Adipokines in liver diseases

Intrahepatic angiopoietin-2 correlates with chronic hepatitis C progression and is induced in hepatitis C virus replicon systems

BACKGROUND & AIMS

Chronic hepatitis C (CHC) is a major cause of cirrhosis and hepatocellular carcinoma and angiogenesis is closely related to the pathogenesis and progression of different chronic liver diseases (CLD). Thus, the intrahepatic expression of angiopoietins 1 and 2 (Ang1 and Ang2), as relevant mediators of pathological angiogenesis in several CLD, was investigated. In addition, the differential influence of structural and non-structural genomic regions of HCV on the expression of angiopoietins and the possible signalling involved were studied.

METHODS

Ang1 and Ang2 expression was evaluated by western blotting and enzyme-linked immunosorbent assay (ELISA) in liver homogenates of CHC patients (n=47) and uninfected subjects (n=8). Their association with disease progression (according to METAVIR classification) was assessed by Spearman's correlation. Statistical differences among the expression of angiopoietins at different CHC stages were calculated by Mann-Whitney U-test. Finally, the in vitro expression of Angiopoietins in HCV replicons (complete or non-structural subgenomic) and the main signalling pathways involved were also examined.

RESULTS

Ang2 levels were significantly higher in the liver of CHC patients compared to controls and significantly correlated with inflammation and fibrosis. Accordingly, an increased expression of Ang2 was found in all HCV replicons tested. Interestingly, the inhibition of MEK and PI3K signalling pathways exerted differential effects on Ang2 expression concerning to the genomic region of HCV.

CONCLUSIONS

Hepatitis C virus induces Ang2 expression in hepatocytes through different signalling routes which may lead to the disregulation of vascular homeostasis in the liver. Thus, pharmacologic intervention on Ang2 signalling might constitute an important therapeutic tool.

The human longevity gene homolog INDY and interleukin-6 interact in hepatic lipid metabolism

Reduced expression of the Indy ("I am Not Dead, Yet") gene in lower organisms promotes longevity in a manner akin to caloric restriction. Deletion of the mammalian homolog of Indy (mIndy, Slc13a5) encoding for a plasma membrane-associated citrate transporter expressed highly in the liver, protects mice from high-fat diet-induced and aging-induced obesity and hepatic fat accumulation through a mechanism resembling caloric restriction. We studied a possible role of mIndy in human hepatic fat metabolism. In obese, insulin-resistant patients with nonalcoholic fatty liver disease, hepatic mIndy expression was increased and mIndy expression was also independently associated with hepatic steatosis. In nonhuman primates, a 2-year high-fat, high-sucrose diet increased hepatic mIndy expression. Liver microarray analysis showed that high mIndy expression was associated with pathways involved in hepatic lipid metabolism and immunological processes. Interleukin-6 (IL-6) was identified as a regulator of mIndy by binding to its cognate receptor. Studies in human primary hepatocytes confirmed that IL-6 markedly induced mIndy transcription through the IL-6 receptor and activation of the transcription factor signal transducer and activator of transcription 3, and a putative start site of the human mIndy promoter was determined. Activation of the IL-6-signal transducer and activator of transcription 3 pathway stimulated mIndy expression, enhanced cytoplasmic citrate influx, and augmented hepatic lipogenesis in vivo. In contrast, deletion of mIndy completely prevented the stimulating effect of IL-6 on citrate uptake and reduced hepatic lipogenesis. These data show that mIndy is increased in liver of obese humans and nonhuman primates with NALFD. Moreover, our data identify mIndy as a target gene of IL-6 and determine novel functions of IL-6 through mINDY.

CONCLUSION

Targeting human mINDY may have therapeutic potential in obese patients with nonalcoholic fatty liver disease. German Clinical Trials Register: DRKS00005450. (Hepatology 2017;66:616-630).

A Nutrigenomic Approach to Non-Alcoholic Fatty Liver Disease

Following the epidemics of obesity due to the consumption of high-calorie diet and sedentary lifestyle, nonalcoholic fatty liver disease (NAFLD) is now the leading cause of liver disease in Western countries. NAFLD is epidemiologically associated with metabolic syndrome and insulin resistance, and in susceptible individuals it may progress to cirrhosis and hepatocellular carcinoma. Genetic factors play a key role in NAFLD predisposition by interacting with nutritional and other environmental factors. To date, there is no drug therapy for the treatment of NAFLD, and the main clinical recommendation is lifestyle modification. In the last years, nutrigenomics is promoting an increased understanding of how nutrition affects the switch from health to disease by altering the expression of an individual’s genetic makeup. The present review tries to summarize the most recent data evidencing how the interactions between nutrients and genetic factors can influence NAFLD development. The final goal should be to develop tools to quantify these complex interactions. The definition of a “nutrigenomic risk score” for each individual may represent a novel therapeutic approach for the management of NAFLD patients.

Hepatogenous diabetes: Is it time to separate it from type 2 diabetes?

By definition, hepatogenous diabetes is directly caused by loss of liver function, implying that it develops after cirrhosis onset. Therefore, it should be distinguished from type 2 diabetes developing before cirrhosis onset, in which specific causes of liver disease play a major role, in addition to traditional risk factors. Currently, although hepatogenous diabetes shows distinct pathophysiological and clinical features, it is not considered as an autonomous entity. Recent evidence suggests that the failing liver exerts an independent "toxic" effect on pancreatic islets resulting in β-cell dysfunction. Moreover, patients with hepatogenous diabetes usually present with normal fasting glucose and haemoglobin A_1c levels and abnormal response to an oral glucose tolerance test, which is therefore required for diagnosis. This article discusses the need to separate hepatogenous diabetes from type 2 diabetes occurring in subjects with chronic liver disease and to identify individuals suffering from this condition for prognostic and therapeutic purposes.

Non-alcoholic fatty liver disease: A sign of systemic disease

Non-alcoholic fatty liver disease (NAFLD) is the most common form of liver disease and leading cause of cirrhosis in the United States and developed countries. NAFLD is closely associated with obesity, insulin resistance and metabolic syndrome, significantly contributing to the exacerbation of the latter. Although NAFLD represents the hepatic component of metabolic syndrome, it can also be found in patients prior to their presentation with other manifestations of the syndrome. The pathogenesis of NAFLD is complex and closely intertwined with insulin resistance and obesity. Several mechanisms are undoubtedly involved in its pathogenesis and progression. In this review, we bring together the current understanding of the pathogenesis that makes NAFLD a systemic disease.

Development of hepatocellular cancer induced by long term low fat-high carbohydrate diet in a NAFLD/NASH mouse model

Nonalcoholic fatty liver disease (NAFLD) is a common chronic liver disease. It can progress to nonalcoholic steatohepatitis (NASH) and, in a percentage of cases, to hepatocarcinogenesis. The strong incidence in western countries of obesity and metabolic syndrome, whose NAFLD is the hepatic expression, is thought to be correlated to consumption of diets characterized by processed food and sweet beverages. Previous studies described high-fat diet-induced liver tumors. Conversely, the involvement of low-fat/high-carbohydrate diet in the progression of liver disease or cancer initiation has not been described yet. Here we show for the first time hepatic cancer formation in low-fat/high-carbohydrate diet fed NAFLD/NASH mouse model. Animals were long term high-fat, low-fat/high-carbohydrate or standard diet fed. We observed progressive liver damage in low-fat/high-carbohydrate and high-fat animals after 12 and, more, 18 months. Tumors were detected in 20% and 50% of high-fat diet fed mice after 12 and 18 months and, interestingly, in 30% of low-fat/high-carbohydrate fed animals after 18 months. No tumors were detected in standard diet fed mice. Global increase of hepatic interleukin-1β, interleukin-6, tumor necrosis factor-α and hepatocyte growth factor was detected in low-fat/high-carbohydrate and high-fat with respect to standard diet fed mice as well as in tumor with respect to non-tumor bearing mice. A panel of 15 microRNAs was analyzed: some of them revealed differential expression in low-fat/high-carbohydrate with respect to high-fat diet fed groups and in tumors. Data here shown provide the first evidence of the involvement of low-fat/high-carbohydrate diet in hepatic damage leading to tumorigenesis.

