Liver fibrosis markers of nonalcoholic steatohepatitis

Serologic Biomarkers for Hepatic Fibrosis in Obese Children with Nonalcoholic Steatohepatitis

Purpose

The prevalence of nonalcoholic steatohepatitis (NASH) is increasing with the increasing prevalence of childhood obesity. Although NASH has a high risk of progression to liver fibrosis and cirrhosis, few studies have reported noninvasive markers for predicting hepatic fibrosis in children. This study aimed to evaluate and compare the diagnostic accuracies of serologic biomarkers and scoring systems for hepatic fibrosis in obese children with NASH.

Methods

A total of 96 children were diagnosed with NASH based on liver biopsy findings and divided into two groups according to the degree of liver fibrosis: mild (stage 0-1) or advanced (stage 2-4). Clinical and laboratory parameters and serum levels of hyaluronic acid and type IV collagen were measured. The aspartate aminotransferase/platelet ratio index (APRI) and fibrosis-4 (FIB-4) score were calculated.

Results

Among the noninvasive markers, only serum type IV collagen level and FIB-4 were significantly different between the two groups. The area under the receiver operating curve of each biomarker and scoring system was 0.80 (95% confidence interval [CI]: 0.70-0.90) for type IV collagen at an optimal cutoff of 148 ng/mL (sensitivity 69.8%, specificity 84.6%), followed by 0.69 (95% CI: 0.57-0.83) for APRI, 0.68 (95% CI: 0.56-0.80) for FIB-4, and 0.65 (95% CI: 0.53-0.77) for hyaluronic acid.

Conclusion

Type IV collagen as a single noninvasive serologic biomarker for hepatic fibrosis and FIB-4 as a hepatic fibrosis score are beneficial in predicting advanced hepatic fibrosis and determining proper diagnosis and treatment strategies before fibrosis progresses in obese children with NASH.

The Association between Diet-Exercise Patterns and Cirrhosis: A Cross-Sectional Study from NHANES 2017-March 2020

BACKGROUND

Liver cirrhosis (LC) is one of the most significant causes of morbidity and mortality in patients with chronic liver disease worldwide. Nutrition may be an important component of primary prevention of chronic liver disease. Diet-exercise patterns frame the eating behaviors and exercise habits of people through statistical methods related to nutritional epidemiology, which can explore the relationship between living habits and diseases among diverse populations. The purpose of this study was to explore the association between diet-exercise patterns and cirrhosis, and provide guidance on preventive diets for liver patients.

METHODS

This study identified diet-exercise patterns via clustering analysis of principal components and assessed their association with cirrhosis through the population samples of the National Health and Nutrition Examination Survey (NHANES) from 2017 to March 2020.

RESULTS

We identified two diet-exercise patterns that were named the "prudent pattern" (consumption of various staple foods, eggs, meat, fruits and vegetables; less sedentary) and the "dangerous pattern" (higher consumption of desserts, nuts, milk, meat, alcoholic beverages; recreational activities). The t-test demonstrated a significant relationship between patterns and multiple foods. The simple logistic regression test showed a lower risk of cirrhosis in those in the "prudent pattern" (OR = 0.73, 95%CI = 0.59-0.93).

CONCLUSIONS

Two diet-exercise patterns associated with cirrhosis were identified: "prudent pattern" and "dangerous pattern". The results of this study may be useful for suggesting preventive diets for people at risk of cirrhosis.

Vinpocetine represses the progression of nonalcoholic steatohepatitis in mice by mediating inflammasome components via NF-κB signaling

BACKGROUND

Inflammasome activation is known to be involved in nonalcoholic steatohepatitis (NASH). Vinpocetine is a derivative of vincamine and is reported to suppress the activation of inflammasome.

METHODS

This study explored the therapeutical potential of Vinpocetine on NASH. Mice were fed with a choline-deficient (MCD) or chow diet in the presence or absence of Vinpocetine for 8 weeks. H&E staining and biochemical assays were determined to evaluate the hepatic steatosis and fibrosis symptoms. In addition, primary hepatocytes and Kupffer cells were isolated and induced by MCD or lipopolysaccharides/cholesterol crystals with or without Vinpocetine. ELISAs, qPCR, and Western blotting were applied to determine the levels of NASH-related biomarkers in both in vivo mouse model and in vitro cell models.

RESULTS

Treatment of Vinpocetine did not cause observable side effects against and MCD-induced cells and mouse NASH model. However, treatment of Vinpocetine ameliorated hepatic steatosis and fibrosis and suppressed the levels of alanine transaminase and aspartate transferase in the mouse NASH model. In addition, treatment of Vinpocetine suppressed the mRNA and protein levels of inflammasome components both in vitro and in vivo.

CONCLUSION

Vinpocetine suppressed NASH in mice by mediating inflammasome components via nuclear factor κB signaling.

Gypenoside XIII regulates lipid metabolism in HepG2 hepatocytes and ameliorates nonalcoholic steatohepatitis in mice

Gypenoside XIII is isolated from Gynostemma pentaphyllum (Thunb.) Makino. In mice, G. pentaphyllum extract and gypenoside LXXV have been shown to improve non-alcoholic steatohepatitis (NASH). This study investigated whether gypenoside XIII can regulate lipid accumulation in fatty liver cells or attenuate NASH in mice. We used HepG2 hepatocytes to establish a fatty liver cell model using 0.5 mM oleic acid. Fatty liver cells were treated with different concentrations of gypenoside XIII to evaluate the molecular mechanisms of lipid metabolism. In addition, a methionine/choline-deficient diet induced NASH in C57BL/6 mice, which were given 10 mg/kg gypenoside XIII by intraperitoneal injection. In fatty liver cells, gypenoside XIII effectively suppressed lipid accumulation and lipid peroxidation. Furthermore, gypenoside XIII significantly increased SIRT1 and AMPK phosphorylation to decrease acetyl-CoA carboxylase phosphorylation, reducing fatty acid synthesis activity. Gypenoside XIII also decreased lipogenesis by suppressing sterol regulatory element-binding protein 1c and fatty acid synthase production. Gypenoside XIII also increased lipolysis and fatty acid β-oxidation by promoting adipose triglyceride lipase and carnitine palmitoyltransferase 1, respectively. In an animal model of NASH, gypenoside XIII effectively decreased the lipid vacuole size and number and reduced liver fibrosis and inflammation. These findings suggest that gypenoside XIII can regulate lipid metabolism in fatty liver cells and improve liver fibrosis in NASH mice. Therefore, gypenoside XIII has potential as a novel agent for the treatment of NASH.

Yohimbine ameliorates liver inflammation and fibrosis by regulating oxidative stress and Wnt/β-catenin pathway

BACKGROUND AND PURPOSE

Chronic liver injury, caused by various aetiologies, causes recurrent tissue damage, culminating in decreased liver regenerative ability and resulting in fibrosis followed by cirrhosis. In this study, the anti-fibrotic activity of Yohimbine hydrochloride (YHC) was investigated using various in vitro models and in vivo models.

METHODS

To assess the anti-inflammatory, antioxidant, and anti-fibrotic effects of YHC, lipopolysaccharide or TGF-β induced differentiation or lipid-induced oxidative-stress models were employed using HLECs, HSC-LX2, and HepG2 cells. Further, thioacetamide (TAA) induced hepatic inflammation/fibrosis models were utilized to validate the YHC's anti-fibrotic activity in rats.

RESULTS

Inflammation/differentiation experiments in HLECs and HSC-LX2 revealed that YHC treatment significantly (p < 0.001) mitigated the lipopolysaccharide or TGF-β induced upregulation of inflammatory and fibrotic markers expression respectively. In addition, YHC dose-dependently reduced the TGF-β induced migration and palmitic acid-induced oxidative stress in HepG2 cells. Further, TAA administration (5 weeks) in vivo rat model showed increased inflammatory marker levels/expression, oxidative stress, and pathological abnormalities. Additionally, TAA administration (9 weeks) elevated the fibrotic marker expression, collagen deposition in liver tissues, and shortened longevity in rats. Treatment with YHC dose-dependently mitigated the TAA-induced abnormalities in both inflammation and fibrosis models and improved the survival of the rats. Further mechanistic approaches revealed that TAA administration elevated the JNK, Wnt components and β-catenin expression in hepatic stellate cells and animal tissues. Further treatment with YHC significantly modulated the JNK/Wnt/β-catenin signaling. Moreover, the β-catenin nuclear translocation results showed that β-catenin levels were significantly elevated in the nuclear fraction of TAA control samples and reduced in YHC-treated samples.

CONCLUSION

Yohimbine treatment significantly improved inflammation and fibrosis by inhibiting differentiation, oxidative stress, and collagen deposition by partly modulating the JNK/Wnt/β-catenin pathway. These results might serve as a foundation for proposing yohimbine as a potential lead compound for liver fibrosis.

Investigation of Serum Markers of Hepatic Fibrosis in Equids

Liver disease is common in equine practice, and treatment and prognosis are dependent on histopathologic examination of biopsies. Liver biopsy is invasive and expensive which restricts its use. Serum markers are used to predict hepatic fibrosis in humans. This study aimed to investigate the enhanced liver fibrosis (ELF) test, based on serum Hyaluronic Acid (HA), procollagen III N-terminal peptide (PIIINP), and tissue inhibitor of metalloproteinase 1 (TIMP-1) to detect hepatic fibrosis in equids. Four groups were included; two with increased serum concentrations of liver-derived enzymes and a liver biopsy (group H; 10 horses and ponies and group D; 10 donkeys) and two without any evidence of liver disease (group HC; 10 horses and ponies and group DC; 10 donkeys). All samples were analyzed for concentrations of HA, PIINP, and TIMP-1. Given the failure to detect TIMP-1 in most subjects, a novel eELF (equid ELF) score was calculated, based on HA and PIIINP. HA and PIIINP concentrations and the eELF score, were compared with determined hepatic fibrosis. HA, PIIINP, and eELF were significantly greater in horses and ponies with a histopathologic fibrosis score ≥ 2 compared with those < 2. A similar observation was found with donkeys for HA and eELF. A significant correlation was found between fibrosis score and HA, PIIINP, and eELF for horses and ponies, and between fibrosis score and HA and eELF in donkeys. Serum HA and the eELF score might be useful serum markers to predict and monitor hepatic fibrosis in horses, ponies, and donkeys.

