Nutrition and nonalcoholic Fatty liver disease: the significance of cholesterol

Impact of Seipin in cholesterol mediated lipid droplet maturation; status of endoplasmic reticulum stress and lipophagy

The global prevalence of nonalcoholic fatty liver disease (NAFLD) defined by the increased number of lipid droplets (LDs) in hepatocytes, have risen continuously in parallel with the obesity. LDs and related proteins are known to affect cellular metabolism and signaling. Seipin, one of the most important LD-related proteins, plays a critical role in LD biogenesis. Although the role of adipose tissue-specific Seipin silencing is known, hepatocyte-specific silencing upon cholesterol-mediated lipid accumulation has not been investigated. In our study, we investigated the effect of Seipin on endoplasmic reticulum (ER) stress and lipophagy in cholesterol accumulated mouse hepatocyte cells. In this direction, cholesterol accumulation was induced by cholesterol-containing liposome, while Seipin mRNA and protein levels were reduced by siRNA. Our findings show that cholesterol containing liposome administration in hepatocytes increases both Seipin protein and number of large LDs. However Seipin silencing reduced the increase of cholesterol mediated large LDs and Glucose-regulated protein 78 (GRP78) mRNA. Additionally, lysosome-LD colocalization increased only in cells treated with cholesterol containing liposome, while the siRNA against Seipin did not lead any significant difference. According to our findings, we hypothesize that Seipin silencing in hepatocytes reduced cholesterol mediated LD maturation as well as GRP78 levels, but not lipophagy.

MAFLD: an ideal framework for understanding disease phenotype in individuals of normal weight

The prevalence of metabolic dysfunction-associated fatty liver disease (MAFLD) is significant, impacting almost one-third of the global population. MAFLD constitutes a primary cause of end-stage liver disease, liver cancer and the need for liver transplantation. Moreover, it has a strong association with increased mortality rates due to various extrahepatic complications, notably cardiometabolic diseases. While MAFLD is typically correlated with obesity, not all individuals with obesity develop the disease and a significant percentage of MAFLD occurs in patients without obesity, termed lean MAFLD. The clinical features, progression and underlying physiological mechanisms of patients with lean MAFLD remain inadequately characterized. The present review aims to provide a comprehensive summary of current knowledge on lean MAFLD and offer a perspective on defining MAFLD in individuals with normal weight. Key to this process is the concept of metabolic health and flexibility, which links states of dysmetabolism to the development of lean MAFLD. This perspective offers a more nuanced understanding of MAFLD and its underlying mechanisms and highlights the importance of considering the broader metabolic context in which the disease occurs. It also bridges the knowledge gap and offers insights that can inform clinical practice.

Effects of Egg Consumption on Subjects with SLD or Hypertension: A MICOL Study

BACKGROUND

Steatotic liver disease (SLD) is defined as a fat accumulation in more than 5% of hepatocytes; it can progress to non-alcoholic steatohepatitis (NASH), associated with an increased state of inflammation. The aim of this study was to explore the protective effects of eating eggs and any association with SLD and hypertension (HTN).

METHODS

The study cohort included 908 participants assessed in the fourth recall of the MICOL study, grouped into four groups, based on NALFD and/or HTN.

RESULTS

The prevalence of HTN and SLD among participants was 31.61%. Overall, the results indicated a statistical significance of egg consumption, showing a protective role against the two disease conditions, in both the raw and adjusted models (RRR = 0.34, p = 0.009, 0.15 to 0.76 95% C.I.).

CONCLUSIONS

Many differences were found among the groups, and the protective role of eating eggs was amply demonstrated. We can conclude that it is unwise to demonize the intake of this food and its nutritional properties, in contrast with previous reports in the literature.

Safety evaluation of saffron extracts in early and established atherosclerotic New Zealand white rabbits

Previous research has shown that natural medications pose health risks, especially in subjects with comorbidities. This study aimed to evaluate the safety of saffron ethanolic extract (SEE) administration in early and established atherosclerotic rabbits. Rabbits were given a high-cholesterol diet (HCD) for 4 and 8 weeks to induce early and established atherosclerosis respectively, and then they were treated with 50 and 100 mg/kg/day SEE. The body weight of the animals was recorded. Blood samples were collected at baseline, pre-treatment, and post-treatment for hematological studies, lipid profiles, and biochemical profiles. Tissue specimens of the vital organs were subjected to histological examination. The above parameters were significantly altered post-intervention with 4 and 8 weeks of HCD. No significant differences in body weight were observed in all the groups post-treatment with 50 and 100mg/kg of SEE compared to pre-treatment. However, low-density lipoprotein cholesterol, total cholesterol, serum urea, and glucose significantly decreased post-treatment with 50 and 100mg/kg/day SEE compared to pre-treatment in early and established atherosclerosis groups. Hematological parameters that were affected post-intervention with HCD returned to their baseline values post-treatment with 50 and 100mg/kg/day SEE. There was a significant improvement in the vital organs post-treatment with 50 and 100mg/kg SEE. SEE can safely be administered without causing harmful effects on the hematological, biochemical profiles, and vital organs. Notably, SEE exerts hypolipidemic and hypoglycemic effects on atherosclerotic conditions. Further clinical trials are warranted to ensure the safety of saffron administration in patients with atherosclerosis-related diseases.

The roles of nuclear receptors in cholesterol metabolism and reverse cholesterol transport in nonalcoholic fatty liver disease

As the most prevalent chronic liver disease globally, NAFLD encompasses a pathological process that ranges from simple steatosis to NASH, fibrosis, cirrhosis, and HCC, closely associated with numerous extrahepatic diseases. While the initial etiology was believed to be hepatocyte injury caused by lipid toxicity from accumulated triglycerides, recent studies suggest that an imbalance of cholesterol homeostasis is of greater significance. The role of nuclear receptors in regulating liver cholesterol homeostasis has been demonstrated to be crucial. This review summarizes the roles and regulatory mechanisms of nuclear receptors in the 3 main aspects of cholesterol production, excretion, and storage in the liver, as well as their cross talk in reverse cholesterol transport. It is hoped that this review will offer new insights and theoretical foundations for the study of the pathogenesis and progression of NAFLD and provide new research directions for extrahepatic diseases associated with NAFLD.

Clinical Classification of Obesity and Implications for Metabolic Dysfunction-Associated Fatty Liver Disease and Treatment

Obesity,and metabolic dysfunction-associated fatty liver disease (MAFLD) have reached epidemic proportions globally. Obesity and MAFLD frequently coexist and act synergistically to increase the risk of adverse clinical outcomes (both hepatic and extrahepatic). Type 2 diabetes mellitus (T2DM) is the most important risk factor for rapid progression of steatohepatitis and advanced fibrosis. Conversely, the later stages of MAFLD are associated with an increased risk of T2DM incident. According to the proposed criteria, MAFLD is diagnosed in patients with liver steatosis and in at least one in three: overweight or obese, T2DM, or signs of metabolic dysregulation if they are of normal weight. However, the clinical classification and correlation between obesity and MAFLD is more complex than expected. In addition, treatment for obesity and MAFLD are associated with a reduced risk of T2DM, suggesting that liver-based treatments could reduce the risk of developing T2DM. This review describes the clinical classification of obesity and MAFLD, discusses the clinical features of various types of obesity and MAFLD, emphasizes the role of visceral obesity and insulin resistance (IR) in the development of MAFLD,and summarizes the existing treatments for obesity and MAFLD that reduce the risk of developing T2DM.

Nonalcoholic Fatty Liver Disease in Lean/Nonobese and Obese Individuals: A Comprehensive Review on Prevalence, Pathogenesis, Clinical Outcomes, and Treatment

Nonalcoholic fatty liver disease (NAFLD) is the most common liver disease worldwide, with an estimated prevalence of 25% globally. NAFLD is closely associated with metabolic syndrome, which are both becoming increasingly more common with increasing rates of insulin resistance, dyslipidemia, and hypertension. Although NAFLD is strongly associated with obesity, lean or nonobese NAFLD is a relatively new phenotype and occurs in patients without increased waist circumference and with or without visceral fat. Currently, there is limited literature comparing and illustrating the differences between lean/nonobese and obese NAFLD patients with regard to risk factors, pathophysiology, and clinical outcomes. In this review, we aim to define and further delineate different phenotypes of NAFLD and present a comprehensive review on the prevalence, incidence, risk factors, genetic predisposition, and pathophysiology. Furthermore, we discuss and compare the clinical outcomes, such as insulin resistance, dyslipidemia, hypertension, coronary artery disease, mortality, and progression to nonalcoholic steatohepatitis, among lean/nonobese and obese NAFLD patients. Finally, we summarize the most up to date current management of NAFLD, including lifestyle interventions, pharmacologic therapies, and surgical options.

