Western diet-induced mouse model of non-alcoholic fatty liver disease associated with metabolic outcomes: Features of gut microbiome-liver-adipose tissue axis.

OBJECTIVES: Non-alcoholic fatty liver disease (NAFLD) has a growing epidemiologic and economic burden. It is associated with Western diet (WD) patterns, and its pathogenesis involves metabolic disorders (obesity, dyslipidemia, hyperglycemia, and diabetes) and gut dysbiosis, features that are usually neglected or not reproduced by most animal models. Thus, we established a 6-mo WD-induced NAFLD mouse model associated with metabolic disorder, investigating its main features at the gut microbiome-liver-adipose tissue axis, also evaluating the correlations of gut dysbiosis to the other disease outcomes. METHODS: Male C57 BL6 mice received a high-fat (30% lard and 0.2% cholesterol, ∼57% calories) and sucrose-rich (20%) chow, and a high-sugar solution (23.1 and 18.9 g/L of D-fructose and D-glucose) for 6 mo. RESULTS: The model featured high serum cholesterol levels, glucose intolerance, and hyperinsulinemia. WD intervention resulted in extensive macro/microvesicular liver steatosis and pericellular fibrosis-resembling human disease-accompanied by hepatic stellate cell activation and CD68+ macrophage infiltration, increased protein levels of proinflammatory p65-nuclear factor-κB, interleukin-6 and tumor necrosis factor-α, with decreased antioxidant regulator Nrf2. Mice showed clear obesity with adipocyte hypertrophy, and CD68+macrophage/mast cell infiltration in adipose tissue while a reduction in number of goblet cells was also observed in the small intestine. Moreover, the pyrosequencing of the 16 S ribosomal RNA of gut cecal content showed decreased bacterial diversity, enriched Firmicutes and Proteobacteria, decreased Bacteroidetes and Fusobacteria, and increased ratio of Firmicutes to Bacteroidetes. Bacteroidetes and Bacteroides had the highest number of significant correlations with liver-adipose tissue axis outcomes. In silico analysis of gut microbiome in NAFLD obese patients revealed a depletion in Bacteroides, which also correlated to disease outcomes. CONCLUSION: This mice model gathered suitable phenotypical alterations in gut-liver-adipose tissue axis that resembled NAFLD associated with metabolic disorders in humans and may be considered for preclinical investigation.

Beneficial effects of anthocyanin-rich peels of Myrtaceae fruits on chemically-induced liver fibrosis and carcinogenesis in mice.

Hepatocellular carcinoma (HCC) arising from fibrosis/cirrhosis is the most common type of primary liver cancer. Conversely, a higher intake of fruits and vegetables might play a protective role in HCC risk. Recently, Myrtaceae family tropical fruits have raised great interest due to the high levels of anthocyanins especially in their peels, which are usually discarded upon consumption. Anthocyanins are antioxidant pigments known to have beneficial effects in vivo/in vitro cancer bioassays. Thus, we evaluated whether dietary Myrciaria jaboticaba, Syzygium cumini, and Syzygium malaccense fruit peel powders reduce fibrosis and hepatocarcinogenesis in mice. Female C3H/HeJ mice were submitted to the model of diethylnitrosamine/carbon tetrachloride-induced liver fibrosis and carcinogenesis. Concomitantly, mice received a basal diet containing 2% of M. jaboticaba, S. cumini, or S. malaccense fruit peel powders, obtained by convective drying, for 10 weeks. M. jaboticaba peel powder showed the highest levels of total anthocyanins, while S. cumini peel powder displayed the greatest diversity of these pigments. All Myrtaceae family peel powders reduced the serum levels of the liver injury marker alanine aminotransferase. M. jaboticaba peel feeding reduced the incidence of liver preneoplastic foci, hepatocyte proliferation (Ki-67), and the protein levels of hepato-mitogen tumor necrosis factor-alpha (TNF-α). M. jaboticaba peel feeding also diminished liver lipid peroxidation and increased total glutathione levels. S. cumini peel feeding reduced hepatic collagen, lipid peroxidation, and TNF-α levels while increased catalase activity. Although S. malaccense peel powder, which displayed the lowest anthocyanin levels, decreased oxidative stress, and cytokine levels, no effects were observed on liver fibrosis or preneoplastic lesion outcomes. Findings indicate a protective effect of anthocyanin-rich M. jaboticaba and S. cumini peel powder feeding on preneoplastic lesion development and fibrosis, respectively. Results indicate that differential biological responses may be attributed to distinct anthocyanin profiles and levels, assigning a functional/market value to the underutilized peel fraction.