A Comprehensive Updated Review of Pharmaceutical and Nonpharmaceutical Treatment for NAFLD

Non-invasive evaluation of liver steatosis with imaging modalities: New techniques and applications

In the world, nonalcoholic fatty liver disease (NAFLD) accounts for majority of diffuse hepatic diseases. Notably, substantial liver fat accumulation can trigger and accelerate hepatic fibrosis, thus contributing to disease progression. Moreover, the presence of NAFLD not only puts adverse influences for liver but is also associated with an increased risk of type 2 diabetes and cardiovascular diseases. Therefore, early detection and quantified measurement of hepatic fat content are of great importance. Liver biopsy is currently the most accurate method for the evaluation of hepatic steatosis. However, liver biopsy has several limitations, namely, its invasiveness, sampling error, high cost and moderate intraobserver and interobserver reproducibility. Recently, various quantitative imaging techniques have been developed for the diagnosis and quantified measurement of hepatic fat content, including ultrasound- or magnetic resonance-based methods. These quantitative imaging techniques can provide objective continuous metrics associated with liver fat content and be recorded for comparison when patients receive check-ups to evaluate changes in liver fat content, which is useful for longitudinal follow-up. In this review, we introduce several imaging techniques and describe their diagnostic performance for the diagnosis and quantified measurement of hepatic fat content.

In Vitro Probiotic Properties of Bifidobacterium animalis subsp. lactis SF and Its Alleviating Effect on Non-Alcoholic Fatty Liver Disease

Nonalcoholic fatty liver disease (NAFLD) is a common chronic liver disease with many influencing factors. With the increasing role of the gut–liver axis in various liver diseases, research on the prevention and treatment of NAFLD with probiotics is increasing. In the present study, a Bifidobacterium animalis subsp. strain, B. lactis SF, was isolated from the feces of healthy infants and characterized by sequencing of the 16S rDNA. A systematic probiotic evaluation was carried out, and a diet-induced mouse model was constructed to study the effect and mechanism of B. lactis SF on diet-induced NAFLD. Results show that B. lactis SF has excellent gastrointestinal fluid tolerance and intestinal colonization, and strong antibacterial and antioxidant capabilities. In vivo, B. lactis SF modulated intestinal flora, restored the intestinal barrier, and inhibited LPS entrance into the portal circulation, which subsequently inhibited the TLR4/NF-κB and modulated the PI3K-Akt/AMPK signaling pathway, attenuated the inflammatory response, and reduced lipid accumulation. In addition, B. lactis SF attenuated oxidative stress and further alleviated autophagy, resulting in an ameliorative effect on NAFLD. Therefore, our study provides a new dietary method for the treatment of NAFLD.

Protamine-derived peptide RPR (Arg-Pro-Arg) ameliorates oleic acid-induced lipogenesis via the PepT1 pathway in HepG2 cells

The protamine-derived peptide arginine-proline-arginine (RPR) can ameliorate lifestyle-related diseases such as obesity and hypercholesterolemia. Thus, we hypothesized that the hypolipidemic activity of RPR could attenuate events leading to non-alcoholic fatty liver disease. Addition of 2 m m oleic acid (OA) to the culture medium induced fatty liver conditions in HepG2 cells. The OA + RPR group showed significantly decreased cellular or medium triglyceride (TG) level compared with the OA group. Stearoyl-CoA desaturase-1 (SCD1) or sterol regulatory element-binding protein 1 (SREBP1) protein level was significantly lower in the OA + RPR group than in the OA group. In the R + P + R amino acid mixture-treated group, the TG level was not significantly different from that in the OA-treated group. The OA + RP- or OA + PR-treated groups showed significantly decreased cellular TG level compared with the OA group. Moreover, the effect of RPR disappeared when the peptide transporter 1 (PepT1) was knocked down with a siRNA. Collectively, our results demonstrated that RPR effectively ameliorated hepatic steatosis in HepG2 cells via the PepT1 pathway.

Hepatoprotective Effect of Kaempferol: A Review of the Dietary Sources, Bioavailability, Mechanisms of Action, and Safety

The liver is the body's most critical organ that performs vital functions. Hepatic disorders can affect the physiological and biochemical functions of the body. Hepatic disorder is a condition that describes the damage to cells, tissues, structures, and functions of the liver, which can cause fibrosis and ultimately result in cirrhosis. These diseases include hepatitis, ALD, NAFLD, liver fibrosis, liver cirrhosis, hepatic failure, and HCC. Hepatic diseases are caused by cell membrane rupture, immune response, altered drug metabolism, accumulation of reactive oxygen species, lipid peroxidation, and cell death. Despite the breakthrough in modern medicine, there is no drug that is effective in stimulating the liver function, offering complete protection, and aiding liver cell regeneration. Furthermore, some drugs can create adverse side effects, and natural medicines are carefully selected as new therapeutic strategies for managing liver disease. Kaempferol is a polyphenol contained in many vegetables, fruits, and herbal remedies. We use it to manage various diseases such as diabetes, cardiovascular disorders, and cancers. Kaempferol is a potent antioxidant and has anti-inflammatory effects, which therefore possesses hepatoprotective properties. The previous research has studied the hepatoprotective effect of kaempferol in various hepatotoxicity protocols, including acetaminophen (APAP)-induced hepatotoxicity, ALD, NAFLD, CCl₄, HCC, and lipopolysaccharide (LPS)-induced acute liver injury. Therefore, this report aims to provide a recent brief overview of the literature concerning the hepatoprotective effect of kaempferol and its possible molecular mechanism of action. It also provides the most recent literature on kaempferol's chemical structure, natural source, bioavailability, and safety.

Non-invasive methods for iron overload evaluation in dysmetabolic patients

INTRODUCTION

Although hyperferritinemia may reflect the inflammatory status of patients with non-alcoholic fatty liver disease (NAFLD), approximately 33% of hyperferritinemia cases reflect real hepatic iron overload.

AIM

To evaluate a non-invasive method for assessing mild iron overload in patients with NAFLD using 3T magnetic resonance imaging (MRI) relaxometry, serum hepcidin, and the expression of ferritin subunits.

METHODS

This cross-sectional study assessed patients with biopsy-proven NAFLD. MRI relaxometry was performed using a 3T scanner in all patients, and the results were compared with iron content determined by liver biopsy. Ferritin, hepcidin, and ferritin subunits were assessed and classified according to ferritin levels and to siderosis identified by liver biopsy.

RESULTS

A total of 67 patients with NAFLD were included in the study. MRI revealed mild iron overload in all patients (sensitivity, 73.5%; specificity, 70%). For mild (grade 1) siderosis, the transverse relaxation rate (R₂*) threshold was 58.9 s^-1 and the mean value was 72.5 s^-1 (SD, 33.9), while for grades 2/3 it was 88.2 s^-1 (SD, 31.9) (p < 0.001). The hepcidin threshold for siderosis was > 30.2 ng/mL (sensitivity, 87%; specificity, 82%). Ferritin H and ferritin L subunits were expressed similarly in patients with NAFLD, regardless of siderosis. There were no significant differences in laboratory test results between the groups, including glucose parameters and liver function tests.

