Fortifying Butterfat with Soybean Oil Attenuates the Onset of Diet-Induced Non-Alcoholic Steatohepatitis and Glucose Intolerance.

The addition of plant oils such as soybean oil (S) to a diet rich in saturated fatty acids is discussed as a possible route to prevent or diminish the development of metabolic disease. Here, we assessed whether a butterfat-rich diet fortified with S affects the development of early non-alcoholic steatohepatitis (NASH) and glucose intolerance. Female C57BL/6J mice were fed a standard-control diet (C); a fat-, fructose-, and cholesterol-rich diet (FFC, 25E% butterfat, 50% (wt./wt.) fructose, 0.16% (wt./wt.) cholesterol); or FFC supplemented with S (FFC + S, 21E% butterfat + 4E% S) for 13 weeks. Indicators of liver damage, inflammation, intestinal barrier function, and glucose metabolism were measured. Lipopolysaccharide (LPS)-challenged J774A.1 cells were incubated with linolenic and linoleic acids (ratio 1:7.1, equivalent to S). The development of early NASH and glucose intolerance was significantly attenuated in FFC + S-fed mice compared to FFC-fed mice associated with lower hepatic toll-like receptor-4 mRNA expression, while markers of intestinal barrier function were significantly higher than in C-fed mice. Linolenic and linoleic acid significantly attenuated LPS-induced formation of reactive nitrogen species and interleukin-1 beta mRNA expression in J774A.1 cells. Our results indicate that fortifying butterfat with S may attenuate the development of NASH and glucose intolerance in mice.

Fortifying diet with rapeseed oil instead of butterfat attenuates the progression of diet-induced non-alcoholic fatty liver disease (NAFLD) and impairment of glucose tolerance.

BACKGROUND: Absolute dietary fat intake but even more so fatty acid pattern is discussed to be critical in the development of non-alcoholic fatty liver disease (NAFLD). Here, we determined if switching a butterfat enriched diet to a rapeseed oil (RO) enriched diet affects progression of an existing NAFLD and glucose intolerance in mice. METHODS: For eight weeks, female C57Bl/6J mice were either fed a liquid control (C) or a butterfat-, fructose- and cholesterol-rich diet (BFC, 25E% butterfat) to induce early signs of steatohepatitis and glucose intolerance in mice. For additional five weeks mice received either BFC or C or a fat-, fructose- and cholesterol-rich and control diet, in which butterfat was replaced with RO (ROFC and CRO). Markers of glucose metabolism, liver damage and intestinal barrier were assessed. RESULTS: Exchanging butterfat with RO attenuated the progression of BFC diet-induced NAFLD and glucose intolerance. Beneficial effects of RO were associated with lower portal endotoxin levels and an attenuation of the induction of the toll-like receptor-4-dependent signaling cascades in liver. Peroxisome proliferator-activated receptor γ activity was induced in small intestine of ROFC-fed mice. CONCLUSION: Taken together, exchanging butterfat with RO attenuated the progression of diet-induced steatohepatitis and glucose intolerance in mice.

Oral arginine supplementation protects female mice from the onset of non-alcoholic steatohepatitis.

Dietary arginine (Arg) supplementation has been proposed to have positive effects on the development of liver diseases. In the present study, we investigate if an oral Arg supplementation in diet protects mice fed a fructose, fat and cholesterol enriched Western-style diet (WSD) from the development of non-alcoholic steatohepatitis (NASH). Female C57BL/6J mice were fed a liquid control diet or a liquid WSD ± Arg (2.49 g/kg body weight/day) for 6 weeks. Indices of liver injury, glucose metabolism and intestinal permeability were determined. While Arg supplementation had no effects on body weight gain, fasting blood glucose levels were significantly lower in WSD+Arg-fed mice than in C+Arg-fed animals. WSD-fed mice developed liver steatosis accompanied with inflammation, both being significantly attenuated in WSD+Arg-fed mice. These effects of Arg supplementation went along with a protection against WSD-induced decreased tight junction protein levels in the upper parts of the small intestine, increased levels of bacterial endotoxin in portal plasma as well as increased hepatic toll-like receptor-4 mRNA and 4-hydroxynonenal protein adduct levels. In conclusion, Arg supplementation may protect mice from the development of NASH.

Oral citrulline supplementation protects female mice from the development of non-alcoholic fatty liver disease (NAFLD).

