Global burden of NAFLD and NASH: trends, predictions, risk factors and prevention

Suppressing NLRP2 expression accelerates hepatic steatosis: A mechanism involving inflammation and oxidative stress

Nonalcoholic fatty liver disease (NAFLD) is characterized by lipid accumulation and inflammation in the liver, contributing to a broad spectrum of severe pathologies, such as metabolic syndrome and hepatocellular carcinoma. Presently, the pathogenesis that attributes to NAFLD has not been fully understood. NLRP2 has been shown to inhibit the NF-κB signaling, and thus may contribute to regulate the inflammatory response. However, its role in NAFLD is largely unclear. In the study, we found that NLRP2 was markedly decreased in liver tissues of individuals with severe steatosis, or in a genetic deficiency (ob/ob) mice. High fat diet (HFD) feeding also led to a significant reduction of NLRP2 in liver of mice. Then, the wild type (WT) and NLRP2 knockout (KO) mice were used to further explore the role of NLRP2 in the NAFLD progression. NLRP2 knockout mice exhibited severer metabolic syndrome and hepatic steatosis after HFD administration, as evidenced by the increased body weight, liver histological changes and lipid accumulation. Moreover, HFD feeding-induced inflammation was significantly accelerated by the loss of NLRP2, as evidenced by the increased expression of pro-inflammatory cytokines and activation of nuclear factor κB (NF-κB) pathway. In addition, oxidative stress triggered by HFD was further promoted by NLRP2 deletion through repressing NF-E2-related factor 2 (Nrf2) pathway. In vitro, we surprisingly found that promoting Nrf2 activation could attenuate NLRP2 knockout-accelerated inflammation and reactive oxygen species (ROS) generation. Therefore, our study indicated that NLRP2 might be a potential target for developing effective therapeutic strategy to prevent NAFLD progression.

Serotonin signals through a gut-liver axis to regulate hepatic steatosis

Nonalcoholic fatty liver disease (NAFLD) is increasing in worldwide prevalence, closely tracking the obesity epidemic, but specific pharmaceutical treatments for NAFLD are lacking. Defining the key molecular pathways underlying the pathogenesis of NAFLD is essential for developing new drugs. Here we demonstrate that inhibition of gut-derived serotonin synthesis ameliorates hepatic steatosis through a reduction in liver serotonin receptor 2A (HTR2A) signaling. Local serotonin concentrations in the portal blood, which can directly travel to and affect the liver, are selectively increased by high-fat diet (HFD) feeding in mice. Both gut-specific Tph1 knockout mice and liver-specific Htr2a knockout mice are resistant to HFD-induced hepatic steatosis, without affecting systemic energy homeostasis. Moreover, selective HTR2A antagonist treatment prevents HFD-induced hepatic steatosis. Thus, the gut TPH1-liver HTR2A axis shows promise as a drug target to ameliorate NAFLD with minimal systemic metabolic effects.

No effective pharmacological treatments exist for nonalcoholic fatty liver disease (NAFLD). Here, the authors show that serotonin concentration in the portal blood is increased in nine human subjects and in mice fed a high-fat diet, and that local serotonin signaling ablation, either genetically or with an antagonist, prevents hepatic steatosis in mice.

Enhanced hepatic glycogen synthesis and suppressed adenosine deaminase activity by lithium attenuates hepatic triglyceride accumulation in nicotine-exposed rats

Reduced liver glycogen synthesis might signify increased glucose flux towards fat synthesis and triggers hepatic triglyceride accumulation and dysmetabolism. Adenosine deaminase (ADA) reduces adenosine content which increases glycogenolysis. In the present study, we evaluate the effect of modulating glycogen synthesis and ADA by lithium chloride (LiCl) on nicotine-induced dysmetabolism. Twenty four male Wistar rats (n = 6/group) were allotted into four groups namely; vehicle-treated (po), nicotine-treated (1.0 mg/kg; po), LiCl-treated (5.0 mg/kg; po) and nicotine + LiCl-treated groups. The treatments lasted for 8 weeks. Nicotine exposure resulted in reduced body weight gain, liver weight, visceral adiposity, glycogen content and synthase. Along with increased insulin resistance (IR), fasting plasma glucose, lactate, plasma and hepatic ADA, XO, UA, and triglyceride (TG), total cholesterol (TC), free fatty acid, lipid peroxidation and liver injury markers. However, plasma and hepatic glucose-6-phosphate dehydrogenase-dependent antioxidant defenses were not affected by nicotine exposure. Concurrent treatment with LiCl normalizes all alterations with exception of hepatic TC. This result shows that enhancement of hepatic glycogen synthesis and suppression of ADA/XO/uric acid pathway by lithium can salvage the liver from nicotine-induced TG accumulation.

Global, regional, and national age-sex-specific mortality for 282 causes of death in 195 countries and territories, 1980-2017: a systematic analysis for the Global Burden of Disease Study 2017

BACKGROUND

Global development goals increasingly rely on country-specific estimates for benchmarking a nation's progress. To meet this need, the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2016 estimated global, regional, national, and, for selected locations, subnational cause-specific mortality beginning in the year 1980. Here we report an update to that study, making use of newly available data and improved methods. GBD 2017 provides a comprehensive assessment of cause-specific mortality for 282 causes in 195 countries and territories from 1980 to 2017.

METHODS

The causes of death database is composed of vital registration (VR), verbal autopsy (VA), registry, survey, police, and surveillance data. GBD 2017 added ten VA studies, 127 country-years of VR data, 502 cancer-registry country-years, and an additional surveillance country-year. Expansions of the GBD cause of death hierarchy resulted in 18 additional causes estimated for GBD 2017. Newly available data led to subnational estimates for five additional countries-Ethiopia, Iran, New Zealand, Norway, and Russia. Deaths assigned International Classification of Diseases (ICD) codes for non-specific, implausible, or intermediate causes of death were reassigned to underlying causes by redistribution algorithms that were incorporated into uncertainty estimation. We used statistical modelling tools developed for GBD, including the Cause of Death Ensemble model (CODEm), to generate cause fractions and cause-specific death rates for each location, year, age, and sex. Instead of using UN estimates as in previous versions, GBD 2017 independently estimated population size and fertility rate for all locations. Years of life lost (YLLs) were then calculated as the sum of each death multiplied by the standard life expectancy at each age. All rates reported here are age-standardised.

FINDINGS

At the broadest grouping of causes of death (Level 1), non-communicable diseases (NCDs) comprised the greatest fraction of deaths, contributing to 73·4% (95% uncertainty interval [UI] 72·5-74·1) of total deaths in 2017, while communicable, maternal, neonatal, and nutritional (CMNN) causes accounted for 18·6% (17·9-19·6), and injuries 8·0% (7·7-8·2). Total numbers of deaths from NCD causes increased from 2007 to 2017 by 22·7% (21·5-23·9), representing an additional 7·61 million (7·20-8·01) deaths estimated in 2017 versus 2007. The death rate from NCDs decreased globally by 7·9% (7·0-8·8). The number of deaths for CMNN causes decreased by 22·2% (20·0-24·0) and the death rate by 31·8% (30·1-33·3). Total deaths from injuries increased by 2·3% (0·5-4·0) between 2007 and 2017, and the death rate from injuries decreased by 13·7% (12·2-15·1) to 57·9 deaths (55·9-59·2) per 100 000 in 2017. Deaths from substance use disorders also increased, rising from 284 000 deaths (268 000-289 000) globally in 2007 to 352 000 (334 000-363 000) in 2017. Between 2007 and 2017, total deaths from conflict and terrorism increased by 118·0% (88·8-148·6). A greater reduction in total deaths and death rates was observed for some CMNN causes among children younger than 5 years than for older adults, such as a 36·4% (32·2-40·6) reduction in deaths from lower respiratory infections for children younger than 5 years compared with a 33·6% (31·2-36·1) increase in adults older than 70 years. Globally, the number of deaths was greater for men than for women at most ages in 2017, except at ages older than 85 years. Trends in global YLLs reflect an epidemiological transition, with decreases in total YLLs from enteric infections, respiratory infections and tuberculosis, and maternal and neonatal disorders between 1990 and 2017; these were generally greater in magnitude at the lowest levels of the Socio-demographic Index (SDI). At the same time, there were large increases in YLLs from neoplasms and cardiovascular diseases. YLL rates decreased across the five leading Level 2 causes in all SDI quintiles. The leading causes of YLLs in 1990-neonatal disorders, lower respiratory infections, and diarrhoeal diseases-were ranked second, fourth, and fifth, in 2017. Meanwhile, estimated YLLs increased for ischaemic heart disease (ranked first in 2017) and stroke (ranked third), even though YLL rates decreased. Population growth contributed to increased total deaths across the 20 leading Level 2 causes of mortality between 2007 and 2017. Decreases in the cause-specific mortality rate reduced the effect of population growth for all but three causes: substance use disorders, neurological disorders, and skin and subcutaneous diseases.

INTERPRETATION

Improvements in global health have been unevenly distributed among populations. Deaths due to injuries, substance use disorders, armed conflict and terrorism, neoplasms, and cardiovascular disease are expanding threats to global health. For causes of death such as lower respiratory and enteric infections, more rapid progress occurred for children than for the oldest adults, and there is continuing disparity in mortality rates by sex across age groups. Reductions in the death rate of some common diseases are themselves slowing or have ceased, primarily for NCDs, and the death rate for selected causes has increased in the past decade.

FUNDING

Bill & Melinda Gates Foundation.

Global, regional, and national incidence, prevalence, and years lived with disability for 354 diseases and injuries for 195 countries and territories, 1990-2017: a systematic analysis for the Global Burden of Disease Study 2017

BACKGROUND

The Global Burden of Diseases, Injuries, and Risk Factors Study 2017 (GBD 2017) includes a comprehensive assessment of incidence, prevalence, and years lived with disability (YLDs) for 354 causes in 195 countries and territories from 1990 to 2017. Previous GBD studies have shown how the decline of mortality rates from 1990 to 2016 has led to an increase in life expectancy, an ageing global population, and an expansion of the non-fatal burden of disease and injury. These studies have also shown how a substantial portion of the world's population experiences non-fatal health loss with considerable heterogeneity among different causes, locations, ages, and sexes. Ongoing objectives of the GBD study include increasing the level of estimation detail, improving analytical strategies, and increasing the amount of high-quality data.

