Lipid metabolism and liver inflammation. II. Fatty liver disease and fatty acid oxidation

Essential Amino Acid Supplement Lowers Intrahepatic Lipid despite Excess Alcohol Consumption

Excess alcohol consumption is a top risk factor for death and disability. Fatty liver will likely develop and the risk of liver disease increases. We have previously demonstrated that an essential amino acid supplement (EAAS) improved protein synthesis and reduced intrahepatic lipid in the elderly. The purpose of this exploratory pilot study was to initiate the evaluation of EAAS on intrahepatic lipid (IHL), body composition, and blood lipids in individuals with mild to moderate alcohol use disorder (AUD). Following consent, determination of eligibility, and medical screening, 25 participants (18 males at 38 ± 15 years/age and 7 females at 34 ± 18 years/age) were enrolled and randomly assigned to one of two dosages: a low dose (LD: 8 g of EAAS twice/day (BID)) or high dose (HD: 13 g of EAAS BID). Five of the twenty-five enrolled participants dropped out of the intervention. Both groups consumed the supplement BID for 4 weeks. Pre- and post-EAAS administration, IHL was determined using magnetic resonance imaging/spectroscopy, body composition was analyzed using dual-energy X-ray absorptiometry, and blood parameters were measured by LabCorp. T-tests were used for statistical analysis and considered significant at p < 0.05. While there was no significant change in IHL in the LD group, there was a significant 23% reduction in IHL in the HD group (p = 0.02). Fat mass, lean tissue mass, bone mineral content, and blood lipids were not altered. Post-EAAS phosphatidylethanol was elevated and remained unchanged in LD at 407 ± 141 ng/mL and HD at 429 ± 196 ng/mL, indicating chronic and excess alcohol consumption. The HD of the proprietary EAAS formulation consumed BID seemed to lower IHL in individuals with mild to moderate AUD. We suggest that further studies in a larger cohort be conducted to more completely address this important area of investigation.

Effects of Phytosterol Ester on the Fatty Acid Profiles in Rats with Nonalcoholic Fatty Liver Disease

Both serum and hepatic fatty acid (FA) compositions differ among nonalcoholic hepatic steatosis, nonalcoholic steatohepatitis, and healthy subjects. The severity of the above liver disease is closely associated with the concentration and composition of FAs. Our previous study found that phytosterol ester (PSE) could alleviate hepatic steatosis in nonalcoholic fatty liver disease rats. The aims of this work were to explore the effects of PSE (0.05/100 g·body weight) on FA profiles and the mRNA levels of FA metabolism-related genes. Compared with a high-fat diet alone group, PSE treatment significantly decreased hepatic saturated fatty acid levels (P < .05) and increased monounsaturated fatty acid (especially C16:1 n-7) levels in the liver, serum, and adipose tissue and polyunsaturated fatty acid levels in the serum and liver (P < .05) after 12 weeks of intervention. In particular, PSE treatment increased the level of C22:5 n-3, an FA that was negatively correlated with the degree of hepatic steatosis in the serum, liver, and adipose tissue. The increases in some unsaturated fatty acids are probably related to the upregulation of stearoyl-coenzyme A desaturase-1 and fatty acid desaturase-1.

Granulocyte Colony Stimulating Factor Ameliorates Hepatic Steatosis Associated with Improvement of Autophagy in Diabetic Rats

BACKGROUND

We previously reported that the granulocyte colony stimulating factor (G-CSF) ameliorated hepatic steatosis with the enhancement of β-oxidation-related gene expression. However, the mechanisms underlying this process remain unclear. This study aimed to determine whether the improvement of hepatic steatosis by G-CSF was associated with autophagy in a rat model of diabetes.

METHODS

Eight rats were fed a standard diet, and 16 rats were fed high-fat diet (HFD) for 5 weeks. All HFD-fed rats were then injected with streptozotocin (STZ). One week later, HFD rats injected with STZ were randomly treated with either G-CSF (200 μg/kg/day; diabetes mellitus (DM)/G-CSF) or saline (DM/saline) for 5 consecutive days. Four weeks later, serum biochemical and histology analyses were conducted. The expression of autophagy-associated proteins was determined by Western blotting. The mRNA expression of β-oxidation-related genes was determined by quantitative real-time polymerase chain reaction. HepG2 cells were cultured under high glucose (HG) conditions with G-CSF treatment, followed by Oil Red O staining for quantification of lipids.

RESULTS

Histological analysis showed lower lipid accumulation in the DM/G-CSF group than in the DM/saline-treated rats. Protein levels of LC3 and beclin-1 were higher, and those of p62 were lower in the DM/G-CSF rats than in the DM/saline-treated rats. The mRNA expression of β-oxidation-related genes was higher in DM/G-CSF rats than in the DM/saline-treated rats. Quantification of lipid levels in HepG2 cells cultured with HG and G-CSF treatment revealed no significant differences.

CONCLUSIONS

Our data suggested that G-CSF potentially improves hepatic steatosis and autophagy in the liver of diabetic rats.

Influence of sociodemographic, lifestyle and genetic characteristics on maternal DHA and other polyunsaturated fatty acid status in pregnancy: A systematic review

INTRODUCTION

Omega-3 DHA is important for the prevention of preterm birth, however there is limited knowledge of the determinants of omega-3 status during pregnancy. The primary objective of this systematic review was to synthesise data from existing studies assessing relationships between sociodemographic, diet, lifestyle and genetic factors and maternal DHA status.

MATERIALS AND METHODS

The Medline, Embase, Amed, and CINAHL databases were searched for studies reporting measures of maternal omega-3 status and a sociodemographic/lifestyle/genetic characteristic.

RESULTS

Twenty-two studies were included in the final analyses. Higher dietary fish consumption/PUFA intake, higher education level and an older maternal age were associated with higher maternal omega-3 status. Higher alcohol intake, smoking and FADS genotype were each associated with lower maternal omega-3 status.

DISCUSSION

Differences in findings between studies make it difficult to draw clear conclusions about the relationship between these factors and maternal omega-3 DHA status, although socioeconomic status may play a role.

Fructo-oligosaccharides lower serum lipid levels and suppress high-fat/high-sugar diet-induced inflammation by elevating serum and gut levels of short-chain fatty acids

Objective

This study aimed to investigate the effects of fructo-oligosaccharides (FOS) on serum lipid levels and to determine the mechanisms underlying these effects and the potential role of inflammation.

Methods

Male C57BL/6 mice received a normal diet, a high-fat/high-sugar (HFS) diet, or an HFS diet supplemented with 10% FOS for 10 weeks. In vivo intestinal and serum short-chain fatty acid (SCFA) levels were measured by gas chromatography. In vivo serum levels of alanine transaminase (ALT), aspartate aminotransferase (AST), total cholesterol (TC), triglycerides (TG), high-density lipoprotein (HDL), low-density lipoprotein (LDL), interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), 8-hydroxy-2'-deoxyguanosine (8-OHdG), and malonaldehyde (MDA) were also measured. Lipid accumulation was visualized. Reactive oxygen species (ROS) generation was evaluated and apoptosis was quantified.

Results

FOS reversed in vivo HFS-induced lipid accumulation in the liver. An HFS diet increased ALT, AST, TC, TG, and LDL serum levels, decreased HDL serum levels, and increased IL-6, TNF-α, 8-OHdG, and MDA levels. These changes were reduced by FOS. FOS also increased intestinal and serum levels of short chain fatty acids (SCFAs). In vitro, SCFAs ameliorated palmitic acid-induced ROS production and apoptosis of HepG2 cells.

Conclusion

FOS supplementation lowers serum lipid levels and ameliorates HFS-induced inflammation by upregulating SCFAs.

Ultrasonic liver steatosis quantification by a learning-based acoustic model from a novel shear wave sequence

BACKGROUND

An efficient and accurate approach to quantify the steatosis extent of liver is important for clinical practice. For the purpose, we propose a specific designed ultrasound shear wave sequence to estimate ultrasonic and shear wave physical parameters. The utilization of the estimated quantitative parameters is then studied.

RESULTS

Shear wave attenuation, shear wave absorption, elasticity, dispersion slope and echo attenuation were simultaneously estimated and quantified from the proposed novel shear wave sequence. Then, a regression tree model was utilized to learn the connection between the space represented by all the physical parameters and the liver fat proportion. MR mDIXON quantification was used as the ground truth for liver fat quantification. Our study included a total of 60 patients. Correlation coefficient (CC) with the ground truth were applied to mainly evaluate different methods for which the corresponding values were - 0.25, - 0.26, 0.028, 0.045, 0.46 and 0.83 for shear wave attenuation, shear wave absorption, elasticity, dispersion slope, echo attenuation and the learning-based model, respectively. The original parameters were extremely outperformed by the learning-based model for which the root mean square error for liver steatosis quantification is only 4.5% that is also state-of-the-art for ultrasound application in the related field.