CONCLUSIONS

MRI relaxometry and serum hepcidin accurately assessed mild iron overload in patients with dysmetabolic iron overload syndrome.

Effects of Dietary Nutrients on Fatty Liver Disease Associated With Metabolic Dysfunction (MAFLD): Based on the Intestinal-Hepatic Axis

Non-alcoholic fatty liver disease (NAFLD) has recently become the most common liver disease with a global prevalence of over 25% and is expected to increase. Recently, experts have reached a consensus that “fatty liver disease associated with metabolic dysfunction or MAFLD” may be a more appropriate and inclusive definition than NAFLD. Like the former name NAFLD, MAFLD, as a manifestation of multiple system metabolic disorders involving the liver, has certain heterogeneity in its pathogenesis, clinical manifestations, pathological changes and natural outcomes. We found that there is a delicate dynamic balance among intestinal microflora, metabolites and host immune system to maintain a healthy intestinal environment and host health. On the contrary, this imbalance is related to diseases such as MAFLD. However, there are no clear studies on how dietary nutrients affect the intestinal environment and participate in the pathogenesis of MAFLD. This review summarizes the interactions among dietary nutrients, intestinal microbiota and MAFLD in an attempt to provide evidence for the use of dietary supplements to regulate liver function in patients with MAFLD. These dietary nutrients influence the development and progression of MAFLD mainly through the hepatic-intestinal axis by altering dietary energy absorption, regulating bile acid metabolism, changing intestinal permeability and producing ethanol. Meanwhile, the nutrients have the ability to combat MAFLD in terms of enriching abundance of intestinal microbiota, reducing Firmicutes/Bacteroidetes ratio and promoting abundance of beneficial gut microbes. Therefore, family therapy with MAFLD using a reasonable diet could be considered.

Decreased Serum zinc, selenium, and vitamin E as possible risk factors of hepatic fibrosis in non-alcoholic fatty liver disease

BACKGROUNDS

The incidence of non-alcoholic fatty liver disease (NAFLD) has been significantly growing in recent years. Although the pathophysiology of fibrosis progression in NAFLD is not yet known, oxidative stress and inflammation have been known to have a major role in the development of NASH. Understanding the impact of micronutrients in NAFLD could potentially help us better understand NAFLD pathogenesis.

AIMS

Assessing the serum levels of Zn, Se, and Vitamin E and their relation to the development of hepatic fibrosis in NAFLD patients.

METHODS

This study included 80 NAFLD patients and 40 healthy controls. All of the patients were subjected to abdominal ultrasound and FibroScan examination (to estimate hepatic fibrosis and steatosis degree), and the serum levels of Zn, Se, and vitamin E were evaluated.

RESULTS

A statistically significant difference in the serum levels of Zn and Se was observed between the NAFLD group and the control group (P-value = 0.04 and 0.05, respectively). The serum levels of Zn and Se were independently related to the presence of hepatic fibrosis in NAFLD. However, serum vitamin E was not related to the severity of NAFLD. Furthermore, no significant difference in the levels of Zn, Se, and vitamin E was observed between the different groups of NAFLD patients categorized according to the degree of steatosis and the control group.

CONCLUSIONS

Reduced serum levels of Zn and Se can be considered a possible risk factor for hepatic fibrosis in NAFLD. Deficiency in these micronutrients could play a role in the pathogenesis of NAFLD.

Knowledge of liver fibrosis stage among adults with NAFLD/NASH improves adherence to lifestyle changes

BACKGROUND & AIMS

Though lifestyle interventions can reverse disease progression in people with non-alcoholic fatty liver disease/non-alcoholic steatohepatitis (NAFLD/NASH), unawareness about disease severity might compromise behavioural changes. Data from this first international cross-sectional survey of individuals with NAFLD/NASH were used to identify correlates of both unawareness about fibrosis stage and its association with adherence to lifestyle adjustments.

METHODS

Adults with NAFLD/NASH registered on the platform Carenity were invited to participate in an online 20-min, six-section survey in Canada, France, Germany, Italy, Spain and the United Kingdom to describe their experience with NAFLD/NASH and its care (N = 1411). Weighted binary and multinomial logistic regressions were performed to estimate the effect of explanatory variables on unawareness of fibrosis stage and poor adherence to lifestyle changes respectively.

RESULTS

In the study group, 15.5% had obesity and 59.2% did not know their fibrosis stage. After multiple adjustments, individuals with a body mass index (BMI) ≥35 were over twice as likely to not know their fibrosis stage. People with a BMI >30 had a threefold higher risk of having poor adherence to lifestyle changes. Unawareness about fibrosis stage was also significantly associated with poor adherence to lifestyle adjustments.

CONCLUSIONS

As fibrosis stage is becoming the main predictor of NAFLD progression, improving patient-provider communication-especially for people with obesity-about liver fibrosis stage, its associated risks and how to mitigate them, is needed. Training for healthcare professionals and promoting patient educational programmes to support behaviour changes should also be included in the liver health agenda.

Breathing new life into clinical testing and diagnostics: perspectives on volatile biomarkers from breath

Human breath offers several benefits for diagnostic applications, including simple, noninvasive collection. Breath is a rich source of clinically-relevant biological information; this includes a volatile fraction, where greater than 1,000 volatile organic compounds (VOCs) have been described so far, and breath aerosols that carry nucleic acids, proteins, signaling molecules, and pathogens. Many of these factors, especially VOCs, are delivered to the lung by the systemic circulation, and diffusion of candidate biomarkers from blood into breath allows systematic profiling of organismal health. Biomarkers on breath offer the capability to advance early detection and precision medicine in areas of global clinical need. Breath tests are noninvasive and can be performed at home or in a primary care setting, which makes them well-suited for the kind of public screening program that could dramatically improve the early detection of conditions such as lung cancer. Since measurements of VOCs on breath largely report on metabolic changes, this too aids in the early detection of a broader range of illnesses and can be used to detect metabolic shifts that could be targeted through precision medicine. Furthermore, the ability to perform frequent sampling has envisioned applications in monitoring treatment responses. Breath has been investigated in respiratory, liver, gut, and neurological diseases and in contexts as diverse as infectious diseases and cancer. Preclinical research studies using breath have been ongoing for some time, yet only a few breath-based diagnostics tests are currently available and in widespread clinical use. Most recently, tests assessing the gut microbiome using hydrogen and methane on breath, in addition to tests using urea to detect Helicobacter pylori infections have been released, yet there are many more applications of breath tests still to be realized. Here, we discuss the strengths of breath as a clinical sampling matrix and the technical challenges to be addressed in developing it for clinical use. Historically, a lack of standardized methodologies has delayed the discovery and validation of biomarker candidates, resulting in a proliferation of early-stage pilot studies. We will explore how advancements in breath collection and analysis are in the process of driving renewed progress in the field, particularly in the context of gastrointestinal and chronic liver disease. Finally, we will provide a forward-looking outlook for developing the next generation of clinically relevant breath tests and how they may emerge into clinical practice.

