Mild hepatic fibrosis in cholesterol and sodium cholate diet-fed rats

Chrysin reduces heart endoplasmic reticulum stress-induced apoptosis by inhibiting PERK and Caspase 3-7 in high-fat diet-fed rats

BACKGROUND

Chrysin (Chy) is a naturally occurring flavonoid found in fruits, vegetables, honey, propolis, and many plant extracts that has shown notable medicinal value. Chy exhibits diverse pharmacological properties, including anti-oxidative, anti-inflammatory, anti-apoptotic, anti-cholesteremic, and cardioprotective. However, the influence of Chy in mitigating high-fat diet (HFD)-induced ER stress of rat myocardium remains unknown.

PURPOSE

The current work intended to determine the therapeutic potential of Chy against HFD-induced endoplasmic stress-mediated apoptosis.

METHODS

To evaluate the therapeutic value of Chy in HFD-induced endoplasmic stress-mediated apoptosis in the myocardium; The male wistar rats were divided into different groups; control, HFD control, HFD fed followed by Chy-treated and HFD fed followed by atorvastatin (Atv) treated rats.

RESULTS

When compared to the control group, the HFD-fed rats had significantly higher levels of marker enzymes such as CK-NAC and ALP, as well as lipid peroxidation and lipid profile (TC, TG, LDL, and VLDL). Chy therapy greatly reversed these marker enzymes and the lipid profile. qRT-PCR Studies showed that Chy supplementation considerably improved Nrf2 and its target genes. In addition, Chy lowered the expression of PERK, CHOP, ATF6, GRP78, and Caspase-3 genes in the heart tissue of HFD-fed rats. Immunohistochemistry results demonstrated that Chy substantially enhanced the Nrf2 and reduced PERK and Caspase3-7 protein expression in HFD-fed rats.

CONCLUSION

The current study concluded that Chy may mediate the cardioprotective effect by activating Nrf2 and inhibiting PERK signaling pathway against ER stress-mediated apoptosis induced by HFD. Therefore, supplementation with Chy could serve as a promising therapeutic target against HFD-induced ER stress-mediated cardiac complication.

An overview of the cholesterol metabolism and its proinflammatory role in the development of MASLD

Cholesterol is an essential lipid molecule in mammalian cells. It is not only involved in the formation of cell membranes but also serves as a raw material for the synthesis of bile acids, vitamin D, and steroid hormones. Additionally, it acts as a covalent modifier of proteins and plays a crucial role in numerous life processes. Generally, the metabolic processes of cholesterol absorption, synthesis, conversion, and efflux are strictly regulated. Excessive accumulation of cholesterol in the body is a risk factor for metabolic diseases such as cardiovascular disease, type 2 diabetes, and metabolic dysfunction-associated steatotic liver disease (MASLD). In this review, we first provide an overview of the discovery of cholesterol and the fundamental process of cholesterol metabolism. We then summarize the relationship between dietary cholesterol intake and the risk of developing MASLD, and also the animal models of MASLD specifically established with a cholesterol-containing diet. In the end, the role of cholesterol-induced inflammation in the initiation and development of MASLD is discussed.

L-carnitine and Ginkgo biloba Supplementation In Vivo Ameliorates HCD-Induced Steatohepatitis and Dyslipidemia by Regulating Hepatic Metabolism

Treatment strategies for steatohepatitis are of special interest given the high prevalence of obesity and fatty liver disease worldwide. This study aimed to investigate the potential therapeutic mechanism of L-carnitine (LC) and Ginkgo biloba leaf extract (GB) supplementation in ameliorating the adverse effects of hyperlipidemia and hepatosteatosis induced by a high-cholesterol diet (HCD) in an animal model. The study involved 50 rats divided into five groups, including a control group, a group receiving only an HCD, and three groups receiving an HCD along with either LC (300 mg LC/kg bw), GB (100 mg GB/kg bw), or both. After eight weeks, various parameters related to lipid and glucose metabolism, antioxidant capacity, histopathology, immune reactivity, and liver ultrastructure were measured. LC + GB supplementation reduced serum total cholesterol, triglyceride, low-density lipoprotein cholesterol, glucose, insulin, HOMA-IR, alanine transaminase, and aspartate transaminase levels and increased high-density lipoprotein cholesterol levels compared with those in the HCD group. Additionally, treatment with both supplements improved antioxidant ability and reduced lipid peroxidation. The histological examination confirmed that the combination therapy reduced liver steatosis and fibrosis while also improving the appearance of cell organelles in the ultrastructural hepatocytes. Finally, the immunohistochemical analysis indicated that cotreatment with LC + GB upregulated the immune expression of GLP-1 and β-Cat in liver sections that were similar to those of the control animals. Mono-treatment with LC or GB alone substantially but not completely protected the liver tissue, while the combined use of LC and GB may be more effective in treating liver damage caused by high cholesterol than either supplement alone by regulating hepatic oxidative stress and the protein expression of GLP-1 and β-Cat.

Chrysin reduces hypercholesterolemia-mediated atherosclerosis through modulating oxidative stress, microflora, and apoptosis in experimental rats

Chrysin (Chy) is known for various biological proprieties such as inhibitory effects on inflammation, cancer, oxidative stress, aging, and atherosclerosis. However, the hypolipidemic activity of Chy and its mechanistic action remains unclear in cardiovascular diseases (CVD). In this study, we focused on the hypolipidemic proprieties of Chy in hypercholesterolemia-induced atherosclerosis. Male Wistar rats (150-220 g) were divided into four groups as follows: Group I control was fed with standard laboratory chow. Rats in Group II were fed a high-fat diet (HFD) for 60 days. After 60 days of HFD, Group III rats received Chy (100 mg/kg body weight); Group IV rats received Atorvastatin (Atv; 10 mg/kg body weight) for 30 days. Biochemical studies showed Chy, Atv treatment decreased the activities of liver marker enzymes and the levels of Reactive Oxygen Species (ROS) and lipid profile. Gene expression analysis on nuclear factor erythroid 2-related factor 2 (Nrf2) and its regulated genes were significantly reduced in the intestine and increased in the aorta by Chy and Atv. Gut microbial species such as Bacteroidetes, Lactobacillus, Enterococcus, and Clostridium leptum copy numbers were significantly increased by Chy and Atv treatment. In addition, Chy and Atv modulated the expression of inflammatory genes including TLR4, TNFα, NLRP3, and IL-17 in the aorta and intestine compared with hypercholesterolemic control rats. Chy and Atv effectively increased the caspase-3 mRNA expression in the intestine, but these decreased in the aorta. The present study concludes that by reducing oxidative stress and increasing gut microbial colonization, Chy may provide an effective therapeutic approach for the prevention of hypercholesterolemia-mediated atherosclerosis. PRACTICAL APPLICATIONS: Our study focused on a therapeutic model representing the clinical presentation of atherosclerosis in humans. Statins are commonly used in the treatment of cardiovascular complications, patients with hypercholesterolemia face difficulties in the continuation of statin therapy. The reason for statin discontinuation has been associated with toxicological effects. It is necessary to investigate the potentiality of the natural compound as an alternative medicine to statin with fewer side effects. The main theme of our study is to compare the therapeutic potential of Chy and Atv. Chy is a natural bioflavonoid that could be considered as an alternative medicinal compound to statins and to avoid toxicity problems associated with statins. Chy is a bioflavonoid present in Passiflora caerulea (blue passion flower), Oroxylum indicum (Indian trumpet flower), Pelargonium crispum, propolis, and honey. Consuming Chy-rich foods will reduce hypercholesterolemia-mediated cardiovascular complications. Overall, the present studies provided a key to developing bioactive compounds-based foods for CVD patients.