CONCLUSIONS

Although individual ultrasonic and shear wave parameters were not perfectly adequate for liver steatosis quantification, a promising result can be achieved by the proposed learning-based acoustic model based on them.

Effects of Eriobotrya japonica Water Extract on Alcoholic and Nonalcoholic Fatty Liver Impairment

The aim of this study was to investigate the potential protective effects of the hot water extract of Eriobotrya japonica (EJW) on EtOH- or free fatty acid (FFA)-induced fatty liver injury in vitro. HepG2/2E1 cells were exposed to EtOH and HepG2 cells were exposed to a mixture of FFAs (oleic acid:palmitic acid, 2:1) to stimulate oxidative stress and to induce lipid accumulation, respectively. Antioxidant activity was significantly increased and lipid accumulation was inhibited in cells pretreated with EJW compared to those in cells exposed to EtOH or FFA only. Also, 5'adenosine monophosphate (AMP)-activated protein kinase (AMPK) and acetyl-coenzyme A carboxylase (ACC) phosphorylations were considerably increased, indicating activation of AMPK. Furthermore, EJW reduced the messenger RNA (mRNA) expression of lipogenesis-associated factors such as ACC, sterol regulatory element binding protein-1c (SREBP-1c), and fatty acid synthase (FAS), and increased mRNA expression related to components of the fatty acid β-oxidation pathway, such as AMPK, carnitine palmitoyltransferase 1 (CPT-1), and peroxisome proliferator-activated receptor alpha (PPARα). These results suggest that EJW possessed potential preventive effects against both EtOH- and FFA-induced fatty liver disease by alleviation of oxidative stress and lipid accumulation in hepatocytes.

Macrophage Function in the Pathogenesis of Non-alcoholic Fatty Liver Disease: The Mac Attack

Obesity is a prevalent predisposing factor to non-alcoholic fatty liver disease (NAFLD), the most common chronic liver disease in the developed world. NAFLD spectrum of disease involves progression from steatosis (NAFL), to steatohepatitis (NASH), cirrhosis and hepatocellular carcinoma (HCC). Despite clinical and public health significance, current FDA approved therapies for NAFLD are lacking in part due to insufficient understanding of pathogenic mechanisms driving disease progression. The etiology of NAFLD is multifactorial. The induction of both systemic and tissue inflammation consequential of skewed immune cell metabolic state, polarization, tissue recruitment, and activation are central to NAFLD progression. Here, we review the current understanding of the above stated cellular and molecular processes that govern macrophage contribution to NAFLD pathogenesis and how adipose tissue and liver crosstalk modulates macrophage function. Notably, the manipulation of such events may lead to the development of new therapies for NAFLD.

Non-invasive assessment of hepatic lipid subspecies matched with non-alcoholic fatty liver disease phenotype

BACKGROUND AND AIMS

Nonalcoholic fatty liver disease (NAFLD) is characterized by excessive hepatic fat accumulation. Increased hepatic saturated fats and decreased hepatic polyunsaturated fats may be particularly lipotoxic, contributing to metabolic dysfunction. We compared hepatic lipid subspecies in adults with and without NAFLD, and examined links with hallmark metabolic and clinical characteristics of NAFLD.

METHODS AND RESULTS

Nineteen adults with NAFLD (total hepatic fat:18.8 ± 0.1%) were compared to sixteen adults without NAFLD (total hepatic fat: 2.1 ± 0.01%). ¹H-MRS was used to assess hepatic lipid subspecies. Methyl, allylic, methylene, and diallylic proton peaks were measured. Saturation, unsaturation, and polyunsaturation indices were calculated. Whole-body phenotyping in a subset of participants included insulin sensitivity (40 mU/m² hyperinsulinemic-euglycemic clamps), CT-measured abdominal adipose tissue depots, exercise capacity, and serum lipid profiles. Participants with NAFLD exhibited more saturated and less unsaturated hepatic fat, accompanied by increased insulin resistance, total and visceral adiposity, triglycerides, and reduced exercise capacity compared to controls (all P < 0.05). All proton lipid peaks were related to insulin resistance and hypertriglyceridemia (P < 0.05).

CONCLUSION

Participants with NAFLD preferentially stored excess hepatic lipids as saturated fat, at the expense of unsaturated fat, compared to controls. This hepatic lipid profile was accompanied by an unhealthy metabolic phenotype.

MicroRNA-29a Suppresses CD36 to Ameliorate High Fat Diet-Induced Steatohepatitis and Liver Fibrosis in Mice

MicroRNA-29 (miR-29) has been shown to play a critical role in reducing inflammation and fibrosis following liver injury. Non-alcoholic fatty liver disease (NAFLD) occurs when fat is deposited (steatosis) in the liver due to causes other than excessive alcohol use and is associated with liver fibrosis. In this study, we asked whether miR-29a could reduce experimental high fat diet (HFD)-induced obesity and liver fibrosis in mice. We performed systematical expression analyses of miR-29a transgenic mice (miR-29aTg mice) and wild-type littermates subjected to HFD-induced NAFLD. The results demonstrated that increased miR-29a not only alleviated HFD-induced body weight gain but also subcutaneous, visceral, and intestinal fat accumulation and hepatocellular steatosis in mice. Furthermore, hepatic tissue in the miR-29aTg mice displayed a weak fibrotic matrix concomitant with low fibrotic collagen1α1 expression within the affected tissues compared to the wild-type (WT) mice fed the HFD diet. Increased miR-29a signaling also resulted in the downregulation of expression of the epithelial mesenchymal transition-executing transcription factor snail, mesenchymal markers vimentin, and such pro-inflammation markers as il6 and mcp1 within the liver tissue. Meanwhile, miR-29aTg-HFD mice exhibited significantly lower levels of peroxisome proliferator-activated receptor γ (PPARγ), mitochondrial transcription factor A TFAM, and mitochondria DNA content in the liver than the WT-HFD mice. An in vitro luciferase reporter assay further confirmed that miR-29a mimic transfection reduced fatty acid translocase CD36 expression in HepG2 cells. Conclusion: Our data provide new insights that miR-29a can improve HDF-induced obesity, hepatocellular steatosis, and fibrosis, as well as highlight the role of miR-29a in regulation of NAFLD.

Chronic exposure to tetrabromodiphenyl ether (BDE-47) aggravates hepatic steatosis and liver fibrosis in diet-induced obese mice

Exposure to polybrominated diphenyl ethers (PBDEs), is closely associated with the occurrence of obesity and non-alcoholic fatty liver disease (NAFLD), yet their pathological effects and underlying mechanisms remain unclear. To examine the role of 2, 2', 4, 4'-tetrabromodiphenyl ether (BDE-47) in the progression of NAFLD under obese condition, male C57BL/6 J mice were fed with diet interaction for 15 weeks and subcutaneously injected with BDE-47 (7 mg/kg or 70 mg/kg) or the vehicle weekly. BDE-47 exposure (70 mg/kg) significantly elevated the body weight and worsened hepatic steatosis along with increased inflammation in high fat diet (HFD) fed mice. Furthermore, integration analysis of lipidomics and gene expression revealed that BDE-47 up-regulated triglyceride synthesis but suppressed lipid exportation and β oxidation, aggravating the accumulation of hepatic lipid in HFD fed mice. In addition, the increase of liver fibrosis, serum transaminase levels, as well as lipid peroxidation have been observed in mice co-treated with BDE-47 and HFD. Moreover, BDE-47-induced fibrogenic responses in hepatocytes were suppressed by antioxidants, which confirmed that BDE-47-induced liver fibrosis was tightly associated with oxidative stress. In conclusion, these results provided new and robust evidence for revealing the hepatoxicity of BDE-47 under obese condition and illustrated the underlying mechanism of BDE-47 induced liver fibrosis.

Fatty Liver Disease: A Practical Approach

CONTEXT.—

Fatty liver disease is now one of the most commonly encountered entities in the practice of liver pathology. Distinguishing simple steatosis from steatohepatitis is critical because the latter requires follow-up because of long-term risks that include cirrhosis and hepatocellular carcinoma. An organized approach for evaluating liver biopsies with steatosis is recommended to capture all of the relevant features: (1) degree of steatosis, (2) presence or absence of ballooning degeneration, (3) lobular inflammation, and (4) fibrosis. Herein, we provide a stepwise approach that readers can use to evaluate liver biopsies with steatosis, including examples, pitfalls, differential diagnostic considerations, and suggested diagnostic phrasing.