Insulin resistance promotes Lysyl Oxidase Like 2 induction and fibrosis accumulation in non-alcoholic fatty liver disease

In patients with non-alcoholic fatty liver disease (NAFLD), insulin resistance (IR) associates with fibrosis progression independently of the hepatic inflammation, but the mechanisms are still unclear. We modeled the independent contribution of inflammation (non-alcoholic steatohepatitis: NASH) by exploiting the methionine-choline deficient (MCD) diet, and that of IR by insulin receptor (InsR) haploinsufficiency (InsR+/-) in the pathogenesis of liver fibrosis in C57BL/6 mice. We confirmed the study findings in 96 patients with NAFLD. InsR+/- enhanced hepatic fat content and impaired hepatic insulin signaling leading to Forkhead box protein O1 (FoxO1) accumulation in MCD-fed mice. Remarkably, despite reduced inflammation and hampered transdifferentiation of hepatic stellate cells (HSCs), InsR+/- promoted hepatic fibrosis accumulation, which correlated with the induction of the Lysyl Oxidase Like 2 (Loxl2), involved in matrix stabilization. Loxl2 up-regulation was not a cell autonomous property of insulin resistant HSCs, but was dependent on microparticles (MPs) released specifically by insulin resistant hepatocytes (HEPs) exposed to fatty acids. The mechanism entailed FoxO1 up-regulation, as FoxO1 silencing normalized Loxl2 expression reversing fibrosis in InsR+/- MCD-fed mice. Loxl2 up-regulation was similarly detected during IR induced by obesity, but not by lipogenic stimuli (fructose feeding). Most importantly, LOXL2 up-regulation was observed in NAFLD patients with type 2 diabetes (T2D) and LOXL2 hepatic and circulating levels correlated with histological fibrosis progression. IR favors fibrosis deposition independently of the classic 'inflammation - HSC transdifferentiation' pathway. The mechanism entails a cross-talk between enhanced lipotoxicity in insulin resistant HEPs and Loxl2 production by HSCs, which was confirmed in patients with diabetes, thereby facilitating extracellular matrix (ECM) stabilization.

Adipose tissue autophagy and homeostasis in alcohol-induced liver injury

Alcohol consumption leads to injury in multiple organs and systems, including the liver, brain, heart, skeletal muscle, pancreas, bone, immune system, and endocrine system. Emerging evidence indicates that alcohol also promotes adipose tissue dysfunction, which may contribute to injury progression in other organs and systems. Autophagy is a lysosomal degradation pathway that has been shown to regulate adipose tissue homeostasis and adipogenesis. Increasing evidence also demonstrates that alcohol consumption affects autophagy in multiple tissues. This review summarizes current knowledge regarding the effect of autophagy on adipose tissue and its potential roles in alcohol-induced adipose tissue atrophy as well as its contribution to alcohol-induced liver injury.

Impact of Skeletal Muscle Mass Index, Intramuscular Adipose Tissue Content, and Visceral to Subcutaneous Adipose Tissue Area Ratio on Early Mortality of Living Donor Liver Transplantation

BACKGROUND

Skeletal muscle depletion has been shown to be an independent risk factor for poor survival in various diseases. However, in surgery, the significance of other body components including visceral and subcutaneous adipose tissue remains unclear.

METHODS

This retrospective study included 250 adult patients undergoing living donor liver transplantation (LDLT) between January 2008 and April 2015. Using preoperative plain computed tomography imaging at the third lumbar vertebra level, skeletal muscle mass, muscle quality, and visceral adiposity were evaluated by the skeletal muscle mass index (SMI), intramuscular adipose tissue content (IMAC), and visceral to subcutaneous adipose tissue area ratio (VSR), respectively. The cutoff values of these parameters were determined for men and women separately using the data of 657 healthy donors for LDLT between 2005 and 2016. Impact of these parameters on outcomes after LDLT was analyzed.

RESULTS

VSR was significantly correlated with patient age (P = 0.041), neutrophil-lymphocyte ratio (P < 0.001), body mass index (P < 0.001), and SMI (P = 0.001). The overall survival probability was significantly lower in patients with low SMI (P < 0.001), high IMAC (P < 0.001), and high VSR (P < 0.001) than in each respective normal group. On multivariate analysis, low SMI (hazard ratio [HR], 2.367, P = 0.002), high IMAC (HR, 2.096, P = 0.004), and high VSR (HR, 2.213, P = 0.003) were identified as independent risk factors for death after LDLT.

CONCLUSIONS

Preoperative visceral adiposity, as well as low muscularity, was closely involved with posttransplant mortality.

AISF position paper on nonalcoholic fatty liver disease (NAFLD): Updates and future directions

This review summarizes our current understanding of nonalcoholic fatty liver disease (NAFLD), a multi-factorial systemic disease resulting from a complex interaction between a specific genetic background and multiple environmental/metabolic "hits". The role of gut microbiota, lipotoxicity, inflammation and their molecular pathways is reviewed in-depth. We also discuss the epidemiology and natural history of NAFLD by pinpointing the remarkably high prevalence of NAFLD worldwide and its inherent systemic complications: hepatic (steatohepatitis, advanced fibrosis and cirrhosis), cardio-metabolic (cardiovascular disease, cardiomyopathy, arrhythmias and type 2 diabetes) and neoplastic (primary liver cancers and extra-hepatic cancers). Moreover, we critically report on the diagnostic role of non-invasive biomarkers, imaging techniques and liver biopsy, which remains the reference standard for diagnosing the disease, but cannot be proposed to all patients with suspected NAFLD. Finally, the management of NAFLD is also reviewed, by highlighting the lifestyle changes and the pharmacological options, with a focus on the innovative drugs. We conclude that the results of ongoing studies are eagerly expected to lead to introduce into the clinical arena new diagnostic and prognostic biomarkers, prevention and surveillance strategies as well as to new drugs for a tailored approach to the management of NAFLD in the individual patient.

Circulating irisin levels as a predictive biomarker for sarcopenia: A cross-sectional community-based study

AIM

Myokines are peptides released by the skeletal muscle, and have gained popularity as potential biomarkers for sarcopenia. Irisin is a recently identified myokine, but its role in pathological sarcopenia remains unclear. We investigated the validity and accuracy of circulating irisin levels as a potential biomarker for sarcopenia.

METHODS

We evaluated the anthropometrics, body composition, sarcopenia-related parameters and serum irisin levels of 715 community-dwelling Koreans. Sarcopenia was determined on the basis of the clinical diagnostic criteria of muscle atrophy and weakness, which were proposed by the Asian Working Group for Sarcopenia.

RESULTS

Circulating irisin levels were correlated with appendicular lean mass/height² (r_men = 0.275; r_women = 0.321) and handgrip strength (r_men = 0.219; r_women = 0.312) in both sexes (all P < 0.01). Furthermore, the mean circulating irisin levels were lower in the sarcopenia group than in the normal group (all P < 0.05). In the logistic regression models, the association between serum irisin concentration and incident sarcopenia persisted even after adjusting for potential confounders, such as sex, age and fat indices (odds ratio 0.20, 95% CI 0.07-0.60; P for trend <0.01). The predictive values of serum irisin for sarcopenia were <1.0 μg/mL in men and <1.16 μg/mL in women, with the area under the receiver operating characteristic curves of 0.87 (95% CI 0.77-0.99) and 0.68 (95% CI 0.55-0.81), respectively (all P < 0.01).

CONCLUSIONS

A low level of circulating irisin is a sensitive marker for muscle weakness and atrophy. Irisin is a potential biomarker for muscle dysfunction that could help predict the onset of sarcopenia and provide new avenues for monitoring age-related muscle changes. Geriatr Gerontol Int 2017; 17: 2266-2273.

