Epidemiology of non-alcoholic fatty liver disease and risk of hepatocellular carcinoma progression

Wnt/β-Catenin signaling pathway in hepatocellular carcinoma: pathogenic role and therapeutic target

Hepatocellular carcinoma (HCC) is the most common primary malignant liver tumor and one of the leading causes of cancer-related deaths worldwide. The Wnt/β-Catenin signaling pathway is a highly conserved pathway involved in several biological processes, including the improper regulation that leads to the tumorigenesis and progression of cancer. New studies have found that abnormal activation of the Wnt/β-Catenin signaling pathway is a major cause of HCC tumorigenesis, progression, and resistance to therapy. New perspectives and approaches to treating HCC will arise from understanding this pathway. This article offers a thorough analysis of the Wnt/β-Catenin signaling pathway's function and its therapeutic implications in HCC.

Anti-osteoporotic treatments in the era of non-alcoholic fatty liver disease: friend or foe

Over the last years non-alcoholic fatty liver disease (NAFLD) has grown into the most common chronic liver disease globally, affecting 17-38% of the general population and 50-75% of patients with obesity and/or type 2 diabetes mellitus (T2DM). NAFLD encompasses a spectrum of chronic liver diseases, ranging from simple steatosis (non-alcoholic fatty liver, NAFL) and non-alcoholic steatohepatitis (NASH; or metabolic dysfunction-associated steatohepatitis, MASH) to fibrosis and cirrhosis with liver failure or/and hepatocellular carcinoma. Due to its increasing prevalence and associated morbidity and mortality, the disease-related and broader socioeconomic burden of NAFLD is substantial. Of note, currently there is no globally approved pharmacotherapy for NAFLD. Similar to NAFLD, osteoporosis constitutes also a silent disease, until an osteoporotic fracture occurs, which poses a markedly significant disease and socioeconomic burden. Increasing emerging data have recently highlighted links between NAFLD and osteoporosis, linking the pathogenesis of NAFLD with the process of bone remodeling. However, clinical studies are still limited demonstrating this associative relationship, while more evidence is needed towards discovering potential causative links. Since these two chronic diseases frequently co-exist, there are data suggesting that anti-osteoporosis treatments may affect NAFLD progression by impacting on its pathogenetic mechanisms. In the present review, we present on overview of the current understanding of the liver-bone cross talk and summarize the experimental and clinical evidence correlating NAFLD and osteoporosis, focusing on the possible effects of anti-osteoporotic drugs on NAFLD.

The Novel GlycoPEGylated FGF21 Analog Pegozafermin Activates Human FGF Receptors and Improves Metabolic and Liver Outcomes in Diabetic Monkeys and Healthy Human Volunteers

Pegozafermin (also known as BIO89-100) is a glycoPEGylated analog of fibroblast growth factor 21 (FGF21) under development to treat nonalcoholic steatohepatitis (NASH) and severe hypertriglyceridemia (SHTG). In cell-based assays, pegozafermin had a similar receptor engagement profile as recombinant FGF21, with approximately eightfold higher potency at fibroblast growth factor receptor 1c (FGFR1c). In diabetic monkeys, once-weekly and once-every-2-weeks regimens of subcutaneous pegozafermin provided rapid and robust benefits for an array of metabolic biomarkers, including triglycerides, cholesterol, fasting glucose, glycated hemoglobin, adiponectin, alanine aminotransferase, food intake, and body weight. In a single ascending dose study in healthy volunteers, subcutaneously administered pegozafermin was associated with statistically significant improvements in triglycerides, low- and high-density lipoprotein-cholesterol, and adiponectin, an insulin-sensitizing and anti-inflammatory adipokine. Pharmacokinetic half-lives ranged from 55 to 100 hours over the clinically relevant dose range, consistent with the expected half-life extension by glycoPEGylation. These findings provide evidence that pegozafermin is a promising candidate molecule for the treatment of patients with NASH or SHTG. SIGNIFICANCE STATEMENT: Fibroblast growth factor 21 (FGF21) is a stress-inducible hormone that has important roles in regulating energy balance and glucose and lipid homeostasis. Studies presented here demonstrate that a novel long-acting FGF21 analog, pegozafermin, has similar pharmacologic properties as FGF21 and that repeated, subcutaneous dosing of pegozafermin in diabetic monkeys and healthy humans improves lipid metabolism, glucose metabolism, weight, and liver transaminases. These results support future development of pegozafermin for the treatment of metabolic diseases, including nonalcoholic steatohepatitis and severe hypertriglyceridemia.

