Effects of low-calorie diet on steatohepatitis in rats with obesity and hyperlipidemia

Transcriptomics Dissection of Calorie Restriction and Exercise Training in Brown Adipose Tissue and Skeletal Muscle

Calorie restriction (CR) and exercise training (EX) are two critical lifestyle interventions for the prevention and treatment of metabolic diseases, such as obesity and diabetes. Brown adipose tissue (BAT) and skeletal muscle are two important organs for the generation of heat. Here, we undertook detailed transcriptional profiling of these two thermogenic tissues from mice treated subjected to CR and/or EX. We found transcriptional reprogramming of BAT and skeletal muscle as a result of CR but little from EX. Consistent with this, CR induced alterations in the expression of genes encoding adipokines and myokines in BAT and skeletal muscle, respectively. Deconvolution analysis showed differences in the subpopulations of myogenic cells, mesothelial cells and endogenic cells in BAT and in the subpopulations of satellite cells, immune cells and endothelial cells in skeletal muscle as a result of CR or EX. NicheNet analysis, exploring potential inter-organ communication, indicated that BAT and skeletal muscle could mutually regulate their fatty acid metabolism and thermogenesis through ligands and receptors. These data comprise an extensive resource for the study of thermogenic tissue molecular responses to CR and/or EX in a healthy state.

Antioxidative potential and ameliorative effects of green lentil (Lens culinaris M.) sprouts against CCl4-induced oxidative stress in rats

The present study is aimed to investigate the antioxidative potential and ameliorative effects of Lens culinaris Medikus sprouts hydroalcoholic extract (LSHE) on CCl4-induced oxidative stress in rats. The research has been carried out in two successive stages. Firstly, the highest phenolic content and antioxidant activity of L. culinaris sprouts were assessed at 20 ± 1°C and 90-93% RH during sprouting. Total phenolic content (TPC), total carotenoids (TC), total flavonoids (TF), total flavonols (TFL), DPPH-RSA, and vitamin C contents of L. culinaris seeds and 6-days sprouts were determined. Subsequently, phenolics by HPLC analysis of L. culinaris seeds, 3rd and 6th-day sprouts were identified and quantified. Results indicated that 6th-day sprouts contained considerable phenolics with superior antioxidant capacity, thus selected to be examined for biological activity in a rat's module consisting of five groups. G1, normal rats orally received distilled water. G2 received 1.0 mL kg-1 of CCl4 and olive oil (1:1) intraperitoneally (i.p.) twice a week. G3 received CCl4 (i.p.) and 50 mg GAE kg-1 of LSHE daily/orally. G4 received CCl4 (i.p.) 100 mg kg-1 of LSHE orally/daily. G5 (reference group) treated by intramuscular injection (i.m.) of vit. E+Selenium (Vit. E+Se, 50 mg kg-1 twice a week). The weight gain, relative weight of organs, hypoglycemic and hypolipidemic efficiencies, liver's and kidneys' functions, and antioxidant biomarkers were examined. LSHE enhanced the weight gain recovery % and significantly reduced fasting blood glucose. The hypolipidemic effect of LSHE was dramatically reduced triglycerides (TG), total cholesterol (CHO), high- and low-density lipoproteins (HDL-c and LDL-c), and very-low-density lipoproteins (VLDL-c). Administration of 50 and 100 LSHE mg kg-1 ameliorated liver and kidney function in dose-dependent manure. Intriguingly, LSHE considerably reduced malondialdehyde (MDA) while significantly raising reduced glutathione (GSH), superoxide dismutase (SOD), and catalase (CAT) in a dose-dependent manner. In conclusion, biochemical examinations confirmed the therapeutic efficacy of LSHE as a functional product. It encouraged us to recommend L. culinaris sprout production for attenuating hepatotoxicity and nephrotoxicity, as well as being beneficial and profitable for controlling oxidative stress complications.

Sodium Butyrate Supplementation Inhibits Hepatic Steatosis by Stimulating Liver Kinase B1 and Insulin-Induced Gene

BACKGROUND AND AIMS

Butyric acid is an intestinal microbiota-produced short-chain fatty acid, which exerts salutary effects on alleviating nonalcoholic fatty liver disease (NAFLD). However, the underlying mechanism of butyrate on regulating hepatic lipid metabolism is largely unexplored.

METHODS

A mouse model of NAFLD was induced with high-fat diet feeding, and sodium butyrate (NaB) intervention was initiated at the eighth week and lasted for 8 weeks. Hepatic steatosis was evaluated and metabolic pathways concerning lipid homeostasis were analyzed.

RESULTS

Here, we report that administration of NaB by gavage once daily for 8 weeks causes an augmentation of insulin-induced gene (Insig) activity and inhibition of lipogenic gene in mice fed with high-fat diet. Mechanistically, NaB is sufficient to enhance the interaction between Insig and its upstream kinase AMP-activated protein kinase (AMPK). The stimulatory effects of NaB on Insig-1 activity are abolished in AMPKα1/α2 double knockout (AMPK-/-) mouse primary hepatocytes. Moreover, AMPK activation by NaB is mediated by LKB1, as evidenced by the observations showing NaB-mediated induction of phosphorylation of AMPK, and its downstream target acetyl-CoA carboxylase is diminished in LKB1-/- mouse embryonic fibroblasts.

CONCLUSIONS

These studies indicate that NaB serves as a negative regulator of hepatic lipogenesis in NAFLD and that NaB attenuates hepatic steatosis and improves lipid profile and liver function largely through the activation of LKB1-AMPK-Insig signaling pathway. Therefore, NaB has therapeutic potential for treating NAFLD and related metabolic diseases.