METHODS

We estimated incidence and prevalence for 354 diseases and injuries and 3484 sequelae. We used an updated and extensive body of literature studies, survey data, surveillance data, inpatient admission records, outpatient visit records, and health insurance claims, and additionally used results from cause of death models to inform estimates using a total of 68 781 data sources. Newly available clinical data from India, Iran, Japan, Jordan, Nepal, China, Brazil, Norway, and Italy were incorporated, as well as updated claims data from the USA and new claims data from Taiwan (province of China) and Singapore. We used DisMod-MR 2.1, a Bayesian meta-regression tool, as the main method of estimation, ensuring consistency between rates of incidence, prevalence, remission, and cause of death for each condition. YLDs were estimated as the product of a prevalence estimate and a disability weight for health states of each mutually exclusive sequela, adjusted for comorbidity. We updated the Socio-demographic Index (SDI), a summary development indicator of income per capita, years of schooling, and total fertility rate. Additionally, we calculated differences between male and female YLDs to identify divergent trends across sexes. GBD 2017 complies with the Guidelines for Accurate and Transparent Health Estimates Reporting.

FINDINGS

Globally, for females, the causes with the greatest age-standardised prevalence were oral disorders, headache disorders, and haemoglobinopathies and haemolytic anaemias in both 1990 and 2017. For males, the causes with the greatest age-standardised prevalence were oral disorders, headache disorders, and tuberculosis including latent tuberculosis infection in both 1990 and 2017. In terms of YLDs, low back pain, headache disorders, and dietary iron deficiency were the leading Level 3 causes of YLD counts in 1990, whereas low back pain, headache disorders, and depressive disorders were the leading causes in 2017 for both sexes combined. All-cause age-standardised YLD rates decreased by 3·9% (95% uncertainty interval [UI] 3·1-4·6) from 1990 to 2017; however, the all-age YLD rate increased by 7·2% (6·0-8·4) while the total sum of global YLDs increased from 562 million (421-723) to 853 million (642-1100). The increases for males and females were similar, with increases in all-age YLD rates of 7·9% (6·6-9·2) for males and 6·5% (5·4-7·7) for females. We found significant differences between males and females in terms of age-standardised prevalence estimates for multiple causes. The causes with the greatest relative differences between sexes in 2017 included substance use disorders (3018 cases [95% UI 2782-3252] per 100 000 in males vs s1400 [1279-1524] per 100 000 in females), transport injuries (3322 [3082-3583] vs 2336 [2154-2535]), and self-harm and interpersonal violence (3265 [2943-3630] vs 5643 [5057-6302]).

INTERPRETATION

Global all-cause age-standardised YLD rates have improved only slightly over a period spanning nearly three decades. However, the magnitude of the non-fatal disease burden has expanded globally, with increasing numbers of people who have a wide spectrum of conditions. A subset of conditions has remained globally pervasive since 1990, whereas other conditions have displayed more dynamic trends, with different ages, sexes, and geographies across the globe experiencing varying burdens and trends of health loss. This study emphasises how global improvements in premature mortality for select conditions have led to older populations with complex and potentially expensive diseases, yet also highlights global achievements in certain domains of disease and injury.

FUNDING

Bill & Melinda Gates Foundation.

Global, regional, and national age-sex-specific mortality for 282 causes of death in 195 countries and territories, 1980-2017: a systematic analysis for the Global Burden of Disease Study 2017

BACKGROUND

Global development goals increasingly rely on country-specific estimates for benchmarking a nation's progress. To meet this need, the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2016 estimated global, regional, national, and, for selected locations, subnational cause-specific mortality beginning in the year 1980. Here we report an update to that study, making use of newly available data and improved methods. GBD 2017 provides a comprehensive assessment of cause-specific mortality for 282 causes in 195 countries and territories from 1980 to 2017.

METHODS

The causes of death database is composed of vital registration (VR), verbal autopsy (VA), registry, survey, police, and surveillance data. GBD 2017 added ten VA studies, 127 country-years of VR data, 502 cancer-registry country-years, and an additional surveillance country-year. Expansions of the GBD cause of death hierarchy resulted in 18 additional causes estimated for GBD 2017. Newly available data led to subnational estimates for five additional countries-Ethiopia, Iran, New Zealand, Norway, and Russia. Deaths assigned International Classification of Diseases (ICD) codes for non-specific, implausible, or intermediate causes of death were reassigned to underlying causes by redistribution algorithms that were incorporated into uncertainty estimation. We used statistical modelling tools developed for GBD, including the Cause of Death Ensemble model (CODEm), to generate cause fractions and cause-specific death rates for each location, year, age, and sex. Instead of using UN estimates as in previous versions, GBD 2017 independently estimated population size and fertility rate for all locations. Years of life lost (YLLs) were then calculated as the sum of each death multiplied by the standard life expectancy at each age. All rates reported here are age-standardised.

FINDINGS

At the broadest grouping of causes of death (Level 1), non-communicable diseases (NCDs) comprised the greatest fraction of deaths, contributing to 73·4% (95% uncertainty interval [UI] 72·5-74·1) of total deaths in 2017, while communicable, maternal, neonatal, and nutritional (CMNN) causes accounted for 18·6% (17·9-19·6), and injuries 8·0% (7·7-8·2). Total numbers of deaths from NCD causes increased from 2007 to 2017 by 22·7% (21·5-23·9), representing an additional 7·61 million (7·20-8·01) deaths estimated in 2017 versus 2007. The death rate from NCDs decreased globally by 7·9% (7·0-8·8). The number of deaths for CMNN causes decreased by 22·2% (20·0-24·0) and the death rate by 31·8% (30·1-33·3). Total deaths from injuries increased by 2·3% (0·5-4·0) between 2007 and 2017, and the death rate from injuries decreased by 13·7% (12·2-15·1) to 57·9 deaths (55·9-59·2) per 100 000 in 2017. Deaths from substance use disorders also increased, rising from 284 000 deaths (268 000-289 000) globally in 2007 to 352 000 (334 000-363 000) in 2017. Between 2007 and 2017, total deaths from conflict and terrorism increased by 118·0% (88·8-148·6). A greater reduction in total deaths and death rates was observed for some CMNN causes among children younger than 5 years than for older adults, such as a 36·4% (32·2-40·6) reduction in deaths from lower respiratory infections for children younger than 5 years compared with a 33·6% (31·2-36·1) increase in adults older than 70 years. Globally, the number of deaths was greater for men than for women at most ages in 2017, except at ages older than 85 years. Trends in global YLLs reflect an epidemiological transition, with decreases in total YLLs from enteric infections, respiratory infections and tuberculosis, and maternal and neonatal disorders between 1990 and 2017; these were generally greater in magnitude at the lowest levels of the Socio-demographic Index (SDI). At the same time, there were large increases in YLLs from neoplasms and cardiovascular diseases. YLL rates decreased across the five leading Level 2 causes in all SDI quintiles. The leading causes of YLLs in 1990-neonatal disorders, lower respiratory infections, and diarrhoeal diseases-were ranked second, fourth, and fifth, in 2017. Meanwhile, estimated YLLs increased for ischaemic heart disease (ranked first in 2017) and stroke (ranked third), even though YLL rates decreased. Population growth contributed to increased total deaths across the 20 leading Level 2 causes of mortality between 2007 and 2017. Decreases in the cause-specific mortality rate reduced the effect of population growth for all but three causes: substance use disorders, neurological disorders, and skin and subcutaneous diseases.

INTERPRETATION

Improvements in global health have been unevenly distributed among populations. Deaths due to injuries, substance use disorders, armed conflict and terrorism, neoplasms, and cardiovascular disease are expanding threats to global health. For causes of death such as lower respiratory and enteric infections, more rapid progress occurred for children than for the oldest adults, and there is continuing disparity in mortality rates by sex across age groups. Reductions in the death rate of some common diseases are themselves slowing or have ceased, primarily for NCDs, and the death rate for selected causes has increased in the past decade.

FUNDING

Bill & Melinda Gates Foundation.

Global, regional, and national incidence, prevalence, and years lived with disability for 354 diseases and injuries for 195 countries and territories, 1990-2017: a systematic analysis for the Global Burden of Disease Study 2017

BACKGROUND

The Global Burden of Diseases, Injuries, and Risk Factors Study 2017 (GBD 2017) includes a comprehensive assessment of incidence, prevalence, and years lived with disability (YLDs) for 354 causes in 195 countries and territories from 1990 to 2017. Previous GBD studies have shown how the decline of mortality rates from 1990 to 2016 has led to an increase in life expectancy, an ageing global population, and an expansion of the non-fatal burden of disease and injury. These studies have also shown how a substantial portion of the world's population experiences non-fatal health loss with considerable heterogeneity among different causes, locations, ages, and sexes. Ongoing objectives of the GBD study include increasing the level of estimation detail, improving analytical strategies, and increasing the amount of high-quality data.

METHODS

We estimated incidence and prevalence for 354 diseases and injuries and 3484 sequelae. We used an updated and extensive body of literature studies, survey data, surveillance data, inpatient admission records, outpatient visit records, and health insurance claims, and additionally used results from cause of death models to inform estimates using a total of 68 781 data sources. Newly available clinical data from India, Iran, Japan, Jordan, Nepal, China, Brazil, Norway, and Italy were incorporated, as well as updated claims data from the USA and new claims data from Taiwan (province of China) and Singapore. We used DisMod-MR 2.1, a Bayesian meta-regression tool, as the main method of estimation, ensuring consistency between rates of incidence, prevalence, remission, and cause of death for each condition. YLDs were estimated as the product of a prevalence estimate and a disability weight for health states of each mutually exclusive sequela, adjusted for comorbidity. We updated the Socio-demographic Index (SDI), a summary development indicator of income per capita, years of schooling, and total fertility rate. Additionally, we calculated differences between male and female YLDs to identify divergent trends across sexes. GBD 2017 complies with the Guidelines for Accurate and Transparent Health Estimates Reporting.