Protective effects and mechanisms of Lizhong decoction against non-alcoholic fatty liver disease in a rat model

OBJECTIVE

To investigate the protective effects and molecular mechanisms of Lizhong decoction (, LZD) against non-alcoholic fatty liver disease (NAFLD).

METHODS

Male Wistar rats were fed a high-fat diet for four weeks to induce NAFLD, and were administered LZD by gavage for four weeks. Potential therapeutic targets for NAFLD were analyzed using network pharmacology. Liver pathology was evaluated using Oil Red O and hematoxylin-eosin staining. Furthermore, mitochondrial function, lipid metabolism, oxidative stress, and inflammatory response were examined.

RESULTS

Rats with NAFLD exhibited high levels of hepatic damage and cholesterol deposition. Moreover, apoptosis was increased, superoxide dismutase and glutathione content were reduced, malondialdehyde content was increased, and the protein expression of inflammatory cytokines and p-c-Jun N-terminal kinase was increased. The LZD treatment ameliorated mitochondrial dysfunction, reduced liver damage, inhibited oxidative stress and inflammatory response, upregulated peroxisome proliferator-activated receptor (PPAR)-γ expression, and suppressed dipeptidyl peptidase 4 (DPP4) expression in the liver.

CONCLUSION

It was found that LZD alleviates NAFLD by activating PPAR-γ and inhibiting DPP4.

Cholesterol accumulation in hepatocytes mediates IRE1/p38 branch of endoplasmic reticulum stress to promote nonalcoholic steatohepatitis

Non-alcoholic fatty liver disease (NAFLD), based on the elevating obesity incidence, is one of the major health issue worldwide. Transition from NAFLD to non-alcoholic steatohepatitis (NASH) is driven by increased apoptosis and is relevant to higher morbidity rates. In regard to limited understanding on cholesterol mediated hepatocyte alterations in NALFD/NASH transition, we investigated endoplasmic reticulum (ER) stress and related apoptosis. Our findings suggest that cholesterol upregulates ER stress and enhances C/EBP homologous protein (CHOP) either in hypercholesterolemic rabbits or in hepatocytes treated with liposome-cholesterol complex. Mechanistically, cholesterol accumulation in hepatocytes activates IRE1/p38 branch of ER stress, stimulating CHOP levels. In liver tissues of cholesterol fed rabbits, α-tocopherol supplementation decreased IRE1/p38/CHOP activation and prevented NASH development. Thus, our study provides a critical role of hepatocyte cholesterol in inducing IRE1/p38/CHOP pathway and suggests novel candidates for therapeutic targets against NASH.

Metabolic (dysfunction)-associated fatty liver disease in individuals of normal weight

Metabolic (dysfunction)-associated fatty liver disease (MAFLD) affects up to a third of the global population; its burden has grown in parallel with rising rates of type 2 diabetes mellitus and obesity. MAFLD increases the risk of end-stage liver disease, hepatocellular carcinoma, death and liver transplantation and has extrahepatic consequences, including cardiometabolic disease and cancers. Although typically associated with obesity, there is accumulating evidence that not all people with overweight or obesity develop fatty liver disease. On the other hand, a considerable proportion of patients with MAFLD are of normal weight, indicating the importance of metabolic health in the pathogenesis of the disease regardless of body mass index. The clinical profile, natural history and pathophysiology of patients with so-called lean MAFLD are not well characterized. In this Review, we provide epidemiological data on this group of patients and consider overall metabolic health and metabolic adaptation as a framework to best explain the pathogenesis of MAFLD and its heterogeneity in individuals of normal weight and in those who are above normal weight. This framework provides a conceptual schema for interrogating the MAFLD phenotype in individuals of normal weight that can translate to novel approaches for diagnosis and patient care.

The effects of L-carnitine-loaded solid lipid nanoparticles on performance, antioxidant parameters, and expression of genes associated with cholesterol metabolism in laying hens

The purpose of this study was to investigate the production performance, antioxidant parameters, egg yolk cholesterol content, and expression of genes related to cholesterol metabolism in laying hens fed L-carnitine (LC) and L-carnitine-loaded solid lipid nanoparticles (LC-SLNs). A total of 350 Hy-Line (w-36) laying hens at 50 wk of age (1520.0 ± 0.7 g) were randomly assigned to 35 units (5 replicates and 50 hens in each treatment) with seven dietary treatments as a completely randomized design. The dietary treatments were corn-soybean meal-based diets, including 1) Control (basal diet); 2) Basal diet +50 mg/kg LC (50LC); 3) Basal diet +100 mg/kg LC (100LC); 4) Basal diet +150 mg/kg LC (150LC); 5) Basal diet +50 mg/kg LC-SLNs (50LC-SLNs); 6) Basal diet +100 mg/kg LC-SLNs (100LC-SLNs) and 7) Basal diet +150 mg/kg LC-SLNs (150LC-SLNs). Results showed that the 50LC-SLNs had the least feed conversion ratio (FCR) in all groups (P < 0.05). The dietary supplementation of 100LC-SLNs decreased (P < 0.01) the egg yolk cholesterol concentration from 14.71 to 11.76 mg/g yolk (25%). The 50LC-SLNs group produced the most total antioxidant capacity with a difference of 58.44% compared to the control group (P < 0.01). The greatest amount of total superoxide dismutase was found for 50LC-SLNs (P < 0.05), while the glutathione peroxidase was not affected by the experimental treatments (P > 0.05). Serum malondialdehyde levels were reduced by 50.52% in laying hens fed 50LC-SLNs compared to the control group (P < 0.05). The transcript level of 3-hydroxy-3-methylglutaryl coenzyme A reductase was significantly decreased (P < 0.01) in the LC and LC-SLNs groups. The expression of cholesterol 7α-hydroxylase was significantly increased (P < 0.01) in the plain LC (∼83%) and LC-SLNs (∼91%) groups. The inclusion of LC-SLNs in the diet increased (P < 0.05) the villus height and decreased villus width in all three parts of the small intestine. Dietary inclusion of LC was found to reduce egg yolk and serum cholesterol content by improving the production performance and antioxidant status. The LC-SLNs groups were more affected than the plain LC groups, which may be attributed to the increased bioavailability of LC.

Metabolic dysfunction and cancer in HCV: Shared pathways and mutual interactions

HCV hijacks many host metabolic processes in an effort to aid viral replication. The resulting hepatic metabolic dysfunction underpins many of the hepatic and extrahepatic manifestations of chronic hepatitis C (CHC). However, the natural history of CHC is also substantially influenced by the host metabolic status: obesity, insulin resistance and hepatic steatosis are major determinants of CHC progression toward hepatocellular carcinoma (HCC). Direct-acting antivirals (DAAs) have transformed the treatment and natural history of CHC. While DAA therapy effectively eradicates the virus, the long-lasting overlapping metabolic disease can persist, especially in the presence of obesity, increasing the risk of liver disease progression. This review covers the mechanisms by which HCV tunes hepatic and systemic metabolism, highlighting how systemic metabolic disturbance, lipotoxicity and chronic inflammation favour disease progression and a precancerous niche. We also highlight the therapeutic implications of sustained metabolic dysfunction following sustained virologic response as well as considerations for patients who develop HCC on the background of metabolic dysfunction.