The functional nutritional and regulatory activities of calcium supplementation from eggshell for obesity disorders management

The present study was to investigate the effective role of renewable sources of Ca⁺² from eggshell (ES) with different doses to restrict obesity disorders. Rats were classified as follows, G₁ : normal diet for 26 weeks; G₂ : high-fat diet (HFD) for 26 weeks; G₃ , G₄ , and G₅ were supplemented with HFD for 16 weeks and treated with 7.2 g Ca⁺² ES/Kg rat chow, 18 g Ca⁺² ES/Kg rat chow, and 2% diet containing fat (DCF), respectively, for the remaining 10 weeks. Results revealed a significant effect of the low dose of Ca⁺² supplement in form of ES than high dose and 2% DCF; on basis of anthropometric parameters, lipid, leptin, adiponectin, thyroid hormones, Ca⁺² , 25-hydroxyl vitamin-D, and oxidative and inflammatory parameters were regulated. Results were confirmed with the histopathological study. Therefore, it was concluded that Ca⁺² supplementation can be used as a beneficial source for obesity management with anticholesterol actions. PRACTICAL APPLICATIONS: Obesity represented public health hazards. The eggshell is one of the waste products that contain a high percentage of Ca⁺² . The current data exposed using a low dose of ES as a new source of Ca⁺² supplement for treatment of HFD rats leads to significant enhancement of lipid profiles, liver enzymes, kidney functions, leptin, adiponectin, Ca⁺² , 25(OH)-D, TSH, fT_4, and PTH levels. Also, there was a reduction in weight gain, Bwt, BMI, BG, insulin, and HOMA-IR. Moreover, the oxidant-pro-oxidant system was improved in both hepatic and adipose tissues where NO and TBARS concentrations were diminished, and SOD specific activity was elevated. Additionally, TNF-α and ADAM17 expression were downregulated. Hence, it was concluded that there was good evidence that diets supplemented with ES were associated with the reduction of obesity complications especially regulating fat processing and storage in the body.

Indole-3-propionic acid inhibits gut dysbiosis and endotoxin leakage to attenuate steatohepatitis in rats

Microbial metabolites have emerged as critical components that mediate the metabolic effects of the gut microbiota. Here, we show that indole-3-propionic acid (IPA), a tryptophan metabolite produced by gut bacteria, is a potent anti-non-alcoholic steatohepatitis (NASH) microbial metabolite. Here, we demonstrate that administration of IPA modulates the microbiota composition in the gut and inhibits microbial dysbiosis in rats fed a high-fat diet. IPA induces the expression of tight junction proteins, such as ZO-1 and Occludin, and maintains intestinal epithelium homeostasis, leading to a reduction in plasma endotoxin levels. Interestingly, IPA inhibits NF-κB signaling and reduces the levels of proinflammatory cytokines, such as TNFα, IL-1β, and IL-6, in response to endotoxin in macrophages to repress hepatic inflammation and liver injury. Moreover, IPA is sufficient to inhibit the expression of fibrogenic and collagen genes and attenuate diet-induced NASH phenotypes. The beneficial effects of IPA on the liver are likely mediated through inhibiting the production of endotoxin in the gut. These findings suggest a protective role of IPA in the control of metabolism and uncover the gut microbiome and liver cross-talk in regulating the intestinal microenvironment and liver pathology via a novel dietary nutrient metabolite. IPA may provide a new therapeutic strategy for treating NASH.

A molecule made by beneficial microbes in the gut helps protect against a severe form of fatty liver disease by preventing bacterial toxins from leaking out of the intestines into the bloodstream. A research team in China led by Yu Li from the Shanghai Institute of Nutrition and Health (CAS) and Jian-Gao Fan from Xinhua Hospital (SJTU) showed in a rat model of non-alcoholic steatohepatitis that indole-3-propionic acid (IPA), a metabolite produced by gut bacteria, helps maintain the integrity of the intestinal inner lining. The more robust intestinal barrier ensures that bacterial toxins do not enter the bloodstream and eventually reach the liver, where they can trigger injury-inducing inflammation. The findings reveal an interaction between the gut microbiome and the liver, and suggest a role for IPA in the treatment of fatty liver disease.

Diet Consisting of Balanced Yogurt, Fruit, and Vegetables Modifies the Gut Microbiota and Protects Mice against Nonalcoholic Fatty Liver Disease

BACKGROUND

Calorie restriction (CR) is a therapeutically effective method for nonalcoholic fatty liver disease. However, the compliance of the CR method is relatively poor. New CR methods are needed.

METHODS AND RESULTS

Each week, mice are given a 5-day high-fat diet (HFD) ad libitum plus 2 days of an intermittent calorie restriction (ICR) diet (50% calorie restriction) consisting of yogurt, fruit, and vegetables, for 16 weeks. The effect of the ICR diet model on the fatty liver of mice is examined. Compared with continuous HFD-fed mice, the mice feeding HFD+ICR have lower body weight and hepatic steatosis, reduced serum lipid and transaminase levels, increased fatty acid oxidation gene of Cpt1a, and decreased hepatic lipid synthesis gene of Pparγ and Srebf-1c, as well as improved insulin resistance and lower level of inflammation. Moreover, ICR reverses the dysbacteriosis in HFD group, including the lower Shannon diversity indexes and lower abundance of Lactobacillus.

CONCLUSION

An ICR diet consisting of yogurt, fruit, and vegetables attenuates the development of HFD-induced hepatic steatosis in mice. Furthermore, HFD+ICR diet is associated with a different fecal microbiota that tends to be more similar to normal diet controls.

Trimethylamine N-oxide attenuates high-fat high-cholesterol diet-induced steatohepatitis by reducing hepatic cholesterol overload in rats

BACKGROUND

Trimethylamine N-oxide (TMAO) has been shown to be involved in cardiovascular disease (CVD). However, its role in nonalcoholic steatohepatitis (NASH) is unknown.

AIM

To determine the effect of TMAO on the progression of NASH.

METHODS

A rat model was induced by 16-wk high-fat high-cholesterol (HFHC) diet feeding and TMAO was administrated by daily oral gavage for 8 wk.

RESULTS

Oral TMAO intervention attenuated HFHC diet-induced steatohepatitis in rats. Histological evaluation showed that TMAO treatment significantly alleviated lobular inflammation and hepatocyte ballooning in the livers of rats fed a HFHC diet. Serum levels of alanine aminotransferase and aspartate aminotransferase were also decreased by TMAO treatment. Moreover, hepatic endoplasmic reticulum (ER) stress and cell death were mitigated in HFHC diet-fed TMAO-treated rats. Hepatic and serum levels of cholesterol were both decreased by TMAO treatment in rats fed a HFHC diet. Furthermore, the expression levels of intestinal cholesterol transporters were detected. Interestingly, cholesterol influx-related Niemann-Pick C1-like 1 was downregulated and cholesterol efflux-related ABCG5/8 were upregulated by TMAO treatment in the small intestine. Gut microbiota analysis showed that TMAO could alter the gut microbial profile and restore the diversity of gut flora.