AN1284 attenuates steatosis, lipogenesis, and fibrosis in mice with pre-existing non-alcoholic steatohepatitis and directly affects aryl hydrocarbon receptor in a hepatic cell line

Non-alcoholic steatohepatitis (NASH) is an aggressive form of fatty liver disease with hepatic inflammation and fibrosis for which there is currently no drug treatment. This study determined whether an indoline derivative, AN1284, which significantly reduced damage in a model of acute liver disease, can reverse steatosis and fibrosis in mice with pre-existing NASH and explore its mechanism of action. The mouse model of dietary-induced NASH reproduces most of the liver pathology seen in human subjects. This was confirmed by RNA-sequencing analysis. The Western diet, given for 4 months, caused steatosis, inflammation, and liver fibrosis. AN1284 (1 mg or 5 mg/kg/day) was administered for the last 2 months of the diet by micro-osmotic-pumps (mps). Both doses significantly decreased hepatic damage, liver weight, hepatic fat content, triglyceride, serum alanine transaminase, and fibrosis. AN1284 (1 mg/kg/day) given by mps or in the drinking fluid significantly reduced fibrosis produced by carbon tetrachloride injections. In human HUH7 hepatoma cells incubated with palmitic acid, AN1284 (2.1 and 6.3 ng/ml), concentrations compatible with those in the liver of mice treated with AN1284, decreased lipid formation by causing nuclear translocation of the aryl hydrocarbon receptor (AhR). AN1284 downregulated fatty acid synthase (FASN) and sterol regulatory element-binding protein 1c (SREBP-1c) and upregulated Acyl-CoA Oxidase 1 and Cytochrome P450-a1, genes involved in lipid metabolism. In conclusion, chronic treatment with AN1284 (1mg/kg/day) reduced pre-existing steatosis and fibrosis through AhR, which affects several contributors to the development of fatty liver disease. Additional pathways are also influenced by AN1284 treatment.

Emricasan for the treatment of liver cirrhosis: a meta-analysis of randomized controlled trials

Introduction

The efficacy of emricasan for liver cirrhosis remains controversial. We conduct a systematic review and meta-analysis to explore the influence of emricasan versus placebo on the treatment of liver cirrhosis.

Methods

We have searched PubMed, EMbase, Web of science, EBSCO, and Cochrane library databases through August 2021 and included randomized controlled trials (RCTs) assessing the efficacy of emricasan versus placebo for liver cirrhosis. This meta-analysis was performed using the random-effect model.

Results

Four RCTs were included in the meta-analysis. Overall, compared with control group for liver cirrhosis, emricasan treatment had no substantial impact on MELD (SMD=-0.19; 95% CI=-0.44 to 0.06; P=0.14), INR (SMD=0.12; 95% CI=-0.13 to 0.37; P=0.36), total bilirubin (SMD=-0.27; 95% CI=-0.56 to 0.01; P=0.06), serum albumin (SMD=0; 95% CI=-0.25 to 0.25; P=1.00) or adverse events (OR=1.35; 95% CI=0.56 to 3.24; P=0.50).

Conclusions

Emricasan treatment provided no benefit for the treatment of liver cirrhosis.

Potential Hepatic Lipid Markers Associated with Nonalcoholic Steatohepatitis and Fibrosis in Morbid Obesity Patients

This study investigated differences in lipidomic profile features in nonalcoholic steatohepatitis (NASH) between mild and significant liver fibrosis cases among patients with morbid obesity. Wedge liver biopsy was performed during sleeve gastrectomy and significant liver fibrosis was defined as a fibrosis score ≥ 2. We selected patients with NASH with non/mild fibrosis (stage F0-F1; n = 30) and NASH with significant fibrosis (stage F2-F4; n = 30). The results of the liver tissue lipidomic analysis revealed that the fold changes of triglyceride (TG) (52:6); cholesterol ester (CE) (20:1); phosphatidylcholine (PC) (38:0) and (50:8); phosphatidic acid (PA) (40:4); phosphatidylinositol (PI) (49:4); phosphatidylglycerol (PG) (40:2); and sphingomyelin (SM) (35:0) and (37:0) were significantly lower in patients with NASH with F2-F4 than those with NASH with F0-F1 (p < 0.05). However, the fold changes of PC (42:4) were relatively higher in patients with NASH with stage 2-4 fibrosis (p < 0.05). Moreover, predictive models incorporating serum markers levels, ultrasonographic studies, and levels of specific lipid components [PC (42:4) and PG (40:2)] yielded the highest area under receiver operating curve (0.941), suggesting a potential correlation between NASH fibrosis stages and liver lipid accumulation among specific lipid species subclasses. This study demonstrated that the concentrations of particular lipid species in the liver correlate with NASH fibrosis stages and may indicate hepatic steatosis regression or progression in patients with morbid obesity.

Machine learning models are superior to noninvasive tests in identifying clinically significant stages of NAFLD and NAFLD-related cirrhosis

BACKGROUND AND AIMS

We assessed the performance of machine learning (ML) models in identifying clinically significant NAFLD-associated liver fibrosis and cirrhosis.

APPROACH AND RESULTS

We implemented ML models including logistic regression (LR), random forest (RF), and artificial neural network to predict histological stages of fibrosis using 17 demographic/clinical features in 1370 patients with NAFLD who underwent liver biopsy, FibroScan, and labs within a 6-month period at multiple U.S. centers. Histological stages of fibrosis (≥F2, ≥F3, and F4) were predicted using ML, FibroScan liver stiffness measurements, and Fibrosis-4 index (FIB-4). NASH with significant fibrosis (NAS ≥ 4 + ≥F2) was assessed using ML, FibroScan-AST (FAST) score, FIB-4, and NAFLD fibrosis score (NFS). We used 80% of the cohort to train and 20% to test the ML models. For ≥F2, ≥F3, F4, and NASH + NAS ≥ 4 + ≥F2, all ML models, especially RF, had primarily higher accuracy and AUC compared with FibroScan, FIB-4, FAST, and NFS. AUC for RF versus FibroScan and FIB-4 for ≥F2, ≥F3, and F4 were (0.86 vs. 0.81, 0.78), (0.89 vs. 0.83, 0.82), and (0.89 vs. 0.86, 0.85), respectively. AUC for RF versus FAST, FIB-4, and NFS for NASH + NAS ≥ 4 + ≥F2 were (0.80 vs. 0.77, 0.66, 0.63). For NASH + NAS ≥ 4 + ≥F2, all ML models had lower/similar percentages within the indeterminate zone compared with FIB-4 and NFS. Overall, ML models performed better in sensitivity, specificity, positive predictive value, and negative predictive value compared with traditional noninvasive tests.

CONCLUSIONS

ML models performed better overall than FibroScan, FIB-4, FAST, and NFS. ML could be an effective tool for identifying clinically significant liver fibrosis and cirrhosis in patients with NAFLD.

Fibrosis-4 index, a predictor for prognosis of hepatocellular carcinoma patients after curative hepatectomy even in hepatitis B virus dominant populations

Purpose

Liver fibrosis plays an important role in the development of hepatocellular carcinoma (HCC) and determining its prognosis. Although many staging systems and liver reserve models have been developed without the intention of predicting prognosis of HCC, some studies have investigated their prognostic values in HCC after curative liver resection (LR). The aim of this study is to evaluate prognostic value of non-invasive biomarkers after curative LR.

Methods

Between 2006 and 2013, HCC patients underwent LR were included and total 962 patients were enrolled. All non-invasive biomarkers (fibrosis 4 index (FIB-4), aspartate aminotransferase-to-platelet ratio index (APRI), aspartate aminotransferase-to-alanine aminotransferase ratio (AAR), AAR-to-platelet ratio index (AARPRI), and albumin-bilirubin (ALBI) score) were measured at the time of HCC diagnosis. To binarize each biomarker, an optimal cut-off value for fibrosis stage was selected using the value of minimum distance from the left-upper corner of the receiver operating characteristic curve with a specificity >60%. We performed Cox regression analysis on 2-year recurrence-free survival (RFS) and overall survival (OS).

Results

The area under curve values for FIB-4 and APRI were the largest for fibrosis stage compared to other biomarkers, 0.669 (95% confidential interval (CI), 0.610-0.719) and 0.748 (95% CI, 0.692-0.800), respectively. Between those two indices, FIB-4 is considered a statistically significant prognostic factor of RFS in HCC patients after LR. The HR for 2-year RFS and OS were 1.81 (95% CI, 1.18-2.77; P = 0.007) and 2.36 (95% CI, 0.99-5.65; P = 0.054), respectively.

Conclusion

FIB-4 is identified as a statistically significant predictor of HCC prognosis after curative LR even in HBV dominant populations.

Coinfection of Clonorchis sinensis and hepatitis B virus: clinical liver indices and interaction in hepatic cell models

BACKGROUND

In China, people infected with hepatitis B virus (HBV) are commonly found in areas with a high prevalence of Clonorchis sinensis, a trematode worm. Published studies have reported that the progression of hepatitis B is affected by coinfection C. sinensis.