Redefining non-alcoholic fatty liver disease to metabolic associated fatty liver disease: Is this plausible?

Recently, a single letter change has taken the world by storm. A group of experts have developed a consensus to upgrade the term non-alcoholic fatty liver disease (NAFLD) to metabolic associated fatty liver disease (MAFLD), suggesting that MAFLD would more accurately reflect not only the disease pathogenesis but would also help in patient stratification for management with NAFLD. However, the difference of opinion exists, which has made the NAFLD vs MAFLD debate the current talk of the town. This review will focus on the plausibility and implications of redefining NAFLD as MAFLD.

Quantitative Evaluation of Hepatic Steatosis Using Advanced Imaging Techniques: Focusing on New Quantitative Ultrasound Techniques

Nonalcoholic fatty liver disease, characterized by excessive accumulation of fat in the liver, is the most common chronic liver disease worldwide. The current standard for the detection of hepatic steatosis is liver biopsy; however, it is limited by invasiveness and sampling errors. Accordingly, MR spectroscopy and proton density fat fraction obtained with MRI have been accepted as non-invasive modalities for quantifying hepatic steatosis. Recently, various quantitative ultrasonography techniques have been developed and validated for the quantification of hepatic steatosis. These techniques measure various acoustic parameters, including attenuation coefficient, backscatter coefficient and speckle statistics, speed of sound, and shear wave elastography metrics. In this article, we introduce several representative quantitative ultrasonography techniques and their diagnostic value for the detection of hepatic steatosis.

Lactobacillus lactis and Pediococcus pentosaceus-driven reprogramming of gut microbiome and metabolome ameliorates the progression of non-alcoholic fatty liver disease

BACKGROUND

Although microbioa-based therapies have shown putative effects on the treatment of non-alcoholic fatty liver disease (NAFLD), it is not clear how microbiota-derived metabolites contribute to the prevention of NAFLD. We explored the metabolomic signature of Lactobacillus lactis and Pediococcus pentosaceus in NAFLD mice and its association in NAFLD patients.

METHODS

We used Western diet-induced NAFLD mice, and L. lactis and P. pentosaceus were administered to animals in the drinking water at a concentration of 109 CFU/g for 8 weeks. NAFLD severity was determined based on liver/body weight, pathology and biochemistry markers. Caecal samples were collected for the metagenomics by 16S rRNA sequencing. Metabolite profiles were obtained from caecum, liver and serum. Human stool samples (healthy control [n = 22] and NAFLD patients [n = 23]) were collected to investigate clinical reproducibility for microbiota-derived metabolites signature and metabolomics biomarker.

RESULTS

L. lactis and P. pentosaceus supplementation effectively normalized weight ratio, NAFLD activity score, biochemical markers, cytokines and gut-tight junction. While faecal microbiota varied according to the different treatments, key metabolic features including short chain fatty acids (SCFAs), bile acids (BAs) and tryptophan metabolites were analogously restored by both probiotic supplementations. The protective effects of indole compounds were validated with in vitro and in vivo models, including anti-inflammatory effects. The metabolomic signatures were replicated in NAFLD patients, accompanied by the comparable levels of Firmicutes/Bacteroidetes ratio, which was significantly higher (4.3) compared with control (0.6). Besides, the consequent biomarker panel with six stool metabolites (indole, BAs, and SCFAs) showed 0.922 (area under the curve) in the diagnosis of NAFLD.

CONCLUSIONS

NAFLD progression was robustly associated with metabolic dys-regulations in the SCFAs, bile acid and indole compounds, and NAFLD can be accurately diagnosed using the metabolites. L. lactis and P. pentosaceus ameliorate NAFLD progression by modulating gut metagenomic and metabolic environment, particularly tryptophan pathway, of the gut-liver axis.

Hepatic protective effects of Shenling Baizhu powder, a herbal compound, against inflammatory damage via TLR4/NLRP3 signalling pathway in rats with nonalcoholic fatty liver disease

OBJECTIVE

High-fat diet (HFD) and inflammation are two key contributors to nonalcoholic fatty liver disease (NAFLD). Shenling Baizhu powder (SLBZP), a classical herbal compound, has been successfully used to alleviate NAFLD. However, its specific mechanisms are not fully understood. In this study, we assessed the anti-NAFLD effect of SLBZP in vivo.

METHODS

Rats were fed an HFD with or without SLBZP or with probiotics. At the end of week 16, an echo magnetic resonance imaging (EchoMRI) body composition analyser was used to quantitatively analyse body composition; a micro-computed tomography (micro-CT) imaging system was used to evaluate whole body and liver fat; and the Moor full-field laser perfusion imager 2 was used to assess liver microcirculation, after which, all rats were sacrificed. Then, biochemical indicators in the blood and the ultrastructure of rat livers were evaluated. Protein expression related to the liver Toll-like receptor 4 (TLR4)/Nod-like receptor family pyrin domain-containing 3 (NLRP3) signalling pathway was assessed using Western blot analysis. Further, high-throughput screening of 29 related inflammatory factors in liver tissue was performed using a cytokine array.

RESULTS

SLBZP supplementation reduced body weight, serum free fatty acid, and insulin resistance index (P < 0.05). It also ameliorated liver microcirculation and ultrastructural abnormalities. EchoMRI and micro-CT quantitative analyses showed that treatment with SLBZP reduced fat mass and visceral fat (P < 0.05 and P < 0.01, respectively). In addition, SLBZP decreased the expression of lipopolysaccharide (LPS)-activated TLR4/NLRP3 signalling pathway-related proteins and altered the expression levels of some inflammatory cytokines in liver tissues.

CONCLUSION

SLBZP can inhibit NLRP3 inflammasome activation and interleukin-1β release by suppressing LPS-induced TLR4 expression in rats with HFD-induced NAFLD. Thus, SLBZP may be beneficial for the prevention and treatment of inflammatory damage and associated diseases.

Multifactorial Basis and Therapeutic Strategies in Metabolism-Related Diseases

Throughout the 20th and 21st centuries, the incidence of non-communicable diseases (NCDs), also known as chronic diseases, has been increasing worldwide. Changes in dietary and physical activity patterns, along with genetic conditions, are the main factors that modulate the metabolism of individuals, leading to the development of NCDs. Obesity, diabetes, metabolic associated fatty liver disease (MAFLD), and cardiovascular diseases (CVDs) are classified in this group of chronic diseases. Therefore, understanding the underlying molecular mechanisms of these diseases leads us to develop more accurate and effective treatments to reduce or mitigate their prevalence in the population. Given the global relevance of NCDs and ongoing research progress, this article reviews the current understanding about NCDs and their related risk factors, with a focus on obesity, diabetes, MAFLD, and CVDs, summarizing the knowledge about their pathophysiology and highlighting the currently available and emerging therapeutic strategies, especially pharmacological interventions. All of these diseases play an important role in the contamination by the SARS-CoV-2 virus, as well as in the progression and severity of the symptoms of the coronavirus disease 2019 (COVID-19). Therefore, we briefly explore the relationship between NCDs and COVID-19.

