Natural History of Nonalcoholic Fatty Liver Disease

PGE2 synthesis and signaling in the liver physiology and pathophysiology: An update

The liver plays a central role in systemic metabolism and drug degradation. However, it is highly susceptible to damage due to various factors, including metabolic imbalances, excessive alcohol consumption, viral infections, and drug influences. These factors often result in conditions such as fatty liver, hepatitis, and acute or chronic liver injury. Failure to address these injuries could promptly lead to the development of liver cirrhosis and potentially hepatocellular carcinoma (HCC). Prostaglandin E2 (PGE2) is a metabolite of arachidonic acid that belongs to the class of polyunsaturated fatty acids (PUFA) and is synthesized via the cyclooxygenase (COX) pathway. By binding to its G protein coupled receptors (i.e., EP1, EP2, EP3 and EP4), PGE2 has a wide range of physiological and pathophysiology effects, including pain, inflammation, fever, cardiovascular homeostasis, etc. Recently, emerging studies showed that PGE2 plays an indispensable role in liver health and disease. This review focus on the research progress of the role of PGE2 synthase and its receptors in liver physiological and pathophysiological processes and discuss the possibility of developing liver protective drugs targeting the COXs/PGESs/PGE2/EPs axis.

Redox remodeling of central metabolism as a driving force for cellular protection, proliferation, differentiation, and dysfunction

The production of reactive oxygen species (ROS) is elevated via metabolic hyperactivation in response to a variety of stimuli such as growth factors and inflammation. Tolerable amounts of ROS moderately inactivate enzymes via oxidative modification, which can be reversed back to the native form in a redox-dependent manner. The excessive production of ROS, however, causes cell dysfunction and death. Redox-reactive enzymes are present in primary metabolic pathways such as glycolysis and the tricarboxylic acid cycle, and these act as floodgates for carbon flux. Oxidation of a specific form of cysteine inhibits glyceraldehyde-3-phosphate dehydrogenase, which is reversible, and causes an accumulation of upstream intermediary compounds that increases the flux of glucose-6-phosphate to the pentose phosphate pathway. These reactions increase the NADPH and ribose-5-phosphate that are available for reductive reactions and nucleotide synthesis, respectively. On the other hand, oxidative inactivation of mitochondrial aconitase increases citrate, which is then recruited to synthesize fatty acids in the cytoplasm. Decreases in the use of carbohydrate for ATP production can be compensated via amino acid catabolism, and this metabolic change makes nitrogen available for nucleic acid synthesis. Coupling of the urea cycle also converts nitrogen to urea and polyamine, the latter of which supports cell growth. This metabolic remodeling stimulates the proliferation of tumor cells and fibrosis in oxidatively damaged tissues. Oxidative modification of these enzymes is generally reversible in the early stages of oxidizing reactions, which suggests that early treatment with appropriate antioxidants promotes the maintenance of natural metabolism.

Exploring the impact of lipid droplets on the evolution and progress of hepatocarcinoma

Over the past 10 years, the biological role of lipid droplets (LDs) has gained significant attention in the context of both physiological and pathological conditions. Considerable progress has been made in elucidating key aspects of these organelles, yet much remains to be accomplished to fully comprehend the myriad functions they serve in the progression of hepatic tumors. Our current perception is that LDs are complex and active structures managed by a distinct set of cellular processes. This understanding represents a significant paradigm shift from earlier perspectives. In this review, we aim to recapitulate the function of LDs within the liver, highlighting their pivotal role in the pathogenesis of metabolic dysfunction-associated steatotic liver disease (MASLD) (Hsu and Loomba, 2024) and their contribution to the progression towards more advanced pathological stages up to hepatocellular carcinoma (HC) (Farese and Walther, 2009). We are aware of the molecular complexity and changes occurring in the neoplastic evolution of the liver. Our attempt, however, is to summarize the most important and recent roles of LDs across both healthy and all pathological liver states, up to hepatocarcinoma. For more detailed insights, we direct readers to some of the many excellent reviews already available in the literature (Gluchowski et al., 2017; Hu et al., 2020; Seebacher et al., 2020; Paul et al., 2022).

Remission of nonalcoholic steatohepatitis after bariatric surgery: a single referral center cohort study

BACKGROUND

Obesity is associated with nonalcoholic steatohepatitis (NASH), which leads to an increased rate of primary liver cancers, cirrhosis, and decreased life expectancy. Metabolic/bariatric surgery (MBS) determines long-term weight loss and the resolution of obesity-related medical problems.

OBJECTIVE

The aim of this study was to evaluate the impact of MBS on liver histologic features in individuals with obesity.

SETTING

Tertiary referral university hospital.

METHODS

We retrospectively analyzed data on 37 patients undergoing MBS from a prospectively held database. All patients had a liver biopsy at the time of MBS and a second liver biopsy in case of further surgery or for NASH follow-up. Eighteen patients had NASH on the first liver biopsy. The primary endpoint was the resolution of steatohepatitis without worsening of fibrosis on the second liver biopsy. Secondary endpoints were the evolution of liver steatosis, hepatocyte ballooning, nonalcoholic fatty liver disease activity score, and biochemical parameters from the time of the first to the second liver biopsy.

RESULTS

Fifteen (83.3%) patients had significant resolution of steatohepatitis (P < .001) without fibrosis worsening. There was a statistically significant improvement of all blood tests except for low-density lipoprotein, alkaline phosphatases, and bilirubinemia. The Homeostatic Model Assessment (HOMA) index was significantly improved after MBS (P < .001), and circulating insulin and leptin concentrations were significantly reduced. Mean weight loss was 47 kg, with a 16.6 kg/m2 body mass index reduction and a % of total weight loss (%TWL) of 40.3 ±14% from the moment of MBS to the last follow-up.

CONCLUSION

MBS is effective in determining NASH regression without fibrosis worsening and in reducing HOMA index and leptin and insulin concentrations.

Targeting hepatic ceruloplasmin mitigates nonalcoholic steatohepatitis by modulating bile acid metabolism

Nonalcoholic steatohepatitis (NASH) is a condition that progresses from nonalcoholic fatty liver disease (NAFLD) and is characterized by hepatic fat accumulation, inflammation, and fibrosis. It has the potential to develop into cirrhosis and liver cancer, and currently no effective pharmacological treatment is available. In this study, we investigate the therapeutic potential of targeting ceruloplasmin (Cp), a copper-containing protein predominantly secreted by hepatocytes, for treating NASH. Our result show that hepatic Cp is remarkedly upregulated in individuals with NASH and the mouse NASH model. Hepatocyte-specific Cp ablation effectively attenuates the onset of dietary-induced NASH by decreasing lipid accumulation, curbing inflammation, mitigating fibrosis, and ameliorating liver damage. By employing transcriptomics and metabolomics approaches, we have discovered that hepatic deletion of Cp brings about remarkable restoration of bile acid (BA) metabolism during NASH. Hepatic deletion of Cp effectively remodels BA metabolism by upregulating Cyp7a1 and Cyp8b1, which subsequently leads to enhanced BA synthesis and notable alterations in BA profiles. In conclusion, our studies elucidate the crucial involvement of Cp in NASH, highlighting its significance as a promising therapeutic target for the treatment of this disease.

Mechanisms of Lipid Droplet Accumulation in Steatotic Liver Diseases

The steatotic diseases of metabolic dysfunction-associated steatotic liver disease (MASLD), alcohol-associated liver disease (ALD), and chronic hepatitis C (HCV) account for the majority of liver disease prevalence, morbidity, and mortality worldwide. While these diseases have distinct pathogenic and clinical features, dysregulated lipid droplet (LD) organelle biology represents a convergence of pathogenesis in all three. With increasing understanding of hepatocyte LD biology, we now understand the roles of LD proteins involved in these diseases but also how genetics modulate LD biology to either exacerbate or protect against the phenotypes associated with steatotic liver diseases. Here, we review the history of the LD organelle and its biogenesis and catabolism. We also review how this organelle is critical not only for the steatotic phenotype of liver diseases but also for their advanced phenotypes. Finally, we summarize the latest attempts and challenges of leveraging LD biology for therapeutic gain in steatotic diseases. In conclusion, the study of dysregulated LD biology may lead to novel therapeutics for the prevention of disease progression in the highly prevalent steatotic liver diseases of MASLD, ALD, and HCV.

Nonalcoholic fatty liver disease and type 2 diabetes: an observational and Mendelian randomization study

Introduction

Nonalcoholic fatty liver disease (NAFLD) and type 2 diabetes mellitus (T2DM) are both chronic multisystem diseases that cause tremendous health burdens worldwide. Previous epidemiological studies have found a bidirectional relationship between these two diseases; however, their causality remains largely unknown. We aim to examine the causal relationship between NAFLD and T2DM.