Hepatic Steatosis in the Mouse Model of Wilson Disease Coincides with a Muted Inflammatory Response

Wilson disease (WND) is caused by inactivation of the copper transporter ATP7B and copper accumulation in tissues. WND presentations vary from liver steatosis to inflammation, fibrosis, and liver failure. Diets influence the liver phenotype in WND, but findings are inconsistent. To better understand the impact of excess calories on liver phenotype in WND, the study compared C57BL/6J Atp7b-/- and C57BL/6J mice fed for 12 weeks with Western diet or normal chow. Serum and liver metabolites, body fat content, liver histology, hepatic proteome, and copper content were analyzed. Wild-type and Atp7b-/- livers showed striking similarities in their responses to Western diet, most notably down-regulation of cholesterol biosynthesis, altered nuclear receptor signaling, and changes in cytoskeleton. Western diet increased body fat content and induced liver steatosis in males and females regardless of genotype; however, the effects were less pronounced in Atp7b-/- mice compared with those in the wild type mice. Although hepatic copper remained elevated in Atp7b-/- mice, liver inflammation was reduced. The diet diminished signaling by Rho GTPases, integrin, IL8, and reversed changes in cell cycle machinery and cytoskeleton. Overall, high calories decreased inflammatory response in favor of steatosis without improving markers of cell viability. Similar changes of cellular pathways during steatosis development in wild-type and Atp7b-/- mice explain histologic overlap between WND and non-alcoholic fatty liver disease despite opposite copper changes in these disorders.

Serum anandamide level as a potential indicator for nonalcoholic fatty liver disease severity

INTRODUCTION AND AIM

Nonalcoholic fatty liver disease (NAFLD) is a very common disease, ranging from simple steatosis to nonalcoholic steatohepatitis (NASH) and is considered the hepatic expression of metabolic syndrome. Liver biopsy is currently considered the gold standard in diagnosis of NAFLD; however, it is an invasive technique and carries many risks. The serum anandamide level is recently discovered to play an important role as the potential indicator for NAFLD severity. The purpose of the study is to determine the association of endocannabinoid metabolite anandamide and NAFLD severity and to investigate its association with anthropometric and metabolic features in NAFLD patients.

METHODOLOGY

A case-control study on 36 NAFLD biopsy-proven NAFLD patients and 15 healthy volunteers. They were subjected to full clinical history and examination, laboratory tests, abdominal ultrasound and serological testing of anadamide.

RESULTS

The anadamide level was significantly higher among NAFLD subgroups (simple steatosis and NASH) vs. the normal group (1.1, 0.29 vs. 0.2 P value = 0.00085), with cutoff 0.58 in the NASH group (accuracy 89%; sensitivity 66% and specificity 100%) (P value < 0.01).

CONCLUSION

Anandamide could be a specific serum marker for NASH and can be used to detect NAFLD severity.

Comparison of the Improvement Effect of Deep Ocean Water with Different Mineral Composition on the High Fat Diet-Induced Blood Lipid and Nonalcoholic Fatty Liver Disease in a Mouse Model

Accumulated lipid droplets in liver cause nonalcoholic fatty liver disease (NAFLD). Deep ocean water (DOW) containing high levels of magnesium, calcium, and potassium, etc. was proven to suppress hepatic lipid in obese rats fed high fat diet in the previous study. However, the effect of mineral compositions of DOW on the prevention of NAFLD is still unclear. This study removed calcium and potassium from DOW for modulating the mineral composition, and further compared the effects of DOW (D1(Mg + Ca + K)), DOW with low potassium (D2(Mg + Ca)), and DOW with low calcium and potassium (D3(Mg)) on the prevention of NAFLD in the mice model fed with high fat diet. In these results, DOW with high magnesium levels reduced serum and liver triglyceride and cholesterol levels and serum AST and ALT activities. However, when the calcium and/or potassium minerals were removed from DOW, the effects of reduction of triglyceride level, inhibition of acetyl-CoA carboxylase (ACC), fatty acid synthase (FAS), and peroxisome proliferator-activated receptor-alpha (PPAR-α) expressions, and activation of superoxide dismutase, catalase, and glutathione reductase activities would be weaker. In conclusion, DOW including magnesium, calcium and potassium minerals has the strongest preventive effect on NAFLD in a mouse model by increasing the antioxidant system and inhibiting fatty acid biosynthesis.

Immunological mechanisms and therapeutic targets of fatty liver diseases

Alcoholic liver disease (ALD) and nonalcoholic fatty liver disease (NAFLD) are the two major types of chronic liver disease worldwide. Inflammatory processes play key roles in the pathogeneses of fatty liver diseases, and continuous inflammation promotes the progression of alcoholic steatohepatitis (ASH) and nonalcoholic steatohepatitis (NASH). Although both ALD and NAFLD are closely related to inflammation, their respective developmental mechanisms differ to some extent. Here, we review the roles of multiple immunological mechanisms and therapeutic targets related to the inflammation associated with fatty liver diseases and the differences in the progression of ASH and NASH. Multiple cell types in the liver, including macrophages, neutrophils, other immune cell types and hepatocytes, are involved in fatty liver disease inflammation. In addition, microRNAs (miRNAs), extracellular vesicles (EVs), and complement also contribute to the inflammatory process, as does intertissue crosstalk between the liver and the intestine, adipose tissue, and the nervous system. We point out that inflammation also plays important roles in promoting liver repair and controlling bacterial infections. Understanding the complex regulatory process of disrupted homeostasis during the development of fatty liver diseases may lead to the development of improved targeted therapeutic intervention strategies.

Lean NAFLD: A Distinct Entity Shaped by Differential Metabolic Adaptation

BACKGROUND AND AIMS

Nonalcoholic fatty liver disease (NAFLD) affects a quarter of the adult population. A significant subset of patients are lean, but their underlying pathophysiology is not well understood.

APPROACH AND RESULTS

We investigated the role of bile acids (BAs) and the gut microbiome in the pathogenesis of lean NAFLD. BA and fibroblast growth factor (FGF) 19 levels (a surrogate for intestinal farnesoid X receptor [FXR] activity), patatin-like phospholipase domain containing 3 (PNPLA3), and transmembrane 6 superfamily member 2 (TM6SF2) variants, and gut microbiota profiles in lean and nonlean NAFLD were investigated in a cohort of Caucasian patients with biopsy-proven NAFLD (n = 538), lean healthy controls (n = 30), and experimental murine models. Patients with lean NAFLD had a more favorable metabolic and histological profile compared with those with nonlean NAFLD (P < 0.05 for all). BA levels were significantly higher in NAFLD with advanced compared with earlier stages of liver fibrosis. Patients with lean NAFLD had higher serum secondary BA and FGF19 levels and reduced 7-alpha-hydroxy-4-cholesten-3-one (C4) levels (P < 0.05 for all). These differences were more profound in early compared with advanced stages of fibrosis (P < 0.05 for both). Lean patients demonstrated an altered gut microbiota profile. Similar findings were demonstrated in lean and nonlean murine models of NAFLD. Treating mice with an apical sodium-dependent BA transporter inhibitor (SC-435) resulted in marked increases in fgf15, a shift in the BA and microbiota profiles, and improved steatohepatitis in the lean model.

CONCLUSIONS

Differences in metabolic adaptation between patients with lean and nonlean NAFLD, at least in part, explain the pathophysiology and provide options for therapy.

Epidemiology of non-alcoholic fatty liver disease in Asia

The growing burden of non-alcoholic fatty liver disease (NAFLD) parallels the increasing prevalence of obesity in Asia. The overall prevalence of NAFLD in Asia is now estimated to be 29.6% and may have surpassed that in Western populations. NAFLD increases with increasing age and is closely associated with metabolic syndrome. Ethnic differences exist in the prevalence of NAFLD, but the underlying factors are unclear. There were initial concerns about lean NAFLD being associated with more severe liver disease and increased mortality, but subsequent studies suggested otherwise. Only some NAFLD patients progress to develop advanced liver fibrosis and cirrhosis, while the liver status remains unchanged in the majority; fibrosis stage is the most important predictor of disease-specific mortality in NAFLD. Surveillance for hepatocellular carcinoma (HCC) remains a challenge due to undiagnosed cirrhosis and the development of HCC in non-cirrhotic NAFLD patients. Diabetes mellitus shares a bidirectional relationship with NAFLD; NAFLD is highly prevalent among patients with diabetes mellitus, and diabetes mellitus is associated with more severe NAFLD. Chronic hepatitis B (CHB) is a major cause of chronic liver disease in Asia; NAFLD and CHB are increasingly observed together because of the increasing prevalence of NAFLD. Despite studies reporting favorable virologic outcome in CHB patients with NAFLD, NAFLD has been found to be independently associated with fibrosis progression and poorer prognosis in CHB patients. Therefore, NAFLD in CHB patients should be given more attention.