OBJECTIVE.—

To provide a stepwise approach for the evaluation of liver biopsies showing significant steatosis (involving ≥5% of liver parenchyma).

DATA SOURCES.—

Biopsies demonstrating fatty liver disease encountered in our daily practice were examined as well as recent literature.

CONCLUSIONS.—

Effective evaluation of liver biopsies with steatosis requires careful histologic examination and correlation with clinical history, particularly regarding medications, nutrition status, and alcohol use. Examples of uniform reporting, including appropriate use of the nonalcoholic steatohepatitis Clinical Research Network Activity Score, are provided.

An IKK/NF-κB Activation/p53 Deletion Sequence Drives Liver Carcinogenesis and Tumor Differentiation

Background: Most liver tumors arise on the basis of chronic liver diseases that trigger inflammatory responses. Besides inflammation, subsequent defects in the p53-signaling pathway frequently occurs in liver cancer. In this study, we analyzed the consequences of inflammation and p53 loss in liver carcinogenesis. Methods: We used inducible liver-specific transgenic mouse strains to analyze the consequences of NF-κB/p65 activation mimicking chronic inflammation and subsequent p53 loss. Results: Ikk2^ca driven NF-κB/p65 activation in mice results in liver fibrosis, the formation of ectopic lymphoid structures and carcinogenesis independent of p53 expression. Subsequent deletion of Trp53 led to an increased tumor formation, metastasis and a shift in tumor differentiation towards intrahepatic cholangiocarcinoma. In addition, loss of Trp53 in an inflammatory liver resulted in elevated chromosomal instability and indicated a distinct aberration pattern. Conclusions: In conclusion, activation of NF-κB/p65 mimicking chronic inflammation provokes the formation of liver carcinoma. Collateral disruption of Trp53 supports tumor progression and influences tumor differentiation and heterogeneity.

Hepatoprotective and Renoprotective Properties of Lovastatin-Loaded Ginger and Garlic Oil Nanoemulsomes: Insights into Serum Biological Parameters

Background and Objectives: Dyslipidemia is gaining much attention among healthcare professionals because of its high association with the malfunctioning of a number of normal physiological and metabolic processes in the body. Obesity is directly interconnected with dyslipidemia and is said to be a denouement of hyperlipidemia and, if left untreated, may lead to intense damage to organs that are directly involved in fat metabolism. The objective of this study was to investigate the synergistic antiobesity and anti-hyperlipidemic activities along with hepato- and renoprotective potential of nanoemulsomes (NES) of lovastatin (LTN)-loaded ginger (GR) and garlic (GL) oils. Materials and Methods: LTN nanoemulsomes co-encapsulated with GR oil and GL oil were prepared by a thin hydration technique. Eight-week-old male Wistar rats weighing 200-250 g were induced with hyperlipidemia via a high-fat diet (HFD) comprising 40% beef tallow. Body weight, serum biochemical lipid parameters, and those for liver and kidney functions, serum TC, LDL-C, vLDL-C, HDL-C, TG, atherogenic index (AI), ALT, AFT, ALP, γ-GT, total protein (TP), serum albumin and globulin ratio (A/G), serum creatinine, blood urea nitrogen (BUN) and blood urea, and histopathology of hematoxylin and eosin (H&E) stained liver and kidney sections of all aforementioned groups were examined in the treated animals. Results: Nanoemulsomes of LTN-loaded GR and GL oils provided synergistic effects with LTN, exerted better ameliorative actions in reducing serum TC, LDL-C, vLDL-C, triglycerides, and AI, and improved serum HDL-C levels. Serum ALT, AST, ALP, and γ-GT levels were in the normal range for nanoemulsome groups. H&E stained liver and kidney sections of these animals confirmed better hepatoprotective and renoprotective effects than LTN alone. Serum biochemical parameters for renal functions also claimed to be in the moderate range for nanoemulsome-treated groups. Conclusion: This study demonstrated that nanoemulsomes of LTN-loaded GR and GL oils synergistically provided better antihyperlipidemic, hepatoprotective, and renoprotective effects as compared to LTN alone.

Metabolomics in genetic testing

Metabolomics is an intriguing field of study providing a new readout of the biochemical activities taking place at the moment of sampling within a subject's biofluid or tissue. Metabolite concentrations are influenced by several factors including disease, environment, drugs, diet and, importantly, genetics. Metabolomics signatures, which describe a subject's phenotype, are useful for disease diagnosis and prognosis, as well as for predicting and monitoring the effectiveness of treatments. Metabolomics is conventionally divided into targeted (i.e., the quantitative analysis of a predetermined group of metabolites) and untargeted studies (i.e., analysis of the complete set of small-molecule metabolites contained in a biofluid without a pre-imposed metabolites-selection). Both approaches have demonstrated high value in the investigation and understanding of several monogenic and multigenic conditions. Due to low costs per sample and relatively short analysis times, metabolomics can be a useful and robust complement to genetic sequencing.

Dipeptidyl peptidase-4 inhibitors and aerobic exercise synergistically protect against liver injury in ovariectomized rats

Menopause increases the risk of non-alcoholic fatty liver disease (NAFLD). We investigated the effect of incretin and/ or exercise on the hepatic fat accumulation in ovariectomized rats. Rats were divided into five groups: Group 1: Control rats, Group 2: Ovariectomized rats, Group 3: Ovariectomized rats + Dipeptidyl peptidase-4 inhibitor (DPPi) (30 mg/kg/day, orally), Group 4: Ovariectomized rats + swimming, and Group 5: Ovariectomized rats + swimming + DPPi. After 6 weeks, Alanine aminotransferase (ALT), glucose, insulin, HOMA IR (Homeostatic Model Assessment for Insulin Resistance), FFA (free fatty acids), Tumor necrosis factor alpha (TNF α), IL6, IL1B levels were measured in blood. The livers were collected for Hematoxylin and eosin (H&E) examination and evaluation of hepatic gene expression of SREBP (sterol regulatory element-binding protein1c), PPAR α (peroxisome proliferator-activated receptor alpha), ACC 1 (acetyl-CoA carboxylase), LC3 (microtubule-associated protein 1 light chain 3), SIRT (sirtuin), hepatic triglycerides, IL6, IL10, caspase 3 and AMPK (adenosine monophosphate-activated protein kinase). A significant increase in ALT level and area of liver tissue defects with a significant increase in glucose HOMA IR, serum FFA, IL6, IL1B, TNF α, liver TGs (triglycerides), inflammation, apoptosis, SREBP1c, ACC1 were found in ovariectomized rats as compared to control group with a significant decrease in PPAR α, LC3, AMPK and SIRT1. DPPi treated rats with and without exercise showed a significant improvement in ALT and area of liver tissue defects, inflammation and apoptosis and serum IL6, IL1B, TNF α, FFA, liver LC3, SIRT1, AMPK, TGs, PPAR α, ACC1 and SREBP1c as compared to the ovariectomized group. Findings from the study confirm the derangement of fat metabolism in the ovariectomized rats and showed that incretin-based therapy and exercise synergistically improved liver fat metabolism, achieved significant beneficial metabolic effects and offer full protection against NAFLD.

Hepatic nitric oxide synthase 1 adaptor protein regulates glucose homeostasis and hepatic insulin sensitivity in obese mice depending on its PDZ binding domain

BACKGROUND

NOS1AP is an adaptor protein and its SNP rs12742393 was associated with type 2 diabetes (T2D). However, it remains uncertain whether NOS1AP plays a role in regulation of insulin sensitivity. Hepatic insulin resistance contributed to the development of T2D. Here, our investigation was focused on whether NOS1AP is involved in the regulation of hepatic insulin sensitivity and its underlying mechanisms.

METHODS

Liver specific NOS1AP condition knockout (CKO) and NOS1AP overexpression mice were generated and given a high fat diet. SNPs of NOS1AP gene were genotyped in 86 human subjects.

FINDINGS

NOS1AP protein is expressed in human and mouse liver. CKO mice exhibited impaired pyruvate, glucose and insulin tolerance, and increased lipid deposits in the liver. Conversely, NOS1AP overexpression in livers of obese mice improved pyruvate and/or glucose, and insulin tolerance, and attenuated liver lipid accumulation. Moreover, hepatocytes from CKO mice exhibited an elevated glucose production and mRNA expressions of Pc and Pck1. Overexpression of NOS1AP potentiated insulin-stimulated activation of IR/Akt in livers from obese mice. The insulin sensitizing effect of NOS1AP could be mimicked by overexpression of C-terminal domain of NOS1AP in ob/ob mice. Furthermore, NOS1AP overexpression in liver significantly inhibited p38 MAPK phosphorylation, and maintained ER homeostasis through p-eIF2a-ATF4-CHOP pathway. Subjects with rsl2742393 of NOS1AP have higher risk to develop hepatic steatosis.