FINDINGS

Globally, for females, the causes with the greatest age-standardised prevalence were oral disorders, headache disorders, and haemoglobinopathies and haemolytic anaemias in both 1990 and 2017. For males, the causes with the greatest age-standardised prevalence were oral disorders, headache disorders, and tuberculosis including latent tuberculosis infection in both 1990 and 2017. In terms of YLDs, low back pain, headache disorders, and dietary iron deficiency were the leading Level 3 causes of YLD counts in 1990, whereas low back pain, headache disorders, and depressive disorders were the leading causes in 2017 for both sexes combined. All-cause age-standardised YLD rates decreased by 3·9% (95% uncertainty interval [UI] 3·1-4·6) from 1990 to 2017; however, the all-age YLD rate increased by 7·2% (6·0-8·4) while the total sum of global YLDs increased from 562 million (421-723) to 853 million (642-1100). The increases for males and females were similar, with increases in all-age YLD rates of 7·9% (6·6-9·2) for males and 6·5% (5·4-7·7) for females. We found significant differences between males and females in terms of age-standardised prevalence estimates for multiple causes. The causes with the greatest relative differences between sexes in 2017 included substance use disorders (3018 cases [95% UI 2782-3252] per 100 000 in males vs s1400 [1279-1524] per 100 000 in females), transport injuries (3322 [3082-3583] vs 2336 [2154-2535]), and self-harm and interpersonal violence (3265 [2943-3630] vs 5643 [5057-6302]).

INTERPRETATION

Global all-cause age-standardised YLD rates have improved only slightly over a period spanning nearly three decades. However, the magnitude of the non-fatal disease burden has expanded globally, with increasing numbers of people who have a wide spectrum of conditions. A subset of conditions has remained globally pervasive since 1990, whereas other conditions have displayed more dynamic trends, with different ages, sexes, and geographies across the globe experiencing varying burdens and trends of health loss. This study emphasises how global improvements in premature mortality for select conditions have led to older populations with complex and potentially expensive diseases, yet also highlights global achievements in certain domains of disease and injury.

FUNDING

Bill & Melinda Gates Foundation.

Genomic and Transcriptomic Analysis of Hypercholesterolemic Rabbits: Progress and Perspectives

Rabbits (Oryctolagus cuniculus) are one of the most widely used animal models for the study of human lipid metabolism and atherosclerosis because they are more sensitive to a cholesterol diet than other experimental animals such as rodents. Currently, two hypercholesterolemic rabbit models are frequently used for atherosclerosis studies. One is a cholesterol-fed wild-type rabbit and the other is the Watanabe heritable hyperlipidemic (WHHL) rabbit, which is genetically deficient in low density lipoprotein (LDL) receptor function. Wild-type rabbits can be easily induced to develop severe hypercholesterolemia with a cholesterol-rich diet due to the marked increase in hepatically and intestinally derived remnant lipoproteins, called β-very low density lipoproteins (VLDL), which are rich in cholesteryl esters. WHHL rabbits are characterized by elevated plasma LDL levels on a standard chow diet, which resembles human familial hypercholesterolemia. Therefore, both rabbit models develop aortic and coronary atherosclerosis, but the elevated plasma cholesterol levels are caused by completely different mechanisms. In addition, cholesterol-fed rabbits but not WHHL rabbits exhibit different degrees of hepatosteatosis. Recently, we along with others have shown that there are many differentially expressed genes in the atherosclerotic lesions and livers of cholesterol-fed rabbits that are either significantly up- or down-regulated, compared with those in normal rabbits, including genes involved in the regulation of inflammation and lipid metabolism. Therefore, dietary cholesterol plays an important role not only in hypercholesterolemia and atherosclerosis but also in hepatosteatosis. In this review, we make an overview of the recent progress in genomic and transcriptomic analyses of hypercholesterolemic rabbits. These transcriptomic profiling data should provide novel insight into the relationship between hypercholesterolemia and atherosclerosis or hepatic dysfunction caused by dietary cholesterol.

Ideal cardiovascular health associated with fatty liver: Results from a multi-ethnic survey

BACKGROUND AND AIMS

Little is known about the role of liver enzymes as predictors of non-liver-related morbidity and mortality. The ideal cardiovascular health (CVH) score proposed by the American Heart Association (AHA) can be used to predict mortality and morbidity. We investigated the association of the CVH score with liver enzymes and the risk of non-alcoholic fatty liver disease (NAFLD) among US adults.

METHODS

By using the National Health and Nutrition Examination Survey database (cross-sectional), the CVH score was calculated as meeting ideal levels of the following components: 4 behaviors (smoking, body mass index, physical activity and diet adherence) and 3 factors (total cholesterol, blood pressure and fasting glucose).

RESULTS

Individuals with a higher CVH score ("better CVH") had a more favorable profile of liver biomarkers. Adjusted (for age, gender, race, poverty to income ratio, education, marital status and alcohol intake) linear regression indicated significant and negative associations between liver biomarkers and CVH score: (β = -0.069, p < 0.001) for alanine aminotransferase, (β = -0.095, p < 0.001), aspartate aminotransferase, (β = -0.067, p < 0.001), alkaline phosphatase and (β = -0.125, p < 0.001) and fatty liver index. In the logistic regression, with the same confounders, individuals with a higher CVH score had 12% less likelihood of NAFLD compared with those with a lower score. Furthermore, each CVH metric separately was inversely linked to the risk of NAFLD.

CONCLUSIONS

For the first time among US adults, our findings shed light on the role CVH on liver biomarkers.

Obesity-induced upregulation of miR-361-5p promotes hepatosteatosis through targeting Sirt1

OBJECTIVE

Obesity is associated with an increased risk of many metabolic disorders, including non-alcoholic fatty liver disease (NAFLD). However, the underlying mechanisms remain poorly understood. Recent studies have demonstrated that MicroRNA-mediated gene silencing plays an important role in hepatic triglyceride (TG) metabolism. In the present study, we aimed to investigate the pathological function of miR-361-5p in the development of NAFLD.

METHODS

Expression levels of miR-361-5p was determined by quantitative real-time PCR in livers of obese mice and NAFLD patients. Liver tissues from mice with miR-361-5p overexpression or inhibition were collected and analyzed by TG contents, gene expression profile.

RESULTS

Expression of miR-361-5p was increased in the livers of two obese mouse models and NAFLD subjects. Overexpression of miR-361-5p in C57BL/6 mice led to hepatosteatosis, whereas inhibition of miR-361-5p expression in db/db mice improved TG accumulation and insulin sensitivity. Mechanistically, we identified Sirt1 as a direct target gene of miR-361-5p and re-introduction of Sirt1 largely abolished the metabolic action of miR-361-5p.

CONCLUSIONS

Our results demonstrated the role of miR-361-5p in the regulation of hepatic TG homeostasis, which may provide potential therapeutic target for hepatosteatosis.

Predictors of advanced fibrosis in non-cirrhotic non-alcoholic fatty liver disease in Germany

BACKGROUND

Advanced fibrosis has been established as the most important predictor of overall mortality in patients with non-alcoholic fatty liver disease (NAFLD). In contrast to cirrhosis, advanced, non-cirrhotic NAFLD is difficult to identify and data from Germany are lacking.

AIM

To identify clinical factors associated with advanced, non-cirrhotic fibrosis.

METHODS

Patients were recruited in the prospectively enrolling European NAFLD Registry. Clinical characteristics and the performance of non-invasive surrogate scores compared with vibration-controlled transient elastography are reported.

RESULTS

Two hundred and sixty-one patients with non-cirrhotic NAFLD on liver biopsy (mean age 51 years, equal sex distribution) were included. The prevalence of stage 3 fibrosis on liver biopsy was 15.7%. These patients were significantly older (57 vs 50 years, P < 0.01), had a higher body mass index (32.3 vs 30.5, P < 0.05), and more frequent arterial hypertension (78% vs 50%, P = 0.001) and type 2 diabetes (61% vs 24.1%, P < 0.001). On multivariate logistic regression, diabetes (OR = 4.68, 95% CI 2.17-10.10) and hypertension (OR = 2.91, 95% CI 1.12-7.18) were independent predictors of advanced fibrosis. Comedication included metformin in 50% and insulin in 33% of patients with diabetes. Despite the presence of cardiovascular risk factors, the use of statins was low. Liver stiffness measurement identified advanced fibrosis with an AUROC of 0.81 (95% CI 0.72-0.91). The performance of NAFLD fibrosis score, Fibrosis-4, and AST to platelet ratio index were lower with AUCs of 0.74, 0.71, and 0.67, respectively.

CONCLUSIONS

The prevalence of metabolic comorbidities in a German population with non-cirrhotic biopsy-proven NAFLD is high. While the examined scores exhibit an acceptable specificity, liver stiffness measurement appeared to be superior to blood-based non-invasive surrogate scores in ruling out advanced fibrosis.

SRY-Box Containing Gene 4 Promotes Liver Steatosis by Upregulation of SREBP-1c

Obesity is usually associated with an increased risk of nonalcoholic fatty liver disease that is characterized by accumulation of excessive triglyceride (TG) in hepatocytes. However, the factors involved in the obesity-induced hepatosteatosis are poorly defined. Here, we report that SRY-box containing gene 4 (Sox4), a transcription factor that regulates cell proliferation and differentiation, plays an important role in hepatic TG metabolism. Sox4 expression levels are markedly upregulated in livers of obese rodents and humans. Adenovirus-medicated overexpression of Sox4 in the livers of lean mice promotes liver steatosis, whereas liver-specific knockdown of Sox4 ameliorates TG accumulation and improves insulin resistance in obese mice. At the molecular level, we show that Sox4 could directly control the transcription of SREBP-1c gene through binding to its proximal promoter region. Thus, we have identified Sox4 as an important component of hepatic TG metabolism.