METHODS

Clinical data from a total of 72 patients with C. sinensis and HBV (as sole infection or with coinfections) and 29 healthy individuals were analysed. We also incubated the hepatic stellate cell line LX-2 with total proteins from C. sinensis adult worms (CsTPs) and HBV-positive sera. In addition, the human hepatoblastoma cell line HepG2.2.15 was treated with the antiviral drug entecavir (ETV), CsTPs and the anti-C. sinensis drug praziquantel (PZQ).

RESULTS

Our clinical data indicated that the levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), total bilirubin (TB) and hyaluronic acid (HA) were significantly higher in patients with coinfection than in those infected with HBV only. In cell models, compared with the model in which LX-2 cells were incubated with HBV-positive sera (HBV group), transcripts of alpha-smooth muscle actin and types I and III collagen were significantly elevated in the models of LX-2 cells treated with CsTPs and HBV-positive sera (CsTP+HBV group), while the messenger RNA levels of tumour necrosis factor-α, interleukin (IL)-1β and IL-6 in the CsTP+HBV group were clearly lower. The HBV surface antigen and hepatitis B e-antigen levels were higher in the HepG2.2.15 cells treated with ETV and CsTPs than in those in the ETV group and in the cells administered a mixture of ETV, CsTPs and PZQ.

CONCLUSIONS

These results confirmed that C. sinensis and HBV coinfection could aggravate the progression of liver fibrosis. CsTPs might promote chronic inflammation of the liver in individuals with HBV infection, resulting in the development of hepatic fibrosis.

The p-STAT3/ANXA2 axis promotes caspase-1-mediated hepatocyte pyroptosis in non-alcoholic steatohepatitis

BACKGROUND

To explore the roles of Annexin A2 (ANXA2) on hepatocyte pyroptosis and hepatic fibrosis in nonalcoholic steatohepatitis (NASH) and underlying molecular mechanism.

METHODS

Bioinformatics analyses were performed on transcriptome data of liver tissues from mice and patients with liver fibrosis for screening the hepatocyte pyroptosis-related differential genes. The in vivo NASH mouse model and in vitro NASH cellular model were established. The expression levels of Anxa2/ANXA2 were quantified. Then, the upstream transcription factor of Anxa2 was screened by ChIP-Seq and experimentally verified. The effects of the p-STAT3/ANXA2 axis on Caspase-1 mediated pyroptosis and fibrosis were explored by in vivo and in vitro experiments.

RESULTS

Bioinformatics analyses suggested that the expression of Anxa2/ANXA2 was significantly up-regulated in liver tissues of both NASH mice and patients scoring with high pyroptotic activity. Experimental data showed that the ANXA2 expression was positively associated with the development of hepatocyte pyroptosis and fibrosis. As a transcription factor of ANXA2, p-STAT3 can bind to the promoter of Anxa2 and promote its transcription. The inhibition of p-STAT3 can significantly suppress hepatocyte pyroptosis and fibrosis, which was significantly reversed after the over-expression of Anxa2. Caspase-1 was verified as the player of the p-STAT3/ANXA2 axis to promote pyroptosis and fibrosis. By specifically inhibiting Caspase-1, the promotion effect of the p-STAT3/ANXA2 axis on pyroptosis and fibrosis can be significantly weakened.

CONCLUSION

The p-STAT3 promoted Anxa2 expression at the transcription level, thus activating the Caspase-1 mediated hepatocyte pyroptosis and fibrosis in NASH.

Non-alcoholic fatty liver disease: Is surgery the best current option and can novel endoscopy play a role in the future?

Over the last decade, non-alcoholic fatty liver disease (NAFLD) has overtaken alcohol as the leading cause of cirrhosis in the Western world. There remains to be a licensed pharmacological treatment for NAFLD. Weight loss is advised for all patients with NAFLD. Many patients however, struggle to lose the recommended weight with lifestyle modification alone. Many drugs have either failed to show significant improvement of steatosis or are poorly tolerated. Bariatric surgery has been shown to reduce liver steatosis and regress liver fibrosis. The pathophysiology is not fully understood, however recent evidence has pointed towards changes in the gut microbiome following surgery. Novel endoscopic treatment options provide a minimally invasive alternative for weight loss. Randomised controlled trials are now required for further clarification.

FOSL2 deficiency delays nonalcoholic steatohepatitis progression by regulating LY6D-mediated NLRP3 activation

Lymphocyte antigen 6 family member D (LY6D) was enhanced specifically in senescent cells, while its effects on pyroptosis, a programmed cell death, remains unknown. The goal of this study was to assess the role of LY6D in the mediation of pyroptosis during nonalcoholic steatohepatitis (NASH). After screening out LY6D as a specific liver fibrosis-associated gene using the GSE55747 dataset from the GEO database, we established a NASH mouse model using methionine and choline deficient-diet feeding and an in vitro model using lipopolysaccharide (LPS)-treated hepatocytes. LY6D was overexpressed in NASH livers as well as in LPS-treated hepatocytes. Silencing of LY6D inhibited NASH-associated hepatocyte pyroptosis. With the aid of bioinformatics analysis, promoter-luciferase reporter and ChIP-qPCR assays, we identified FOSL2 as an upstream transcription factor of LY6D. FOSL2, which was highly expressed in NASH, promoted LY6D transcription by binding to the promoter of LY6D. Depletion of FOSL2 significantly inhibited NASH-associated hepatocyte pyroptosis, which was significantly reversed after overexpression of LY6D. Moreover, the promotion of hepatocyte pyroptosis by the FOSL2/LY6D axis was significantly attenuated by specific inhibition of NLRP3. These findings suggesting that FOSL2/LY6D axis may be a key molecular axis and a potential target for NASH therapeutics.

Mechanism and therapeutic strategy of hepatic TM6SF2-deficient non-alcoholic fatty liver diseases via in vivo and in vitro experiments

BACKGROUND

The lack of effective pharmacotherapies for nonalcoholic fatty liver disease (NAFLD) is mainly attributed to insufficient research on its pathogenesis. The pathogenesis of TM6SF2-efficient NAFLD remains unclear, resulting in a lack of therapeutic strategies for TM6SF2-deficient patients.

AIM

To investigate the role of TM6SF2 in fatty acid metabolism in the context of fatty liver and propose possible therapeutic strategies for NAFLD caused by TM6SF2 deficiency.

METHODS

Liver samples collected from both NAFLD mouse models and human participants (80 cases) were used to evaluate the expression of TM6SF2 by using western blotting, immunohistochemistry, and quantitative polymerase chain reaction. RNA-seq data retrieved from the Gene Expression Omnibus database were used to confirm the over-expression of TM6SF2. Knockdown and overexpression of TM6SF2 were performed to clarify the mechanistic basis of hepatic lipid accumulation in NAFLD. MK-4074 administration was used as a therapeutic intervention to evaluate its effect on NAFLD caused by TM6SF2 deficiency.

RESULTS

Hepatic TM6SF2 levels were elevated in patients with NAFLD and NAFLD mouse models. TM6SF2 overexpression can reduce hepatic lipid accumulation, suggesting a protective role for TM6SF2 in a high-fat diet (HFD). Downregulation of TM6SF2, simulating the TM6SF2 E167K mutation condition, increases intracellular lipid deposition due to dysregulated fatty acid metabolism and is characterized by enhanced fatty acid uptake and synthesis, accompanied by impaired fatty acid oxidation. Owing to the potential effect of TM6SF2 deficiency on lipid metabolism, the application of an acetyl-CoA carboxylase inhibitor (MK-4074) could reverse the NAFLD phenotypes caused by TM6SF2 deficiency.

CONCLUSION

TM6SF2 plays a protective role in the HFD condition; its deficiency enhanced hepatic lipid accumulation through dysregulated fatty acid metabolism, and MK-4074 treatment could alleviate the NAFLD phenotypes caused by TM6SF2 deficiency.

Analysis of current status of quantitative detection of biomarkers for liver fibrosis in Clinical labs in China

Aim

To explore the quality control and implementation of the quantitative detection of liver fibrosis biomarkers, laminin (LN), collagen IV (Col Ⅳ), procollagen III amino‐terminal propeptide (PⅢNP), hyaluronic acid (HA), and cholyglycine (CG), in China.

Methods

Two quality control products were measured in different laboratories using different measurement methods and reagents, and the acquired results were subjected to analysis. The quantitative detection technique was based on the conventional assessment criteria, with a target value ±30% being employed.

Results

Hundred labs were involved in the External Quality Assessment with 88 laboratories completing the assessment, and the pass rates were 84%, 80.2%, 67.5%, 77.3%, and 58.3% for HA, LN, PⅢNP, Col Ⅳ, and CG, respectively. Chemiluminescence immunoassay was used most for HA (90.1%), LN (90.1%), PⅢNP (87.9%), and Col Ⅳ (82.9%) determination, whereas the chemiluminescence immunoassay (31.6%), latex‐enhanced immunoturbidimetry (36.7%), and homogeneous enzyme immunoassay (26.7%) were used for CG determination. The coefficients of variation for HA, LN, PⅢNP, Col Ⅳ, and CG in different laboratories were 3.3%–19.49%, 1.74%–38.81%, 1.97%–41.29%, 2.85%–41.69%, and 2.71%–41.8%, respectively.

Conclusion

The clinical quantitative detection of liver fibrosis biomarkers is highly performed in China. The existing problems are that there are many manufacturers producing reagents and instruments, the quality of reagents is uneven, the specificity and sensitivity of reagents are greatly different, the comparability of results of various systems is poor, and the accuracy and consistency between different systems are lacking. All above underscores the critical importance of EQA in improving and monitoring the identification of biomarkers for liver fibrosis.