PURPOSE: Impairments of intestinal barrier function are discussed as risk factors for the development and progression of non-alcoholic fatty liver disease (NAFLD). Studies suggest an association between arginine/citrulline homeostasis and the development of liver damages. Here, the effect of an oral L-citrulline (Cit) supplement on the development of a Western-style diet (WSD)-induced NAFLD was determined in mice. METHODS: Female 6- to 8-week-old C57BL/6J mice were either pair-fed a liquid Western-style or control diet (C) ± 2.5 g/kg bodyweight Cit for 6 weeks (C + Cit or WSD + Cit). Indices of liver damage, glucose metabolism, intestinal barrier function and NO synthesis were measured. RESULTS: While bodyweight gain was similar between groups, markers of glucose metabolism like fasting blood glucose and HOMA index and markers of liver damage like hepatic triglyceride levels, number of neutrophils and plasminogen activator inhibitor-1 protein levels were significantly lower in WSD + Cit-fed mice when compared to WSD-fed mice only. Protein levels of the tight junction proteins occludin and zonula occludens-1 in duodenum were significantly lower in mice fed a WSD when compared to those fed a WSD + Cit (-~70 and -~60 %, respectively, P < 0.05), whereas portal endotoxin levels, concentration of 3-nitrotyrosine protein adducts in duodenum and toll-like receptor-4 mRNA expression in livers of WSD + Cit-fed mice were markedly lower than in WSD-fed mice (-~43 %, P = 0.056; -~80 and -~48 %, respectively, P < 0.05). CONCLUSION: Our data suggest that the protective effects of supplementing Cit on the development of NAFLD in mice are associated with a decreased translocation of endotoxin into the portal vein.

Sodium butyrate protects mice from the development of the early signs of non-alcoholic fatty liver disease: role of melatonin and lipid peroxidation.

Non-alcoholic fatty liver disease (NAFLD) is one of the most common liver diseases worldwide with universally accepted treatments still lacking. Oral supplementation of sodium butyrate (SoB) has been suggested to attenuate liver damage of various aetiologies. Our study aimed to further delineate mechanisms involved in the SoB-dependent hepatic protection using a mouse model of fructose-induced NAFLD and in in vitro models. C57BL/6J mice were either pair-fed a fructose-enriched liquid diet ±0·6 g/kg body weight per d SoB or standard chow for 6 weeks. Markers of liver damage, intestinal barrier function, glucose metabolism, toll-like receptor-4 (TLR-4) and melatonin signalling were determined in mice. Differentiated human carcinoma colon-2 (Caco-2) and J774A.1 cells were used to determine molecular mechanisms involved in the effects of SoB. Despite having no effects on markers of intestinal barrier function and glucose metabolism or body weight gain, SoB supplementation significantly attenuated fructose-induced hepatic TAG accumulation and inflammation. The protective effects of SoB were associated with significantly lower expression of markers of the TLR-4-dependent signalling cascade, concentrations of inducible nitric oxide synthase (iNOS) protein and 4-hydroxynonenal protein adducts in liver. Treatment with SoB increased melatonin levels and expression of enzymes involved in melatonin synthesis in duodenal tissue and Caco-2 cells. Moreover, treatment with melatonin significantly attenuated lipopolysaccharide-induced expression of iNOS and nitrate levels in J774A.1 cells. Taken together, our results indicated that the protective effects of SoB on the development of fructose-induced NAFLD in mice are associated with an increased duodenal melatonin synthesis and attenuation of iNOS induction in liver.

Supplementation of sodium butyrate protects mice from the development of non-alcoholic steatohepatitis (NASH).

Overnutrition, insulin resistance and an impaired intestinal barrier function are discussed as critical factors in the development of non-alcoholic fatty liver disease. Not only butyrate-producing probiotics as well as supplementation of sodium butyrate (SoB) have been suggested to bear protective effects on liver damage of various aetiologies. However, whether an oral consumption of SoB has a protective effect on Western-style diet (WSD)-induced non-alcoholic steatohepatitis (NASH) and if so molecular mechanism involved has not yet been determined. Eight-week-old C57BL/6J mice were pair-fed either a liquid control or WSD±0·6 g/kg body weight SoB. After 6 weeks, markers of liver damage, inflammation, toll-like receptor (TLR)-4 signalling, lipid peroxidation and glucose as well as lipid metabolism were determined in the liver tissue. Tight junction protein levels were determined in the duodenal tissue. SoB supplementation had no effects on the body weight gain or liver weight of WSD-fed mice, whereas liver steatosis and hepatic inflammation were significantly decreased (e.g. less inflammatory foci and neutrophils) when compared with mice fed only a WSD. Tight junction protein levels in duodenum, hepatic mRNA expression of TLR-4 and sterol regulatory element-binding protein 1c were altered similarly in both WSD groups when compared with controls, whereas protein levels of myeloid differentiation primary response gene 88, inducible nitric oxide synthase, 4-hydroxynonenal protein adducts and F4/80 macrophages were only significantly induced in livers of mice fed only the WSD. In summary, these data suggest that an oral supplementation of SoB protects mice from inflammation in the liver and thus from the development of WSD-induced NASH.