CONCLUSION

These data suggest that TMAO may modulate the gut microbiota, inhibit intestinal cholesterol absorption, and ameliorate hepatic ER stress and cell death under cholesterol overload, thereby attenuating HFHC diet-induced steatohepatitis in rats. Further studies are needed to evaluate the influence on CVD and define the safe does of TMAO treatment.

Volatile Oil of Amomum villosum Inhibits Nonalcoholic Fatty Liver Disease via the Gut-Liver Axis

Background

The dried mature fruit of Amomum villosum has been historically used in China as food and in the auxiliary treatment of digestive system disorders. Numerous studies have shown that gastrointestinal function is closely related to the development of nonalcoholic fatty liver disease via the “gut-liver” axis.

Objective

The present study aimed to explore whether the mechanism underlying the regulation of lipid accumulation in nonalcoholic fatty liver disease (NAFLD) may affect related disorders using the active ingredients in A. villosum.

Design

Male Sprague-Dawley rats on a high-fat diet (HFD) to induce NAFLD were administered water extract of A. villosum (WEAV), volatile oil of A. villosum (VOAV), or bornyl acetate. After treatment, serum and liver total cholesterol (TC), triglyceride (TG), free fatty acid (FFA), aspartate aminotransferase (AST), alanine aminotransferase (ALT), high-density lipoprotein cholesterol (HDL-C), and low-density lipoprotein cholesterol (LDL-C) levels were measured. The regulatory role of A. villosum in the microecology of the intestines was assessed using the V4 region of the 16S rDNA sequencing. The expression of the intestinal tight junction proteins occludin and ZO-1 was also measured. The influence of A. villosum on TLR4-mediated chronic low-grade inflammation was evaluated based on the concentrations of key proteins of the TLR4/NF-кB signaling pathway. Results. A. villosum effectively inhibited endogenous lipid synthesis, reduced TG, TC, and FFA accumulation, regulated the expression of LDL-C, and decreased lipid accumulation in liver tissues. VOAV effectively regulated the intestinal microflora, improved chronic low-grade inflammation by promoting ZO-1 and occludin protein expressions, and inhibited the TLR4/NF-кB signaling pathway.

Conclusion

The present study provides scientific basis for the potential application of A. villosum in NAFLD prevention and treatment. Additional chemical constituents other than bornyl acetate also contributed to the preventive effects of A. villosum on NAFLD.

Serological and Pathogenic Analyses of Fowl Adenovirus Serotype 4 (FAdV-4) Strain in Muscovy Ducks

Hydropericardium hepatitis syndrome (HHS) is a lethal disease caused by Fowl adenovirus serotype 4(FAdV-4) that mainly infects 3- to 6-week-old broiler chicks. In 2015, an infectious disease characterized similar symptom to HHS in broilers outbroke in commercial duck flocks in Shandong province. FAdV-4 was isolated from naturally infected ducks and determined by polymerase chain reaction (PCR) amplification and DNA sequence analysis. In order to investigate the effect of FAdV-4 infection on muscovy ducks, we determined and characterized the FAdV-4 Isolate, and assessed its pathogenicity. In this study, HHS was respectively reproduced in 5-week-old muscovy duck by intramuscular injection and intranasal inoculation of allantoic fluid containing FAdV-4, ducks in the negative control group were inoculated with allantoic fluids of healthy duck embryos in the same manner. Clinical symptoms, gross and microscopic lesions, cytokines and antibodies, blood biochemical indices were detected and recorded for 12 days after infection. Typical hydropericardium and hepatitis was observed in experimental muscovy duck in the 3rd day post-inoculation (dpi). FAdV-4 can be replicated in tissues and cause pathological damage, especially in the liver and immune organs. Most of the immune-related cytokines and antibodies levels are up-regulated and then decreased, which may be caused by the initial infection and the normal immune response, later the virus caused the immunosuppression and led to the decrease of levels. To the best of our knowledge, this is the first systematic trial of the pathogenicity of FAdV-4 in muscovy ducks mainly based on the serological test, which will provide new insights into the study of the disease.

Effects of mild calorie restriction on lipid metabolism and inflammation in liver and adipose tissue

Calorie restriction (CR) has been reported to improve lipid metabolism and to decrease inflammatory diseases. However, most existing CR models use 30-50% calorie reduction, which is hard to achieve in humans. We investigated the effects of mild CR on lipid metabolism and inflammatory responses. Male C57BL/6 mice were fed control diet (10% kcal fat, Control) or high fat diet (60% kcal fat, HFD) ad libitum or reduced amount of control diet to achieve 15% CR for 16 wks. Body weights, white adipose tissue weights, liver triacylglycerol levels, and serum fetuin-A levels were lower in CR than in the Control. Serum adiponectin levels were higher in CR and lower in HFD compared with the Control. Liver and adipose tissue Mcp-1 mRNA levels were significantly lower in CR compared with the Control. Adipose tissue mRNA levels of Mcp-1, Il-6, Tnf-α and Socs3 were significantly higher in HFD than in the Control and CR, and levels of these negatively correlated with serum adiponectin levels. CR group had the lowest leptin levels and the highest liver Lepr expression, and Lepr mRNA levels positively correlated with liver Socs3 mRNA levels. Our findings showed that mild CR lowered adiposity which resulted in higher adiponectin and lower fetuin-A levels, and might have contributed to alleviation of inflammatory status in the liver and adipose tissue. Furthermore, mild CR might have affected leptin sensitivity by up-regulating Lepr expression.

Naturally Occurring Stilbenoid TSG Reverses Non-Alcoholic Fatty Liver Diseases via Gut-Liver Axis

The gut-liver axis is largely involved in the development of non-alcoholic fatty liver disease (NAFLD). We investigated whether 2, 3, 5, 4'-tetrahydroxy-stilbene-2-O-β-D-glucoside (TSG) could reverse NAFLD induced by a high-fat diet (HFD) and whether it did so via the gut-liver axis. Results showed that TSG could reduce the accumulation of FFA and it did so by reducing the expression of L-FABP and FATP4. TSG regulated gut microbiota balanced and increased the protein expression of ZO-1 and occludin, which could improve the function of the intestinal mucosal barrier and reduce serum LPS content by about 25%. TSG reduced TL4 levels by 56% and NF-κB expression by 23% relative to the NAFLD model group. This suggests that prevention of NAFLD by TSG in HFD-fed rats is mediated by modulation of the gut microbiota and TLR4/NF-κB pathway, which may alleviate chronic low-grade inflammation by reducing the exogenous antigen load on the host.