An update on the recent advances in antifibrotic therapy

Chronic injury to the liver, such as viral hepatitis, alcoholism, non-alcoholic fatty liver disease (NAFLD) or nonalcoholic steatohepatitis (NASH), promotes extracellular matrix deposition and organ scarring, termed hepatic fibrosis. Fibrosis might progress to cirrhosis and predisposes to hepatocellular carcinoma (HCC), but is also associated with extrahepatic morbidity and mortality in NAFLD/NASH. The improved understanding of pathogenic mechanisms underlying chronic inflammation and fibrogenesis in the liver prompted recent advances in antifibrotic therapies. Areas covered: We review recent advances in antifibrotic therapy, of which most are currently tested in clinical trials for NAFLD or NASH. This explains the manifold metabolic pathways as antifibrotic targets, including farnesoid X receptor (FXR) agonism (obeticholic acid, nonsteroidal FXR agonists), acetyl-CoA carboxylase inhibition, peroxisome proliferator-activator receptor agonism (elafibranor, lanifibranor, saroglitazar), and fibroblast growth factor (FGF)-21 or FGF-19 activation. Other antifibrotic drug candidates target cell death or inflammation, such as caspase (emricasan) or ASK1 inhibitors (selonsertib), galectin-3 inhibitors and reducing inflammatory macrophage recruitment by blocking chemokine receptors CCR2/CCR5 (cenicriviroc). Expert commentary: The tremendous advances in translational and clinical research fuels the hope for efficacious antifibrotic therapies within the next 5 years. Very likely, a combination of etiology-specific, metabolic, anti-inflammatory, and direct antifibrotic interventions will be most effective.

Hypothyroidism and nonalcoholic fatty liver disease - a chance association?

Background Nonalcoholic fatty liver disease (NAFLD) defines the clinical-pathological spectrum of hepatic lipotoxicity, which may progress to hepatic fibrosis and its complications. Thyroid hormone is a master regulator of cell metabolism and body fat distribution. Whether hypothyroidism is associated or not with an increased risk of developing NAFLD and its fibrotic progression is both clinically and physiopathologically relevant. Indeed, answering this research question would carry major pathogenic and therapeutic implications. Method PubMed database was searched using relevant key-words such as hypothyroidism; NAFLD; nonalcoholic steatohepatitis; cirrhosis; hepatocellular carcinoma; epidemiology; pathogenesis; natural history. The epidemiological studies and the meta-analyses published so far were identified as well as those studies addressing the physiopathology underlying this association. Results Many observational studies have investigated the association between either subclinical or overt hypothyroidism and NAFLD. Data are conflicting: some original and meta-analytical studies demonstrated that hypothyroidism, (mainly subclinical hypothyroidism), was common, occurring in approximately 25% of individuals with imaging-defined or biopsy-proven NAFLD; other studies, however, failed to identify a significant association between hypothyroidism and NAFLD. Moreover, such an association is biologically plausible based on the specific physiopathological impact of thyroid hormone and thyroid stimulating hormone (TSH) on metabolism of hepatocytes and accumulation and distribution of body fat. Conclusions The findings from the present review support a significant association between primary hypothyroidism and risk of development and progression of NAFLD. However, further studies evaluating the relative importance of subclinical versus overt hypothyroidism as well as addressing the mechanisms underlying the association of hypothyroidism with NAFLD are eagerly awaited.

A Modular Ionophore Platform for Liver-Directed Copper Supplementation in Cells and Animals

Copper deficiency is implicated in a variety of genetic, neurological, cardiovascular, and metabolic diseases. Current approaches for addressing copper deficiency rely on generic copper supplementation, which can potentially lead to detrimental off-target metal accumulation in unwanted tissues and subsequently trigger oxidative stress and damage cascades. Here we present a new modular platform for delivering metal ions in a tissue-specific manner and demonstrate liver-targeted copper supplementation as a proof of concept of this strategy. Specifically, we designed and synthesized an N-acetylgalactosamine-functionalized ionophore, Gal-Cu(gtsm), to serve as a copper-carrying "Trojan Horse" that targets liver-localized asialoglycoprotein receptors (ASGPRs) and releases copper only after being taken up by cells, where the reducing intracellular environment triggers copper release from the ionophore. We utilized a combination of bioluminescence imaging and inductively coupled plasma mass spectrometry assays to establish ASGPR-dependent copper accumulation with this reagent in both liver cell culture and mouse models with minimal toxicity. The modular nature of our synthetic approach presages that this platform can be expanded to deliver a broader range of metals to specific cells, tissues, and organs in a more directed manner to treat metal deficiency in disease.

Diethyldithiocarbamate, an anti-abuse drug, alleviates steatohepatitis and fibrosis in rodents through modulating lipid metabolism and oxidative stress

BACKGROUND AND PURPOSE

Diethyldithiocarbamate (DDC) is a major metabolite of disulfiram that is a potential drug for alcoholism treatment. In the present study, we attempted to explore the possible effect of DDC on non-alcoholic fatty liver disease (NAFLD) and related fibrosis in vivo.

EXPERIMENTAL APPROACH

C57BL/6 mice and Sprague Dawley (SD) rats received a methionine/choline-deficient (MCD) diet to establish the model of NAFLD with or without DDC treatment. The livers and serum were assessed for histological changes and parameters related to lipid metabolism, liver injury, inflammation and fibrosis. Apoptosis and macrophage related markers were assessed by immunohistochemistry (IHC).

KEY RESULTS

DDC significantly reduced hepatic steatosis in rats with NAFLD, induced by the MCD diet. DDC reduced the oxidative stress and endoplasmic reticulum stress-related parameters in mice with non-alcoholic steatohepatitis, induced by the MCD diet. IHC for Bax and cleaved caspase-3 showed that DDC inhibited the apoptosis of hepatocytes in the liver. DDC significantly reduced ballooning and Mallory-Denk bodies (MDB) in hepatocytes, accompanied by suppression of serum alanine aminotransferase, aspartate aminotransferase and MDB formation-related genes. DDC significantly alleviated hepatic inflammation, accompanied by suppression of inflammation-related genes. DDC suppressed the infiltration of macrophages, particularly inducible NOS-positive pro-inflammatory macrophages. In addition, DDC significantly alleviated liver fibrosis. Microarray analyses showed that DDC strongly affected lipid metabolism and oxidative stress-related processes and pathways.

CONCLUSION AND IMPLICATIONS

DDC improves hepatic steatosis, ballooning, inflammation and fibrosis in rodent models of NAFLD through modulating lipid metabolism and oxidative stress.

Adapted Immune Responses of Myeloid-Derived Cells in Fatty Liver Disease

Non-alcoholic fatty liver disease (NAFLD) is considered to be one of the most frequent chronic liver diseases worldwide and is associated with an increased risk of developing liver cirrhosis and hepatocellular carcinoma. Hepatic macrophages, mainly comprising monocyte derived macrophages and tissue resident Kupffer cells, are characterized by a high diversity and plasticity and act as key regulators during NAFLD progression, in conjunction with other infiltrating myeloid cells like neutrophils or dendritic cells. The activation and polarization of myeloid immune cells is influenced by dietary components, inflammatory signals like danger-associated molecular patterns (DAMPs) or cytokines as well as gut-derived inflammatory factors such as pathogen-associated molecular patterns (PAMPs). The functionality of myeloid leukocytes in the liver is directly linked to their inflammatory polarization, which is shaped by local and systemic inflammatory mediators such as cytokines, chemokines, PAMPs, and DAMPs. These environmental signals provoke intracellular adaptations in myeloid cells, including inflammasome and transcription factor activation, inflammatory signaling pathways, or switches in cellular metabolism. Dietary changes and obesity also promote a dysbalance in intestinal microbiota, which can facilitate intestinal permeability and bacterial translocation. The aim of this review is to highlight recent findings on the activating pathways of innate immune cells during the progression of NAFLD, dissecting local hepatic and systemic signals, dietary and metabolic factors as well as pathways of the gut-liver axis. Understanding the mechanism by which plasticity of myeloid-derived leukocytes is related to metabolic changes and NAFLD progression may provide options for new therapeutic approaches.

Gender differences in hepatocellular cancer: disparities in nonalcoholic fatty liver disease/steatohepatitis and liver transplantation

Aim:

Worldwide, hepatocellular cancer (HCC) is the fourth leading cause of cancer death and occurs 3 times more commonly in males than females. Current surveillance practices do not fully address gender differences in HCC.

Methods:

Clinical characteristics and survival were compared between males and females using a prospectively collected database of HCC patients.

Results:

In a cohort of 1206 patients, 307 (25%) were female who presented with older age, more non-alcoholic fatty liver disease/steatohepatitis (NAFLD/NASH), family history of HCC, and hypertension. Males (75%) were more likely to use alcohol and cigarettes. Females were more likely to undergo HCC surveillance, have smaller tumor size at diagnosis, and less vascular involvement. Males who met Milan criteria were more likely to undergo liver transplant than women who met the criteria. Median/mean survival was similar between the genders. Multivariate analysis showed that NAFLD/NASH was predictive of mortality for both males and females, age and smoking were predictive of mortality for males, and transplant was predictive of survival for males.

Conclusion:

Gender differences in HCC appear related to both behavioral risk factors and biologic factors. Older females with HCC have more NAFLD/NASH and may be overlooked by current surveillance guidelines. These gender disparities may lend support to future studies of gender-based HCC screening.