[Effect of epigallocatechin-3-gallate on liver lipid metabolism in rats with intrauterine growth restriction and related mechanism]

OBJECTIVE

To study the effect of epigallocatechin-3-gallate (EGCG) on liver lipid metabolism in rats with intrauterine growth restriction (IUGR) and related mechanism.

METHODS

A rat model of IUGR was established by food restriction during entire pregnancy, and then the rats were randomly divided into an IUGR group and an EGCG group (n=8 each). The rats in the EGCG group were fed with water containing EGCG from after weaning to 10 weeks. Eight pup rats born from the pregnant maternal rats without food restriction were used as the control group. At the age of 13 weeks, body weight was measured. Blood and liver tissue samples were collected to measure fasting total cholesterol (TC), triglyceride (TG), free fatty acid (FFA), fasting plasma glucose (FPG), fasting insulin (FINS), and liver lipids. Homeostasis model assessment of insulin resistance (HOMA-IR) and adipose insulin resistance (adipo-IR) were calculated. Pathological sections of the liver were observed and quantitative real-time PCR was used to measure the mRNA expression of related genes in the liver.

RESULTS

At the age of 13 weeks, there was no significant difference in body weight between groups (P=0.067). There were significant differences between groups in FPG, FFA, FINS, HOMA-IR, and adipo-IR (P<0.05). There were no significant differences in the serum levels of TC and TG between groups (P>0.05), while the IUGR group had significantly higher levels of TC and TG in the liver than the EGCG group (P<0.05). Oil red staining showed that the IUGR group had a significant increase in hepatic lipid accumulation, while the EGCG group had certain improvement after EGCG treatment. PCR results suggested that compared with the control group, the IUGR group had significant reductions in the mRNA expression of Ampk and Adipor1 and a significant increase in the mRNA expression of Srebf1 (P<0.05), while EGCG increased the mRNA expression of Ampk and reduced the mRNA expression of Srebf1, with no significant differences in the two indices between the EGCG and control groups (P>0.05).

CONCLUSIONS

Early EGCG intervention can down-regulate the de novo synthesis of fatty acids through the Ampk/Srebf1 signaling pathway and reduce hepatic lipid accumulation in IUGR rats by improving insulin resistance of hepatocytes.

Pathophysiological, Molecular and Therapeutic Issues of Nonalcoholic Fatty Liver Disease: An Overview

Nonalcoholic Fatty Liver Disease (NAFLD) represents the leading cause of liver disease in developed countries but its diffusion is currently also emerging in Asian countries, in South America and in other developing countries. It is progressively becoming one of the main diseases responsible for hepatic insufficiency, hepatocarcinoma and the need for orthotopic liver transplantation. NAFLD is linked with metabolic syndrome in a close and bidirectional relationship. To date, NAFLD is a diagnosis of exclusion, and liver biopsy is the gold standard for diagnosis. NAFLD pathogenesis is complex and multifactorial, mainly involving genetic, metabolic and environmental factors. New concepts are constantly arising in the literature promising new diagnostic and therapeutic tools. One of the challenges will be to better characterize not only NAFLD development but overall NAFLD progression, in order to better identify NAFLD patients at higher risk of metabolic, cardiovascular and neoplastic complications. This review analyses NAFLD epidemiology and the different prevalence of the disease in distinct groups, particularly according to sex, age, body mass index, type 2 diabetes and dyslipidemia. Furthermore, the work expands on the pathophysiology of NAFLD, examining multiple-hit pathogenesis and the role of different factors in hepatic steatosis development and progression: genetics, metabolic factors and insulin resistance, diet, adipose tissue, gut microbiota, iron deposits, bile acids and circadian clock. In conclusion, the current available therapies for NAFLD will be discussed.

Molecular pathways of nonalcoholic fatty liver disease development and progression

Nonalcoholic fatty liver disease (NAFLD) is a main hepatic manifestation of metabolic syndrome. It represents a wide spectrum of histopathological abnormalities ranging from simple steatosis to nonalcoholic steatohepatitis (NASH) with or without fibrosis and, eventually, cirrhosis and hepatocellular carcinoma. While hepatic simple steatosis seems to be a rather benign manifestation of hepatic triglyceride accumulation, the buildup of highly toxic free fatty acids associated with insulin resistance-induced massive free fatty acid mobilization from adipose tissue and the increased de novo hepatic fatty acid synthesis from glucose acts as the "first hit" for NAFLD development. NAFLD progression seems to involve the occurrence of "parallel, multiple-hit" injuries, such as oxidative stress-induced mitochondrial dysfunction, endoplasmic reticulum stress, endotoxin-induced, TLR4-dependent release of inflammatory cytokines, and iron overload, among many others. These deleterious factors are responsible for the triggering of a number of signaling cascades leading to inflammation, cell death, and fibrosis, the hallmarks of NASH. This review is aimed at integrating the overwhelming progress made in the characterization of the physiopathological mechanisms of NAFLD at a molecular level, to better understand the factor influencing the initiation and progression of the disease.

Pathogenesis of NASH: The Impact of Multiple Pathways

Purpose of review

Advancing our understanding of the mechanisms that underlie NASH pathogenesis.

Recent findings

Recent findings on NASH pathogenesis have expanded our understanding of its complexity including: (1) there are multiple parallel hits that lead to NASH; (2) the microbiota play an important role in pathogenesis, with bacterial species recently shown to accurately differentiate between NAFL and NASH patients; (3) the main drivers of liver cell injury are lipotoxicity caused by free fatty acids (FFAs) and their derivatives combined with mitochondrial dysfunction; (4) decreased endoplasmic reticulum (ER) efficiency with increased demand for protein synthesis/folding/repair results in ER stress, protracted unfolded protein response, and apoptosis; (5) upregulated proteins involved in multiple pathways including JNK, CHOP, PERK, BH3-only proteins, and caspases result in mitochondrial dysfunction and apoptosis; and (6) subtypes of NASH in which these pathophysiological pathways vary may require patient subtype identification to choose effective therapy.

Summary

Recent pathogenesis studies may lead to important therapeutic advances, already seen in patients treated with ACC, ASK1 and SCD1 inhibitors and FXR agonists. Further advancing our understanding of mechanisms underlying NASH pathogenesis and the complex interplay between them will be crucial for developing effective therapies.

Both alcoholic and non-alcoholic steatohepatitis association with cardiovascular risk and liver fibrosis

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) is the most common cause of liver disease worldwide. Mortality in NAFLD is mainly related to cardiovascular disease (CVD) and cancer. NAFLD and its association with both CVD and liver disease risk have been well evaluated, but the association of NAFLD with alcohol, known as "both alcoholic and non-alcoholic steatohepatitis" (BASH), remains uncertain. The objective of this study was to assess the influence of alcohol and obesity in the development of liver and cardiovascular disease risk.

METHODS

This was a case-control study that included patients from a regular check-up. Alcohol consumption was evaluated with MAST, AUDIT, and CAGE. Cardiovascular risk was evaluated using the Framingham score, and liver fibrosis was evaluated with APRI and NAFLD score. Patients were classified in five groups: healthy patients, steatosis with obesity, steatosis with alcoholism, BASH, and idiopathic steatosis.

RESULTS

A total of 414 patients were included. The BASH group represented 16% of patients, and showed a greater proportion of patients with high cardiovascular risk with 17% (p = 0.001), and liver fibrosis with 9%, according to the APRI score (p = 0.10). A multivariate logistic regression showed that alcohol consumption >140 g/week (OR 2.546, 95% CI 1.11-5.81, p = 0.003) and BMI >25 kg/m² (OR 12.64, 95% CI 1.66 96.20, p = 0.001) were related to high cardiovascular risk. Liver fibrosis according to APRI was only related to alcohol consumption >140 g/week (OR 2.74, 95% CI 1-7.48, p = 0.03).

CONCLUSIONS

BASH remains an area not well explored, and of great implication given the increasing number of patients affected. We observed an additive effect of both etiologies in the development of high cardiovascular and liver disease risk.

