Effect of HFD/STZ on expression of genes involved in lipid, cholesterol and glucose metabolism in rats

Synbiotic supplementation ameliorates anxiety and myocardial ischaemia-reperfusion injury in hyperglycaemic rats by modulating gut microbiota

Hyperglycaemia, hyperlipidaemia, hypertension and obesity are the main risk factors affecting the development and prognosis of ischaemic heart disease, which is still an important cause of death today. In our study, male Sprague-Dawley rats were fed either a standard diet (SD) or a high fat and high carbohydrate diet (HF-HCD) for 8 weeks and streptozotocin (STZ) was injected at the seventh week of the feeding period. In one set of rats, a mixture of a prebiotic and probiotics (synbiotic, SYN) was administered by gavage starting from the beginning of the feeding period. Experimental myocardial ischaemia-reperfusion (30 min/60 min) was induced at the end of 8 weeks. Hyperglycaemia, hypertension and increased serum low-density lipoprotein levels occurred in SD- and HF-HCD-fed and STZ-treated rats followed for 8 weeks. Increased density of the Proteobacteria phylum was observed in rats with increased blood glucose levels, indicating intestinal dysbiosis. The severity of cardiac damage was highest in the dysbiotic HF-HCD-fed hyperglycaemic rats, which was evident with increased serum creatine kinase-MB (CK-MB), cardiac troponin I (cTnI), tumour necrosis factor-α, and interleukin-6 levels, along with a decrease in ST-segment resolution index. SYN supplementation to either a normal or a high-fat high-carbohydrate diet improved gut dysbiosis, reduced anxiety, decreased CK-MB and cTnI levels, and alleviated myocardial ischaemia-reperfusion injury in hyperglycaemic rats.

Cinnamaldehyde ameliorates STZ-induced diabetes through modulation of autophagic process in adipocyte and hepatic tissues on rats

Type 2 diabetes mellitus is a worldwide public health issue. In the globe, Egypt has the ninth-highest incidence of diabetes. Due to its crucial role in preserving cellular homeostasis, the autophagy process has drawn a lot of attention in recent years, Therefore, the purpose of this study was to evaluate the traditional medication metformin with the novel therapeutic effects of cinnamondehyde on adipocyte and hepatic autophagy in a model of high-fat diet/streptozotocin-diabetic rats. The study was conducted on 40 male albino rats, classified into 2 main groups, the control group and the diabetic group, which was subdivided into 4 subgroups (8 rats each): untreated diabetic rats, diabetic rats received oral cinnamaldehyde 40 mg/kg/day, diabetic rats received oral metformin 200 mg/kg/day and diabetic rats received a combination of both cinnamaldehyde and metformin daily for 4 weeks. The outcomes demonstrated that cinnamaldehyde enhanced the lipid profile and glucose homeostasis. Moreover, Cinnamaldehyde had the opposite effects on autophagy in both tissues; by altering the expression of genes that control autophagy, such as miRNA 30a and mammalian target of rapamycin (mTOR), it reduced autophagy in adipocytes and stimulated it in hepatic tissues. It may be inferred that by increasing the treatment efficacy of metformin and lowering its side effects, cinnamaldehyde could be utilized as an adjuvant therapy with metformin for the treatment of type 2 diabetes.

Mitochondrial transfer restores impaired liver functions by AMPK/ mTOR/PI3K-AKT pathways in metabolic syndrome

AIM

We investigated the effect of mitochondria transfer in high fat diet and streptozotocin (HFD + STZ) induced metabolic syndrome (MeS) in rats. The effect of mitochondria transfer in MeS with co-existing hypertension, hyperlipidaemia, diabetes and fatty liver together, has not been reported.

MATERIALS AND METHODS

Heathy mitochondria was transferred intravenously and the effect on several physiological parameters and biochemical parameters were examined in HFD + STZ rats. In addition, RNA-sequencing of healthy liver tissues was performed to elucidate the molecular pathways affected by mitochondria transfer in restoring metabolic health.