Increase in Serum MMP-9 and TIMP-1 Concentrations during Alcohol Intoxication in Adolescents-A Preliminary Study

Background: Alcohol consumption by adolescents is responsible for a number of adverse health and social outcomes. Despite the well-established effect of alcohol use on the development of alcoholic liver disease, the relationship between the pattern of alcohol consumption and liver fibrosis is still unclear. This study is a follow-up to work on liver damage from alcohol intoxication. The aim of our study was to explore the early effects of alcohol intoxication on liver fibrosis in adolescents. Methods: The prospective study included 57 adolescents aged 14−17 years admitted to the emergency department (ED) from February 2017 to June 2018 due to acute alcohol intoxication. Serum levels of amino terminal propeptide of type III procollagen (PIIINP), type IV collagen, matrix metallopeptidase 9 (MMP-9) and tissue inhibitor of metalloproteinase 1 (TIMP-1) were determined by enzyme-linked immunosorbent assays. Results: There were significant differences in MMP-9 (p = 0.02) and TIMP-1 (p = 0.007) levels between the study and control groups. Liver parameters and selected markers of fibrosis were similar in groups in terms of blood alcohol concentrations (BAC). MMP-9 was positively correlated with alanine aminotransferase (ALT) (r = 0.38; p = 0.004) and total bilirubin (r = 0.39; p = 0.004). Positive significant correlations were also found between TIMP-1 and ALT (r = 0.47; p < 0.001), AST (r = 0.29; p = 0.03) and total bilirubin (r = 0.32; p = 0.02). In receiver operating characteristic (ROC) analysis, MMP-9 (AUC = 0.67, p = 0.02) and TIMP-1 (AUC = 0.69, p = 0.003) allowed for the differentiation of patients with and without alcohol intoxication. Conclusion: Our results show that even a single episode of alcohol intoxication in adolescents can lead to imbalance in markers of fibrosis.

Melatonin relieves liver fibrosis induced by Txnrd3 knockdown and nickel exposure via IRE1/NF-kB/NLRP3 and PERK/TGF-β1 axis activation

AIMS

Nickel(Ni) accumulates in the environment due to human activities such as electroplating, alloy production, stainless steel, Ni‑cadmium batteries and industrial production. Ni enriched in humans and animals through food chains, poses a serious health threat. Txnrd3, as a member of the thioredoxin reductase family, has long been thought to be testicular specific and involved in sperm maturation. However, its role in liver diseases still unknown. Melatonin exerts its antioxidant effects directly through its ability to clear free radicals and protects the liver from oxidative damage. Hepatic fibrosis with an ever-increasing incidence year by year, is correlating with outcome and risk of hepatocellular carcinoma.

MATERIALS AND METHODS

In this study, 60 8-week-old male C57BL/6 wild-type mice and 60 Txnrd3-/- mice were randomly divided into three groups, respectively. Control group was gavaged with distilled water, 10 mg/kg NiCl₂ in Ni group, Ni + Mel group treated with 2 mg/kg melatonin in the morning, 10 mg/kg NiCl₂ in the afternoon, serum and tissue was extracted after 21 days.

KEY FINDINGS

Results showed that liver function was significantly worse after Ni exposure, morphological and masson staining showed more significant liver fibrosis in Txnrd3-/- mice, damage of organelles in hepatocytes was observed. qPCR and WB results showed activation of the IRE1/Nuclear factor-kappa B/NLRP3 axis during Ni exposure lead to hepatocyte pyroptosis, while upregulation of PERK/TGF-β promoted liver fibrosis process and Txnrd3 knockout exacerbated liver damage during Ni exposure.

SIGNIFICANCE

The above results will lay the theoretical foundation for the monitoring and clinical treatment of Ni exposure.

High fibrosis-4 index predicts the new onset of ischaemic heart disease during a 10-year period in a general population

Aims

The fibrosis-4 (FIB-4) index, calculated using age, platelet count, and levels of aspartate aminotransferase and alanine aminotransferase, is a non-invasive indicator for the detection of liver fibrosis. Advanced hepatic fibrosis is associated with morbidity and mortality in patients with non-alcoholic fatty liver disease. However, the relationship between liver fibrosis and the development of ischaemic heart disease (IHD) has not fully been addressed.

Methods and results

We investigated the association between the FIB-4 index and the new onset of IHD during a 10-year period in a general population of subjects who received annual health examinations (n = 28 990). After exclusion of subjects with missing data and those with a history of IHD at baseline, a total of 13 448 subjects (men/women: 8774/4674, mean age: 48 years) were included. During the 10-year period, 378 men (4.3%) and 77 women (1.6%) had a new onset of IHD. Multivariable Cox proportional hazard models with a restricted cubic spline showed that hazard risk for the development of IHD increased with a higher FIB-4 index at baseline after adjustment of age, sex, fatty liver (FL) determined by ultrasonography, estimated glomerular filtration rate, habits of current smoking and alcohol drinking, family history of IHD, and diagnosis of hypertension, diabetes mellitus and dyslipidaemia. When divided by FL, the FIB-4 index becomes an independent predictor for the development of IHD in subjects with FL but not in those without FL. The addition of the FIB-4 index to traditional risk factors for IHD significantly improved the discriminatory capability.

Conclusion

A high level of the FIB-4 index predicts the new onset of IHD during a 10-year period.

The molecular phenotypes of injury, steatohepatitis, and fibrosis in liver transplant biopsies in the INTERLIVER study

To extend previous molecular analyses of rejection in liver transplant biopsies in the INTERLIVER study (ClinicalTrials.gov #NCT03193151), the present study aimed to define the gene expression selective for parenchymal injury, fibrosis, and steatohepatitis. We analyzed genome-wide microarray measurements from 337 liver transplant biopsies from 13 centers. We examined expression of genes previously annotated as increased in injury and fibrosis using principal component analysis (PCA). PC1 reflected parenchymal injury and related inflammation in the early posttransplant period, slowly regressing over many months. PC2 separated early injury from late fibrosis. Positive PC3 identified a distinct mildly inflamed state correlating with histologic steatohepatitis. Injury PCs correlated with liver function and histologic abnormalities. A classifier trained on histologic steatohepatitis predicted histologic steatohepatitis with cross-validated AUC = 0.83, and was associated with pathways reflecting metabolic abnormalities distinct from fibrosis. PC2 predicted histologic fibrosis (AUC = 0.80), as did a molecular fibrosis classifier (AUC = 0.74). The fibrosis classifier correlated with matrix remodeling pathways with minimal overlap with those selective for steatohepatitis, although some biopsies had both. Genome-wide assessment of liver transplant biopsies can not only detect molecular changes induced by rejection but also those correlating with parenchymal injury, steatohepatitis, and fibrosis, offering potential insights into disease mechanisms for primary diseases.

Prevalence of metabolic syndrome in cirrhotics with gastric antral vascular ectasia

BACKGROUND AND AIMS

Gastric antral vascular ectasia (GAVE) is characterized by angliodysplastic lesions that can cause upper gastrointestinal bleeding (UGIB). The mechanism behind GAVE and its association with other diseases remains unknown. We investigated the association of metabolic syndrome in cirrhotic GAVE patients when compared to esophageal variceal hemorrhage (EVH) patients.

METHODS

We performed a retrospective review of 941 consecutive esophagogastroduodenoscopies (EGDs) for UGIB at a medical center between 2017 and 2019. The GAVE group consisted of EGD or biopsy diagnosed cirrhotic GAVE patients, and the EVH group consisted of EVH patients with active bleeding or stigmata of recent hemorrhage on EGD. Baseline variables including co-morbidities and cirrhotic etiology were recorded. Continuous variables were compared using Wilcoxon test and categorical variables were compared using Chi-square or Fisher's exact test. Multiple logistic regression analysis evaluated the association between GAVE and covariates.

RESULTS

The final cohort had 96 GAVE and 104 EVH patients. Mean BMI was significantly higher in the GAVE cohort (32.6 vs 27.9, p < 0.0001) in addition to diabetes, hypertension, and hyperlipidemia (53.1% vs 37.5%; 76% vs 47.1%; 38.5% vs 14.4%; respectively, all p < 0.05). Non-alcoholic steatohepatitis (NASH) cirrhosis was more prevalent in GAVE than EVH patients (50% vs 24%, p = 0.0001). Multiple logistics regression revealed female sex, increased BMI, hypertension, and hyperlipidemia all having significantly higher risk of GAVE (all p < 0.05).

CONCLUSION

Our data indicates that when compared to cirrhotics patients with EVH, cirrhotics with GAVE have increased risk of metabolic syndrome. This may play a role in the underlying pathophysiology of GAVE.

Green Plant Pigment, Chlorophyllin, Ameliorates Non-alcoholic Fatty Liver Diseases (NAFLDs) Through Modulating Gut Microbiome in Mice

Non-alcoholic fatty liver diseases (NAFLDs) along with metabolic syndrome and Type-2 diabetes (T2D) are increasingly prevalent worldwide. Without an effective resolution, simple hepatic steatosis may lead to non-alcoholic steatohepatitis (NASH), characterized by hepatocyte damage, chronic inflammation, necrosis, fatty degeneration, and cirrhosis. The gut microbiome is vital for metabolic homeostasis. Conversely, dysbiosis contributes to metabolic diseases including NAFLD. Specifically, diet composition is critical for the enterotype of gut microbiota. We reasoned that green pigment rich in vegetables may modulate the gut microbiome for metabolic homeostasis. In this study, C57BL/6 mice under a high fat diet (HFD) were treated with sodium copper chlorophyllin (CHL), a water-soluble derivative of chlorophyll, in drinking water. After 28 weeks of HFD feeding, liver steatosis was established accompanied by gut microbiota dysbiosis, intestinal impairment, endotoxemia, systemic inflammation, and insulin resistance. Administration of CHL effectively alleviated systemic and intestinal inflammation and maintained tight junction in the intestinal barrier. CHL rebalanced gut microbiota in the mice under high fat feeding and attenuated hepatic steatosis, insulin resistance, dyslipidemia, and reduced body weight. Fecal flora transplants from the CHL-treated mice ameliorated steatosis as well. Thus, dietary green pigment or the administration of CHL may maintain gut eubiosis and intestinal integrity to attenuate systemic inflammation and relieve NASH.