INTERPRETATION

Our data demonstrate a novel role of NOS1AP in regulating hepatic insulin sensitivity and p38 MAPK inactivation in obese mice, which makes NOS1AP a potential therapeutic target for the prevention and treatment of T2D. FUND: This work was supported by the National Natural Science Foundation of China (81670707, 31340072) (to C. Wang), and National Basic Research Program of China (Nation 973 Program) (2011CB504001) (to W. Jia).

Hepatic SIRT3 Upregulation in Response to Chronic Alcohol Consumption Contributes to Alcoholic Liver Disease in Mice

Background

Alcoholic liver disease (ALD) is a type of chronic liver disease caused by chronic ethanol overconsumption. The pathogenesis of ALD is complex and there is no effective clinical treatment thus far. SIRT3 is an NAD⁺-dependent deacetylase primarily located inside mitochondria, and reports on the effect of chronic alcohol exposure on liver SIRT3 expression are scarce. This study aims to investigate the effect of chronic alcohol consumption on hepatic SIRT3 expression and its role in alcoholic-induced liver injury.

Methods

Using the Lieber-DeCarli mouse model of ALD, we analyzed the regulation of SIRT3 and the effect of liver-specific knocking-down of SIRT3 on alcohol-induced liver injury. HepG2 and AML12 hepatocytes were employed to detect the biological function of SIRT3 on alcohol-induced hepatic cytotoxicity and its potential mechanism.

Results

Chronic alcohol exposure led to hepatic SIRT3 upregulation and liver-specific SIRT3 knockdown alleviated alcoholic feeding-induced liver injury and lipid accumulation, which is associated with improved autophagy induction. In addition, autophagy induction contributed to the cytoprotective effect of SIRT3 knockdown on ethanol-induced hepatocyte cell death.

Conclusion

In summary, our data suggest that hepatic SIRT3 upregulation in response to chronic alcohol exposure and liver-specific SIRT3 knockdown, induced autophagy activation further alleviating alcoholic-induced liver injury, which represents a novel mechanism in this process.

Current Status in Testing for Nonalcoholic Fatty Liver Disease (NAFLD) and Nonalcoholic Steatohepatitis (NASH)

Nonalcoholic fatty liver disease (NAFLD) is the most common chronic liver disease in Western countries with almost 25% affected adults worldwide. The growing public health burden is getting evident when considering that NAFLD-related liver transplantations are predicted to almost double within the next 20 years. Typically, hepatic alterations start with simple steatosis, which easily progresses to more advanced stages such as nonalcoholic steatohepatitis (NASH), fibrosis and cirrhosis. This course of disease finally leads to end-stage liver disease such as hepatocellular carcinoma, which is associated with increased morbidity and mortality. Although clinical trials show promising results, there is actually no pharmacological agent approved to treat NASH. Another important problem associated with NASH is that presently the liver biopsy is still the gold standard in diagnosis and for disease staging and grading. Because of its invasiveness, this technique is not well accepted by patients and the method is prone to sampling error. Therefore, an urgent need exists to find reliable, accurate and noninvasive biomarkers discriminating between different disease stages or to develop innovative imaging techniques to quantify steatosis.

Effect of febuxostat on biochemical parameters of hyperlipidemia induced by a high-fat diet in rabbits

Febuxostat, a highly potent xanthine oxidase inhibitor with an antioxidant effect, inhibits elevated xanthine oxidase, leading to reduction of reactive oxygen species and oxidative stress, the main causes of vascular inflammation in hyperlipidemia. The aim of this study was to test the potential antioxidant and anti-inflammatory effects of febuxostat and (or) stopping a high-fat diet on the biochemical parameters in rabbits with hyperlipidemia induced by a high-fat diet. Male New Zealand rabbits were distributed into 3 groups: a normal control group fed standard chow for 12 weeks and 2 other groups fed a high-fat diet with 1% cholesterol for 8 weeks, and then shifted to standard chow for 4 weeks. During the last 4 weeks, one high-fat diet group received 0.5% carboxymethyl cellulose, whereas the other group was treated with febuxostat (2 mg/kg per day p.o.). Febuxostat significantly lowered low-density lipoprotein cholesterol (“bad” cholesterol) compared to the untreated group (high-fat diet group). Febuxostat also displayed a potent anti-inflammatory and antioxidant activity by decreasing serum levels of lipid peroxidation index, proinflammatory cytokines, and enhancing antioxidant enzyme activity. Stopping the hyperlipidemic diet in the high-fat diet group did not show improvement. These findings indicate the antioxidant and anti-inflammatory effects of febuxostat that may be common mechanisms of the anti-hyperlipidemic effect of this drug. Stopping a hyperlipidemic diet without treatment is not sufficient once injury has occurred.

Establishment of a human embryonic stem cell-based liver differentiation model for hepatotoxicity evaluations

The liver is one of the major targets of hormones, including thyroid hormones (THs), and many industrial chemicals, such as endocrine-disrupting chemicals. Those compounds may permeate the placenta barrier and pose a risk for embryonic development. Therefore, it is necessary to assess the toxic effects of those kind of industrial chemicals during liver development. In this study, to mimic liver specification in vitro, we differentiated human embryonic stem cells (ESCs) into functional hepatocyte-like cells. We performed this differentiation process in presence of two THs, triiodothyronine (T3) and thyroxine (T4), with the purpose of identifying biomarkers for toxicity screening. TH exposure (3, 30 and 300 nM) yielded to hepatocytes with impaired glycogen storage ability and abnormal lipid droplets' accumulation. Global gene expression analysis by RNA-seq identified a number of genes responsible for hepatic differentiation and function which were affected by 30 nM T3 and T4. Those differentially expressed genes were used to assess the potential developmental liver toxicity of two famous environmental pollutants, 2, 2, 4, 4-tetrabromodiphenyl ether (BDE-47) and decabromodiphenyl ether (BDE-209), at 10 nM to 1 μM treatments. Our findings demonstrate that BDE-47 and BDE-209, dysregulated pathways such as "chemical carcinogenesis", "steroid hormone biosynthesis" and "drug metabolism-cytochrome P450". Moreover, we were able to identify a set of 17 biomarkers, very useful to predict the potential developmental hepatotoxicity of industrial chemicals.

Diverse Consequences in Liver Injury in Mice with Different Autophagy Functional Status Treated with Alcohol

Alcoholic fatty liver disease is often complicated by other pathologic insults, such as viral infection or high-fat diet. Autophagy plays a homeostatic role in the liver but can be compromised by alcohol, high-fat diet, or viral infection, which in turn affects the disease process caused by these etiologies. To understand the full impact of autophagy modulation on alcohol-induced liver injury, several genetic models of autophagy deficiency, which have different levels of functional alterations, were examined after acute binge or chronic-plus-binge treatment. Mice given alcohol with either mode and induced with deficiency in liver-specific Atg7 shortly after the induction of Atg7 deletion had elevated liver injury, indicating the protective role of autophagy. Constitutive hepatic Atg7-deficient mice, in which Atg7 was deleted in embryos, were more susceptible with chronic-plus-binge but not with acute alcohol treatment. Constitutive hepatic Atg5-deficient mice, in which Atg5 was deleted in embryos, were more susceptible with acute alcohol treatment, but liver injury was unexpectedly improved with the chronic-plus-binge regimen. A prolonged autophagy deficiency may complicate the hepatic response to alcohol treatment, likely in part due to endogenous liver injury. The complexity of the relationship between autophagy deficiency and alcohol-induced liver injury can thus be affected by the timing of autophagy dysfunction, the exact autophagy gene being affected, and the alcohol treatment regimen.

Assessing the human health risks of perfluorooctane sulfonate by in vivo and in vitro studies

The wide use of perfluorooctane sulfonate (PFOS) has led to increasing concern about its human health risks over the past decade. In vivo and in vitro studies are important and effective means to ascertain the toxic effects of PFOS on humans and its toxic mechanisms. This article systematically reviews the human health risks of PFOS based on the currently known facts found by in vivo and in vitro studies from 2008 to 2018. Exposure to PFOS has caused hepatotoxicity, neurotoxicity, reproductive toxicity, immunotoxicity, thyroid disruption, cardiovascular toxicity, pulmonary toxicity, and renal toxicity in laboratory animals and many in vitro human systems. These results and related epidemiological studies confirmed the human health risks of PFOS, especially for exposure via food and drinking water. Oxidative stress and physiological process disruption based on fatty acid similarity were widely studied mechanisms of PFOS toxicity. Future research for assessing the human health risks of PFOS is recommended in the chronic toxicity and molecular mechanisms, the application of various omics, and the integration of toxicological and epidemiological data.