Reversal of liver cirrhosis: current evidence and expectations

In the past, liver cirrhosis was considered an irreversible phenomenon. However, many experimental data have provided evidence of the reversibility of liver fibrosis. Moreover, multiple clinical studies have also shown regression of fibrosis and reversal of cirrhosis on repeated biopsy samples. As various etiologies are associated with liver fibrosis via integrated signaling pathways, a comprehensive understanding of the pathobiology of hepatic fibrogenesis is critical for improving clinical outcomes. Hepatic stellate cells play a central role in hepatic fibrogenesis upon their activation from a quiescent state. Collagen and other extracellular material components from activated hepatic stellate cells are deposited on, and damage, the liver parenchyma and vascular structures. Hence, inactivation of hepatic stellate cells can lead to enhancement of fibrolytic activity and could be a potential target of antifibrotic therapy. In this regard, continued efforts have been made to develop better treatments for underlying liver diseases and antifibrotic agents in multiple clinical and therapeutic trials; the best results may be expected with the integration of such evidence. In this article, we present the underlying mechanisms of fibrosis, current experimental and clinical evidence of the reversibility of liver fibrosis/cirrhosis, and new agents with therapeutic potential for liver fibrosis.

CTRP1 in Liver Disease

Nonalcoholic fatty liver disease (NAFLD) is a chronic liver disease occurs in significant percentage of general population. NAFLD is closely associated with entire spectrum of metabolic-related disorders including diabetes, obesity, and cardiovascular diseases. Considering several similar pathways underpinning metabolic disorders, presence of common molecular mediators contributing to pathomechanism of these disorders is expected. Mounting evidence has demonstrated important role of adipokines in the context of NAFLD. Adipokines produced by different tissues, mainly adipose, modulate numerous pathways including glucose and fatty acid metabolism and inflammation. CTRPs (C1q/TNF-related proteins) are a recently identified family of adipokines in which adiponectin is the most well-known ones. CTRP1 is a member of this family which has captured attention in recent years. CTRP1 enhances glucose and fatty acid oxidation, improves insulin sensitivity, attenuates plaque formation, and increases aldosterone production. Hence, various roles in metabolic pathways can link CTRP1 to NAFLD pathogenesis.

The association of variants in PNPLA3 and GRP78 and the risk of developing hepatocellular carcinoma in an Italian population

Hepatocellular carcinoma (HCC) has one of the worst prognoses amongst all malignancies. It commonly arises in patients with established liver disease and the diagnosis often occurs at an advanced stage. Genetic variations, such as single nucleotide polymorphisms (SNPs), may alter disease risk and thus may have use as predictive markers of disease outcome. The aims of this study were (i) to assess the association of two SNPs, rs430397 in GRP78 and rs738409 in PNPLA3 with the risk of developing HCC in a Sicilian association cohort and, (ii) to use a machine learning technique to establish a predictive combinatorial phenotypic model for HCC including rs430397 and rs738409 genotypes and clinical and laboratory attributes. The controls comprised of 304 healthy subjects while the cases comprised of 170 HCC patients the majority of whom had hepatitis C (HCV)-related cirrhosis. Significant associations were identified between the risk of developing HCC and both rs430397 (p=0.0095) and rs738409 (p=0.0063). The association between rs738409 and HCC was significantly stronger in the HCV positive cases. In the best prediction model, represented graphically by a decision tree with an acceptable misclassification rate of 17.0%, the A/A and G/A genotypes of the rs430397 variant were fixed and combined with the three rs738409 genotypes; the attributes were age, sex and alcohol. These results demonstrate significant associations between both rs430397 and rs738409 and HCC development in a Sicilian cohort. The combinatorial predictive model developed to include these genetic variants may, if validated in independent cohorts, allow for earlier diagnosis of HCC.

CXCL12 expression and PD-L1 expression serve as prognostic biomarkers in HCC and are induced by hypoxia

Anti-PD-1 treatment increases anti-tumour immune responses in animal models of hepatocellular carcinoma (HCC). Sorafenib, the mainstay of treatment of HCC patients, however, leads to tumour hypoxia and thereby abrogates the efficacy of anti-PD-1 treatment. This served as a rationale to implement CXCR4 inhibition as adjunct to sorafenib and anti-PD-1 treatment in murine HCC models. We studied the relationship between tumour hypoxia, PD-L1 and CXCL12 expression in human HCC, aiming to test the rationale for triple therapy combining sorafenib, PD-1 immune checkpoint inhibitors and CXCR4 inhibitors. Expression of CXCL12, PD-L1 and of surrogate markers for tumour hypoxia was evaluated at messenger RNA (mRNA) level in a cohort of HCC patients from The Cancer Genome Atlas and immunohistochemically in an independent cohort from the University Hospital of Bonn. Retrospective survival analyses were conducted. CXCL12 mRNA level significantly correlated with markers indicating tumour hypoxia in HCC (HIF1-α ρ = 0.104, p = 0.047). PD-L1 expression was significantly increased in tumours with a high number of tumour-infiltrating lymphocytes (ρ = 0.533, p < 0.001). In Cox proportional hazard analyses, high PD-L1 expression and loss of nuclear CXCL12 expression showed significant prognostic value in terms of overall survival (hazard ratio (HR) = 3.35 [95%CI 1.33-8.46], p = 0.011 for PD-L1; HR = 2.64 [95%CI 1.18-5.88], p = 0.018 for CXCL12, respectively). This study supports the rationale to combine CXCR4 inhibitors and PD-1 immune checkpoint inhibitors in patients with HCC, as sorafenib-induced tumour hypoxia leads to upregulation of PD-L1 and CXCL12.

Nonalcoholic fatty liver disease: cause or consequence of type 2 diabetes?

Growing epidemiological evidence suggests that nonalcoholic fatty liver disease (NAFLD) is an early predictor of and determinant for the development of type 2 diabetes and other features of the metabolic syndrome. This finding may have important clinical implications for the diagnosis, prevention and treatment of type 2 diabetes and its chronic complications. However, given the complex and bi-directional relationships between NAFLD, insulin resistance and chronic hyperglycaemia, it is extremely difficult to distinguish whether NAFLD is a cause or a consequence of insulin resistance and type 2 diabetes. Indeed, at the molecular level, hepatic lipogenesis and hepatic glucose production depend on differentially regulated branches of the insulin signalling pathway. Furthermore, genetic studies suggest that excess hepatic fat is associated with progressive liver disease, but does not always increase the risk of incident type 2 diabetes. Here, we will briefly review the epidemiological, pathophysiological and molecular evidence linking NAFLD to the development of type 2 diabetes. We will also discuss some recent genetic and therapeutic advances that seem to challenge a causal role of NAFLD in the pathogenesis type 2 diabetes, and propose a working hypothesis to explain this apparent conundrum. In conclusion, progressive liver disease and type 2 diabetes are divergent though inter-related consequences of insulin resistance and the metabolic syndrome.

SERUM LEPTIN LEVENS AND HEPATOCELLULAR CARCINOMA: REVIEW ARTICLE

Introduction

Hepatocellular carcinoma is one of the most frequent types of malignant tumors in the world. There is growing evidence of the relationship between it development and obesity. The mechanism that links obesity to cancer is still not fully understood; however, it is essential to the understanding the adipose tissue in metabolic changes related to obesity and hepatocellular carcinoma.

Objective

To review the influence of serum leptin levels in patients with hepatocelular carcinoma.

Method

Systematic review of the literature based on the methodology of the Cochrane Institute. The search for articles was in the database: Science Direct, Scielo, Medline, Lilacs e Pubmed. The key words used were hepatocellular carcinoma, leptin, adipokine.

Results

After evaluation of individual studies, were selected seven studies. The results previously studied are still inconsistent and contradictory, and leptin can be effectively involved in the occurrence and development of hepatocellular carcinoma.

Conclusion

Therefore, it is necessary to develop prospective, well-designed and conducted focusing on the role and specific mechanisms of this hormone in patients with hepatocellular carcinoma, so that new correlations can be properly supported.

Plasma, urine and ligament tissue metabolite profiling reveals potential biomarkers of ankylosing spondylitis using NMR-based metabolic profiles

Background

Ankylosing spondylitis (AS) is an autoimmune rheumatic disease mostly affecting the axial skeleton. Currently, anti-tumour necrosis factor α (anti-TNF-α) represents an effective treatment for AS that may delay the progression of the disease and alleviate the symptoms if the diagnosis can be made early. Unfortunately, effective diagnostic biomarkers for AS are still lacking; therefore, most patients with AS do not receive timely and effective treatment. The intent of this study was to determine several key metabolites as potential biomarkers of AS using metabolomic methods to facilitate the early diagnosis of AS.