Acanthaster planci Inhibits PCSK9 and Lowers Cholesterol Levels in Rats

Atherosclerosis is the main cause of cardiovascular diseases which in turn, lead to the highest number of mortalities globally. This pathophysiological condition is developed due to a constant elevated level of plasma cholesterols. Statin is currently the widely used treatment in reducing the level of cholesterols, however, it may cause adverse side effects. Therefore, there is an urgent need to search for new alternative treatment. PCSK9 is an enzyme responsible in directing LDL-receptor (LDL-R)/LDL-cholesterols (LDL-C) complex to lysosomal degradation, preventing the receptor from recycling back to the surface of liver cells. Therefore, PCSK9 offers a potential target to search for small molecule inhibitors which inhibit the function of this enzyme. In this study, a marine invertebrate Acanthaster planci, was used to investigate its potential in inhibiting PCSK9 and lowering the levels of cholesterols. Cytotoxicity activity of A. planci on human liver HepG2 cells was carried out using the MTS assay. It was found that methanolic extract and fractions did not exhibit cytotoxicity effect on HepG2 cell line with IC50 values of more than 30 µg/mL. A compound deoxythymidine also did not exert any cytotoxicity activity with IC50 value of more than 4 µg/mL. Transient transfection and luciferase assay were conducted to determine the effects of A. planci on the transcriptional activity of PCSK9 promoter. Methanolic extract and Fraction 2 (EF2) produced the lowest reduction in PCSK9 promoter activity to 70 and 20% of control at 12.5 and 6.25 μg/mL, respectively. In addition, deoxythymidine also decreased PCSK9 promoter activity to the lowest level of 60% control at 3.13 μM. An in vivo study using Sprague Dawley rats demonstrated that 50 and 100 mg/kg of A. planci methanolic extract reduced the total cholesterols and LDL-C levels to almost similar levels of untreated controls. The level of serum glutamate oxalate transaminase (SGOT) and serum glutamate pyruvate transaminase (SGPT) showed that the administration of the extract did not produce any toxicity effect and cause any damage to rat liver. The results strongly indicate that A. planci produced a significant inhibitory activity on PCSK9 gene expression in HepG2 cells which may be responsible for inducing the uptake of cholesterols by liver, thus, reducing the circulating levels of total cholesterols and LDL-C. Interestingly, A. planci also did show any adverse hepato-cytotoxicity and toxic effects on liver. Thus, this study strongly suggests that A. planci has a vast potential to be further developed as a new class of therapeutic agent in lowering the blood cholesterols and reducing the progression of atherosclerosis.

Chrysin attenuates high-fat-diet-induced myocardial oxidative stress via upregulating eNOS and Nrf2 target genes in rats

Hypercholesterolemia is one of the risk factors associated with increased morbidity and mortality in cardiovascular disorders. Chrysin (Chy) is reported to exhibit anti-inflammatory, anti-cancerous, anti-oxidative, anti-aging, and anti-atherogenic properties. In the present study, we aimed to investigate whether Chy would mediate the cardioprotective effect against hypercholesterolemia-triggered myocardial oxidative stress. Male Sprague Dawley rats were divided into different groups as control and fed with high-fat diet (HFD) followed by oral administration of Chy (100 mg/kg b.wt), atorvastatin (Atv) (10 mg/kg b.wt), and L-NAME (10 mg/kg b.wt) for 30 days. At the end of the experimental period, the rats were sacrificed and tissues were harvested. Biochemical results showed a significant increase of cardiac disease marker enzymes (ALT, AST, and CKMB), lipid peroxidation, and lipid profile (TC, TG, LDL, and VLDL) in HFD-fed rat tissues when compared to control, whereas oral administration of Chy significantly reduced the activities of these marker enzymes and controlled the lipid profile. qRT-PCR studies revealed that Chy administration significantly increased the expression of endothelial nitric oxide synthase (eNOS), and Nrf2 target genes such as SOD, catalase, and GCL3 in left ventricular heart tissue of HFD-challenged rats. Immunohistochemistry results also showed that Chy treatment increased myocardial protein expression of eNOS and Nrf2 in HFD-challenged rats. Concluding the results of the present study, the Chy could mediate the cardioprotective effect through the activation of eNOS and Nrf2 signaling against hypercholesterolemia-induced oxidative stress. Thus, the administration of Chy would provide a promising therapeutic strategy for the prevention of HFD-induced oxidative stress-mediated myocardial complications.

Pathophysiology of NAFLD and NASH in Experimental Models: The Role of Food Intake Regulating Peptides

Obesity, diabetes, insulin resistance, sedentary lifestyle, and Western diet are the key factors underlying non-alcoholic fatty liver disease (NAFLD), one of the most common liver diseases in developed countries. In many cases, NAFLD further progresses to non-alcoholic steatohepatitis (NASH), fibrosis, cirrhosis, and to hepatocellular carcinoma. The hepatic lipotoxicity and non-liver factors, such as adipose tissue inflammation and gastrointestinal imbalances were linked to evolution of NAFLD. Nowadays, the degree of adipose tissue inflammation was shown to directly correlate with the severity of NAFLD. Consumption of higher caloric intake is increasingly emerging as a fuel of metabolic inflammation not only in obesity-related disorders but also NAFLD. However, multiple causes of NAFLD are the reason why the mechanisms of NAFLD progression to NASH are still not well understood. In this review, we explore the role of food intake regulating peptides in NAFLD and NASH mouse models. Leptin, an anorexigenic peptide, is involved in hepatic metabolism, and has an effect on NAFLD experimental models. Glucagon-like peptide-1 (GLP-1), another anorexigenic peptide, and GLP-1 receptor agonists (GLP-1R), represent potential therapeutic agents to prevent NAFLD progression to NASH. On the other hand, the deletion of ghrelin, an orexigenic peptide, prevents age-associated hepatic steatosis in mice. Because of the increasing incidence of NAFLD and NASH worldwide, the selection of appropriate animal models is important to clarify aspects of pathogenesis and progression in this field.

Inhibitory effects of tangeretin and trans-ethyl caffeate on the HMG-CoA reductase activity: Potential agents for reducing cholesterol levels

One of the pathways to reduce cholesterol production in the liver is through the inhibition of HMG-Coa reductase (HMGCR) by current drugs, statins. However, these have side effects if consumed in prolonged periods. Tangeretin and trans-ethyl caffeate as alternative drugs in reducing hypercholesterolemia and preventing atherosclerosis have never been reported. Their effects on inhibiting HMGCR activity were investigated through enzymatic method (in vitro and in vivo). The toxicity property was analyzed on the Serum Glutamate Oxalate Transaminase (SGOT)/Serum Glutamate Piruvate Transaminase (SGPT) levels and rat liver histology. The results showed that both compounds inhibited HMGCR activity significantly compare to the control simvastatin (p < 0.05). Tangeretin which showed very good activity in inhibiting HMGCR (83.8 of % inhibition, equal to simvastatin) was selected and used for anti-hypercholesterolemia in vivo assessment. Furthermore, tangeretin was shown to effectively reduced Total Cholesterol (TC) and Low Density Lipoprotein (LDL), and increased High Density Lipoprotein (HDL) levels significantly compared to the simvastatin group (p < 0.05). Tangeretin group was also proven to inhibit HMGCR rat liver activity significantly compare to the control simvastatin (p < 0.05). The toxicity study on the SGOT/SGPT levels and liver histology revealed that there were no side effects after administration by tangeretin. Results found that both tangeretin and trans-ethyl caffeate are potent candidates as anti-hypercholesterolemia agent in vitro. In addition, tangeretin was also shown to be safe and suitable as an alternative treatment for controlling hypercholesterolemia in vivo as well as have potency for preventing atherosclerosis.

Vitis vinifera polyphenols from seedless black fruit act synergistically to suppress hepatotoxicity by targeting necroptosis and pro-fibrotic mediators

Human is subjected from his surrounding to various hepatotoxins, which aggravates his liver. Nowadays, natural polyphenols have attracted great interest in health improvement, especially liver health. The present research, therefore, assessed the hepatotherapeutic potency of the isolated polyphenols (VVF1) from seedless (pulp and skin) black Vitis vinifera (VV) against CCl4-induced hepatotoxicity in vitro and in vivo. Further, VVF1 was fractionated into resveratrol-enriched (VVF2) and phenolics-enriched (VVF3) fractions to study (in vitro) the possible synergism of their coexistence. The highest content of phenolics in VVF1 displayed in vitro synergistic antioxidant and anti-hepatotoxic activities comparing to VVF2, VVF3, and silymarin (SM, reference drug). More importantly, it exhibited multiple in vivo regulatory functions via diminishing oxidative stress and inflammation, which in turn decreased necroptosis and pro-fibrotic mediators (mixed lineage kinase domain-like protein (MLKL), collagen type I alpha 1 chain (COL1A1), and transforming growth factor (TGF)-β1). In addition to these novel findings, VVF1 had higher anti-hepatotoxic potency than that of SM in most of the studied parameters. The histopathological analysis confirmed the improving role of VVF1 in the serious hepatic damage induced by CCl4. Thus, the synergistic functions of VVF1 polyphenols could be a promising new anti-hepatotoxic agent for targeting both necroptotic and profibrotic mediators.