Adult human liver slice cultures: Modelling of liver fibrosis and evaluation of new anti-fibrotic drugs

BACKGROUND

Liver fibrosis can result in end-stage liver failure and death.

AIM

To examine human liver fibrogenesis and anti-fibrotic therapies, we evaluated the three dimensional ex vivo liver slice (LS) model.

METHODS

Fibrotic liver samples (F0 to F4 fibrosis stage according to the METAVIR score) were collected from patients after liver resection. Human liver slices (HLS) were cultivated for up to 21 days. Hepatitis C virus (HCV) infection, alcohol (ethanol stimulation) and steatosis (palmitate stimulation) were examined in fibrotic (F2 to F4) liver slices infected (or not) with HCV. F0-F1 HLS were used as controls. At day 0, either ursodeoxycholic acid (choleretic and hepatoprotective properties) and/or α-tocopherol (antioxidant properties) were added to standard of care on HLS and fibrotic liver slices, infected (or not) with HCV. Expression of the biomarkers of fibrosis and the triglyceride production were checked by quantitative reverse transcription polymerase chain reaction and/or enzyme-linked immunosorbent assay.

RESULTS

The cultures were viable in vitro for 21 days allowing to study fibrosis inducers and to estimate the effect of anti-fibrotic drugs. Expression of the biomarkers of fibrosis and the progression to steatosis (estimated by triglycerides production) was increased with the addition of HCV and /or ethanol or palmitate. From day 15 of the follow-up studies, a significant decrease of both transforming growth factor β-1 and Procol1A1 expression and triglycerides production was observed when a combined anti-fibrotic treatment was applied on HCV infected F2-F4 LS cultures.

CONCLUSION

These results show that the human three dimensional ex vivo model effectively reflects the in vivo processes in damaged human liver (viral, alcoholic, nonalcoholic steatohepatitis liver diseases) and provides the proof of concept that the LS examined model permits a rapid evaluation of new anti-fibrotic therapies when used alone or in combination.

miR-122-5p/KIF5B/AMPK/AKT regulatory network regulates the progression of NAFLD

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) is a progressive liver disease, which may develop into end-stage liver disease and endanger human life. miR-122-5p may be related to the progression of NAFLD disease, but the specific regulation mechanism is still unknown. It is helpful for us to optimize the prevention or treatment strategy of NAFLD.

METHODS

Real-time PCR was applied to test miR-122-5p and KIF5B in serum, rat liver tissue induced by high fat diet (HFD), and primary hepatocytes exposed to oleic acid ester and palmitate (FFA) of NAFLD patients. The role of miR-122-5p on inflammatory factors (MCP-1, TNF-α, IL-10) and liver injury markers (AST, ALT) in vivo and in vitro was analyzed.

RESULTS

miR-122-5p and KIF5B were both highly expressed in NAFLD patients' serum, rat liver tissue and primary hepatocytes, while KIF5B was low expressed. miR-122-5p expression enhanced with the increase of HFD feeding time. The dual luciferase reporter gene assay system confirmed that there was a targeting relationship between miR-122-5p and KIF5B, indicating that KIF5B and protein level were evidently up-regulated in primary hepatocytes. Down-regulation of miR-122-5p was helpful to improve the liver weight/body weight ratio (liver index) level of rats, as well as the levels of triglyceride (TG), inflammatory factors and liver injury markers in liver tissues in vivo and in vitro. Phosphorylation of AMPK/AKT pathway-related proteins and fat metabolism-related factors in rat liver tissues and cells in primary hepatocytes were notably reduced, while down-regulation of miR-122-5p was helpful to restore activation of the pathway and increase the level of fat metabolism-related factors.

CONCLUSION

Decrease of miR-122-5p can target and enhance KIF5B, which can be applied for treating NAFLD.

Dietary approaches to managing nonalcoholic fatty liver disease

ABSTRACT

Nonalcoholic fatty liver disease (NAFLD), a multisystem, prevalent liver disease, can be managed with lifestyle interventions, including diet, given the lack of well-established pharmacologic therapies. This review explores the different dietary approaches that have been found effective in the management of NAFLD, offering a unique resource to healthcare professionals.

Effect of dietary carbohydrate and lipid modification on clinical and anthropometric parameters in nonalcoholic fatty liver disease: a systematic review and meta-analysis

CONTEXT

Nonalcoholic fatty liver disease (NAFLD) is estimated to affect approximately 25% of the adult population, making it one of the most common chronic liver diseases worldwide and a major public health problem. Still, there is no consensus on the most appropriate nutritional intervention for disease treatment.

OBJECTIVE

To systematize and synthesize the results of randomized controlled trials that have evaluated the effect of dietary interventions with different, quantitative, macronutrient compositions on hepatic steatosis attenuation, serum levels of alanine aminotransferase, aspartate aminotransferase, lipid profile, glucose metabolism markers, and anthropometric parameters of adults and the elderly (age ≥ 60 years) with NAFLD.

DATA SOURCES

MEDLINE databases via PubMed, Embase, Science Direct, LILACS, Web of Science, ClinicalTrials.gov, and Cochrane Library were searched. Randomized controlled trials that compared interventions as diets with values ≤ 45% or 20% of the total daily energy intake from carbohydrates or lipids, respectively, compared with dietary reference intakes, were included.

DATA EXTRACTION

Risk of bias was assessed through the Cochrane Collaboration tool. The meta-analysis was only performed to evaluate the effect of carbohydrate-modified diets on the outcome variables. The number of participants and mean values and respective standard deviations of the outcome variables were extracted and used to calculate weighted mean differences and their respective 95%CIs.

RESULTS

The search strategy resulted in 21 146 studies, of which 10 were retained for qualitative analysis and 6 were included in the meta-analysis. From the analysis of 10 studies were identified 8 articles in which low-calorie diets were evaluated and 3 interventions that used an isocaloric diet. Only 3 studies were classified as having low risk of bias.

CONCLUSION

The observed effects on hepatic steatosis, serum alanine aminotransferase and aspartate aminotransferase levels, parameters of lipid and glucose metabolism, and anthropometric variables were mostly related to a hypocaloric diet. The use of reduced macronutrient interventions had no efficacy.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO registration no. CRD42018088824.