USP25 promotes hepatocellular carcinoma progression by interacting with TRIM21 via the Wnt/β-catenin signaling pathway

BACKGROUND

Hepatocellular carcinoma (HCC) is one of the most common malignant tumors in the world. The ubiquitin-specific peptidase 25 (USP25) protein has been reported to participate in the development of several cancers. However, few studies have reported its association with HCC. In this study, we aimed to investigate the function and mechanism of USP25 in the progression of HCC.

METHODS

We analyzed USP25 protein expression in HCC based on The Cancer Genome Atlas (TCGA) and International Cancer Genome Consortium (ICGC) database cohorts. Then, we constructed USP25-overexpressing and USP25-knockdown HepG2, MHCC97H, and L-O2 cells. We detected the biological function of USP25 by performing a series of assays, such as Cell Counting Kit-8 (CCK-8), colony formation, transwell, and wound healing assays. Western blotting and quantitative real-time polymerase chain reaction (qRT-PCR) analyses were performed to detect the interaction between USP25 and the Wnt/β-catenin signaling pathway. The relationship between USP25 and tripartite motif-containing 21 (TRIM21) was assessed through mass spectrometry and co-immunoprecipitation (Co-IP) analysis. Finally, we constructed a mouse liver cancer model with the USP25 gene deletion to verify in vivo role of USP25.

RESULTS

USP25 was highly expressed in HCC tissue and HCC cell lines. Importantly, high expression of USP25 in tissues was closely related to a poor prognosis. USP25 knockdown markedly reduced the proliferation, migration, and invasion of HepG2 and MHCC97H cells, whereas USP25 overexpression led to the opposite effects. In addition, we demonstrated that USP25 interacts with TRIM21 to regulate the expression of proteins related to epithelial-mesenchymal transition (EMT; E-cadherin, N-cadherin, and Snail) and the Wnt/β-catenin pathway (β-catenin, Adenomatous polyposis coli, Axin2 and Glycogen synthase kinase 3 beta) and those of their downstream proteins (C-myc and Cyclin D1). Finally, we verified that knocking out USP25 inhibited tumor growth and distant metastasis in vivo .

CONCLUSIONS

In summary, our data showed that USP25 was overexpressed in HCC. USP25 promoted the proliferation, migration, invasion, and EMT of HCC cells by interacting with TRIM21 to activate the β-catenin signaling pathway.

Apigenin attenuates atherosclerosis and non-alcoholic fatty liver disease through inhibition of NLRP3 inflammasome in mice

Apigenin (APN), a flavone found in several plant foods with various biological properties such as anti-obesity, anti-inflammation and other abilities, alleviates atherosclerosis and non-alcoholic fatty liver disease (NAFLD) induced by a high fat diet (HFD) in mice. However, the underlying mechanisms have not been fully understood. In this study, we investigated the role of NLRP3 in anti-atherosclerosis and anti-NAFLD effect of APN in mouse models with NLRP3 deficiency. Atherosclerosis and NAFLD models were established by treatment of low density lipoprotein receptor-deficient (Ldlr^-/-) mice and NLRP3^-/- Ldlr^-/- mice with a HFD diet (20% fat and 0.5% cholesterol) with or without APN. En face lipid accumulation analysis, plasma lipid levels, hepatic lipid accumulation and inflammation were analyzed and quantified. For in vitro experiments, HepG2 cells were stimulated by LPS plus oleic acid (OA) in the absence or presence of APN (50 μM). Lipid accumulation and the effect of APN on the NLRP3/NF-κB signaling pathway were investigated. APN administration partly reversed atherosclerosis and hepatic lipid accumulation, and decreased body weight and plasma lipid levels in Ldlr^-/- mice when fed a HFD. Compared with Ldlr^-/- mice, NLRP3^-/- Ldlr^-/- mice showed more severe atherosclerosis and hepatic lipid accumulation. Treating the HepG2 cells with APN reduced lipid accumulation. APN also inhibited activation of the NLRP3/ NF-κB signaling pathway stimulated by OA together with LPS. Our results indicate that APN supplementation prevents atherosclerosis and NAFLD via NLRP3 inhibition in mice, and suggest that APN might be a potential therapeutic agent for the prevention of atherosclerosis and NAFLD.