Effect of the prolonged high-fat diet on the fatty acid metabolism in rat blood and liver

BACKGROUND

Contradictory data on consequences of prolonged high-fat diet requires a detailed study of the influence of nutritional high-fat load mechanisms on the peculiarity of lipid metabolism in blood and liver. The present study was undertaken to investigate the fatty acid composition of polar and neutral lipids of the blood plasma, erythrocytes and liver in Wistar rats under the conditions of a prolonged high-fat diet.

METHODS

The study was conducted on 60 adult white male Wistar rats. The animals were fed on a high-fat diet consisted of the beef fat and cholesterol (19% and 2% of the total diet, respectively) up to 180 days. The fatty acid composition of the polar and neutral lipids of plasma, erythrocytes and liver were analyzed by the gas chromatography. Statistical data processing was performed by the methods of descriptive statistics with Statistica 6.0.

RESULTS

The prolonged unbalanced diet rich in cholesterol and saturated fatty acids resulted in compensatory biosynthesis of the fatty acids in the rat's liver, the inhibition of synthesis of apoproteins and lipoproteins, disruption of the active transport of fatty acids to tissue cells. This launched the accumulation of 20:4n-6, 20:5n-3, 22:5n-3, and 22:6n-3 in the liver and blood plasma and deficiency of 18:2n-6, 20:5n-3 and 22:6n-3 in the erythrocytes.

CONCLUSIONS

Adaptive adjustment of lipid metabolism un0064er conditions of the high-fat diet induced inhibition of the formation of lipoproteins (VLDL cholesterol) in the liver, compensatory synthesis of 18:1n-9, 20:5n-3, and 20:3n-6 with primary esterification of PUFA n-3 series to neutral lipids.

The influences of SE infection on layers' production performance, egg quality and blood biochemical indicators

BACKGROUND

Salmonella enterica serovar Enteritidis (SE), as a major cause of foodborn illness, infects humans mainly through the egg. However, the symptom of laying hens usually is not typical and hard to diagnosis. In the present study, it is studied that the influences of SE infection on layers' performance, egg quality and blood biochemical indicators. It will help us to improve the strategy to control SE infection in commercial layers. One hundred layers at 20 wk of age were divided into 2 groups, 60 hens for experiment and others for control. The experiment group was fed with the dosage of 108 CFU SE per hen. The specific PCR was used to detect the deposition of SE. On the 8 d after SE infection, 10 hens from the control group and 30 hens from the experimental group were slaughtered to detect the SE colonization. The production performance, egg quality and blood biochemical indices were also analyzed.

RESULTS

The results showed that the colonization rate of SE was highest in caecum contents (55.17%) and lowest in vagina (17.24%). For the eggs the detection rate of SE was highest on the eggshell (80.00%) and lowest in yolk (18.81%). SE infection had no significant influence on production performance and egg qualities (P > 0.05). The difference of laying rate between the experimental and control groups was less than 0.30%, and both were approximately equal to 82.00%. The blood analysis showed that the aspartic aminotransferase (AST) and alanine aminotransferase (ALT) of experimental group was significantly higher than those of control group (P < 0.05). For experimental and control groups AST values were 236.22 U/l and 211.84 U/l respectively, and ALT values were 32.19 U/l and 24.55 U/l. All of coefficients were less than 20%. The colonization of SE in organs increases the enzyme activities of AST and ALT in blood.

CONCLUSIONS

SE in feed could invade the oviduct and infect the forming eggs. It significantly increased the concentration of ALT and AST in blood. However,SE infection was hard to be observed from the appearances of layer and egg. It might be a dangerous risk to human health.

Phospholipid composition of erythrocytes and glutathione redox system in rats during adaptation to cholesterol load

We studied phospholipid composition of erythrocytes and the state of the glutathione redox system in rats during adaptation to cholesterol load for 180 days. The adaptive response is formed during the period from day 30 to day 90 of cholesterol load and is associated with increased relative content of phosphatidylethanolamine and phosphatidylinositol, activation of glutathione redox system enzymes (glutathione reductase and glutathione peroxidase), and enhanced production of glutathione.

Attenuation of high cholesterol-induced oxidative stress in rabbit liver by thymoquinone

BACKGROUND/AIMS

This study examines the modifying effects of thymoquinone (TQ), an agent with antioxidant and hypolipidemic properties, on reactive oxygen species, antioxidant activity, and steatosis in livers of hyperlipidemic rabbit.

METHODS

Oxidative stress was induced in New Zealand White rabbit by a high-cholesterol diet for 8 weeks. Four groups of six animals each were divided into a control group; a high cholesterol group (received 1% cholesterol diet); a high cholesterol/low TQ group (received 1% cholesterol diet plus TQ 10 mg/kg/day), and a high cholesterol/high TQ (20 mg/kg/day) group. Blood samples were taken at the end of the study and examined for fasting serum glucose, insulin, and aminotransaminases. Hepatic tissue samples were examined for malondialdehyde, protein carbonyls, antioxidant enzymes, and steatosis.

RESULTS

There was severe hepatic steatosis and elevated serum alanine aminotransferase in the high cholesterol group (group II) but not in the high cholesterol and low or high TQ groups (groups III, IV). The hepatic reactive oxygen species activity in the high cholesterol group was significantly higher while the antioxidant enzymes were lower (P<0.05) when compared with the control (group I) or either of the high cholesterol and TQ groups.

CONCLUSION

TQ attenuates hepatic oxidative stress in fatty liver injury induced by high-cholesterol diet in rabbits.