Evaluation of high-fat high-fructose diet treatment in factor VIII (coagulation factor)-deficient mouse model

Non-alcoholic fatty liver disease (NAFLD)-like conditions enhance the production and action of clotting factors in humans. However, studies examining the effect of NAFLD due to high-fat high-fructose (HFHF) diet in factor VIII-deficient (haemophilia A) animals or patients have not been reported previously. In this study, we investigated the individual role of factor VIII in the progression of diet-induced NAFLD in the factor 8^-/- (F8^-/- ) mouse model system and its consequences on the haemophilic status of the mice. The F8^-/- mice were fed with HFHF diet for 14 weeks. Physiological, biochemical, haematological, molecular, pathological, and immune histochemical analyses were performed to evaluate the effect of this diet. The F8^-/- mice developed hepatic steatosis after 14 weeks HFHF diet and displayed lower energy metabolism, higher myeloid cell infiltration in the liver, decreased platelet count, upregulated de novo fatty acid synthesis, lipid accumulation, and collagen deposition. This study helps to understand the role of factor VIII in NAFLD pathogenesis and to analyse the severity and consequences of steatosis in haemophilic patients as compared to normal population. This study suggests that haemophilic animals (F8^-/- mice) are highly prone to hepatic steatosis and thrombocytopenia.

Bile acid detoxifying enzymes limit susceptibility to liver fibrosis in female SHRSP5/Dmcr rats fed with a high-fat-cholesterol diet

During middle age, women are less susceptible to nonalcoholic steatohepatitis (NASH) than men. Thus, we investigated the underlying molecular mechanisms behind these sexual differences using an established rat model of NASH. Mature female and male stroke-prone spontaneously hypertensive 5/Dmcr rats were fed control or high-fat-cholesterol (HFC) diets for 2, 8, and 14 weeks. Although HFC-induced hepatic fibrosis was markedly less severe in females than in males, only minor gender differences were observed in expression levels of cytochrome P450 enzymes (CYP)7A1, CYP8B1 CYP27A1, and CYP7B1, and multidrug resistance-associated protein 3, and bile salt export pump, which are involved in fibrosis-related bile acid (BA) kinetics. However, the BA detoxification-related enzymes UDP-glucuronosyltransferase (UGT) and sulfotransferase (SULT) 2A1, and the nuclear receptors constitutive androstane receptor (CAR) and pregnane X receptor (PXR), were strongly suppressed in HFC-fed males, and were only slightly changed in HFC-diet fed females. Expression levels of the farnesoid X receptor and its small heterodimer partner were similarly regulated in a gender-dependent fashion following HFC feeding. Hence, the pronounced female resistance to HFC-induced liver damage likely reflects sustained expression of the nuclear receptors CAR and PXR and the BA detoxification enzymes UGT and SULT.

Current Treatment of Nonalcoholic Fatty Liver Disease/Nonalcoholic Steatohepatitis

Treatment of nonalcoholic fatty liver disease (NAFLD)/nonalcoholic steatohepatitis (NASH) is focused on patients with NASH because they are at highest risk for progressive liver disease. Current first-line treatment consists of lifestyle modifications. Patients should lose at least 7% to 10% of body weight via a combination of physical exercise and calorie restriction dieting. Surgical or endoscopic surgery for weight loss can be considered in obese patients, depending on degree of excess body weight and comorbidities. There is no currently approved pharmacotherapy for NASH. Vitamin E and pioglitazone have the most evidence of therapeutic efficacy but have limitations. The treatment modality chosen should be individualized.

Non-alcoholic Fatty Liver Disease in Lean Subjects: Characteristics and Implications

Non-alcoholic fatty liver disease (NAFLD) is commonly diagnosed in obese subjects; however, it is not rare among lean individuals. Given the absence of traditional risk factors, it tends to remain under-recognised. The metabolic profiles of lean NAFLD patients are frequently comparable to those of obese NAFLD patients. Though results from several studies have been mixed, it has been generally revealed that lean subjects with NAFLD have minor insulin resistance compared to that in obese NAFLD. Several genetic variants are associated with NAFLD without insulin resistance. Some data suggest that the prevalence of steatohepatitis and advanced fibrosis do not differ significantly between lean and obese NAFLD; however, the former tend to have less severe disease at presentation. The underlying pathophysiology of lean NAFLD may be quite different. Genetic predispositions, fructose- and cholesterol-rich diet, visceral adiposity and dyslipidaemia have potential roles in the pathogenic underpinnings. Lean NAFLD may pose a risk for metabolic disturbances, cardiovascular morbidity or overall mortality. Secondary causes of hepatic steatosis are also needed to be ruled out in lean subjects with NAFLD. The effectiveness of various treatment modalities, such as exercise and pharmacotherapy, on lean NAFLD is not known. Weight loss is expected to help lean NAFLD patients who have visceral obesity. Further investigation is needed for many aspects of lean NAFLD, including mechanistic pathogenesis, risk assessment, natural history and therapeutic approach.

Targeting Sirt1 in a rat model of high-fat diet-induced non-alcoholic fatty liver disease: Comparison of Gegen Qinlian decoction and resveratrol

The present study aimed to explore the mechanism of action of Gegen Qinlian decoction (GGQLD) in experimental non-alcoholic fatty liver disease (NAFLD). A total of 30 rats were randomly divided into five groups: The chow, model, high- and low-dose GGQLD (GGQLD-H and GGQLD-L, respectively) and resveratrol (Resl) groups, and were treated with saline, GGQLD and Resl when a model of high-fat diet (HFD)-induced NAFLD was established. Blood lipid and liver enzymes were detected following treatment for 8 weeks and liver tissue pathology was observed using Oil Red O and haematoxylin and eosin staining. Furthermore, the liver protein and mRNA expression of sirtuin (Sirt)1, peroxisome proliferator-activated receptor-γ coactivator (PGC)-1α and nuclear factor κ-light-chain-enhancer of activated B cells (NF-κB) were measured using western blotting and reverse transcription-quantitative polymerase chain reaction. Compared with the chow group, the model group demonstrated significantly increased serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels (P<0.01). GGQLD doses and Resl attenuated the elevated serum ALT and AST levels. GGQLD-H and Resl significantly increased the serum high-density lipoprotein cholesterol level compared with that in the model group (P<0.01), while GGQLD-L and Resl significantly decreased serum low-density lipoprotein cholesterol levels (P<0.01). The GGQLDs and Resl groups revealed an evident improvement in Sirt1 protein and mRNA expression. Although GGQLD and Resl significantly decreased NF-κB gene expression compared with the model group (P<0.01), the effect on NF-κB protein expression was not significant. Furthermore, the PGC-1α gene and protein expression in the HFD rat group slightly decreased compared to the levels in the chow group, but the decrease was insignificant. However, an evident increase in PGC-1α mRNA expression was observed in the GGQLD-H group compared with the model group (P<0.01). Histological staining revealed that GGQLD and Resl decreased the lipid droplets in hepatocytes and normalized steatosis in rats fed with a HFD. The results indicated that GGQLD treatment may be a potent strategy for managing NAFLD by managing lipid metabolism and inflammatory and histological abnormalities by triggering the Sirt1 pathway.

Yinchen Linggui Zhugan Decoction Ameliorates Nonalcoholic Fatty Liver Disease in Rats by Regulating the Nrf2/ARE Signaling Pathway

Yinchen Linggui Zhugan Decoction (YCLGZGD) is the combination of Linggui Zhugan (LGZGD) and Yinchenhao (YCHD) decoctions, two famous traditional Chinese medicine prescriptions. In previous studies, we found that Yinchen Linggui Zhugan Decoction (YCLGZGD) could regulate lipid metabolism disorder and attenuate inflammation in pathological process of nonalcoholic fatty liver disease (NAFLD). However, the exact underlying mechanism remains unknown. The aim of this study was to explore the effect of Yinchen Linggui Zhugan Decoction on experimental NAFLD and its mechanism in rats with high-fat diet (HFD) which was established by 8-week administration of HFD. YCLGZGD, LGZGD, and YCHD were administered daily for 4 weeks, after which the rats were euthanized. The level of blood lipid, liver enzymes, H&E, and Oil Red O staining were determined to evaluate NAFLD severity. Western blotting and real-time polymerase chain reaction were, respectively, used to determine hepatic protein and gene expression of Keap1, Nrf2, NQO1, and HO-1. Oral YCLGZGD ameliorated HFD-induced NAFLD. Furthermore, YCLGZGD increased the protein and gene expression of Nrf2, NQO1, and HO-1 without changing Keap1. Overall, these results suggest that YCLGZGD ameliorates HFD-induced NAFLD in rats by upregulating the Nrf2/ARE signaling pathway.