High Prevalence of Severe Hepatic Fibrosis in Type 2 Diabetic Outpatients Screened for Non-Alcoholic Fatty Liver Disease

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) is a highly frequent condition in patients with type 2 diabetes (T2D), but the identification of subjects at higher risk of developing the more severe forms remains elusive in clinical practice. The aim of this study was to evaluate the occurrence and severity of liver fibrosis and its predictive factors in T2D outpatients without a known history of chronic liver disease by using recommended non-invasive methods.

METHODS

Consecutive T2D outpatients underwent a set of measurements of clinical and laboratory parameters, FIB-4 score (Fibrosis-4 index), and liver stiffness with controlled attenuation-parameter (CAP) performed by transient elastography (FibroScan) after excluding previous causes of liver disease.

RESULTS

Among the 205 T2D outpatients enrolled in the study (median age: 64 years, diabetes duration: 11 years, HbA1c: 7.4%, and BMI: 29.6 kg/m²), 54% had high ALT and/or AST levels, 15.6% had liver stiffness value > 10.1 kPa (severe fibrosis), 55.1% had CAP values > 290 dB/m (severe steatosis), and FIB-4 score was >2 in 11.2% of subjects (>2.67 in 15 subjects). Moreover, 49 (23.9%) T2D patients had clinically meaningful liver harm, with either a FIB-4 score > 2 and/or FibroScan > 10.1 kPa. At regression analysis, BMI, HbA1c, creatinine, and triglycerides values were independent predictors of liver fibrosis.

CONCLUSIONS

Liver fibrosis is a frequent finding in T2D outpatients without a known history of liver disease, especially in those with obesity, hypertriglyceridemia, worse glycemic control, and high creatinine levels.

Effect of Isoquercitrin on Free Fatty Acid-Induced Lipid Accumulation in HepG2 Cells

Liver metabolic disorders and oxidative stress are crucial factors in the development of nonalcoholic fatty liver disease (NAFLD); however, treatment strategies to combat NAFLD remain poorly established, presenting an important challenge that needs to be addressed. Herein, we aimed to examine the effect of isoquercitrin on lipid accumulation induced by exogenous free fatty acids (FFA) using HepG2 cells and elucidate the underlying molecular mechanism. The cells were exposed to 0.5 mM FFA to induce intracellular lipid accumulation, followed by co-treatment with isoquercitrin to confirm the potential inhibitory effect on FFA-induced lipid production. HepG2 cells exposed to FFA alone exhibited intracellular lipid accumulation, compromised endoplasmic reticulum (ER) stress, and enhanced expression of proteins and genes involved in lipid synthesis; however, co-treatment with isoquercitrin decreased the expression of these molecules in a dose-dependent manner. Furthermore, isoquercitrin could activate AMP-activated protein kinase (AMPK), a key regulatory protein of hepatic fatty acid oxidation, suppressing new lipid production by phosphorylating acetyl-CoA carboxylase (ACC) and inhibiting sterol regulatory element-binding transcription factor 1 (SREBP-1)/fatty acid synthase (FAS) signals. Overall, these findings suggest that isoquercitrin can be employed as a therapeutic agent to improve NAFLD via the regulation of lipid metabolism by targeting the AMPK/ACC and SREBP1/FAS pathways.