A Novel Dietary Source of EPA and DHA: Metabolic Engineering of an Important Freshwater Species-Common Carp by fat1-Transgenesis

Omega-3 polyunsaturated fatty acids (n-3 PUFAs), such as eicosapentaenoic acid (20:5n-3, EPA) and docosahexaenoic acid (22:6n-3, DHA), are essential for neural development and human health. The n-3 PUFAs are mainly obtained from marine fish by dietary intake. Freshwater fish species usually contain low level of n-3 PUFAs due to the lack of n-3 PUFAs in their food chain. In this study, we report on the substantial production of EPA and DHA in a globally important freshwater fish species, common carp (Cyprinus carpio). This was achieved by introducing an "all-fish" transgene CA:fat1 containing the fish codon-optimized omega-3 desaturase gene (fat1) driven by the common carp β-actin promoter (CA). Through a sperm sample screening method, we successfully generated fat1-positive F1 transgenic population with high efficiency. In F1 population, the muscle contents of ALA (18:3n-3), EPA and DHA were significantly increased when compared with non-transgenic siblings. Thereafter, four independent F2 heterozygous lines were obtained from 4 F1 transgenic males and a detailed comparison of fatty acids profile and growth performance was carried out for these 4 lines. All fat1-transgenic common carps from 4 lines showed an evident decrease in n-6 PUFA contents and a substantial increase in n-3 PUFA contents, among which line 4 stands out, showing a statistically significant increase in all 4 types of n-3 PUFAs including ALA (4.4-fold increase, p < 0.001), EPA (4.8-fold increase, p < 0.01), C22:5n-3 (DPA, 2.4-fold increase, p < 0.05), and DHA (1.9-fold increase, p < 0.05). Therefore, the line 4 was selected as the optimized breeding stock for further study, and the proximate nutrition composition and PUFA synthesis pathway were analyzed. Our study demonstrates that in the transgenic group, the muscular lipid content did not change, while fat accumulations in the internal organs and especially in the liver were significantly decreased as a result of hyperactivation of fatty acid oxidation process. Finally, we conclude that the "all-fish" CA:fat1-transgenic freshwater fish-common carp-can serve as a novel healthy dietary source of n3-PUFAs, especially EPA and DHA.

Inhibition of soluble epoxide hydrolase ameliorates hyperhomocysteinemia-induced hepatic steatosis by enhancing β-oxidation of fatty acid in mice

Hepatic steatosis is the beginning phase of nonalcoholic fatty liver disease, and hyperhomocysteinemia (HHcy) is a significant risk factor. Soluble epoxide hydrolase (sEH) hydrolyzes epoxyeicosatrienoic acids (EETs) and other epoxy fatty acids, attenuating their cardiovascular protective effects. However, the involvement of sEH in HHcy-induced hepatic steatosis is unknown. The current study aimed to explore the role of sEH in HHcy-induced lipid disorder. We fed 6-wk-old male mice a chow diet or 2% (wt/wt) high-metnionine diet for 8 wk to establish the HHcy model. A high level of homocysteine induced lipid accumulation in vivo and in vitro, which was concomitant with the increased activity and expression of sEH. Treatment with a highly selective specific sEH inhibitor (0.8 mg·kg^-1·day^-1 for the animal model and 1 μM for cells) prevented HHcy-induced lipid accumulation in vivo and in vitro. Inhibition of sEH activated the peroxisome proliferator-activated receptor-α (PPAR-α), as evidenced by elevated β-oxidation of fatty acids and the expression of PPAR-α target genes in HHcy-induced hepatic steatosis. In primary cultured hepatocytes, the effect of sEH inhibition on PPAR-α activation was further confirmed by a marked increase in PPAR-response element luciferase activity, which was reversed by knock down of PPAR-α. Of note, 11,12-EET ligand dependently activated PPAR-α. Thus increased sEH activity is a key determinant in the pathogenesis of HHcy-induced hepatic steatosis, and sEH inhibition could be an effective treatment for HHcy-induced hepatic steatosis. NEW & NOTEWORTHY In the current study, we demonstrated that upregulation of soluble epoxide hydrolase (sEH) is involved in the hyperhomocysteinemia (HHcy)-caused hepatic steatosis in an HHcy mouse model and in murine primary hepatocytes. Improving hepatic steatosis in HHcy mice by pharmacological inhibition of sEH to activate peroxisome proliferator-activated receptor-α was ligand dependent, and sEH could be a potential therapeutic target for the treatment of nonalcoholic fatty liver disease.

Near-Infrared Irradiation Affects Lipid Metabolism in Neuronal Cells, Inducing Lipid Droplets Formation

It is known that lipids play an outstanding role in cellular regulation, and their dysfunction has been linked to many diseases. Thus, modulation of lipid metabolism may provide new pathways for disease treatment or prevention. In this work, near-infrared (NIR) light was applied to modulate lipid metabolism and increase intracellular lipid content in rat cortical neurons (RCN). Using label-free CARS microscopy, we have monitored the intracellular lipid content in RCN at a single-cell level. A major increase in average level of lipid per cell after treatment with laser diode at 808 nm was found, nonlinearly dependent on the irradiation dose. Moreover, a striking formation of lipid droplets (LDs) in the irradiated RCN was discovered. Further experiments and analysis reveal a strong correlation between NIR light induced generation of reactive oxygen species (ROS), lipids level, and LDs formation in RCN. Our findings can contribute to a development of therapeutic approaches for neurological disorders via NIR light control of lipid metabolism in neuronal cells.

Ghrelin acylation by ghrelin- O-acyltransferase can occur in healthy part of oncological liver in humans

Activation of ghrelin is controlled by the enzyme ghrelin- O-acyl transferase (GOAT). In humans, localization of this acylation is poorly understood. The aim of this study is to explore GOAT localization and activation in the human liver by evaluating both bioactive and non-bioactive ghrelin in the bloodstream entering and leaving the liver and to simultaneously evaluate GOAT mRNA expression in the liver. A healthy part of oncologic hepatic tissue collected from nine patients undergoing hepatectomy was used to evaluate GOAT mRNA expression by quantitative real-time polymerase chain reaction (RT-qPCR). Simultaneously, blood from the portal vein, the suprahepatic vein, the subclavicular vein, and the radial artery was also sampled to assay total and acylated ghrelin. Acylated ghrelin level was significantly increased in the suprahepatic vein compared with the portal vein level (385 ± 42 ng/ml vs. 268 ± 24 ng/ml, P = 0.04). Suprahepatic-to-portal vein ratio for acylated ghrelin (acylation ratio) is 1.4 ± 0.1. Mean expression of GOAT mRNA in the liver, expressed as 2^-∆Ct·µg total RNA^-1·1 µl of liver tissue^-1 was at 0.042 ± 0.021 arbitrary units. GOAT mRNA expression in the liver was correlated with acylated-to-total ghrelin ratio in the suprahepatic vein ( P = 0.016, R = 0.75) and with the acylation liver ratio ( P = 0.05, R = 0.61). Blood concentration of acylated ghrelin was found significantly increased after its passage through the liver, suggesting that acylation can occur in the liver. RT-qPCR data confirmed the presence of GOAT in the liver, with a positive correlation between GOAT expression and acylated ghrelin liver ratio. This study strongly suggests that the liver is a site of ghrelin acylation in humans. NEW & NOTEWORTHY Although the activation of ghrelin by the enzyme ghrelin- O-acyl transferase (GOAT) is yet well demonstrated, its localization, especially in humans, remains poorly understood. We explored GOAT localization and activation in the human liver by simultaneously evaluating both bioactive and non-bioactive ghrelin in the bloodstream entering and leaving the liver and also GOAT mRNA expression in the liver. We therefore showed for the first time, to our knowledge, that GOAT localized in the liver is active and takes part in ghrelin activation.

Lycopus lucidus Turcz. ex Benth. Attenuates free fatty acid-induced steatosis in HepG2 cells and non-alcoholic fatty liver disease in high-fat diet-induced obese mice

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) is closely related to metabolic diseases such as obesity and insulin resistance.

PURPOSE

We studied whether an ethanol extract of Lycopus lucidus Turcz. ex Benth (LLE) exhibited effects on lipid metabolism in NAFLD.