The Evolving Role of Liver Biopsy in Non-alcoholic Fatty Liver Disease

Evaluation patients with nonalcoholic steatohepatitis (NASH) imply the need of appropriate assessment of disease severity (i.e. the presence of nonalcoholic steatohepatitis (NASH)) as well as of the disease stage (i.e. the extent of liver fibrosis). Liver biopsy (LB) is still considered the gold standard for diagnosing NASH as well as for establishing the degree of liver fibrosis. However, due to its invasive nature and costs, use of LB should be restricted to selected patients and, according guidelines and expert opinion, indicated in the following scenarios: a) when LB will guide treatment, b) to confirm or exclude NAFLD in patients with conflicting clinical data, c) to increase patient's awareness about their disease, and improve engagement in their care and d) for inclusion in clinical trials. However, the role fo LB in NAFLD is evolving since when new and costly therapeutic agents become available, LB will be eventually necessary to make clinical decisions. The use of non-invasive tools (NITs) to assess steatosis, NASH and hepatic fibrosis is useful to triage NAFLD patients and decide in whom perform a LB.

Obeticholic Acid: A New Era in the Treatment of Nonalcoholic Fatty Liver Disease

The main treatments for patients with nonalcoholic fatty liver disease (NAFLD) are currently based on lifestyle changes, including ponderal decrease and dietary management. However, a subgroup of patients with nonalcoholic steatohepatitis (NASH), who are unable to modify their lifestyle successfully, may benefit from pharmaceutical support. Several drugs targeting pathogenic mechanisms of NAFLD have been evaluated in clinical trials for the treatment of NASH. Farnesoid X receptor (FXR) is a nuclear key regulator controlling several processes of the hepatic metabolism. NAFLD has been proven to be associated with abnormal FXR activity. Obeticholic acid (OCA) is a first-in-class selective FXR agonist with anticholestatic and hepato-protective properties. Currently, OCA is registered for the treatment of primary biliary cholangitis. However, promising effects of OCA on NASH and its metabolic features have been reported in several studies.

A higher flavonoid intake is associated with less likelihood of nonalcoholic fatty liver disease: results from a multiethnic study

Limited information exists on the impact of flavonoid intake on nonalcoholic fatty liver disease (NAFLD). We evaluated the link between flavonoid intake, liver tests and risk of NAFLD in a randomly selected sample of US adults (from the National Health and Nutrition Examination Survey, NHANES, 2005-2010). Of the 17,685 participants, 46.9% were men and 45.4% had NAFLD. NAFLD patients had a significantly lower mean flavonoid intake than healthy individuals (111.3±3.6 vs. 201.3±2.3 mg/d, respectively; P<.001). Fatty liver index (FLI) and serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT) were significantly higher in the first tertile (T1) of flavonoid intake compared with the highest tertile (T3: with the highest flavonoid intake) (FLI: 67.1 vs. 36.2, AST: 31.2 VS 26.8 U/L and, ALT: 34.2 vs. 24.2 U/L, respectively; P<.001 for all comparisons). Adjusted linear regression displayed significant and negative associations between FLI, AST, ALT and flavonoid intake (P<.001 for all comparisons). Multivariable logistic regression showed that the risk for NAFLD significantly decreased as flavonoid intake tertiles increased in a stepwise manner (odds ratio: 0.81, 95% confidence interval: 0.78-0.86). Moderation analysis revealed that C-reactive protein (CRP) strongly modulated the impact of flavonoid intake on FLI; participants with higher CRP levels benefited less from flavonoid intake compared with those with lower CRP concentrations. In conclusions, our results suggest a reverse significant association between flavonoid consumption, liver tests and the risk for NAFLD. Furthermore, CRP was shown to essentially moderate this relationship. These findings support recommendations for consumption of flavonoid-rich foods to prevent cardiometabolic diseases.

Agonism for the bile acid receptor GPBAR1 reverses liver and vascular damage in a mouse model of steatohepatitis

Nonalcoholic steatohepatitis (NASH) is associated with an increased risk of developing cardiovascular complications and mortality, suggesting that treatment of NASH might benefit from combined approaches that target the liver and the cardiovascular components of NASH. Using genetic and pharmacologic approaches, we show that G protein-coupled bile acid-activated receptor 1 (GPBAR1) agonism reverses liver and vascular damage in mouse models of NASH. NASH is associated with accelerated vascular inflammation representing an independent risk factor for development of cardiovascular diseases and cardiovascular-related mortality. GPBAR1, also known as TGR5, is a G protein-coupled receptor for secondary bile acids that reduces inflammation and promotes energy expenditure. Using genetic and pharmacologic approaches, we investigated whether GPBAR1 agonism by 6β-ethyl-3α,7β-dihydroxy-5β-cholan-24-ol (BAR501) reverses liver and vascular damage induced by exposure to a diet enriched in fat and fructose (HFD-F). Treating HFD-F mice with BAR501 reversed liver injury and promoted the browning of white adipose tissue in a Gpbar1-dependent manner. Feeding HFD-F resulted in vascular damage, as shown by the increased aorta intima-media thickness and increased expression of inflammatory genes (IL-6,TNF-α, iNOS, and F4/80) and adhesion molecules (VCAM, intercellular adhesion molecule-1, and endothelial selectin) in the aorta, while reducing the expression of genes involved in NO and hydrogen sulfide generation, severely altering vasomotor activities of aortic rings in an ex vivo assay. BAR501 reversed this pattern in a Gpbar1-dependent manner, highlighting a potential role for GPBAR1 agonism in treating the liver and vascular component of NASH.-Carino, A., Marchianò, S., Biagioli, M., Bucci, M., Vellecco, V., Brancaleone, V., Fiorucci, C., Zampella, A., Monti, M. C., Distrutti, E., Fiorucci, S. Agonism for the bile acid receptor GPBAR1 reverses liver and vascular damage in a mouse model of steatohepatitis.

Mitochondrial Stasis Reveals p62-Mediated Ubiquitination in Parkin-Independent Mitophagy and Mitigates Nonalcoholic Fatty Liver Disease

It is unknown what occurs if both mitochondrial division and fusion are completely blocked. Here, we introduced mitochondrial stasis by deleting two dynamin-related GTPases for division (Drp1) and fusion (Opa1) in livers. Mitochondrial stasis rescues liver damage and hypotrophy caused by the single knockout (KO). At the cellular level, mitochondrial stasis re-establishes mitochondrial size and rescues mitophagy defects caused by division deficiency. Using Drp1KO livers, we found that the autophagy adaptor protein p62/sequestosome-1-which is thought to function downstream of ubiquitination-promotes mitochondrial ubiquitination. p62 recruits two subunits of a cullin-RING ubiquitin E3 ligase complex, Keap1 and Rbx1, to mitochondria. Resembling Drp1KO, diet-induced nonalcoholic fatty livers enlarge mitochondria and accumulate mitophagy intermediates. Resembling Drp1Opa1KO, Opa1KO rescues liver damage in this disease model. Our data provide a new concept that mitochondrial stasis leads the spatial dimension of mitochondria to a stationary equilibrium and a new mechanism for mitochondrial ubiquitination in mitophagy.

Among Patients With NAFLD, Treatment of Dyslipidemia Does Not Reduce Cardiovascular Mortality

Dyslipidemia is one of the common risk factors for NAFLD and is associated with cardiovascular (CV) mortality, which is the most common cause of death in NAFLD. Lipid-lowering agents (LLAs) are used to reduce CV events in the general population. Our aim was to assess whether the use of LLAs in patients with NAFLD can reduce the risk of CV mortality. We used the third National Health and Nutrition Examination Survey mortality linked files. Mortality was determined from the National Death Index records through 2011. NAFLD was diagnosed by ultrasound after exclusion of other causes of liver disease. After inclusion and exclusion, the cohort consisted of 2,566 patients with NAFLD (45.8% < 45 years of age, 52.8% male, 75.4% white). Those who were taking LLAs were more likely to be older, non-Hispanic white, and had significantly higher rates of diabetes mellitus (DM), hyperlipidemia, hypertension, metabolic syndrome, and history of CV disease (CVD) (all P< 0.01). In our multivariate analysis, DM was an independent predictor of overall mortality (adjusted hazard ratio [aHR]: 1.79 [95% confidence interval (CI): 1.40-2.30]) and CV mortality (aHR: 1.89 [95% CI: 1.08-3.30]). History of CVD was associated with both overall (aHR: 2.03 [95% CI: 1.57-2.63]) and CV mortality (aHR: 3.69 [95% CI: 2.23-6.08]). In contrast, the use of statins and other LLAs was not associated with reduction in overall (aHR = 0.95 [95% CI: 0.37-2.44] and aHR = 1.43 [95% CI: 0.99-2.07]) and CV mortality (aHR = 1.20 [95% CI: 0.26-5.54] and aHR = 1.63 [95% CI: 0.70-3.76]). Conclusion: The use of statins and other LLAs did not reduce the increased risk of overall or CV mortality in NAFLD.

Association Between Primary Hypothyroidism and Nonalcoholic Fatty Liver Disease: A Systematic Review and Meta-Analysis

BACKGROUND

It is currently uncertain whether primary hypothyroidism is associated with nonalcoholic fatty liver disease (NAFLD). We performed a meta-analysis of relevant studies to quantify the magnitude of association between primary hypothyroidism and risk of NAFLD.

METHODS

We searched PubMed, Web of Science and Scopus databases from January 2000 to March 2018 using predefined keywords to identify observational cross-sectional, case-control, and longitudinal studies in which NAFLD was diagnosed by imaging or biopsy. Data from selected studies were extracted and meta-analysis was performed using random-effects modeling.