Methods

First, we collected samples of plasma, urine, and ligament tissue around the hip joint from AS and control groups. The samples were examined by nuclear magnetic resonance spectrometry, and multivariate data analysis was performed to find metabolites that differed between the groups. Subsequently, according to the correlation coefficients, variable importance for the projection (VIP) and P values of the metabolites obtained in the multivariate data analysis, the most crucial metabolites were selected as potential biomarkers of AS. Finally, metabolic pathways involving the potential biomarkers were determined using the Kyoto Encyclopedia of Genes and Genomes (KEGG) database, and the metabolic pathway map was drawn.

Results

Forty-four patients with AS agreed to provide plasma and urine samples, and 30 provided ligament tissue samples. An equal number of volunteers were recruited for the control group. Multidimensional statistical analysis suggested significant differences between the patients with AS and control subjects, and the models exhibited good discrimination and predictive ability. A total of 20 different metabolites ultimately met the requirements for potential biomarkers. According to KEGG analysis, these marker metabolites were primarily related to fat metabolism, intestinal microbial metabolism, glucose metabolism and choline metabolism pathways, and they were also probably associated with immune regulation.

Conclusions

Our work demonstrates that the potential biomarkers that were identified appeared to have diagnostic value for AS and deserve to be further investigated. In addition, this work also suggests that the metabolomic profiling approach is a promising screening tool for the diagnosis of patients with AS.

Iron and non-alcoholic fatty liver disease

The mechanisms that promote liver injury in non-alcoholic fatty liver disease (NAFLD) are yet to be thoroughly elucidated. As such, effective treatment strategies are lacking and novel therapeutic targets are required. Iron has been widely implicated in the pathogenesis of NAFLD and represents a potential target for treatment. Relationships between serum ferritin concentration and NAFLD are noted in a majority of studies, although serum ferritin is an imprecise measure of iron loading. Numerous mechanisms for a pathogenic role of hepatic iron in NAFLD have been demonstrated in animal and cell culture models. However, the human data linking hepatic iron to liver injury in NAFLD is less clear, with seemingly conflicting evidence, supporting either an effect of iron in hepatocytes or within reticulo-endothelial cells. Adipose tissue has emerged as a key site at which iron may have a pathogenic role in NAFLD. Evidence for this comes indirectly from studies that have evaluated the role of adipose tissue iron with respect to insulin resistance. Adding further complexity, multiple strands of evidence support an effect of NAFLD itself on iron metabolism. In this review, we summarise the human and basic science data that has evaluated the role of iron in NAFLD pathogenesis.

Molecular Pathogenesis of NASH

Nonalcoholic steatohepatitis (NASH) is the main cause of chronic liver disease in the Western world and a major health problem, owing to its close association with obesity, diabetes, and the metabolic syndrome. NASH progression results from numerous events originating within the liver, as well as from signals derived from the adipose tissue and the gastrointestinal tract. In a fraction of NASH patients, disease may progress, eventually leading to advanced fibrosis, cirrhosis and hepatocellular carcinoma. Understanding the mechanisms leading to NASH and its evolution to cirrhosis is critical to identifying effective approaches for the treatment of this condition. In this review, we focus on some of the most recent data reported on the pathogenesis of NASH and its fibrogenic progression, highlighting potential targets for treatment or identification of biomarkers of disease progression.

KBH-1, an herbal composition, improves hepatic steatosis and leptin resistance in high-fat diet-induced obese rats

Background

KBH-1 is an herbal mixture of Saururus chinensis, Curcuma longa and Polygala tenuifolia. Each herb has been reported to have various pharmaceutical activities; however, the synergistic effect of this herbal composition on obesity has not yet been determined. We investigated the alleviation effect of KBH-1 and its possible molecular mechanism in obesity-induced hepatic steatosis and leptin resistance in the hypothalamus.

Methods

We used HepG2 cells, primary neuronal cells and a high-fat diet (HFD)-induced obesity rat model to determine the effect of KBH-1 in vitro and in vivo on hepatic steatosis and leptin resistance accompanied by obesity. To identify the alleviation effect on lipid accumulation, HepG2 cells stimulated by FFA were stained with Oil Red O; in addition, immunoblotting and qPCR were performed to determine the effect of KBH-1 on the activation of proteins and nuclear enzymes in HepG2 cells and the steatotic liver of HFD-induced obesity rats. To examine the effect of KBH-1 on the leptin resistance of the hypothalamus and its possible molecular mechanism, we examined the effect of KBH-1 on the activation of the leptin resistance-related protein in primary cultured cortical neuron cells and the hypothalamus of an HFD-induced obesity rat model. In addition, we used HPLC analysis to identify the standard compound of KBH-1.

Results

KBH-1 not only suppressed the lipid deposition in HepG2 cells exposed to free fatty acids (FFA) but also significantly down-regulated major factors in lipogenesis and up-regulated major factors in lipolysis. Similarly, in a HFD-induced obesity model, KBH-1 improved hepatic steatosis by alleviating the effects on lipogenic genes and kinases. In addition, KBH-1 significantly improved the leptin-mediated signals impaired by obesity or FFA in the obesity model and primary cultured cortical neuron cells. In addition, KBH-1 was analyzed to include six standard compounds using HPLC analysis, among these compounds, onji-saponin B and curcumin were potently suppressed the level of triglycerides.

Conclusions

KBH-1 exhibits alleviating effects by improving hepatic steatosis and leptin resistance by up-regulating the activation of AMPK and suppressing the expression of PPARγ. These findings show the potential of KBH-1 as a functional food supplement or preventive agent in the treatment of obesity.

Electronic supplementary material

The online version of this article (doi:10.1186/s12906-016-1265-z) contains supplementary material, which is available to authorized users.

Genetics of nonalcoholic fatty liver disease

Epidemiological, familial, and twin studies indicate that non-alcoholic fatty liver disease, now the leading cause of liver damage in developed countries, has a strong heritability. The common I148M variant of PNPLA3 impairing hepatocellular lipid droplets remodeling is the major genetic determinant of hepatic fat content. The I148M variant has a strong impact on the full spectrum of liver damage related to fatty liver, encompassing non-alcoholic steatohepatitis, advanced fibrosis, and hepatocellular carcinoma, and influences the response to therapeutic approaches. Common variants in GCKR enhance de novo hepatic lipogenesis in response to glucose and liver inflammation. Furthermore, the low-frequency E167K variant of TM6SF2 and rare mutations in APOB, which impair very low-density lipoproteins secretion, predispose to progressive fatty liver.

CONCLUSIONS

These and other recent findings reviewed here indicate that impaired lipid handling by hepatocytes has a major role in the pathogenesis of non-alcoholic fatty liver disease by triggering inflammation, fibrogenesis, and carcinogenesis. These discoveries have provided potential novel biomarkers for clinical use and have revealed intriguing therapeutic targets.

Resistin reinforces interferon λ-3 to eliminate hepatitis C virus with fine-tuning from RETN single-nucleotide polymorphisms

The effect of resistin (RETN) on the response to anti-HCV therapy remains unclear. A prospective cohort study was performed using 655 consecutive HCV patients, of whom 513 had completed a course of interferon-based therapy. Multivariate and GEE analyses revealed four RETN single-nucleotide polymorphisms (SNPs), rs34861192, rs3219175, rs3745367 and rs1423096, to be synergistically associated with resistin levels. After adjusting for co-factors such as interferon λ-3 (IFNL3)-rs12979860, the resistin level and the hyper-resistinemic genotype at the 4 RETN SNPs were positively and negatively associated with a sustained virological response (SVR), respectively. RETN-rs3745367 was in linkage disequilibrium with IFNL3-rs12979860. Compared to non-SVR patients, SVR patients had higher levels of pre-therapy resistin, primarily originating from intrahepatic lymphocytes, stellate cells, Kupffer cells, hepatic progenitor cells and hepatocytes. This difference diminished over the course of therapy, as only SVR patients exhibited a 24-week post-therapy decrease in resistin. Both resistin and IFNL3 mRNAs were upregulated, but only resistin mRNA was upregulated by recombinant resistin in peripheral blood mononuclear cells with and without hyper-resistinemic genotypes of the 4 RETN SNPs, respectively. Fine-tuned by RETN SNPs, intrahepatic, multi-cellular resistin reinforced IFNL3 in eliminating HCV via immunomodulation to counteract pro-inflammation. These results encourage the development of novel resistin-targeted anti-viral agents.