KEY FINDINGS

We observed reduction in both systolic and diastolic blood pressure levels, reduced blood glucose levels, and a marked reduction in serum lipid profiles. The levels of alanine transaminase (ALT) and aspartate transaminase (AST) also improved along with evident restoration of liver morphology demonstrated by histopathological analysis. Enhanced mitochondrial biogenetics and reduction in oxidative stress and inflammatory markers was also observed. The pathway enrichment analysis revealed reduction in insulin resistance, inflammatory markers, regulation of mitochondrial bioenergetics, calcium ion homeostasis, fatty-acid β-oxidation, cytokine immune regulators, and enhanced lipid solubilisation. The significant effect of healthy mitochondria transfer in restoration of metabolic functions was observed by the activation of PI3K-AKT, AMPK/mTOR pathways and cytokine immune regulators, suggesting that inflammatory mediators were also significantly affected after mitochondria transfer.

SIGNIFICANCE

This study, provides insights on molecular processes triggered by mitochondria transfer in fatty liver regeneration and improvement of overall metabolic health.

The hypolipidemic, anti-inflammatory and antioxidant effect of Kavolì® aqueous extract, a mixture of Brassica oleracea leaves, in a rat model of NAFLD

Herein we characterized the bioactive metabolites of the aqueous extract of Kavolì®, a commercial product composed of a mixture of Brassica oleracea leaves, and assessed its potential ameliorating effects in a rat model of non-alcoholic fatty liver disease (NAFLD). Kavolì® extract showed high levels of bioactive compounds and strong in vitro antioxidant activities. Chlorogenic and neochlorogenic acids were identified as the most representative polyphenols. The administration of brassica extract to steatotic rats significantly ameliorated the levels of blood lipids and transaminases, and lipid content and inflammatory markers in liver. Oxidative stress parameters were significantly improved in both liver and brain of steatotic rats. Moreover, plasma and feces levels of short chain fatty acids (SCFAs) were bring back close to control values by Kavolì® treatment, in spite of high fat diet/streptozotocin (HFD/STZ)-induced alterations. The efficacy of Kavolì® in treating hypercholesterolemia, reducing the level of inflammation and cardiovascular disease biomarkers, steatosis and oxidative stress parameters, as well as the ability in modulating SCFAs levels is probably related to the bioactive compounds of the water extract administered to the rat model of NAFLD. In particular, the ameliorating effects are largely attributable to the high content in polyphenols observed in our study.

MiR-203 is an anti-obese miRNA by targeting ASBT

Obesity is characterized by excessive fat deposition within the body. Bile acids (BA) are important regulators for controlling the absorption of lipid. Here we show that miR-203 exerts weight-loss and lipid-lowering effects by increasing total BA excretion in obese rodents. miR-203 overexpression transgenic mice are resistant to high-fat diet (HFD)-induced obesity and dyslipidemia. Moreover, the knockdown of miR-203 deteriorates metabolic disorders. ASBT plays important role in regulating BA homeostasis and is a direct target of miR-203. In human intestinal epithelial cells, overexpression of miR-203 decreases the cellular uptake of BA by inhibiting ASBT. Furthermore, TCF7L2 is downregulated in obese mice and acts as a transcription factor of miR-203. The ASBT mRNA level was positively correlated with the body mass index (BMI) of population, while the miR-203 level was negatively associated with BMI. Taken together, these data suggest miR-203 could be a new therapeutic BA regulator for obesity and dyslipidemia.

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miR-203 is downregulated in obese rodents and overweight/obese population

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ASBT is a direct target of miR-203 in obesity

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TCF7L2 acts as an upstream activator of miR-203 in obesity

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miR-203 ameliorates obesity and dyslipidemia by increasing TBAs and lipids excretion

Sargassum fusiforme polysaccharide is a potential auxiliary substance for metformin in the management of diabetes