RESULTS

A total of 12 cross-sectional and 3 longitudinal studies enrolling 44,140 individuals were included in the final analysis. Hypothyroidism (defined either by self-reported history of hypothyroidism with use of levothyroxine replacement therapy or by presence of abnormal thyroid function tests) was associated with an increased risk of prevalent NAFLD (n = 12 studies; random-effects odds ratio 1.42 [95% confidence interval (CI) 1.15-1.77]; I² = 51.2%), independently of age, sex, body mass index and other common metabolic risk factors. The magnitude of risk paralleled the underlying severity of NAFLD histology (n = 3 studies; random-effects odds ratio 2.73 [CI 1.90-3.93]; I² = 0%), and tended to increase across the different definitions used for diagnosing hypothyroidism. Meta-analysis of data from the three longitudinal studies showed that subclinical hypothyroidism was not independently associated with risk of incident ultrasound-defined NAFLD over a median of 5 years (random-effects hazard ratio 1.29 [CI 0.89-1.86]; I² = 83.9%). Sensitivity analyses did not alter these findings. Funnel plot did not reveal significant publication bias.

CONCLUSIONS

This large and updated meta-analysis shows that the presence of variably defined hypothyroidism is significantly associated with the presence and severity of NAFLD. However, the observational design of the eligible studies does not allow for proving causality.

Association between nonalcoholic fatty liver disease and colorectal tumours in asymptomatic adults undergoing screening colonoscopy: a systematic review and meta-analysis

BACKGROUND

It is currently uncertain whether non-alcoholic fatty liver disease (NAFLD) is associated with an increased risk of colorectal tumours. We performed a meta-analysis of relevant observational studies to quantify the magnitude of the association between NAFLD and risk of colorectal adenomas and cancer.

METHODS

We searched PubMed, Scopus and Web of Science from January 2000 to November 2017 using pre-defined keywords to identify observational studies of asymptomatic adults undergoing screening colonoscopy, in which NAFLD was diagnosed by imaging or histology. Data from selected studies were extracted and meta-analysis was performed using random-effects modelling.

RESULTS

Eleven observational studies (8 cross-sectional and 3 longitudinal) with aggregate data on 91,124 asymptomatic adults (32.1% with NAFLD) of predominantly Asian descent accounting for a total of 14,911 colorectal adenomas and 1684 cancers were included in the final analysis. NAFLD was associated with an increased risk of prevalent colorectal adenomas (n = 7 studies using liver imaging techniques; random-effects odds ratio [OR] 1.28, 95% CI 1.11-1.48; I² = 82.9% or n = 1 study using liver biopsy; random-effects OR 1.61, 95% CI 0.90-2.89) and cancer (n = 4 studies using liver imaging techniques; random-effects OR 1.56, 95% CI 1.25-1.94; I² = 65.6% or n = 1 study using liver biopsy; random-effects OR 3.04, 95% CI 1.29-7.18). NAFLD was also associated with an increased risk of incident colorectal adenomas (n = 3 studies; random-effects hazard ratio [HR] 1.42, 95% CI 1.18-1.72; I² = 0%) and cancer (n = 1 study; random-effects HR 3.08, 95% CI 1.02-9.03). These risks were independent of age, sex, smoking, body mass index and diabetes (or metabolic syndrome). Sensitivity analyses did not alter these findings. Funnel plot and Egger's test did not reveal significant publication bias.

CONCLUSIONS

This meta-analysis of observational studies (involving asymptomatic individuals of predominantly Asian descent undergoing screening colonoscopy) suggests that NAFLD (detected by imaging or biopsy) is independently associated with a moderately increased prevalence and incidence of colorectal adenomas and cancer. However, the observational design of the studies does not allow for proving causality, and the possibility of residual confounding by some unmeasured factors cannot be ruled out. More prospective studies, particularly in European and American individuals, and mechanistic studies are required to better understand the association between NAFLD and colonic carcinogenesis.

Obesity in Type 1 Diabetes: Pathophysiology, Clinical Impact, and Mechanisms

There has been an alarming increase in the prevalence of obesity in people with type 1 diabetes in recent years. Although obesity has long been recognized as a major risk factor for the development of type 2 diabetes and a catalyst for complications, much less is known about the role of obesity in the initiation and pathogenesis of type 1 diabetes. Emerging evidence suggests that obesity contributes to insulin resistance, dyslipidemia, and cardiometabolic complications in type 1 diabetes. Unique therapeutic strategies may be required to address these comorbidities within the context of intensive insulin therapy, which promotes weight gain. There is an urgent need for clinical guidelines for the prevention and management of obesity in type 1 diabetes. The development of these recommendations will require a transdisciplinary research strategy addressing metabolism, molecular mechanisms, lifestyle, neuropsychology, and novel therapeutics. In this review, the prevalence, clinical impact, energy balance physiology, and potential mechanisms of obesity in type 1 diabetes are described, with a special focus on the substantial gaps in knowledge in this field. Our goal is to provide a framework for the evidence base needed to develop type 1 diabetes-specific weight management recommendations that account for the competing outcomes of glycemic control and weight management.

Hospitalizations for Cardiovascular Disease After Liver Transplantation in the United States

Cardiovascular disease (CVD) is a leading cause of post-liver transplant death, and variable care patterns may affect outcomes. We aimed to describe epidemiology and outcomes of inpatient CVD care across US hospitals. Using a merged data set from the 2002-2011 Nationwide Inpatient Sample and the American Hospital Association Annual Survey, we evaluated liver transplant patients admitted primarily with myocardial infarction (MI), stroke (cerebrovascular accident [CVA]), congestive heart failure (CHF), dysrhythmias, cardiac arrest (CA), or malignant hypertension. Patient-level data include demographics, Charlson comorbidity index, and CVD diagnoses. Facility-level variables included ownership status, payer-mix, hospital resources, teaching status, and physician/nursing-to-bed ratios. We used generalized estimating equations to evaluate patient- and hospital-level factors associated with mortality. There were 4763 hospitalizations that occurred in 153 facilities (transplant hospitals, n = 80). CVD hospitalizations increased overall by 115% over the decade (P < 0.01). CVA and MI declined over time (both P < 0.05), but CHF and dysrhythmia grew significantly (both P < 0.03); a total of 19% of hospitalizations were for multiple CVD diagnoses. Transplant hospitals had lower comorbidity patients (P < 0.001) and greater resource intensity including presence of cardiac intensive care unit, interventional radiology, operating rooms, teaching status, and nursing density (all P < 0.01). Transplant and nontransplant hospitals had similar unadjusted mortality (overall, 3.9%, P = 0.55; by diagnosis, all P > 0.07). Transplant hospitals had significantly longer overall length of stay, higher total costs, and more high-cost hospitalizations (all P < 0.05). After risk adjustment, transplant hospitals were associated with higher mortality and high-cost hospitalizations. In conclusion, CVD after liver transplant is evolving and responsible for growing rates of inpatient care. Transplant hospitals are associated with poor outcomes, even after risk adjustment for patient and hospital characteristics, which may be attributable to selective referral of certain patient phenotypes but could also be related to differences in quality of care. Further study is warranted.

When to Initiate Weight Loss Medications in the NAFLD Population

Nonalcoholic fatty liver disease (NAFLD) is characterized by histological evidence of hepatic steatosis, lobular inflammation, ballooning degeneration and hepatic fibrosis in the absence of significant alcohol use and other known causes of chronic liver diseases. NAFLD is subdivided into nonalcoholic fatty liver (NAFL) and nonalcoholic steatohepatitis (NASH). NAFL is generally benign but can progress to NASH, which carries a higher risk of adverse outcomes including cirrhosis, end-stage liver disease, hepatocellular carcinoma and death if liver transplantation is not pursued in a timely fashion. Currently, lifestyle modifications including healthy diet and increased physical activity/exercise culminating in weight loss of 5% to >10% is the cornerstone of treatment intervention for patients with NAFLD. Patients with NAFLD who fail to obtain this goal despite the help of dietitians and regimented exercise programs are left in a purgatory state and remain at risk of developing NASH-related advance fibrosis. For such patients with NAFLD who are overweight and obese, healthcare providers should consider a trial of FDA-approved anti-obesity medications as adjunct therapy to provide further preventative and therapeutic options as an effort to reduce the risk of NAFLD-related disease progression.

Branched chain amino acid transaminase 1 (BCAT1) is overexpressed and hypomethylated in patients with non-alcoholic fatty liver disease who experience adverse clinical events: A pilot study

Background and objectives

Although the burden of non-alcoholic fatty liver disease (NAFLD) continues to increase worldwide, genetic factors predicting progression to cirrhosis and decompensation in NAFLD remain poorly understood. We sought to determine whether gene expression profiling was associated with clinical decompensation and death in patients with NAFLD, and to assess whether altered DNA methylation contributes to these changes in gene expression.

Methods

We performed a retrospective analysis of 86 patients in the Duke NAFLD Clinical Database and Biorepository with biopsy-proven NAFLD whose liver tissue was previously evaluated for gene expression and DNA methylation using array based technologies. We assessed the prospective development of liver and cardiovascular disease related outcomes, including hepatic decompensation as identified by the development of ascites, hepatic encephalopathy, hepatocellular carcinoma, or variceal bleeding as well as stroke and myocardial infarction via medical chart review.

Results

Of the 86 patients, 47 had F0-F1 fibrosis and 39 had F3-F4 fibrosis at index liver biopsy. Gene expression probe sets (n = 54,675) were analyzed; 42 genes showed significant differential expression (p<0.05) and a two-fold change in expression between patients with and without any outcome. Two expression probes of the branched chain amino-acid transaminase 1 (BCAT1) gene were upregulated (p = 0.02; fold change 2.1 and 2.2 respectively) in patients with a clinical outcome. Methylation of three of the 34 BCAT1 CpG methylation probes were significantly inversely correlated with BCAT1 expression specific to the probes predictive of clinical deterioration.

Conclusion

We found differential gene expression, correlated to changes in DNA methylation, at multiple BCAT1 loci in patients with cardiovascular outcomes and/or hepatic decompensation. BCAT1 catalyzes the transformation of alpha-ketoglutarate to glutamate and has been linked to the presence and severity of NAFLD, possibly through derangements in the balance between glutamate and alpha-ketoglutarate. Given the potential for BCAT1 to identify patients at risk for poor outcomes, and the potential therapeutic implications, these results should be validated in larger prospective studies.