Methods

The observational analysis included 2,099 participants from the SPECT-China study and 502,414 participants from the UK Biobank. Logistic regression and Cox regression models were used to examine the bidirectional association between NAFLD and T2DM. Two-sample Mendelian randomization (MR) analyses were conducted to investigate the causal effects of the two diseases using summary statistics of genome-wide association studies from the UK Biobank for T2DM and the FinnGen study for NAFLD.

Results

During the follow-up, 129 T2DM cases and 263 NAFLD cases were observed in the SPECT-China study, and 30,274 T2DM cases and 4,896 NAFLD cases occurred in the UK Biobank cohort. Baseline NAFLD was associated with an increased risk of incident T2DM in both studies (SPECT-China: OR: 1.74 (95% confidence interval (CI): 1.12-2.70); UK Biobank: HR: 2.16 (95% CI: 1.82-2.56)), while baseline T2DM was associated with incident NAFLD in the UK Biobank study only (HR: 1.58). Bidirectional MR analysis showed that genetically determined NAFLD was significantly associated with an increased risk of T2DM (OR: 1.003 (95% CI: 1.002-1.004, p< 0.001)); however, there was no evidence of an association between genetically determined T2DM and NAFLD (OR: 28.1 (95% CI: 0.7-1,143.0)).

Conclusions

Our study suggested the causal effect of NAFLD on T2DM development. The lack of a causal association between T2DM and NAFLD warrants further verification.

Hepatoprotective effect of dihydroxy piperlongumine in high cholesterol-induced non-alcoholic fatty liver disease zebrafish via antioxidant activity

Non-alcoholic fatty liver disease (NAFLD) and non-alcoholic steatohepatitis (NASH) are a growing epidemic and the most common liver diseases. Consumption of a western diet with high fats alters redox status, induces inflammation, and impairs the physiological function of hepatocytes. However, the pharmacological market lacks anti-NAFLD/NASH drugs. Long pepper (Piper longum L) is used in traditional Mongolian medicine for treating hyperlipidemia. Piperlongumine (PL) is a bioactive compound of Piper longum L, which usually possesses anticancer activities due to its ROS elevation property. However, when PL was demethylated they behave as an antioxidant. Previously, we found dihydroxy piperlongumine (DHPL) possesses high antioxidant activity among the hydroxy piperlongumines, which makes us curious to reveal the anti-NAFLD effect. A high-cholesterol diet (HCD) was chosen to induce NAFLD zebrafish model, and the antioxidant and lipid-lowering effects of DHPL were evaluated. Histological alterations of NAFLD were also scored along with gene expression to explore the molecular mechanism. DHPL reduced lipid accumulation in both short-term and long-term feeding trials. DHPL increases antioxidant activity and lipid-lowering gene expression and decreases hepatic triglyceride, oxidative stress, and lipogenic genes. In conclusion, DHPL halted the progression of HCD-induced NAFLD in the zebrafish model.

Polyunsaturated fatty acids drive neutrophil extracellular trap formation in nonalcoholic steatohepatitis

Non-alcoholic steatohepatitis (NASH) is the hepatic manifestation of metabolic syndrome. Non-resolving inflammation, triggered by sustained accumulation of lipids, is an important driving force of NASH. Thus, unveiling metabolic immune regulation could help better understand the pathology and intervention of NASH. In this study, we found the recruitment of neutrophils is an early inflammatory event in NASH mice, following the formation of neutrophil extracellular traps (NETs). NET is an initiating factor which exacerbates inflammatory responses in macrophages. Inhibition of NETs using DNase I significantly alleviated inflammation in NASH mice. We further carried out a metabolomic study to identify possible metabolic triggers of NETs, and linoleic acid (LA) metabolic pathway was the most altered pathway. We re-analyzed published clinical data and validated that LA metabolism was highly correlated with NASH. Consistently, both LA and γ-linolenic acid (GLA) were active in triggering NETs formation by oxidative burst. Furthermore, we identified silybin, a hepatoprotective agent, as a potent NETosis inhibitor, which effectively blocked NETs formation both in vitro and in vivo. Together, this study not only provide new insights into metabolism-immune causal link in NASH progression, but also demonstrate silybin as an important inhibitor of NETs and its therapeutical potential in treating NETosis-related diseases.

Sesamin Attenuates Obesity-Associated Nonalcoholic Steatohepatitis in High-Fat and High-Fructose Diet-Fed Mice

This study explored the effects of sesamin on nonalcoholic steatohepatitis (NASH). High-fat and high-fructose diet-fed mice supplemented with or without sesamin. The results suggested that sesamin-treated mice lost body weight and fat tissue weight, had lower levels of serum metabolic parameters, and insulin resistance was mitigated. Histological examinations showed that sesamin treatment mitigated the progression of hepatic steatosis, and inflammation. In addition, sesamin enhanced hepatic antioxidant capacity, and decreased the activations of hepatic c-jun N-terminal kinase, inhibitor of kappa B kinase α, and insulin receptor substrate 1 as well as hepatic interleukin-6 and tumor necrosis factor-alpha levels. Further experiments indicated that sesamin treatment downregulated GRP78 and phospho-inositol-requiring enzyme 1 (IRE1) expression, and upregulated x-box binding protein 1 (XBP1) expression in hepatic tissue. The aforementioned results suggest that sesamin alleviates obesity-associated NASH, which might be linked to the effect of sesamin on the regulation of the hepatic endoplasmic reticulum stress-IRE1/XBP1 pathway. Thus, sesamin may be a good food functional ingredient in the treatment of obesity-associated NASH.

Diabetes mellitus is not associated with worse short term outcome in patients older than 65 years old post-liver transplantation

BACKGROUND

Non-alcoholic fatty liver disease is a global health care challenge and a leading indication of liver transplantation (LT). Hence, more patients with diabetes mellitus (DM) are undergoing LT, especially, above the age of 65.

AIM

To evaluate the impact of DM on short-term outcomes post-LT in patients over the age of 65.

METHODS

We collected data of patients who underwent LT from January 2001 until December 2019 using our electronic medical record. We assessed the impact of DM on short-term outcomes, one-year, post-LT based on the following variables: Survival at one year; acute cellular rejection (ACR) rates; intensive care unit (ICU) and hospital length of stay; and readmissions.

RESULTS

Total of 148 patients who are 65 year or older underwent LT during the study period. The mean age is 68.5 ± 3.3 years and 67.6% were male. The median Model for End-stage Liver Disease score at time of transplantation was 22 (6-39), 39% of patients had hepatocellular carcinoma and 77.7% underwent living donor LT. The one-year survival was similar between DM patients and others, 91%. ACR occurred in 13.5% of patients (P = 0.902). The median ICU stay is 4.5-day P = 0.023. The rates of ICU and 90-d readmission were similar (P = 0.821) and (P = 0.194), respectively.

CONCLUSION

The short-term outcome of elderly diabetic patients undergoing LT is similar to others. The presence of DM in elderly LT candidates should not discourage physicians from transplant consideration in this cohort of patients.

Protective Effects of Lactobacillus gasseri against High-Cholesterol Diet-Induced Fatty Liver and Regulation of Host Gene Expression Profiles

Fatty liver is one of the most pervasive liver diseases worldwide. Probiotics play an important role in the progression of liver disease, but their effects on host regulation are poorly understood. This study investigated the protective effects of lactobacillus gasseri (L. gasseri) against high-cholesterol diet (HCD)-induced fatty liver injury using a zebrafish larvae model. Liver pathology, lipid accumulation, oxidative stress and hepatic inflammation were evaluated to demonstrate the changes in a spectrum of hepatic injury. Moreover, multiple indexes on host gene expression profiles were comprehensively characterized by RNA screening. The results showed that treatment with L. gasseri ameliorated HCD-induced morphological and histological alterations, lipid regulations, oxidative stress and macrophage aggregation in the liver of zebrafish larvae. Furthermore, the enrichment of the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway revealed that the core pathways of L. gasseri regulation were interleukin-17 (IL-17) signaling, phosphoinositide 3-kinase (PI3K)-AKT signaling pathway, the regulation of lipolysis and adipocytes and fatty acid elongation and estrogen signaling. The genes at key junction nodes, hsp90aa1.1, kyat3, hsd17b7, irs2a, myl9b, ptgs2b, cdk21 and papss2a were significantly regulated by L. gasseri administration. To conclude, the current research extends our understanding of the protective effects of L. gasseri against fatty liver and provides potential therapeutic options for fatty liver treatment.

Management of obesity across women's life course: FIGO Best Practice Advice

Obesity is a chronic, progressive, relapsing, and treatable multifactorial, neurobehavioral disease. According to the World Health Organization, obesity affects 15% of women and has long-term effects on women's health. The focus of care in patients with obesity should be on optimizing health outcomes rather than on weight loss. Appropriate and common language, considering cultural sensitivity and trauma-informed care, is needed to discuss obesity. Pregnancy is a time of significant physiological change. Pre-, ante-, and postpartum clinical encounters provide opportunities for health optimization for parents with obesity in terms of, but not limited to, fertility and breastfeeding. Pre-existing conditions may also be identified and managed. Beyond pregnancy, women with obesity are at an increased risk for gastrointestinal and liver diseases, impaired kidney function, obstructive sleep apnea, and venous thromboembolism. Gynecological and reproductive health of women living with obesity cannot be dismissed, with accommodations needed for preventive health screenings and consideration of increased risk for gynecologic malignancies. Mental wellness, specifically depression, should be screened and managed appropriately. Obesity is a complex condition and is increasing in prevalence with failure of public health interventions to achieve significant decrease. Future research efforts should focus on interprofessional care and discovering effective interventions for health optimization.