Application of ultrasound elastography for monitoring the effects of TβR1 shRNA therapy on hepatic fibrosis in a rat model

BACKGROUND

To investigate the application of ultrasound elastography in monitoring the effects of the transforming growth factor (TGF)-β1 signaling pathway-targeted combination therapy for hepatic fibrosis.

METHODS

1. Short hairpin RNA (shRNA) constructs targeted towards TβR1 were designed, synthesized, and packaged using an adeno-associated virus (AAV), and the effective target shRNA was selected based on transfection results. 2. Fifty rats were randomly allocated (n = 10 per group) to the (A) control group, (B) model group, (C) 0-week therapy group, (D) 4-week therapy group, and (E) combination therapy group. At weeks 2, 4, 6, 8, 10, and 12, acoustic radiation force impulse (ARFI) elastography was used to measure the liver stiffness, inner diameter of the portal vein diameter, and blood velocity; radio frequency ultrasound imaging was used to measure the abdominal aortic elasticity parameter and pulse wave velocity (PWV) of the rats. 3. At week 12, portal vein puncture was performed to measure the portal venous pressure, and rat liver specimens were obtained for the pathological measurement of the degree of hepatic fibrosis.

RESULTS

1. An shRNA interference sequence targeted towards TβR1 was successfully designed, screened, and packaged using an AAV, and small-animal imaging results indicated expression of the specific shRNA in the liver. 2. At week 12, the ultrasound elastography results were significantly different between the experimental groups and the control group (p < 0.01); among the experimental groups, differences were significant between the therapy groups and the model group (p < 0.01). For groups C and E, the therapeutic effects on hepatic fibrosis in rats were significant, with the pathological results indicating a significant reduction in the degree of hepatic fibrosis (p < 0.01). The therapeutic effectiveness of group D was less than that of group C (p < 0.05). Significant differences existed between the portal venous pressure of the experimental groups and of the control group (p < 0.01). For the abdominal aortic elasticity parameter measured by radio frequency ultrasound imaging, differences existed between the values obtained from the experimental groups and from that of the control group (p < 0.05), while statistically significant differences were not found among the various experimental groups. 3. Continuous ultrasound examination results indicated that the elasticity value of group A was significantly different from those of the other groups after 2 weeks of model establishment (p < 0.01); after 6 weeks, the elasticity values of groups C and E were significantly different compared with those of groups B and D (p < 0.01). For the abdominal aortic elasticity parameter and pulse wave velocity (PWV), there were no significant differences among the various groups (p > 0.05).

CONCLUSION

CCl4-induced hepatic fibrosis can be treated through shRNA silencing of TβR1. Ultrasound ARFI elastography is superior to external force-assisted elastography as it can reflect the degree of fibrosis in moderate to severe hepatic fibrosis and the variations in the degree of fibrosis after treatment. Portal venous pressure was positively correlated with the degree of fibrosis; with early combination therapy, both the degree of fibrosis and portal venous pressure could be effectively reduced.

Clinical indicators for progression of nonalcoholic steatohepatitis to cirrhosis

Non-alcoholic fatty liver disease (NAFLD), is a disease spectrum characterized by fat accumulation in hepatocytes presenting as hepatic steatosis to advance disease with active hepatic inflammation, known as nonalcoholic steatohepatitis. Chronic steatohepatitis will lead to progressive hepatic fibrosis causing cirrhosis and increased risk for developing hepatocellular carcinoma (HCC). Fatty liver disease prevalence has increased at alarming rates alongside obesity, diabetes and metabolic syndrome to become the second most common cause of cirrhosis after alcohol related liver disease worldwide. Given this rise in prevalence, it is becoming increasingly more important to find non-invasive methods to diagnose disease early and stage hepatic fibrosis. Providing clinicians with the tools to diagnose and treat the full spectrum of NAFLD will help prevent known complications such as cirrhosis and HCC and improve quality of life for the patients suffering from this disease. This article discusses the utility of current non-invasive liver function testing in the clinical progression of fatty liver disease along with the imaging modalities that are available. Additionally, we summarize available treatment options including targeted medical therapy through four different pathways, surgical or endoscopic intervention.

Effect of acupuncture combined with Shenqi Yigan Decoction on liver function and T cell subsets in patients with HBV-induced liver fibrosis

OBJECTIVE

To explore the effect of acupuncture combined with Shenqi Yigan Decoction on liver function and T cell subsets in patients with Hepatitis B virus-induced liver fibrosis.

METHODS

All of the 90 patients with HBV-induced liver fibrosis were divided into two groups with the control group (n=45) treated with the conventional treatment, and the observation group (n=45) treated with acupuncture and Shenqi Yigan decoction based on the observation group. The seroconversion rate of hepatitis Be antigen (HBeAg), the liver function, the serum indexes of liver fibrosis of hyaluronic acid (HA), laminin (LN), type III procollagen (PC III), type IV collagen (IV-C), the T cell subsets and the inflammatory factors were compared between the two groups.

RESULTS

After 2 and 4 months of treatment, the HBeAg seroconversion rate of patients in the observation group was higher than that of the control group, but the difference was not significant (P>0.05). And the HBeAg seroconversion rate of patients in the observation group was significantly higher than that of the control group after 6 months treatment (P<0.05). After treatment, the serum levels of the liver function index of aspartate aminotransferase (AST), alanine aminotransferase (ALT), total bilirubin (Tbil), the liver fibrosis index of HA, LN, PC III, and the inflammatory factor of type IV collagen (IV-C), C-reactive protein (CRP) and tumor necrosis factor-α (TNF-α) in the two groups were lower than those before treatment, in addition, the levels of there index were lower in the observation group (all P<0.05). After treatment, the proportion of CD3⁺, CD4⁺ T lymphocyte subsets and CD4⁺/CD8⁺ in peripheral blood of the two groups were increased, and the proportion of CD8⁺ was decreased. The change range of the observation group was larger than that of the observation group (all P<0.01). The proportion of patients with liver fibrosis grade F1 in the observation group after treatment was significantly higher than that before treatment, and the proportion of patients with liver fibrosis grade F2 to F3 was significantly lower than that before treatment. There was a significant difference in liver fibrosis grade between the two groups after treatment (P<0.05).

CONCLUSION

The combined treatment of acupuncture and Shenqi Yigan decoction can significantly improve the liver function of patients with HBV-induced liver fibrosis, delay the progress of liver fibrosis, improve the cellular immune function and reduce the inflammatory reaction.

Efficacy of the fibrosis index for predicting end-stage renal disease in patients with antineutrophil cytoplasmic antibody-associated vasculitis

OBJECTIVE

Kidney involvement is a major manifestation of antineutrophil cytoplasmic antibody-associated vasculitis (AAV) and may progress to end-stage renal disease (ESRD), requiring renal replacement therapy. Unfortunately, there is no reliable kidney-specific index for predicting the progression of renal disease to ESRD. The fibrosis index (FI) reflects the degree of fibrosis in chronic liver disease. This study aimed to investigate whether the FI at the time of diagnosis could predict the development of ESRD in AAV patients.

METHODS

We retrospectively reviewed the medical records of 211 immunosuppressive drug-naïve AAV patients and extrapolated the cut-off FI value for predicting the development of ESRD using receiver operating characteristic curves. The associations between the FI and clinical outcomes, including mortality, relapse, and ESRD development, were determined.

RESULTS

Overall, 39 (18.5%) patients developed ESRD owing to the progression of AAV-associated renal disease. The median FI was higher in AAV patients with ESRD than in those without (1.61 vs 1.04; P = .001). The FI cut-off was 1.72. The incidence of ESRD was higher in patients with FI ≥ 1.72 at the time of diagnosis than in those with an FI < 1.72 at the time of diagnosis (relative risk: 4.655; 95% confidence interval: 2.242-9.662; P < .001). Kaplan-Meier survival analysis revealed that patients with an FI ≥ 1.72 at the time of diagnosis exhibited significantly lower ESRD-free survival rates than those with an FI < 1.72 at the time of diagnosis (P < .001).

CONCLUSION

FI ≥ 1.72 at the time of diagnosis may be an independent predictive marker for ESRD in AAV patients.

Performance of Noninvasive Liver Fibrosis Tests in Morbidly Obese Patients with Nonalcoholic Fatty Liver Disease

Background

Nonalcoholic fatty liver disease (NAFLD) is highly prevalent in morbidly obese patients, and fibrosis is an independent predictor of mortality. Noninvasive tests (NITs) are being developed for the detection of advanced fibrosis (AF).

Purpose

To assess the performance of three NITs (NAFLD fibrosis score, NFS, fibrosis-4 index, FIB-4, and aspartate aminotransferase-to-platelet ratio, APRI), in the identification of AF among morbidly obese patients.

Materials and Methods

Patients, who underwent bariatric surgery between 2004 and 2009 and had liver biopsy, were included. Fibrosis stages ≥ F2 and ≥ F3 were defined as significant and AF, respectively. Published and optimal thresholds (Youden index) for NFS, FIB-4 and APRI, sensitivity, specificity, positive and negative predictive values (PPV-NPV), and area under the receiver operator curves (AUROC) were evaluated.