Hydrogen inhalation alleviates nonalcoholic fatty liver disease in metabolic syndrome rats

Hydrogen exhibits therapeutic and preventive effects against various diseases. The present study investigated the potential protective effect and dose-dependent manner of hydrogen inhalation on high fat and fructose diet (HFFD)-induced nonalcoholic fatty liver disease (NAFLD) in Sprague-Dawley rats. Rats were randomly divided into four groups: i) Control group, regular diet/air inhalation; ii) model group, HFFD/air inhalation; iii) low hydrogen group, HFFD/4% hydrogen inhalation; and iv) high hydrogen group, HFFD/67% hydrogen inhalation. After a 10-week experiment, hydrogen inhalation ameliorated weight gain, abdominal fat index, liver index and body mass index of rats fed with HFFD and lowered the total area under the curve in an oral glucose tolerance test. Hydrogen inhalation also ameliorated the increase in liver lipid content and alanine transaminase and aspartate transaminase activities. Liver histopathologic changes evaluated with hematoxylin and eosin as well as Oil Red O staining revealed lower lipid deposition in hydrogen inhalation groups, consistent with the decrease in the expression of the lipid synthesis gene SREBP-1c. The majority of the indicators were affected following treatment with hydrogen in a dose-dependent manner. In conclusion, hydrogen inhalation may play a protective role by influencing the general state, lipid metabolism parameters, liver histology and liver function indicators in the rat model of metabolic syndrome with NAFLD.

Silymarin as Supportive Treatment in Liver Diseases: A Narrative Review

Silymarin, an extract from milk thistle seeds, has been used for centuries to treat hepatic conditions. Preclinical data indicate that silymarin can reduce oxidative stress and consequent cytotoxicity, thereby protecting intact liver cells or cells not yet irreversibly damaged. Eurosil 85® is a proprietary formulation developed to maximize the oral bioavailability of silymarin. Most of the clinical research on silymarin has used this formulation. Silymarin acts as a free radical scavenger and modulates enzymes associated with the development of cellular damage, fibrosis and cirrhosis. These hepatoprotective effects were observed in clinical studies in patients with alcoholic or non-alcoholic fatty liver disease, including patients with cirrhosis. In a pooled analysis of trials in patients with cirrhosis, silymarin treatment was associated with a significant reduction in liver-related deaths. Moreover, in patients with diabetes and alcoholic cirrhosis, silymarin was also able to improve glycemic parameters. Patients with drug-induced liver injuries were also successfully treated with silymarin. Silymarin is generally very well tolerated, with a low incidence of adverse events and no treatment-related serious adverse events or deaths reported in clinical trials. For maximum benefit, treatment with silymarin should be initiated as early as possible in patients with fatty liver disease and other distinct liver disease manifestations such as acute liver failure, when the regenerative potential of the liver is still high and when removal of oxidative stress, the cause of cytotoxicity, can achieve the best results.

Efficacy of a 2-Month Very Low-Calorie Ketogenic Diet (VLCKD) Compared to a Standard Low-Calorie Diet in Reducing Visceral and Liver Fat Accumulation in Patients With Obesity

Background: Currently the treatment of non-alcoholic fatty liver disease (NAFLD) is based on weight loss through lifestyle changes, such as exercise combined with calorie-restricted dieting. Objectives: To assess the effects of a commercially available weight loss program based on a very low-calorie ketogenic diet (VLCKD) on visceral adipose tissue (VAT) and liver fat content compared to a standard low-calorie (LC) diet. As a secondary aim, we evaluated the effect on liver stiffness measurements. Methods: Open, randomized controlled, prospective pilot study. Patients were randomized and treated either with an LC or a VLCKD and received orientation and encouragement to physical activity equally for both groups. VAT, liver fat fraction, and liver stiffness were measured at baseline and after 2 months of treatment using magnetic resonance imaging. Paired t-tests were used for comparison of continuous variables between visits and unpaired test between groups. Categorical variables were compared using the χ²-test. Pearson correlation was used to assess the association between VAT, anthropometric measures, and hepatic fat fraction. A significance level of the results was established at p < 0.05. Results: Thirty-nine patients (20 with VLCKD and 19 with LC) were evaluated at baseline and 2 months of intervention. Relative weight loss at 2 months was -9.59 ± 2.87% in the VLCKD group and -1.87 ± 2.4% in the LC group (p < 0.001). Mean reductions in VAT were -32.0 cm² for VLCKD group and -12.58 cm² for LC group (p < 0.05). Reductions in liver fat fraction were significantly more pronounced in the VLCKD group than in the LC group (4.77 vs. 0.79%; p < 0.005). Conclusion: Patients undergoing a VLCKD achieved superior weight loss, with significant VAT and liver fat fraction reductions when compared to the standard LC diet. The weight loss and rapid mobilization of liver fat demonstrated with VLCKD could serve as an effective alternative for the treatment of NAFLD. Clinical Trial Registration: ClinicalTrials.gov, identifier: NCT04322110.

Systematic Review with Meta-Analysis: The Effects of Probiotics in Nonalcoholic Fatty Liver Disease

Background and Aims

Probiotics was considered as a potential therapy for nonalcoholic fatty liver disease (NAFLD) without approval and comprehensive assessment in recent years, which call for a meta-analysis.

Methods

We performed electronic and manual searches including English and Chinese databases published before April 2019, with the use of mesh term and free text of "nonalcoholic fatty liver disease" and "probiotics." Clinical trials evaluating the efficacy of probiotic therapy in NAFLD patients were included according to the eligibility criteria. With the use of random effects models, clinical outcomes were presented as weighted mean difference (WMD) with 95% confidence interval (CI), while heterogeneity and meta-regression were also assessed.

Results

28 clinical trials enrolling 1555 criterion proven NAFLD patients with the use of probiotics from 4 to 28 weeks were included. Overall, probiotic therapy had beneficial effects on body mass index (WMD: -1.46, 95% CI: [-2.44, -0.48]), alanine aminotransferase (WMD: -13.40, 95% CI: [-17.03, -9.77]), aspartate transaminase (WMD: -13.54, 95% CI: [-17.86, -9.22]), gamma-glutamyl transpeptidase (WMD: -9.88, 95% CI: [-17.77, -1.99]), insulin (WMD: -1.32, 95% CI: [-2.43, -0.21]), homeostasis model assessment-insulin resistance (WMD: -0.42, 95% CI: [-0.73, -0.12]), and total cholesterol (WMD: -15.38, 95% CI: [-26.50, -4.25]), but not in fasting blood sugar, lipid profiles, or tumor necrosis factor-alpha.

Conclusion

The systematic review and meta-analysis support that probiotics are superior to placebo in NAFLD patients and could be utilized as a common complementary therapeutic approach.

Effect of Lactobacillus paracasei N1115 and fructooligosaccharides in nonalcoholic fatty liver disease

INTRODUCTION

Nonalcoholic fatty liver disease (NAFLD) is a growing health concern worldwide. Administration of probiotics and prebiotics has been proposed as a convenient and effective treatment. Our study aims to evaluate the therapeutic benefits of Lactobacillus paracasei N1115 (N1115) and fructooligosaccharides (FOS) by examining the histopathogenesis and underlying molecular events of NAFLD.