Carbon tetrachloride-induced liver disease in rats: the potential effect of supplement oils with vitamins E and C on the nutritional status

The aim of the present investigation was to study the effects of olive oil (OO), corn oil (CO), and flaxseed oil (FO), with or without supplementation of vitamins E and C, on food intake, body weight gain %, liver weight to body weight %, total lipids, liver functions, and liver histology in male rats intoxicated with carbon tetrachloride (CCl(4)). Forty-two rats were divided into two main groups. The first main group was fed on basal diet (BD) as a negative control group (NC). The second main group received subcutaneous injections of CCl(4) in paraffin oil (50% v/v 2 ml/kg) twice a week to induce chronic damage in the liver. The group was then divided into six subgroups, three of which were fed on 4% unsupplemented oils (CO, FO, and OO) as positive control for the three oils used. The rest of the groups were fed on 4% of the same oils supplemented with vitamins E and C. The results of the flaxseed oil rat group indicate that supplementing vitamin E and C led to a significant reduction in the mean values of total cholesterol (TC), low density lipoprotein cholesterol (LDL-C), and liver alanine amino transferase enzyme (ALT). Moreover, it caused an increase of the mean value of high-density lipoprotein cholesterol (HDL-C) as compared to the negative control group (NC). The olive oil group supplemented with the same vitamins showed a significant decrease in the mean value of serum TC and significant (P<0.05) increase in the mean value of serum HDL-C as compared to NC. The results of the corn oil group supplemented with vitamins showed a significant increase in the mean value of serum HDL-C as compared to the negative control group. The histology results confirmed that the group hepatically injured with CCl(4) treatment and fed on supplemented FO or OO showed apparently normal hepatocytes.

CONCLUSION

The most effective treatment was observed with oils supplemented with vitamins E and C. Hierarchically FO achieved the best results compared to other additives, followed by OO and finally CO showing the least effective treatment among the observed groups.

Weight loss, dietary advice and statin therapy in non-alcoholic fatty liver disease: a retrospective study

BACKGROUND

Studies have shown that weight loss can have a favourable effect upon non-alcoholic fatty liver disease (NAFLD). However, the most effective means of achieving weight loss and safety profile of lipid-lowering drugs in the presence of NAFLD is unknown.

AIM

To investigate the effect of dietary advice and lipid-lowering drugs, particularly statins, on patients with NAFLD and dyslipidaemia.

DESIGN

Observational records based study.

METHODS

We studied 71 patients with NAFLD and dyslipidaemia diagnosed and treated between 1996 and 2002 at University Hospital Lewisham. Some were referred to a dietician for weight loss advice as part of their management. After treatment all patients were assessed for changes in weight, serum alanine transaminase (ALT) and serum lipids including serum cholesterol, serum high density lipoprotein (HDL) and serum triglycerides.

RESULTS

Thirty-seven male and 34 female patients with NAFLD and dyslipidaemia were followed up for a mean period of 440 +/- 374 days (median 335). Regression analysis revealed a significant association between changes in weight and changes in serum ALT (p < 0.039). Dietary advice failed to reduce body weight but significantly lowered the serum cholesterol to HDL ratio (p = 0.05). Only 15.4% of patients taking statins experienced a rise in serum ALT > or = 40 U/l, and in each case the rise was transient, returning near baseline or below without discontinuation of statin treatment.

CONCLUSIONS

Weight loss appears to improve NAFLD, and dietary advice and lipid-lowering drugs may be beneficial for patients with NAFLD and dyslipidaemia even if weight loss is not achieved. Statins appear to be safe and efficacious in this group.

Telmisartan, an angiotensin II type 1 receptor blocker, controls progress of nonalcoholic steatohepatitis in rats

The term nonalcoholic steatohepatitis (NASH) has recently been proposed to identify a fatty liver disease accompanied by diffuse fatty infiltration and inflammation. However, no drug therapy has been established for NASH as yet. In the present study, we demonstrate the effect of the angiotensin II type 1 receptor antagonist telmisartan on the development of NASH in a rat model. Telmisartan, but not the angiotensin receptor antagonist valsartan, markedly attenuated hepatic steatosis, inflammation, and fibrosis in these rats. The quantitative parameters of steatosis, inflammation, and fibrosis were also ameliorated by treatment with telmisartan. Compared with telmisartan, the peroxisome proliferator-activated receptor-gamma agonist pioglitazone attenuated hepatic steatosis and fibrosis of the liver to a similar degree. However, telmisartan, but not pioglitazone, dramatically decreased both subcutaneous and visceral fat. In conclusion, these results indicated that telmisartan should be the drug of first choice for the treatment of patients with NASH.

N-acetylcysteine attenuates oxidative stress and liver pathology in rats with non-alcoholic steatohepatitis

AIM: To evaluate attenuating properties of N-acetylcysteine (NAC) on oxidative stress and liver pathology in rats with non-alcoholic steatohepatitis (NASH).

METHODS: Male Sprague-Dawley rats were randomly divided into three groups. Group 1 (control, n = 8) was free accessed to regular dry rat chow (RC) for 6 wk. Group 2 (NASH, n = 8) was fed with 100% fat diet for 6 wk. Group 3 (NASH + NAC₂₀, n = 9) was fed with 100% fat diet plus 20 mg/kg per day of NAC orally for 6 wk. All rats were sacrificed to collect blood and liver samples at the end of the study.

RESULTS: The levels of total glutathione (GSH) and hepatic malondialdehyde (MDA) were increased significantly in the NASH group as compared with the control group (GSH; 2066.7 ± 93.2 vs 1337.5 ± 31.5 μmol/L and MDA; 209.9± 43.9 vs 3.8 ±1.7 μmol/g protein, respectively, P < 0.05). Liver histopathology from group 2 showed moderate to severe macrovesicular steatosis, hepatocyte ballooning, and necroinflammation. NAC treatment improved the level of GSH (1394.8 ± 81.2 μmol/L, P < 0.05), it did not affect MDA (150.1 ± 27.0 μmol/g protein), but led to a decrease in fat deposition and necroinflammation.

CONCLUSION: NAC treatment could attenuate oxidative stress and improve liver histology in rats with NASH.