Emerging Role of Hepatic Ketogenesis in Fatty Liver Disease

Non-alcoholic fatty liver disease (NAFLD), the most common chronic liver diseases, arise from non-alcoholic fatty liver (NAFL) characterized by excessive fat accumulation as triglycerides. Although NAFL is benign, it could progress to non-alcoholic steatohepatitis (NASH) manifested with inflammation, hepatocyte damage and fibrosis. A subset of NASH patients develops end-stage liver diseases such as cirrhosis and hepatocellular carcinoma. The pathogenesis of NAFLD is highly complex and strongly associated with perturbations in lipid and glucose metabolism. Lipid disposal pathways, in particular, impairment in condensation of acetyl-CoA derived from β-oxidation into ketogenic pathway strongly influence the hepatic lipid loads and glucose metabolism. Current evidence suggests that ketogenesis dispose up to two-thirds of the lipids entering the liver, and its dysregulation significantly contribute to the NAFLD pathogenesis. Moreover, ketone body administration in mice and humans shows a significant improvement in NAFLD. This review focuses on hepatic ketogenesis and its role in NAFLD pathogenesis. We review the possible mechanisms through which impaired hepatic ketogenesis may promote NAFLD progression. Finally, the review sheds light on the therapeutic implications of a ketogenic diet in NAFLD.

Bone morphogenetic protein 2 is a new molecular target linked to non-alcoholic fatty liver disease with potential value as non-invasive screening tool

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) is the commonest cause of chronic liver disease worldwide, being non-alcoholic steatohepatitis (NASH) its most clinically relevant form. Given the risks associated with taking a liver biopsy, the design of accurate non-invasive methods to identify NASH patients is of upmost importance. BMP2 plays a key role in metabolic homeostasis; however, little is known about its involvement in NAFLD onset and progression. This study aimed to elucidate the impact of BMP2 in NAFLD pathophysiology.

METHODS

Hepatic and circulating levels of BMP2 were quantified in serum and liver specimens from 115 biopsy-proven NAFLD patients and 75 subjects with histologically normal liver (NL). In addition, BMP2 content and release was determined in cultured human hepatocytes upon palmitic acid (PA) overload.

RESULTS

We found that BMP2 expression was abnormally increased in livers from NAFLD patients than in subjects with NL and this was reflected in higher serum BMP2 levels. Notably, we observed that PA upregulated BMP2 expression and secretion by human hepatocytes. An algorithm based on serum BMP2 levels and clinically relevant variables to NAFLD showed an AUROC of 0.886 (95%CI, 0.83-0.94) to discriminate NASH. We used this algorithm to develop SAN (Screening Algorithm for NASH): a SAN < 0.2 implied a low risk and a SAN ≥ 0.6 indicated high risk of NASH diagnosis.

CONCLUSION

This proof-of-concept study shows BMP2 as a new molecular target linked to NAFLD and introduces SAN as a simple and efficient algorithm to screen individuals at risk for NASH.

Chronic Inflammation—A Link between Nonalcoholic Fatty Liver Disease (NAFLD) and Dysfunctional Adipose Tissue

Nonalcoholic fatty liver disease (NAFLD) is a new challenge in modern medicine, due to its high prevalence in the world. The pathogenesis of NAFLD is a complex dysmetabolic process, following the “multiple-hit” hypothesis that involves hepatocytes excessive accumulation of triglycerides, insulin resistance (IR), increased oxidative stress, chronic low-grade inflammatory response and lipotoxicity. In this review, we provide an overview of the interrelation of these processes, the link between systemic and local inflammation and the role of dysfunctional adipose tissue (AT) in the NAFLD development. Multiple extrahepatic triggers of the pathophysiological mechanisms of NAFLD are described: nutritional deficiency or malnutrition, unhealthy food intake, the dysfunction of the liver–gut axis, the involvement of the mesenteric adipose tissue, the role of adipokines such as adiponectin, of food intake hormone, the leptin and leptin resistance (LR) and adipose tissue’s hormone, the resistin. In addition, a wide range of intrahepatic players are involved: oxidative stress, fatty acid oxidation, endoplasmic reticulum stress, mitochondrial dysfunction, resident macrophages (Kupffer cells), neutrophils, dendritic cells (DCs), B and T lymphocytes contributing to the potential evolution of NAFLD to nonalcoholic steatohepatitis (NASH). This interdependent approach to complex dysmetabolic imbalance in NAFLD, integrating relevant studies, could contribute to a better clarification of pathogenesis and consequently the development of new personalized treatments, targeting de novo lipogenesis, chronic inflammation and fibrosis. Further studies are needed to focus not only on treatment, but also on prevention strategy in NAFLD.

Prevalence of nonalcoholic fatty liver disease using noninvasive techniques among children, adolescents, and youths living with HIV

OBJECTIVE

The prevalence of subclinical liver abnormalities is high among people with HIV, but data regarding perinatally HIV-infected children and adolescents (PHIV) are scarce. Noninvasive image techniques offer an opportunity to address nonalcoholic fatty liver disease (NAFLD) in a population in which the scores validated for adults have not been tested.

DESIGN

Prospective cross-sectional study including PHIV and uninfected controls.

METHODS

Noninvasive imaging techniques for the diagnosis of NAFLD and/or fibrosis were performed, and four scores to predict NAFLD were evaluated.

RESULTS

Seventy-six participants (59.2% women) with a median of 19 years old (interquartile range: 15.5-25.6) were included, 38 were PHIV and 38 were age and sex-matched controls. All HIV participants were on ART at the moment of inclusion, and 86.8% were virologically suppressed. A total of 11 PHIV and three controls were diagnosed with NAFLD (28.9% vs. 7.9%; P = 0.02) by noninvasive imaging techniques. The performance of scores based on clinical and analytical parameters was very poor. Although nonsignificant, overweight was more common among participants with NAFLD, who had a significantly higher BMI. Differences in HIV-related parameters between the groups were nonsignificant, except for the CD4+/CD8+ T-cells ratio, decreased among PHIV diagnosed with NAFLD (P = 0.04).

CONCLUSIONS

The prevalence of NAFLD was high (28.9%) among PHIV, and only partially explained by overweight and metabolic syndrome defining factors. The scores based on clinical and analytical parameters did not accurately identify participants at risk. Therefore, liver ultrasound assessment should be considered for the screening of NAFLD among PHIV in routine clinical practice.

Genome-wide DNA methylation profiling in nonalcoholic fatty liver reveals predictive aberrant methylation in PRKCE and SEC14L3 promoters

BACKGROUND

Optimal non-invasive biomarkers for diagnosis and treatment of nonalcoholic fatty liver disease (NAFLD) remain to be identified.

AIMS

To identify potential DNA methylation biomarkers for NAFLD.

METHODS

Genome-wide DNA methylation profiling was performed to identify differentially methylated CpG sites in peripheral blood leukocytes. Differentially methylated regions were validated using the MassCLEAVE assay. The expression levels of candidate genes were explored by Gene Expression Omnibus database.

RESULTS

The hypomethylation of PRKCE CpG 4.5 and CpG 18.19 was associated with nonalcoholic fatty liver (NAFL), the odds ratio (OR) and 95% confidence interval (CI) were 0.129 (0.026-0.639) and 0.231 (0.069-0.768). The methylation level of CpG 1.2 and average methylation level of SEC14L3 were correlated with NAFL, with OR (95% CI) being 0.283 (0.093-0.865) and 0.264 (0.087-0.799). PRKCE CpG 4.5 and cg17802464 of SEC14L3 were correlated with body mass index, waist circumference, total triglyceride, high-density lipoprotein cholesterol, alanine aminotransferase and aspartate aminotransferase. All selected datasets showed high expression levels of PRKCE and SEC14L3 in patients with NAFLD.

CONCLUSIONS

Our findings suggest that the hypomethylation of PRKCE and SEC14L3 promoters represent attractive biomarkers for NAFLD. Further studies are warranted to validate these biomarkers as molecular tools for diagnosis of NAFLD and therapeutic targets.