Nonobese Fatty Liver Disease

Nonalcoholic fatty liver disease (NAFLD) refers to a group of conditions characterized by hepatic steatosis in the absence of significant alcohol consumption. NAFLD is seen commonly in patients with metabolic abnormalities associated with obesity, such as type II diabetes, dyslipidemia, and metabolic syndrome. Evidently, however, not all obese subjects develop NAFLD and, more importantly, NAFLD can be found in nonobese individuals. Although NAFLD occurring in nonobese subjects has been reported in children and adults of all ethnicities, it appears to be recognized more frequently in Asians, even when strict ethnicity-specific body mass index criteria are used to define obesity. Studies based on liver biopsies suggest that the prevalence of nonalcoholic steatohepatitis and fibrosis does not differ significantly between nonobese NAFLD and NAFLD in obese patients. Visceral obesity as opposed to general obesity, high fructose and cholesterol intake, and genetic risk factors (eg, palatin-like phospholipase domain-containing 3) may be associated with nonobese NAFLD. In general, nonalcoholic steatohepatitis is associated with increased mortality, primarily from cardiovascular causes, independent of other metabolic factors. Although data regarding the mortality impact of nonobese NAFLD are not as mature, it may be important to identify high-risk nonobese NAFLD patients and manage their metabolic profile. Currently, lifestyle modification to reduce visceral adiposity, including dietary changes and physical activity, remains the standard of care in patients with nonobese NAFLD.

The effect of cannabinoid receptor 1 blockade on hepatic free fatty acid profile in mice with nonalcoholic fatty liver disease

We used rimonabant to investigate the role of CB1 receptor on hepatic FFAs profile during NAFLD. Male mice C57BL/6 were divided into: control group fed with control diet 20 weeks (C; n=6); group fed with HFD 20 weeks (HF; n=6); group fed with control diet and treated with rimonabant after 18 weeks (R; n=9); group fed with HFD and treated with rimonabant after 18 weeks (HFR; n=10). Rimonabant (10mg/kg) was administered daily to HFR and R group by oral gavage. Rimonabant decreased liver palmitic acid proportion in HFR group compared to HF group (p<0.05). Liver stearic and oleic acid proportions were decreased in R group compared to control (p<0.01 respectively). Rimonabant increased liver linoleic and arachidonic acid proportions in HFR group compared to HF group (p<0.01 respectively). CB1 blockade may be useful in the treatment of HFD-induced NAFLD due to modulation of plasma lipid and hepatic FFA profile.

Phytosterol esters attenuate hepatic steatosis in rats with non-alcoholic fatty liver disease rats fed a high-fat diet

Given the adverse effects of drugs used for NAFLD treatment, identifying novel and effective natural compound to prevent NAFLD is urgently needed. In the present study, the effects of phytosterol esters (PSEs) on NAFLD were explored. Adult SD rats were randomized into five groups: normal chow diet (NC), high-fat diet (HF), low-, medium- and high-dose PSE treatment plus high-fat diet groups (PSEL, PSEM, and PSEH). Our results showed that the levels of LDL-C in the PSEL group and hepatic TG, TC, and FFA in the three PSEs groups were significantly decreased. Notably, the uric acid (UA) level was significantly decreased by PSEs intervention. The hepatic inflammatory stress was ameliorated via the inhibition of the cytokines, including TGF-β, IL-6, IL-10 and CRP in the PSEs intervention groups. Further, the oxidative status was improved by PSE treatment through adjusting the enzyme activity (SOD and XOD) and decreasing the MDA level. These beneficial effects of PSE may have been partly due to its regulation on the expression of TGF-β1, TGF-β2, TNF-α, UCP-2, PPAR-α and PPAR-γ in hepatic tissue at both mRNA and protein level. The results of this study suggest that PSEs may be used as therapeutic agents for the prevention and progression of NAFLD and that hyperuricemia is induced by high-fat diet consumption.

Effect of defatted pepper (Capsicum annuum L.) seed extracts on high-fat diet-induced obesity in C57BL/6J mice

This study investigated the effect of defatted pepper seed ethanolic extract (DPSE) on high-fat diet-induced obesity in C57BL/6J mice. The mice were fed a normal diet (ND), high fat diet (HFD), or HFD in combination with DPSE (100 and 200mg/kg body weight) for 7 weeks. Supplementing the HFD of mice with DPSE significantly decreased body weight gain and food efficiency ratio induced by HFD. The amount of epididymal fat and size of adipocytes were also dramatically reduced by DPSE supplementation. Although no statistical significance was found between the HFD and HFD plus DPSE groups in plasma fat deposition, liver weight, and hepatic cholesterol contents were significantly reduced in the DPSE-treated group. In conclusion, these results suggest that DPSE could prevent obesity and adiposity. These effects may be important in developing therapeutic agents against obesity in future.

Mulberry leaves (Morus alba L.) ameliorate obesity-induced hepatic lipogenesis, fibrosis, and oxidative stress in high-fat diet-fed mice

Obesity is associated with chronic diseases such as fatty liver, type 2 diabetes, cardiovascular disease, and severe metabolic syndrome. Obesity causes metabolic impairment including excessive lipid accumulation and fibrosis in the hepatic tissue as well as the increase in oxidative stress. In order to investigate the effect of mulberry leaf (Morus alba L.) extract (MLE) on obesity-induced oxidative stress, lipogenesis, and fibrosis in liver, MLE has been gavaged for 12 weeks in high-fat diet (HFD)-induced obese mice. MLE treatment significantly ameliorated LXRα-mediated lipogenesis and hepatic fibrosis markers such as α-smooth muscle actin, while MLE up-regulated lipolysis-associated markers such as lipoprotein lipase in the HFD-fed mice. Moreover, MLE normalized the activities of antioxidant enzymes including heme oxygenase-1 and glutathione peroxidase in accordance with protein levels of 4-hydroxynonenal in the HFD-fed mice. MLE has beneficial effects on obesity-related fatty liver disease by regulation of hepatic lipid metabolism, fibrosis, and antioxidant defense system. MLE supplementation might be a potential therapeutic approach for obesity-related disease including non-alcoholic fatty liver disease.

Intervening TNF-α via PPARγ with Gegenqinlian Decoction in Experimental Nonalcoholic Fatty Liver Disease

This paper is to explore the effect and mechanism of Gegenqinlian decoction on experimental nonalcoholic fatty liver disease (NAFLD) in vivo and in vitro. The final aim is to make clear whether Gegenqinlian decoction would impact NAFLD through improving PPARγ to suppress inflammation and regulate lipid. The data in this research suggested that Gegenqinlian decoction is a potent way to manage NAFLD through improving PPARγ to regulate lipid and suppress inflammation.

Differential effects of habitual chow-based and semi-purified diets on lipid metabolism in lactating rats and their offspring

Diet during pregnancy and lactation is a critical factor in relation to the health of dams and their offspring. Currently, control diets used in metabolic imprinting studies differ in composition and type, i.e. semi-purified diets (SD) or chow-based diets (ND). The aim of the present study was to determine whether two widely used control diets, a SD and a ND, that mainly differ in fat content (5·08 and 3·26 %, respectively) and its sources (soyabean oil for the SD and cereals and fish for the ND), fibre (6 and 15 %, respectively), and cholesterol (26 and 69 mg/kg diet, respectively) can influence the lipid metabolism of dams and their offspring. Wistar rats were fed either the SD or the ND during pregnancy and lactation. At weaning, SD-fed dams presented severe hepatic steatosis and increased levels of circulating TAG, NEFA and insulin. Importantly, the offspring presented an altered plasma lipid profile. In contrast, the ND allowed for a normal gestation and lactation process, and did not affect the metabolism of offspring. In parallel, virgin rats fed the SD showed no metabolic alterations. A higher intake of SFA and MUFA and a lower consumption of PUFA observed in SD-fed dams during the lactation period could contribute to explaining the observed effects. In conclusion, two different control diets produced very different outcomes in the lipid metabolism of lactating rats and their offspring. The present results highlight the importance of the assessment of the metabolic state of dams when interpreting the results of metabolic programming studies.