The effects of rosiglitazone, metformin, and diet with exercise in nonalcoholic fatty liver disease

Our aim was to evaluate effects of metformin, rosiglitazone, and diet with exercise in nonalcoholic fatty liver disease. Forty-seven patients (mean age, 44+/-10 years; 17 female) whose ALT levels had been high for at least 6 months and with hepatosteatosis detected by liver biopsy and/or USG were enrolled in this study. Of these, 12 were treated with 850 mg/day metformin (group 1), 11 with 4 mg/day rosiglitazone (group 2), and 24 with diet and exercise (group 3) for 1 year. ALT normalization at months 6 and 12 was accepted as treatment response. Liver biopsy was performed in all patients in groups 1 and 2 before treatment and 12 patients (4 in group 1, 8 in group 2) after treatment; but in group 3 it was performed only in patients who approved this procedure (12 patients). Body mass index did not change in groups 1 and 2, but it decreased significantly in group 3 (30+/-3 to 28+/-2 kg/m(2)) at month 12. Treatment response rate was 33.3, 54.5, and 54.2% in groups 1, 2, and 3, respectively, at month 6. This rate was 22.2, 37.5, and 41.2 in groups 1, 2, and 3, respectively, at month 12. Rate of steatosis and stage of fibrosis did not change after treatment. Diet with exercise seems to be superior to metformin and rosiglitazone. Decreasing treatment response at month 12 compared to month 6 may be due to fluctuations of ALT levels. Treatment response should be evaluated histologically.

The expression of SIRT1 in nonalcoholic fatty liver disease induced by high-fat diet in rats

OBJECTIVE

SIRT1 is an NAD(+)-dependent deacetylase and its enzymatic activity may be regulated by cellular energy. SIRT1 overexpression reduces the level of oxygen consumption, which is correlative with nonalcoholic fatty liver disease (NAFLD). To elucidate the role of SIRT1 on the development of NAFLD, we investigated the expression of SIRT1 in NAFLD induced by high-fat diet in rats and the effects of calorie restriction.

METHODS

Thirty-one male Wistar rats were divided at random into four groups. The rats in the normal control group NC (n=7) and in the NAFLD model group HF (n=9) were fed ad libitum with normal chow and high-fat diet, respectively, for 3 months, the rats in the calorie restriction (CR) group HCR (n=9) were fed with a high-fat diet for 2 months and then 60% CR with normal chow for 1 month, and the rats in group CRH (n=6) were firstly fed with 60% CR with normal chow for 1 month and then fed a high-fat diet for 2 months. At the end of the experiment, some parameters and expressions of SIRT1 were detected.

RESULTS

The rats in group HF displayed NAFLD. Compared with group NC, the expression of SIRT1 protein was significantly decreased (P<0.01). However, the lower body weight and visceral fat mass of rats in group HCR were showed. Compared with group HF, CR increased the expression of SIRT1 in liver significantly (P<0.01). Consequently, the ultramicropathology changes of NAFLD prominently improved in this group. Meanwhile, the rats in group CRH displayed higher expression of SIRT1 protein and very gentle pathology changes of NAFLD.

CONCLUSION

The expression of SIRT1 is reduced significantly in NAFLD induced by high-fat diet in rats. CR increase-SIRT1 protein expression may be an important mechanism by which CR improves NAFLD.

A growing burden: the pathogenesis, investigation and management of non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD) is the most common hepatic disorder in western countries, and its incidence is increasing. This review outlines the significant health burden posed by NAFLD and discusses what is presently known about its pathogenesis, including the roles of the metabolic syndrome, obesity, insulin resistance, hepatic steatosis, reactive oxygen species, inflammatory cytokines and adipocytokines. The way in which NAFLD is clinically diagnosed is described, and areas of uncertainty surrounding its investigation are identified, before discussing the relative merits of the limited treatment options available and looking ahead to potential therapeutic strategies for the future.

Monounsaturated fat decreases hepatic lipid content in non-alcoholic fatty liver disease in rats

AIM: To evaluate the effects of different types of dietary fats on the hepatic lipid content and oxidative stress parameters in rat liver with experimental non-alcoholic fatty liver disease (NAFLD).

METHODS: A total of 32 Sprague-Dawley rats were randomly divided into five groups. The rats in the control group (n = 8) were on chow diet (Group 1), rats (n = 6) on methionine choline-deficient diet (MCDD) (Group 2), rats (n = 6) on MCDD enriched with olive oil (Group 3), rats (n = 6) on MCDD with fish oil (Group 4) and rats (n = 6) on MCDD with butter fat (Group 5). After 2 mo, blood and liver sections were examined for lipids composition and oxidative stress parameters.

RESULTS: The liver weight/rat weight ratio increased in all treatment groups as compared with the control group. Severe fatty liver was seen in MCDD + fish oil and in MCDD + butter fat groups, but not in MCDD and MCDD + olive oil groups. The increase in hepatic triglycerides (TG) levels was blunted by 30% in MCDD + olive oil group (0.59 ± 0.09) compared with MCDD group (0.85 ± 0.04, p < 0.004), by 37% compared with MCDD + fish oil group (0.95 ± 0.07, p < 0.001), and by 33% compared with MCDD + butter group (0.09 ± 0.1, p < 0.01). The increase in serum TG was lowered by 10% in MCDD + olive oil group (0.9 ± 0.07) compared with MCDD group (1.05 ± 0.06). Hepatic cholesterol increased by 15-fold in MCDD group [(0.08 ± 0.02, this increment was blunted by 21% in MCDD + fish oil group (0.09 ± 0.02)]. In comparison with the control group, ratio of long-chain polyunsaturated fatty acids omega-6/omega-3 increased in MCDD + olive oil, MCDD + fish oil and MCDD + butter fat groups by 345-, 30- and 397-fold, respectively. In comparison to MCDD group (1.58 ± 0.08), hepatic MDA contents in MCDD + olive oil (3.3 ± 0.6), MCDD + fish oil (3.0 ± 0.4), and MCDD + butter group (2.9 ± 0.36) were increased by 108%, 91% and 87%, respectively (p < 0.004). Hepatic paraoxonase activity decreased significantly in all treatment groups, mostly with MCDD + olive oil group (-68%).

CONCLUSION: Olive oil decreases the accumulation of triglyceride in the liver of rats with NAFLD, but does not provide the greatest antioxidant activity.

Cholesterol-fed rabbit as a unique model of nonalcoholic, nonobese, non-insulin-resistant fatty liver disease with characteristic fibrosis

BACKGROUND

The number of patients suffering from metabolic syndrome is increasing rapidly. Metabolic syndrome causes severe pathological changes in various organs, including the liver, and its main phenotype is nonalcoholic fatty liver disease (NAFLD). NAFLD has a broad spectrum ranging from simple fatty change to severe steatohepatitis with marked fibrosis. Recently, several experimental animal models for NAFLD have been proposed. However, most were established by rather artificial conditions such as genetic alteration. In the present study, we tried to establish a unique animal model mimicking some of the physiopathological features of NAFLD using high-cholesterol-fed rabbits.