STUDY DESIGN

An in vitro modelwas established by treatment of HepG2 cells with a 1 mM free fatty acid (FFA) mixture (oleic acid/palmitic acid, 2:1). C57BL/6 mice were fed a high-fat diet (HFD; 60 kcal% fat) for 14 weeks to induce obesity and were treated with or without LLE (100 or 200  mg/kg daily by oral gavage).

METHODS

HepG2 cells were exposed to 1 mM FFA, with or without LLE (250 - 1000  mg/ml). Intracellular lipid contents were measured by Oil Red O staining and a Nile Red assay. The body weight, relative liver weight, hepatic lipids, triglycerides (TGs), and total cholesterol (TC) were measured in the mice. Serum alanine aminotransferase (ALT), TG, TC, glucose, insulin, leptin, and tumor necrosis factor-alpha (TNF-α) levels were determined by biochemical or enzyme-linked immunosorbent assays. Histologic analysis was performed in the liver. Western blotting and quantitative real-time polymerase chain reaction were used to analyze the expression of key enzymes of hepatic lipid metabolism.

RESULTS

LLE significantly decreased the intracellular lipid accumulation in FFA-treated HepG2 cells. LLE not only remarkably decreased the expression of lipogenesis genes but also increased β-oxidation in FFA-induced HepG2 cells. In the in vivo study, LLE treatment significantly decreased the body weight, relative liver weight, serum ALT, TC, and low-density lipoprotein cholesterol, as well as the serum glucose, insulin, leptin, and TNF-α levels in HFD-fed mice. The hepatic TG and TC contents were significantly reduced in the LLE-treated groups. Western blot analysis showed that the expression of sterol-regulatory element-binding protein 1 decreased, while that of phosphorylated AMP-activated protein kinase and peroxisome proliferator-activated receptor α increased in the LLE-treated mice.

CONCLUSION

These results suggest that LLE may exert protective effects against NAFLD-related obesity and metabolic disease.

The Hepatic Lipidome: A Gateway to Understanding the Pathogenes is of Alcohol-Induced Fatty Liver

Chronic alcohol consumption can lead to the development of alcoholic fatty liver disease. The underlying pathogenic mechanisms however, have not been fully elucidated. Here, we review the current state of the art regarding the application of lipidomics to study alcohol's effect on hepatic lipids. It is clear that alcohol has a profound effect on the hepatic lipidome, with documented changes in the major lipid categories (i.e. fatty acyls, glycerolipids, glycerophospholipids, sphingolipids, sterol lipids and prenol lipids). Alcohol's most striking effect is the marked change in the hepatic fatty acyl pool. This effect includes increased levels of 18-carbon fatty acyl chains incorporated into multiple lipid species, as well as a general shift toward increased unsaturation of fatty acyl moieties. In addition to our literature review, we also make several recommendations to consider when designing lipidomic studies into alcohol's effects. These recommendations include integration of lipidomic data with other measures of lipid metabolism, inclusion of multiple experimental time points, and presentation of quantitative data. We believe rigorous analysis of the hepatic lipidome can yield new insight into the pathogenesis of alcohol-induced fatty liver. While the existing literature has been largely descriptive, the field is poised to apply lipidomics to yield a new level of understanding on alcohol's effects on hepatic lipid metabolism.

Mapping tissue water T1 in the liver using the MOLLI T1 method in the presence of fat, iron and B0 inhomogeneity

Modified Look-Locker inversion recovery (MOLLI) T1 mapping sequences can be useful in cardiac and liver tissue characterization, but determining underlying water T1 is confounded by iron, fat and frequency offsets. This article proposes an algorithm that provides an independent water MOLLI T1 (referred to as on-resonance water T1 ) that would have been measured if a subject had no fat and normal iron, and imaging had been done on resonance. Fifteen NiCl2 -doped agar phantoms with different peanut oil concentrations and 30 adults with various liver diseases, nineteen (63.3%) with liver steatosis, were scanned at 3 T using the shortened MOLLI (shMOLLI) T1 mapping, multiple-echo spoiled gradient-recalled echo and 1 H MR spectroscopy sequences. An algorithm based on Bloch equations was built in MATLAB, and water shMOLLI T1 values of both phantoms and human participants were determined. The quality of the algorithm's result was assessed by Pearson's correlation coefficient between shMOLLI T1 values and spectroscopically determined T1 values of the water, and by linear regression analysis. Correlation between shMOLLI and spectroscopy-based T1 values increased, from r = 0.910 (P < 0.001) to r = 0.998 (P < 0.001) in phantoms and from r = 0.493 (for iron-only correction; P = 0.005) to r = 0.771 (for iron, fat and off-resonance correction; P < 0.001) in patients. Linear regression analysis revealed that the determined water shMOLLI T1 values in patients were independent of fat and iron. It can be concluded that determination of on-resonance water (sh)MOLLI T1 independent of fat, iron and macroscopic field inhomogeneities was possible in phantoms and human subjects.

Homeostasis of Glucose and Lipid in Non-Alcoholic Fatty Liver Disease

Industrialized society-caused dysregular human behaviors and activities such as overworking, excessive dietary intake, and sleep deprivation lead to perturbations in the metabolism and the development of metabolic syndrome. Non-alcoholic fatty liver disease (NAFLD), the most common chronic liver disease worldwide, affects around 30% and 25% of people in Western and Asian countries, respectively, which leads to numerous medical costs annually. Insulin resistance is the major hallmark of NAFLD and is crucial in the pathogenesis and for the progression from NAFLD to non-alcoholic steatohepatitis (NASH). Excessive dietary intake of saturated fats and carbohydrate-enriched foods contributes to both insulin resistance and NAFLD. Once NAFLD is established, insulin resistance can promote the progression to the more severe state of liver endangerment like NASH. Here, we review current and potential studies for understanding the complexity between insulin-regulated glycolytic and lipogenic homeostasis and the underlying causes of NAFLD. We discuss how disruption of the insulin signal is associated with various metabolic disorders of glucoses and lipids that constitute both the metabolic syndrome and NAFLD.

Symposium review: Milk fat globule size: Practical implications and metabolic regulation

Milk fat globule (MFG) size ranges over 3 orders of magnitude, from less than 200 nm to over 15 µm. The significance of MFG size derives from its tight association with its lipidome and proteome. More specifically, small MFG have relatively higher content of membrane compared with large globules, and this membrane exerts diverse positive health effects, as reported in human and animal studies. In addition, MFG size has industrial significance, as it affects the physicochemical and sensory characteristics of dairy products. Studies on the size regulation of MFG are scarce, mainly because various confounders indirectly affect MFG size. Because MFG size is determined before and during its secretion from mammary epithelial cells, studies on the size regulation of its precursors, the intracellular lipid droplets (LD), have been used as a proxy for understanding the mechanisms controlling MFG size. In this review, we provide evidence for 2 distinct mechanisms regulating LD size in mammary epithelial cells: co-regulation of fat content and triglyceride-synthesis capacity of the cells, and fusion between LD. The latter is controlled by the membrane's polar lipid composition and involves mitochondrial enzymes. Accordingly, this review also discusses MFG size regulation in the in vivo metabolic context, as MFG morphometric features are often modulated under conditions that involve animals' altered energy status.

HNF1α Controls Liver Lipid Metabolism and Insulin Resistance via Negatively Regulating the SOCS-3-STAT3 Signaling Pathway

This study is aimed at evaluating the effects, functions, and mechanism of HNF1α on hepatic glycolipid metabolism. In this study, free fatty acid- (FFA-) induced steatosis of hepatocyte liver cell LO2 was used as an in vitro model. The methods of Oil Red O staining, RT-qPCR, western blot, and immunofluorescence staining were used to detect LO2-regulated HNF1α expression and its effects on FFA-induced LO2 cell steatosis, the insulin signaling and SOCS-3-STAT3 signaling pathways, the expression of lipid metabolism-related regulators, and phosphorylation. With increased FFA induction time, the expression of HNF1α in the LO2 fatty degeneration hepatic cells gradually decreased. Downregulation of HNF1α expression aggravated FFA-induced steatosis of LO2 hepatocytes. HNF1α promotes activation of the insulin pathway and oxidative breakdown of fat and inhibits lipid anabolism. Inhibitors of STAT3 can reverse the regulation of decreased HNF1α expression on the insulin signaling pathway and fat metabolism. We also confirmed this pathway using HNF1α-/- mice combining treatment with STAT3 inhibitor NSC 74859 in vivo. HNF1α regulates hepatic lipid metabolism by promoting the expression of SOCS-3 and negatively regulating the STAT3 signaling pathway.