Antihypercholesterolemic and antiatherosclerotic potencies of Pandanus tectorius fruits via increasing scavenger receptor-B1 genes expression and inhibition of 3-hydroxy-3-methylglutaryl coenzyme A reductase activity

Atherosclerosis is a leading cause of death worldwide. The adverse side effects of currently available drugs urge to find more effective and safe remedial agents. Alternative candidates from natural resources are of great consequence in the emerging of new drugs. Pandanus tectorius (Pandanaceae) was traditionally used in Ayurvedic medicine to cure certain diseases. Thus, the current study conducted to elucidate the potency of P. tectorius fruit as antiatherosclerosis and antihypercholesterolemia agents through the regulation of high density lipoprotein (HDL) receptor (scavenger receptor [SR]-B1) gene expression and 3-hydroxy-3-methylglutaryl coenzyme A reductase reductase (HMGCR) in vitro, respectively. The P. tectorius fruit was noncytotoxic against the HepG2 cell line confirmed by 3-(4,5-dimethylthiazol-2-yl) 2,5-diphenyl tetrazolium bromide assay. The P. tectorius fruit successfully upregulates the SR-B1 gene expression and downregulate the HMGCR. Moreover, an in vivo study showed that P. tectorius has good activity on the upregulation of HDL and subsequently downregulation of total cholesterol level. Moreover, P. tectorius fruit did not show any increase in toxicity biomarkers serum glutamic oxaloacetic transaminase and serum glutamate pyruvate transaminase in vivo. These results found that P. tectorius fruits have potency as the preventive agent for hypercholesterolemia and atherosclerosis via SR-B1 and HMGCR mechanisms of action.

Fiber and phenolic compounds contribution to the hepatoprotective effects of mango diets in rats fed high cholesterol/sodium cholate

The present study evaluated the contribution of mango fiber (MF) and mango phenolic compounds (MP) to the hepatoprotective effect of freeze-dried mango pulp (FDM) cultivar (cv.) "Ataulfo" diets in high cholesterol/sodium cholate (HCC)-fed rats. Male Wistar rats were fed with a HCC diet for 12 weeks, either untreated, or supplemented with MF, MP, FDM, or a control diet (no HCC; n = 6/group). All mango treatments significantly decreased hepatic cholesterol deposition and altered its fatty acid profile, whereas MF and MP mitigated adipose tissue hypertrophy. MF caused a lower level of proinflammatory cytokines (IL-1α/β, IFN-γ, TNF-α) whereas FDM increased the anti-inflammatory ones (IL-4, 6, 10). Mango treatments increased catalase (CAT) activity and its mRNA expression; superoxide dismutase (SOD) activity was normalized by MF and FDM, but its activity was unrelated to its hepatic mRNA expression. Changes in CAT and SOD mRNA expression were unrelated to altered Nrf2 mRNA expression. Higher hepatic PPARα and LXRα mRNA levels were found in MP and MF. We concluded that MF and MP are highly bioactive, according to the documented hepatoprotection in HCC-fed rats; their mechanism of action appears to be related to modulating cholesterol and fatty acid metabolism as well as to stimulating the endogenous antioxidant system.

Mango phenolics increase the serum apolipoprotein A1/B ratio in rats fed high cholesterol and sodium cholate diets

BACKGROUND

Serum lipoproteins are in dynamic equilibrium, partially controlled by the apolipoprotein A1 to apolipoprotein B ratio (APOA1/APOB). Freeze-dried mango pulp (FDM) is a rich source of phenolic compounds (MP) and dietary fiber (MF), although their effects on lipoprotein metabolism have not yet been studied.

RESULTS

Thirty male Wistar rats were fed with four different isocaloric diets (3.4 kcal g^-1 ) for 12 weeks: control diet, high cholesterol (8 g kg^-1 ) + sodium cholate (2 g kg^-1 ) diet either alone or supplemented with MF (60 g kg^-1 ), MP (1 g kg^-1 ) or FDM (50 g kg^-1 ). MP and FDM reduced food intake, whereas MF and MP tended to increase serum APOA1/APOB ratio, independently of their hepatic gene expression. This suggests that lipoprotein metabolism was favorably altered by mango bioactives, MP also mitigated the non-alcoholic steatohepatitis that resulted from the intake of this diet.

CONCLUSION

We propose that phenolics are the most bioactive components of mango pulp, acting as anti-atherogenic and hepatoprotective agents, with a mechanism of action tentatively based on changes to the main protein components of lipoproteins. © 2018 Society of Chemical Industry.

l-Carnitine-induced amelioration of HFD-induced hepatic dysfunction is accompanied by a reduction in hepatic TNF-α and TGF-β1

In this study, we evaluated the possible mechanisms through which l-carnitine ameliorates the adverse effects from obesity in rats, induced with a high-fat diet (HFD). For this, 56 albino Wister rats were randomly assigned to 7 groups. The control group was fed a basal diet and injected with saline. The second group was fed the basal diet and injected with l-carnitine (200 mg/kg body mass, by intraperitoneal injection; i.p.). The third group were fed the HFD. The fourth group was fed the HFD and injected with l-carnitine (200 mg/kg body mass, i.p.) for 8 weeks. The fifth group was fed the HFD for 10 weeks. The sixth group were fed the HFD for 10 weeks and were also injected with l-carnitine (200 mg/kg body mass, i.p.) during the final 2 weeks. The seventh group was fed the HFD diet for 8 weeks then the basal diet for 2 weeks. The HFD induced significantly increased levels of hyperglycemia, lipid peroxidation, pathological changes, TNF-α and TGF-β1 protein expression in hepatic tissue, food intake, body weight gain, serum levels of total and non-high-density lipoprotein cholesterol, ketone bodies, triacylglycerol, urea, creatinine, AST, and ALT. However, the HFD diet significantly decreased serum levels of high-density lipoprotein (HDL) and hepatic levels of reduced glutathione. l-Carnitine ameliorated the effects of the HFD on the above-mentioned parameters. This study indicated that l-carnitine had protective and curative effects against HFD-induced hepatosteatosis by reducing hepatic oxidative stress and protein expression of TNF-α and TGF-β1.

Serum levels of immunoglobulins in an adult population and their relationship with nonalcoholic fatty liver disease

OBJECTIVES

Few studies have reported the association between nonalcoholic fatty liver disease (NAFLD) and immunoglobulins. In this study, we aimed to investigate the relationship between serum immunoglobulin levels and NAFLD in a Chinese adult population.

METHODS

We performed a cross-sectional study including 11 261 Chinese adults. NAFLD was diagnosed based on the Chinese Guidelines for the diagnosis and treatment of fatty liver diseases and an alcohol intake of <70 g/week in women and <140 g/week in men, and serum immunoglobulin (Ig) levels were determined using immune nephelometry. Multiple logistic regression analysis was done to assess relationships between concentrations of serum immunoglobulins and NAFLD.

RESULTS

Of the 11 261 adults recruited from January 2010 to December 2015, the prevalence of NAFLD was 40.8% (n = 4598). The geometric mean levels of IgG, IgM, IgE and IgA were 1177.49 mg/dL (95% confidence interval [CI] 1173.07-1181.93), 93.56 mg/dL (95% CI 92.70-94.42), 30.70 IU/mL (95% CI 29.92-31.49) and 216.64 mg/dL (95% CI 214.95-218.34), respectively. Compared with the lowest quintile, the multivariable adjusted odds ratio (95% CI) of NAFLD for the highest quintile of IgG, IgM, IgE, and IgA were 0.78 (0.66-0.92), 0.71 (0.60-0.84), 0.98 (0.84-1.15) and 1.41 (1.21-1.66), respectively.