A new perspective on NAFLD: Focusing on lipid droplets

Lipid droplets (LDs) are complex and metabolically active organelles. They are composed of a neutral lipid core surrounded by a monolayer of phospholipids and proteins. LD accumulation in hepatocytes is the distinctive characteristic of non-alcoholic fatty liver disease (NAFLD), which is a chronic, heterogeneous liver condition that can progress to liver fibrosis and hepatocellular carcinoma. Though recent research has improved our understanding of the mechanisms linking LD accumulation to NAFLD progression, numerous aspects of LD biology are either poorly understood or unknown. In this review, we provide a description of several key mechanisms that contribute to LD accumulation in hepatocytes, favouring NAFLD progression. First, we highlight the importance of LD architecture and describe how the dysregulation of LD biogenesis leads to endoplasmic reticulum stress and inflammation. This is followed by an analysis of the causal nexus that exists between LD proteome composition and LD degradation. Finally, we describe how the increase in size of LDs causes activation of hepatic stellate cells, leading to liver fibrosis and hepatocellular carcinoma. We conclude that acquiring a more sophisticated understanding of LD biology will provide crucial insights into the heterogeneity of NAFLD and assist in the development of therapeutic approaches for this liver disease.

Synthesis and Spectroscopic Characterization of Dapagliflozin/Zn (II), Cr (III) and Se (IV) Novel Complexes That Ameliorate Hepatic Damage, Hyperglycemia and Oxidative Injury Induced by Streptozotocin-Induced Diabetic Male Rats and Their Antibacterial Activity

Diabetes mellitus (DM) causes an imbalance in the oxidative status of the human body. Three novel Dapagliflozin (Dapg) Zn (II), Cr (III) and Se (IV) complexes were prepared and characterized by elemental analysis, IR, electronic spectra, magnetic susceptibility, scanning electron microscopy (SEM) and X-ray diffraction. The molar conductance values confirmed the non-electrolytic nature of the Dapg complexes. According to spectral data, Dapg acts as a bidentate ligand. The thermal analyses of the complexes were studied using the DSC technique. The surface morphology and particle sizes of the Dapg complexes were investigated using SEM and XRD. XRD confirmed the crystalline structure for the complexity. This study investigated the effect of novel metal complexes of Dapg with the metals Zn (II), Cr (III) and Se (IV) on oxidative injury and tissue damage in the hepatic tissue of streptozotocin (STZ)-induced diabetic male rats. DM was experimentally induced in male rats. The diabetic rats received Dapg, Dapg/Zn, Dapg/Cr and Dapg/Se orally for 30 successive days. Male rats exposed to STZ showed multi-histopathological alterations in their hepatic tissue, including inflammatory and structural changes. STZ elevated oxidative stress markers in the hepatic tissue and lowered the antioxidant defense enzymes. Supplementation of Dapg with Zn, Cr or Se novel complexes significantly prevented hepatic injury and suppressed the generation of reactive oxygen species. The Dapg/Zn complex was highly effective against Bacillus subtilis and Streptococcus penumonia, while Dapg/Cr was highly effective against Escherichia coli and Pseudomonas aeruginosa, and Dapg/Se was highly effective against Staphylococcus aureas. In conclusion, Dapg novel metal complexes with Zn, Cr or Se protect against oxidative injury and the pathophysiological and bacterial complications of DM and hepatic tissue injury. The Dapg novel metal complexes improved hepatic functions, reduced blood glucose levels and enhanced the levels of antioxidant defense enzymes in diabetic male rats.

Cadmium Exposure in Young Adulthood Is Associated with Risk of Nonalcoholic Fatty Liver Disease in Midlife

BACKGROUND

Studies have suggested that cadmium (Cd) may be involved in the etiology of nonalcoholic fatty liver disease (NAFLD), but available data in human is sparse.

AIMS

We aimed to examine Cd exposure in young adulthood in relation to prevalent NAFLD in midlife among American adults.

METHODS

This study included 2446 participants from the Coronary Artery Risk Development in Young Adults study with toenail Cd measurement at exam year 2 (baseline) and computed tomography quantification of liver fat at exam year 25. Toenail Cd concentrations were considered as a reliable marker of long-term exposure. NAFLD was defined if liver attenuation < 51 Hounsfield units after excluding other possible causes of liver fat. Multivariable-adjusted logistic regression models were used to estimate the odds ratio of NAFLD by Cd exposure.

RESULTS

Median toenail Cd concentration was 8.2 ppb (inter-quartile range 4.3-18.6 ppb). After 23 years from baseline, 580 participants with prevalent NAFLD (24% prevalence) in midlife were identified. Compared with individuals in the lowest quartile, those in the highest quartile of toenail Cd had a significantly higher odds of NAFLD (OR: 1.43, 95% CI: 1.02, 1.99, P for trend: 0.04) after adjustment for demographics, socioeconomics, major lifestyle factors, and baseline levels of body mass index, lipids, and fasting insulin. The association was not significantly modified by race, sex, BMI, or smoking status at baseline.

CONCLUSIONS

Toenail Cd concentration was associated with a higher odds of prevalent NAFLD23 years later in life in this cohort of US general population.

Is there a role of lipid-lowering therapies in the management of fatty liver disease?

Atherogenic dyslipidemia is characterized by increased triglyceride-rich lipoproteins and low high-density lipoprotein cholesterol concentrations. It is highly prevalent in non-alcoholic fatty liver disease (NAFLD) and contributes to the increased cardiovascular risk associated with this condition. Alongside insulin resistance it plays an important pathogenetic role in NAFLD/non-alcoholic steatohepatitis (NASH) development and progression. It has been shown that cholesterol-lowering reduces cardiovascular risk more in NAFLD vs non-NAFLD high-risk individuals. This evidence highlights the importance of effective lipid modulation in NAFLD. In this narrative review the effects of the most commonly used lipid-lowering therapies on liver outcomes alongside their therapeutic implications in NAFLD/NASH are critically discussed. Preclinical and clinical evidence suggests that statins reduce hepatic steatosis, inflammation and fibrosis in patients with NAFLD/NASH. Most data are derived from observational and small prospective clinical studies using changes in liver enzyme activities, steatosis/fibrosis scores, and imaging evidence of steatosis as surrogates. Also, relevant histologic benefits were noted in small biopsy studies. Atorvastatin and rosuvastatin showed greater benefits, whereas data for other statins are scarce and sometimes conflicting. Similar studies to those of statins showed efficacy of ezetimibe against hepatic steatosis. However, no significant anti-inflammatory and anti-fibrotic actions of ezetimibe have been shown. Preclinical studies showed that fibrates through peroxisome proliferator-activated receptor (PPAR)α activation may have a role in NAFLD prevention and management. Nevertheless, no relevant benefits have been noted in human studies. Species-related differences in PPARα expression and its activation responsiveness may help explain this discrepancy. Omega-3 fatty acids reduced hepatic steatosis in numerous heterogeneous studies, but their benefits on hepatic inflammation and fibrosis have not been established. Promising preliminary data for the highly purified eicosapentaenoic acid require further confirmation. Observational studies suggest that proprotein convertase subtilisin/kexin9 inhibitors may also have a role in the management of NAFLD, though this needs to be established by future prospective studies.

Fasting, Nutrition and Weight Loss: An Approach to Refine Non-Alcoholic Fatty Liver Disease

Non-alcoholic fatty liver disease (NAFLD) is considered as one of the most common causes of chronic liver disease. It includes a group of conditions associated with fat deposition in liver cells. Also, NAFLD is strongly associated with obesity and insulin resistance (IR). Until now, there is no pharmacological treatment validated for this disease. Fasting, nutritional intervention, and weight loss can be considered the first line in treating hepatic steatosis. This review is based on the scientific evidence showing the results of these interventions in the past years. The results include fasting and nutritional support for NAFLD treatment in humans. In clinical trials and cohort studies, an increase in hepatic fat content was correlated with a weight loss of at least 7% and a diet resembling the Mediterranean diet (MD) improving hepatic biomarkers and histological regression of NAFLD. Fasting is a dietary approach known to improve the lipid profile in healthy and obese populations by decreasing overall cholesterol, triglycerides, LDL, and increasing HDL. Bariatric surgery helps improve liver fat content in patients with serious health problems due to overweight.

Potential Natural Compounds for the Prevention and Treatment of Nonalcoholic Fatty Liver Disease: A Review on Molecular Mechanisms

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) is a kind of metabolic stress-induced liver injury closely related to insulin resistance and genetic susceptibility, and there is no specific drug for its clinical treatment currently. In recent years, a large amount of literature has reported that many natural compounds extracted from traditional Chinese medicine (TCM) can improve NAFLD through various mechanisms. According to the latest reports, some emerging natural compounds have shown great potential to improve NAFLD but are seldom used clinically due to the lacking special research.

PURPOSE

This paper aims to summarize the molecular mechanisms of the potential natural compounds on improving NAFLD, thus providing a direction and basis for further research on the pathogenesis of NAFLD and the development of effective drugs for the prevention and treatment of NAFLD.

METHODS

By searching various online databases, such as Web of Science, SciFinder, PubMed, and CNKI, NAFLD and these natural compounds were used as the keywords for detailed literature retrieval.

RESULTS

The pathogenesis of NAFLD and the molecular mechanisms of the potential natural compounds on improving NAFLD have been reviewed.