The present study investigated the positive effects of relatively low-dose metformin combined with Sargassum fusiforme polysaccharide (LMET-SFP) in high-fat diet and streptozotocin-induced diabetic rats, and explored the underlying mechanisms of LMET-SFP as compared to metformin alone in managing diabetes. The results indicate that both metformin and LMET-SFP can attenuate body weight loss and ameliorate hyperglycemia, insulin resistance and hyperlipidemia, and LMET-SFP exhibited better effects in lowering fasting blood glucose levels, insulin resistance index and serum cholesterol compared to metformin only. The administration of LMET-SFP could ameliorate liver dysfunction in diabetic rats. In addition, fecal bile acid data implied that LMET-SFP intervention contributed to an increase in fecal total bile acids, ursodesoxycholic acid and tauroursodesoxycholic acid profiles when compared to metformin treatment. Additionally, intestinal microbiological analysis showed that the acknowledged probiotics Lactobacillus and Bifidobacterium exhibited higher levels in the LMET-SFP group compared to the metformin group. RT-qPCR results demonstrated that the better hypoglycemic effects of LMET-SFP were mainly attributed to the down-regulation of 3-hydroxy-3-methylglutaryl-coenzyme A, cytosolic phosphoenolpyruvate carboxykinase and glucose-6-phosphatase expression, and the up-regulation of cholesterol 7α-hydroxylase expression, in contrast to metformin alone. These results suggest that SFP may be used as an auxiliary hypoglycemic substance for metformin in the future.

Protective Mechanism of Common Buckwheat (Fagopyrum esculentum Moench.) against Nonalcoholic Fatty Liver Disease Associated with Dyslipidemia in Mice Fed a High-Fat and High-Cholesterol Diet

This study aimed to investigate the protective mechanism of common buckwheat (Fagopyrum esculentum Moench.) against nonalcoholic fatty liver disease (NAFLD) associated with dyslipidemia in mice that were fed a high-fat and high-cholesterol diet (HFD). Results showed that oral supplementation of common buckwheat significantly improved physiological indexes and biochemical parameters related to dyslipidemia and NAFLD in mice fed with HFD. Furthermore, the HFD-induced reductions in fecal short-chain fatty acids were reversed by common buckwheat intervention, which also increased the fecal bile acid (BA) abundance compared with HFD-induced hyperlipidemic mice. Liver metabolomics based on ultraperformance liquid chromatography-quadrupole time-of-flight mass spectrometry demonstrated that common buckwheat supplementation made significant regulatory effects on the pentose phosphate pathway, starch and sucrose metabolism, primary BA biosynthesis, and so forth. The results of high-throughput sequencing revealed that common buckwheat supplementation significantly altered the structure of the intestinal microbiota in mice fed with HFD. The correlations between lipid metabolic parameters and intestinal microbial phylotypes were also revealed by the heatmap and network. Additionally, common buckwheat intervention regulated the mRNA expressions of genes responsible for liver lipid metabolism and BA homeostasis, thus promoting BA synthesis and excretion. These findings confirmed that common buckwheat has the outstanding ability of improving lipid metabolism and could be used as a potential functional food for the prevention of NAFLD and hyperlipidemia.

High fat diet significantly changed the global gene expression profile involved in hepatic drug metabolism and pharmacokinetic system in mice

Background

High fat diet impact transcription of hepatic genes responsible for drug metabolism and pharmacokinetics. Until now, researches just focused on a couple specific genes without a global profile showing. Age-dependent manner was also not noted well. This study aims to investigate the high fat diet effect on transcriptome of drug metabolism and pharmacokinetic system in mouse livers and show the age-dependent evidence.

Methods

C57BL/6 male mice were used in this experiment. High fat diet was used to treat mice for 16 and 38 weeks. Serum total cholesterol, low density lipoprotein cholesterol, aspartate transaminase, and alanine transaminaselevels were measured. Meanwhile, Histology, RNA-Seq, RT-PCR analysis and fourteen major hepatic bile acids quantification were performed for the liver tissues. Data was mined at levels of genes, drug metabolism and pharmacokinetic sysem, and genome wide.

Results

Treatment with high fat diet for 38 weeks significantly increased levels of serum lipids as well as aspartate transaminase, and alanine transaminase. Meanwhile, lipid accumulation in livers was observed. At week 38 of the experiment, the profile of 612 genes involved in drug metabolism and pharmacokinetics was significantly changed, indicated by a heatmap visulization and a principal component analysis. In total 210 genes were significantly regulated. Cyp3a11, Cyp4a10, and Cyp4a14 were down-regulated by 10–35 folds, while these three genes also were highly expressed in the liver. High fat diet regulated 11% of genome-wide gene while 30% of genes involved in the hepatic drug metabolism and pharmacokinetic system. Genes, including Adh4, Aldh1b1, Cyp3a11, Cyp4a10, Cyp8b1, Fmo2, Gsta3, Nat8f1, Slc22a7, Slco1a4, Sult5a1, and Ugt1a9, were regulated by high fat diet as an aging-dependent manner. Bile acids homeostasis, in which many genes related to metabolism and transportation were enriched, was also changed by high fat diet with an aging-dependet manner. Expression of genes in drug metabolism and disposition system significantly correlated to serum lipid profiles, and frequently correlated with each other.