CONCLUSION

Increased IgA and decreased IgG and IgM levels are independently associated with NAFLD prevalence. Further research is needed to explore the causal association between serum immunoglobulins and NAFLD.

Atorvastatin-loaded nanostructured lipid carriers (NLCs): strategy to overcome oral delivery drawbacks

Atorvastatin (AT) is a widely used lipid-regulating drug to reduce cholesterol and triglycerides. Its poor aqueous solubility and hepatic metabolism require development of drug delivery systems able to improve its solubility and bypass hepatic effect. For this purpose, atorvastatin nanostructured lipid carriers (AT-NLCs) were prepared and characterized. AT-NLCs were prepared by emulsification using high-speed homogenization followed by ultrasonication. The prepared NLCs showed particle size between 162.5 ± 12 and 865.55 ± 28 nm while zeta potential values varied between −34 ± 0.29 and −23 ± 0.36 mV. They also showed high encapsulation efficiency (>87%) and amorphous state of the drug in lipid matrix. Pharmacokinetic parameters of optimized formulation (NLC-1; composed of 2% Gelucire^® 43/01, 8% Capryol^® PGMC, 2% Pluronic^®F68 and 0.5% lecithin) revealed 3.6- and 2.1-fold increase in bioavailability as compared to atorvastatin suspension and commercial product (Lipitor^®), respectively. Administration of NLC-1 led to significant reduction (p < .05) in the rats’ serum levels of total cholesterol (TC), triglyceride (TG), low-density lipoprotein (LDL) and significant increase in high-density lipoprotein (HDL). This improvement was confirmed histologically by minimizing the associated hepatic steatosis. These investigations demonstrated the superiority of NLCs for improvement of oral bioavailability and in vivo performance of AT.

Reconstitutable spray dried ultra-fine dispersion as a robust platform for effective oral delivery of an antihyperlipidemic drug

The current article highlights the application of spray drying technique to produce an ultra-fine powder encapsulating the antihyperlipidemic drug, atorvastatin calcium (ATV). First, ATV was dissolved in an emulsion formulation, and different carriers (pectin, alginate, chitosan HCl and hydroxypropylmethyl cellulose) in two concentrations (1.5 and 3%) were added. Then, these carrier-containing formulations were subjected to spray drying, whereby ultra-fine ATV-loaded spray dried emulsions were produced (ATV-SDE). The optimum formulation; ATV-SDE7 containing 3% w/w pectin was selected showing an obviously enhanced dissolution profile compared to the other used polymers which could be attributed to its lower ability to swell in acidic medium, resulting in faster drug diffusion into release medium. Thus, ATV-SDE7 was subjected to further characterization including; DSC, XRPD, SEM and flowability properties. In-vivo studies were conducted using high-fat induced hyperlipidemic rats. The optimum formulation depicted normal lipid profile showing significant reduction in the measured parameters at the end of daily oral treatment, compared to ATV marketed tablets and control hyperlipidemic rats confirmed by normal liver sections upon histopathological examination. The superior lipid-lowering activity of ATV-SDE7 was not only due to the enhanced dissolution of ATV but also due to the presence of pectin which is capable of lowering both cholesterol and triglyceride serum levels. Hence, the present study suggests that the formulation strategy employing ultrafine redispersible spray dried emulsion with pectin as a carrier holds a promising approach for the development of a novel dosage form of enhanced antihyperlipidemic effect for ATV.

Isolated hypercholesterolemia leads to steatosis in the liver without affecting the pancreas

Background

Lipid accumulation in the liver and pancreas is primarily caused by combined hyperlipidemia. However, the effect of isolated hypercholesterolemia without hypertriglyceridemia is not fully described. Therefore, our aim was to investigate whether hypercholesterolemia alone leads to alterations both in hepatic and pancreatic lipid panel and histology in rats.

Methods

Male Wistar rats were fed with 2% cholesterol +0.25% cholate-supplemented diet or standard chow for 12 weeks. Blood was collected at weeks 0, 4, 8 and 12 to measure serum cholesterol and triglyceride levels. At week 12, both the pancreas and the liver were isolated for further histological and biochemical analysis. Hepatic and plasma fatty acid composition was assessed by gas chromatography. Expression of mRNA of major enzymes involved in saturated/unsaturated fatty acid synthesis was analyzed by qPCR. In separate experiments serum enzyme activities and insulin levels were measured at week 9.

Results

At week 12, rats fed with 2% cholesterol +0.25% cholate-supplemented diet were characterized by elevated serum cholesterol (4.09 ± 0.20 vs. 2.89 ± 0.22 mmol/L, *p < 0.05) while triglyceride (2.27 ± 0.05 vs. 2.03 ± 0.03 mmol/L) and glucose levels (5.32 ± 0.14 vs. 5.23 ± 0.10 mmol/L) remained unchanged. Isolated hypercholesterolemia increased hepatic lipid accumulation, hepatic cholesterol (5.86 ± 0.22 vs. 1.60 ± 0.15 ng/g tissue, *p < 0.05) and triglyceride contents (19.28 ± 1.42 vs. 6.78 ± 0.71 ng/g tissue, *p < 0.05), and hepatic nitrotyrosine level (4.07 ± 0.52 vs. 2.59 ± 0.31 ng/mg protein, *p < 0.05). The histology and tissue lipid content of the pancreas was not affected. Serum total protein level, alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activities remained unchanged in response to isolated hypercholesterolemia while serum alkaline phosphatase activity (ALP) significantly increased. Plasma insulin levels did not change in response to isolated hypercholesterolemia suggesting an intact endocrine function of the pancreas. Isolated hypercholesterolemia caused a significantly increased hepatic and serum fatty acid level associated with a marked alteration of fatty acid composition. Hepatic expression of Δ9-desaturase (SCD1) was increased 4.92×, while expression of Δ5-desaturase and Δ6-desaturase were decreased (0.447× and 0.577×, respectively) due to isolated hypercholesterolemia.

Conclusions

Isolated hypercholesterolemia leads to hepatic steatosis and marked alterations in the hepatic lipid profile without affecting the pancreas. Altered fatty acid profile might mediate harmful effects of cholesterol in the liver.

Metabolomic characteristics of cholesterol-induced non-obese nonalcoholic fatty liver disease in mice

Nonalcoholic fatty liver disease (NAFLD) in non-obese patients remains a clinical condition with unclear etiology and pathogenesis. Using a metabolomics approach in a mouse model that recapitulates almost all the characteristic features of non-obese NAFLD, we aimed to advance mechanistic understanding of this disorder. Mice fed high fat, high cholesterol, cholate (HFHCC) diet for three weeks consistently developed hepatic pathology similar to NAFLD and nonalcoholic steatohepatitis (NASH) without changes to body weight or fat pad weights. Gas- and liquid chromatography/mass spectrometry-based profiling of lipidomic and primary metabolism changes in the liver and plasma revealed that systemic mechanisms leading to steatosis and hepatitis in this non-obese NAFLD model were driven by a combination of effects directed by elevated free cholesterol, cholesterol esters and cholic acid, and associated changes to metabolism of sphingomyelins and phosphatidylcholines. These results demonstrate that mechanisms underlying cholesterol-induced non-obese NAFLD are distinct from NAFLD occurring as a consequence of metabolic syndrome. In addition, this investigation provides one of the first metabolite reference profiles for interpreting effects of dietary and hepatic cholesterol in human non-obese NAFLD/NASH patients.

Role of dietary onion in modifying the faecal bile acid content in rats fed a high-cholesterol diet

The determination of faecal bile patterns offers new opportunities in the search for non-invasive biomarkers of disease status. The objective of this study was to describe the shifts in faecal bile acid (BA) composition induced by feeding a high-cholesterol/cholic acid diet (HC) over 7 weeks of experimental feeding in Wistar rats, and to evaluate the effect of onion included as a functional ingredient (HCO). A HPLC-MS/MS method allowed the detection of 29 bile acids, 10 of which were tentatively identified and 12 confirmed and quantified by means of standards and calibration curves. The excretion of bile acids revealed a discriminating bile acid profile between the HC and HCO groups compared with the C group. HCO feeding indicated significant changes in specific primary and secondary BA in both the unconjugated and conjugated forms caused by the addition of the onion ingredient to the diet. The results suggest that the induction of microbiome modifications by the HC and HCO diets acts as a critical modifier of the faecal bile acid composition. These modifications might reflect and be linked to changes in the reabsorption of BA at an intestinal level and the process of BA deconjugation in the course of hypercholesterolemia.