CONCLUSION

Many natural compounds from traditional Chinese medicine have a good prospect in the treatment of NAFLD, which can serve as a direction for the development of anti-NAFLD drugs in the future.

Preventive and therapeutic role of betaine in liver disease: A review on molecular mechanisms

Betaine is a kind of water-soluble quaternary amine-type alkaloid widely existing in food, such as wheat germ, beet, spinach, shrimp and wolfberry. As an important methyl donor and osmotic pressure regulator in human body, betaine plays an important role in a variety of physiological activities. In recent years, a large number of literatures have shown that betaine has good preventive and therapeutic effects on many liver diseases, including chemical or drug-induced liver injury, nonalcoholic fatty liver disease, alcoholic fatty liver disease, liver fibrosis, hepatitis B and hepatitis C. Therefore, by searching the databases of Web of Science, PubMed, SciFinder and CNKI, this paper has summarized the molecular mechanisms of betaine in improving liver diseases. The results show that the improvement of liver diseases by betaine is closely related to a variety of molecular mechanisms, including inhibition of inflammatory response, improvement of insulin resistance, reduction of endoplasmic reticulum stress, alleviation of liver oxidative stress, increase of autophagy, remodeling of intestinal flora and regulation of epigenetic modification. More importantly, nuclear transcription factor kappa (NF-κB), AMP-activated protein kinase (AMPK), peroxisome proliferator-activated receptor α/γ (PPAR-α/γ), liver X receptor α (LXRα), protein kinase B (Akt), toll-like receptor 4 (TLR4) and cysteinyl aspartate specific proteinase-3 (Caspase-3) signaling pathways are considered as important molecular targets for betaine to improve liver diseases. These important findings will provide a direction and basis for further exploring the pathogenesis of various liver diseases and tapping the potential of betaine in the clinical treatment.

The Ameliorative Effects of Saikosaponin in Thioacetamide-Induced Liver Injury and Non-Alcoholic Fatty Liver Disease in Mice

Liver disorders are a major health concern. Saikosaponin-d (SSd) is an effective active ingredient extracted from Bupleurum falcatum, a traditional Chinese medicinal plant, with anti-inflammatory and antioxidant properties. However, its hepatoprotective properties and underlying mechanisms are unknown. We investigated the effects and underlying mechanisms of SSd treatment for thioacetamide (TAA)-induced liver injury and high-fat-diet (HFD)-induced non-alcoholic fatty liver disease (NAFLD) in male C57BL/6 mice. The SSd group showed significantly higher food intake, body weight, and hepatic antioxidative enzymes (catalase (CAT), glutathione peroxidase (GPx), and superoxide dismutase (SOD)) and lower hepatic cyclooxygenase-2 (COX-2), serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), interleukin (IL)-1β, tumor necrosis factor (TNF)-α, and fibroblast growth factor-21 (FGF21) compared with controls, as well as reduced expression of inflammation-related genes (nuclear factor kappa B (NF-κB) and inducible nitric oxide synthase (iNOS)) messenger RNA (mRNA). In NAFLD mice, SSd reduced serum ALT, AST, triglycerides, fatty acid–binding protein 4 (FABP4) and sterol regulatory element–binding protein 1 (SREBP1) mRNA, and endoplasmic reticulum (ER)-stress-related proteins (phosphorylated eukaryotic initiation factor 2α subunit (p-eIF2α), activating transcription factor 4 (ATF4), and C/EBP homologous protein (CHOP). SSd has a hepatoprotective effect in liver injury by suppressing inflammatory responses and acting as an antioxidant.

Sesamol supplementation alleviates nonalcoholic steatohepatitis and atherosclerosis in high-fat, high carbohydrate and high-cholesterol diet-fed rats

Sesamol, a major ingredient in sesame seeds (Sesamum indicum L.) and its oil, is considered a powerful functional food ingredient. However, few studies have investigated its effects on high-fat, high carbohydrate and high-cholesterol (HF-HCC) diet-induced nonalcoholic steatohepatitis (NASH) complicated with atherosclerosis. The present study elucidates the protective effects of sesamol against NASH and atherosclerosis in HF-HCC diet-fed rats. Sprague-Dawley rats were supplemented with or without sesamol in drinking water (0.05 mg mL^-1, 0.1 mg mL^-1 and 0.2 mg mL^-1) from the beginning to end. At the end of the experiment, sesamol supplementation suppressed HF-HCC diet-induced body weight gain and increased absolute liver and adipose tissue weights in rats. Serum biochemical analyses showed that sesamol supplementation improved HF-HCC diet-induced metabolism disorders and damaged vascular endothelial function. Histological examinations displayed that dietary sesamol not only alleviated hepatic balloon degeneration, steatosis, inflammation and fibrosis, but also mitigated lipid accumulation and fibrous elements in the aorta arch in HF-HCC diet-fed rats. In addition, sesamol supplementation inhibited hepatic NOD-like receptor protein 3 (NLRP3) expression and ERS-IRE1 signaling pathway activation. Moreover, sesamol treatment decreased uric acid levels both in serum and the liver by its effect on the inhibition of xanthine oxidase (XO) activity and/or its expression, which might be closely associated with the inhibitions of NLRP3 expression and ERS-IRE1 signaling pathway activation in HF-HCC diet-fed rats. These findings demonstrated that sesamol alleviated NASH and atherosclerosis in HF-HCC diet-fed rats, and may be a potent dietary supplement for protection against these diseases.

Association of dietary fat intake and hepatocellular carcinoma among US adults

BACKGROUND AND AIMS

The role of dietary fat consumption in the etiology of hepatocellular carcinoma (HCC) remains unclear. We investigated the associations of total fat and fatty acids with risk of HCC among US adults in a hospital-based case-control study.

METHODS

We analyzed data from 641 cases and 1034 controls recruited at MD Anderson Cancer Center during 2001-2018. Cases were new patients with a pathologically or radiologically confirmed diagnosis of HCC; controls were cancer-free spouses of patients with cancers other than gastrointestinal, lung, liver, or head and neck. Cases and controls were frequency-matched by age and sex. Dietary intake was assessed using a validated food frequency questionnaire. Odds ratios (ORs) and corresponding confidence intervals (CIs) were computed using unconditional logistic regression with adjustment for major HCC risk factors, including hepatitis B virus and hepatitis C virus infection.

RESULTS

Monounsaturated fatty acid (MUFA) intake was inversely associated with HCC risk (highest vs. lowest tertile: OR, 0.49; 95% CI, 0.33-0.72). Total polyunsaturated fatty acid (PUFA) intake was directly associated with HCC risk (highest vs. lowest tertile: OR, 1.82; 95% CI, 1.23-2.70). Omega-6 PUFA was directly associated with HCC risk (highest vs. lowest tertile: OR 2.29; 95% CI, 1.52-3.44). Long-chain omega-3 PUFA (eicosapentaenoic acid and docosahexaenoic acid) intake was also inversely associated with HCC risk (highest vs. lowest tertile: OR, 0.50; 95% CI, 0.33-0.70). No association was observed for saturated fat and HCC risk.

CONCLUSION

Our findings support a direct association of omega-6 PUFA intake with HCC and an inverse association of MUFA and long-chain omega-3 PUFA intake with HCC.

Oxidative stress in obesity-associated hepatocellular carcinoma: sources, signaling and therapeutic challenges

Obesity affects more than 650 million individuals worldwide and is a well-established risk factor for the development of hepatocellular carcinoma (HCC). Oxidative stress can be considered as a bona fide tumor promoter, contributing to the initiation and progression of liver cancer. Indeed, one of the key events involved in HCC progression is excessive levels of reactive oxygen species (ROS) resulting from the fatty acid influx and chronic inflammation. This review provides insights into the different intracellular sources of obesity-induced ROS and molecular mechanisms responsible for hepatic tumorigenesis. In addition, we highlight recent findings pointing to the role of the dysregulated activity of BCL-2 proteins and protein tyrosine phosphatases (PTPs) in the generation of hepatic oxidative stress and ROS-mediated dysfunctional signaling, respectively. Finally, we discuss the potential and challenges of novel nanotechnology strategies to prevent ROS formation in obesity-associated HCC.

Sterol O-acyltransferase 2 chaperoned by apolipoprotein J facilitates hepatic lipid accumulation following viral and nutrient stresses

The risks of non-alcoholic fatty liver disease (NAFLD) include obese and non-obese stresses such as chronic hepatitis C virus (HCV) infection, but the regulatory determinants remain obscure. Apolipoprotein J (ApoJ) served as an ER-Golgi contact-site chaperone near lipid droplet (LD), facilitating HCV virion production. We hypothesized an interplay between hepatic ApoJ, cholesterol esterification and lipid deposit in response to NAFLD inducers. Exposures of HCV or free-fatty acids exhibited excess LDs along with increased ApoJ expression, whereas ApoJ silencing alleviated hepatic lipid accumulation. Both stresses could concomitantly disperse Golgi, induce closer ApoJ and sterol O-acyltransferase 2 (SOAT2) contacts via the N-terminal intrinsically disordered regions, and increase cholesteryl-ester. Furthermore, serum ApoJ correlated positively with cholesterol and low-density lipoprotein levels in normal glycaemic HCV patients, NAFLD patients and in mice with steatosis. Taken together, hepatic ApoJ might activate SOAT2 to supply cholesteryl-ester for lipid loads, thus providing a therapeutic target of stress-induced steatosis.