Global Epidemiology and Genetics of Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is one of the leading cancers worldwide. Classically, HCC develops in genetically susceptible individuals who are exposed to risk factors, especially in the presence of liver cirrhosis. Significant temporal and geographic variations exist for HCC and its etiologies. Over time, the burden of HCC has shifted from the low-moderate to the high sociodemographic index regions, reflecting the transition from viral to nonviral causes. Geographically, the hepatitis viruses predominate as the causes of HCC in Asia and Africa. Although there are genetic conditions that confer increased risk for HCC, these diagnoses are rarely recognized outside North America and Europe. In this review, we will evaluate the epidemiologic trends and risk factors of HCC, and discuss the genetics of HCC, including monogenic diseases, single-nucleotide polymorphisms, gut microbiome, and somatic mutations.

Role of non-invasive methods in detecting liver impairment in familial Mediterranean fever adult patients with persistent hepatic cytolysis

Familial Mediterranean fever (FMF) patients may have hepatic cytolysis, although its origin is not formally elucidated. We aimed to evaluate liver involvement in familial Mediterranean fever (FMF) using non-invasive methods. All adult FMF patients harboring two non-ambiguous mutations of the MEFV gene with hepatic cytolysis were identified in a French tertiary adult center for FMF. Liver impairment was explored with FibroMax (a non-invasive method to estimate hepatic steatosis, necrosis, inflammation and fibrosis) and liver ultrasound. Among 520 FMF adult patients, 43 had persistent hepatic cytolysis and 20 patients were included (11 women, median age at inclusion: 49.5 years). According to the FibroMax results, patients were classified as having steatosis, fibrosis, and possible or definite nonalcoholic steato-hepatitis in 10 (50%), 9 (45%) and 7 (35%) of cases, respectively. The score of steatosis did not seem associated with the usual metabolic risk factors. No significant association was found between the cumulated dose of colchicine and any of the scores included in FibroMax. In adult FMF patients with persistent hepatic cytolysis, steatosis is the first cause to consider even in the absence of usual metabolic risk factors, suggesting other mechanisms. Colchicine did not seem to be involved in this toxicity.

Risk factors and diagnostic biomarkers for nonalcoholic fatty liver disease-associated hepatocellular carcinoma: Current evidence and future perspectives

High rates of excessive calorie intake diets and sedentary lifestyles have led to a global increase in nonalcoholic fatty liver disease (NAFLD). As a result, this condition has recently become one of the leading causes of hepatocellular carcinoma (HCC). Furthermore, the incidence of NAFLD-associated HCC (NAFLD-HCC) is expected to increase in the near future. Advanced liver fibrosis is the most common risk factor for NAFLD-HCC. However, up to 50% of NAFLD-HCC cases develop without underlying liver cirrhosis. Epidemiological studies have revealed many other risk factors for this condition; including diabetes, other metabolic traits, obesity, old age, male sex, Hispanic ethnicity, mild alcohol intake, and elevated liver enzymes. Specific gene variants, such as single-nucleotide polymorphisms of patatin-like phospholipase domain 3, transmembrane 6 superfamily member 2, and membrane-bound O-acyl-transferase domain-containing 7, are also associated with an increased risk of HCC in patients with NAFLD. This clinical and genetic information should be interpreted together for accurate risk prediction. Alpha-fetoprotein (AFP) is the only biomarker currently recommended for HCC screening. However, it is not sufficiently sensitive in addressing this diagnostic challenge. The GALAD score can be calculated based on sex, age, lectin-bound AFP, AFP, and des-carboxyprothrombin and is reported to show better diagnostic performance for HCC. In addition, emerging studies on genetic and epigenetic biomarkers have also yielded promising diagnostic potential. However, further research is needed to establish an effective surveillance program for the early diagnosis of NAFLD-HCC.

Acetyl-CoA metabolism drives epigenome change and contributes to carcinogenesis risk in fatty liver disease

BACKGROUND

The incidence of non-alcoholic fatty liver disease (NAFLD)-associated hepatocellular carcinoma (HCC) is increasing worldwide, but the steps in precancerous hepatocytes which lead to HCC driver mutations are not well understood. Here we provide evidence that metabolically driven histone hyperacetylation in steatotic hepatocytes can increase DNA damage to initiate carcinogenesis.