Altered hepatic lipid metabolism in mice lacking both the melanocortin type 4 receptor and low density lipoprotein receptor

Obesity is often associated with dyslipidemia and hepatosteatosis. A number of animal models of non-alcoholic fatty liver disease (NAFLD) are established but they significantly differ in the molecular and biochemical changes depending on the genetic modification and diet used. Mice deficient for melanocortin type 4 receptor (Mc4r^mut) develop hyperphagia, obesity, and subsequently NAFLD already under regular chow and resemble more closely the energy supply-driven obesity found in humans. This animal model was used to assess the molecular and biochemical consequences of hyperphagia-induced obesity on hepatic lipid metabolism. We analyzed transcriptome changes in Mc4r^mut mice by RNA sequencing and used high resolution ¹H magic angle spinning NMR spectroscopy and MALDI-TOF mass spectrometry to assess changes in the lipid composition. On the transcriptomic level we found significant changes in components of the triacylglycerol metabolism, unsaturated fatty acids biosynthesis, peroxisome proliferator-activated receptor signaling pathways, and lipid transport and storage compared to the wild-type. These findings were supported by increases in triacylglycerol, monounsaturated fatty acid, and arachidonic acid levels. The transcriptome signatures significantly differ from those of other NAFLD mouse models supporting the concept of hepatic subphenotypes depending on the genetic background and diet. Comparative analyses of our data with previous studies allowed for the identification of common changes and genotype-specific components and pathways involved in obesity-associated NAFLD.

A diet-induced Sprague-Dawley rat model of nonalcoholic steatohepatitis-related cirrhosis

Certain modified diets containing saturated fatty acids, cholesterol or fructose lead to the development of nonalcoholic steatohepatitis (NASH)-related fibrosis in rodents; however, progression to cirrhosis is rare. Experimental liver cirrhosis models have relied on genetic manipulation or administration of hepatotoxins. This study aimed to establish a reliable dietary model of NASH-related cirrhosis in a relatively short period. Male Sprague-Dawley rats (9 weeks of age) were randomly assigned to normal, high-fat (HF), or two types (1.25% or 2.5% cholesterol) of high-fat and high-cholesterol (HFC) diets for 18 weeks. All HFC diets contained 2% cholic acid by weight. Histopathological analysis revealed that the HFC diets induced obvious hepatic steatosis, inflammation with hepatocyte ballooning and advanced fibrosis (stage 3-4) in all 12 rats at 27 weeks of age. In contrast, all five rats given the HF diet developed mild steatosis and inflammation without fibrosis. The amount of cholesterol in the liver and hepatocellular mitochondrial and microsomal fractions was significantly higher in rats fed the HFC diets than the normal or HF diets. The HFC diets significantly suppressed mRNA levels of microsomal triglyceride transfer protein, adenosine triphosphate binding cassette transporter G5, bile acid CoA: amino acid N-acyltransferase and bile salt export pump, as well as the enzymatic activity of carnitine palmitoyltransferase in the liver. In conclusion, the HFC diets induced liver cirrhosis in conjunction with hepatic features of NASH in Sprague-Dawley rats within 18 weeks, and altered gene expression and enzyme activity to accumulate lipid and bile acid in the liver.

Evaluation of Methionine Content in a High-Fat and Choline-Deficient Diet on Body Weight Gain and the Development of Non-Alcoholic Steatohepatitis in Mice

Aim

Non-alcoholic steatohepatitis (NASH) is a globally recognized liver disease. A methionine- and choline-deficient diet is used to induce NASH in mice; however, this diet also causes severe body weight loss. To resolve this issue, we examined the effects of methionine content in a high-fat and choline-deficient (HFCD) diet on body weight and the development of NASH in mice.

Methods

C57BL/6J mice (male, 10 weeks of age) were fed an L-amino acid rodent (control) diet, high-fat (HF) diet, or HFCD diet containing various amounts of methionine (0.1–0.6% (w/w)) for 12 weeks. Plasma lipid levels, hepatic lipid content and inflammatory marker gene expression were measured, and a pathological analysis was conducted to evaluate NASH.

Results

The 0.1% methionine in HFCD diet suppressed body weight gain, which was lower than that with control diet. On the other hand, the 0.2% methionine in HFCD diet yielded similar body weight gains as the control diet, while more than 0.4% methionine showed the same body weight gains as the HF diet. Liver weights and hepatic lipid contents were the greatest with 0.1% methionine and decreased in a methionine dose-dependent manner. Pathological analysis, NAFLD activity scores and gene expression levels in the liver revealed that 0.1% and 0.2% methionine for 12 weeks induced NASH, whereas 0.4% and 0.6% methionine attenuated the induction of NASH by HFCD diet. However, the 0.2% methionine in HFCD diet did not induce insulin resistance, despite the body weight gain.

Conclusions

The 0.2% methionine in HFCD diet for 12 weeks was able to induce NASH without weight loss.

Chronic Moderate Alcohol Intakes Accelerate SR-B1 Mediated Reverse Cholesterol Transport

Cholesterol is essential for all animal life. However, a high level of cholesterol in the body is strongly associated with the progression of various severe diseases. In our study, the potential involvement of alcohol in the regulation of high density lipoprotein (HDL) receptor scavenger receptor class B and type I (SR-B1)-mediated reverse cholesterol transport was investigated. We separated male C57BL/6 mice into four diets: control, alcohol, Control + HC and alcohol + HC. The SR-B1 level and 1,1′-dioctadecyl-3,3,3′,3′-tetramethylindocarbocyanine perchlorate- high- density lipoprotein (DiI-HDL) uptake were also measured in AML12 cells and HL7702 cells treated with alcohol. The control + HC diet led to increased hepatic triglyceride and cholesterol levels while alcohol + HC led no significant change. Compared with that of the control group, the SR-B1 mRNA level was elevated by 27.1% (P < 0.05), 123.8% (P < 0.001) and 343.6% (P < 0.001) in the alcohol, control + HC and alcohol + HC groups, respectively. In AML12 and HL7702 cells, SR-B1 level and DiI-HDL uptake were repressed by SR-B1 siRNA or GW9662. However, these effects were reversed through alcohol treatment. These data suggest that a moderate amount of alcohol plays a novel role in reverse cholesterol transport, mainly mediated by PPARγ and SR-B1.

Influence of High-fat and High-cholesterol Diet on Major CYP Activities in the Liver

We previously reported that a high-fat and high-cholesterol (HFHC) diet for 12 weeks induced non-alcoholic steatohepatitis (NASH) and influenced major CYP subtype gene expression levels and activities in a mouse model. In the present study, we determined the effects of the HFHC diet on CYP expression levels and activities prior to the establishment of NASH. When male C57BL/6J mice were fed the HFHC or a normal chow diet (Control) ad libitum for 4 weeks, body weights were significantly lower, whereas liver weights and hepatic lipid contents were significantly higher in the HFHC group than in the Control group. Under these conditions, hepatic microsomal luciferin-H (human CYP2C9 substrate) hydroxylation activity was significantly lower in the HFHC group than in the Control group. In order to investigate drug efficacy in mice fed the HFHC diet, an intraperitoneal glucose tolerance test was conducted with or without a pretreatment with tolbutamide (a CYP2C substrate) after 4 weeks of feeding. The plasma glucose-lowering effects of tolbutamide were attenuated in the HFHC group even though luciferin-H hydroxylation activity was suppressed in this group. The reason for this discrepancy was attributed to the mRNA expression levels of Cyp2c44 being lower and those of Cyp2c29 and Cyp2c66, which are involved in the metabolism of tolbutamide, being higher in the HFHC group than in the Control group. These results indicate that the expression of Cyp2c in the liver is influenced by the HFHC diet prior to the establishment of NASH and its regulation differed among the subtypes examined.