5-Bis-(2,6-difluoro-benzylidene) Cyclopentanone Acts as a Selective 11β-Hydroxysteroid Dehydrogenase one Inhibitor to Treat Diet-Induced Nonalcoholic Fatty Liver Disease in Mice

Background: 11β-Hydroxysteroid dehydrogenase one is responsible for activating inert glucocorticoid cortisone into biologically active cortisol in humans and may be a novel target for the treatment of nonalcoholic fatty liver disease.

Methods: A series of benzylidene cyclopentanone derivatives were synthesized, and the selective inhibitory effects on rat, mouse and human 11β-hydroxysteroid dehydrogenase one and two were screened. The most potent compound [5-bis-(2,6-difluoro-benzylidene)-cyclopentanone] (WZS08), was used to treat nonalcoholic fatty liver disease in mice fed a high-fat-diet for 100 days.

Results: WZS08 was the most potent inhibitor of rat, mouse, and human 11β-hydroxysteroid dehydrogenase 1, with half maximum inhibitory concentrations of 378.0, 244.1, and 621.1 nM, respectively, and it did not affect 11β-hydroxysteroid dehydrogenase two at 100 μM. When mice were fed WZS08 (1, 2, and 4 mg/kg) for 100 days, WZS08 significantly lowered the serum insulin levels and insulin index at 4 mg/kg. WZS08 significantly reduced the levels of serum triglycerides, cholesterol, low-density lipoprotein, and hepatic fat ratio at low concentration of 1 mg/kg. It down-regulated Plin2 expression and up-regulated Fabp4 expression at low concentration of 1 mg/kg. It significantly improved the morphology of the non-alcoholic fatty liver.

Conclusion: WZS08 selectively inhibits rat, mouse, and human 11β-hydroxysteroid dehydrogenase 1, and can treat non-alcoholic fatty liver disease in a mouse model.

Decision Tree for the Performance of Intraoperative Liver Biopsy During Bariatric Surgery

BACKGROUND AND AIMS

Bariatric surgery provides a useful opportunity to perform intraoperative liver biopsy to screen for non-alcoholic steatohepatitis (NASH). There is currently no consensus on whether intraoperative liver biopsy should be systematically performed. The aim of this study was to develop and validate a decision tree to guide that choice.

APPROACH AND RESULTS

This prospective study included 102 consecutive patients from the severe obesity outcome network (SOON) cohort in whom liver biopsy was systematically performed during bariatric surgery. A classification and regression tree (CART) was created to identify the nodes that best classified patients with and without NASH. External validation was performed. Seventy-one biopsies were of sufficient quality for analysis (median body mass index 43.3 [40.7; 48.0] kg/m²). NASH was diagnosed in 32.4% of cases. None of the patients with no steatosis on ultrasound had NASH. The only CART node that differentiated between a "high-risk" and a "low-risk" of NASH was alanine aminotransferase (ALT). ALT>53IU/L predicted NASH with a positive predictive value (PPV) of 68% and a negative predictive value (NPP) of 89%, a sensitivity of 77%, and a specificity of 84%. In the external cohort (n=258), PPV was 68%, NPV was 62%, sensitivity was 27%, and specificity was 90%.

CONCLUSIONS

The present work supports intraoperative liver biopsy to screen for NASH in patients with ALT>53IU/L; however, patients with no steatosis on ultrasound should not undergo biopsy. The CART failed to identify an algorithm with a good sensitivity to screen for NASH in patients with ultrasonography-proven steatosis and ALT≤53IU/L.

Research progress in use of traditional Chinese medicine monomer for treatment of non-alcoholic fatty liver disease

With the improvement of people's living standards and the change of eating habits, non-alcoholic fatty liver disease (NAFLD) has gradually become one of the most common chronic liver diseases in the world. However, there are no effective drugs for the treatment of NAFLD. Therefore, it is urgent to find safe, efficient, and economical anti-NAFLD drugs. Compared with western medicines that possess fast lipid-lowering effect, traditional Chinese medicines (TCM) have attracted increasing attention for the treatment of NAFLD due to their unique advantages such as multi-targets and multi-channel mechanisms of action. TCM monomers have been proved to treat NAFLD through regulating various pathways, including inflammation, lipid production, insulin sensitivity, mitochondrial dysfunction, autophagy, and intestinal microbiota. In particular, peroxisome proliferator-activated receptor α (PPAR-α), sterol regulatory element-binding protein 1c (SREBP-1c), nuclear transcription factor kappa (NF-κB), phosphoinositide 3-kinase (PI3K), sirtuin1 (SIRT1), AMP-activated protein kinase (AMPK), p53 and nuclear factor erythroid 2-related factor 2 (Nrf2) are considered as important molecular targets for ameliorating NAFLD by TCM monomers. Therefore, by searching PubMed, Web of Science and SciFinder databases, this paper updates and summarizes the experimental and clinical evidence of TCM monomers for the treatment of NAFLD in the past six years (2015-2020), thus providing thoughts and prospects for further exploring the pathogenesis of NAFLD and TCM monomer therapies.

Role of necroptosis in chronic hepatic inflammation and fibrosis in a mouse model of increased oxidative stress

Mice deficient in the antioxidant enzyme Cu/Zn-superoxide dismutase (Sod1^-/- or Sod1KO mice) have increased oxidative stress, show accelerated aging and develop spontaneous hepatocellular carcinoma (HCC) with age. Similar to humans, HCC development in Sod1KO mice progresses from non-alcoholic fatty liver disease (NAFLD) to non-alcoholic steatohepatitis (NASH) with fibrosis, which eventually progresses to HCC. Oxidative stress plays a role in NAFLD to NASH progression, and liver inflammation is the main mechanism that drives the disease progression from NASH to fibrosis. Because necroptosis is a major source of inflammation, we tested the hypothesis that increased necroptosis in the liver plays a role in increased inflammation and fibrosis in Sod1KO mice. Phosphorylation of MLKL (P-MLKL), a well-accepted marker of necroptosis, and expression of MLKL protein were significantly increased in the livers of Sod1KO mice compared to wild type (WT) mice indicating increased necroptosis. Similarly, phosphorylation of RIPK3 and RIPK3 protein levels were also significantly increased. Markers of pro-inflammatory M1 macrophages, NLRP3 inflammasome, and transcript levels of pro-inflammatory cytokines and chemokines, e.g., TNFα, IL-6, IL-1β, and Ccl2 that are associated with human NASH, were significantly increased. Expression of antioxidant enzymes and heat shock proteins, and markers of fibrosis and oncogenic transcription factor STAT3 were also upregulated and autophagy was downregulated in the livers of Sod1KO mice. Short term treatment of Sod1KO mice with necrostatin-1s (Nec-1s), a necroptosis inhibitor, reversed these conditions. Our data show for the first time that necroptosis-mediated inflammation contributes to fibrosis in a mouse model of increased oxidative stress and accelerated aging, that also exhibits progressive HCC development.

Predicting Non-Alcoholic Fatty Liver Disease Progression and Immune Deregulations by Specific Gene Expression Patterns

Non-alcoholic fatty liver disease (NAFLD) is the most common liver disease worldwide with rising rates in parallel to obesity, type 2 diabetes, and metabolic syndrome. NAFLD includes pathologies ranging from simple steatosis (NAFL) to non-alcoholic steatohepatitis and cirrhosis (NASH), which may eventually develop into hepatocellular carcinoma (HCC). Mechanically, lipids accumulation and insulin resistance act as the first hit, inflammation and fibrosis serve as the second hit. Currently, the diagnosis of NAFLD mainly depends on pathology examination and medical imaging, whereas proper gene signature classifiers are necessary for the evaluation of disease status. Here, we developed three signature classifiers to distinguish different NAFLD disease states (NAFL and NASH). Moreover, we found that B cells, DCs, and MAIT cells are key deregulated immune cells in NAFLD, which are associated with NAFLD and NAFLD-HCC progression. Meanwhile, AKR1B10 and SPP1 are closely related to the above three immune cell infiltrations and immunosuppressive cytokines expressions in NAFLD and NAFLD-HCC. Subsequently, we screened out AKR1B10 and SPP1 sensitive molecules TGX-221, which may provide a possible therapy for NAFLD and NAFLD-HCC.