Conclusions

High fat diet changed the global transcription profile of hepatic drug metabolism and pharmacokinetic system with a age-dependent manner.

Effect of superparamagnetic iron oxide nanoparticles on glucose homeostasis on type 2 diabetes experimental model

AIMS

Evaluation of the anti-diabetic effect of superparamagnetic iron oxide nanoparticles (SPIONs) on Type 2 diabetic rats and compared their effect to metformin treatment.

MAIN METHODS

Diabetic rats were treated with different doses of nanoparticles one time per week for 4 weeks. Fasting blood glucose level was determined for studied groups during the experimental period (30 days). At the end of the experiment, oral glucose tolerance test was carried out, serum samples were collected for biochemical assays. Then animals were sacrificed to obtain tissues for assessment of glucose transporters, insulin receptors and insulin signaling proteins.

KEY FINDING

SPIONs treatment normalized fasting blood glucose and lowering insulin level in diabetic rats compared to untreated diabetic rats. SPIONs significantly ameliorate the glucose sensing and the active components of insulin signaling pathway. The anti-diabetic effects of SPIONs may be mediated through its effect on (i) hepatic peroxisome proliferator-activated receptor gamma coactivator 1-alpha content, which induced by SPIONs treatment in a dose-dependent manner, (ii) adipocytokines as SPIONs treated diabetic rats showed significantly higher levels of adiponectin and lower retinol binding protein 4 compared to untreated diabetic rats, (iii) lipid profile as SPIONs treatment significantly corrected the lipid profile in a dose-dependent manner and to a similar extent as metformin or even better.

SIGNIFICANCE

To our knowledge, this is the first study that explores the anti-diabetic effects of SPIONs on diabetic model.

Wild Italian Prunus spinosa L. Fruit Exerts In Vitro Antimicrobial Activity and Protects Against In Vitro and In Vivo Oxidative Stress

Polyphenol-rich foods could have a pivotal function in the prevention of oxidative stress-based pathologies and antibacterial action. The purpose of this study was to investigate the in vitro antimicrobial activity, as well as the in vitro and In Vivo antioxidant capacities of wild Prunus spinosa L. fruit (PSF) from the southeast regions of Italy. The total phenolic content (TPC) was quantified, and the single polyphenols were analyzed by HPLC-DAD, showing high rutin and 4-hydroxybenzoic acid levels, followed by gallic and trans-sinapic acids. PSF extract demonstrated antimicrobial activity against some potentially pathogenic Gram-negative and Gram-positive bacteria. Besides, we investigated the cellular antioxidant activity (CAA) and the hemolysis inhibition of PSF extract on human erythrocytes, evidencing both a good antioxidant power and a marked hemolysis inhibition. Furthermore, an In Vivo experiment with oxidative stress-induced rats treated with a high-fat diet (HFD) and a low dose of streptozotocin (STZ) demonstrated that PSF has a dose-dependent antioxidant capacity both in liver and in brain. In conclusion, the wild Italian Prunus spinosa L. fruit could be considered a potentially useful material for both nutraceutical and food industries because of its antioxidant and antimicrobial effects.

A Possible Mechanism of Metformin in Improving Insulin Resistance in Diabetic Rat Models

BACKGROUND

Type 2 diabetes has become one of the most common diseases worldwide, causing a serious social burden. As a first-line treatment for diabetes, metformin can effectively improve insulin resistance. It has been reported that 12α-hydroxylated BA (mainly CA) is associated with insulin resistance. The purpose of this study was to analyze the changes in CA and possible signaling mechanisms in diabetic rats after metformin intervention.