Similarities and differences between pediatric and adult nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) is highly common and potentially serious in children and adolescents. The term NAFLD refers to a spectrum of diseases ranging from accumulation of fat in the liver (simple steatosis or nonalcoholic fatty liver "NAFL") to the potentially progressive form of nonalcoholic steatohepatitis (NASH) characterized by hepatocyte ballooning, inflammation, and often associated with fibrosis. While large prospective longitudinal studies in pediatric NAFLD are still lacking, growing evidence suggests that children with NAFL are at increased risk for cardiometabolic complications, while those with NASH and advance fibrosis are also at risk for significant liver-related morbidity including cirrhosis and its complications. Pediatric NAFLD shares features of adult NAFLD but also shows many different characteristics in terms of prevalence, histology, diagnosis and management. Translational studies suggest that NAFLD is a highly heritable disease in which genetic variations and environment closely interact to determine the disease phenotype and the progression to the more advanced forms of the disease. Changes in lifestyle, targeting gradual weight reduction, and physical exercise continue to be the mainstay of treatment for NAFLD in children. Recent advances in development of noninvasive diagnostic modalities and the potential for identifying effective pharmacological interventions may result in significant progress in the management of NAFLD in the pediatric population.

Perspectives on Treatment for Nonalcoholic Steatohepatitis

It is important to provide treatment to patients with nonalcoholic steatohepatitis (NASH) because one third of patients with the metabolic syndrome die of liver disease. Basic research studies have elucidated mechanisms of NASH pathogenesis, which could lead to therapeutic targets. Health agencies have confirmed strategies for the optimal management of NASH and approved new drugs and treatments, which urgently are needed. The US Food and Drug Administration recently endorsed end points for NASH therapy. The reversal of NASH with no evidence of progression to advanced fibrosis has been defined as the end point for phase 2b and phase 3 trials in patients with NASH and early stage fibrosis. Although a decrease in the nonalcoholic fatty liver disease activity score could serve as an end point in clinical trials, it is not clear whether patients with lower scores have a lower risk of progression to advanced fibrosis. End points for clinical trials of patients with NASH cirrhosis currently are based on model for end-stage liver disease and Child-Pugh-Turcotte scores, as well as the hepatic venous pressure gradient. Different strategies are being explored to reduce liver diseases that are linked to a sedentary lifestyle, overeating, and genetic factors. In association with insulin resistance and deregulation of the lipid metabolism (accumulation of lipotoxins that promote hepatic lipogenesis, adipose tissue lipolysis, and impaired β-oxidation), these factors could increase the risk of liver steatosis with necroinflammatory lesions and fibrosis. We review the pathogenic mechanisms of NASH and therapeutic options, as well as strategies that are being developed for the treatment of injury to the liver and other organs.

Review article: emerging anti-fibrotic therapies in the treatment of non-alcoholic steatohepatitis

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) can lead to non-alcoholic steatohepatitis (NASH) and cirrhosis. Fibrosis predicts worse outcomes and mortality. New treatments targeting fibrosis are being investigated to reverse disease progression.

AIM

To review the new pipeline therapeutic agents targeting fibrosis in NASH patients, with particular focus on clinical trials in which reversing fibrosis and portal hypertension are the primary outcomes.

METHODS

The literature was searched in PubMed between January 2000 and January 2016 using search terms non-alcoholic fatty liver disease and NASH, with filters of 'English language'. We focused on fibrosis improvement as the key outcome. We also searched the ClinicalTrials.gov for promising agents that target fibrosis in NASH patients.

RESULTS

Significant advances have been made on approaches targeting fibrosis in NASH patients. Many therapeutic agents are already in development, some of which have shown promising results in preclinical and phase I studies. Novel therapies have entered phase II and III studies targeting fibrosis reversal and/or improvement in portal hypertension. Innovative studies have also started looking into combining these agents, aiming at different mechanisms to maximise therapeutic outcomes. We found five clinical trials in phase II and one in phase III focusing on fibrosis in NASH patients as key outcomes. One of the phase II trials is using combination therapy to target fibrosis.

CONCLUSIONS

Ongoing research studies are already investigating new pathways aimed at reversing fibrosis in NASH patients. Novel therapeutic agents are in development and are expected to offer unique options to NASH patients with advanced fibrosis.

Role of Serum Uric Acid and Ferritin in the Development and Progression of NAFLD

Nonalcoholic fatty liver disease (NAFLD), tightly linked to the metabolic syndrome (MS), has emerged as a leading cause of chronic liver disease worldwide. Since it is potentially progressive towards non-alcoholic steatohepatitis (NASH) and hepatic fibrosis, up to cirrhosis and its associated complications, the need for predictive factors of NAFLD and of its advanced forms is mandatory. Despite the current "gold standard" for the assessment of liver damage in NAFLD being liver biopsy, in recent years, several non-invasive tools have been designed as alternatives to histology, of which fibroscan seems the most promising. Among the different serum markers considered, serum uric acid (SUA) and ferritin have emerged as possible predictors of severity of liver damage in NAFLD. In fact, as widely described in this review, they share common pathogenetic pathways and are both associated with hepatic steatosis and MS, thus suggesting a likely synergistic action. Nevertheless, the power of these serum markers seems to be too low if considered alone, suggesting that they should be included in a wider perspective together with other metabolic and biochemical parameters in order to predict liver damage.

Modulation of Cell Death and Survival by Adipokines in the Liver

Adipokines, hormones predominantly produced from adipose tissue, have been shown to impart dynamic functions in the liver. Emerging evidence has shown that adipokines are also involved in modulating liver cell survival and/or death. Among the various adipokines, adiponectin and leptin directly regulate proliferation of hepatocytes, Kupffer cells, and hepatic stellate cells. Moreover, these adipokines control apoptosis and cell cycle of hepatic cancer cells in a complex manner. Adiponectin possesses both pro- and anti-proliferative properties, whereas leptin appears to play roles as a pro-survival hormone. Recent studies have revealed that regulation of cell death and proliferation is one of the critical factors regulating liver physiology by adipokines. In this review, we summarize the effects of adipokines on apoptosis and survival of liver cells and also demonstrate their implications in regulating various liver functions and decipher the underlying molecular mechanisms.

Elevated serum α-fetoprotein levels in patients with chronic hepatitis C virus genotype 4: not the end of the story

BACKGROUND AND AIM

Elevated serum α-fetoprotein (AFP) is not uncommonly seen among patients with chronic hepatitis C. This study aimed to identify clinical characteristics, histological characteristics, and biochemical markers associated with increased serum AFP levels in hepatitis C virus genotype 4-infected patients with no evidence of hepatocellular carcinoma and to determine the effect of lifestyle modification on these parameters.

METHODS

The study included 447 chronic hepatitis C patients with no evidence of hepatocellular carcinoma and 100 healthy controls. They underwent liver biopsies, homeostasis model assessment-insulin resistance (HOMA-IR), measurement of serum insulin, leptin, adiponectin, tumor necrosis factor-α, and interleukin-6 levels by an enzyme-linked immunosorbent assay, and assessment of AFP levels. Eighty patients with HOMA-IR greater than 3 received prospective longitudinal lifestyle intervention.

RESULTS

In a multivariate analysis, platelet count less than 140×10/cm, a mean platelet volume of at least 9.5 fl, a neutrophil-lymphocyte ratio (NLR) of at least 2, an aspartate transaminase level of at least 55 IU/l, a γ-glutamyl transpeptidase level of at least 40 IU/l, an albumin level of up to 3.8 g/dl, HOMA-IR greater than 3, a leptin level of at least 10 pg/ml, an iron level of at least 165 μg/dl, a ferritin level of at level 175 ng/ml, and hepatic fibrosis F3-F4 were found to be independently associated with elevated AFP levels. The lifestyle intervention significantly improved BMI, platelet indices, NLR, γ-glutamyl transpeptidase, leptin, leptin/adiponectin ratio, tumor necrosis factor-α, interleukin-6, HOMA-IR, and AFP levels.