Animal models of myocardial infarction: Mainstay in clinical translation

Preclinical models with high prognostic power are a prerequisite for translational research. The closer the similarity of a model to myocardial infarction (MI), the higher is the prognostic value for clinical trials. An ideal MI model should present cardinal signs and pathology that resemble the human disease. The increasing understanding of MI stratification and etiology, however, complicates the choice of animal model for preclinical studies. An ultimate animal model, relevant to address all MI related pathophysiology is yet to be developed. However, many of the existing MI models comprising small and large animals are useful in answering specific questions. An appropriate MI model should be selected after considering both the context of the research question and the model properties. This review addresses the strengths, and limitations of current MI models for translational research.

Efficacy of Dietary Lipid Control in Healing High-Fat and High-Cholesterol Diet-Induced Fibrotic Steatohepatitis in Rats

Nonalcoholic steatohepatitis is related to lifestyle, particularly to dietary habits. We developed diet-induced fibrotic steatohepatitis model stroke-prone spontaneously hypertensive 5/Dmcr (SHRSP5/Dmcr) rats showing steatosis, hepatic inflammation, and severe fibrosis induced by high-fat and -cholesterol (HFC) diet feeding. We aimed to clarify the efficacy of dietary intervention on the disease before and after the appearance of fibrosis. Male SHRSP5/Dmcr rats were divided into 9 groups; of these, 6 groups were fed control or HFC diet for several weeks and the remaining 3 groups represented the dietary intervention groups, which were fed the control diet after HFC diet feeding for 2 (before the appearance of fibrosis) or 8 (after the appearance of fibrosis) weeks. Dietary intervention before the appearance of fibrosis significantly improved the steatosis and reset the increased serum aspartate aminotransferase (AST), alanine aminotransferase (ALT), and serum total cholesterol (TC) levels. However, dietary intervention after the appearance of fibrosis was unable to reset the levels of hepatic TC, serum ALT, and fibrogenesis-related markers and had only a minor influence on hepatic fibrosis, although it reset the increased expression of transforming growth factor (TGF)-β1 and α-smooth muscle actin (SMA). It was noted that dietary intervention improved the increased AST levels; however, aggregated CD68-positive cells were still observed around the fibrosis area, which may be related to the findings of inflammatory cytokine mRNAs. Taken together, dietary intervention for fibrotic steatohepatitis improved steatosis, although it could not completely improve fibrosis.

Global publication trends and research hotspots of nonalcoholic fatty liver disease: a bibliometric analysis and systematic review

With the globally increasing prevalence, nonalcoholic fatty liver disease (NAFLD) becomes the predominant cause of chronic liver disease. A global look at the publication trends and the research hotspots of NAFLD are urgently needed to assess the situation of NAFLD research. The global scientific research in the Science Citation Index-Expanded covered articles relevant to NAFLD was retrieved and its bibliometric parameters and research hotspots of NAFLD were systematically evaluated. To sum up, 6356 articles were published in 994 different journals covering 93 SCI subject categories during 1986–2013, in which English was the most predominant language used. Starting from the late 1980s, the publication on NAFLD grew slowly and entered into a highly developing period in the 21st century, especially in the last decade. Besides hepatic steatosis, metabolic syndrome and its combination of symptoms such as obesity, insulin resistance are listed as the top frequent keywords. Bibliometric results suggest that the obviously rapid growth of the articles in recent years appears to be associated with the accelerating incidence of NAFLD and its cofactors such as metabolic syndrome. In addition, epidemiology focusing on comparing different regions and population is attracting ever-growing attention. Meantime, pathology plays an important role in NAFLD research.

Cholesterol induces lipoprotein lipase expression in a tree shrew (Tupaia belangeri chinensis) model of non-alcoholic fatty liver disease

Animal models are indispensible to investigate the pathogenesis and treatments of non-alcoholic fatty liver diseases (NAFLD). Altered cholesterol metabolism has been implicated into the pathogenesis of NAFLD. Here, using high fat, cholesterol and cholate diet (HFHC), we generated a novel tree shrew (Tupaia belangeri chinensis) model of NAFLD, which displayed dyslipidemia with increased levels of plasma alanine aminotransferase (ALT) and aspartate aminotransferase (AST), total cholesterol (TC), low density lipoprotein-cholesterol (LDL-c) and high density lipoprotein-cholesterol (HDL-c), but decreased level of triglycerides (TG). Liver histopathology and genes expression indicated that HFHC diet successfully induced liver steatosis to inflammation and fibrosis progressively within 10 weeks. Moreover, HFHC induced the transcriptional expression of lipoprotein lipase (lpl) in the liver, but repressed the expression of LDL receptor, and the endogenous synthesis pathway and excretion of cholesterol. Notably, Poloxamer 407 (P-407) inhibition of LPL improved the severity of steatosis and reduced inflammation. These results illustrated that LPL plays an important role in cholesterol metabolism in NAFLD, and the tree shrew may be a valuable animal model for further research into NAFLD.

Regulation effect of Aspirin Eugenol Ester on blood lipids in Wistar rats with hyperlipidemia

Background

Aspirin eugenol ester (AEE) is a promising drug candidate for treatment of inflammation, pain and fever and prevention of cardiovascular diseases with less side effects. The experiment will be conducted to investigate the efficacy of AEE on curing hyperlipidemia in Wistar rats. The rats were fed with high fat diet (HFD) for 8 weeks to induce hyperlipidemia.

Results

Compared with the model group, the results showed that AEE at 54 mg/kg dosage could significantly decrease the hyperlipidemia indexes including triglyceride (TG), low density lipoprotein (LDL) and total cholesterol (TCH) (p < 0.01), increase high density lipoprotein (HDL) (p < 0.05) for five weeks drug administration. Meanwhile, simvastatin had same effect on hyperlipidemia indexes such as TG, LDL, TC, but no significant increase in HDL.

Conclusion

AEE was effective against hyperlipidemia and had better anti-hyperlipidemic effect than its component, acetylsalicylic acid (Aspirin, ASA), eugenol and integration of ASA and eugenol. Under the experimental circumstance, the optimal dose of AEE to cure hyperlipidemia is 54 mg/kg for five weeks in Wistar rats.

Hypolipidemic effects of Solidago chilensis hydroalcoholic extract and its major isolated constituent quercetrin in cholesterol-fed rats

CONTEXT

Despite several studies on the effects of Solidago chilensis Meyen (Asteraceae), the phytochemical and hypolipidemic properties remain underappreciated.

OBJECTIVE

This study evaluates the hypolipidemic and antioxidant effects of hydroalcoholic extract (HE) and quercetrin from S. chilensis aerial parts in cholesterol-fed rats.

MATERIALS AND METHODS

The HE was analyzed by high-performance liquid chromatography, followed by quercetrin isolation. Hypercholesterolemic rats (1% cholesterol and 0.5% cholic acid for 15 d) were treated with HE (150, 300, and 600 mg/kg p.o.; n = 6), simvastatin (4 mg/kg p.o.; n = 6), or quercetrin (10 mg/kg p.o.; n = 6) once a day for 30 d. During this period, a high-cholesterol diet was maintained until the 30th day of treatment.

RESULTS

Rats treated with HE (150, 300, and 600 mg/kg) and quercetrin showed decreased serum levels of total cholesterol (-19.9, -27.5, -31.0, and -39.4%), lipoprotein-cholesterol (-36.0, -37.5, -43.3, and -59.4%), and triacylglycerides (-15.6, -23.5, -29.8, and -27.2%) when compared with the control group similar to simvastatin. Moreover, treatment with HE and quercetrin decreased hepatic 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase activity (35.1% on average) and increased fecal cholesterol levels (38.2% on average).

DISCUSSION AND CONCLUSIONS

Our results suggest that hypolipidemic effects of HE are associated with it modulating the activity of HMG-CoA reductase and its interference in the reabsorption and/or excretion of intestinal lipids. Solidago chilensis and its main constituent, quercetrin, may thus be effective as cholesterol-lowering agents and in preventing atherosclerosis.