METHODS

HepG2 cells were cultured after adding different concentrations of metformin. The cell viability was measured using CCK8 kit, and the expression of FXR, MAFG, and CYP8B1 in cells was detected by WB. The rat models of type 2 diabetes were induced by low-dose streptozotocin by feeding a high-fat diet, and the control rats (CON) were fed on normal food; the diabetic rats (DM) were given a high-fat diet without supplementation with metformin, while the metformin-treated diabetic rats (DM + MET) were given a high-fat diet and supplemented with metformin. Biochemical parameters were detected at the end of the test. Expression levels of FXR, CYP8B1, and MAFG were assessed by WB. Serum CA were measured using an enzyme-linked immunosorbent assay (ELISA).

RESULTS

In HepG2 cells, metformin dose-dependently enhanced the transcriptional activity of FXR and MAFG and inhibited the expression of CYP8B1. Metformin-treated DM rats showed improved glucose and bile acid metabolism. In addition, significantly increased FXR and MAFG and decreased CYP8B1 were observed in DM + MET rats. At the same time, the CA content of metformin-treated rats was lower than that of diabetic rats.

CONCLUSION

Changes in CA synthesis after metformin treatment may be associated with inhibition of CYP8B1. These results may play an important role in improving insulin sensitivity after metformin treatment.

Rapeseed Protein-Derived Antioxidant Peptide RAP Ameliorates Nonalcoholic Steatohepatitis and Related Metabolic Disorders in Mice

Rapeseed protein hydrolysates have recently shown in vitro antioxidant and anti-inflammatory activities. However, scant data exist about their in vivo activities. Here, we report that the peptide DHNNPQIR (hereinafter referred to as RAP-8), a bioactive peptide originated from rapeseed protein, exhibits excellent in vivo efficacy in mouse models of nonalcoholic steatohepatitis (NASH) and hepatic fibrosis. We demonstrated that RAP-8 significantly reduced hepatic steatosis and improved insulin resistance and lipid metabolism. Furthermore, RAP-8 showed markedly reduced hepatic inflammation, fibrosis, liver injury, and metabolic deterioration. In particular, RAP-8 directly suppressed fibrosis-associated gene expression, including α-smooth muscle actin (α-Sma) and collagen type I (Col-1α) in the liver of mice in vivo. In addtion, RAP-8 significantly decreased macrophage infiltration and reduced pro-inflammatory cytokines secretion. Finally, we found that RAP-8 administration significantly decreased oxidative stress-induced apoptosis in liver injury induced by CCl₄. Therefore, our results suggest that RAP-8 could be available for treatment of NASH and NASH-related metabolic disorders as a potential therapeutic candidate.

Meloxicam Improves Cognitive Impairment of Diabetic Rats through COX2-PGE2-EPs-cAMP/pPKA Pathway

Diabetics often face greater risk of cognitive impairment than nondiabetics. However, how to prevent this disease is still unconfirmed. In this study, we investigated the potential protection and mechanism of meloxicam on cognitive impairment in diabetic rats. The diabetic rat model was established with a high-fat diet and a small dose of streptozotocin (40 mg/kg). The changes of spatial learning and memory, histopathology, and the protein expressions of amyloid protein precursor (APP) and β-amyloid (Aβ) indicated that diabetic rats had neuronal injury and cognitive impairment. Tumor necrosis factor α (TNFα), interleukin 6 (IL-6), C reactive protein (CRP) and prostaglandin E2 (PGE2) levels, and microglial cell number were significantly increased in the diabetic rat brain. Meanwhile, the protein expressions of APP, Aβ, cyclooxygenases2 (COX2), E-type prostanoid recptors 1 (EP1) and EP2, and the level of cyclic adenosine monophosphate (cAMP) were significantly increased, while the protein expressions of EP3 and phosphorylated protein kinase A (pPKA) were significantly decreased in the diabetic rat hippocampus and cortex. However, the EP4 protein expression had no significant changes. Meloxicam significantly improved neuronal injury and cognitive impairment, and significantly decreased inflammatory cytokines levels. Meloxicam also significantly decreased the protein expressions of APP, Aβ, COX2, EP1 and EP2, and the level of cAMP and significantly increased the EP3 and pPKA protein expressions in rat hippocampus and cortex. However, meloxicam did not significantly influence the levels of blood glucose, lipids, and insulin of rats. Our results suggest that meloxicam could significantly protect diabetic rats from cognitive impairment via a mechanism that may be associated with rebalancing the COX2-PGE2-EPs-cAMP/PKA pathway.