METHODS

Male rabbits fed with standard rabbit food containing 1% cholesterol for 8 weeks and 12 weeks were compared to controls (six rabbits/group). The weight of food was strictly restricted to 100 g/rabbit per day.

RESULTS

Body weights and fasting plasma insulin levels showed no significant differences among the groups. In contrast, characteristic fine fibrosis was extended from perivenular to pericellular areas, and microvesicular fatty change with ballooning degeneration was observed in perivenular areas in livers of the cholesterol-fed rabbits. Increase of serum cholesterol level, activation of hepatic stellate cells, and exposure to oxidative stress were also recognized.

CONCLUSIONS

Cholesterol-fed rabbits share several physiopathological features of NAFLD. Because this model did not show insulin resistance or obesity, it may be useful for elucidating the mechanism of NAFLD related mainly to hyperlipidemia.

Steatosis recovery after treatment with a balanced sunflower or olive oil-based diet: involvement of perisinusoidal stellate cells

AIM

To analyze the relationship between perisinusoidal stellate cell (PSC) activation and the dietary fat quantity and composition in the treatment of hepatic steatosis.

METHODS

Using an experimental rat model of steatosis based on the intake of a hyperlipidic diet (14% fat as olive oil or sunflower oil, HL-O and HL-S, respectively), we analyzed the liver's capability of recovery after the treatment with a normal-lipidic diet (5% fat as olive oil or sunflower oil, NL-O and NL-S, respectively) by immunocytochemical and Western blot analysis of glial fibrillary acidic protein (GFAP) expression in PSCs, collagen quantification and serum aminotransferase determination.

RESULTS

The fatty infiltration in the steatotic livers decreased after the treatment with both NL diets, indicating liver recovery. This decrease was accompanied with a lower collagen deposition and aminotransferase level as well as changes in the PSC population that increased the GFAP expression. The above-mentioned effects were more pronounced in animals fed on NL-O based diet.

CONCLUSION

Treatment with a balanced diet enriched in olive oil contributes to the liver recovery from a steatotic process. The PSC phenotype is a marker of this hepatic-recovery model.

Roles of leptin and stearoyl-CoA desaturase-1 in pathogenesis of nonalcoholic fatty liver disease induced by a fat-rich diet

AIM: To explore the roles of leptin and stearoyl-CoA desaturase-1 (SCD-1) in the formation of nonalcoholic fatty liver disease (NAFLD) induced by a fat-rich diet, and their responses after medication.

METHODS: Forty-two SD rats were divided into control, experimental, and therapeutic group. The rats in the experimental and therapeutic group were fed with a fat-rich diet to establish NAFLD model, and the rats in the therapeutic group were treated with rosiglitazone for 16 wk from the 9th week of the fat-rich diet. The concentration of serum leptin was measured by enzyme linked immunosorbent assay (ELISA). The ratio of liver SCD-1 mRNA to β-actin mRNA was analyzed by real-time fluorescence reverse transcription polymerase chain reaction (RT-PCR).

RESULTS: Diffusive hepatic steatosis was observed under light microscope in the rats fed by the fat-rich diet at 8 wk. The serum leptin level of rats was notably higher in the experimental than that in control group at 8 and 24 wk ( 8 wk: 5.29±1.83 μg/L vs 3.06±1.35 μg/L, P < 0.05; 24 wk: 7.89±3.01 μg/L vs 3.09±1.52 μg/L, P < 0.05), and the ratio of SCD-1 mRNA/β-actin mRNA was significantly decreased (8 wk: 0.37±0.25 vs 0.82±0.34, P < 0.05). The concentration of serum leptin in the rosiglitazone treated rats was decreased as compared with that in the experimental rats (5.95±3.31 μg/L vs 7.89±3.01 μg/L, P>0.05), and the expression of SCD-1 mRNA in liver were increased (SCD-1/β-actin: 1.02±0.11 vs 0.52±0.22, P < 0.01).

CONCLUSION: A fat-rich diet can lead to the increase of serum leptin, which may promote the formation of NAFLD by down-regulation of SCD-1. Rosiglitazone can decrease the level of serum leptin, so as to protect the liver against NAFLD to some extent.

Hepatocyte Mitochondrial Injury and the Change of Adenosine Triphosphate Storage in Rat Nonalcoholic Steatohepatitis

AIM: To investigate the mitochondrial injury and change in adenosine triphosphate (ATP) storage in a rat model of nonalcoholic steatohepatitis (NASH) induced by fat-rich diet.

METHODS: Seventy-two male SD rats were randomly divided into two groups. The control group (n = 24) was fed with normal diet; the model group (n = 48) was fed with fat-rich diet, which is consisted of 10% lard oil + 2% cholesterol. 6 or 12 rats were sacrificed at the 8^th, 12^th, 16^th and 24^th wk of the experiment. Serum biochemical parameters were measured by a commercial laboratory. The hepatic histologic change was evaluated by light microscopy and transmission electron microscopy. The ATP content was measured by luciferin-luciferase method.

RESULTS: Simple fatty liver was observed in the model group at the 8^th wk. From the 12^th wk to 24^th wk, the liver gradually progressed to steatohepatitis. The ATP content of the liver was reduced in the model group compared with normal group at the 16^th wk [(2.97±0.48)10^-8 μmol/g vs (2.25±0.55)10^-8 μmol/g, P = 0.0 361, t = 2.354] and the 24^th wk [(2.97±0.48)10^-8 μmol/g vs (1.99±0.66)10^-8 μmol/g, P = 0.0 053, t = 3.439]. Markedly abnormal morphology was observed in the hepatocyte mitochondria in model group, including swelling, rounding, loss of cristae, and stacks of intramitochondrial paracrystalline inclusion bodies.

CONCLUSION: The hepatocytic mitochondria in NASH were injured and the storage of ATP was reduced, which may contribute to the pathogenesis of NASH.

Effects of emodin on treating murine nonalcoholic fatty liver induced by high caloric laboratory chaw

AIM: To investigate the effects of emodin on the treatment of non-alcoholic fatty liver in rats induced by high caloric laboratory chaw.