CONCLUSION

Elevated insulin resistance, leptin, serum iron, ferritin, mean platelet volume, NLR, and advanced fibrosis, as well as decreased platelet count and serum albumin, are independently associated with an elevated AFP level. Lifestyle modification can improve (reduce) insulin resistance, leptin, leptin/adiponectin ratio, platelet count and their indices, NLR, and AFP level.

A "systems medicine" approach to the study of non-alcoholic fatty liver disease

The prevalence of fatty liver (steatosis) in the general population is rapidly increasing worldwide. The progress of knowledge in the physiopathology of fatty liver is based on the systems biology approach to studying the complex interactions among different physiological systems. Similarly, translational and clinical research should address the complex interplay between these systems impacting on fatty liver. The clinical needs drive the applications of systems medicine to re-define clinical phenotypes, assessing the multiple nature of disease susceptibility and progression (e.g. the definition of risk, prognosis, diagnosis criteria, and new endpoints of clinical trials). Based on this premise and in light of recent findings, the complex mechanisms involved in the pathology of fatty liver and their impact on the short- and long-term clinical outcomes of cardiovascular, metabolic liver diseases associated with steatosis are presented in this review using a new "systems medicine" approach. A new data set is proposed for studying the impairments of different physiological systems that have an impact on fatty liver in different subsets of subjects and patients.

Adipose tissue-liver axis in alcoholic liver disease

Alcoholic liver disease (ALD) remains an important health problem worldwide. The disease spectrum is featured by early steatosis, steatohepatitis (steatosis with inflammatory cells infiltration and necrosis), with some individuals ultimately progressing to fibrosis/cirrhosis. Although the disease progression is well characterized, no effective therapies are currently available for the treatment in humans. The mechanisms underlying the initiation and progression of ALD are multifactorial and complex. Emerging evidence supports that adipose tissue dysfunction contributes to the pathogenesis of ALD. In the first part of this review, we discuss the mechanisms whereby chronic alcohol exposure contributed to adipose tissue dysfunction, including cell death, inflammation and insulin resistance. It has been long known that aberrant hepatic methionine metabolism is a major metabolic abnormality induced by chronic alcohol exposure and plays an etiological role in the pathogenesis of ALD. The recent studies in our group documented the similar metabolic effect of chronic alcohol drinking on methionine in adipose tissue. In the second part of this review, we also briefly discuss the recent research progress in the field with a focus on how abnormal methionine metabolism in adipose tissue contributes to adipose tissue dysfunction and liver damage.

Leptin Is Associated With Persistence of Hyperglycemia in Acute Pancreatitis: A Prospective Clinical Study

Adipokines have many homeostatic roles, including modulation of glucose metabolism, but their role in the pathophysiology of hyperglycemia associated with acute and critical illnesses in general, and acute pancreatitis (AP) in particular, is largely unknown. This study aimed to investigate the relationship between a panel of adipokines and hyperglycemia in the early course of AP, as well as the role of adipokines as predictors of AP severity.Adiponectin, leptin, omentin, resistin, and visfatin were measured on a daily basis in the first 72 hours after hospital admission. A first set of analyses was undertaken with admission glycemia stratified by severity, and a second set of analyses was undertaken based on persistence of early hyperglycemia. All of the analyses were adjusted for confounders.A total of 32 patients with AP were included in this study. None of the studied adipokines was significantly associated with glucose level on admission. Leptin was significantly (P = 0.003) increased in patients with persistent hyperglycemia. Adiponectin was significantly associated with the Acute Physiology and Chronic Health Evaluation II (APACHE II) score in patients with persistent hyperglycemia (P = 0.015), visfatin with APACHE II score in patients with persistent hyperglycemia (P = 0.014), and omentin with APACHE II score in all of the patients regardless of the presence or absence of hyperglycemia (P = 0.021).Leptin is significantly associated with persistent hyperglycemia in the early course of AP. Omentin has a potential to become an accurate predictor of AP severity.

Metabolic alterations and hepatitis C: From bench to bedside

In addition to causing cirrhosis and hepatocellular carcinoma, hepatitis C virus (HCV) is thought to cause hypolipidemia, hepatic steatosis, insulin resistance, metabolic syndrome, and diabetes. The viral life cycle of HCV depends on cholesterol metabolism in host cells. HCV core protein and nonstructural protein 5A perturb crucial lipid and glucose pathways, such as the sterol regulatory element-binding protein pathway and the protein kinase B/mammalian target of rapamycin/S6 kinase 1 pathway. Although several lines of transgenic mice expressing core or full HCV proteins exhibit hepatic steatosis and/or dyslipidemia, whether they completely reflect the metabolic alterations in humans with HCV infection remains unknown. Many cross-sectional studies have demonstrated increased prevalences of metabolic alterations and cardiovascular events in patients with chronic hepatitis C (CHC); however, conflicting results exist, primarily due to unavoidable individual variations. Utilizing anti-HCV therapy, most longitudinal cohort studies of CHC patients have demonstrated the favorable effects of viral clearance in attenuating metabolic alterations and cardiovascular risks. To determine the risks of HCV-associated metabolic alterations and associated complications in patients with CHC, it is necessary to adjust for crucial confounders, such as HCV genotype and host baseline glucose metabolism, for a long follow-up period after anti-HCV treatment. Adipose tissue is an important endocrine organ due to its release of adipocytokines, which regulate lipid and glucose metabolism. However, most data on HCV infection and adipocytokine alteration are inconclusive. A comprehensive overview of HCV-associated metabolic and adipocytokine alterations, from bench to bedside, is presented in this topic highlight.

Association of recently described adipokines with liver histology in biopsy-proven non-alcoholic fatty liver disease: a systematic review

The prevalence of non-alcoholic fatty liver disease (NAFLD) is rising, as is the prevalence of obesity and type 2 diabetes. It is increasingly recognized that an impaired pattern in adipokine secretion could play a pivotal role in the development of NAFLD. We performed a systematic review to evaluate the potential link between newly described adipokines and liver histology in biopsy-proven NAFLD patients. A computerized literature search was performed in PubMed, EMBASE and Web of Science electronic databases. Thirty-one cross-sectional studies were included, resulting in a total of seven different investigated adipokines. Studies included in this review mainly had a good methodological quality. Most adipokines were suggested to be involved in the inflammatory response that develops within the context of NAFLD, either at hepatic or systemic level, and/or hepatic insulin resistance. Based on literature, clinical studies suggest that chemerin, resistin and adipocyte-fatty-acid-binding protein potentially are involved in NAFLD pathogenesis and/or progression. However, major inconsistency still exists, and there is a high need for larger studies, together with the need of standardized assays to determine adipokine levels.

Adiponectin: A biomarker for chronic hepatitis C?

Adiponectin, a hormone primarily synthesized and secreted by adipose tissue, plays a pivotal role in lipid metabolism. Chronic hepatitis C (CHC) infection is characterized by disordered lipid metabolism, which may potentially evolve into steatosis over a period of time. A growing body of evidence appears to link decreased adiponectin plasma levels with severe CHC-related steatosis, which suggests a potential role of this adipokine as a diagnostic and therapeutic target for clinical application. In this review, we have attempted to summarize the current status of adiponectin research in the context of CHC, concentrating predominantly on its roles in CHC, and its potential relevance as a biomarker for CHC.

Visceral Obesity Predicts Significant Fibrosis in Patients With Nonalcoholic Fatty Liver Disease

Nonalcoholic fatty liver disease (NAFLD) is associated with visceral obesity. However, the association between visceral adipose tissue (VAT) area and fibrosis in NAFLD patients has not been completely established. This study was aimed to determine the relationship between the computed tomography-measured VAT area and significant fibrosis in NAFLD patients. A total of 324 NAFLD patients and 132 controls were evaluated by liver biopsy. NAFLD was diagnosed based on histological examinations and alcohol consumption <20 g/day. The NAFLD patients showed a higher age and gender-adjusted VAT area than the control group (86.1 ± 2.3 vs 56.7 ± 3.7, P < 0.001). The VAT area increased across the control, NAFLD without significant fibrosis, and NAFLD with significant fibrosis groups (54.9 ± 3.5, 80.6 ± 2.4, and 123.4 ± 6.4, P < 0.001). This association persisted after adjusting for multiple confounders (P for trend = 0.028). A multivariate regression analysis demonstrated the VAT area was independently associated with NAFLD with significant fibrosis (F2-F4) (odds ratio [OR] 1.21 95% confidence interval [CI] 1.07-1.37 per 10 cm(2) increase of VAT area; OR 2.62 [per 1 - standard deviation (SD)] 95% CI 1.41-4.86). Moreover, a multivariate logistic regression analysis revealed the VAT area was independently associated with nonalcoholic steatohepatitis (NASH) in NAFLD (OR 1.17 95% CI 1.05-1.32 per 10 cm increase of VAT area; OR 2.21 [per 1 - SD] 95% CI 1.25-3.89). Increased VAT area is independently associated with NASH or significant fibrosis and VAT might be a central target for lifestyle modifications in NAFLD patients.