Farnesoid X receptor agonist INT-767 attenuates liver steatosis and inflammation in rat model of nonalcoholic steatohepatitis

Introduction

Nonalcoholic steatohepatitis (NASH) is largely driven by the dysregulation of liver metabolism and inflammation. Bile acids and their receptor Farnesoid X receptor (FXR) play a critical role in the disease development. Here, we investigated whether INT-767, the newly-identified dual FXR/TGR5 agonist, can protect rat from liver injury during NASH.

Materials and methods

NASH model was established by feeding the male SD rats with high-fat diet for 16 weeks. INT-767 was given by gavage to NASH rats from week 13 to week 16. At the end of 16 weeks, liver and serum were harvested, and bile acids, glucose and lipid metabolism, liver injury and histological features were evaluated.

Results

INT-767 treatment significantly alleviates high-fat caused liver damage characterized with lipid accumulation and hepatic infiltration of immune cells. INT-767 robustly restores the lipid, glucose metabolism to normal level, attenuates insulin resistance through upregulating FXR level and reverting the dysregulation of its target genes in liver metabolism. Molecularly INT-767 also attenuates the pro-inflammatory response by suppression of TNF-α and NF-κB signaling pathway.

Conclusion

INT-767 may be an attractive candidate for a potential novel strategy on the treatment of NASH.

Gypenosides Altered Hepatic Bile Acids Homeostasis in Mice Treated with High Fat Diet

Gypenosides extracted from Gynostemma pentaphyllum (Thunb.) Makino have significant role in reducing serum lipid level and treating fatty liver diseases, however, without clear mechanism. As gypenosides share the similar core structures with bile acids (the endogenous ligands of nuclear receptor FXR), we hypothesize that gypenosides may improve hypercholesterolemia via FXR-mediated bile acids signaling. The present study was designed to validate the role of gypenosides in reducing levels of serum total cholesterol (TC) and low density lipoprotein cholesterol (LDL-C), as well as in regulating bile acids homeostasis and related gene expression levels. The C57BL/6 male mice were divided into four groups. Mice in groups ND and HFD were fed with normal diet and high fat diet for 38 weeks, respectively. In groups HFD+GP and HFD+ST, mice were fed with high fat diet for 38 weeks and treated with gypenosides and simvastatin (positive control) from weeks 16 to 38, respectively. Serum TC and LDL-C levels were assayed by commercially available kits. Expression levels of genes were tested by the quantitative real-time PCR. The LC-MS/MS was applied to quantify major bile acids in mice livers. Our results showed that gypenosides significantly decreased serum TC and LDL-C levels. The gene expression level of Shp was downregulated while the levels of Cyp7a1, Cyp8b1, Fxr, Lrh1, Jnk1/2, and Erk1/2 were upregulated by gypenosides. Indicated by LC-MS/MS technology, gypenosides increased the hepatic levels of several free bile acids and most taurine-conjugated bile acids while decreasing glycine-conjugated bile acids levels. In addition, gypenosides decreased the CA/CDCA ratio. Gypenosides may improve the abnormal lipid profile of HFD-fed mice via two pathways: (1) enhancing the bile acids biosynthesis from cholesterol; (2) decreasing the CA/CDCA ratio which is positively related to cholesterol absorption.

Hepatic farnesoid X receptor protein level and circulating fibroblast growth factor 19 concentration in children with NAFLD

BACKGROUND & AIMS

Treatment with the farnesoid X receptor (FXR) agonist obeticholic acid is ineffective in some patients with non-alcoholic steatohepatitis (NASH) but the explanation is uncertain. We investigated hepatic FXR expression, and measurements of fibroblast growth factor 19 (FGF19) and bile acids (BAs) in children with NAFLD to investigate relationships with NASH.

METHODS

33 children with NAFLD who underwent diagnostic liver biopsy were studied. Hepatic FXR protein levels and circulating FGF19 concentrations were compared with those analysed in five control subjects with proven normal liver histology. NASH was defined by the Paediatric NAFLD Histological Score (PNHS). Binary logistic regression with adjustment for covariates and potential confounders was undertaken to test factors independently associated with: a) NASH and b) hepatic FXR protein levels.