Results

Among 584 patients (mean age 43.3 ± 11.3 years, 21.2% male, 75% white, mean BMI 45.5 ± 8.80), 31.7% had NASH. Stages distributions were F1 = 68.1%, F2 = 16.4%, F3 = 8%, and F4 = 3.2%. At published thresholds, all 3 NITs performed poorly for detection of AF, with AUROC < 0.62. Overall performance at optimal thresholds improved to 0.68, 0.72, and 0.74 for NFS, FIB-4, and APRI, respectively. At optimal thresholds, all tests had good NPV (94.4–95.9%) but low PPV (24.2–32.5%). Combinations of the tests did not improve their performance.

Conclusions

NFS, FIB-4, and APRI fall short to detect advanced fibrosis but valuable for excluding advanced fibrosis. More research is needed to develop new NITs with high positive predictive value.

Electronic supplementary material

The online version of this article (10.1007/s11695-020-04996-1) contains supplementary material, which is available to authorized users.

Non-alcoholic fatty liver disease: molecular and cellular interplays of the lipid metabolism in a steatotic liver

INTRODUCTION

Non-alcoholic fatty liver disease (NAFLD) affects ~25% of world population and cases have increased in recent decades. These anomalies have several etiologies; however, obesity and metabolic dysfunctions are the most relevant causes. Despite being considered a public health problem, no effective therapeutic approach to treat NAFLD is available. For that, a deep understanding of metabolic routes that support hepatic diseases is needed.

AREAS COVERED

This review covers aspects of the onset of NAFLD. Thereby, biochemistry routes as well as cellular and metabolic effects of the gut microbiota in body's homeostasis and epigenetics are contextualized.

EXPERT OPINION

Recently, the development of biological sciences has generated innovative knowledge, bringing new insights and perspectives to clarify the systems biology of liver diseases. A detailed comprehension of epigenetics mechanisms will offer possibilities to develop new therapeutic and diagnostic strategies for NAFLD. Different epigenetic processes have been reported that are modulated by the environment such as gut microbiota, suggesting strong interplays between cellular behavior and pathology. Thus, a more complete description of such mechanisms in hepatic diseases will help to clarify how to control the establishment of fatty liver, and precisely describe molecular interplays that potentially control NAFLD.

Honokiol Alleviates Methionine-Choline Deficient Diet-Induced Hepatic Steatosis and Oxidative Stress in C57BL/6 Mice by Regulating CFLAR-JNK Pathway

Background

Honokiol (HNK) has been reported to possess various beneficial effects in the context of metabolic disorders, including fatty liver, insulin resistance, and oxidative stress which are closely related to nonalcoholic steatohepatitis (NASH), however with no particular reference to CFLAR or JNK.

Methods

C57BL/6 mice were fed methionine-choline-deficient (MCD) diet and administered simultaneously with HNK (10 and 20 mg/kg once a day, ig) for 6 weeks, and NCTC1469 cells were pretreated, respectively, by oleic acid (OA, 0.5 mmol/L) plus palmitic acid (PA, 0.25 mmol/L) for 24 h, and adenovirus-down Cflar for 24 h, then exposed to HNK (10 and 20 μmol/L) for 24 h. Commercial kits, H&E, MT, ORO staining, RT-qPCR, and Western blotting were used to detect the biomarkers, hepatic histological changes, and the expression of key genes involved in NASH.

Results

The in vivo results showed that HNK suppressed the phosphorylation of JNK (pJNK) by activating CFLAR; enhanced the mRNA expression of lipid metabolism-related genes Acox, Cpt1α, Fabp5, Gpat, Mttp, Pparα, and Scd-1; and decreased the levels of hepatic TG, TC, and MDA, as well as the levels of serum ALT and AST. Additionally, HNK enhanced the protein expression of oxidative stress-related key regulatory gene NRF2 and the activities of antioxidases HO-1, CAT, and GSH-Px and decreased the protein levels of prooxidases CYP4A and CYP2E1. The in vivo effects of HNK on the expression of CLFAR, pJNK, and NRF2 were proved by the in vitro experiments. Moreover, HNK promoted the phosphorylation of IRS1 (pIRS1) in both tested cells and increased the uptake of fluorescent glucose 2-NBDG in OA- and PA-pretreated cells.

Conclusions

HNK ameliorated NASH mainly by activating the CFLAR-JNK pathway, which not only alleviated fat deposition by promoting the efflux and β-oxidation of fatty acids in the liver but also attenuated hepatic oxidative damage and insulin resistance by upregulating the expression of NRF2 and pIRS1.

Advanced-age C57BL/6JRj mice do not develop obesity upon western-type diet exposure

Obesity has become a global health-threat for every age group. It is well known that young mice (10-12 weeks of age) fed a western-type diet (WD) become obese and develop higher cholesterol levels and liver steatosis whereas insulin sensitivity is reduced. Less is known, however, about the effect of a WD on advanced-age mice. Therefore, 10 week-old (young) and 22 month-old (advanced-age), male C57BL/6JRj mice were kept on either a WD or a control diet (SFD) for 15 weeks. In contrast to young mice, advanced-age mice on WD did not show a higher body weight or adipose tissue (AT)-masses, suggesting a protection against diet-induced obesity. Furthermore, plasma adiponectin and leptin levels were not affected upon WD-feeding. A WD, however, did induce more hepatic lipid accumulation as well as increased hepatic expression of the macrophage marker F4/80, in advanced-age mice. There were no significant differences in mRNA levels of uncoupling protein-1 or F4/80 in brown AT (BAT) or of several intestinal integrity markers in colon suggesting that the protection against obesity is not due to excessive BAT or to impaired intestinal absorption of fat. Thus, advanced-age mice, in contrast to their younger counterparts, appeared to be protected against diet-induced obesity.

Understanding the association of polycystic ovary syndrome and non-alcoholic fatty liver disease

Polycystic ovary syndrome (PCOS) is the most common endocrine disorder among reproductive-age women. Patients with non-alcoholic fatty liver disease (NAFLD) often suffer from metabolic syndrome, atherosclerosis, ischemic heart disease, and extrahepatic tumors, conferring a lower survival than the general population; therefore it is crucial to study the association between NAFLD and PCOS since it remains poorly understood. Insulin resistance (IR) plays a central role in the pathogenesis of NAFLD and PCOS; also, hyperandrogenism enhances IR in these patients. IR, present in the NAFLD-PCOS association could decrease the hepatic production of sex hormone-binding globulin through a possible regulation mediated by hepatocyte nuclear factor 4 alpha. On the other hand, apoptotic processes initiated by androgens actively contribute to the progression of NAFLD. Considering the association between the two conditions, the screening of women with PCOS for the presence of NAFLD appears reasonable. The pathophysiological mechanisms of PCOS-NAFLD association and the initial approach will be reviewed here.

Multi-level remodeling of transcriptional landscapes in aging and longevity

In multi-cellular organisms, the control of gene expression is key not only for development, but also for adult cellular homeostasis, and gene expression has been observed to be deregulated with aging. In this review, we discuss the current knowledge on the transcriptional alterations that have been described to occur with age in metazoans. First, we discuss age-related transcriptional changes in protein-coding genes, the expected functional impact of such changes, and how known pro-longevity interventions impact these changes. Second, we discuss the changes and impact of emerging aspects of transcription in aging, including age-related changes in splicing, lncRNAs and circRNAs. Third, we discuss the changes and potential impact of transcription of transposable elements with aging. Fourth, we highlight small ncRNAs and their potential impact on the regulation of aging phenotypes. Understanding the aging transcriptome will be key to identify important regulatory targets, and ultimately slow-down or reverse aging and extend healthy lifespan in humans.

Effects of sleeve gastrectomy on liver enzymes, non-alcoholic fatty liver disease-related fibrosis and steatosis scores in morbidly obese patients: first year follow-up

Background

Non-alcoholic fatty liver disease (NAFLD) has a high prevalence among patients undergoing laparoscopic sleeve gastrectomy (LSG). Although liver biopsy is the gold standard for assessing histopathologic changes in the liver, it is an invasive procedure. The objective of this study was to evaluate the effect of sleeve gastrectomy on liver enzymes, fibrosis and steatosis scores; ultrasonographic findings; biochemical parameters; and anthropometric measurements in morbidly obese patients with NAFLD.

Methods

Ninety-seven obese patients who underwent LSG were included in this study. Sex, age, body mass index (BMI), comorbidities, liver enzymes, ultrasonographic findings and laboratory parameters to calculate fibrosis and steatosis scores were collected before surgery and after 1 year of follow-up.

Results

A total of 88.7% of patients had liver steatosis at the pre-surgical ultrasonographic evaluation and this ratio decreased to 46.4% 1 year after surgery. Alanine aminotransferase (ALT), homeostatic model assessment of insulin resistance index (HOMA-IR), aspartate aminotransferase-to-platelet ratio index (APRI) and liver fat score (LFS) were significantly higher in patients with steatosis grade III vs. others. There were improvements in high-density lipoprotein (HDL), triglycerides (TG), glycated hemoglobin (HbA1c), glucose, insulin, BMI, liver enzymes and all NAFLD-related fibrosis and steatosis scores.

Conclusions

HOMA-IR, ALT, LFS and APRI scores can be used for follow-up procedures in morbidly obese patients with NAFLD who underwent LSG.

The FATZO mouse, a next generation model of type 2 diabetes, develops NAFLD and NASH when fed a Western diet supplemented with fructose

BACKGROUND

Metabolic disorders such as insulin resistance, obesity, and hyperglycemia are prominent risk factors for the development of non-alcoholic fatty liver disease (NAFLD)/steatohepatitis (NASH). Dietary rodent models employ high fat, high cholesterol, high fructose, methionine/choline deficient diets or combinations of these to induce NAFLD/NASH. The FATZO mice spontaneously develop the above metabolic disorders and type 2 diabetes (T2D) when fed with a normal chow diet. The aim of the present study was to determine if FATZO mice fed a high fat and fructose diet would exacerbate the progression of NAFLD/NASH.