Involvement of G protein-coupled receptor kinase 2 (GRK2) in the development of non-alcoholic steatosis and steatohepatitis in mice and humans

Insulin resistance (IR) and obesity are important risk factors for non-alcoholic fatty liver disease (NAFLD). G protein-coupled receptor kinase 2 (GRK2) is involved in the development of IR and obesity in vivo. However, its possible contribution to NAFLD and/or non-alcoholic steatohepatitis (NASH) independently of its role on IR or fat mass accretion has not been explored. Here, we used wild-type (WT) or GRK2 hemizygous (GRK2±) mice fed a high-fat diet (HFD) or a methionine and choline-deficient diet (MCD) as a model of NASH independent of adiposity and IR. GRK2± mice were protected from HFD-induced NAFLD. Moreover, MCD feeding caused an increased in triglyceride content and liver-to-body weight ratio in WT mice, features that were attenuated in GRK2± mice. According to their NAFLD activity score, MCD-fed GRK2± mice were diagnosed with simple steatosis and not overt NASH. They also showed reduced expression of lipogenic and lipid-uptake markers and less signs of inflammation in the liver. GRK2± mice preserved hepatic protective mechanisms as enhanced autophagy and mitochondrial fusion and biogenesis, together with reduced endoplasmic reticulum stress. GRK2 protein was increased in MCD-fed WT but not in GRK2± mice, and enhanced GRK2 expression potentiated palmitic acid-triggered lipid accumulation in human hepatocytes directly relating GRK2 levels to steatosis. GRK2 protein and mRNA levels were increased in human liver biopsies from simple steatosis or NASH patients in two different human cohorts. Our results describe a functional relationship between GRK2 levels and hepatic lipid accumulation and implicate GRK2 in the establishment and/or development of NASH.

Treatment of NASH with Gastric Bypass

PURPOSE OF REVIEW

Nonalcoholic steatohepatitis (NASH) is a spectrum of nonalcoholic fatty liver disease (NAFLD). It is defined as the presence of fatty liver along with inflammation and hepatocyte injury. To date, weight loss achieved via lifestyle intervention remains the mainstay of NASH treatment. However, given the known benefit of weight loss on NASH and the known effect of bariatric surgery on weight loss, several studies have explored the potential role of bariatric surgery on the treatment of NASH.

RECENT FINDINGS

This review article summarizes the evidence on the effect of Roux-en-Y gastric bypass (RYGB), a common bariatric surgery, on NASH therapy. Specifically, studies show that RYGB is associated with an improvement of all NASH histologic features at 1 year. Compared to adjustable gastric band, RYGB appears to be superior at treating NASH. Randomized controlled trials and long-term studies are underway to better clarify the role of these procedures specifically for NASH therapy.

Biomarkers for hepatocellular carcinoma: What’s new on the horizon?

Treatment of advanced hepatocellular carcinoma remains unsatisfying and so far only prognostic biomarkers like α-fetoprotein have been established. No clear predictive biomarker is currently available for standard of care therapies, including targeted therapies like sorafenib. Novel therapeutic options like immune checkpoint inhibitors may pose new challenges to identification and validation of such markers. Currently, PD-L1 expression via immunohistochemistry and tumor mutational burden via next-generation sequencing are explored as predictive biomarkers for these novel treatments. Limited tissue availability due to lack of biopsies still restricts the use of tissue based approaches. Novel methods exploring circulating or cell free nucleic acids (DNA, RNA or miRNA-containing exosomes) could provide a new opportunity to establish predictive biomarkers. Epigenetic profiling and next-generation sequencing approaches from liquid biopsies are under development. Sample size, etiologic and geographical background need to be carefully addressed in such studies to achieve meaningful results that could be translated into clinical practice. Proteomics, metabolomics and molecular imaging are further emerging technologies.

Cell-Free Circulating Nucleic Acids as Early Biomarkers for NAFLD and NAFLD-Associated Disorders

Non-alcoholic fatty liver disease (NAFLD) is the worldwide most common cause of chronic liver pathology, which prevalence strongly correlates with the increasing incidence of diabetes, obesity and metabolic syndrome in the general population. Simple steatosis, the earliest NAFLD stage, usually remains asymptomatic, and appropriate changes in the lifestyle, as well as the diet, can reverse the affected liver into the healthy state. The potential of simple steatosis to progress into severe fibrotic stages and to facilitate carcinogenesis necessitates timely NAFLD detection and risk stratification in community-based healthcare settings. Since their initial discovery a decade ago, extracellular circulating miRNAs have been found in all human biological fluids including blood and shown to hold great promises as non-invasive biomarkers. Normally, intracellular miRNAs participate in the regulation of gene expression, but once released by dying/dead cells they remain highly stable in the extracellular environment for prolonged periods. Therefore, circulating miRNA profiles can reflect the ongoing pathogenic processes in body's tissues and organs, and enable highly sensitive non-invasive diagnosis of multiple disorders. A non-urgent character of the NAFLD-related decision-making justifies the use of chronic liver diseases as an excellent test case for examining the practical utility of circulating miRNAs as biomarkers for longitudinal monitoring of human health. In this review, we summarize the state-of-the-art in the field of early diagnosis of NAFLD using circulating blood miRNAs, and stress the necessity of additional experimental validation of their diagnostic potential. We further emphasize on the potential diagnostics promises of other cell-free RNA species found in human biological fluids.

Non-Alcoholic Fatty Liver Disease in Overweight Children: Role of Fructose Intake and Dietary Pattern

The role of nutrition and diet in the development of non-alcoholic fatty liver disease (NAFLD) is still not fully understood. In the present study, we determined if dietary pattern and markers of intestinal permeability differ between overweight children with and without NAFLD. In addition, in a feasibility study, we assessed the effect of a moderate dietary intervention only focusing on nutrients identified to differ between groups on markers of intestinal barrier function and health status. Anthropometric data, dietary intake, metabolic parameters, and markers of inflammation, as well as of intestinal permeability, were assessed in overweight children (n = 89, aged 5⁻9) and normal-weight healthy controls (n = 36, aged 5⁻9). Sixteen children suffered from early signs of NAFLD, e.g., steatosis grade 1 as determined by ultrasound. Twelve children showing early signs of NAFLD were enrolled in the intervention study (n = 6 intervention, n = 6 control). Body mass index (BMI), BMI standard deviation score (BMI-SDS), and waist circumference were significantly higher in NAFLD children than in overweight children without NAFLD. Levels of bacterial endotoxin, lipopolysaccharide-binding protein (LBP), and proinflammatory markers like interleukin 6 (IL-6) and tumor necrosis factor α (TNFα) were also significantly higher in overweight children with NAFLD compared to those without. Total energy and carbohydrate intake were higher in NAFLD children than in those without. The higher carbohydrate intake mainly resulted from a higher total fructose and glucose intake derived from a significantly higher consumption of sugar-sweetened beverages. When counseling children with NAFLD regarding fructose intake (four times, 30⁻60 min within 1 year; one one-on-one counseling and three group counselings), neither alanine aminotransferase (ALT) nor aspartate aminotransferase (AST) activity in serum changed; however, diastolic blood pressure (p < 0.05) and bacterial endotoxin levels (p = 0.06) decreased markedly in the intervention group after one year. Similar changes were not found in uncounseled children. Our results suggest that a sugar-rich diet might contribute to the development of early stages of NAFLD in overweight children, and that moderate dietary counseling might improve the metabolic status of overweight children with NAFLD.

DNA methylation biomarkers for hepatocellular carcinoma

Background

Aberrant methylation of DNA is a key driver of hepatocellular carcinoma (HCC). In this study, we sought to integrate four cohorts profile datasets to identify such abnormally methylated genes and pathways associated with HCC.

Methods

To this end, we downloaded microarray datasets examining gene expression (GSE84402, GSE46408) and gene methylation (GSE73003, GSE57956) from the GEO database. Abnormally methylated differentially expressed genes (DEGs) were sorted and pathways were analyzed. The String database was then used to perform enrichment and functional analysis of identified pathways and genes. Cytoscape software was used to create a protein-protein interaction network, and MCODE was used for module analysis. Finally, overall survival analysis of hub genes was performed by the OncoLnc online tool.

Results

In total, we identified 19 hypomethylated highly expressed genes and 14 hypermethylated lowly expressed genes at the screening step, and finally found six mostly changed hub genes including MAD2L1, CDC20, CCNB1, CCND1, AR and ESR1. Pathway analysis showed that aberrantly methylated-DEGs mainly associated with the cell cycle process, p53 signaling, and MAPK signaling in HCC. After validation in TCGA database, the methylation and expression status of hub genes was significantly altered and same with our results. Patients with high expression of MAD2L1, CDC20 and CCNB1 and low expression of CCND1, AR, and ESR1 was associated with shorter overall survival.

Conclusions

Taken together, we have identified novel aberrantly methylated genes and pathways linked to HCC, potentially offering novel insights into the molecular mechanisms governing HCC progression and serving as novel biomarkers for precision diagnosis and disease treatment.

Dissociation of Fatty Liver and Insulin Resistance in I148M PNPLA3 Carriers: Differences in Diacylglycerol (DAG) FA18:1 Lipid Species as a Possible Explanation

Fatty liver is tightly associated with insulin resistance and the development of type 2 diabetes. I148M variant in patatin-like phospholipase domain-containing protein 3 (PNPLA3) gene is associated with high liver fat but normal insulin sensitivity. The underlying mechanism of the disassociation between high liver fat but normal insulin sensitivity remains obscure. We investigated the effect of I148M variant on hepatic lipidome of subjects with or without fatty liver, using the Lipidyzer method. Liver samples of four groups of subjects consisting of normal liver fat with wild-type PNPLA3 allele (group 1); normal liver fat with variant PNPLA3 allele (group 2); high liver fat with wild-type PNPLA3 allele (group 3); high liver fat with variant PNPLA3 allele (group 4); were analyzed. When high liver fat to normal liver fat groups were compared, wild-type carriers (group 3 vs. group 1) showed similar lipid changes compared to I148M PNPLA3 carriers (group 4 vs. group 2). On the other hand, in wild-type carriers, increased liver fat significantly elevated the proportion of specific DAGs (diacylglycerols), mostly DAG (FA18:1) which, however, remained unchanged in I148M PNPLA3 carriers. Since DAG (FA18:1) has been implicated in hepatic insulin resistance, the unaltered proportion of DAG (FA18:1) in I148M PNPLA3 carriers with fatty liver may explain the normal insulin sensitivity in these subjects.