RESULTS

Mean ± SD age was 13.7 ± 1.9 years. Nineteen patients had NASH (PNHS ≥ 85) and 14 did not have NASH (PNHS < 85). Hepatic FXR level and plasma FGF19 concentration varied ~10-fold and 5-fold, respectively, between groups, and was highest in control subjects, intermediate in NAFLD without NASH, and lowest in NASH (between group differences P < .001 and P < .01 respectively). NASH was independently associated with both FXR protein levels (OR = 0.18, 95% CI 0.09, 0.38) and FGF19 concentration (OR = 0.55, 95% CI 0.20, 0.89).

CONCLUSIONS

FXR protein levels vary markedly between normal liver, NAFLD without NASH, and NASH. Low levels of FXR are independently associated with NASH.

Chinese Olive (Canarium album L.) Fruit Extract Attenuates Metabolic Dysfunction in Diabetic Rats

Hyperglycemia and dysregulation of lipid metabolism play a crucial role in metabolic dysfunction. The aims of present study were to evaluate the ameliorative effect of the ethyl acetate fraction of Chinese olive fruit extract (CO-EtOAc) on high-fat diet (HFD) and streptozotocin (STZ)-induced diabetic rats. CO-EtOAc, rich in gallic acid and ellagic acid, could markedly decreased the body weight and epididymal adipose mass. In addition, CO-EtOAc increased serum HDL-C levels, hepatic GSH levels, and antioxidant enzyme activities; lowered blood glucose, serum levels of total cholesterol (TC), triglycerides (TG), bile acid, and tumor necrosis factor alpha (TNFα); and reduced TC and TG in liver. We further demonstrated that CO-EtOAc mildly suppressed hepatic levels of phosphorylated IRS-1, TNF-α, and IL-6, but enhanced Akt phosphorylation. The possible mechanisms of cholesterol metabolism were assessed by determining the expression of genes involved in cholesterol transportation, biosynthesis, and degradation. It was found that CO-EtOAc not only inhibited mRNA levels of SREBP-2, HMG-CoAR, SR-B1, and CYP7A1 but also increased the expression of genes, such as ABCA1 and LDLR that governed cholesterol efflux and cholesterol uptake. Moreover, the protein expressions of ABCA1 and LDLR were also significantly increased in the liver of rats supplemented with CO-EtOAc. We suggest that Chinese olive fruit may ameliorate metabolic dysfunction in diabetic rats under HFD challenge.

Scopoletin Supplementation Ameliorates Steatosis and Inflammation in Diabetic Mice

Scopoletin is a bioactive component in many edible plants and fruits. This study investigated the effects of scopoletin on hepatic steatosis and inflammation in a high-fat diet fed type 1 diabetic mice by comparison with metformin. Scopoletin (0.01%, w/w) or metformin (0.5%, w/w) was provided with a high-fat diet to streptozotocin-induced diabetic mice for 11 weeks. Both scopoletin and metformin lowered blood glucose and HbA_1c , serum ALT, TNF-α and IL-6 levels, glucose intolerance, and hepatic lipid accumulation compared with the diabetic control group. Scopoletin or metformin down-regulated hepatic gene expression of triglyceride (Pparg, Plpp2, and Dgat2) and cholesterol (Hmgcr) synthesis as well as inflammation (Tlr4, Myd88, Nfkb1, Tnfa, and Il6), while it up-regulated Cyp7a1 gene. Hepatic PPARγ and DGAT2 protein levels were also down-regulated in scopoletin or metformin group compared with the control group. Scopoletin or metformin also inhibited hepatic fatty acid synthase and phosphatidate phosphohydrolase activities. These results suggest that scopoletin protects against diabetes-induced steatosis and inflammation by inhibiting lipid biosynthesis and TLR4-MyD88 pathways. Copyright © 2017 John Wiley & Sons, Ltd.

Exacerbation of liver steatosis following exposure to famine and overnutrition

SCOPE

People suffering from famine in early life and overnutrition in adulthood may have an increased risk for liver steatosis. We aimed to investigate the effects and mechanisms of early nutrition restriction and overnutrition on de novo lipogenesis in the liver.