METHODS

Global epigenetic state was assessed in liver samples from high-fat diet or high-fructose diet rodent models, as well as in cultured immortalized human hepatocytes (IHH cells). The mechanisms linking steatosis, histone acetylation and DNA damage were investigated by computational metabolic modelling as well as through manipulation of IHH cells with metabolic and epigenetic inhibitors. Chromatin immunoprecipitation and next-generation sequencing (ChIP-seq) and transcriptome (RNA-seq) analyses were performed on IHH cells. Mutation locations and patterns were compared between the IHH cell model and genome sequence data from preneoplastic fatty liver samples from patients with alcohol-related liver disease and NAFLD.

RESULTS

Genome-wide histone acetylation was increased in steatotic livers of rodents fed high-fructose or high-fat diet. In vitro, steatosis relaxed chromatin and increased DNA damage marker γH2AX, which was reversed by inhibiting acetyl-CoA production. Steatosis-associated acetylation and γH2AX were enriched at gene clusters in telomere-proximal regions which contained HCC tumour suppressors in hepatocytes and human fatty livers. Regions of metabolically driven epigenetic change also had increased levels of DNA mutation in non-cancerous tissue from NAFLD and alcohol-related liver disease patients. Finally, genome-scale network modelling indicated that redox balance could be a key contributor to this mechanism.

CONCLUSIONS

Abnormal histone hyperacetylation facilitates DNA damage in steatotic hepatocytes and is a potential initiating event in hepatocellular carcinogenesis.

The advantages of physical exercise as a preventive strategy against NAFLD in postmenopausal women

BACKGROUND

The prevalence and severity of nonalcoholic fatty liver disease (NAFLD) increase in women after menopause. This narrative review discusses the causes and consequences of NAFLD in postmenopausal women and describes how physical activity can contribute to its prevention.

METHODS

The authors followed the narrative review method to perform a critical and objective analysis of the current knowledge on the topic. The Medical Subject Heading keywords 'physical exercise', 'menopause', 'hormone replacement therapy', 'estradiol' and 'NAFLD' were used to establish a conceptual framework. The databases used to collect relevant references included Medline and specialized high-impact journals.

RESULTS

Higher visceral adiposity, higher rate of lipolysis in adipose tissue after oestrogen drop and changes in the expression of housekeeping proteins involved in hepatic lipid management are observed in women after menopause, contributing to NAFLD. Excessive liver steatosis leads to hepatic insulin resistance, oxidative stress and inflammation, accelerating NAFLD progression. Physical activity brings beneficial effects against several postmenopausal-associated complications, including NAFLD progression. Aerobic and resistance exercises partially counteract alterations induced by metabolic syndrome in sedentary postmenopausal women, impacting NAFLD progression and severity.

CONCLUSIONS

With the increased global obesity epidemic in developing countries, NAFLD is becoming a severe problem with increased prevalence in women after menopause. Evidence shows that physical activity may delay NAFLD development and severity in postmenopausal women, although the prescription of age-appropriate physical activity programmes is advisable to assure the health benefits.

Cholesterol Metabolism: A Double-Edged Sword in Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) represents a leading cause of cancer-related deaths globally. The rising incidence of metabolic syndrome and its hepatic manifestation, nonalcoholic fatty liver disease (NAFLD), have emerged as the fastest-growing cause of HCC in recent years. Cholesterol, a major lipid component of the cell membrane and lipoprotein particles, is primarily produced and metabolized by the liver. Numerous studies have revealed an increased cholesterol biosynthesis and uptake, reduced cholesterol exportation and excretion in HCC, which all contribute to lipotoxicity, inflammation, and fibrosis, known HCC risk factors. In contrast, some clinical studies have shown that higher cholesterol is associated with a reduced risk of HCC. These contradictory observations imply that the relationship between cholesterol and HCC is far more complex than initially anticipated. Understanding the role of cholesterol and deciphering the underlying molecular events in HCC development is highly relevant to developing new therapies. Here, we discuss the current understanding of cholesterol metabolism in the pathogenesis of NAFLD-associated HCC, and the underlying mechanisms, including the roles of cholesterol in the disruption of normal function of specific cell types and signaling transduction. We also review the clinical progression in evaluating the association of cholesterol with HCC. The therapeutic effects of lowering cholesterol will also be summarized. We also interpret reasons for the contradictory observations from different preclinical and human studies of the roles of cholesterol in HCC, aiming to provide a critical assessment of the potential of cholesterol as a therapeutic target.