Characterization of Growth, Fat Deposition, and Lipid Metabolism-Related Gene Expression in Lean and Obese Meat-Type Chickens

Excessive fat deposition adversely affects poultry production. In this study, we investigated growth, fat deposition, and hepatic mRNA expression of 13 lipid metabolism-related genes in three unique breeds of meat-type chickens with distinct breed origins and genetic relationships. One was Nagoya (NAG), a native Japanese breed, whereas the others were White Plymouth Rock (WPR) and White Cornish (WC), which have been used worldwide as the parental breeds of common broiler chickens. NAG chickens were phenotypically characterized by slow growth, lean body fat, and high gizzard and liver weights. In contrast, both WC and WPR chickens were characterized by rapid growth but high percentage of subcutaneous fat and abdominal fat weight, resulting from high feed intake. Among the three breeds, WC had the highest percentage of pectoral muscle weight, whereas WPR was the most obese. Among lipid metabolism-related genes, the expression of PPARA, PPARG, and CD36 was mostly associated with obesity. These results provide basic information for quantitative trait locus (QTL) analysis related to growth and fat traits in an F₂ population of the lean NAG breed and the obese WPR breed of meat-type chickens in future.

Association of thirty-year alcohol consumption typologies and fatty liver: Findings from a large population cohort study

OBJECTIVE

To evaluate the longitudinal relationship between repeated measures of alcohol consumption and risk of developing fatty liver.

PATIENTS AND METHODS

This study includes 5407 men and women from a British population-based cohort, the Whitehall II study of civil servants, who self-reported alcohol consumption by questionnaire over approximately 30 years (1985-1989 through to 2012-2013). Drinking typologies during midlife were linked to measures of fatty liver (the fatty liver index, FLI) when participants were in older age (age range 60-84 years) and adjusted for age, socio-economic position, ethnicity, and smoking.

RESULTS

Those who consistently drank heavily had two-fold higher odds of increased FLI compared to stable low-risk moderate drinkers after adjustment for covariates (men: OR = 2.04, 95%CI = 1.53-2.74; women: OR = 2.24, 95%CI = 1.08-4.55). Former drinkers also had an increased FLI compared to low-risk drinkers (men: OR = 2.09, 95%CI = 1.55-2.85; women: OR = 1.68, 95%CI = 1.08-2.67). There were non-significant differences in FLI between non-drinkers and stable low-risk drinkers. Among women, there was no increased risk for current heavy drinkers in cross sectional analyses.

CONCLUSION

Drinking habits among adults during midlife affect the development of fatty liver, and sustained heavy drinking is associated with an increased FLI compared to stable low-risk drinkers. After the exclusion of former drinkers, there was no difference between non-drinkers and low-risk drinkers, which does not support a protective effect on fatty liver from low-risk drinking. Cross-sectional analyses among women did not find an increased risk of heavy drinking compared to low-risk drinkers, thus highlighting the need to take a longitudinal approach.

Diabetes Mellitus, Nonalcoholic Fatty Liver Disease, and Conjugated Linoleic Acid (Omega 6): What Is the Link?

BACKGROUND AND OBJECTIVE

Type 2 DM and obesity are the coming epidemics and their association with NAFLD is well established; essential fatty acids are vital for body health yet the body cannot make them; 2 essential fatty acids are especially important: linoleic (omega-6) and alpha-linoleic (omega-3) acids; they can be considered as "bioactive lipids" and serve as functional foods.

METHODS

50 type 2 Egyptian diabetic patients controlled on oral hypoglycemic drugs together with 20 age- and sex-matched healthy participants were enrolled in the study; all were subjected to complete history taking, BMI, fasting plasma glucose, HOMA-IR, ALT, AST, GGT, urea and creatinine, total lipid profile, hepatitis markers including hepatitis B surface antigen and hepatitis C virus antibodies, conjugated linoleic fatty acid "CLA," and abdominal ultrasound for grading of NAFLD.

RESULTS

Our study in Egyptian diabetics with NAFLD revealed a low level of serum CLA compared to healthy control; such deficiency was more marked with advanced grades of NAFLD; lowest levels were observed in those with severe steatosis (NASH) with definite association between CLA and obesity.

CONCLUSION

Insulin resistance is the main link between NAFLD, diabetes, and obesity. Conjugated linoleic acid (CLA) has a role in fat deposition in the liver and in development and improvement of insulin resistance. Fatty food had a documented role in the pathogenesis of obesity and diabetes but it can also be the cure.

Flavone glycosides from Sicyos angulatus and their inhibitory effects on hepatic lipid accumulation

A library of extracted natural materials (Korea Bioactive Natural Material Bank) have been screened to discover candidates for the treatment of non-alcoholic liver disease (NAFLD), and the 70% ethanol extract of Sicyos angulatus was found to inhibit hepatic lipid accumulation. Bioassay-guided fractionation of this bioactive extract yielded five previously undescribed flavonoid glycosides and one previously undescribed flavonolignan glycoside along with seven known flavonoid glycosides. The chemical structures of these compounds were elucidated by a combination of extensive spectroscopic analysis, including MS, NMR and UV techniques. Eight compounds of all isolated compounds showed inhibitory effects on the lipid accumulation induced by high concentrations of palmitic acid and glucose in HepG2 cells. Four selected compounds were tested for lipid content in a dose-dependent manner (10, 20 and 40 μM), and among those compounds, kaempferol 3-O-β-d-glucopyranosyl-7-O-α-l-rhamnopyranoside showed the strongest inhibition of hepatic lipid production in HepG2 cells. In an oil-red O staining assay, five compounds were shown to reduce hepatic lipid accumulation better than what was observed in the vehicle control group. The present study suggests a new class of chemical entities for developing bioactive agents for the treatment of diseases caused by fat accumulation in the liver.

Trivalent Chromium Supplementation Ameliorates Oleic Acid-Induced Hepatic Steatosis in Mice

Trivalent chromium [Cr(III)] is recognized as an essential trace element for human health, whereas its effect on hepatic lipid metabolism has not yet been fully understood. This study aimed to investigate the beneficial effects and potential mechanisms of Cr(III) on hepatic steatosis in an oleic acid (OA) induced mice model. Mice were fed with high OA for 12 weeks to induce lipid accumulation, and co-administrated with Cr(III) supplementation. Indexes of liver lipid accumulation, associated lipid genes expression, fatty acids (FAs) profile and inflammatory cytokines were analyzed. The data showed that Cr(III) supplementation could attenuate disease progress of hepatic steatosis and protect liver from high OA. After Cr(III) supplementation, elevated body weight and liver injury in steatosis mice were reversed, excessive lipid accumulation and FAs were also reduced. The up-regulation of cluster of differentiation 36 (CD36) and diacylglycerol acyltransferase 2 (DGAT2) following steatosis induction were inhibited by Cr(III). Cr(III) reduced the content of pro-inflammatory cytokines (IL-1β and TNF-α, IL-12) and restored the level of anti-inflammatory cytokine (IL-10) to the control values. Our results suggest that Cr(III) supplementation is a novel strategy for alleviating OA-induced hepatic steatosis.

Maternal perinatal calorie restriction temporally regulates the hepatic autophagy and redox status in male rat

Intrauterine growth restriction (IUGR) leads to adult obesity, cardiovascular disease, and non-alcoholic fatty liver disease/steatohepatitis. Animal models have shown that combined intrauterine and early postnatal calorie restriction (IPCR) ameliorates these sequelae in adult life. The mechanism by which IPCR protects against adult onset disease is not understood. Autophagy, a lysosomal degradative process, recycles cellular constituents and eliminates damaged organelles, proteins, and oxidants. In this study, we hypothesized that IPCR could regulate autophagy in the liver of male rat offspring. At birth (d1) of male IUGR rat offspring and on day 21 (p21) of life, IPCR male rat offspring had a profound decrease in hepatic autophagy in all three stages of development: initiation, elongation, and maturation. However, upon receiving a normal diet ad-lib throughout adulthood, aged IPCR rats (day 450 of life (p450)), had increased hepatic autophagy, in direct contrast to what was seen in early life. The decreased autophagy at d21 led to the accumulation of ubiquitinated proteins and lipid oxidative products, whereas the increased autophagy in late life had the opposite effect. Oxidized lipids were unchanged at d1 by IUGR treatment indicating that decreased autophagy precedes oxidative stress in early life. When cellular signaling pathways regulating autophagy were examined, the 5' adenosine monophosphate-activated protein kinase pathway (AMPK), and not endoplasmic stress pathways, was found to be altered, suggesting that autophagy is regulated through AMPK signaling pathway in IPCR rats. Taken together, this study reveals that the perinatal nutritional status establishes a nutritionally sensitive memory that enhances hepatic autophagy in late life, a process that perhaps acts as a protective mechanism to limited nutrition.