High-fat and high-cholesterol diet rapidly induces non-alcoholic steatohepatitis with advanced fibrosis in Sprague-Dawley rats

AIM

The development of fibrosis is considered an important phase in the progress of non-alcoholic steatohepatitis (NASH) towards the end stage of liver disease, including cirrhosis. However, few small animal models can display NASH-associated fibrosis. We aimed to establish a dietary model of NASH with rapid progression to fibrosis using genetically normal rats.

METHODS

Nine-week-old male Sprague-Dawley rats were fed with normal, high-fat (HF), or two types of high-fat and high-cholesterol (HFC) diets for 9 weeks (n = 5 each). All HFC diets contained 1.25% or 2.5% cholesterol.

RESULTS

The rats fed with the HF diet developed mild steatosis and inflammation without fibrosis at 18 weeks of age, whereas all rats given the HFC diet developed obvious steatosis and inflammation with hepatocyte ballooning and fibrosis. Two of five (40%) rats given the HFC diet containing 2.5% cholesterol progressed to liver cirrhosis. Hepatic total cholesterol levels were significantly higher in rats given the HFC, than the normal or HF diets. The HFC diet significantly and dose-dependently decreased microsomal triglyceride transfer protein expression. Cholesterol tended to suppress carnitine palmitoyltransferase activity and adenosine triphosphate-binding cassette transporter G5 expression. Adding cholesterol to the HF diet modified hepatic lipid metabolism at the molecular level.

CONCLUSION

The HFC diet induced hepatic features of NASH and eventually progressed cirrhosis in Sprague-Dawley rats within 9 weeks.

Phaleria macrocarpa Boerl. (Thymelaeaceae) leaves increase SR-BI expression and reduce cholesterol levels in rats fed a high cholesterol diet

In vitro and in vivo studies of the activity of Phaleria macrocarpa Boerl (Thymelaeaceae) leaves against the therapeutic target for hypercholesterolemia were done using the HDL receptor (SR-BI) and hypercholesterolemia-induced Sprague Dawley rats. The in vitro study showed that the active fraction (CF6) obtained from the ethyl acetate extract (EMD) and its component 2',6',4-trihydroxy-4'-methoxybenzophenone increased the SR-BI expression by 95% and 60%, respectively. The in vivo study has proven the effect of EMD at 0.5 g/kgbw dosage in reducing the total cholesterol level by 224.9% and increasing the HDL cholesterol level by 157% compared to the cholesterol group. In the toxicity study, serum glutamate oxalate transaminase (SGOT) and serum glutamate pyruvate transaminase (SGPT) activity were observed to be at normal levels. The liver histology also proved no toxicity and abnormalities in any of the treatment groups, so it can be categorized as non-toxic to the rat liver. The findings taken together show that P. macrocarpa leaves are safe and suitable as an alternative control and prevention treatment for hypercholesterolemia in Sprague Dawley rats.

Gadoxetic acid-enhanced MRI and sonoelastography: non-invasive assessments of chemoprevention of liver fibrosis in thioacetamide-induced rats with Sho-Saiko-To

Background

This study aimed to compare the performance of gadoxetic acid -enhanced magnetic resonance imaging (MRI) and sonoelastography in evaluating chemopreventive effects of Sho-Saiko-To (SST) in thioacetamide (TAA)-induced early liver fibrosis in rats.

Materials and Methods

Ten of Sprague-Dawley rats receiving TAA (200 mg/kg of body weight) intraperitoneal injection were divided into three groups: Group 1 (TAA only, n = 3), Group 2 (TAA +0.25 g/kg SST, n = 4) and Group 3 (TAA+1 g/kg SST, n = 3). Core needle liver biopsy at week 2 and liver specimens after sacrifice at week 6 confirmed liver fibrosis using histological examinations, including Sirius red staining, Ishak and Metavir scoring systems. Gadoxetic acid-enhanced MRI and shear-wave sonoelastography were employed to evaluate liver fibrosis. The expression of hepatic transporter organic anion transporter 1 (Oatp1), multidrug-resistant protein 2 (Mrp2) and alpha-smooth muscle actin (α-Sma) were also analyzed in each group by immunohistochemistry (IHC) and Western blot.

Results

According to histological grading by Sirius red staining, Ishak scores of liver fibrosis in Groups 1, 2 and 3 were 3, 2 and 1, respectively. As shown in gadoxetic acid-enhanced MRI, the ratio of relative enhancement was significantly lower in Group 1 (1.87±0.21) than in Group 2 of low-dose (2.82±0.25) and Group 3 of high-dose (2.72±0.12) SST treatment at 10 minutes after gadoxetic acid intravenous injection (p<0.05). Sonoelastography showed that the mean difference before and after experiments in Groups 1, 2 and 3 were 4.66±0.1, 4.4±0.57 and 3±0.4 KPa (p<0.1), respectively. Chemopreventive effects of SST reduced the Mrp2 protein level (p<0.01) but not Oatp1 and α-Sma levels.

Conclusion

Sonoelastography and gadoxetic acid-enhanced MRI could monitor the treatment effect of SST in an animal model of early hepatic fibrosis.

Cytoplasmic tyrosine phosphatase Shp2 coordinates hepatic regulation of bile acid and FGF15/19 signaling to repress bile acid synthesis

Bile acid (BA) biosynthesis is tightly controlled by intrahepatic negative feedback signaling elicited by BA binding to farnesoid X receptor (FXR) and also by enterohepatic communication involving ileal BA reabsorption and FGF15/19 secretion. However, how these pathways are coordinated is poorly understood. We show here that nonreceptor tyrosine phosphatase Shp2 is a critical player that couples and regulates the intrahepatic and enterohepatic signals for repression of BA synthesis. Ablating Shp2 in hepatocytes suppressed signal relay from FGFR4, receptor for FGF15/19, and attenuated BA activation of FXR signaling, resulting in elevation of systemic BA levels and chronic hepatobiliary disorders in mice. Acting immediately downstream of FGFR4, Shp2 associates with FRS2α and promotes the receptor activation and signal relay to several pathways. These results elucidate a molecular mechanism for the control of BA homeostasis by Shp2 through the orchestration of multiple signals in hepatocytes.

Red yeast rice and coenzyme Q10 as safe alternatives to surmount atorvastatin-induced myopathy in hyperlipidemic rats

Statins are the first line treatment for the management of hyperlipidemia. However, the primary adverse effect limiting their use is myopathy. This study examines the efficacy and safety of red yeast rice (RYR), a source of natural statins, as compared with atorvastatin, which is the most widely used synthetic statin. Statin interference with the endogenous synthesis of coenzyme Q10 (CoQ10) prompted the hypothesis that its deficiency may be implicated in the pathogenesis of statin-associated myopathy. Hence, the effects of combination of CoQ10 with either statin have been evaluated. Rats were rendered hyperlipidemic through feeding them a high-fat diet for 90 days, during the last 30 days of the diet they were treated daily with either atorvastatin, RYR, CoQ10, or combined regimens. Lipid profile, liver function tests, and creatine kinase were monitored after 15 and 30 days of drug treatments. Heart contents of CoQ9 and CoQ10 were assessed and histopathological examination of the liver and aortic wall was performed. RYR and CoQ10 had the advantage over atorvastatin in that they lower cholesterol without elevating creatine kinase, a hallmark of myopathy. RYR maintained normal levels of heart ubiquinones, which are essential components for energy production in muscles. In conclusion, RYR and CoQ10 may offer alternatives to overcome atorvastatin-associated myopathy.

In vitro and in vivo models of non-alcoholic fatty liver disease (NAFLD)

By now, non-alcoholic fatty liver disease (NAFLD) is considered to be among the most common liver diseases world-wide. NAFLD encompasses a broad spectrum of pathological conditions ranging from simple steatosis to steatohepatitis, fibrosis and finally even cirrhosis; however, only a minority of patients progress to end-stages of the disease, and the course of the disease progression to the later stages seems to be slow, developing progressively over several years. Key risk factors including overweight, insulin resistance, a sedentary life-style and an altered dietary pattern, as well as genetic factors and disturbances of the intestinal barrier function have been identified in recent years. Despite intense research efforts that lead to the identification of these risk factors, knowledge about disease initiation and molecular mechanisms involved in progression is still limited. This review summarizes diet-induced and genetic animal models, as well as cell culture models commonly used in recent years to add to the understanding of the mechanisms involved in NAFLD, also referring to their advantages and disadvantages.