METHODS AND RESULTS

Three-wk-old male rats were food restricted for 4 wk and refed a high-fat or normal fat diet individually in metabolic cages for 9 wk. Weight-matched groups were also set up. Fatty acid synthetase expression was measured to estimate de novo lipogenesis in the liver. Parameters of glucose and lipid metabolism were measured with isotope assays. All four groups had comparable body weights. However, the famine high-fat diet group had the highest degree of liver steatosis, the greatest body fat ratio, and insulin resistance. Lipid accumulation, fatty acid synthetase expression, and gluconeogenesis in the liver were significantly higher in the famine and high-fat diet groups (p < 0.05). Moreover, these groups also had markedly lower muscle glucose uptake.

CONCLUSION

Under famine and high-fat refeeding stress, rats were extremely susceptible to developing hepatic steatosis. This is presumably a consequence of upregulation of de novo lipogenesis and enhanced glucose flux from muscle to de novo lipogenesis in the liver.

Long-term obestatin treatment of mice type 2 diabetes increases insulin sensitivity and improves liver function

PURPOSE

Obestatin and ghrelin are peptides encoded by the preproghrelin gene. Obestatin inhibits food intake, in addition to regulation of glucose and lipid metabolism. Here, we test the ability of obestatin at improving metabolic control and liver function in type 2 diabetic animals (type 2 diabetes mellitus).

METHODS

The effects of chronic obestatin treatment of mice with experimentally induced type 2 diabetes mellitus on serum levels of glucose and lipids, and insulin sensitivity are characterized. In addition, alterations of hepatic lipid and glycogen contents are evaluated.

RESULTS

Obestatin reduced body weight and decreased serum glucose, fructosamine, and β-hydroxybutyrate levels, as well as total and low-density lipoprotein fractions of cholesterol. In addition, obestatin increased high-density lipoproteins cholesterol levels and enhanced insulin sensitivity in mice with type 2 diabetes mellitus. Moreover, obestatin diminished liver mass, hepatic triglycerides and cholesterol contents, while glycogen content was higher in livers of healthy and mice with type 2 diabetes mellitus treated with obestatin. These changes were accompanied by reduction of increased alanine aminotransferase, aspartate aminotransferase, and gamma glutamyl transpeptidase in T2DM mice with type 2 diabetes mellitus. Obestatin increased adiponectin levels and reduced leptin concentration. Obestatin influenced the expression of genes involved in lipid and carbohydrate metabolism by increasing Fabp5 and decreasing G6pc, Pepck, Fgf21 mRNA in the liver. Obestatin increased both, AKT and AMPK phosphorylation, and sirtuin 1 (SIRT1) protein levels as well as mRNA expression in the liver.

CONCLUSION

Obestatin improves metabolic abnormalities in type 2 diabetes mellitus, restores hepatic lipid contents and decreases hepatic enzymes. Therefore, obestatin could potentially have a therapeutic relevance in treating of insulin resistance and metabolic dysfunctions in type 2 diabetes mellitus.

The role of bile acids in nonalcoholic fatty liver disease and nonalcoholic steatohepatitis

Nonalcoholic fatty liver disease is growing in prevalence worldwide. It is marked by the presence of macrosteatosis on liver histology but is often clinically asymptomatic. However, it can progress into nonalcoholic steatohepatitis which is a more severe form of liver disease characterized by inflammation and fibrosis. Further progression leads to cirrhosis, which predisposes patients to hepatocellular carcinoma or liver failure. The mechanism by which simple steatosis progresses to steatohepatitis is not entirely clear. However, multiple pathways have been proposed. A common link amongst many of these pathways is disruption of the homeostasis of bile acids. Other than aiding in the absorption of lipids and lipid-soluble vitamins, bile acids act as ligands. For example, they bind to farnesoid X receptor, which is critically involved in many of the pathways responsible for maintaining bile acid, glucose, and lipid homeostasis. Alterations to these pathways can lead to dysregulation of energy balance and increased inflammation and fibrosis. Repeated insults over time may be the key to development of steatohepatitis. For this reason, current drug therapies target aspects of these pathways to try to reduce and halt inflammation and fibrosis. This review will focus on the role of bile acids in these various pathways and how changes in these pathways may result in steatohepatitis. While there is no approved pharmaceutical treatment for either hepatic steatosis or steatohepatitis, this review will also touch upon the multitude of potential therapies.