Expression of miRNA-21 and Smad7 in arsenic-induced hepatic fibrosis in rats: Possible mechanism of traditional Chinese herbs for preventing hepatic fibrosis

AIM: To investigate the expression of microRNA (miRNA)-21 and Smad7 in arsenic-induced hepatic fibrosis in rats and to explore the possible mechanism of Danshao Huaxian capsule for preventing arsenic-induced hepatic fibrosis.

METHODS: Seventy-five male SD rats were randomly divided into a control group (A), an arsenic exposure group (B), a Fuzheng Huayu capsule group (C), low- (D) and high-dose (E) Danshao Haxian capsule groups (n = 15 for each). Rats in group A were given tap water, while rats in groups B-E were given 100 mg/L NaAsO₂ solution. Moreover, rats in groups C-E were respectively administered by gastrogavage with Fuzheng Huayu capsule (0.8 g/kg) or Danshao Haxian capsule (0.5, 1.0 g/kg), twice per day, 5 d/wk for 16 wk. By the end of the experiment, alanine transaminase (ALT) and aspartate transaminase (AST) in serum were measured with an automatic biochemical analyzer, and levels of hyaluronic acid (HA) and transforming growth factor (TGF)-β1 in liver homogenates were determined by ELISA. Histological changes in the liver were observed after HE and Masson's trichrome staining. The expression of miRNA-21 in liver tissue was determined by RT-PCR. The mRNA and protein expression of Smad7 in liver tissue was determined by RT-PCR, immunohistochemistry, and Western blot analysis.

RESULTS: Compared with group A, serum activities of ALT and AST, levels of HA and TGF-β1 in liver homogenates were significantly increased in groups B-E, but these indices were significantly lower in groups C-E compared with group B (F = 129.159, 291.878, 5316.239, 1269.287, P < 0.01). Obvious proliferation and widened collagen fibers were seen in liver tissues of group B rats, while the degree of hepatic fibrosis was significantly milder in groups C-E than in group B (F = 62.832, 68.112, P < 0.05 or P < 0.01). Compared with group A, the expression of miRNA-21 was significantly higher in groups B-E, but it was significantly lower in groups C-E than in group B (F = 552.231, P < 0.01). Compared with group A, the mRNA and protein expression of Smad7 was significantly lower in groups B-E, but the expression was significantly higher in groups C-E than in group B (F = 129.512, 68.249, 43.435, P < 0.05 or P < 0.01).

CONCLUSION: Oral arsenic solution for 16 wk induced obvious hepatic fibrosis in rats, partly by up-regulating miRNA-21 and down-regulating Smad7 expression. The mechanism of Danshao Haxian capsule for preventing hepatic fibrosis in rats may be associated with inhibition of the expression of miRNA-21 and up-regulation of the expression of Smad7.

Preventive effects of phytosterol ester on high fat diet-induced non-alcoholic fatty liver disease in rats

AIM: To explore the preventive effects of phytosterol ester (PSE) on high fat diet-induced non-alcoholic fatty liver disease (NAFLD).

METHODS: An NAFLD rat model was established by giving a high fat diet, and different dosages of PSE [PSE_L: 0.05 g/100 g body weight (BW); PSE_M: 0.10 g/100 g BW; PSE_H: 0.15 g/100 g BW] fortified milk were given to rats by intragastric administration. Serum lipid profile and liver lipids were detected, and histological changes were observed after HE staining.

RESULTS: Compared with the high fat diet group (HF group), serum low-density lipoprotein cholesterol (LDL-C) in animals in the PSE_L group was lowered by 13.6%, while no further effect was observed with higher concentrations of PSE; liver triglyceride (TG), total cholesterol (TC), and free fatty acids (FFAs) were reduced significantly in all the PSE treatment groups, among which the level of FFA was close to the normal level. Glucose (GLU) levels in the PSE_M and PSE_H groups were lower than that in the HF group, which were close to the normal level. HE staining results showed that the degree of hepatic steatosis was obviously ameliorated in all the PSE treatment groups.

CONCLUSION: PSE could effectively reduce serum LDL-C and hepatic fat accumulation induced by a high fat diet, and attenuate hepatic steatosis, thus exhibiting preventive effects on NAFLD.

4Ps medicine of the fatty liver: the research model of predictive, preventive, personalized and participatory medicine-recommendations for facing obesity, fatty liver and fibrosis epidemics

Relationship between adipose tissue and fatty liver, and its possible evolution in fibrosis, is supported by clinical and research experience. Given the multifactorial pathogenesis of non-alcoholic fatty liver disease (NAFLD), treatments for various contributory risk factors have been proposed; however, there is no single validated therapy or drug association recommended for all cases which can stand alone. Mechanisms, diagnostics, prevention and treatment of obesity, fatty liver and insulin resistance are displayed along with recommendations and position points. Evidences and practice can get sustainable and cost-benefit valuable outcomes by participatory interventions. These recommendations can be enhanced by comprehensive research projects, addressed to societal issues and innovation, market appeal and industry development, cultural acceptance and sustainability. The basis of participatory medicine is a greater widespread awareness of a condition which is both a disease and an easy documented and inclusive clue for associated diseases and unhealthy lifestyle. This model is suitable for addressing prevention and useful for monitoring improvement, worsening and adherence with non-invasive imaging tools which allow targeted approaches. The latter include health psychology and nutritional and physical exercise prescription expertise disseminated by continuous medical education but, more important, by concrete curricula for training undergraduate and postgraduate students. It is possible and recommended to do it by early formal teaching of ultrasound imaging procedures and of practical lifestyle intervention strategies, including approaches aimed to healthier fashion suggestions. Guidelines and requirements of research project funding calls should be addressed also to NAFLD and allied conditions and should encompass the goal of training by research and the inclusion of participatory medicine topics. A deeper awareness of ethics of competences in health professionals and the articulation of knowledge, expertise and skills of medical doctors, dieticians, health psychologists and sport and physical exercise graduates are the necessary strategy for detectin a suboptimal health status and achieving realistically beneficial lifestyle changes. “The devil has put a penalty on all things we enjoy in life. Either we suffer in health or we suffer in soul or we get fat” (Albert Einstein); the task of medical research and intervention is to make possible to enjoy life also without things that make sufferance in health and souls and which excessively increase body fat.

Reduced oxidative stress contributes to the lipid lowering effects of isoquercitrin in free fatty acids induced hepatocytes

Oxidative stress interferes with hepatic lipid metabolism at various levels ranging from benign lipid storage to so-called second hit of inflammation activation. Isoquercitrin (IQ) is widely present flavonoid but its effects on hepatic lipid metabolism remain unknown. We used free fatty acids (FFA) induced lipid overload and oxidative stress model in two types of liver cells and measured cell viability, intracellular lipids, and reactive oxygen species (ROS) within hepatocytes. In addition, Intracellular triglycerides (TG), superoxide dismutase (SOD), and malondialdehyde (MDA) were examined. A novel in vitro model was used to evaluate correlation between lipid lowering and antioxidative activities. Furthermore, 34 major cytokines and corresponding ROS levels were analyzed in FFA/LPS induced coculture model between hepatocytes and Kupffer cells. At molecular level AMPK pathway was elucidated. We showed that IQ attenuated FFA induced lipid overload and ROS within hepatocytes. Further, IQ reversed FFA induced increase in intracellular TG SOD and MDA. It was shown that antioxidative activity of IQ correlates with its lipid lowering potentials. IQ reversed major proinflammatory cytokines and oxidative stress in FFA/LPS induced coculture model. Finally, AMPK pathway was found responsible for metabolic benefits at molecular level. IQ strikingly manifests antioxidative and related lipid lowering activities in hepatocytes.

Recent insights into farnesoid X receptor in non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD) is the hepatic manifestation of metabolic syndrome and is one of the most prevalent liver disorders worldwide. NAFLD can gradually progress to liver inflammation, fibrosis, cirrhosis and even hepatocellular carcinoma. However, the pathogenesis of NAFLD is complex, and no efficient pharmaceutic treatments have yet been established for NAFLD. Accumulating data have shown that the farnesoid X receptor (FXR) plays important roles not only in bile acid metabolism, but also in lipid and carbohydrate homeostasis, inflammatory responses, among others. In this review, we aim to highlight the role of FXR in the pathogenesis and treatment of NAFLD.