Hepatocellular carcinoma in the non-cirrhotic liver

Liver cirrhosis is an established high-risk factor for HCC and the majority of patients diagnosed with HCC have cirrhosis. However, HCC also arises in non-cirrhotic livers in approximately 20 %of all cases. HCC in non-cirrhotic patients is often clinically silent and surveillance is usually not recommended. HCC is often diagnosed at an advanced stage in these patients. Current information about HCC in patients with non-cirrhotic liver is limited. Here we review the current knowledge on epidemiology, clinical features and imaging features of those patiens.

The association between urinary bisphenol A levels and nonalcoholic fatty liver disease in Korean adults: Korean National Environmental Health Survey (KoNEHS) 2015-2017

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) is becoming a global health problem. Bisphenol A (BPA), one of most widely used environmental chemicals, is suspected to be a contributor to the development NAFLD. This study was performed to examine the relationship between human BPA levels and risk of NAFLD.

METHODS

The data (n = 3476 adults: 1474 men and 2002 women) used in this study were obtained from the Korean National Environmental Health Survey III (2015-2017). BPA levels were measured in urine samples. NAFLD was defined using hepatic steatosis index after exclusion of other causes of hepatic diseases.

RESULTS

There was a significant linear relationship between the elevated urinary BPA concentrations and risk of NAFLD. In a univariate analysis, odds ratio (OR) of the highest quartile of urinary BPA level was 1.47 [95% confidence interval (CI) 1.11-1.94] compared to the lowest quartile. After adjusted with covariates, the ORs for NAFLD in the third and fourth quartiles were 1.31 [95% CI 1.03-1.67] and 1.32 [95% CI 1.03-1.70], respectively.

CONCLUSIONS

Urinary BPA levels are positively associated with the risk of NAFLD in adults. Further experimental studies are needed to understand the molecular mechanisms of BPA on NAFLD prevalence.

Endoplasmic Reticulum Stress and Autophagy in the Pathogenesis of Non-alcoholic Fatty Liver Disease (NAFLD): Current Evidence and Perspectives

PURPOSE OF REVIEW

Non-alcoholic fatty liver disease (NAFLD) is one of the most common causes of chronic liver disease with rising prevalence worldwide. Herein, we provide a comprehensive overview of the current knowledge supporting the role of ER stress and autophagy processes in NAFLD pathogenesis and progression. We also highlight the interrelation between these two pathways and the impact of ER stress and autophagy modulators on NAFLD treatment.

RECENT FINDINGS

The pathophysiological mechanisms involved in NAFLD progression are currently under investigation. The endoplasmic reticulum (ER) stress and the concomitant unfolded protein response (UPR) seem to contribute to its pathogenesis mainly due to high ER content in the liver which exerts significant metabolic functions and can be dysregulated. Furthermore, disruption of autophagy processes has also been identified in NAFLD. The crucial role of these two pathways in NAFLD is underlined by the fact that they have recently emerged as promising targets of therapeutic interventions. There is a greater need for finding the natural/chemical compounds and drugs which can modulate the ER stress pathway and autophagy for the treatment of NAFLD. Clarifying the inter-relation between these two pathways and their interaction with inflammatory and apoptotic mechanisms will allow the development of additional therapeutic options which can better target and reprogram the underlying pathophysiological pathways, aiming to attenuate NAFLD progression.