METHODS: Non-alcoholic fatty liver model was successfully established by feeding with high caloric laboratory chaw for 12 wk. Then the model rats were randomly divided into 3 groups, namely model control group, emodin group and dietary treatment group. The rats in emodin group were given emodin at dose of 40 mg/(kg·d) while animals in other groups were given distilled water of the same volume. The rats in model control group were fed with high caloric laboratory chaw while animals in other groups were fed with normal diet. Four weeks later, liver index (liver/body weight ratio), serum activities of liver-associated enzymes, blood lipid, fasting blood glucose, fasting plasma insulin, HOMA insulin resistance index (HOMA-IR), hepatic triglyceride content and histology features of all groups were assayed. The expression of hepatic peroxisomal proliferator activated receptor (PPAR) gamma was determined by RT-PCR.

RESULTS: The body weight, liver index, serum activities of alanine aminotransferase (ALT), blood lipid, hepatic triglyceride content of model control group were significantly elevated, with moderate to severe hepatocyte steatosis. The expression of hepatic PPAR gamma mRNA was obviously reduced in model control group. Compared with model control group, the body weight, liver index, serum activities of ALT, blood lipids and hepatic triglyceride of emodin group significantly decreased and hepatic histology display was also greatly improved. Meanwhile, the expression of hepatic PPAR gamma mRNA was elevated. However, high serum activities of ALT and hyperlipidemia were persisted in dietary treatment group although liver index was decreased and liver histology was somewhat improved.

CONCLUSION: It is suggested that emodin might be effective in the treatment of non-alcoholic fatty liver in rats. Its therapeutic mechanism could be associated with increasing the expression of hepatic PPAR gamma mRNA.

Effect of Chinese medicine Ganzhifu decoction on murine fatty liver induced by alcohol and high fat feeding

AIM: To explore the effects of Chinese medicine Ganzhifu decoction on fatty liver in rats.

METHODS: The fatty liver model was established by feeding with high caloric laboratory chaw and alcohol. Sixty male Wistar rats were randomized into 6 groups, i.e. a normal control group, a model group, three Ganzhifu groups treated with Ganzhifu decoction (giant knotweed 20 g, rhubarb 5 g, Bupleurum 10 g) in different concentrations and a metformin group. All the animals were killed after treatment for 8 wk. The activities of alkaline phosphatase and gamma glutamyl transferase, blood lipid, liver triglycerin and pathological changes in all groups were assayed.

RESULTS: The activities of alkaline phosphatase and gamma glutamyl transferase, blood lipid, liver triglycerin of model group increased significantly (ALP: 8 156±2 696 vs 4 478±2 229; GGT: 52±14 vs 24±21; TG: 615±106 vs 454±113, P < 0.05; Liver triglycerin: 53±10 vs 27±8, P < 0.01). Liver histology showed mild to moderate steatosis. Those indexes of Ganzhifu groups were significantly lower than those of model group (ALP: 5 666±2 187 vs 8 156±2 696; GGT: 24±14 vs 52±14; TG: 442±148 vs 615±106; Liver triglycerin: 35±4, 36±6, 38±6 vs 53±10, P < 0.05, P < 0.01). The hepatic steatosis was also improved. Liver triglycerin of metformin group was significantly reduced (32±1 vs 53±10, P < 0.01), but there was no significant difference in other indexes between metformin and model groups.

CONCLUSION: Ganzhifu decoction can protect fatty liver in rats.

Association between fatty liver and hyperlipidemia

AIM: To investigate the association between the formation of fatty liver and the phenotypes of hyperlipidemia.

METHODS: A total of 258 patients with hyperlipidemia were found in 413 patients with fatty liver, and 61 cases of hyperlipidemia in non-fatty liver patients were selected randomly as controls. The complications and liver function abnormalities were compared between two groups.

RESULTS: The proportion of hypertriglyceridemia and mixed hyperlipidemia was higher in the patients with fatty liver than non-fatty liver. Odds ratios (OR) of finding fatty liver in the patients with mixed hyperlipidemia and hypertrigly-ceridemia were 5.966 and 2.960 respectively, relative to hypercholesterolemia. The percentage of complications of typeⅡdiabetes mellitus, obesity, hypertension, hyperuris-emia and the evelation of serum alanine aminotransferase (ALT), -glutamyltransferase (GGT) were higher in patients with fatty liver than non-fatty liver. But, there were no differences in coincidence of diabetes mellitus, obesity, hyperten-sion, hyperurisemia, coronary heart disease, choelithiasis among various phenotypes of hyperlipidemia.

CONCLUSION: The pathogenesis of fatty liver can be related to mixed hyperlipidemia and hypertriglyceridemia. The complications of patients with fatty liver may be more common than those with non-fatty liver, but have no differences of complications among various phenotypes of hyperlipidemia.

Anti-obesity Effect of PM-F2-OB, an Anti-obesity Herbal Formulation, on Rats Fed a High-Fat Diet

PM-F2-OB is one of the most well-known traditional herbal medicines that are frequently used for the treatment of obesity in Korea. The anti-obesity effect of PM-F2-OB on rats fed a high-fat diet was investigated through analyses of changes in body weight, kidney fat weight, and blood biochemicals including cholesterol, free fatty acid, BUN, creatinine, HDL, LDL, phospholipids, SGOT, SGPT, total lipids, and triglycerides. The subjects in this study were divided into four groups: a normal group with a standard diet (N); a PM-F2-OB treatment group fed a standard diet (N+PM-F2-OB); a control group fed a high-fat diet (C); and a PM-F2-OB treatment group fed a high-fat diet (C+PM-F2-OB). There were no significant differences in body weight change between the N and N+PM-F2-OB treatments. Also, there was no significant difference in the amount of food intake between the C and C+PM-F2-OB treatments. These results suggest that PM-F2-OB has no significant toxicity and does not induce a dislike for that diet due to its smell or taste. Rats were administered a high-fat diet (20% (w/w)) for six weeks to induce obesity. The study shows that PM-F2-OB significantly prevented increases in body weight, cholesterol, LDL and total lipids that resulted from the high-fat diet. PM-F2-OB also decreased kidney fat weight and free fatty acid, phospholipid, and triglyceride concentrations induced by the high-fat diet to level equals or below the normal diet group. It was concluded from the results that PM-F2-OB has a distinct anti-obesity effect.