Generic chemoprevention of hepatocellular carcinoma

Chronic fibrotic liver disease caused by viral or metabolic etiologies is a high-risk condition for developing hepatocellular carcinoma (HCC). Even after curative treatment of early-stage HCC tumor, the carcinogenic microenvironment persists in the remnant diseased liver and supports the development of de novo HCC tumors (de novo HCC recurrence). Therefore, prevention of HCC development in patients at risk of not only first-primary but also second-primary HCC tumors is theoretically the most impactful strategy to improve patient prognosis. However, no such therapy has been established to date. One major challenge is the identification of clinically relevant targets that can be achieved by utilizing the reverse-engineering strategy of chemoprevention discovery, which integrates omics information from clinical cohorts with completed follow-up for cancer development. Clinical and experimental studies have suggested etiology-specific and generic candidate HCC chemoprevention strategies, including statins, antidiabetic drugs, selective molecular targeted agents, and dietary and nutritional substances. Clinical testing of the candidate compounds can be cost-effectively performed by combining it with HCC risk biomarker evaluation to specify the target patient population most likely to benefit from the therapy. Nontoxic, generic agents will have broad clinical applicability across the diverse HCC etiologies and clinical contexts and are expected to substantially improve the still dismal prognosis of HCC.

Liver fibrosis: Pathophysiology, pathogenetic targets and clinical issues

The progression of chronic liver diseases (CLD), irrespective of etiology, involves chronic parenchymal injury, persistent activation of inflammatory response as well as sustained activation of liver fibrogenesis and wound healing response. Liver fibrogenesis, is a dynamic, highly integrated molecular, cellular and tissue process responsible for driving the excess accumulation of extracellular matrix (ECM) components (i.e., liver fibrosis) sustained by an eterogeneous population of hepatic myofibroblasts (MFs). The process of liver fibrogenesis recognizes a number of common and etiology-independent mechanisms and events but it is also significantly influenced by the specific etiology, as also reflected by peculiar morphological patterns of liver fibrosis development. In this review we will analyze the most relevant established and/or emerging pathophysiological issues underlying CLD progression with a focus on the role of critical hepatic cell populations, mechanisms and signaling pathways involved, as they represent potential therapeutic targets, to finally analyze selected and relevant clinical issues.

Targeting a phospho-STAT3-miRNAs pathway improves vesicular hepatic steatosis in an in vitro and in vivo model

Non-alcoholic fatty liver disease (NAFLD) is a leading cause of chronic liver disease. Although genetic predisposition and epigenetic factors contribute to the development of NAFLD, our understanding of the molecular mechanism involved in the pathogenesis of the disease is still emerging. Here we investigated a possible role of a microRNAs-STAT3 pathway in the induction of hepatic steatosis. Differentiated HepaRG cells treated with the fatty acid sodium oleate (fatty dHepaRG) recapitulated features of liver vesicular steatosis and activated a cell-autonomous inflammatory response, inducing STAT3-Tyrosine-phosphorylation. With a genome-wide approach (Chromatin Immunoprecipitation Sequencing), many phospho-STAT3 binding sites were identified in fatty dHepaRG cells and several STAT3 and/or NAFLD-regulated microRNAs showed increased expression levels, including miR-21. Innovative CARS (Coherent Anti-Stokes Raman Scattering) microscopy revealed that chemical inhibition of STAT3 activity decreased lipid accumulation and deregulated STAT3-responsive microRNAs, including miR-21, in lipid overloaded dHepaRG cells. We were able to show in vivo that reducing phospho-STAT3-miR-21 levels in C57/BL6 mice liver, by long-term treatment with metformin, protected mice from aging-dependent hepatic vesicular steatosis. Our results identified a microRNAs-phosphoSTAT3 pathway involved in the development of hepatic steatosis, which may represent a molecular marker for both diagnosis and therapeutic targeting.

Multicentre study of the prognostic impact of preoperative bodyweight on long-term prognosis of hepatocellular carcinoma

BACKGROUND

Whether preoperative bodyweight is associated with long-term prognosis in patients after liver resection for hepatocellular carcinoma (HCC) is controversial. This study aimed to investigate the relationship of patient weight with long-term recurrence and overall survival (OS) after curative liver resection for HCC.

METHODS

Data for patients with HCC who underwent curative liver resection between 2000 and 2015 in five centres in China were analysed retrospectively in three groups according to their preoperative BMI: underweight (BMI 18·4 kg/m² or less), normal weight (BMI 18·5-24·9 kg/m² ) and overweight (BMI 25·0 kg/m² or above). Patients' baseline characteristics, operative variables and long-term survival outcomes were compared. Univariable and multivariable Cox regression analyses were performed to identify risk factors for OS and recurrence-free survival (RFS) after resection.

RESULTS

Of 1524 patients, 107 (7·0 per cent) were underweight, 891 (58·5 per cent) were of normal weight and 526 (34·5 per cent) were overweight. Univariable analyses showed that underweight and overweight patients had poorer OS (both P < 0·001) and RFS (both P < 0·001) than patients of normal weight. Multivariable Cox regression analysis also identified both underweight and overweight to be independent risk factors for OS (hazard ratio (HR) 1·22, 95 per cent c.i. 1·19 to 1·56, P = 0·019; and HR 1·57, 1·36 to 1·81, P < 0·001, respectively) and RFS (HR 1·28, 1·16 to 1·53, P = 0·028; and HR 1·34, 1·17 to 1·54, P < 0·001).

CONCLUSION

Underweight and overweight patients appear to have a worse prognosis than those of normal weight following liver resection for HCC.

High-fat diet consumption reduces hepatic folate transporter expression via nuclear respiratory factor-1

Folate is an essential micronutrient for biological function. The liver, a primary organ for folate metabolism and storage, plays an important role in folate homeostasis. Proton-coupled folate transporter (PCFT) and reduced folate carrier (RFC) are the major folate transporters responsible for folate uptake at basolateral membrane of hepatocytes. Low serum folate levels are frequently associated with obesity. We investigated the mechanism that regulated folate status in a mouse model with diet-induced obesity. Mice (C57BL/6J) were fed a high-fat diet (60% kcal fat) for 8 weeks. Mice displayed increased hepatic lipid accumulation and decreased folate levels in the liver and serum compared to mice fed a normal chow diet (10% kcal fat). High-fat diet-fed mice had low expression of PCFT and RFC and decreased nuclear respiratory factor-1 (NRF-1)/DNA-binding activity. Treatment with NRF-1 siRNA or palmitic acid reduced folate transporter expression in hepatocytes. Inhibition of NRF-1 mediated folate transporter expression significantly reduced intracellular folate levels. These results suggest that chronic consumption of high-fat diets impairs folate transporter expression via NRF-1-dependent mechanism, leading to reduced hepatic folate storage. Understanding the regulation of folate homeostasis in obesity may have an important implication in current guideline of folate intake. KEY MESSAGES: Serum and liver folate levels are decreased in diet-induced obese mice. Chronic high-fat diet consumption impairs expression of hepatic PCFT and RFC. NRF-1 regulates hepatic folate transporters expression and folate levels.

Mouse models of hepatocellular carcinoma: an overview and highlights for immunotherapy research

Mouse models are the basis of preclinical and translational research in hepatocellular carcinoma (HCC). Multiple methods exist to induce tumour formation in mice, including genetically engineered mouse models, chemotoxic agents, intrahepatic or intrasplenic injection of tumour cells and xenograft approaches. Additionally, as HCC generally develops in the context of diseased liver, methods exist to induce liver disease in mice to mimic viral hepatitis, fatty liver disease, fibrosis, alcohol-induced liver disease and cholestasis. Similar to HCC in humans, response to therapy in mouse models is monitored with imaging modalities such as CT or MRI, as well as additional techniques involving bioluminescence. As immunotherapy is increasingly applied to HCC, mouse models for these approaches are required for preclinical data. In studying cancer immunotherapy, it is important to consider aspects of antitumour immune responses and to produce a model that mimics the complexity of the immune system. This Review provides an overview of the different mouse models of HCC, presenting techniques to prepare an HCC mouse model and discussing different approaches to help researchers choose an appropriate model for a specific hypothesis. Specific aspects of immunotherapy research in HCC and the applied mouse models in this field are also highlighted.

The Role of Long Non-Coding RNAs (lncRNAs) in the Development and Progression of Fibrosis Associated with Nonalcoholic Fatty Liver Disease (NAFLD)

Nonalcoholic fatty liver disease (NAFLD) encompasses a spectrum of conditions ranging from hepatic steatosis to inflammation (nonalcoholic steatohepatitis or NASH) with or without fibrosis, in the absence of significant alcohol consumption. The presence of fibrosis in NASH patients is associated with greater liver-related morbidity and mortality; however, the molecular mechanisms underlying the development of fibrosis and cirrhosis in NAFLD patients remain poorly understood. Long non-coding RNAs (lncRNAs) are emerging as key contributors to biological processes that are underpinning the initiation and progression of NAFLD fibrosis. This review summarizes the experimental findings that have been obtained to date in animal models of liver fibrosis and NAFLD patients with fibrosis. We also discuss the potential applicability of circulating lncRNAs to serve as biomarkers for the diagnosis and prognosis of NAFLD fibrosis. A better understanding of the role played by lncRNAs in NAFLD fibrosis is critical for the identification of novel therapeutic targets for drug development and improved, noninvasive methods for disease diagnosis.