Animal models of chronic liver diseases

Chronic liver diseases are frequent and potentially life threatening for humans. The underlying etiologies are diverse, ranging from viral infections, autoimmune disorders, and intoxications (including alcohol abuse) to imbalanced diets. Although at early stages of disease the liver regenerates in the absence of the insult, advanced stages cannot be healed and may require organ transplantation. A better understanding of underlying mechanisms is mandatory for the design of new drugs to be used in clinic. Therefore, rodent models are being developed to mimic human liver disease. However, no model to date can completely recapitulate the "corresponding" human disorder. Limiting factors are the time frame required in humans to establish a certain liver disease and the fact that rodents possess a distinct immune system compared with humans and have different metabolic rates affecting liver homeostasis. These features account for the difficulties in developing adequate rodent models for studying disease progression and for testing new pharmaceuticals to be translated into the clinic. Nevertheless, traditional and new promising animal models that mimic certain attributes of chronic liver diseases are established and being used to deepen our understanding in the underlying mechanisms of distinct liver diseases. This review aims at providing a comprehensive overview of recent advances in animal models recapitulating different features and etiologies of human liver diseases.

Rosuvastatin ameliorates high-fat and high-cholesterol diet-induced nonalcoholic steatohepatitis in rats

BACKGROUND/AIMS

Statins, which are inhibitors of 3-hydroxy-3-methylglutaryl coenzyme A reductase and inhibit endogenous cholesterol synthesis, possess pleiotropic activities, such as anti-inflammatory, anti-oxidative and antifibrotic effects. Here, we investigated whether statins ameliorate steatohepatitis using a high-fat and high-cholesterol (HFHC) diet-induced rat model.

METHODS

Eight-week-old male Sprague-Dawley rats were fed control chow or HFHC diet. Half of the HFHC diet-fed rats were orally administered 2 mg/kg/day rosuvastatin for 12 weeks. Hepatic injury, steatosis, fibrosis and markers of lipid peroxidation/oxidant stress were evaluated.

RESULTS

As previously reported, HFHC diet induced steatohepatitis in rat livers with hypercholesterolaemia. Rosuvastatin decreased Oil Red O stained-positive areas, liver/body weight ratio, serum total cholesterol levels and hepatic free fatty acid contents in HFHC diet-fed rats. Further study revealed that rosuvastatin significantly decreased hepatic mRNA expression of tumour necrosis factor-α and interleukin-6, serum alanine aminotransferase levels and hepatic lobular inflammation grade. Hepatic fibrosis was also ameliorated by rosuvastatin with decreases in hepatic mRNA expression of transforming growth factor-β, connective tissue growth factor and type-1 procollagen. Similarly, hepatic Sirius red stained or α-smooth muscle actin stained-positive areas and expression of markers of lipid peroxidation/oxidant stress [hepatic 8-hydroxy-oxyguanosine and hepatic 4-hydroxy-2-nonenal] were decreased. Interestingly, whereas the expression of carnitine palmitoyltransferase-1 and long-chain acyl-CoA dehydrogenase was not affected, that of catalase and acyl-coA oxidase was restored.

CONCLUSIONS

These data suggest that rosuvastatin improved not only hepatic steatosis but also hepatic injury and fibrosis via improved peroxisomal β-oxidation in this rat HFHC model.

Changes in the hepatic mitochondrial and membrane proteome in mice fed a non-alcoholic steatohepatitis inducing diet

Non-alcoholic steatohepatitis (NASH) accounts for a large proportion of cryptic cirrhosis in the Western societies. Nevertheless, we lack a deeper understanding of the underlying pathomolecular processes, particularly those preceding hepatic inflammation and fibrosis. In order to gain novel insights into early NASH-development from the first appearance of proteomic alterations to the onset of hepatic inflammation and fibrosis, we conducted a time-course analysis of proteomic changes in liver mitochondria and membrane-enriched fractions of female C57Bl/6N mice fed either a mere steatosis or NASH inducing diet. This data was complemented by quantitative measurements of hepatic glycerol-containing lipids, cholesterol and intermediates of the methionine cycle. Aside from energy metabolism and stress response proteins, enzymes of the urea cycle and methionine metabolism were found regulated. Alterations in the methionine cycle occur early in disease progression preceding molecular signs of inflammation. Proteins that hold particular promise in the early distinction between benign steatosis and NASH are methyl-transferase Mettl7b, the glycoprotein basigin and the microsomal glutathione-transferase.

Sources of cells that contribute to atherosclerotic intimal calcification: an in vivo genetic fate mapping study

AIMS

Vascular cartilaginous metaplasia and calcification are common in patients with atherosclerosis. However, sources of cells contributing to the development of this complication are currently unknown. In this study, we ascertained the origin of cells that give rise to cartilaginous and bony elements in atherosclerotic vessels.

METHODS AND RESULTS

We utilized genetic fate mapping strategies to trace cells of smooth muscle (SM) origin via SM22α-Cre recombinase and Rosa26-LacZ Cre reporter alleles. In animals expressing both transgenes, co-existence within a single cell of β-galactosidase [marking cells originally derived from SM cells (SMCs)] with osteochondrogenic (Runx2/Cbfa1) or chondrocytic (Sox9, type II collagen) markers, along with simultaneous loss of SM lineage proteins, provides a strong evidence supporting reprogramming of SMCs towards osteochondrogenic or chondrocytic differentiation. Using this technique, we found that vascular SMCs accounted for ~80% of Runx2/Cbfa1-positive cells and almost all of type II collagen-positive cells (~98%) in atherosclerotic vessels of LDLr-/- and ApoE-/- mice. We also assessed contribution from bone marrow (BM)-derived cells via analysing vessels dissected from chimerical ApoE-/- mice transplanted with green fluorescence protein-expressing BM. Marrow-derived cells were found to account for ~20% of Runx2/Cbfa1-positive cells in calcified atherosclerotic vessels of ApoE-/- mice.

CONCLUSION

Our results are the first to definitively identify cell sources attributable to atherosclerotic intimal calcification. SMCs were found to be a major contributor that reprogrammed its lineage towards osteochondrogenesis. Marrow-derived cells from the circulation also contributed significantly to the early osteochondrogenic differentiation in atherosclerotic vessels.

Therapeutic effects of ezetimibe for non-alcoholic steatohepatitis in fatty liver shionogi-ob/ob mice

AIM

  An effective therapy for non-alcoholic steatohepatitis has yet to be defined. This study examined the therapeutic effects of ezetimibe, a lipid-lowering medication, on steatosis and hepatic fibrosis in fatty liver Shionogi ob/ob (FLS-ob) mice.

METHODS

  Low-dose (0.2 mg/kg body weight) and high-dose (1.0 mg/kg body weight) of ezetimibe were administered to FLS-ob mice orally for 12 weeks.

RESULTS

  Administration of ezetimibe significantly and dose-dependently decreased liver cholesterol content. The area of hepatic fibrosis and hepatic hydroxyproline content in the low- and high-dose groups were significantly decreased compared with controls. Areas of α-smooth muscle actin positivity and F4/80 positivity were significantly decreased in a dose-dependent manner. Percentages of 8-hydroxy-2-deoxyguanosine-positive cells in low- and high-dose groups were significantly decreased compared with those in controls, and 8-hydroxy-2-deoxyguanosine DNA content and thiobarbituric acid reactive substances in the high-dose group was also significantly decreased compared to controls. Gene expression levels of procollagen I and transforming growth factor β1 mRNA levels were lower in the low- and high-dose groups than in controls. Tumor necrosis factor-α and sterol regulatory element-binding protein 1c mRNA levels were also lower in the low- and high-dose groups than in controls.

CONCLUSIONS

  Ezetimibe attenuated steatosis and liver fibrosis by reducing oxidative stress and lipid peroxidation and suppressing activated hepatic stellate cells and Kupffer cells.