Long-term intake of soyabean phytosterols lowers serum TAG and NEFA concentrations, increases bile acid synthesis and protects against fatty liver development in dyslipidaemic hamsters

Various human trials and pre-clinical studies have suggested that dietary plant sterols possess hypotriacylglycerolaemic properties apart from their cholesterol-lowering properties. We hypothesised that phytosterols (PS) might attenuate triacylglycerolaemia by interfering with the deleterious effects of cholesterol overload in the liver. In the present study, twenty hamsters (Mesocricetus auratus) with diet-induced combined hyperlipidaemia were fed a high-fat diet (HFD, n 10) or a HFD supplemented with soyabean PS (n 10) for 40 d. In parallel, a healthy group was fed a standard diet (n 10). PS normalised fasting plasma cholesterol concentrations completely after 20 d and were also able to normalise serum TAG and NEFA concentrations after 40 d. HFD feeding caused microvesicular steatosis and impaired the expression of key genes related to fatty acid oxidation such as PPARA, carnitine palmitoyltransferase-Iα (CPT1A) and phosphoenolpyruvate carboxykinase 1 (PCK1) in the liver. PS treatment completely protected against HFD-induced steatosis and resulted in a normalised hepatic gene expression profile. The protection of the hepatic function by PS was paralleled by increased faecal cholesterol excretion along with a 2-fold increase in the biliary bile acid (BA):cholesterol ratio. The present study supports the conclusion that long-term consumption of PS can reduce serum TAG and NEFA concentrations and can protect against the development of fatty liver via different mechanisms, including the enhancement of BA synthesis. The results of the present study place these compounds as promising hepatoprotective agents against fatty liver and its derived pathologies.

Non-high-density lipoprotein cholesterol independently predicts new onset of non-alcoholic fatty liver disease

BACKGROUND & AIMS

Non-alcoholic fatty liver disease (NAFLD) is associated with increased cardiovascular disease (CVD) risk. Non-high-density lipoprotein cholesterol (non-HDL-C), i.e. total cholesterol minus HDL, is a well-established risk factor for CVD; however, its association with NAFLD development has not been established. Our aim was to test whether non-HDL-C is an independent predictor of new onset of NAFLD.

METHODS

A prospective cohort study of 213 subjects from the general population, without liver disease, was studied. Evaluation of medical history, dietary and physical activity habits, fasting blood tests and ultrasonographic evidence of NAFLD was performed at baseline and after a 7-year follow-up by identical protocols.

RESULTS

From 147 patients that did not have NAFLD at baseline, 28 (19%) developed NAFLD at the 7-year follow-up. The baseline levels of non-HDL-C were higher among subjects who developed NAFLD (179.5 ± 37.1 vs. 157.3 ± 35.1 mg/dl, P = 0.003). Non-HDL-C independently predicted new onset of NAFLD adjusting for age, gender, BMI or waist circumference, lifestyle and serum insulin (OR = 1.02 for every mg/dl increment, 1.01-1.04 95% CI, P = 0.008). Non-HDL-C was a stronger predictor for NAFLD than total cholesterol, low-density lipoprotein cholesterol, triglycerides and HDL. No patients with non-HDL-C < 130 mg/dl developed NAFLD, whereas 20.8% of those with values between 130 to 160 and 24.6% of those with values >160 mg/dl developed NAFLD (P for trend = 0.015).

CONCLUSIONS

Non-HDL-C is an independent predictor for NAFLD and a stronger predictor than other lipoproteins. This association may stem from the combined hepato-toxic effect of non-HDL-C and may explain the association between NAFLD and CVD.

Dietary habits and behaviors associated with nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) is one of the most frequent causes of health problems in Western (industrialized) countries. Moreover, the incidence of infantile NAFLD is increasing, with some of these patients progressing to nonalcoholic steatohepatitis. These trends depend on dietary habits and life-style. In particular, overeating and its associated obesity affect the development of NAFLD. Nutritional problems in patients with NAFLD include excess intake of energy, carbohydrates, and lipids, and shortages of polyunsaturated fatty acids, vitamins, and minerals. Although nutritional therapeutic approaches are required for prophylaxis and treatment of NAFLD, continuous nutrition therapy is difficult for many patients because of their dietary habits and lifestyle, and because the motivation for treatment differs among patients. Thus, it is necessary to assess the nutritional background and to identify nutritional problems in each patient with NAFLD. When assessing dietary habits, it is important to individually evaluate those that are consumed excessively or insufficiently, as well as inappropriate eating behaviors. Successful nutrition therapy requires patient education, based on assessments of individual nutrients, and continuing the treatment. In this article, we update knowledge about NAFLD, review the important aspects of nutritional assessment targeting treatment success, and present some concrete nutritional care plans which can be applied generally.

Dysregulated bile acid synthesis, metabolism and excretion in a high fat-cholesterol diet-induced fibrotic steatohepatitis in rats

BACKGROUND AND AIMS

Cholesterol over-intake is involved in the onset of nonalcoholic steatohepatitis (NASH), and hepatocellular bile acid (BA) accumulation correlates with liver injuries. However, how dietary cholesterol influences cholesterol and BA kinetics in NASH liver remains ambiguous and needs to be clarified.

METHODS

Molecular markers involved in cholesterol and BA kinetics were investigated at protein and mRNA levels in an already-established stroke-prone spontaneously hypertensive 5/Dmcr rat model with fibrotic steatohepatitis, by feeding a high fat-cholesterol (HFC) diet.

RESULTS

Unlike the control diet, the HFC diet deposited cholesterol greatly in rat livers, where 3-hydroxy-3-methylglutaryl CoA reductase, low-density lipoprotein (LDL) receptor and LDL receptor-related protein-1 were expectedly downregulated, especially at 8 and 14 weeks, suggesting that cholesterol synthesis and uptake in response to cholesterol accumulation may not be disorganized. The HFC diet did not upregulate liver X receptor-α, conversely, it enhanced classic BA synthesis by upregulating cholesterol 7α-hydroxylase but downregulating sterol 12α-hydroxylase, and influenced alternative synthesis by downregulating sterol 27-hydroxylase but upregulating oxysterol 7α-hydroxylase, mainly at 8 and 14 weeks, indicating that there were different productions of primary BA species. Unexpectedly, no feedback inhibition of BA synthesis by farnesoid X receptor occurred. Additionally, the HFC diet impaired BA detoxification by UDP-glucuronosyltransferase and sulfotransferase 2A1, and decreased excretion by bile salt export pump at 8 and 14 weeks, although it induced compensatory export by multidrug resistance-associated protein-3. The disturbed BA detoxification may correlate with suppressed pregnane X receptor and constitutive androstane receptor.

CONCLUSIONS

The HFC diet may accumulate BA in rat livers, which influences fibrotic steatohepatitis progression.

Non-alcoholic fatty liver disease and obesity: not all about body mass index

Patients with nonalcoholic fatty liver (NAFLD) are typically obese and confounded by the metabolic syndrome. The body mass index (BMI) is often used as a surrogate marker of obesity defined as a BMI >30 λkg/m(2). However, it is now apparent that it is the distribution of body fat (not total fat) that is associated with NAFLD. Many patients (as many as 25%) with NAFLD are nonobese. This is particularly true in Asians who have a significantly increased risk of cardiovascular disease and diabetes even among those with a normal BMI. It is important for clinicians to be aware that these "metabolically obese" NAFLD patients should be monitored for the metabolic syndrome and its associated adverse outcomes irrespective of their BMI.

Metabolic disorders and steatosis in patients with chronic hepatitis C: metabolic strategies for antiviral treatments

It has been reported that hepatitis C virus (HCV) infection is closely associated with hepatic metabolic disorders. Hepatic steatosis and insulin resistance are both relatively common in patients with chronic hepatitis C. Recent investigations suggest that HCV infection changes the expression profile of lipid-metabolism-associated factors in the liver, conferring advantages to the life cycle of HCV. Moreover, insulin resistance and steatosis are independent predictors of impaired response to antiviral treatment in chronic hepatitis C. In this paper, we summarize our current knowledge of hepatic metabolic disorders and describe how HCV leads to and exploits these hepatic disorders. We also discuss the clinical significance of insulin sensitizers used to improve insulin resistance and lipid modulators used to manage lipid metabolism as potential treatment options for chronic hepatitis C.