Current and Potential Therapies Targeting Inflammation in NASH

Nonalcoholic steatohepatitis (NASH) is the advanced form of nonalcoholic fatty liver disease (NAFLD). It is characterized by hepatic steatosis, inflammation, hepatocellular injury, and fibrosis. Inflammation plays a key role in the progression of NASH and can be provoked by intrahepatic (e.g., lipotoxicity, immune responses, oxidative stress and cell death) and extrahepatic sources (adipose tissue or gut). The identification of triggers of inflammation is central to understanding the mechanisms in NASH development and progression and in designing targeted therapies that can halt or reverse the disease. In this review, we summarize the current and potential therapies targeting inflammation in NASH.

miR-34a regulates lipid metabolism by targeting SIRT1 in non-alcoholic fatty liver disease with iron overload

BACKGROUND

Micro-ribonucleic acids (miRNAs) have been implicated in the regulation of non-alcoholic fatty liver disease (NAFLD), a leading cause of chronic liver disease worldwide. The mechanisms by which miR-34a influences NAFLD through the Sirtuin 1 (SIRT1)-related pathway were investigated herein.

METHODS

Male C57BL/6 mice were injected with a miR-34a lentivirus vector inhibitor or control. HepG2 cells were transfected with a miR-34a mimic, inhibitor, SIRT1 small interfering RNA (siRNA), SIRT1 plasmid, and a negative oligonucleotide control to evaluate their role in oleic acid (OA) and excess iron-induced NAFLD. The accumulation of lipids in the mice liver and HepG2 cells was analyzed by triglyceride (TG) detection and hematoxylin and eosin (HE) staining. Additionally, the indexes of oxidative stress related to lipid metabolism were evaluated by western blotting and real-time PCR (qRT-PCR). The levels of intracellular reactive oxygen species (ROS) and mitochondrial membrane potentials were measured by flow cytometry and laser confocal microscopy, respectively. Finally, the dual luciferase reporter assay was conducted to further confirm whether SIRT1 was a direct target of miR-34a.

RESULTS

Overexpression of miR-34a resulted in increased triglyceride accumulation as well as in decreased mitochondrial membrane potential and SIRT1 levels. Silencing of miR-34a increased SIRT1 expression and alleviated triglyceride accumulation in the presence of OA and iron. Additionally, miR-34a directly inhibited SIRT1 by binding to the 3'-untranslated region, as determined via the luciferase reporter assay.

CONCLUSIONS

Our results support the existence of a link between the liver cell mitochondria and miR-34a/SIRT1 signaling. Potential endogenous modulators of NAFLD pathogenesis may ultimately provide new tools for therapeutic intervention.

An Improved qFibrosis Algorithm for Precise Screening and Enrollment into Non-Alcoholic Steatohepatitis (NASH) Clinical Trials

Background: Many clinical trials with potential drug treatment options for non-alcoholic fatty liver disease (NAFLD) are focused on patients with non-alcoholic steatohepatitis (NASH) stages 2 and 3 fibrosis. As the histological features differentiating stage 1 (F1) from stage 2 (F2) NASH fibrosis are subtle, some patients may be wrongly staged by the in-house pathologist and miss the opportunity for enrollment into clinical trials. We hypothesized that our refined artificial intelligence (AI)-based algorithm (qFibrosis) can identify these subtle differences and serve as an assistive tool for in-house pathologists. Methods: Liver tissue from 160 adult patients with biopsy-proven NASH from Singapore General Hospital (SGH) and Peking University People’s Hospital (PKUH) were used. A consensus read by two expert hepatopathologists was organized. The refined qFibrosis algorithm incorporated the creation of a periportal region that allowed for the increased detection of periportal fibrosis. Consequently, an additional 28 periportal parameters were added, and 28 pre-existing perisinusoidal parameters had altered definitions. Results: Twenty-eight parameters (20 periportal and 8 perisinusoidal) were significantly different between the F1 and F2 cases that prompted a change of stage after a careful consensus read. The discriminatory ability of these parameters was further demonstrated in a comparison between the true F1 and true F2 cases as 26 out of the 28 parameters showed significant differences. These 26 parameters constitute a novel sub-algorithm that could accurately stratify F1 and F2 cases. Conclusion: The refined qFibrosis algorithm incorporated 26 novel parameters that showed a good discriminatory ability for NASH fibrosis stage 1 and 2 cases, representing an invaluable assistive tool for in-house pathologists when screening patients for NASH clinical trials.

Clinical spectrum of non-alcoholic fatty liver disease in patients with diabetes mellitus

Background

Non-alcoholic fatty liver disease (NAFLD) is increasingly widespread with an overall global estimated prevalence of 25%. Type 2 diabetes Mellitus (T2DM) is a key contributor to NAFLD progression and predicts moderate-severe liver fibrosis and mortality. However, there is currently no uniform consensus on routine NAFLD screening among T2DM patients, and the risk factors of NAFLD and advanced fibrosis among T2DM patients remain to be clarified fully.

Aim

We explored the prevalence, clinical spectrum, and risk factors of NAFLD and liver fibrosis among T2DM patients.

Methods

This is a cross-sectional study that enrolled subjects from a primary care clinic and a diabetes centre in Singapore. Subjects aged 21 to 70 years of all ethnic groups with an established T2DM diagnosis were included. Subjects with chronic liver diseases of other aetiologies were excluded. All subjects underwent transient elastography for hepatic steatosis and fibrosis assessment. Their demographics, anthropometric measurements and clinical parameters were collected. Statistical analysis was performed using STATA/SE16.0 software.

Results

Among 449 enrolled T2DM subjects, 436 with complete data and valid transient elastography results were analysed. Overall, 78.72% (344/436) of the T2DM subjects had NAFLD, of which 13.08% (45/344) had increased liver stiffness. Higher ALT level (OR = 1.08; 95% CI: 1.03–1.14; p = 0.004), obesity (BMI ≥ 27.5 kg/m2, OR = 2.64; 95% CI: 1.28–5.44; p = 0.008) and metabolic syndrome (OR = 4.36; 95% CI 1.40–13.58; p = 0.011) were independent factors associated with increased CAP (NAFLD). Higher AST level (OR = 1.06; 95% CI: 1.02–1.11; p = 0.008), CAP value (OR = 1.02; 95% CI: 1.00–1.03; p = 0.003), lower platelet count (OR = 0.99; 95% CI: 0.98–1.00; p = 0.009) and concomitant hypertension (OR = 4.56; 95% CI: 1.18–17.62; p = 0.028) were independent factors associated with increased liver stiffness.

Conclusions

Our study demonstrated a considerably high prevalence of NAFLD among T2DM patients, with the proportion of advanced liver fibrosis among T2DM NAFLD patients much higher than the general population. Given that NAFLD is largely asymptomatic, increased awareness and vigilance for identifying NAFLD and increased liver stiffness among T2DM patients should be advocated.

Treatment of nonalcoholic fatty liver disease with dapagliflozin in non-diabetic patients

Steatosis, a condition characterized by excessive lipid deposition. Although usually a benign condition, steatosis mays progress to cirrhosis or hepatocellular carcinoma. Recent evidence suggests that SGLT2 inhibitors suppress the development of nonalcoholic steatohepatitis in humans, as well as in rodent models and that SGLT2 inhibitors alleviate hepatic steatosis or steatohepatitis in obese type 2 diabetic rats or mice. 14 Patients with nonalcoholic fatty liver disease used a fixed dose of 10 mg of dapagliflozin for an average of 75 days. ALT, AST, GGT, insulin, HOMA-IR, and weight levels were significantly lower after treatment. There was no significant correlation between the reduction in HOMA and the reduction in ALT values or weight reduction obtained during treatment and ALT values.

Non-alcoholic Fatty Liver Disease and Alcohol-Related Liver Disease: Two Intertwined Entities

Non-alcoholic fatty liver disease (NAFLD) is the most common cause of chronic liver disease worldwide, with a prevalence of 25-30%. Since its first description in 1980, NAFLD has been conceived as a different entity from alcohol-related fatty liver disease (ALD), despite that, both diseases have an overlap in the pathophysiology, share genetic-epigenetic factors, and frequently coexist. Both entities are characterized by a broad spectrum of histological features ranging from isolated steatosis to steatohepatitis and cirrhosis. Distinction between NAFLD and ALD is based on the amount of consumed alcohol, which has been arbitrarily established. In this context, a proposal of positive criteria for NAFLD diagnosis not considering exclusion of alcohol consumption as a prerequisite criterion for diagnosis had emerged, recognizing the possibility of a dual etiology of fatty liver in some individuals. The impact of moderate alcohol use on the severity of NAFLD is ill-defined. Some studies suggest protective effects in moderate doses, but current evidence shows that there is no safe threshold for alcohol consumption for NAFLD. In fact, given the synergistic effect between alcohol consumption, obesity, and metabolic dysfunction, it is likely that alcohol use serves as a significant risk factor for the progression of liver disease in NAFLD and metabolic syndrome. This also affects the incidence of hepatocellular carcinoma. In this review, we summarize the overlapping pathophysiology of NAFLD and ALD, the current data on alcohol consumption in patients with NAFLD, and the effects of metabolic dysfunction and overweight in ALD.