METHODS

Male FATZO mice at the age of 8 weeks were fed with high fat Western diet (D12079B) supplemented with 5% fructose in the drinking water (WDF) for the duration of 20 weeks. The body weight, whole body fat content, serum lipid profiles and liver function markers were examined monthly along with the assessment of liver histology for the development of NASH. In addition, the effects of obeticholic acid (OCA, 30 mg/kg, QD) on improvement of NASH progression in the model were evaluated.

RESULTS

Compared to normal control diet (CD), FATZO mice fed with WDF were heavier with higher body fat measured by qNMR, hypercholesterolemia and had progressive elevations in AST (~ 6 fold), ALT (~ 6 fold), liver over body weight (~ 2 fold) and liver triglyceride (TG) content (1.4-2.9 fold). Histological examination displayed evidence of NAFLD/NASH, including hepatic steatosis, lobular inflammation, ballooning and fibrosis in FATZO mice fed WDF. Treatment with OCA for 15 weeks in FATZO mice on WDF significantly alleviated hypercholesterolemia and elevation of AST/ALT, reduced liver weight and liver TG contents, attenuated hepatic ballooning, but did not affect body weight and blood TG levels.

CONCLUSION

WDF fed FATZO mice represent a new model for the study of progressive NAFLD/NASH with concurrent metabolic dysregulation.

Adenovirus 5 produces obesity and adverse metabolic, morphological, and functional changes in the long term in animals fed a balanced diet or a high-fat diet: a study on hamsters

Adenovirus 5 (Ad-5) infection is a common cause of acute respiratory infections and the main vector used in gene therapy. There are few studies on the relationship of Ad-5 to obesity. In the present study, we evaluated the chronic effects of Ad-5 infection on golden (Syrian) hamsters fed either a balanced diet (BD) or a high-fat diet (HFD). After a single inoculation with Ad-5 (1 × 10⁷ pfu), the body weight of the animals was measured weekly. Medium-term (22 weeks) serum biochemical analyses and long-term (44 weeks) liver morphology, adiposity, and locomotive functionality (movement velocity) assessments were carried out. In the animals fed the BD, adenovirus infection produced hyperglycemia and hyperlipidemia. In the long term, it produced a 57% increase in epididymal pad fat and a 30% body weight gain compared with uninoculated animals. In addition, morphological changes related to non-alcoholic fatty liver disease (NAFLD) were observed. The animals fed the HFD had similar but more severe changes. In addition, the hamsters presented an obesity paradox: at the end of the study, the animals that had the most morphological and functional changes (significantly reduced movement velocity) had the lowest body weight. Despite the fact that an HFD appears to be a more harmful factor in the long term than adenovirus infection alone, infection could increase the severity of harmful effects in individuals with an HFD. Epidemiological studies are needed to evaluate the effect of adenovirus as a precursor of chronic liver and cardiovascular diseases, including the chronic effects of gene therapy.

Current status, problems, and perspectives of non-alcoholic fatty liver disease research

Non-alcoholic fatty liver disease (NAFLD) is a major chronic liver disease that can lead to liver cirrhosis, liver cancer, and ultimately death. NAFLD is pathologically classified as non-alcoholic fatty liver (NAFL) or non-alcoholic steatohepatitis (NASH) based on the existence of ballooned hepatocytes, although the states have been known to transform into each other. Moreover, since the detection of ballooned hepatocytes may be difficult with limited biopsied specimens, its clinical significance needs reconsideration. Repeated liver biopsy to assess histological NAFLD activity for therapeutic response is also impractical, creating the need for body fluid biomarkers and less invasive imaging modalities. Recent longitudinal observational studies have emphasized the importance of advanced fibrosis as a determinant of NAFLD outcome. Thus, identifying predictors of fibrosis progression and developing better screening methods will enable clinicians to isolate high-risk NAFLD patients requiring early intensive intervention. Despite the considerable heterogeneity of NAFLD with regard to underlying disease, patient age, and fibrosis stage, several clinical trials are underway to develop a first-in-class drug. In this review, we summarize the present status and future direction of NAFLD/NASH research towards solving unmet medical needs.

Multi-level remodeling of transcriptional landscapes in aging and longevity

In multi-cellular organisms, the control of gene expression is key not only for development, but also for adult cellular homeostasis, and gene expression has been observed to be deregulated with aging. In this review, we discuss the current knowledge on the transcriptional alterations that have been described to occur with age in metazoans. First, we discuss age-related transcriptional changes in protein-coding genes, the expected functional impact of such changes, and how known pro-longevity interventions impact these changes. Second, we discuss the changes and impact of emerging aspects of transcription in aging, including age-related changes in splicing, lncRNAs and circRNAs. Third, we discuss the changes and potential impact of transcription of transposable elements with aging. Fourth, we highlight small ncRNAs and their potential impact on the regulation of aging phenotypes. Understanding the aging transcriptome will be key to identify important regulatory targets, and ultimately slow-down or reverse aging and extend healthy lifespan in humans. [BMB Reports 2019; 52(1): 86-108].

The diagnostic and initial approach of the patient with non-alcoholic fatty liver disease: role of the primary care provider

Non-alcoholic fatty liver disease (NAFLD) represents a broad spectrum of liver damage, ranging from simple steatosis to steatohepatitis and fibrosis; as well, there is a close association between NAFLD, obesity, metabolic syndrome and type 2 diabetes mellitus. There is a certain degree of uncertainty regarding the natural history and prognosis of NAFLD; however, several methods are currently used for its diagnostic approach. In the first instance, non-invasive tests could be used to identify patients at low risk of developing fibrosis and to establish more easily the need for a liver biopsy, whose accuracy in the evaluation of fibrosis has been questioned, mainly due to errors of intra and interobserver sampling, technical problems and cost, which limits its use. Therefore, it is essential to determine the diagnostic strategy for patients with NAFLD.

CXC Motif Ligand 16 Promotes Nonalcoholic Fatty Liver Disease Progression via Hepatocyte-Stellate Cell Crosstalk

CONTEXT

Nonalcoholic fatty liver disease (NAFLD) is a focus of attention because of its prevalence. CXC motif ligand 16 (CXCL16) has been studied in inflammatory and metabolic diseases.

OBJECTIVE

To investigate the role of CXCL16 in steatosis and fibrosis in patients with NAFLD.

DESIGN

Liver specimens and sera of patients with NAFLD were collected from 2012 to 2017.

SETTING

Beijing 302 Hospital.

PARTICIPANTS

117 patients with NAFLD and 15 healthy controls.

INTERVENTIONS

None.

MAIN OUTCOME MEASURES

The main outcome measures were CXCL16 levels in sera and biopsy specimens of patients with NAFLD.

RESULTS

CXCL16 serum level was markedly elevated in patients with NAFLD, especially in those at the S3 steatosis level according to the steatosis, activity, and fibrosis (SAF) scoring system. The different serum levels of CXCL16 between groups were due to data in patients with A or F scores ≥2, according to the SAF scoring system. CXCL16 accumulated around steatotic hepatocytes in biopsy specimens. In vitro, CXCL16 treatment led to severe steatosis of hepatocytes in the hepatocyte-stellate cell coculture system and suppressed the respiration rate of hepatocytes. Lipogenic gene expression and hepatic stellate cell activation indexes were increased in a CXCL16 overexpression system. In addition, ligands in the Hedgehog pathway cascade were downregulated in hepatocytes.

CONCLUSIONS

CXCL16 was highly expressed in patients with NAFLD, suggesting that it may contribute to steatotic and fibrotic progression. CXCL16 may be a potential noninvasive marker of NAFLD and a future potential therapeutic target to treat NAFLD.

Ginseng-plus-Bai-Hu-Tang ameliorates diet-induced obesity, hepatic steatosis, and insulin resistance in mice

Background

Dietary fat has been suggested to be the cause of various health issues. Obesity, hypertension, cardiovascular disease, diabetes, dyslipidemia, and kidney disease are known to be associated with a high-fat diet (HFD). Obesity and associated conditions, such as type 2 diabetes mellitus and nonalcoholic fatty liver disease (NAFLD), are currently a worldwide health problem. Few prospective pharmaceutical therapies that directly target NAFLD are available at present. A Traditional Chinese Medicine, ginseng-plus-Bai-Hu-Tang (GBHT), is widely used by diabetic patients to control glucose level or thirst. However, whether it has therapeutic effects on fat-induced hepatic steatosis and metabolic syndrome remains unclear.

Methods

This study was conducted to examine the therapeutic effect of GBHT on fat-induced obesity, hepatic steatosis, and insulin resistance in mice.

Results

GBHT protected mice against HFD-induced body weight gain, hyperlipidemia, and hyperglycemia compared with mice that were not treated. GBHT inhibited the expansion of adipose tissue and adipocyte hypertrophy. No ectopic fat deposition was found in the livers of HFD mice treated with GBHT. In addition, glucose intolerance and insulin sensitivity in HFD mice was also improved by GBHT.

Conclusion

GBHT prevents changes in lipid and carbohydrate metabolism in a HFD mouse model. Our findings provide evidence for the traditional use of GBHT as therapy for the management of metabolic syndrome.