MATERIAL AND METHODS

An NAFLD mouse model was established by feeding C57BL/6 mice with a high-fat diet (HFD). N1115, FOS and synbiotics were administered for 16 weeks.

RESULTS

N1115, FOS and synbiotics alleviated HFD-induced hepatic steato-sis and release of tumor necrosis factor-α, and slowed the progression of cirrhosis. Compared to the HFD group, these dietary supplements reduced serum total triglyceride and cholesterol, and appeared to decrease the fasting blood glucose and insulin. Intraperitoneal glucose tolerance tests, homeostatic model assessment of insulin resistance and real-time PCR showed that the regimens could overcome insulin resistance. These findings were associated with the transcriptional repression of inflammatory factors such as lipopolysaccharides, Toll-like receptor 4 and nuclear factor-κB. Lastly, N1115, FOS, and synbiotics improved the intestinal barrier functions and histologic integrity. This was accompanied by the restoration of the p38 MAPK pathway and in-creased expression of the tight junction components occludin-1 and claudin-1.

CONCLUSIONS

N1115, FOS and synbiotics are effective in the prevention and treatment of NAFLD. Our data support the translation of these agents into clinical evaluation in human subjects with NAFLD and/or associated risk factors.

Prevalence, incidence, and outcome of non-alcoholic fatty liver disease in Asia, 1999-2019: a systematic review and meta-analysis

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) is the most prevalent chronic liver disease worldwide. Asia is a large, heterogeneous area with substantial variation in socioeconomic status and prevalence of obesity. We estimated the prevalence, incidence, and outcomes of NAFLD in the Asian population to assist stakeholders in understanding NAFLD disease burden.

METHODS

We searched PubMed, EMBASE, and the Cochrane Library from database inception to Jan 17, 2019, for studies reporting NAFLD prevalence, incidence, or outcome in Asia. We included only cross-sectional and longitudinal observational studies of patients with NAFLD diagnosed by imaging, serum-based indices, or liver biopsy. Studies that included patients with overlapping liver disease or that did not screen for excess alcohol consumption were excluded. Two investigators independently screened and extracted data. The main outcomes were pooled NAFLD prevalence, incidence, and hepatocellular carcinoma incidence and overall mortality in patients with NAFLD. Summary estimates were calculated using a random-effects model. This study is registered with PROSPERO, number CRD42018088468.

FINDINGS

Of 4995 records identified, 237 studies (13 044 518 participants) were included for analysis. The overall prevalence of NAFLD regardless of diagnostic method was 29·62% (95% CI 28·13-31·15). NAFLD prevalence increased significantly over time (25·28% [22·42-28·37] between 1999 and 2005, 28·46% [26·70-30·29] between 2006 and 2011, and 33·90% [31·74-36·12] between 2012 and 2017; p<0·0001). The pooled annual NAFLD incidence rate was 50·9 cases per 1000 person-years (95% CI 44·8-57·4). In patients with NAFLD, the annual incidence of hepatocellular carcinoma was 1·8 cases per 1000 person-years (0·8-3·1) and overall mortality rate was 5·3 deaths per 1000 person-years (1·5-11·4).

INTERPRETATION

NAFLD prevalence in Asia is increasing and is associated with poor outcomes including hepatocellular carcinoma and death. Targeted public health strategies must be developed in Asia to target the drivers of this rising epidemic and its associated complications, especially in high-risk groups, such as older obese men.

FUNDING

None.

Clinical workup of fatty liver for the primary care provider

Nonalcoholic fatty liver disease (NAFLD) is quickly emerging as a global epidemic in parallel with the rise in obesity and the Metabolic Syndrome. NAFLD, once seen simply as a passive consequence of the Metabolic Syndrome (MetS), has been found to interact with other features of MetS to exacerbate insulin resistance, diabetes, and cardiovascular disease. NAFLD is also becoming the top indication for liver transplant and an important risk factor for hepatocellular carcinoma. Treatment of this disorder is limited mainly to lifestyle modifications to promote weight loss along with consideration for off-label use of certain medications, but recent progression in clinical trials means more effective treatments are on the horizon. Therefore, the primary care provider must be prepared to recognize and determine the severity of this disorder in order to optimize management. In this review, we will discuss risk factors for NAFLD, workup and differential, and finally, offer recommendations on screening.

The Adenosine Monophosphate (AMP) Analog, 5-Aminoimidazole-4-Carboxamide Ribonucleotide (AICAR) Inhibits Hepatosteatosis and Liver Tumorigenesis in a High-Fat Diet Murine Model Treated with Diethylnitrosamine (DEN)

Background

The development and progression of hepatocellular carcinoma (HCC) are associated with obesity and hepatosteatosis. AMP-activated protein kinase (AMPK) regulates metabolic homeostasis. This study aimed to investigate the effects of treatment with the adenosine monophosphate (AMP) analog, 5-aminoimidazole-4-carboxamide ribonucleotide (AICAR) on hepatosteatosis in a mouse model fed a high-fat diet (HFD), and on hepatocellular carcinoma (HCC) induced by diethylnitrosamine (DEN) in the HFD mouse model.

Material/Methods

Male C57BL/6 male mice from two weeks of age were fed a high-fat diet, resulting in hepatosteatosis. HFD mice (15–20 per group) were treated with AICAR and without AICAR. HFD mice were treated with DEN, with and without AICAR. Mouse liver tissues were examined histologically using lipid histochemical stains, immunohistochemistry, and immunofluorescence. Levels of cytokines, alanine transaminase (ALT), triacylglyceride (TAG), and apoptosis were determined. Western blot was used to detect AMPK, pAMPK, STAT3, and pSTAT3. Real-time polymerase chain reaction (RT-PCR) detected expression of the ACL, FAS, CD36, ATGL, CPT1, and IL6 genes.

Results

In the HFD mouse model, AICAR treatment inhibited hepatic lipid synthesis and IL-6 expression. In the DEN-treated mice, AICAR treatment reduced tumorigenesis, IL-6 signaling, and STAT3 activation. Short-term AICAR treatment had no significant effect in advanced HCC.

Conclusions

In an HFD mouse model, treatment with AICAR reduced the development of hepatosteatosis, and following treatment with the liver carcinogen, DEN, AICAR reduced the development of HCC. These preliminary findings support further studies on the role of AICAR in fatty liver disease and HCC.

Modulation of gut microbiome in nonalcoholic fatty liver disease: pro-, pre-, syn-, and antibiotics

Nonalcoholic fatty liver disease (NAFLD) is one of the most common types of liver diseases worldwide and its incidence continues to increase. NAFLD occurs when the body can no longer effectively store excess energy in the adipose tissue. Despite the increasing prevalence of NAFLD, making lifestyle changes, including increased exercise, is often an elusive goal for patients with NAFLD. The liver directly connects to the gut-gastrointestinal milieu via the portal vein, which are all part of the gut-liver axis. Therefore, the gut-microbiome and microbial products have been actively studied as likely key factors in NAFLD pathophysiology. Hence, dysbiosis of the gut microbiome and therapeutic manipulation of the gut-liver axis are being investigated. Novel therapeutic approaches for modulating gut microbiota through the administration of probiotics, prebiotics, synbiotics, and antibiotics have been proposed with numerous promising initial reports on the effectiveness and clinical applications of these approaches. This review delves into the current evidence on novel therapies that modulate gut microbiota and discusses ongoing clinical trials targeting the gut-liver axis for the management and prevention of NAFLD.