The treatment of diabetes mellitus of patients with chronic liver disease

About 80% of patients with liver cirrhosis may have glucose metabolism disorders, 30% show overt diabetes mellitus (DM). Prospective studies have demonstrated that DM is associated with an increased risk of hepatic complications and death in patients with liver cirrhosis. DM might contribute to liver damage by promoting inflammation and fibrosis through an increase in mitochondrial oxidative stress mediated by adipokines. Based on the above mentioned the effective control of hyperglycemia may have a favorable impact on the evolution of these patients. However, only few therapeutic studies have evaluated the effectiveness and safety of antidiabetic drugs and the impact of the treatment of DM on morbidity and mortality in patients with liver cirrhosis. In addition, oral hypoglycemic agents and insulin may produce hypoglycemia and lactic acidosis, as most of these agents are metabolized by the liver. This review discusses the clinical implications of DM in patients with chronic liver disease. In addition the effectiveness and safety of old, but particularly the new antidiabetic drugs will be described based on pharmacokinetic studies and chronic administration to patients. Recent reports regarding the use of the SGLT2 inhibitors as well as the new incretin-based therapies such as injectable glucagon-like peptide-1 (GLP-1) receptor agonists and oral inhibitors of dipeptidylpeptidase-4 (DPP-4) will be discussed. The establishment of clear guidelines for the management of diabetes in patients with CLD is strongly required.

Liver Cancer: Connections with Obesity, Fatty Liver, and Cirrhosis

The burden of hepatocellular carcinoma (HCC), the most common form of liver cancer, is steadily growing because obesity, type 2 diabetes, and nonalcoholic fatty liver disease (NAFLD) are replacing viral- and alcohol-related liver disease as major pathogenic promoters. The most worrisome aspects of these new risk factors are their large spread in the general population and their link with HCC arising in noncirrhotic livers. HCC may be the presenting feature of an asymptomatic nonalcoholic steatohepatitis (NASH), the progressive form of NAFLD. The HCC risk connected to metabolic factors has been underestimated so far, and a poorer surveillance has prevented an adequate treatment. Systemic and hepatic molecular mechanisms involved in obesity- and NAFLD-induced hepatocarcinogenesis as well as potential early markers of HCC are being extensively investigated. This review summarizes current evidence linking obesity, NAFLD and liver cancer, discusses its clinical impact and describes the main mechanisms underlying this complex relationship.

Effect of alcohol on adipose tissue: a review on ethanol mediated adipose tissue injury

BACKGROUND

Alcohol consumption has been in existence in the world for many centuries and it is the major cause of death and injury worldwide. Alcoholic liver disease (ALD) is caused due to excess and chronic alcohol intake. Studies across the globe have identified several pathways leading to ALD. Adipose tissue which has been considered as an energy storage organ is also found to play a major role in ALD progression by secreting hormones and cytokines known as adipokines or adipocytokines. Ethanol affects the metabolic and innate immune activities of adipose tissue contributing to alcohol-induced injury of the tissues.

OBJECTIVE

We aimed at 1) summarizing the metabolism and progression of ALD 2) summarizing about the structure and effect of ethanol induced oxidative stress on adipose tissue 3) reviewing the available data on the effect of ethanol on adipose tissue mass and adipokine secretion in both rodent models and alcoholic patients.

METHODS

The article is summarized based on the original literature and reviews in studying the effect of ethanol on adipose tissue.

RESULTS

Studies on alcoholic patients and rodent models has shown that chronic ethanol consumption reduces adipose tissue mass and causes CYP2E1 mediated oxidative stress and inflammation of adipose tissue. Further hyperlipolysis is observed in adipose tissue that leads to excess fatty acid release that gets transported and deposited in the liver resulting in hepatic steatosis.

CONCLUSION

Studies show that adipose tissue plays a major role in the progression of ALD. So understanding of the mechanisms linking ethanol induced adipose tissue injury with ALD progression would help us in identifying potential therapeutic targets.

SFRP5 hepatic expression is associated with non-alcoholic liver disease in morbidly obese women

BACKGROUND AND AIMS

Secreted frizzled-related protein 5 (SFRP5) was recently described as a new adipokine protective for hepatic steatosis and other obesity-related complications in the mouse model. To date, SFRP5 expression in non-alcoholic fatty liver disease (NAFLD) has not been fully assessed in humans. We measured circulating SFRP5 levels and its expression in liver and adipose tissue, and evaluated its association with NAFLD in morbidly obese women.

MATERIAL AND METHODS

Fifty-four morbidly obese women undergoing bariatric surgery were included in the study. Liver biopsies were used for histology and hepatic triglyceride content quantification. Circulating SFRP5 levels were measured through enzyme-linked immunoabsorbent assay, and SFRP5 expression was performed in hepatic and adipose tissue (subcutaneous and visceral).

RESULTS

Although circulating SFRP5 levels showed a tendency to decrease with NAFLD progression, no significant differences were observed among non-alcoholic steatosis, steatohepatitis, and control subjects. Hepatic SFRP5 expression showed a negative correlation with hepatic triglyceride content (r = -0.349, P = 0.016 for mRNA and r = -0.291, P = 0.040 for SRFP5 protein) and ALT serum levels (r = -0.437, P = 0.001 for SRFP5 protein). In addition, hepatic SFRP5 protein levels were significantly lower in NASH than in control subjects (P = 0.006).

CONCLUSION

This is the first study reporting an association of hepatic SFRP5 expression with NAFLD in humans.

The Cytokinome Profile in Patients with Hepatocellular Carcinoma and Type 2 Diabetes

Understanding the dynamics of the complex interaction network of cytokines, defined as ‘‘cytokinome’’, can be useful to follow progression and evolution of hepatocellular carcinoma (HCC) from its early stages as well as to define therapeutic strategies. Recently we have evaluated the cytokinome profile in patients with type 2 diabetes (T2D) and/or chronic hepatitis C (CHC) infection and/or cirrhosis suggesting specific markers for the different stages of the diseases. Since T2D has been identified as one of the contributory cause of HCC, in this paper we examined the serum levels of cytokines, growth factors, chemokines, as well as of other cancer and diabetes biomarkers in a discovery cohort of patients with T2D, chronic hepatitis C (CHC) and/or CHC-related HCC comparing them with a healthy control group to define a profile of proteins able to characterize these patients, and to recognize the association between diabetes and HCC. The results have evidenced that the serum levels of some proteins are significantly and differently up-regulated in all the patients but they increased still more when HCC develops on the background of T2D. Our results were verified also using a separate validation cohort. Furthermore, significant correlations between clinical and laboratory data characterizing the various stages of this complex disease, have been found. In overall, our results highlighted that a large and simple omics approach, such as that of the cytokinome analysis, supplemented by common biochemical and clinical data, can give a complete picture able to improve the prognosis of the various stages of the disease progression. We have also demonstrated by means of interactomic analysis that our experimental results correlate positively with the general metabolic picture that is emerging in the literature for this complex multifactorial disease.

Stratification of risk of death in severe acute alcoholic hepatitis using a panel of adipokines and cytokines

BACKGROUND

Dysregulated adipose tissue metabolism has been implicated in the pathogenesis of alcoholic liver disease in murine models. We aimed to characterize serum markers of adipose tissue metabolism and inflammation in patients with severe acute alcoholic hepatitis (AAH) and determine their utility to predict survival in severe AAH.