Importance of the Average Glucose Level and Estimated Glycated Hemoglobin in a Diabetic Patient with Hereditary Hemolytic Anemia and Liver Cirrhosis

Glycated hemoglobin (HbA1c) is a widely used marker of glycemic control but can be affected by hemolytic anemia. Glycated albumin (GA) is also affected in patients with liver cirrhosis. We herein report the assessment of glycemic control in a 41-year-old man with dehydrated hereditary stomatocytosis and a PIEZO1 gene mutation complicated by diabetes mellitus and liver cirrhosis due to hemochromatosis. The estimated HbA1c calculated from the average glucose level obtained by continuous glucose monitoring or by self-monitoring of blood glucose was useful for evaluating the glycemic control in this patient, as HbA1c and GA were unreliable due to the coexisting conditions.

The Influence of Extracellular RNA on Cell Behavior in Health, Disease and Regeneration

PURPOSE OF REVIEW

An overview of the role of extracellular RNAs (exRNA) in the regulation of homeostasis, disease progression, and regeneration is provided herein. Several exRNAs have been identified as potential biomarkers for disease and disease progression. In addition, the potential of exRNAs as a therapeutic modality is discussed.

RECENT FINDINGS

Fibrotic diseases of the lung, liver, and heart, among other organs share a number of identical exRNAs which play key roles in disease pathogenesis. Though regeneration is limited to only a few tissues in humans, small RNAs (e.g. microRNA) have been shown to be involved in the regenerative process of tissues such as liver and bone. The regulation of healing versus disease appears to be balanced by small RNAs. Because small RNAs are critical to health, they are being investigated as drug targets in multiple ongoing clinical trials. Preclinical studies suggest that promoting or blocking specific small RNAs can provide a novel therapeutic approach.

SUMMARY

exRNA can be utilized for both detection and treatment of disease. Natural and synthetic RNA carriers are being investigated as delivery methods for small RNA molecules. Current and future investigations are likely to lead to expanded applications for exRNAs.

Involvement of the hepatobiliary system and pancreas in obesity

The article provides an overview of current views on the involvement of the liver, gallbladder, and pancreas in patients with overweight and obesity. It considers the general issues of the pathogenesis of these conditions, their clinical features and diagnostic methods.

Bibliometric analysis of top 100 cited articles in nonalcoholic fatty liver disease research

AIM

To identify and assess the research situation of top 100 cited articles in nonalcoholic fatty liver disease (NAFLD).

METHODS

The global scientific research articles in the Science Citation Index-Expanded relevant to NAFLD were retrieved and listed according to their citation times from the most to the least. The 100 most frequently cited original articles were selected to systematically evaluate their bibliometric parameters including times cited, publication year, journals, subject categories, and the highly related concepts of NAFLD, which reflected the history and current situation, publication distribution of leading countries and institutes as well as the research hotspots of NAFLD.

RESULTS

Top 100 cited articles in NAFLD were published from 1965 to 2015 with a citation ranging of 227 to 2151 times since publication, in which the United States was the most predominant country and Mayo Clin was the most productive institution. The majority of the top 100 cited articles were concentrated in SCI subject category of Gastroenterology and Hepatology. Hepatology and Gastroenterology is the top journal that published over half 100 top-cited articles. The significant peak of top cited articles present in the first half of the 2000s while the highest mean number of citation presents in first half of the 1980s. In addition, concepts related to pathology characteristics, epidemiology and medicalization, metabolic syndrome and its combination of symptoms including insulin resistance, biomarkers of lipid metabolism and obesity are listed as the highly related concepts.

CONCLUSION

The 100 top-cited articles marked with the leading countries, institutions, journals, hotspots and development trend in NAFLD field that could provide the foundation for further investigations.

Hepatic gadoxetic acid uptake as a measure of diffuse liver disease: Where are we?

MRI has emerged as the most comprehensive noninvasive diagnostic tool for focal liver lesions and diffuse hepatobiliary disorders. The introduction of hepatobiliary contrast agents, most notably gadoxetic acid (GA), has expanded the role of MRI, particularly in the functional imaging of chronic liver diseases, such as nonalcoholic fatty liver disease (NAFLD). GA-enhanced MRI (GA-MRI) may help to distinguish between the two subgroups of NAFLD, simple steatosis and nonalcoholic steatohepatitis. Furthermore, GA-MRI can be used to stage fibrosis and cirrhosis, predict liver transplant graft survival, and preoperatively estimate the risk of liver failure should major resection be undertaken. The amount of GA uptake can be estimated, using static images, by the relative liver enhancement, hepatic uptake index, and relaxometry of T1-mapping during the hepatobiliary phase. On the contrary, the hepatic extraction fraction and liver perfusion can be measured on dynamic imaging. Importantly, there is currently no clear consensus as to which of these MR-derived parameters is the most suitable for assessing liver dysfunction. This review article aims to describe the current role of GA-enhanced MRI in quantifying liver function, primarily in diffuse hepatobiliary disorders.

LEVEL OF EVIDENCE

3 J. Magn. Reson. Imaging 2017;45:646-659.

Clinical significance of serum Wisteria floribunda agglutinin positive Mac-2-binding protein level in non-alcoholic steatohepatitis

AIM

To examine the relationship between the Wisteria floribunda agglutinin positive Mac-2-binding protein (WFA⁺ -M2BP) level and histological findings for patients with non-alcoholic steatohepatitis (NASH).

METHODS

A total of 134 NASH patients (mean age, 51.7 years) were analyzed. We examined the effect of WFA⁺ -M2BP level on severity of liver fibrosis comparing with other laboratory markers, including aspartate aminotransferase (AST) to alanine aminotransferase (ALT) ratio, AST to platelet ratio index (APRI), FIB-4 index, platelet count and hyaluronic acid as serum liver fibrosis markers. Receiver-operator curve (ROC) analysis was performed for calculating the area under the ROC (AUROC).

RESULTS

The WFA⁺ -M2B P-value ranged from 0.2 cut-off index (COI) to 9.6 COI (median, 0.9). The median values in each fibrosis stage were: 0.7 COI in F1, 0.7 COI in F2, 1.2 COI in F3 and 2.4 COI in F4 (P < 0.001). For predicting liver cirrhosis (F4), WFA⁺ -M2BP level had the AUROC of 0.854 (sensitivity, 69.2%; specificity, 88.4%) and for predicting advanced liver fibrosis (≥F3), WFA⁺ -M2BP level yielded the second highest AUROC with a level of 0.842 (sensitivity, 73.7%; specificity, 80.2%) and for predicting significant liver fibrosis (≥F2), WFA⁺ -M2BP level yielded the highest AUROC with a level of 0.663 (sensitivity, 47.2%; specificity, 78.6%) among six liver fibrosis markers. The median values in patients with ballooning scores 1 (n = 58) and 2 (n = 76) were 0.6 and 1.1 COI, respectively (P < 0.001).

CONCLUSION

Serum WFA⁺ -M2BP level can be useful for assessing liver histological findings in patients with NASH.

Hedgehog signaling is a potent regulator of liver lipid metabolism and reveals a GLI-code associated with steatosis

Non-alcoholic fatty liver disease (NAFLD) is the most common liver disease in industrialized countries and is increasing in prevalence. The pathomechanisms, however, are poorly understood. This study assessed the unexpected role of the Hedgehog pathway in adult liver lipid metabolism. Using transgenic mice with conditional hepatocyte-specific deletion of Smoothened in adult mice, we showed that hepatocellular inhibition of Hedgehog signaling leads to steatosis by altering the abundance of the transcription factors GLI1 and GLI3. This steatotic 'Gli-code' caused the modulation of a complex network of lipogenic transcription factors and enzymes, including SREBP1 and PNPLA3, as demonstrated by microarray analysis and siRNA experiments and could be confirmed in other steatotic mouse models as well as in steatotic human livers. Conversely, activation of the Hedgehog pathway reversed the "Gli-code" and mitigated hepatic steatosis. Collectively, our results reveal that dysfunctions in the Hedgehog pathway play an important role in hepatic steatosis and beyond.

DOI:http://dx.doi.org/10.7554/eLife.13308.001

The liver is one of the main organs responsible for processing everything that mammals eat and drink. Nutrients absorbed by the gut like sugars and lipids (fats) are processed by the liver and are stored or distributed to provide energy to other organs. Sometimes these metabolic processes become unbalanced. This can lead to lipids accumulating in the liver – a process known as steatosis, which is a feature of human non-alcoholic fatty liver disease.

In organs like the liver, cells are instructed how to behave via signaling pathways. A protein outside the cell signals to specific proteins inside, which switch on a set of target genes. One such pathway is the Hedgehog pathway, which primarily regulates tissue regeneration and the development of embryos. A component of this pathway is the Smoothened gene, which indirectly switches on proteins called GLI factors that regulate metabolic genes, including those involved in lipid metabolism. The Hedgehog pathway has been found to control the metabolism of lipids in fat tissue but it is not known whether it is important for lipid metabolism in the liver.

Matz-Soja et al. investigated this possible role of the Hedgehog pathway in the liver using mice with a Smoothened gene that could be deleted specifically in that organ. This deletion disrupted Hedgehog signaling and led to lipids accumulating in the liver and eventually to steatosis. These changes were associated with an increase in the amounts and activityof several enzymes (and the proteins that regulate these enzymes) that help to synthesize lipids. Steatosis was also associated with low amounts of two of the three GLI factors; indeed, this seems to be key for triggering problems with lipid metabolism. Human livers with steatosis showed the same changes in levels of the GLI factors.

Increasing the amount of GLI factors in liver cells taken from mice with steatosis reduced the accumulation of lipids and brought lipid metabolism back to its normal balance. A focus of future studies will be to understand how the Hedgehog signaling pathway interacts with other signaling pathways known to regulate liver lipid metabolism, such as insulin signaling. This knowledge will help clinicians to design new treatments for lipid-associated diseases like non-alcoholic fatty liver disease.

DOI:http://dx.doi.org/10.7554/eLife.13308.002