Hepatoprotective and Antioxidant Activities of Oil from Baru Almonds (Dipteryx alata Vog.) in a Preclinical Model of Lipotoxicity and Dyslipidemia

The oil obtained from baru (Dipteryx alata Vog.) almonds exhibits high energy value and is reported in popular medicine for the treatment of rheumatic diseases and reproductive disturbances. Although baru oil is used in domestic cuisine, the chemical characterization of this oil and its effects on lipid metabolism are still poorly understood. Therefore, this study evaluated the fatty acid (FA) profile and the effects of baru oil on liver and aorta in a murine model of dyslipidemia. The chromatographic profile of baru oil showed high levels of unsaturated FAs, especially oleic acid. Saturated FAs, such as palmitic and lignoceric acids, were found in lower amounts. Hypercholesterolemia was induced in male Wistar rats by daily administration of a lipid emulsion by gavage for 15 weeks. Biochemical and histopathological analysis were performed on serum, aorta, and liver. The results demonstrated that animals developed marked hypercholesterolemia, liver steatosis, and increased lipid peroxidation in the aorta. Treatment with baru oil attenuated lipid peroxidation and drastically reduced liver damage, especially ballooning degeneration and steatosis. By restricting vascular and hepatic injury, this oil showed potential applicability as a functional food, reinforcing its use in popular medicine and domestic cuisine.

Association of non-alcoholic fatty liver disease with cardiovascular disease and subclinical atherosclerosis

Non-alcoholic fatty liver disease (NAFLD) refers to fatty infiltration of liver in the absence of significant alcohol intake, use of steatogenic medication, or hereditary disorders. It is a common cause of chronic liver disease with a worldwide estimated prevalence ranging from 6.3% to 33%. The NAFLD is considered a hepatic manifestation of the metabolic syndrome. Insulin resistance and increased oxidative stress are central to pathogenesis of NAFLD, and risk factors include metabolic syndrome, diabetes mellitus, obesity, lack of physical activity, smoking, and high fat diet. NAFLD is associated with higher mortality as compared to the general population with cardiovascular disease being the most common cause of death. The NAFLD is associated with a higher prevalence of subclinical atherosclerosis as evidenced by odds of higher coronary artery calcification, higher average and maximum carotid intima-media thickness. It is also associated with stiff arteries as evidenced by higher cardio-ankle vascular index and higher brachial-ankle pulse wave velocity. Increasing evidence has linked NAFLD with atherosclerotic cardiovascular diseases. The NAFLD is associated with a higher prevalence of coronary artery disease (CAD), more severe CAD, poor coronary collateral development, and higher incidence of coronary events. The NAFLD is also associated with ischemic stroke. Studies have shown that the association between NAFLD and atherosclerotic cardiovascular diseases is independent of shared risk factors.

New Aspects of Lipotoxicity in Nonalcoholic Steatohepatitis

NASH is becoming increasingly common worldwide because of the growing global prevalence of obesity and consequently NAFLD. Unfortunately, the mechanism of progression of NAFLD to NASH and then cirrhosis is not completely understood. Several factors, including insulin resistance, inflammation, oxidative stress, lipotoxicity, and bile acid (BA) toxicity, have been reported to be associated with NASH progression. The release of fatty acids from dysfunctional and insulin-resistant adipocytes results in lipotoxicity, which is caused by the ectopic accumulation of triglyceride-derived toxic metabolites and the subsequent activation of inflammatory pathways, cellular dysfunction, and lipoapoptosis. Adipose tissue (AT), especially visceral AT, comprises multiple cell populations that produce adipokines and insulin-like growth factor, plus macrophages and other immune cells that stimulate the development of lipotoxic liver disease. These biomolecules have been recently linked with many digestive diseases and gastrointestinal malignancies such as hepatocellular carcinoma. This made us question what role lipotoxicity has in the natural history of liver fibrosis. Therefore, this review focuses on the close relationship between AT and NASH. A good comprehension of the pathways that are related to dysregulated AT, metabolic dysfunction, and hepatic lipotoxicity will result in the development of prevention strategies and promising therapeutics for patients with NASH.

Current Treatment of Nonalcoholic Fatty Liver Disease/Nonalcoholic Steatohepatitis

Treatment of nonalcoholic fatty liver disease (NAFLD)/nonalcoholic steatohepatitis (NASH) is focused on patients with NASH because they are at highest risk for progressive liver disease. Current first-line treatment consists of lifestyle modifications. Patients should lose at least 7% to 10% of body weight via a combination of physical exercise and calorie restriction dieting. Surgical or endoscopic surgery for weight loss can be considered in obese patients, depending on degree of excess body weight and comorbidities. There is no currently approved pharmacotherapy for NASH. Vitamin E and pioglitazone have the most evidence of therapeutic efficacy but have limitations. The treatment modality chosen should be individualized.

The intestinal barrier: a fundamental role in health and disease

The gastrointestinal mucosa constitutes a critical barrier where millions of microbes and environmental antigens come in close contact with the host immune system. Intestinal barrier defects have been associated with a broad range of diseases and therefore denote a new therapeutic target. Areas covered: This review is based on an extensive literature search in PubMed of how the intestinal barrier contributes to health and as a trigger for disease. It discusses the anatomy of the intestinal barrier and explains the available methods to evaluate its function. Also reviewed is the importance of diet and lifestyle factors on intestinal barrier function, and three prototypes of chronic diseases (inflammatory bowel disease, celiac disease and nonalcoholic fatty liver disease) that have been linked to barrier defects are discussed. Expert commentary: The intestinal barrier has been investigated by various methods, but correlation of results across studies is difficult, representing a major shortcoming in the field. New upcoming techniques and research on the effect of barrier-restoring therapeutics may improve our current understanding of the gut barrier, and provide a step forward towards personalised medicine.

Antioxidant dietary approach in treatment of fatty liver: New insights and updates

Non-alcoholic fatty liver disease (NAFLD) is a common clinicopathological condition, encompassing a range of conditions caused by lipid deposition within liver cells. To date, no approved drugs are available for the treatment of NAFLD, despite the fact that it represents a serious and growing clinical problem in the Western world. Identification of the molecular mechanisms leading to NAFLD-related fat accumulation, mitochondrial dysfunction and oxidative balance impairment facilitates the development of specific interventions aimed at preventing the progression of hepatic steatosis. In this review, we focus our attention on the role of dysfunctions in mitochondrial bioenergetics in the pathogenesis of fatty liver. Major data from the literature about the mitochondrial targeting of some antioxidant molecules as a potential treatment for hepatic steatosis are described and critically analysed. There is ample evidence of the positive effects of several classes of antioxidants, such as polyphenols (i.e., resveratrol, quercetin, coumestrol, anthocyanins, epigallocatechin gallate and curcumin), carotenoids (i.e., lycopene, astaxanthin and fucoxanthin) and glucosinolates (i.e., glucoraphanin, sulforaphane, sinigrin and allyl-isothiocyanate), on the reversion of fatty liver. Although the mechanism of action is not yet fully elucidated, in some cases an indirect interaction with mitochondrial metabolism is expected. We believe that such knowledge will eventually translate into the development of novel therapeutic approaches for fatty liver.