METHODS

A prospective, case-control study design was used. Seventy-six patients hospitalized with severe AAH and 25 ambulatory patients with alcoholic cirrhosis as controls were included. Serum samples were collected for biochemical analyses. Patients were followed for 180 days after enrollment to determine the survival.

RESULTS

AAH patients exhibited higher serum glycerol and free fatty acid levels, suggesting enhanced adipose tissue triglyceride hydrolysis. Patients with AAH demonstrated a distinct serum lipidomic profile compared with alcoholic cirrhosis but not in systemic and adipose-specific insulin resistance. AAH patients had higher serum resistin and plasmin activation inhibitor-1 levels, while serum leptin was decreased. Serum levels of the prolipolytic cytokines tumor necrosis factor-α (TNF-α), interleukin (IL)-6, IL-8, and IL-15 were significantly higher in AAH patients. Only 53% of AAH patients survived 180 days after admission, while all cirrhotic patients were alive at the end of the study period. Among patients with severe AAH, white blood cell count, hemoglobin, resistin, IL-6 and TNF-α were associated with 180-day survival, and all 5 markers demonstrated accuracy by area under receiver-operator curve analysis. Serum IL-6 levels ≥38.66 pg/ml most precisely identified deaths in severe AAH. Patients with IL-6 ≥ 38.66 pg/ml had significantly decreased mean survival compared to those with lower levels.

CONCLUSIONS

AAH patients demonstrate evidence of increased adipose tissue lipolysis and altered serum lipidomic profile compared with alcoholic cirrhosis patients. IL-6 may be a useful biomarker to risk stratify severe AAH patients at the highest risk of mortality.

Herbal SGR Formula Prevents Acute Ethanol-Induced Liver Steatosis via Inhibition of Lipogenesis and Enhancement Fatty Acid Oxidation in Mice

Our previous study indicated that herbal SGR formula partially attenuates ethanol-induced fatty liver, but the underlying mechanisms remain unclear. In the present study, mice were pretreated with SGR (100 and 200 mg/kg/d bw) for 30 d before being exposed to ethanol (4.8 g/kg bw). The biochemical indices and histopathological changes were examined to evaluate the protective effects and to explore potential mechanisms by investigating the adiponectin, tumor necrosis factor-α (TNF-α), peroxisome proliferators-activated receptor-α (PPAR-α), sterol regulatory element binding protein-1c (SREBP-1c), adenosine monophosphate-activated protein kinase (AMPK), and so forth. Results showed that SGR pretreatment markedly inhibited acute ethanol-induced liver steatosis, significantly reduced serum and hepatic triglyceride (TG) level, and improved classic histopathological changes. SGR suppressed the protein expression of hepatic SREBP-1c and TNF-α and increased adiponectin, PPAR-α, and AMPK phosphorylation in the liver. Meanwhile, acute toxicity tests showed that no death or toxic side effects within 14 days were observed upon oral administration of the extracts at a dose of 16 g/kg body wt. These results demonstrate that SGR could protect against acute alcohol-induced liver steatosis without any toxic side effects. Therefore, our studies provide novel molecular insights into the hepatoprotective effect of SGR formula, which may be exploited as a therapeutic agent for ethanol-induced hepatosteatosis.

Insulin resistance in clinical and experimental alcoholic liver disease

Alcoholic liver disease (ALD) is the number one cause of liver failure worldwide; its management costs billions of healthcare dollars annually. Since the advent of the obesity epidemic, insulin resistance (IR) and diabetes have become common clinical findings in patients with ALD; and the development of IR predicts the progression from simple steatosis to cirrhosis in ALD patients. Both clinical and experimental data implicate the impairment of several mediators of insulin signaling in ALD, and experimental data suggest that insulin-sensitizing therapies improve liver histology. This review explores the contribution of impaired insulin signaling in ALD and summarizes the current understanding of the synergistic relationship between alcohol and nutrient excess in promoting hepatic inflammation and disease.

Nonalcoholic fatty liver disease: new treatments

PURPOSE OF REVIEW

Nonalcoholic fatty liver disease is the most common cause of liver dysfunction in the western world because of its close association with obesity, insulin resistance and dyslipidaemia. Nonalcoholic steatohepatitis (NASH) is a particular health concern due to the increased morbidity and mortality associated with progressive disease. At present, without specific targeted pharmacological therapies, the mainstay of therapy remains weight loss through dietary modification and lifestyle change; thus, the purpose of this review is to summarize the recent evidence for current and emerging therapies in NASH.

RECENT FINDINGS

Some existing medications, including pioglitazones and angiotensin receptor antagonists, may be repurposed to help treat this condition. Vitamin E may improve histology in NASH, but safety issues limit its use. Recently, a number of novel agents specifically targeting nonalcoholic fatty liver disease pathogenesis have entered clinical trials, including the farnesoid X receptor agonist obeticholic acid, which has shown significant histological improvements in steatohepatitis and fibrosis.

SUMMARY

Diet/lifestyle modification remains the mainstay of treatment. For patients with NASH and advanced fibrosis, current liver-directed pharmacotherapy with vitamin E and pioglitazone offer some benefits; obeticholic acid appears promising and is currently being tested. Comorbidities must be diagnosed and treated; cardiovascular disease remains a primary cause of death in these patients.

Serum autotaxin is independently associated with hepatic steatosis in women with severe obesity

OBJECTIVE

Autotaxin (ATX) is an adipocyte-derived lysophospholipase that generates the lipid signaling molecule lysophosphatidic acid (LPA). The aim of this study was to determine the relationship between serum ATX and nonalcoholic fatty liver disease (NAFLD) in females with obesity.

METHODS

101 nondiabetic women with obesity (age: 31.5-55.8 years; BMI: 35.0-64.5 kg/m2) were classified as having NAFLD (36.3%) or not having NAFLD (63.7%) based on the degree of hepatic steatosis on abdominal CT. Subjects were characterized for metabolic phenotype including measures of energy, glucose, and lipid homeostasis. Fasting serum adipokines and inflammatory markers were determined by ELISA. Linear regression analysis was used to determine features independently associated with NAFLD.

RESULTS

Subjects with and without NAFLD differed in several key features of metabolic phenotype including BMI, waist circumference, fasting glucose and insulin, HOMA-IR, VLDL, triglycerides, and ALT. Serum adipokines, including ATX and leptin, were higher in subjects with NAFLD. Serum ATX was significantly correlated with alkaline phosphatase, fasting glucose, fasting insulin, and HOMA-IR. Linear regression analysis revealed that serum triglycerides and log-transformed ATX were independently associated with hepatic steatosis.

CONCLUSIONS

Serum ATX may be a potential pathogenic factor and/or biomarker for NAFLD in nondiabetic women with obesity.

Impact of cardiac dysfunction on health-related quality of life in cirrhotic liver transplant candidates

OBJECTIVE

Cardiac dysfunction, in particular left ventricular diastolic dysfunction, is common in cirrhosis. We aimed to investigate the impact of cardiac dysfunction on health-related quality of life (QoL) in liver cirrhosis.

MATERIALS AND METHODS

A total of 88 cirrhotic liver transplant candidates with an available echocardiogram and ECG completed the Short form-36 (SF-36) and Fatigue Impact Scale. In a subgroup of 61 patients, levels of cardiac biomarkers, in particular serum N-terminal pro-brain natriuretic peptide, adiponectin, and high-sensitive troponin T, were also measured.

RESULTS

Although left ventricular systolic diameter was related to a lower SF-36 physical component summary, neither left ventricular diastolic dysfunction nor any other echocardiographic feature was found to be associated with any other SF-36 or Fatigue Impact Scale domain (P>0.05 for all). On linear regression analysis after adjustment for confounders, a prolonged QTc interval was found to be related to a lower SF-36 mental component summary score (β=-9.7, P=0.009) and increased physical fatigue (β=10.5, P=0.004). Neither serum N-terminal pro-brain natriuretic peptide, high-sensitivity troponin T, nor adiponectin levels were found to be related to QoL (P>0.05 for all). Serum adiponectin levels did not differ among patients with versus those without echocardiographic cardiac alterations (P>0.05 for all).

CONCLUSION

A prolonged QTc interval, but not any echocardiographic abnormalities or cardiac biomarkers, seems to be predictive of QoL in cirrhosis.