The impact of cell fixation on coherent anti-stokes Raman scattering signal intensity in neuronal and glial cell lines

A number of studies require sample fixation, aimed to preserve cells in a physiological state with minimal changes of morphology and intracellular molecular content. Sample fixation may significantly distort experimental data, which makes the data interpretation process more challenging. It is particularly important for study of lipid-related diseases, where the biochemical and morphological characteristics of the cells need to be well preserved for an accurate data analysis. This study investigates the effects of formaldehyde and ethanol (EtOH) fixatives on coherent anti-stokes Raman scattering (CARS) signal of proteins and lipids in major cellular compartments of neuronal and glial cells. We found that both fixatives induce alteration of proteins and lipids signal in studied cell lines. Furthermore, the impact of sample preservation methods on CARS signal varies between cell lines. For instance, our data reveals that EtOH fixation induces ~45% increase of CARS signal of proteins in the nucleolus of neuronal cells and ~35% decrease of CARS signal in glial cells. The results indicate that aldehyde fixation is a preferable method for preservation of neuronal and glial cells prior to CARS imaging, as it less affects both CARS signal and intracellular distribution of proteins and lipids.

Non-HDL-cholesterol to HDL-cholesterol ratio is an independent risk factor for liver function tests abnormalities in geriatric population

Background

Excessive lipid depositing in liver cells could induce pathophysiological development of liver. Our study aimed to assess whether non-HDL cholesterol to HDL-cholesterol ratio (NonHDLc/HDLc) is an independent risk factor for liver function tests (LFTs) abnormalities in geriatric population.

Methods

We enrolled 1745 eligible subjects (714 males, 1031 females) with normal liver function tests at baseline who participated in annual health checkup for liver disease in 2015. Logistic regression models were used to examine the independent relationship between NonHDLc/HDLc ratio and LFTs abnormalities.

Results

After one year follow-up, there were 6.1% (n = 107) participants developed new-onset LFTs abnormalities in 2016. Equally dividing participants into tertiles according to their baseline NonHDLc/HDLc ratio levels, we found compared with tertile 1, the multivariable-adjusted ORs (95% CIs) for new-onset LFTs abnormalities of tertile 3 were 2.85 (1.18–6.93), P = 0.021. In stratified analysis, compared with controls, the correlation between NonHDLc/HDLc ratio and incidence of LFTs abnormalities was more remarkable in female individuals, BMI > 24 individuals and free of diabetes individuals.

Conclusion

Our study suggests that NonHDLc/HDLc ratio is an independent risk factor for LFTs abnormalities in geriatric population, and assessment of NonHDLc/HDLc ratio may help early identify high risk people of liver diseases.

Trial registration

Trial registration in the Ethics Committee of Tongji Medical College, Huazhong University of Science and Technology (IORG No: IORG0003571). Registered 3 March 2015.

Electronic supplementary material

The online version of this article (10.1186/s12944-018-0940-0) contains supplementary material, which is available to authorized users.

Regulatory Efficacy of Spirulina platensis Protease Hydrolyzate on Lipid Metabolism and Gut Microbiota in High-Fat Diet-Fed Rats

Lipid metabolism disorder (LMD) is a public health issue. Spirulina platensis is a widely used natural weight-reducing agent and Spirulina platensis is a kind of protein source. In the present study, we aimed to evaluate the effect of Spirulina platensis protease hydrolyzate (SPPH) on the lipid metabolism and gut microbiota in high-fat diet (HFD)-fed rats. Our study showed that SPPH decreased the levels of triglyceride (TG), total cholesterol (TC), low-density-lipoprotein cholesterol (LDL-c), alanine transaminase (ALT), and aspartate transaminase (AST), but increased the level of high-density-lipoprotein cholesterol (HDL-c) in serum and liver. Moreover, SPPH had a hypolipidemic effect as indicated by the down-regulation of sterol regulatory element-binding transcription factor-1c (SREBP-1c), acetyl CoA carboxylase (ACC), SREBP-1c, and peroxisome proliferator-activated receptor-γ (PPARγ) and the up-regulation of adenosine 5'-monophosphate (AMP)-activated protein kinase (AMPK) and peroxisome proliferator-activated receptorα (PPARα) at the mRNA level in liver. SPPH treatment enriched the abundance of beneficial bacteria. In conclusion, our study showed that SPPH might be produce glucose metabolic benefits in rats with diet-induced LMD. The mechanisms underlying the beneficial effects of SPPH on the metabolism remain to be further investigated. Collectively, the above-mentioned findings illustrate that Spirulina platensis peptides have the potential to ameliorate lipid metabolic disorders, and our data provides evidence that SPPH might be used as an adjuvant therapy and functional food in obese and diabetic individuals.

Mild Methylenetetrahydrofolate Reductase Deficiency Alters Inflammatory and Lipid Pathways in Liver

SCOPE

Dietary and genetic folate disturbances can lead to nonalcoholic fatty liver disease (NAFLD). A common variant in methylenetetrahydrofolate reductase (MTHFR 677C→T) causes mild MTHFR deficiency with lower 5-methyltetrahydrofolate for methylation reactions. The goal is to determine whether mild murine MTHFR deficiency contributes to NAFLD-related effects.

METHODS AND RESULTS

Wild-type and Mthfr^+/- mice, a model for the human variant, are fed control (CD) or high-fat (HFAT) diets for 8 weeks. On both diets, MTHFR deficiency results in decreased S-adenosylmethionine, increased S-adenosylhomocysteine, and decreased betaine with reduced methylation capacity, and changes in expression of several inflammatory or anti-inflammatory mediators (Saa1, Apoa1, and Pon1). On CD, MTHFR deficiency leads to microvesicular steatosis with expression changes in lipid regulators Xbp1s and Cyp7a1. The combination of MTHFR deficiency and HFAT exacerbates changes in inflammatory mediators and introduces additional effects on inflammation (Saa2) and lipid metabolism (Nr1h4, Srebf1c, Ppara, and Crot). These effects are consistent with increased expression of pro-inflammatory HDL precursors and greater lipid accumulation. MTHFR deficiency may enhance liver injury through alterations in methylation capacity, inflammatory response, and lipid metabolism.

CONCLUSION

Individuals with the MTHFR variant may be at increased risk for liver disease and related complications, particularly when consuming high-fat diets.

The polyherbal drug GGEx18 from Laminaria japonica, Rheum palmatum, and Ephedra sinica inhibits hepatic steatosis and fibroinflammtion in high-fat diet-induced obese mice

ETHNOPHARMACOLOGICAL RELEVANCE

The herbal composition Gyeongshingangjeehwan 18 (GGEx18), composed of Rheum palmatum L. (Polygonaceae), Laminaria japonica Aresch (Laminariaceae), and Ephedra sinica Stapf (Ephedraceae), is used as an antiobesity drug in Korean clinics. The constituents of GGEx18 have traditionally been reported to inhibit obesity and related metabolic diseases such as insulin resistance and dyslipidemia.

OBJECTIVE

This study investigated the effects of GGEx18 on nonalcoholic fatty liver disease (NAFLD) in mice fed a high-fat diet (HFD) and the underlying cellular and molecular mechanisms involved.

METHODS

C57BL/6 J mice were fed either a low-fat diet (LFD), an HFD, or an HFD supplemented with GGEx18 (125, 250, or 500 mg/kg of body weight/day). After 13 weeks, blood analyses, histology, immunohistochemistry, and real-time PCR were performed to assess NAFLD development in these mice.

RESULTS

Mice fed an HFD had increases in body weight, epididymal adipose tissue mass, adipocyte size, and adipose expression of inflammation-related genes compared with those fed an LFD. These increases were ameliorated in mice treated with 500 mg/kg/day GGEx18 without affecting food consumption profiles. GGEx18 not only decreased serum levels of triglycerides, free fatty acids, and alanine aminotransferase, but also decreased hepatic lipid accumulation, numbers of mast cells and α-smooth muscle actin-positive cells, and collagen levels induced by an HFD. Consistent with the histological data, the hepatic expression of lipogenesis-, inflammation-, and fibrosis-related genes was lower, while hepatic fatty acid β-oxidation-related gene expression was higher, in mice receiving GGEx18 compared to mice fed only the HFD.

DISCUSSION AND CONCLUSION

These results indicate that GGEx18 attenuates visceral obesity and NAFLD, in part by altering the expression of genes involved in hepatic steatosis and fibroinflammation in HFD-induced obese mice. These findings suggest that GGEx18 may be effective for preventing and treating NAFLD associated with visceral obesity.