The Fatty Liver Index (FLI) Relates to Diabetes-Specific Parameters and an Adverse Lipid Profile in a Cohort of Nondiabetic, Dyslipidemic Patients

BACKGROUND

Patients with hyperlipidemia are at high risk for developing a fatty liver. The fatty liver index (FLI) is a noninvasive and well-established method for the estimation of a fatty liver. However, little is known about the metabolic characterization of nondiabetic treated patients with hyperlipidemia who have different risk levels for a fatty liver.

METHODS

In this study, 74 nondiabetic patients with hyperlipidemia were divided into 3 groups according to their fatty liver index. A comparison of metabolic characteristics was done. These characteristics included intima media thickness (IMT) and nutritional habits, which were further divided into FLI subgroups with low, intermediate, and high risk for a fatty liver.

RESULTS

Patients with hyperlipidemia, with a high risk for a fatty liver (FLI ≥ 60), had subclinical elevations in parameters of carbohydrate metabolism (insulin, fasting plasma glucose, C-peptide) including a higher insulin resistance (quantitative insulin sensitivity check index, QUICKI) compared to lower FLI groups. These patients also presented a higher risk for a metabolic syndrome (p = 0.018), as well as an adverse lipid profile (e.g., high-density lipoprotein [HDL] cholesterol, triglycerides [TG]-HDL ratio). FLI group 3 was characterized by significantly lower levels of omega-3 fatty acids (p = 0.048).

CONCLUSION

The fatty liver index relates to diabetes-specific parameters and an adverse lipid profile and is an appropriate index for risk evaluation of metabolic syndrome.

Adenosine A2a receptor stimulation blocks development of nonalcoholic steatohepatitis in mice by multilevel inhibition of signals that cause immunolipotoxicity

Lipotoxicity and immunoinflammation are associated with the evolution of steatosis toward nonalcoholic steatohepatitis (NASH). This study reports the ability of adenosine A2a receptor (A2aR) activation to inhibit NASH development by modulating the responses of CD4⁺ T-helper (Th) cells to avoid an immuno-mediated potentiation of lipotoxicity. The effect of the A2aR agonist CGS21680 on immunoinflammatory signals, CD4⁺Th cell infiltration and immunolipotoxicity was analyzed in steatotic C57BL/6 mice fed with a methionine-choline-deficient (MCD) diet and in mouse hepatocytes exposed to palmitic acid (PA). CGS21680 inhibited NASH development in steatotic mice and decreased cytokines and chemokines involved in Th cell recruitment or polarization (namely CXCL10, CCL2, tumor necrosis factor alfa [TNFα], tumor growth factor [TGFβ], and IL-12). CGS21680 also reduced the expansion of Th17, Th22, and Th1 cells and increased the immunosuppressive activity of T regulatory cells. In PA-treated mice hepatocytes, CGS21680 inhibited the production of CXCL10, TNFα, TGFβ, IL-12, and CCL2; CGS21680 also prevented JNK-dependent lipotoxicity and its intensification by IL-17 or IL-17 plus IL-22 through Akt/PI3-kinase stimulation and inhibition of the negative regulator of PI3-kinase, (phosphatase and tensin homologue deleted from chromosome 10 (PTEN), which is upregulated by IL-17. In MCD livers, CGS21680 reduced JNK activation and PTEN expression and increased Akt phosphorylation. In conclusion, A2aR stimulation inhibited NASH development by reducing Th17 cell expansion and inhibiting the exacerbation of the IL-17-induced JNK-dependent lipotoxicity. These data promote the implementation of further studies to evaluate the potential clinical application of A2aR agonists that, by being able to function as both cytoprotective and immunomodulatory agents, could efficiently antagonize the multi-faced pathogenesis of NASH.

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.

Mitochondrial DNA from hepatocytes as a ligand for TLR9: Drivers of nonalcoholic steatohepatitis?

Nonalcoholic fatty liver disease (NAFLD) is the most common liver disease worldwide, affecting approximately one third of the Western world. It consists of a wide spectrum of liver disorders, ranging from fatty liver to nonalcoholic steatohepatitis (NASH), which consists of steatosis, ballooning injury and inflammation. Despite an alarming growth in the statistics surrounding NAFLD, there are as yet no effective therapies for its treatment. Innate immune signaling has been thought to play a significant role in initiating and augmenting hepatic inflammation, contributing to the transition from nonalcoholic fatty liver to NASH. An immune response is triggered by countless signals called damage-associated molecular patterns (DAMPs) elicited by lipid-laden and damaged hepatocytes, which are recognized by pattern recognition receptors (PRRs) on hepatic immune cells to initiate inflammatory signaling. In this editorial, in addition to summarizing innate immune signaling in NAFLD and discussing potential therapies that target innate immune pathways, we have described a recent study that demonstrated that mitochondrial DNA serves as a DAMP activating a hepatic PRR, TLR9, in mice and in the plasma of NASH patients. In addition to identifying a new ligand for TLR9 during NASH progression, the study shows that blocking TLR9 reverses NASH, paving the way for the development of future NASH therapy.

Concise Review: Current Status and Future Directions on Research Related to Nonalcoholic Fatty Liver Disease

Considered a feature of the metabolic syndrome, nonalcoholic fatty liver disease (NAFLD), is associated with insulin resistance, type 2 diabetes, obesity and drug toxicity. Its prevalence is estimated at about 30% in western countries mainly due to sedentary life styles and high fat diets. Genome-wide association studies have identified polymorphisms in several genes, for example, PNPLA3, and TM6SF2 which confer susceptibility to NAFLD. Here, we review recent findings in the NAFLD field with a particular focus on published transcriptomics datasets which we subject to a meta-analysis. We reveal a common gene signature correlating with the progression of the disease from steatosis and steatohepatitis and reveal that lipogenic and cholesterol metabolic pathways are main actors in this signature. We propose the use of disease-in-a-dish models based on hepatocyte-like cells derived from patient-specific induced pluripotent stem cells (iPSC). These will enable investigations into the contribution of genetic background in the progression from NALFD to non-alcoholic steatohepatitis. Furthermore, an iPSC-based approach should aid in the elucidation of the function of new biomarkers, thus enabling better diagnostic tests and validation of potential drug targets. Stem Cells 2017;35:89-96.