#8201;<&#8201;0.001). Dietary intervention abolished p62 accumulation (P&#8201;<&#8201;0.01), suggesting a restoration of autophagic flux. Losartan did not significantly affect obesity, insulin resistance, hypercholesterolemia or any histological NASH feature. CONCLUSIONS: Dietary intervention, and not losartan, completely restores the metabolic phenotype in a representative mouse model with pre-existent NASH, obesity, insulin resistance and hypercholesterolemia.
DOI: 10.1186/s12944-017-0432-7