Association of Genetic and Environmental Factors with Non-Alcoholic Fatty Liver Disease in a Chinese Han Population

Lifestyle choices such as the intake of sweets, history of diseases, and genetic variants seem to play a role in the pathogenesis of non-alcoholic fatty liver disease (NAFLD). To explore which genetic and environmental factors are associated with NAFLD in a Chinese Han population, we conducted this study. We collected the medical reports, lifestyle details, and blood samples of individuals and used the polymerase chain reaction-ligase detection reaction method to genotype the single-nucleotide polymorphism (SNPs) from the 2113 eligible people. The GG genotype of the additive model of rs7493 in the PON2, the CC genotype of the additive and recessive models of rs7593130 in the ADCY3, together with dyslipidemia, regular intake of egg and sweets and hypertension, increased the risk of NAFLD (adjusted OR > 1, p < 0.05). The TT genotype of the additive and dominant models of rs11583680 in the PCSK9, together with the regular intake of vegetable, reduced the risk of NAFLD (adjusted OR < 1, p < 0.05). In addition, interactions between some variables were found. Eventually, we identified three SNPs and six environmental factors associated with NAFLD. These results provide the theoretical basis for gene and other risk factors screening to prevent NAFLD.

Extraction and structural analysis of Angelica sinensis polysaccharide with low molecular weight and its lipid-lowering effect on nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) is one of the prevalent and typical chronic liver diseases. In this study, we extracted a novel Angelica sinensis polysaccharide (ASP) with low molecular weight (MW) of 3.2 kDa through optimized "one-step" purification process. The major monosaccharide components of ASP were mannose, rhamnose, glucuronic acid, galactose, arabinose, and xylose with weight ratio of 0.23:0.17:14.41:0.39:1.68:0.87, respectively. Herein, "small" ASP could serve as an effective therapeutic option for NAFLD both in free fatty acid-induced L02 models and in high-fat diet-induced mice models. Results revealed that low MW ASP dose-dependently decreased TG, TC in vitro and TG, TC, ALT, HDL-C, and LDL-C in vivo. Oil Red O-positive area and Nile red fluorescence intensity decreased in ASP treatment groups both in vitro and in vivo which suggested ASP could reduce lipid accumulation and fatty regeneration. Hematoxylin-eosin staining results shown a decrease in hepatocytes ballooning indicating that ASP could ameliorate liver lipid degeneration. Briefly, a novel polysaccharide with low MW was successfully obtained which can prospectively act as NAFLD therapy.

Zinc Supplementation Alleviates Lipid and Glucose Metabolic Disorders Induced by a High-Fat Diet

Zinc deficiency is a risk factor for the development of obesity and diabetes. Studies have shown lower serum zinc levels in obese individuals and those with diabetes. We speculate that zinc supplementation can alleviate obesity and diabetes and, to some extent, their complications. To test our hypothesis, we investigated the effects of zinc supplementation on mice with high-fat diet (HFD)-induced hepatic steatosis in vivo and in vitro by adding zinc to the diet of mice and the medium of HepG2 cells. Both results showed that high levels of zinc could alleviate the glucose and lipid metabolic disorders induced by a HFD. High zinc can reduce glucose production, promote glucose absorption, reduce lipid deposition, improve HFD-induced liver injury, and regulate energy metabolism. This study provides novel insight into the treatment of non-alcoholic fatty liver disease and glucose metabolic disorder.

Analysis of piRNA expression spectra in a non-alcoholic fatty liver disease mouse model induced by a methionine- and choline-deficient diet

Non-alcoholic fatty liver disease (NAFLD) has become a common health issue worldwide, and P-element-induced wimpy testis (PIWI)-interacting RNAs (piRNAs) have been shown to be differentially expressed in a variety of diseases. The aim of the present study was to investigate the potential relationship between piRNA and NAFLD. A NAFLD mouse model was established using a methionine- and choline-deficient (MCD) diet and methionine- and choline-sufficient (MCS) diet. Following this, mouse liver tissues were removed and stained with hematoxylin and eosin, and the levels of alanine aminotransferase, aspartate aminotransferase, total cholesterol and triglyceride were measured. Moreover, the liver tissues of the control and model groups were selected for piRNA gene chip analysis to identify piRNAs with differential expression in NAFLD. In addition, the differentially expressed piRNAs screened from the microarray were assessed by reverse transcription-quantitative PCR (RT-qPCR). piRNAs with potential research value were also selected for further analysis of target genes, using Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathways. The present study identified a total of 1,285 piRNAs with differential expression levels. The results indicated that in the model group, 641 piRNAs were upregulated, while 644 piRNAs were downregulated. Furthermore, piRNAs were enriched in ‘cancer’, ‘Hippo signaling’, ‘Wnt signaling’ and ‘Mitogen-activated protein kinase signaling’ pathways. The RT-qPCR results demonstrated that piRNA DQ566704 and piRNA DQ723301 were significantly upregulated in the model group, which was largely consistent with the analysis results of the piRNA arrays. Therefore, the results of the piRNA arrays and the further analyses in the present study were considered reliable. Collectively, the present results suggest that differentially expressed piRNAs exist in NAFLD and may affect the development of NAFLD via related pathways.

β-Klotho gene variation is associated with liver damage in children with NAFLD

BACKGROUND & AIM

Non-alcoholic fatty liver disease (NAFLD) is the leading cause of chronic liver disease in adults and children. Along with obesity, diabetes and insulin resistance, genetic factors strongly impact on NAFLD development and progression. Dysregulated bile acid metabolism and the fibroblast growth factor 19 (FGF19) pathway play a pivotal role in NAFLD pathogenesis. However, the mechanism through which the FGF19 receptor system is associated with liver damage in NAFLD remains to be defined.

METHODS

We evaluated the impact of the rs17618244 G>A β-Klotho (KLB) variant on liver damage in 249 pediatric patients with biopsy-proven NAFLD and the association of this variant with the expression of hepatic and soluble KLB. In vitro models were established to investigate the role of the KLB mutant.

RESULTS

The KLB rs17618244 variant was associated with an increased risk of ballooning and lobular inflammation. KLB plasma levels were lower in carriers of the rs17618244 minor A allele and were associated with lobular inflammation, ballooning and fibrosis. In HepG2 and Huh7 hepatoma cell lines, exposure to free fatty acids caused a severe reduction of intracellular and secreted KLB. Finally, KLB downregulation obtained by the expression of a KLB mutant in HepG2 and Huh7 cells induced intracellular lipid accumulation and upregulation of p62, ACOX1, ACSL1, IL-1β and TNF-α gene expression.

CONCLUSION

In conclusion, we showed an association between the rs17618244 KLB variant, which leads to reduced KLB expression, and the severity of NAFLD in pediatric patients. We can speculate that the KLB protein may exert a protective role against lipotoxicity and inflammation in hepatocytes.

LAY SUMMARY

Genetic and environmental factors strongly impact on the pathogenesis and progression of non-alcoholic fatty liver disease (NAFLD). The FGF19/FGFR4/KLB pathway plays a pivotal role in the pathogenesis of NAFLD. The aim of the study was to investigate the impact of a genetic variant in the KLB gene on the severity of liver disease. Our data suggest that the KLB protein plays a protective role against lipotoxicity and inflammation in hepatocytes.

Selenium and selenoprotein P in nonalcoholic fatty liver disease

Conflicting data link nonalcoholic fatty liver disease (NAFLD), a disease with no currently approved treatment, with selenium (Se) and selenoprotein P (SELENOP), a glycoprotein synthesized and primarily secreted by the hepatocytes, functioning as a Se transporter from the liver to other tissues. This review aims to summarize the evidence between Se, SELENOP, and NAFLD, which may hopefully clarify whether current data on Se and SELENOP in NAFLD warrant further investigation for their diagnostic and therapeutic potential. Most, albeit not all, experimental data show a favorable effect of Se on hepatic steatosis, inflammation, and fibrosis. It seems that Se may exert an antioxidant effect on the liver, at least partly via increasing the activity of glutathione peroxidase, whose depletion contributes to the pathogenesis of hepatic inflammation and fibrosis. Se may also affect metalloproteinases, cytokines, and growth factors participating in the pathogenesis of NAFLD and, most importantly, may induce the apoptosis of hepatic stellate cells, the key players in hepatic fibrosis. However, the association between Se or SELENOP and insulin resistance, which is a principal pathogenetic factor of NAFLD, remains inconclusive. Clinical studies on Se or SELENOP in NAFLD are conflicting, apart from those in advanced liver disease (cirrhosis or hepatocellular carcinoma), in which lower circulating Se and SELENOP are constant findings. Existing data warrant further mechanistic studies in valid animal models of human NAFLD. Prospective cohort studies and possibly randomized controlled trials are also needed to elucidate the diagnostic and therapeutic potential of Se supplementation in selected NAFLD individuals with Se deficiency.